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Publications (10 of 37) Show all publications
Haller, S., Vernooij, M. W., Kuijer, J. P., Larsson, E.-M., Jäger, H. R. & Barkhof, F. (2018). Cerebral Microbleeds: Imaging and Clinical Significance. Radiology, 287(1), 11-28
Open this publication in new window or tab >>Cerebral Microbleeds: Imaging and Clinical Significance
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2018 (English)In: Radiology, ISSN 0033-8419, E-ISSN 1527-1315, Vol. 287, no 1, p. 11-28Article, review/survey (Refereed) Published
Abstract [en]

Cerebral microbleeds (CMBs), also referred to as microhemorrhages, appear on magnetic resonance (MR) images as hypointense foci notably at T2*-weighted or susceptibility-weighted (SW) imaging. CMBs are detected with increasing frequency because of the more widespread use of high magnetic field strength and of newer dedicated MR imaging techniques such as three-dimensional gradient-echo T2*-weighted and SW imaging. The imaging appearance of CMBs is mainly because of changes in local magnetic susceptibility and reflects the pathologic iron accumulation, most often in perivascular macrophages, because of vasculopathy. CMBs are depicted with a true-positive rate of 48%–89% at 1.5 T or 3.0 T and T2*-weighted or SW imaging across a wide range of diseases. False-positive “mimics” of CMBs occur at a rate of 11%–24% and include microdissections, microaneurysms, and microcalcifications; the latter can be differentiated by using phase images. Compared with postmortem histopathologic analysis, at least half of CMBs are missed with premortem clinical MR imaging. In general, CMB detection rate increases with field strength, with the use of three-dimensional sequences, and with postprocessing methods that use local perturbations of the MR phase to enhance T2* contrast. Because of the more widespread availability of high-field-strength MR imaging systems and growing use of SW imaging, CMBs are increasingly recognized in normal aging, and are even more common in various disorders such as Alzheimer dementia, cerebral amyloid angiopathy, stroke, and trauma. Rare causes include endocarditis, cerebral autosomal dominant arteriopathy with subcortical infarcts, leukoencephalopathy, and radiation therapy. The presence of CMBs in patients with stroke is increasingly recognized as a marker of worse outcome. Finally, guidelines for adjustment of anticoagulant therapy in patients with CMBs are under development.

National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:uu:diva-346992 (URN)10.1148/radiol.2018170803 (DOI)000427992600003 ()29558307 (PubMedID)
Available from: 2018-03-23 Created: 2018-03-23 Last updated: 2018-07-19Bibliographically approved
Haller, S., Burke, M. & Mueller, T. L. (2018). MR skin signal loss effect/artifact. Neuroradiology, 60(6), 661-662
Open this publication in new window or tab >>MR skin signal loss effect/artifact
2018 (English)In: Neuroradiology, ISSN 0028-3940, E-ISSN 1432-1920, Vol. 60, no 6, p. 661-662Article in journal, Editorial material (Refereed) Published
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:uu:diva-349496 (URN)10.1007/s00234-018-2025-1 (DOI)000432292400010 ()29682697 (PubMedID)
Available from: 2018-04-27 Created: 2018-04-27 Last updated: 2018-08-28Bibliographically approved
Georgiopoulos, C., Witt, S. T., Haller, S., Dizdar, N., Zachrisson, H., Engström, M. & Larsson, E.-M. (2018). Olfactory fMRI: implications of stimulation length and repetition time. Chemical Senses, 43(6), 389-398
Open this publication in new window or tab >>Olfactory fMRI: implications of stimulation length and repetition time
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2018 (English)In: Chemical Senses, ISSN 0379-864X, E-ISSN 1464-3553, Vol. 43, no 6, p. 389-398Article in journal (Refereed) Published
Abstract [en]

Studying olfaction with functional Magnetic Resonance imaging (fMRI) poses various methodological challenges. This study aimed to investigate the effects of stimulation length and repetition time (TR) on the activation pattern of four olfactory brain regions: the anterior and the posterior piriform cortex, the orbitofrontal cortex and the insula. 22 healthy participants with normal olfaction were examined with fMRI, with two stimulation lengths (6 seconds and 15 seconds) and two TRs (0.901 seconds and 1.34 seconds). Data were analyzed using General Linear Model (GLM), Tensorial Independent Component Analysis (TICA) and by plotting the event related time course of brain activation in the four olfactory regions of interest. The statistical analysis of the time courses revealed that short TR was associated with more pronounced signal increase and short stimulation was associated with shorter time to peak signal. Additionally, both long stimulation and short TR were associated with oscillatory time courses, whereas both short stimulation and short TR resulted in more typical time courses. GLM analysis showed that the combination of short stimulation and short TR could result in visually larger activation within these olfactory areas. TICA validated that the tested paradigm was spatially and temporally associated with a functionally connected network that included all four olfactory regions. In conclusion, the combination of short stimulation and short TR is associated with higher signal increase and shorter time to peak, making it more amenable to standard GLM-type analyses than long stimulation and long TR, and it should, thus, be preferable for olfactory fMRI.

