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BACKGROUND: Eclampsia, a serious pregnancy complication, is associated with cerebral edema and infarctions but the underlying pathophysiology remains largely unexplored.

OBJECTIVES: To assess the pathophysiology of eclampsia using specialized magnetic resonance imaging that measures diffusion, perfusion, and vasospasm.

STUDY DESIGN: This was a cross-sectional study recruiting consecutive pregnant women between April 2018 to November 2021 at Tygerberg Hospital, Cape Town, South Africa. We recruited women with eclampsia, preeclampsia, and normotensive pregnancies who underwent magnetic resonance imaging after birth. Main outcome measures were cerebral infarcts, edema, and perfusion using intravoxel incoherent motion imaging and vasospasm using magnetic resonance imaging angiography. The imaging protocol was established before inclusion.

RESULTS: Forty-nine women with eclampsia, 20 with preeclampsia and 10 normotensive women were included. Cerebral infarcts were identified in 34% of eclamptic, 5% of preeclamptic (risk difference (RD) 0.29; 95% confidence interval (CI) 0.06 to 0.52, p=0.012) and in no normotensive controls. Eclamptic women were more likely to have vasogenic cerebral edema compared to preeclamptic (80% vs 20%, RD 0.60; CI 0.34 to 0.85, p<.001) and normotensive women (RD 0.80; CI 0.47 to 1.00, p<.001). Diffusion was increased in eclampsia in the parietooccipital white matter (mean difference (MD) 0.02 x10^-3 mm²/s, CI 0.00 to 0.05, p=0.045) and the caudate nucleus (MD 0.02 x10^-3 mm²/s, CI 0.00 to 0.04, p=0.033) when compared to preeclamptic women. Diffusion was also increased in eclamptic women in the frontal (MD 0.07 x10^-3 mm²/s, CI 0.02 to 0.12, p=0.012) and parietooccipital white matter (MD 0.05 x10^-3 mm²/s, CI 0.02 to 0.07, p=0.03) and the caudate nucleus (MD 0.04 x10^-3 mm²/s, CI 0.00 to 0.07, p=0.028) when compared to normotensive women. Perfusion was decreased in edematous regions. Hypoperfusion was present in the caudate nucleus in eclampsia (MD -0.17 x10^-3 mm²/s, CI -0.27 to -0.06, p=0.003) when compared to preeclampsia. There were no signs of hyperperfusion. Vasospasm was present in 18% of eclamptic, 6% of preeclamptic and none of the controls.

CONCLUSIONS: Eclampsia is associated with cerebral infarcts, vasogenic cerebral edema, vasospasm and decreased perfusion, all not usually evident on standard clinical imaging. This may explain why some have cerebral symptoms and signs despite having normal conventional imaging.

Objective The objective of this systematic literature review was to explore the value of positron emission tomography combined with low-dose computed tomography (18F-FDG-PET-CT) in the diagnostics of infective native aortic aneurysm (INAA). Methods A systematic literature review was performed using the search terms mycotic- and infected aortic aneurysms in Medline and Sciencedirect databases, published between 1 January 2000 and 1 January 2020. Using the PRISMA statement, articles were scrutinized according to a predefined protocol including: timing of 18F-FDG-PET-CT examination, the maximum standardized uptake value (SUVmax), additional findings on examination, and findings on repeated scanning of 18F-FDG-PET-CT. Results Four studies were included in the analysis, comprising a total of 11 patients. Two studies were single case reports, and two were small case series, all were graded to be of low quality with high risk of bias. All patients were examined with a preoperative 18F-FDG-PET-CT, and 10 (91%) had increased 18F-FDG uptakes. The median SUVmax value was 6.53, range 4.46-9.23. The mean duration of antibiotic therapy prior to 18F-FDG-PET-CT was not known. Two patients were examined with repeated 18F-FDG-PET-CT examinations after treatment, where a decrease in SUVmax values could be demonstrated after successful treatment. Conclusion The literature on 18F-FDF-PET/CT for diagnosing infective native aortic aneurysms is scarce. However, there might be a role for 18F-FDF-PET/CT in the management of the disease, in particular for patients with clinical suspicion of INAA without convincing findings on CT. SUVmax values ranging from 4.5 to 6.5 could be guiding and suggestive of metabolic activity in agreement of INAA. However, further conclusions on its usefulness, robustness and specific SUVmax values are premature, and a definitive cut-off value is probably not attainable.

Background

Cerebral complications are the main reasons for morbidity and mortality in preeclampsia and eclampsia. Still we do not know if the pathophysiology entails hypo- or hyperperfusion of the brain, or how and when edema emerges, due to the difficulty to examine the cerebral circulation.

Material and methods

We have used a non-invasive diffusion weighted magnetic resonance imaging (MRI) technique, intravoxel incoherent motion, to study cerebral perfusion on the capillary level and cerebral edema in women with preeclampsia (n=30), normal pregnancy (n=32) and non-pregnant women (n=16). Estimates of cerebral blood volume, blood flow and edema were measured in five different regions. These points were chosen to represent blood supply areas of both the carotid and vertebrobasilar arteries, and to include both white and grey matter.

Results

Except for the caudate nucleus, we did not detect any differences in cerebral perfusion measures on a group level. In the caudate nucleus we found lower cerebral blood volume  and lower blood flow in preeclampsia compared to both normal pregnancy (p=0.01 and p=0.03, respectively) and non-pregnant women (both p=0.02). No differences in edema were detected between study groups.

Conclusion

The cerebral perfusion measures were comparable between the study groups, except for a portion of the basal ganglia where hypoperfusion was detected in preeclampsia compared to normal pregnancy and non-pregnant women.