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  • 201.
    Andersson, G
    et al.
    Uppsala universitet, Medicinska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper.
    Juris, L
    Institutionen för neurovetenskap. psykiatri, UAS.
    Kaldo, V
    Baguley, DM
    Larsen, HC
    Uppsala universitet, Medicinska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper.
    Ekselius, L
    Institutionen för neurovetenskap. psykiatri, UAS.
    Hyperacusis - ett outforskat område. Kognitiv beteendeterapi kan lindra besvären vid ljudöverkänslighet, ett tillstånd med många frågetecken.2005Inngår i: Läkartidningen, Vol. 105, s. 3210-3212Artikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
  • 202.
    Andersson, G
    et al.
    Uppsala universitet, Medicinska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper.
    Larsen, HC
    Uppsala universitet, Medicinska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper.
    Cognitive-behavioural treatment of tinnitus in otosclerosis: a case-report.1997Inngår i: Behav Cognit Psychother, Vol. 25, s. 79-Artikkel i tidsskrift (Fagfellevurdert)
  • 203.
    Andersson, G
    et al.
    Uppsala universitet, Medicinska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper.
    Lyttkens, L
    Uppsala universitet, Medicinska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper.
    Acupuncture for tinnitus: time to stop?1996Inngår i: Scand Audiol, Vol. 25, s. 273-Artikkel i tidsskrift (Fagfellevurdert)
  • 204.
    Andersson, G
    et al.
    Uppsala universitet, Medicinska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper.
    McKenna, L
    Contributions of clinical psychology in audiology: tinnitus and hearing impairment.1997Inngår i: Clin Psychol Psychother, Vol. 4, s. 42-Artikkel i tidsskrift (Fagfellevurdert)
  • 205.
    Andersson, G
    et al.
    Uppsala universitet, Medicinska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper.
    McKenna, L
    Tinnitus masking and depression.1998Inngår i: Audiology, Vol. 37, s. 174-Artikkel i tidsskrift (Fagfellevurdert)
  • 206.
    Andersson, G
    et al.
    Uppsala universitet, Medicinska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper.
    Persson, K
    Melin, L
    Larsen, HC
    Uppsala universitet, Medicinska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper.
    Actual and perceived postural sway during balance specific and proprioceptive stimulation.1998Inngår i: Acta Oto-Laryngol., Vol. 118, s. 465-Artikkel i tidsskrift (Fagfellevurdert)
  • 207.
    Andersson, Gerhard
    Uppsala universitet, Medicinska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper.
    Clinical Aspects of Tinnitus- Course, Cognition, PET, and the Internet2000Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The purpose of this thesis was to develop novel ways to study tinnitus, to investigate the course of tinnitus, and to study the effects of cognitive-behaviour therapy on tinnitus related distress. Data from 377 tinnitus patients were collected.

    A group of 216 patients completed audiological measures and were assessed in a structured interview. The Klockhoff and Lindblom's grading system was used and its inter-rater reliability assessed in a subsample showing a high degree of correspondence. A discriminant analysis showed that a substantial proportion of patients could be correctly classified into grade II or III, by measures of pitch, minimal masking level of tinnitus, avoidance of situations because of tinnitus, and tolerance in relation to onset.

    Using tests developed in cognitive psychology, it was found that tinnitus patients had impaired performance. There was no evidence for an attentional bias towards tinnitus related words using a computerized emotional Stroop task, but masking sounds of an "on-and-off" character were more disruptive than constant masking when patients performed the digit-symbol test. It is suggested that tinnitus distress may be increased by the 'changing-state' character of the tinnitus signal, or alternatively by intermittent masking sounds.

    In a case-study a patient received an i.v. injection of lidocaine while Positron Emission Tomograpy was conducted. The brain activity associated with tinnitus included the left primary, secondary and integrative auditory brain areas, as well as right paralimbic areas related to negative feelings. The precuneus (Brodmann area 7) might be a brain area involved in the aversiveness associated with tinnitus.

    Using a tinnitus questionnaire as the dependent measure it was found that tinnitus maskability at admission predicted distress at follow-up for an average of five years following admission. Some improvement in tinnitus occurred over time, but this was more evident in patients who had received a cognitive-behavioural treatment program.

    The effect of an Internet based cognitive-behavioural self-help treatment program for tinnitus was investigated showing a high dropout rate, but with positive results in that the treated patients improved.

  • 208.
    Andersson, Gerhard
    et al.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper.
    Asmundson, Gordon J. G.
    Denev, Johanna
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Nilsson, Johanna
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Larsen, Hans Christian
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper.
    A controlled trial of cognitive-behavior therapy combined with vestibular rehabilitation in the treatment of dizziness2006Inngår i: Behaviour Research and Therapy, ISSN 0005-7967, E-ISSN 1873-622X, Vol. 44, nr 9, s. 1265-1273Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Dizziness is a common and often untreated symptom in the general population. The aim of this study was to investigate the effects of a combined cognitive-behavioral/vestibular rehabilitation (VR) program, using a randomized control design. A total of 29 participants were randomized to treatment consisting of psychoeducation, vestibular exercises, relaxation and cognitive interventions, or to serve as waiting list controls. Measures of dizziness-related handicap, dizziness-provoking movements, and daily diary registrations of dizziness symptoms at pre- and post-treatment showed statistically significant improvements in many domains, which translated to moderate effect sizes. These findings provide preliminary support for the combination of Cognitive-behavioral therapy (CBT) and VR methods in the treatment of dizziness.

  • 209.
    Andersson, Gerhard
    et al.
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Ekvall, Lars
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Öron-, näs- och halssjukdomar.
    Kinnefors, Anders
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Öron-, näs- och halssjukdomar.
    Nyberg, Gunnar
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för neurovetenskap, Neurokirurgi.
    Rask-Andersen, Helge
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Öron-, näs- och halssjukdomar.
    Evaluation of quality of life and symptoms after translabyrinthine acoustic neuroma surgery1997Inngår i: The American journal of otology, ISSN 0192-9763, Vol. 18, nr 4, s. 421-426Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    OBJECTIVE:

    This study aimed to describe the consequences of acoustic neuroma surgery in terms of symptoms and quality of life.

    STUDY DESIGN:

    This study was a retrospective case review.

    SETTING:

    The surgery was conducted in Uppsala, Sweden.

    PATIENTS:

    A consecutive sample of acoustic neuroma patients operated on between 1988 and 1994.

    INTERVENTION:

    All patients had been operated on with the translabyrinthine technique.

    MAIN OUTCOME MEASURES:

    A questionnaire was constructed including questions about the surgery and symptoms. The House and Brackmann scale was used for grading facial function and the Brackmann and Bars scale was used for self-assessment of facial function.

    RESULTS:

    Follow-up data were collected by a postal questionnaire sent out and returned by 141 patients, which yielded a 90% response rate. Normal to moderately impaired facial function (House I-III) was evident in 85.2% of patients, although residual facial problems were reported. Most considered hearing to be worse after surgery (80%), and tinnitus was found in 60% of the sample. Balance problems (45%), dizziness (19%), and headache/pain (22%) were also reported. Work ability was affected in 23%, and 37% reported a continued need for medical consultations, mainly because of facial problems and pain. Most (89%) were pleased with the preoperative information.

    CONCLUSIONS:

    This study showed that few patients with acoustic neuroma had experienced negative social consequences after surgery. Although not linked to the operation, residual symptoms were reported that may necessitate further rehabilitation.

  • 210.
    Andersson, Gerhard
    et al.
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Kinnefors, Anders
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Öron-, näs- och halssjukdomar.
    Ekvall, Lars
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Öron-, näs- och halssjukdomar.
    Rask-Andersen, Helge
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Öron-, näs- och halssjukdomar.
    Tinnitus and translabyrinthine acoustic neuroma surgery1997Inngår i: Audiology & neuro-otology, ISSN 1420-3030, E-ISSN 1421-9700, Vol. 2, nr 6, s. 403-409Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The purpose of this investigation was to study the effects of translabyrinthine acoustic neuroma surgery on tinnitus in a consecutive sample of patients operated on between 1988 and 1994 in Uppsala (Sweden). A postal questionnaire was returned by 141 patients, yielding a 90% response rate without reminder. The results showed that tinnitus was experienced by 70% of the patients before surgery and 60% after surgery. In general, low degrees of tinnitus distress were found, which was confirmed by the questionnaire results. Ratings of tinnitus distress after surgery, using the Klockhoff and Lindblom grading system, showed that 48% had tinnitus of grade I, 46% of grade II, and 6% of grade III. Pre- and postsurgery grading of distress did not change significantly. There was a 35% risk for developing tinnitus when no preoperative tinnitus was present and a 15% chance that tinnitus disappears when present preoperatively.