National Category
Radiology, Nuclear Medicine and Medical Imaging Neurosciences
Identifiers
urn:nbn:se:uu:diva-350749 (URN)10.1093/chemse/bjy025 (DOI)000438293600001 ()29726890 (PubMedID)
Funder
Region Östergötland
Available from: 2018-05-15 Created: 2018-05-15 Last updated: 2018-09-27Bibliographically approved
Haller, S. & Barkhof, F. (2018). Peri-hippocampal developmental venous anomalies and memory loss: more than a normal variant? [Letter to the editor]. Neuroradiology, 60(6), 579-582
Open this publication in new window or tab >>Peri-hippocampal developmental venous anomalies and memory loss: more than a normal variant?
2018 (English)In: Neuroradiology, ISSN 0028-3940, E-ISSN 1432-1920, Vol. 60, no 6, p. 579-582Article in journal, Letter (Refereed) Published
National Category
Radiology, Nuclear Medicine and Medical Imaging Neurology
Identifiers
urn:nbn:se:uu:diva-350040 (URN)10.1007/s00234-018-2026-0 (DOI)000432292400001 ()29700565 (PubMedID)
Available from: 2018-05-03 Created: 2018-05-03 Last updated: 2018-08-28Bibliographically approved
Haller, S. (2018). Use of MR Imaging-defined Connectome to Predict the Recovery of Patients after Cardiac Arrest.. Radiology, 287(1), 256-257
Open this publication in new window or tab >>Use of MR Imaging-defined Connectome to Predict the Recovery of Patients after Cardiac Arrest.
2018 (English)In: Radiology, ISSN 0033-8419, E-ISSN 1527-1315, Vol. 287, no 1, p. 256-257Article in journal (Refereed) Published
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:uu:diva-346991 (URN)10.1148/radiol.2017172372 (DOI)000427992600031 ()29558302 (PubMedID)
Available from: 2018-03-23 Created: 2018-03-23 Last updated: 2018-07-19Bibliographically approved
Emmert, K., Breimhorst, M., Bauermann, T., Birklein, F., Rebhorn, C., Van De Ville, D. & Haller, S. (2017). Active pain coping is associated with the response in real-time fMRI neurofeedback during pain. Brain Imaging and Behavior, 11(3), 712-721
Open this publication in new window or tab >>Active pain coping is associated with the response in real-time fMRI neurofeedback during pain
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2017 (English)In: Brain Imaging and Behavior, ISSN 1931-7557, E-ISSN 1931-7565, Vol. 11, no 3, p. 712-721Article in journal (Refereed) Published
Abstract [en]

Real-time functional magnetic resonance imaging (rt-fMRI) neurofeedback is used as a tool to gain voluntary control of activity in various brain regions. Little emphasis has been put on the influence of cognitive and personality traits on neurofeedback efficacy and baseline activity. Here, we assessed the effect of individual pain coping on rt-fMRI neurofeedback during heat-induced pain. Twenty-eight healthy subjects completed the Coping Strategies Questionnaire (CSQ) prior to scanning. The first part of the fMRI experiment identified target regions using painful heat stimulation. Then, subjects were asked to down-regulate the pain target brain region during four neurofeedback runs with painful heat stimulation. Functional MRI analysis included correlation analysis between fMRI activation and pain ratings as well as CSQ ratings. At the behavioral level, the active pain coping (first principal component of CSQ) was correlated with pain ratings during neurofeedback. Concerning neuroimaging, pain sensitive regions were negatively correlated with pain coping. During neurofeedback, the pain coping was positively correlated with activation in the anterior cingulate cortex, prefrontal cortex, hippocampus and visual cortex. Thermode temperature was negatively correlated with anterior insula and dorsolateral prefrontal cortex activation. In conclusion, self-reported pain coping mechanisms and pain sensitivity are a source of variance during rt-fMRI neurofeedback possibly explaining variations in regulation success. In particular, active coping seems to be associated with successful pain regulation.

