Focal status epilepticus: follow-up by perfusion- and diffusion MRI

Diffusion-weighted MRI demonstrated bright right temporoparietal cortex, right hippocampus, and left cerebellum in a 63-year-old female suffering a focal convulsive status epilepticus. Hyperperfusion was noted in the right temporoparietal region. Two days later, a tendency to normalization of most of the diffusion and perfusion changes was noted, apart from the right hippocampus which became brighter on diffusion- and T2-weighted images. On the tenth day the apparent diffusion coefficient was slightly elevated, getting brighter on T2-weighted images with suspected mild post-contrast enhancement. We postulate that the discharging right hippocampus suffered cytotoxic edema, which later progressed to cell damage.     

Reversible changes in echo planar perfusion- and diffusion-weighted MRI in status epilepticus

Perfusion imaging (PI) demonstrated increased perfusion and diffusion-weighted imaging (DWI) showed high signal limited to the left temporoparietal cortex in a 68-year-old man with nonconvulsive status epilepticus. The EEG showed a slow delta-wave focus. The patient recovered and PI, DWI and EEG changes completely resolved. Received: 2 July 1999/Accepted: 13 July 1999     

癫痫持续状态严重程度评分量表判断癫痫持续状态患者生存情况Meta分析

目的探讨癫痫持续状态严重程度评分量表(STESS)判断癫痫持续状态(SE)患者生存情况的临床应用价值。方法检索Pub Med、EMBASE、中国生物医学文献数据库(CBM)、中文期刊全文数据库(CNKI),检索时间为2005年1月至2016年10月,收集关于STESS研究的相关文献。依据诊断试验文献质量评价标准(QUADAS)对纳入文献进行质量评价。采用Meta Disc 1.4和STATA 12.0软件进行Meta分析,计算合并灵敏度、特异度、诊断比值比(DOR)及95%可信区间,绘制合并受试者工作特征(SROC)曲线,计算曲线下面积(AUC),并进行亚组分析、敏感性分析及发表偏倚的评估。结果本研究共纳入8篇文献,包含9项研究,共计纳入1 029例患者。文献存在非阈值效应引起的异质性,采用随机效应模型计算STESS判断SE患者死亡的合并灵敏度和特异度分别为0.817(95%可信区间0.752～0.870)和0.527(95%可信区间0.492～0.561),其DOR为4.822(95%可信区间2.936～7.918);SROC-AUC为0.740。结论 STESS对于诊断SE患者生存情况具有中等度效能,可以作为重要参考,但仍需要更大样本更高质量研究验证。     

Crossed cerebellar diaschisis in the setting of a convulsive status epilepticus: a rare clinical and radiological entity

Crossed cerebellar diaschisis is a rare clinical entity of hemispheric cerebellar depression subsequent to a contralateral cerebral cortical lesion, described to be the result of excessive neuronal excitatory synaptic activity within cortico-cerebellar pathways. This event is generally observed in ischemic stroke cases, and only occasionally, it has been described in epileptic seizure disorders. In this report, we present the case of a patient admitted for status epilepticus with residual motor and visual deficit, with reduced diffusion at DWI. The clinical evolution of her case was distinguished by a full recovery of her deficits along with the disappearance of the MRI abnormalities.     

Changes in water diffusion and relaxation properties of rat cerebrum during status epilepticus

Diffusion-weighted (DW) imaging has been used to record changes associated with status epilepticus (SE) in rat brain. It was found that the apparent diffusion coefficient (ADC) of water in brain decreased14–18% during SE, and it fell a further 20–22% when the animals were sacrificed. The transverse decay time constant T₂ showed corresponding reductions, but no significant changes were seen in relaxation times T₁ or T₂ values. Changes in ADC in status epilepticus are similar to those seen in stroke and ischemia but occur under very differ ret conditions of blood flow and metabolism.     

Role of cranial imaging in epileptic status

Introduction

There is paucity of studies evaluating the role of cranial imaging in the management of status epilepticus (SE); therefore this study evaluates the role of imaging in predicting the outcome of SE.

Methods

Consecutive patients with SE were prospectively evaluated. Clinical evaluation, blood counts, serum chemistry and cerebrospinal fluid (CSF) were carried out. Cranial CT scan was performed on a spiral CT and MRI on a 1.5 T scanner. Patients were treated with IV sodium valproate, phenytoin and benzodiazepines as per fixed protocol. Outcome was defined as seizure control at 1 h and mortality. Various clinical and radiological parameters were correlated.

Results

There were 99 patients with SE whose mean age was 35 (1–78) years, 40 females and 17 were below 12 years of age. Fifty six patients had central nervous system (CNS) infections, 15 strokes, 13 metabolic encephalopathy, 5 drug default and in the remaining 10 patients various acute symptomatic causes were present. Cranial imaging was abnormal in 59% patients. CT was abnormal in 21 (47.7%) out of 44 patients whereas MRI was abnormal in 26 (63.4%) out of 41 patients. Both MRI and CT were carried out in 14 patients and 12 revealed abnormalities; 2 had abnormality only on MRI. Imaging revealed cortical lesions in 10, subcortical in 19 and both cortical as well as subcortical in 30 patients. One hour seizure control was achieved in 60, seizures recurred within 24 h in 38 and 27 patients died during hospital stay. Seizure type, duration of SE, seizure control at 1 h and mortality did not correlate with radiological abnormalities.