  • 211.
    Andersson, Gerhard
    et al.
    Uppsala universitet, Medicinska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper.
    Porsaeus, Daniel
    Wiklund, Magnus
    Kaldo, Viktor
    Larsen, Hans Christian
    Uppsala universitet, Medicinska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper.
    Treatment of tinnitus in the elderly: a controlled trial of cognitive behavior therapy.2005Inngår i: Int J Audiol, ISSN 1499-2027, Vol. 44, nr 11, s. 671-5Artikkel i tidsskrift (Fagfellevurdert)
  • 212.
    Andersson, Gerhard
    et al.
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Sandberg, Susanne
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Rydell, Ann Margret
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Gerdin, Bengt
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Plastikkirurgi.
    Social competence and behaviour problems in burned children2003Inngår i: Burns, ISSN 0305-4179, E-ISSN 1879-1409, Vol. 29, nr 1, s. 25-30Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The aim of this study was to collect follow-up data on social competence and behavioural problems in a sample of Swedish burned children and to compare the results with normative data from a reference group of children comparable in age, socio-economic status and gender. Parents of 44 children (55% response rate) aged 7-12 years were asked to complete a questionnaire booklet including the Children's Behaviour Questionnaire (CBQ) and the Social Competence Inventory (SCI). Data from the children's teachers were also collected for 20 children using the same booklet. In addition, data on TBSA, localisation of injury, and other background factors were collected. Results showed that the burned children were rated by their parents as showing lesser degrees of social initiative and more externalising problems and concentration problems compared with the control group. Teachers rated the burn injured children as having less prosocial orientation, more externalising problems, and more concentration problems. No clear effects were found for gender and characteristics of the burn injury. Results on the Social Competence Inventory were associated with scores on the Children's Behaviour Questionnaire.The findings are consistent with previous research in that the differences found were relatively small. However, they do call for attention to the possible adverse effects of growing up with a burn injury, but also to the possible pre-morbid characteristics that may be related to the injury.

  • 213. Andersson, Gustav
    et al.
    Wennersten, Christoffer
    Gaber, Alexander
    Boman, Karolina
    Nodin, Bjorn
    Uhlen, Mathias
    Segersten, Ulrika
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Urologkirurgi.
    Malmström, Per-Uno
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Urologkirurgi.
    Jirstrom, Karin
    Reduced expression of ezrin in urothelial bladder cancer signifies more advanced tumours and an impaired survival: validatory study of two independent patient cohorts2014Inngår i: BMC Urology, ISSN 1471-2490, E-ISSN 1471-2490, Vol. 14, s. 36-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background: Reduced membranous expression of the cytoskeleton-associated protein ezrin has previously been demonstrated to correlate with tumour progression and poor prognosis in patients with T1G3 urothelial cell carcinoma of the bladder treated with non-maintenance Bacillus Calmette-Guerin (n = 92), and the associations with adverse clinicopathological factors have been validated in another, unselected, cohort (n = 104). In the present study, we examined the prognostic significance of ezrin expression in urothelial bladder cancer in a total number of 442 tumours from two independent patient cohorts. Methods: Immunohistochemical expression of ezrin was evaluated in tissue microarrays with tumours from one retrospective cohort of bladder cancer (n = 110; cohort I) and one population-based cohort (n = 342; cohort II). Classification regression tree analysis was applied for selection of prognostic cutoff. Kaplan-Meier analysis, log rank test and Cox regression proportional hazards' modeling were used to evaluate the impact of ezrin on 5-year overall survival (OS), disease-specific survival (DSS) and progression-free survival (PFS). Results: Ezrin expression could be evaluated in tumours from 100 and 342 cases, respectively. In both cohorts, reduced membranous ezrin expression was significantly associated with more advanced T-stage (p < 0.001), high grade tumours (p < 0.001), female sex (p = 0.040 and p = 0.013), and membranous expression of podocalyxin-like protein (p < 0.001 and p = 0.009). Moreover, reduced ezrin expression was associated with a significantly reduced 5-year OS in both cohorts (HR = 3.09 95% CI 1.71-5.58 and HR = 2.15(1.51-3.06), and with DSS in cohort II (HR = 2.77, 95% CI 1.78-4.31). This association also remained significant in adjusted analysis in Cohort I (HR1.99, 95% CI 1.05-3.77) but not in Cohort II. In pTa and pT1 tumours in cohort II, there was no significant association between ezrin expression and time to progression. Conclusions: The results from this study validate previous findings of reduced membranous ezrin expression in urothelial bladder cancer being associated with unfavourable clinicopathological characteristics and an impaired survival. The utility of ezrin as a prognostic biomarker in transurethral resection specimens merits further investigation.

  • 214.
    Andersson, Hanna
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Anestesiologi och intensivvård.
    Reduced Preoperative Fasting in Children2019Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Preoperative fasting is recommended in order to reduce the risk of perioperative pulmonary aspiration. However, preoperative fasting may have negative effects on patient wellbeing and homeostasis. In this thesis, more lenient regimens for preoperative fasting in elective paediatric patients were assessed, with the aim to further improve preoperative fasting regimens.

    Paper I investigated if paediatric patients allowed to drink clear fluids until called to surgery, had an increased risk of pulmonary aspiration. The incidence of perioperative pulmonary aspiration in children allowed free clear fluids until called to surgery was 3 in 10 000, as compared to 1-10 in 10 000 in previous studies where longer fasting intervals were studied. Hence, no increase of incidence for pulmonary aspiration was found.

    Paper II investigated actual fasting times for clear fluids when applying two-hour fasting for clear fluids, and zero-hour fasting for clear fluids. When applying two-hour fasting, children were fasted median four hours for clear fluids. After transitioning to zero-hour fasting, median fasting time decreased to one hour, and the incidence of children fasting for more than six hours decreased from 35 % to 6 %. Abandoning the time limit for clear fluids significantly reduced the proportion of patients fasting for extended periods.

    Paper III assessed gastric content volume after a light breakfast in children scheduled for elective general anaesthesia. Patients were examined with gastric ultrasound four hours after a light breakfast. Of the 20 patients included in the study, 15 had an empty stomach, 4 had clear fluids < 0.5 ml kg-1 and one had solid content in the stomach. A light breakfast preoperatively might be safe, but amount and caloric restriction is needed to avoid the risk of perioperative pulmonary aspiration.

    Paper IV investigated preoperative weight loss, glucose level and ketone bodies in paediatric patients presenting for elective surgery. The outcomes were tested for correlation to preoperative fasting times. Of the 43 children enrolled in the study, three had weight loss of more than 5 %, five children presented with blood glucose level < 3.3 mmol l-1, and 11 children presented with ketone bodies > 0.6 mmol l-1. There was no correlation between fasting time, and the respective outcomes. Even with a lenient fasting regimen, there is risk of mild preoperative dehydration, hypoglycaemia and ketogenesis.

    In conclusion, the results obtained in the present thesis supports the shift to more lenient preoperative fasting regimens for clear fluids in elective paediatric patients.

    Delarbeid
    1. Low incidence of pulmonary aspiration in children allowed intake of clear fluids until called to the operating suite
    Åpne denne publikasjonen i ny fane eller vindu >>Low incidence of pulmonary aspiration in children allowed intake of clear fluids until called to the operating suite
    2015 (engelsk)Inngår i: Pediatric Anaesthesia, ISSN 1155-5645, E-ISSN 1460-9592, Vol. 25, nr 8, s. 770-777Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    BACKGROUND: International guidelines recommend 2 h of clear fluid fasting prior to general anesthesia. The pediatric anesthesia unit of Uppsala University Hospital has been implementing a more liberal fasting regime for more than a decade; thus, children scheduled for elective procedures are allowed to drink clear fluids until called to the operating suite.