Keywords
Real-time fMRI, Neurofeedback, fMRI, Pain, Pain coping, CSQ
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:uu:diva-312309 (URN)10.1007/s11682-016-9547-0 (DOI)000403676400010 ()27071949 (PubMedID)
Available from: 2017-01-09 Created: 2017-01-09 Last updated: 2017-10-26Bibliographically approved
Haller, S. (2017). Advance MR imaging in sports-related concussion and mild traumatic brain injury: ready for clinical use? (Commentary on Tremblay et al. 2017). European Journal of Neuroscience, 46(4), 1954-1955
Open this publication in new window or tab >>Advance MR imaging in sports-related concussion and mild traumatic brain injury: ready for clinical use? (Commentary on Tremblay et al. 2017)
2017 (English)In: European Journal of Neuroscience, ISSN 0953-816X, E-ISSN 1460-9568, Vol. 46, no 4, p. 1954-1955Article in journal, Editorial material (Other academic) Published
National Category
Neurology
Identifiers
urn:nbn:se:uu:diva-336183 (URN)10.1111/ejn.13643 (DOI)000407639000002 ()28699247 (PubMedID)
Available from: 2017-12-12 Created: 2017-12-12 Last updated: 2018-03-13Bibliographically approved
Haller, S., Montandon, M.-L. -., Rodriguez, C., Ackermann, M., Herrmann, F. R. & Giannakopoulos, P. (2017). APOE*E4 Is Associated with Gray Matter Loss in the Posterior Cingulate Cortex in Healthy Elderly Controls Subsequently Developing Subtle Cognitive Decline. American Journal of Neuroradiology, 38(7), 1335-1342
Open this publication in new window or tab >>APOE*E4 Is Associated with Gray Matter Loss in the Posterior Cingulate Cortex in Healthy Elderly Controls Subsequently Developing Subtle Cognitive Decline
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2017 (English)In: American Journal of Neuroradiology, ISSN 0195-6108, E-ISSN 1936-959X, Vol. 38, no 7, p. 1335-1342Article in journal (Refereed) Published
Abstract [en]

BACKGROUND AND PURPOSE: The presence of apolipoprotein E4 (APOE*E4) is the strongest currently known genetic risk factor for Alzheimer disease and is associated with brain gray matter loss, notably in areas involved in Alzheimer disease pathology. Our objective was to assess the effect of APOE*E4 on brain structures in healthy elderly controls who subsequently developed subtle cognitive decline.

MATERIALS AND METHODS: This prospective study included 382 community-dwelling elderly controls. At baseline, participants underwent MR imaging at 3T, extensive neuropsychological testing, and genotyping. After neuropsychological follow-up at 18 months, participants were classified into cognitively stable controls and cognitively deteriorating controls. Data analysis included whole-brain voxel-based morphometry and ROI analysis of GM.

RESULTS: APOE*E4-related GM loss at baseline was found only in the cognitively deteriorating controls in the posterior cingulate cortex. There was no APOE*E4-related effect in the hippocampus, mesial temporal lobe, or brain areas not involved in Alzheimer disease pathology. Controls in the cognitively deteriorating group had slightly lower GM concentration in the hippocampus at baseline. Higher GM densities in the hippocampus, middle temporal lobe, and amygdala were associated with a decreased risk for cognitively deteriorating group status at follow-up.

CONCLUSIONS: APOE*E4-related GM loss in the posterior cingulate cortex (an area involved in Alzheimer disease pathology) was found only in those elderly controls who subsequently developed subtle cognitive decline but not in cognitively stable controls. This finding might explain the partially conflicting results of previous studies that typically did not include detailed neuropsychological assessment and follow-up. Most important, APOE*E4 status had no impact on GM density in areas affected early by neurofibrillary tangle formation such as the hippocampus and mesial temporal lobe.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-332199 (URN)10.3174/ajnr.A5184 (DOI)000405565100013 ()28495939 (PubMedID)
Available from: 2017-10-26 Created: 2017-10-26 Last updated: 2017-10-31Bibliographically approved
Fällmar, D., Haller, S., Lilja, J., Danfors, T., Kilander, L., Tolboom, N., . . . Larsson, E.-M. (2017). Arterial spin labeling-based Z-maps have high specificity and positive predictive value for neurodegenerative dementia compared to FDG-PET.. European Radiology, 27(10), 4237-4246
Open this publication in new window or tab >>Arterial spin labeling-based Z-maps have high specificity and positive predictive value for neurodegenerative dementia compared to FDG-PET.
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2017 (English)In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 27, no 10, p. 4237-4246Article in journal (Refereed) Published
Abstract [en]

