Medical Imaging Centre of Southwest Finland, Turku University Hospital, PO Box 52, 20521, Turku, Finland.
Neuroradiology. 2012 Aug;54(8):823-8. doi: 10.1007/s00234-011-0994-4. Epub 2011 Dec 13.
A positive correlation has been observed between multiple sclerosis (MS) disease activity status and the apparent diffusion coefficient (ADC) of the brain. Moreover, the relapse frequency of MS has been reported to decrease during pregnancy and increase postpartum. The aim of this study was to evaluate whether ADC histograms correlate with MS activity during pregnancy and postpartum, with a leading hypothesis that the ADC would increase postpartum compared to pregnancy.
Magnetic resonance imaging, as well as diffusion-weighted imaging, was performed in 19 patients with relapsing-remitting MS once during the third trimester and once 4-12 weeks postpartum. Brain tissue was extracted from nonbrain tissue with an automated computer program, and whole-brain histograms were generated. New or growing T2 lesions in postpartum images were counted on T2-weighted images.
In conventional brain magnetic resonance imaging, a significant increase in T2-lesion load was seen in postpartum images; 58% of patients showed signs of disease activity on their postpartum scan. Despite of this, and contrary to the original hypothesis, whole-brain ADC values were significantly lower in the postpartum period compared to the time of pregnancy.
This is the first study to address the ADC of the brain during pregnancy and postpartum period. We hypothesize that the higher ADC values observed during pregnancy in this study reflect the physiological status of the cerebral vasculature during pregnancy (generalized vasodilatation of downstream resistance arterioles and an increase of endothelial permeability), which overwhelm the alterations in ADC values normally seen related to MS activity.
多发性硬化症（MS）疾病活动状态与脑的表观扩散系数（ADC）之间存在正相关关系。此外，据报道 MS 的复发频率在怀孕期间会降低，产后会增加。本研究旨在评估 ADC 直方图是否与怀孕期间和产后的 MS 活动相关，主要假设是产后 ADC 会比怀孕期间增加。
19 例复发缓解型 MS 患者在妊娠晚期进行了一次磁共振成像（MRI），以及一次扩散加权成像（DWI），并在产后 4-12 周进行了一次检查。利用自动计算机程序从非脑组织中提取脑组织，并生成全脑直方图。在 T2 加权图像上计算产后图像中新出现或生长的 T2 病变。
在常规脑 MRI 中，产后图像中的 T2 病变负荷显著增加；58%的患者在产后扫描中出现疾病活动迹象。尽管如此，与原始假设相反，与怀孕期间相比，产后全脑 ADC 值显著降低。
这是第一项研究怀孕期间和产后大脑 ADC 的研究。我们假设，在这项研究中怀孕期间观察到的较高 ADC 值反映了怀孕期间脑血管的生理状态（下游阻力小动脉的普遍扩张和内皮通透性增加），这超过了与 MS 活动相关的 ADC 值变化。