    AIM: To determine the incidence of perioperative pulmonary aspiration in pediatric patients allowed unlimited intake of clear fluids prior to general anesthesia.

    METHOD: Elective pediatric procedures between January 2008 and December 2013 were examined retrospectively by reviewing anesthesia charts and discharge notes in the electronic medical record system. All notes from the care event and available chest x-rays were examined for cases showing vomiting, regurgitation, and/or aspiration. Pulmonary aspiration was defined as radiological findings consistent with aspiration and/or postoperative symptoms of respiratory distress after vomiting during anesthesia.

    RESULTS: Of the 10 015 pediatric anesthetics included, aspiration occurred in three (0.03% or 3 in 10 000) cases. No case required cancellation of the surgical procedure, intensive care or ventilation support, and no deaths attributable to aspiration were found. Pulmonary aspiration was suspected, but not confirmed by radiology or continuing symptoms, in an additional 14 cases.

    CONCLUSION: Shortened fasting times may improve the perioperative experience for parents and children with a low risk of aspiration.

    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-256491 (URN)10.1111/pan.12667 (DOI)000357730600003 ()25940831 (PubMedID)
    Tilgjengelig fra: 2015-06-24 Laget: 2015-06-24 Sist oppdatert: 2019-10-06bibliografisk kontrollert
    2. Introducing the 6-4-0 fasting regimen and the incidence of prolonged preoperative fasting in children
    Åpne denne publikasjonen i ny fane eller vindu >>Introducing the 6-4-0 fasting regimen and the incidence of prolonged preoperative fasting in children
    2018 (engelsk)Inngår i: Pediatric Anaesthesia, ISSN 1155-5645, E-ISSN 1460-9592, Vol. 28, nr 1, s. 46-52Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Background

    Children often starve for longer than recommended by current preoperative fasting guidelines.

    Aims

    We studied the effects of implementing a more lenient fasting regimen on the duration of clear fluid fasting, as well as the incidence of extended fasting in children.

    Methods

    Preoperative duration of clear fluid fasting was recorded for patients scheduled for procedures in a unit applying the standard 6-4-2 fasting regimen. This group was compared with a cohort in the same unit 1year after transitioning to a 6-4-0 fasting regimen. The latter includes no limitations on clear fluid intake until the child is called to theater. A third cohort from a unit in which the 6-4-0 fasting regimen has been implemented for over a decade was also studied for comparison.

    Results

    Patients fasting according to the 6-4-2 fasting regimen (n=66) had a median fasting time for clear fluids of 4.0h and a 33.3% incidence of fasting more than 6h. After transitioning to the 6-4-0 fasting regimen (n=64), median duration of fasting for clear fluids decreased to 1.0h, and the incidence of fasting more than 6h decreased to 6.3%. In the second unit (n=73), median fasting time was 2.2h and the proportion of patients fasting more than 6h was 21.9%.

    Conclusion

    The introduction and implementation of the 6-4-0 fasting regimen reduces median fluid fasting duration and the number of children subjected to extended fasting.

    Emneord
    anesthesia, children, fasting, fluids, preoperative
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-343890 (URN)10.1111/pan.13282 (DOI)000417604600008 ()29168341 (PubMedID)
    Tilgjengelig fra: 2018-03-05 Laget: 2018-03-05 Sist oppdatert: 2019-10-06bibliografisk kontrollert
    3. Gastric content assessed with gastric ultrasound in paediatric patients prescribed a light breakfast prior to general anaesthesia. A prospective observational study.
    Åpne denne publikasjonen i ny fane eller vindu >>Gastric content assessed with gastric ultrasound in paediatric patients prescribed a light breakfast prior to general anaesthesia. A prospective observational study.
    (engelsk)Inngår i: Artikkel i tidsskrift (Annet vitenskapelig) Accepted
    Abstract [en]

    Background:

    A light breakfast has been found to empty from the stomach within four hours in healthy volunteers.

    Aim

    The aim of this study was to investigate if a light breakfast of yoghurt or gruel empties from the stomach within four hours, in children scheduled for general anaesthesia.

    Method:

    In this observational cohort study, children aged 1-6 years, scheduled for elective general anaesthesia were prescribed free intake of yoghurt or gruel four hours prior to induction. They were subsequently examined with gastric ultrasound within four hours of ingestion. In case of gastric contents, the gastric antral area was measured, and gastric content volume was calculated.

    Results:

    Twenty children were included in the study and the ingested amount of gruel or yoghurt ranged 2.5-25 ml kg-1. In 15 cases, the stomach was empty with juxtaposed walls and no further measurements were made. In four cases, there was fluid present in the stomach, but the calculated gastric contents were < 0.5 ml kg-1. One patient had solids in the stomach and gastric content volume in this patient was calculated to 2.1 ml kg-1. The patient with solids present had ingested 25 ml kg-1 of gruel four hours prior to assessment. The planned procedure was therefore delayed one hour. There were no cases of pulmonary aspiration or vomiting.

    Conclusion:

    A light breakfast four hours prior to induction may be considered, but there is need for further studies on safe limits for the volume ingested.

    Emneord
    Ultrasound, General anesthesia, child < Age
    HSV kategori
    Forskningsprogram
    Anestesiologi och intensivvård
    Identifikatorer
    urn:nbn:se:uu:diva-394230 (URN)
    Tilgjengelig fra: 2019-10-05 Laget: 2019-10-05 Sist oppdatert: 2019-10-10
    4. Preoperative weight loss, hypoglycaemia and ketosis in elective paediatric patients, preliminary results from a prospective observational study
    Åpne denne publikasjonen i ny fane eller vindu >>Preoperative weight loss, hypoglycaemia and ketosis in elective paediatric patients, preliminary results from a prospective observational study
    (engelsk)Manuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Background

    New paediatric fasting guidelines allow free clear fluids up until one hour prior to surgery. At the paediatric anaesthesia department of Uppsala University Hospital, children are fasted six hours for solids, four hours for breast milk and are allowed free clear fluids up until called to theatre. Preoperative fasting is necessary to avoid perioperative pulmonary aspiration. However, extended fasting times have detrimental effects for fluid homeostasis and may cause hypoglycaemia and ketone bodies.

    Aim

    The aim of the current study was to investigate if preoperative weight loss, glucose level and ketone bodies were related to preoperative fasting times.

    Methods

    Paediatric patients aged 0-72 months were included in this prospective, observational study. All children included were instructed to fast from midnight for solids, four hours for breast milk or semi-solids and from when they are called to theatre for clear fluids. Fasting times were registered, and patient weight was measured in the evening prior to surgery, and before induction. Blood glucose and ketone body levels were measured before induction. Multiple regression was used to determine how fasting time affected the outcomes weight change, blood glucose level and ketone bodies, respectively.

    Results

    43 patients were enrolled. Three children had a weight loss of more than 5 %, five children presented with blood glucose level < 3.3 mmol l-1, and 11 children presented with ketone bodies > 0.6 mmol l-1. There was no correlation between fasting time and the respective outcomes.

    Conclusion

    Even with a lenient preoperative fasting regimen, mild dehydration or hypoglycaemia may occur. This methodology may be used in further studies of the effects of preoperative fasting in settings where dehydration may be more significant.

    Emneord
    General Anesthesia, child < Age, Dehydration, Fasting, Hypoglycaemia, Ketosis
    HSV kategori
    Forskningsprogram
    Anestesiologi och intensivvård; Anestesiologi och intensivvård
    Identifikatorer
    urn:nbn:se:uu:diva-394231 (URN)
    Tilgjengelig fra: 2019-10-05 Laget: 2019-10-05 Sist oppdatert: 2019-10-06
  • 215.
    Andersson, Hanna
    et al.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Anestesiologi och intensivvård.
    Elias, Eerola
    Frykholm, Peter
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Anestesiologi och intensivvård. Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Hedenstiernalaboratoriet.
    Preoperative weight loss, hypoglycaemia and ketosis in elective paediatric patients, preliminary results from a prospective observational studyManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Background

    New paediatric fasting guidelines allow free clear fluids up until one hour prior to surgery. At the paediatric anaesthesia department of Uppsala University Hospital, children are fasted six hours for solids, four hours for breast milk and are allowed free clear fluids up until called to theatre. Preoperative fasting is necessary to avoid perioperative pulmonary aspiration. However, extended fasting times have detrimental effects for fluid homeostasis and may cause hypoglycaemia and ketone bodies.