OBJECTIVE: Cerebral perfusion analysis based on arterial spin labeling (ASL) MRI has been proposed as an alternative to FDG-PET in patients with neurodegenerative disease. Z-maps show normal distribution values relating an image to a database of controls. They are routinely used for FDG-PET to demonstrate disease-specific patterns of hypometabolism at the individual level. This study aimed to compare the performance of Z-maps based on ASL to FDG-PET.

METHODS: Data were combined from two separate sites, each cohort consisting of patients with Alzheimer's disease (n = 18 + 7), frontotemporal dementia (n = 12 + 8) and controls (n = 9 + 29). Subjects underwent pseudocontinuous ASL and FDG-PET. Z-maps were created for each subject and modality. Four experienced physicians visually assessed the 166 Z-maps in random order, blinded to modality and diagnosis.

RESULTS: Discrimination of patients versus controls using ASL-based Z-maps yielded high specificity (84%) and positive predictive value (80%), but significantly lower sensitivity compared to FDG-PET-based Z-maps (53% vs. 96%, p < 0.001). Among true-positive cases, correct diagnoses were made in 76% (ASL) and 84% (FDG-PET) (p = 0.168).

CONCLUSION: ASL-based Z-maps can be used for visual assessment of neurodegenerative dementia with high specificity and positive predictive value, but with inferior sensitivity compared to FDG-PET.

KEY POINTS: • ASL-based Z-maps yielded high specificity and positive predictive value in neurodegenerative dementia. • ASL-based Z-maps had significantly lower sensitivity compared to FDG-PET-based Z-maps. • FDG-PET might be reserved for ASL-negative cases where clinical suspicion persists. • Findings were similar at two study sites.

Keywords
18F-FDG, Arterial spin labeling MRI, Dementia, Neurodegenerative, Visual assessment
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-319602 (URN)10.1007/s00330-017-4784-1 (DOI)000408952400027 ()28374078 (PubMedID)
Available from: 2017-04-06 Created: 2017-04-06 Last updated: 2018-01-03Bibliographically approved
Zanchi, D., Cunningham, G., Ladermann, A., Ozturk, M., Hoffmeyer, P. & Haller, S. (2017). Brain activity in the right-frontal pole and lateral occipital cortex predicts successful post-operatory outcome after surgery for anterior glenoumeral instability. Scientific Reports, 7, Article ID 498.
Open this publication in new window or tab >>Brain activity in the right-frontal pole and lateral occipital cortex predicts successful post-operatory outcome after surgery for anterior glenoumeral instability
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2017 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, article id 498Article in journal (Refereed) Published
Abstract [en]

Shoulder apprehension is more complex than a pure mechanical problem of the shoulder, creating a scar at the brain level that prevents the performance of specific movements. Surgery corrects for shoulder instability at the physical level, but a re-dislocation within the first year is rather common. Predicting which patient will be likely to have re-dislocation is therefore crucial. We hypothesized that the assessment of neural activity at baseline and follow-up is the key factor to predict the postoperatory outcome. 13 patients with shoulder apprehension (30.03 +/- 7.64 years) underwent clinical and fMRI examination before and one year after surgery for shoulder dislocation contrasting apprehension cue videos and control videos. Data analyses included task-related general linear model (GLM) and correlations imaging results with clinical scores. Clinical examination showed decreased pain and increased shoulder functions for post-op vs. pre-op. Coherently, GLM results show decreased activation of the left pre-motor cortex for post-surgery vs. pre-surgery. Right-frontal pole and right-occipital cortex activity predicts good recovery of shoulder function measured by STT. Our findings demonstrate that beside physical changes, changes at the brain level also occur one year after surgery. In particular, decreased activity in pre-motor and orbito-frontal cortex is key factor for a successful post-operatory outcome.

Place, publisher, year, edition, pages
NATURE PUBLISHING GROUP, 2017
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:uu:diva-320037 (URN)10.1038/s41598-017-00518-9 (DOI)000397729900004 ()28356560 (PubMedID)
Available from: 2017-04-13 Created: 2017-04-13 Last updated: 2017-11-29Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-7433-0203

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