    Aim

    The aim of the current study was to investigate if preoperative weight loss, glucose level and ketone bodies were related to preoperative fasting times.

    Methods

    Paediatric patients aged 0-72 months were included in this prospective, observational study. All children included were instructed to fast from midnight for solids, four hours for breast milk or semi-solids and from when they are called to theatre for clear fluids. Fasting times were registered, and patient weight was measured in the evening prior to surgery, and before induction. Blood glucose and ketone body levels were measured before induction. Multiple regression was used to determine how fasting time affected the outcomes weight change, blood glucose level and ketone bodies, respectively.

    Results

    43 patients were enrolled. Three children had a weight loss of more than 5 %, five children presented with blood glucose level < 3.3 mmol l-1, and 11 children presented with ketone bodies > 0.6 mmol l-1. There was no correlation between fasting time and the respective outcomes.

    Conclusion

    Even with a lenient preoperative fasting regimen, mild dehydration or hypoglycaemia may occur. This methodology may be used in further studies of the effects of preoperative fasting in settings where dehydration may be more significant.

  • 216.
    Andersson, Hanna
    et al.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Anestesiologi och intensivvård.
    Frykholm, Peter
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Anestesiologi och intensivvård. Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Hedenstiernalaboratoriet.
    Gastric content assessed with gastric ultrasound in paediatric patients prescribed a light breakfast prior to general anaesthesia. A prospective observational study.Inngår i: Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    Background:

    A light breakfast has been found to empty from the stomach within four hours in healthy volunteers.

    Aim

    The aim of this study was to investigate if a light breakfast of yoghurt or gruel empties from the stomach within four hours, in children scheduled for general anaesthesia.

    Method:

    In this observational cohort study, children aged 1-6 years, scheduled for elective general anaesthesia were prescribed free intake of yoghurt or gruel four hours prior to induction. They were subsequently examined with gastric ultrasound within four hours of ingestion. In case of gastric contents, the gastric antral area was measured, and gastric content volume was calculated.

    Results:

    Twenty children were included in the study and the ingested amount of gruel or yoghurt ranged 2.5-25 ml kg-1. In 15 cases, the stomach was empty with juxtaposed walls and no further measurements were made. In four cases, there was fluid present in the stomach, but the calculated gastric contents were < 0.5 ml kg-1. One patient had solids in the stomach and gastric content volume in this patient was calculated to 2.1 ml kg-1. The patient with solids present had ingested 25 ml kg-1 of gruel four hours prior to assessment. The planned procedure was therefore delayed one hour. There were no cases of pulmonary aspiration or vomiting.

    Conclusion:

    A light breakfast four hours prior to induction may be considered, but there is need for further studies on safe limits for the volume ingested.

  • 217.
    Andersson, Hanna
    et al.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Anestesiologi och intensivvård.
    Hellström, Per M.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för medicinska vetenskaper, Gastroenterologi/hepatologi.
    Frykholm, Peter
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Anestesiologi och intensivvård.
    Introducing the 6-4-0 fasting regimen and the incidence of prolonged preoperative fasting in children2018Inngår i: Pediatric Anaesthesia, ISSN 1155-5645, E-ISSN 1460-9592, Vol. 28, nr 1, s. 46-52Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background

    Children often starve for longer than recommended by current preoperative fasting guidelines.

    Aims

    We studied the effects of implementing a more lenient fasting regimen on the duration of clear fluid fasting, as well as the incidence of extended fasting in children.

    Methods

    Preoperative duration of clear fluid fasting was recorded for patients scheduled for procedures in a unit applying the standard 6-4-2 fasting regimen. This group was compared with a cohort in the same unit 1year after transitioning to a 6-4-0 fasting regimen. The latter includes no limitations on clear fluid intake until the child is called to theater. A third cohort from a unit in which the 6-4-0 fasting regimen has been implemented for over a decade was also studied for comparison.

    Results

    Patients fasting according to the 6-4-2 fasting regimen (n=66) had a median fasting time for clear fluids of 4.0h and a 33.3% incidence of fasting more than 6h. After transitioning to the 6-4-0 fasting regimen (n=64), median duration of fasting for clear fluids decreased to 1.0h, and the incidence of fasting more than 6h decreased to 6.3%. In the second unit (n=73), median fasting time was 2.2h and the proportion of patients fasting more than 6h was 21.9%.

    Conclusion

    The introduction and implementation of the 6-4-0 fasting regimen reduces median fluid fasting duration and the number of children subjected to extended fasting.

  • 218.
    Andersson, Hanna
    et al.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Anestesiologi och intensivvård.
    Schmitz, Achim
    Univ Childrens Hosp Zürich, Dept Anesthesiol, Zürich, Switzerland.
    Frykholm, Peter
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Anestesiologi och intensivvård.
    Preoperative fasting guidelines in pediatric anesthesia: are we ready for a change?2018Inngår i: Current Opinion in Anaesthesiology, ISSN 0952-7907, E-ISSN 1473-6500, Vol. 31, nr 3, s. 342-348Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    Purpose of review: Study after study shows that prolonged fasting before anesthesia is common in children. Pediatric anesthesiologists around the world are concerned that the current guidelines may be part of the problem. This review focuses on what can be done about it.

    Recent findings: We discuss new insights into the physiology of gastric emptying of different categories of food and drink. The evidence for negative effects of prolonged fasting occurring in spite of implementation of the current guidelines is examined. We also critically appraise the concept of a strict association between fasting time and the risk of aspiration and discuss recent studies in which children have been allowed clear fluids less than 2 h before anesthesia induction.

    Summary: Accumulating evidence indicates that changes of the current guidelines for preoperative fasting should be considered for children undergoing elective procedures.

    Video abstract: http://links.lww.com/COAN/A50

  • 219.
    Andersson, Hanna
    et al.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Anestesiologi och intensivvård.
    Zarén, Björn
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Anestesiologi och intensivvård.
    Frykholm, Peter
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Anestesiologi och intensivvård.
    Low incidence of pulmonary aspiration in children allowed intake of clear fluids until called to the operating suite2015Inngår i: Pediatric Anaesthesia, ISSN 1155-5645, E-ISSN 1460-9592, Vol. 25, nr 8, s. 770-777Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    BACKGROUND: International guidelines recommend 2 h of clear fluid fasting prior to general anesthesia. The pediatric anesthesia unit of Uppsala University Hospital has been implementing a more liberal fasting regime for more than a decade; thus, children scheduled for elective procedures are allowed to drink clear fluids until called to the operating suite.

    AIM: To determine the incidence of perioperative pulmonary aspiration in pediatric patients allowed unlimited intake of clear fluids prior to general anesthesia.

    METHOD: Elective pediatric procedures between January 2008 and December 2013 were examined retrospectively by reviewing anesthesia charts and discharge notes in the electronic medical record system. All notes from the care event and available chest x-rays were examined for cases showing vomiting, regurgitation, and/or aspiration. Pulmonary aspiration was defined as radiological findings consistent with aspiration and/or postoperative symptoms of respiratory distress after vomiting during anesthesia.

    RESULTS: Of the 10 015 pediatric anesthetics included, aspiration occurred in three (0.03% or 3 in 10 000) cases. No case required cancellation of the surgical procedure, intensive care or ventilation support, and no deaths attributable to aspiration were found. Pulmonary aspiration was suspected, but not confirmed by radiology or continuing symptoms, in an additional 14 cases.

    CONCLUSION: Shortened fasting times may improve the perioperative experience for parents and children with a low risk of aspiration.

  • 220. Andersson, J
    et al.
    Lilja, A
    Hartvig, P
    Langstrom, B
    Gordh, T
    Uppsala universitet, Medicinska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper.
    Handwerker, H
    Torebjork, E
    Institutionen för neurovetenskap.
    Somototopic organisation along the central sulcus for pain localisation in humans as revealed by PET.1997Inngår i: Exp, Brain Res., Vol. 117, s. 192-Artikkel i tidsskrift (Fagfellevurdert)
  • 221.
    Andersson, Jacob
    et al.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Rättsmedicin.
    Thiblin, Ingemar
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Rättsmedicin.
    It is important not to assume an aetiology for the triad before the outcomes of diagnostic investigations2018Inngår i: Acta Paediatrica, ISSN 0803-5253, E-ISSN 1651-2227, Vol. 107, nr 8, s. 1308-1309Artikkel i tidsskrift (Annet vitenskapelig)
  • 222.
    Andersson, Jacob
    et al.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Rättsmedicin.
    Thiblin, Ingemar
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Rättsmedicin.
    National study shows that abusive head trauma mortality in Sweden was at least 10 times lower than in other Western countries.2018Inngår i: Acta Paediatrica, ISSN 0803-5253, E-ISSN 1651-2227, Vol. 107, nr 3, s. 477-483Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    AIM: The validity of the diagnostic criteria for abusive head trauma (AHT) and its attributes have been widely debated. This national study investigated the possibility of false positive and false negative cases of fatal AHT in Sweden.

    METHOD: This was a retrospective evaluation of the records of 733 deceased infants up to the age of 365 days who were examined during 1994-2013 at the six forensic medicine departments. All the records were scrutinised for possible cases of AHT.

    RESULTS: We included 12 cases, out of which eight had been diagnosed as AHT. Of these 12 infants, eight had a concomitant disease or perinatal illness, five were born prematurely, and three were twins. Figures from other Western countries would suggest 6-7 deaths per 100,000 per year in Sweden but in reality, there was a maximum possible incidence of 0.6 per 100,000 infants per year.

    CONCLUSION: The risk of unreported fatal AHT in Sweden was low and there may have been cases misdiagnosed as AHT. The at least 10 times lower incidence than has been reported from other Western countries, raises the question if previously reported higher incidences of fatal AHT have been exaggerated.

  • 223. Andersson, Jenny
    et al.
    Larsson, L.
    Klaar, S.
    Holmberg, Lars
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper. Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Endokrinkirurgi.
    Nilsson, J.
    Inganäs, M.
    Carlsson, G.
    Ohd, J.
    Rudenstam, C-M.
    Gustavsson, B.
    Bergh, J.
    Worse survival for TP53 (p53)-mutated breast cancer patients receiving adjuvant CMF2005Inngår i: Annals of Oncology, ISSN 0923-7534, E-ISSN 1569-8041, Vol. 16, nr 5, s. 743-8Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    BACKGROUND: TP53 has been described as a prognostic factor in many malignancies, including breast cancer. Whether it also might be a predictive factor with reference to chemo- and endocrine therapy is more controversial. PATIENTS AND METHODS: We investigated relapse-free (RFS), breast cancer-corrected (BCCS) and overall survival (OS) related to TP53 status in node-positive breast cancer patients that had received polychemotherapy [cyclophosphamide, methotrexate, 5-fluorouracil (CMF)] and/or endocrine therapy (tamoxifen). Sequence analyses of the whole TP53 coding region was performed in 376 patients operated on for primary breast cancer with axillary lymph node metastases between 1984 and 1989 (median follow-up time 84 months). RESULTS: TP53 mutations were found in 105 patients (28%). We found 90 (82%) of the 110 mutations in the more frequently analysed exons 5-8, while the other 20 (18%) were located in exons 3-4 and 9-10, respectively. Univariate analyses showed TP53 to be a significant prognostic factor with regard to RFS, BCCS and OS in patients who received adjuvant CMF. CONCLUSIONS: TP53 mutations might induce resistance to certain modalities of breast cancer therapy. Sequence-determined TP53 mutation was of negative prognostic value in the total patient population and in the CMF treated patients.

  • 224. Andersson, JL
    et al.
    Lilja, A
    Hartvig, P
    Langstrom, B
    Gordh, T
    Uppsala universitet, Medicinska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper.
    Handwerker, H
    Torebjork, E
    Institutionen för neurovetenskap.
    Somatotopic organization along the central sulcus, for pain localization in humans, as revealed by positron emission tomography.1998Inngår i: Exp Brain Res, Vol. 117, s. 192-Artikkel i tidsskrift (Fagfellevurdert)
  • 225.
    Andersson, Jonathan
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper.
    Water–fat separation in magnetic resonance imaging and its application in studies of brown adipose tissue2019Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Virtually all the magnetic resonance imaging (MRI) signal of a human originates from water and fat molecules. By utilizing the property chemical shift the signal can be separated, creating water- and fat-only images. From these images it is possible to calculate quantitative fat fraction (FF) images, where the value of each voxel is equal to the percentage of its signal originating from fat. In papers I and II methods for water–fat signal separation are presented and evaluated.

    The method in paper I utilizes a graph-cut to separate the signal and was designed to perform well even for a low signal-to-noise ratio (SNR). The method was shown to perform as well as previous methods at high SNRs, and better at low SNRs.

    The method presented in paper II uses convolutional neural networks to perform the signal separation. The method was shown to perform similarly to a previous method using a graph-cut when provided non-undersampled input data. Furthermore, the method was shown to be able to separate the signal using undersampled data. This may allow for accelerated MRI scans in the future.

    Brown adipose tissue (BAT) is a thermogenic organ with the main purpose of expending chemical energy to prevent the body temperature from falling too low. Its energy expending capability makes it a potential target for treating overweight/obesity and metabolic dysfunctions, such as type 2 diabetes. The most well-established way of estimating the metabolic potential of BAT is through measuring glucose uptake using 18F-fludeoxyglucose (18F-FDG) positron emission tomography (PET) during cooling. This technique exposes subjects to potentially harmful ionizing radiation, and alternative methods are desired. One alternative method is measuring the BAT FF using MRI.

    In paper III the BAT FF in 7-year olds was shown to be negatively associated with blood serum levels of the bone-specific protein osteocalcin and, after correction for adiposity, thigh muscle volume. This may have implications for how BAT interacts with both bone and muscle tissue.

    In paper IV the glucose uptake of BAT during cooling of adult humans was measured using 18F-FDG PET. Additionally, their BAT FF was measured using MRI, and their skin temperature during cooling near a major BAT depot was measured using infrared thermography (IRT). It was found that both the BAT FF and the temperature measured using IRT correlated with the BAT glucose uptake, meaning these measurements could be potential alternatives to 18F-FDG PET in future studies of BAT.

    Delarbeid
    1. Water-fat separation incorporating spatial smoothing is robust to noise
    Åpne denne publikasjonen i ny fane eller vindu >>Water-fat separation incorporating spatial smoothing is robust to noise
    2018 (engelsk)Inngår i: Magnetic Resonance Imaging, ISSN 0730-725X, E-ISSN 1873-5894, Vol. 50, s. 78-83, artikkel-id S0730-725X(18)30040-7Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    PURPOSE: To develop and evaluate a noise-robust method for reconstruction of water and fat images for spoiled gradient multi-echo sequences.

    METHODS: The proposed method performs water-fat separation by using a graph cut to minimize an energy function consisting of unary and binary terms. Spatial smoothing is incorporated to increase robustness to noise. The graph cut can fail to find a solution covering the entire image, in which case the relative weighting of the unary term is iteratively increased until a complete solution is found. The proposed method was compared to two previously published methods. Reconstructions were performed on 16 cases taken from the 2012 ISMRM water-fat reconstruction challenge dataset, for which reference reconstructions were provided. Robustness towards noise was evaluated by reconstructing images with different levels of noise added. The percentage of water-fat swaps were calculated to measure performance.

    RESULTS: At low noise levels the proposed method produced similar results to one of the previously published methods, while outperforming the other. The proposed method significantly outperformed both of the previously published methods at moderate and high noise levels.

    CONCLUSION: By incorporating spatial smoothing, an increased robustness towards noise is achieved when performing water-fat reconstruction of spoiled gradient multi-echo sequences.

    Emneord
    Chemical shift imaging, Dixon, Graph cuts, Multi-scale, Quadratic pseudo-Boolean optimization, Water-fat separation
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-347450 (URN)10.1016/j.mri.2018.03.015 (DOI)000434750700011 ()29601865 (PubMedID)
    Forskningsfinansiär
    Swedish Research Council, 2016-01040
    Tilgjengelig fra: 2018-04-03 Laget: 2018-04-03 Sist oppdatert: 2019-08-14bibliografisk kontrollert
    2. Separation of water and fat signal in whole-body gradient echo scans using convolutional neural networks
    Åpne denne publikasjonen i ny fane eller vindu >>Separation of water and fat signal in whole-body gradient echo scans using convolutional neural networks
    2019 (engelsk)Inngår i: Magnetic Resonance in Medicine, ISSN 0740-3194, E-ISSN 1522-2594, Vol. 82, nr 3, s. 1177-1186Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Purpose: To perform and evaluate water–fat signal separation of whole‐body gradient echo scans using convolutional neural networks.

    Methods: Whole‐body gradient echo scans of 240 subjects, each consisting of 5 bipolar echoes, were used. Reference fat fraction maps were created using a conventional method. Convolutional neural networks, more specifically 2D U‐nets, were trained using 5‐fold cross‐validation with 1 or several echoes as input, using the squared difference between the output and the reference fat fraction maps as the loss function. The outputs of the networks were assessed by the loss function, measured liver fat fractions, and visually. Training was performed using a graphics processing unit (GPU). Inference was performed using the GPU as well as a central processing unit (CPU).

    Results: The loss curves indicated convergence, and the final loss of the validation data decreased when using more echoes as input. The liver fat fractions could be estimated using only 1 echo, but results were improved by use of more echoes. Visual assessment found the quality of the outputs of the networks to be similar to the reference even when using only 1 echo, with slight improvements when using more echoes. Training a network took at most 28.6 h. Inference time of a whole‐body scan took at most 3.7 s using the GPU and 5.8 min using the CPU.

    Conclusion: It is possible to perform water–fat signal separation of whole‐body gradient echo scans using convolutional neural networks. Separation was possible using only 1 echo, although using more echoes improved the results.

    Emneord
    Dixon, convolutional neural network, deep learning, magnetic resonance imaging, neural network, water-fat separation
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-382933 (URN)10.1002/mrm.27786 (DOI)000485077600026 ()31033022 (PubMedID)
    Forskningsfinansiär
    Swedish Research Council, 2016-01040
    Tilgjengelig fra: 2019-05-07 Laget: 2019-05-07 Sist oppdatert: 2019-10-15bibliografisk kontrollert
    3. MRI estimates of brown adipose tissue in children - Associations to adiposity, osteocalcin, and thigh muscle volume
    Åpne denne publikasjonen i ny fane eller vindu >>MRI estimates of brown adipose tissue in children - Associations to adiposity, osteocalcin, and thigh muscle volume
    Vise andre…
    2019 (engelsk)Inngår i: Magnetic Resonance Imaging, ISSN 0730-725X, E-ISSN 1873-5894, Vol. 58, s. 135-142Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Context: Brown adipose tissue is of metabolic interest. The tissue is however poorly explored in children.

    Methods: Sixty-three 7-year old subjects from the Swedish birth-cohort Halland Health and Growth Study were recruited. Care was taken to include both normal weight and overweight children, but the subjects were otherwise healthy. Only children born full term were included. Water-fat separated whole-body MRI scans, anthropometric measurements, and measurements of fasting glucose and levels of energy homeostasis related hormones, including the insulin-sensitizer osteocalcin, were performed. The fat fraction (FF) and effective transverse relaxation time (T-2(star)) of suspected brown adipose tissue in the cervical-supraclavicular-axillary fat depot (sBAT) and the FFs of abdominal visceral (VAT) and subcutaneous adipose tissue (SAT) were measured. Volumes of sBAT, abdominal VAT and SAT, and thigh muscle volumes were measured.

    Results: The FF in the sBAT depot was lower than in VAT and SAT for all children. In linear correlations including sex and age as explanatory variables, sBAT FF correlated positively with all measures of adiposity (p < 0.01), except for VAT FF and weight, positively with sBAT T-2* (p = 0.036), and negatively with osteocalcin (p = 0.017). When adding measures of adiposity as explanatory variables, sBAT FF also correlated negatively with thigh muscle volume (p < 0.01).

    Conclusions: Whole-body water-fat MRI of children allows for measurements of sBAT. The FF of sBAT was lower than that of VAT and SAT, indicating presence of BAT. Future studies could confirm whether the observed correlations corresponds to a hormonally active BAT.

    sted, utgiver, år, opplag, sider
    ELSEVIER SCIENCE INC, 2019
    Emneord
    Brown adipose tissue, Magnetic resonance imaging, Adiposity, Osteocalcin, Muscle volume, Quantitative MRI
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-380416 (URN)10.1016/j.mri.2019.02.001 (DOI)000461412300018 ()30742901 (PubMedID)
    Forskningsfinansiär
    Swedish Research Council, 2013-3013Swedish Research Council, 2016-01040Region Västra Götaland
    Tilgjengelig fra: 2019-04-02 Laget: 2019-04-02 Sist oppdatert: 2019-08-14bibliografisk kontrollert
    4. Estimating the cold-induced brown adipose tissue glucose uptake rate measured by 18F-FDG PET using infrared thermography and water-fat separated MRI
    Åpne denne publikasjonen i ny fane eller vindu >>Estimating the cold-induced brown adipose tissue glucose uptake rate measured by 18F-FDG PET using infrared thermography and water-fat separated MRI
    Vise andre…
    2019 (engelsk)Inngår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, artikkel-id 12358Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Brown adipose tissue (BAT) expends chemical energy to produce heat, which makes it a potential therapeutic target for combating metabolic dysfunction and overweight/obesity by increasing its metabolic activity. The most well-established method for measuring BAT metabolic activity is glucose uptake rate (GUR) measured using 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET). However, this is expensive and exposes the subjects to potentially harmful radiation. Cheaper and safer methods are warranted for large-scale or longitudinal studies. Potential alternatives include infrared thermography (IRT) and magnetic resonance imaging (MRI). The aim of this study was to evaluate and further develop these techniques. Twelve healthy adult subjects were studied. The BAT GUR was measured using 18F-FDG PET during individualized cooling. The temperatures of the supraclavicular fossae and a control region were measured using IRT during a simple cooling protocol. The fat fraction and effective transverse relaxation rate of BAT were measured using MRI without any cooling intervention. Simple and multiple linear regressions were employed to evaluate how well the MRI and IRT measurements could estimate the GUR. Results showed that both IRT and MRI measurements correlated with the GUR. This suggest that these measurements may be suitable for estimating the cold-induced BAT GUR in future studies.

    Emneord
    brown adipose tissue, 18F-FDG positron emission tomography, infrared thermography, magnetic resonance imagingm PET/MRI, water–fat signal separation
    HSV kategori
    Forskningsprogram
    Radiologi
    Identifikatorer
    urn:nbn:se:uu:diva-390410 (URN)10.1038/s41598-019-48879-7 (DOI)000482564800014 ()31451711 (PubMedID)
    Forskningsfinansiär
    Swedish Research Council, 2016-01040Swedish Heart Lung Foundation, 2170492EXODIAB - Excellence of Diabetes Research in Sweden
    Tilgjengelig fra: 2019-08-09 Laget: 2019-08-09 Sist oppdatert: 2019-10-18bibliografisk kontrollert
  • 226.
    Andersson, Jonathan
    et al.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Radiologi.
    Ahlström, Håkan
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Radiologi. Antaros Med, Mölndal, Sweden.
    Kullberg, Joel
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Radiologi. Antaros Med, Mölndal, Sweden.
    Separation of water and fat signal in whole-body gradient echo scans using convolutional neural networks2019Inngår i: Magnetic Resonance in Medicine, ISSN 0740-3194, E-ISSN 1522-2594, Vol. 82, nr 3, s. 1177-1186Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Purpose: To perform and evaluate water–fat signal separation of whole‐body gradient echo scans using convolutional neural networks.

    Methods: Whole‐body gradient echo scans of 240 subjects, each consisting of 5 bipolar echoes, were used. Reference fat fraction maps were created using a conventional method. Convolutional neural networks, more specifically 2D U‐nets, were trained using 5‐fold cross‐validation with 1 or several echoes as input, using the squared difference between the output and the reference fat fraction maps as the loss function. The outputs of the networks were assessed by the loss function, measured liver fat fractions, and visually. Training was performed using a graphics processing unit (GPU). Inference was performed using the GPU as well as a central processing unit (CPU).

    Results: The loss curves indicated convergence, and the final loss of the validation data decreased when using more echoes as input. The liver fat fractions could be estimated using only 1 echo, but results were improved by use of more echoes. Visual assessment found the quality of the outputs of the networks to be similar to the reference even when using only 1 echo, with slight improvements when using more echoes. Training a network took at most 28.6 h. Inference time of a whole‐body scan took at most 3.7 s using the GPU and 5.8 min using the CPU.

    Conclusion: It is possible to perform water–fat signal separation of whole‐body gradient echo scans using convolutional neural networks. Separation was possible using only 1 echo, although using more echoes improved the results.

  • 227.
    Andersson, Jonathan
    et al.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Radiologi.
    Ahlström, Håkan
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Radiologi. Antaros Med, Molndal, Sweden.
    Kullberg, Joel
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Radiologi. Antaros Med, Molndal, Sweden.
    Water-fat separation incorporating spatial smoothing is robust to noise2018Inngår i: Magnetic Resonance Imaging, ISSN 0730-725X, E-ISSN 1873-5894, Vol. 50, s. 78-83, artikkel-id S0730-725X(18)30040-7Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    PURPOSE: To develop and evaluate a noise-robust method for reconstruction of water and fat images for spoiled gradient multi-echo sequences.

    METHODS: The proposed method performs water-fat separation by using a graph cut to minimize an energy function consisting of unary and binary terms. Spatial smoothing is incorporated to increase robustness to noise. The graph cut can fail to find a solution covering the entire image, in which case the relative weighting of the unary term is iteratively increased until a complete solution is found. The proposed method was compared to two previously published methods. Reconstructions were performed on 16 cases taken from the 2012 ISMRM water-fat reconstruction challenge dataset, for which reference reconstructions were provided. Robustness towards noise was evaluated by reconstructing images with different levels of noise added. The percentage of water-fat swaps were calculated to measure performance.

    RESULTS: At low noise levels the proposed method produced similar results to one of the previously published methods, while outperforming the other. The proposed method significantly outperformed both of the previously published methods at moderate and high noise levels.

    CONCLUSION: By incorporating spatial smoothing, an increased robustness towards noise is achieved when performing water-fat reconstruction of spoiled gradient multi-echo sequences.

  • 228.
    Andersson, Jonathan
    et al.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Radiologi.
    Lundström, Elin
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Radiologi.
    Engström, Mathias
    GE Healthcare.
    Lubberink, Mark
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Radiologi.
    Ahlström, Håkan
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Radiologi. Antaros Medical.
    Kullberg, Joel
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Radiologi. Antaros Medical.
    Estimating the cold-induced brown adipose tissue glucose uptake rate measured by 18F-FDG PET using infrared thermography and water-fat separated MRI2019Inngår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, artikkel-id 12358Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Brown adipose tissue (BAT) expends chemical energy to produce heat, which makes it a potential therapeutic target for combating metabolic dysfunction and overweight/obesity by increasing its metabolic activity. The most well-established method for measuring BAT metabolic activity is glucose uptake rate (GUR) measured using 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET). However, this is expensive and exposes the subjects to potentially harmful radiation. Cheaper and safer methods are warranted for large-scale or longitudinal studies. Potential alternatives include infrared thermography (IRT) and magnetic resonance imaging (MRI). The aim of this study was to evaluate and further develop these techniques. Twelve healthy adult subjects were studied. The BAT GUR was measured using 18F-FDG PET during individualized cooling. The temperatures of the supraclavicular fossae and a control region were measured using IRT during a simple cooling protocol. The fat fraction and effective transverse relaxation rate of BAT were measured using MRI without any cooling intervention. Simple and multiple linear regressions were employed to evaluate how well the MRI and IRT measurements could estimate the GUR. Results showed that both IRT and MRI measurements correlated with the GUR. This suggest that these measurements may be suitable for estimating the cold-induced BAT GUR in future studies.

  • 229.
    Andersson, Jonathan
    et al.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Radiologi.
    Roswall, Josefine
    Hallands Hosp Halmstad, Dept Pediat, Halmstad, Sweden;Univ Gothenburg, Sahlgrenska Acad, Inst Clin Sci, Dept Pediat, Gothenburg, Sweden.
    Kjellberg, Emma
    Univ Gothenburg, Sahlgrenska Acad, Inst Clin Sci, Dept Pediat, Gothenburg, Sweden.
    Ahlström, Håkan
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Radiologi. Antaros Med, Molndal, Sweden.
    Dahlgren, Jovanna
    Univ Gothenburg, Sahlgrenska Acad, Inst Clin Sci, Dept Pediat, Gothenburg, Sweden.
    Kullberg, Joel
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Radiologi. Antaros Med, Molndal, Sweden.
    MRI estimates of brown adipose tissue in children - Associations to adiposity, osteocalcin, and thigh muscle volume2019Inngår i: Magnetic Resonance Imaging, ISSN 0730-725X, E-ISSN 1873-5894, Vol. 58, s. 135-142Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Context: Brown adipose tissue is of metabolic interest. The tissue is however poorly explored in children.

    Methods: Sixty-three 7-year old subjects from the Swedish birth-cohort Halland Health and Growth Study were recruited. Care was taken to include both normal weight and overweight children, but the subjects were otherwise healthy. Only children born full term were included. Water-fat separated whole-body MRI scans, anthropometric measurements, and measurements of fasting glucose and levels of energy homeostasis related hormones, including the insulin-sensitizer osteocalcin, were performed. The fat fraction (FF) and effective transverse relaxation time (T-2(star)) of suspected brown adipose tissue in the cervical-supraclavicular-axillary fat depot (sBAT) and the FFs of abdominal visceral (VAT) and subcutaneous adipose tissue (SAT) were measured. Volumes of sBAT, abdominal VAT and SAT, and thigh muscle volumes were measured.

    Results: The FF in the sBAT depot was lower than in VAT and SAT for all children. In linear correlations including sex and age as explanatory variables, sBAT FF correlated positively with all measures of adiposity (p < 0.01), except for VAT FF and weight, positively with sBAT T-2* (p = 0.036), and negatively with osteocalcin (p = 0.017). When adding measures of adiposity as explanatory variables, sBAT FF also correlated negatively with thigh muscle volume (p < 0.01).

    Conclusions: Whole-body water-fat MRI of children allows for measurements of sBAT. The FF of sBAT was lower than that of VAT and SAT, indicating presence of BAT. Future studies could confirm whether the observed correlations corresponds to a hormonally active BAT.

  • 230. Andersson, Lennart
    et al.
    Droller, Michael J.
    Adolfsson, Jan
    Månsson, Wiking
    Kirkali, Ziya
    Boffetta, Paolo
    Montironi, Rodolfo
    Malmström, Per-Uno
    Uppsala universitet, Medicinska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper. Uppsala universitet, Medicinska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Urologkirurgi.
    Tribukait, Bernhard
    Grossman, H. Barton
    Chairmen's summary2008Inngår i: Scandinavian Journal of Urology and Nephrology, Supplementum, ISSN 0300-8886, E-ISSN 1651-2537, nr 218, s. 7-11Artikkel i tidsskrift (Fagfellevurdert)
  • 231.
    Andersson, LG
    et al.
    Uppsala universitet, Medicinska vetenskapsområdet, Medicinska fakulteten, Institutionen för medicinska vetenskaper.
    Jeppsson, A
    Bratteby, LE
    Uppsala universitet, Medicinska vetenskapsområdet, Medicinska fakulteten, Institutionen för medicinska vetenskaper.
    Ekroth, R
    Joachimsson, PO
    Institutionen för kirurgiska vetenskaper.
    van der Linden, J
    Institutionen för kirurgiska vetenskaper.
    Wesslen, O
    Renal function during cardiopulmonary bypass: influence of the calcium entry blocker felodipine.1996Inngår i: Anesth. Analg., Vol. 83, s. 34-Artikkel i tidsskrift (Fagfellevurdert)
  • 232.
    Andersson, M. Gunnar
    et al.
    Natl Vet Inst, Dept Chem Environm & Feed Hyg, SE-75189 Uppsala, Sweden.
    Pålsson, Ann-Sofie
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Rättsmedicin. Natl Board Forens Med, Dept Forens Med, Box 1024, SE-75140 Uppsala, Sweden.
    Sandler, Håkan
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Rättsmedicin. Natl Board Forens Med, Dept Forens Med, Box 1024, SE-75140 Uppsala, Sweden.
    Mostad, Petter
    Chalmers Univ Technol, Math Sci, Gothenburg, Sweden;Univ Gothenburg, Gothenburg, Sweden.
    Application of the Bayesian framework for forensic interpretation to casework involving postmortem interval estimates of decomposed human remains2019Inngår i: Forensic Science International, ISSN 0379-0738, E-ISSN 1872-6283, Vol. 301, s. 402-414Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We demonstrate how the Bayesian framework for forensic interpretation can be adapted for casework involving postmortem intervals (PMI) utilizing taphonomic data as well as how to overcome some of the limitations of current approaches for estimating and communicating uncertainty. A model is implemented for indoor cases based on partial body scores from three different anatomical regions as correlated functions of accumulated temperature (AT). The multivariate model enables estimation of PMI for human remains also when one or two local body scores are missing or undetermined, e.g. as a result of burns, scars or covered body parts. The model was trained using the expectation maximization algorithm, enabling us to account for uncertainty of PMI and/or ambient temperature in the training data. Alternative approaches reporting the results are presented, including the likelihood curve, likelihood ratios for competing hypotheses and posterior probability distributions and credibility intervals for PMI. The applicability or the approaches in different forensic scenarios is discussed.

  • 233. Andersson, Magnus V.
    et al.
    Andersson, Peter
    Bohe, Måns
    Börjesson, Lars
    Graf, Wilhelm
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Kolorektalkirurgi.
    Jeppsson, Bengt
    Törkvist, Leif
    Åkerlund, Jan-Erik
    Söderholm, Johan Dabrosin
    Kirurgi – omistligt komplement till medicinsk behandling2009Inngår i: Läkartidningen, ISSN 0023-7205, E-ISSN 1652-7518, Vol. 106, nr 45, s. 3003-9Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [sv]

    Kirurgi på rätt indikation och vid rätt tidpunkt är ett omistligt komplement till medicinsk behandling vid inflammatorisk tarmsjukdom, som förebygger sjukdomskomplikationer, förbättrar patienternas livskvalitet och ibland är livräddande. Kirurgi för ulcerös kolit görs oftast som ett tvåstegsförfarande: först kolektomi plus ileostomi med rektum lämnad intakt och i senare skede, med optimerad patient, tarmrekonstruktion anpassad efter patientens individuella livssituation. Kirurgi vid Crohns sjukdom korrigerar komplikationer (stenoser och fistlar) och sparar tarm genom begränsade resektioner och strikturplastiker. Laparoskopisk kir­urgi verkar ha viktiga fördelar vid primära tarmresektioner. Modern medicinsk behandling har förändrat indikationerna men ännu inte minskat behovet av kirurgi. Pågående antiinflammatorisk och immunmodulerande behandling är viktig att beakta i samband med kirurgi. Ett nära samspel mellan gastroenterolog och kolorektalkirurg är nödvändigt för att uppnå bästa möjliga långtidsprognos för de individer som lever med IBD.

  • 234. Andersson, Paul A
    et al.
    Jonsson, Halldór
    Uppsala universitet, Medicinska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper.
    Rauschning, Wolfgang
    Uppsala universitet, Medicinska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper.
    King, Hubert A
    Traumatic Rupture of the Transverse Ligament of the Atlas Associated with Occipito-Cervical Instability.1995Inngår i: J Orthop Trauma, Vol. 9, s. 312-Artikkel i tidsskrift (Fagfellevurdert)
  • 235.
    Andersson, Robin
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för cell- och molekylärbiologi, Centrum för bioinformatik.
    Bruder, Carl E G
    Piotrowski, Arkadiusz
    Menzel, Uwe
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för genetik och patologi.
    Nord, Helena
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för genetik och patologi.
    Sandgren, Johanna
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper.
    Hvidsten, Torgeir R
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för cell- och molekylärbiologi, Centrum för bioinformatik.
    de Ståhl, Teresita Diaz
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för genetik och patologi.
    Dumanski, Jan P
    Komorowski, Jan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för cell- och molekylärbiologi, Centrum för bioinformatik.
    A Segmental Maximum A Posteriori Approach to Genome-wide Copy Number Profiling2008Inngår i: Bioinformatics, ISSN 1367-4803, E-ISSN 1367-4811, Vol. 24, nr 6, s. 751-758Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    MOTIVATION: Copy number profiling methods aim at assigning DNA copy numbers to chromosomal regions using measurements from microarray-based comparative genomic hybridizations. Among the proposed methods to this end, Hidden Markov Model (HMM)-based approaches seem promising since DNA copy number transitions are naturally captured in the model. Current discrete-index HMM-based approaches do not, however, take into account heterogeneous information regarding the genomic overlap between clones. Moreover, the majority of existing methods are restricted to chromosome-wise analysis. RESULTS: We introduce a novel Segmental Maximum A Posteriori approach, SMAP, for DNA copy number profiling. Our method is based on discrete-index Hidden Markov Modeling and incorporates genomic distance and overlap between clones. We exploit a priori information through user-controllable parameterization that enables the identification of copy number deviations of various lengths and amplitudes. The model parameters may be inferred at a genome-wide scale to avoid overfitting of model parameters often resulting from chromosome-wise model inference. We report superior performances of SMAP on synthetic data when compared with two recent methods. When applied on our new experimental data, SMAP readily recognizes already known genetic aberrations including both large-scale regions with aberrant DNA copy number and changes affecting only single features on the array. We highlight the differences between the prediction of SMAP and the compared methods and show that SMAP accurately determines copy number changes and benefits from overlap consideration.

  • 236. Andersson, Roland
    et al.
    Hellman, Per
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Endokrinkirurgi. Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Experimentell kirurgi.
    Johansson, Jan
    Lagergren, Jesper
    Martling, Anna
    Naredi, Peter
    Nilsson, Magnus
    Sund, Malin
    Selektiv nivåstrukturering av svensk kirurgi behövs.2018Inngår i: Läkartidningen, ISSN 0023-7205, E-ISSN 1652-7518, Vol. 115, artikkel-id E76EArtikkel i tidsskrift (Fagfellevurdert)
  • 237. Andersson, S
    et al.
    Rylander, E
    Larsson, B
    Strand , A
    Uppsala universitet, Medicinska vetenskapsområdet, Medicinska fakulteten, Institutionen för medicinska vetenskaper.
    Silfversvärd, C
    Institutionen för kirurgiska vetenskaper.
    Wilander, E
    Institutionen för genetik och patologi.
    The role of human papillomavirus in cervical adenocarcinoma carcinogenesis.2001Inngår i: Eur J Cancer , Vol. 37, s. 246-Artikkel i tidsskrift (Fagfellevurdert)
  • 238.
    Andersson, Susanna
    et al.
    Uppsala universitet, Medicinska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper.
    Rodriques, Miriam
    Institutionen för onkologi, radiologi och klinisk immunologi.
    Olerud, Claes
    Uppsala universitet, Medicinska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper.
    Odontoid fractures: high complication rate associated with anterior screw fixation in the elderly2000Inngår i: Eur Spine J, Vol. 9, s. 56-Artikkel i tidsskrift (Fagfellevurdert)
  • 239.
    Andersson, Yvette
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper.
    Sentinel Node in Clinical Practice: Implications for Breast Cancer Treatment and Prognosis2012Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The introduction of sentinel lymph node biopsy (SLNB) has conveyed several new issues, such as the risk of false negativity, long-term consequences, the prognostic significance of micrometastases and whether ALND can be omitted in sentinel lymph node- (SLN) positive patients.

    Archived SLN specimens from 50 false negative patients and 107 true negative controls were serially sectioned and stained with immunohistochemistry. The detection rate of previously unknown metastases did not differ between the false and the true negative patients. The risk of false negativity was higher in patients with multifocal or hormone receptor-negative tumours, or if only one SLN was found.

    In a Swedish multicentre cohort, 2216 SLN-negative patients in whom ALND was omitted were followed up for a median of 65 months. The isolated axillary recurrence rate was only 1.0%, and the overall survival was hig