Conclusion

Cranial imaging reveals structural abnormality in 59% patients with SE and was not related to SE control and mortality.     

Transient MR signal changes in patients with generalized tonicoclonic seizure or status epilepticus: periictal diffusion-weighted imaging.

BACKGROUND AND PURPOSE: Our purpose was to investigate transient MR signal changes on periictal MR images of patients with generalized tonicoclonic seizure or status epilepticus and to evaluate the clinical significance of these findings for differential diagnosis and understanding of the pathophysiology of seizure-induced brain changes. METHODS: Eight patients with MR images that were obtained within 3 days after the onset of generalized tonicoclonic seizure or status epilepticus and that showed seizure-related MR signal changes had their records retrospectively reviewed. T1- and T2-weighted images were obtained of all eight patients. Additional diffusion-weighted images were obtained of five patients during initial examination. After adequate control of the seizure was achieved, follow-up MR imaging was performed. We evaluated the signal changes, location of the lesions, and degree of contrast enhancement on T1- and T2-weighted images and the signal change and apparent diffusion coefficient (ADC) on diffusion-weighted images. We also compared the signal changes of the initial MR images to those of the follow-up MR images. RESULTS: The initial MR images revealed focally increased T2 signal intensity, swelling, and increased volume of the involved cortical gyrus in all eight patients. The lesions were located in the cortical gray matter or subcortical white matter in seven patients and at the right hippocampus in one. T1-weighted images showed decreased signal intensity at exactly the same location (n = 6) and gyral contrast enhancement (n = 4). Diffusion-weighted images revealed increased signal intensity at the same location and focally reduced ADC. The ADC values were reduced by 6% to 28% compared with either the normal structure opposite the lesion or normal control. Follow-up MR imaging revealed the complete resolution of the abnormal T2 signal change and swelling in five patients, whereas resolution of the swelling with residual increased T2 signal intensity at the ipsilateral hippocampus was observed in the other two patients. For one of the two patients, hippocampal sclerosis was diagnosed. For the remaining one patient, newly developed increased T2 signal intensity was shown. CONCLUSION: The MR signal changes that occur after generalized tonicoclonic seizure or status epilepticus are transient increase of signal intensity and swelling at the cortical gray matter, subcortical white matter, or hippocampus on periictal T2-weighted and diffusion-weighted images. These findings reflect transient cytotoxic and vasogenic edema induced by seizure. The reversibility and typical location of lesions can help exclude the epileptogenic structural lesions.     

Pancreatic changes in patients with primary sclerosing cholangitis: MR cholangiopancreatography and MRI findings

Purpose

To evaluate the possible pancreatic changes and their frequencies in patients with primary sclerosing cholangitis (PSC) on MR cholangiopancreatography (MRCP), and conventional abdominal MRI.

Materials and Methods

Patient group consisted of 29 PSC (13 male, 16 female) cases, whereas cohort 1 consisted of 12 female patients with primary biliary cirrhosis, and cohort 2 consisted of 17 patients (6 male, 11 female) with non-immune chronic liver disease. Two radiologists retrospectively evaluated the MR examinations paying special attention to the pancreatic size (atrophy or enlargement), T1- and T2-signal intensity of the pancreas, focal pancreatic lesion, capsule-like rim, peripancreatic edema or fluid, fascial thickening, and pancreatic ducts (dilatation or narrowing). The results are expressed as percentages. Three groups were compared using Pearson chi-square test for each feature. However, only p-value for “dilatation of the pancreatic duct” was determined, whereas p-value could not be calculated because of the insufficient number of subjects/sequences for the other features.

Results

Twelve PSC patients (41.3%) had pancreatic abnormalities. The most common pancreatic changes in PSC patients were decreased T1-signal intensity (44%) and dilatation of the pancreatic duct (13.8%), respectively. Increased T2-signal intensity was also shown in 2 PSC patients (6.9%).

Conclusion

Even PSC patients without any sign of pancreatitis, can show MR changes in the pancreatic parenchyma or the pancreatic duct. The etiologies of these changes, and whether they are unique to PSC, are still controversial. Histopathological studies bringing light to these pancreatic changes are needed.     

Gray matter prefrontal changes in type 2 diabetes detected using MRI

PURPOSE: To examine the volumes of the gray and white matter both globally and regionally in patients diagnosed with type 2 diabetes and controls. MATERIALS AND METHODS: Our samples were comprised of 26 patients with type 2 diabetes, 26 patients with diabetes and major depressive disorder, and 25 nondiabetic, nondepressed control subjects. All subjects were studied cross-sectionally on a 1.5 T scanner and were recruited from medicine/diabetes clinics. Both gray and white matter volumes were estimated using an automated method, and the prefrontal areas studied included the anterior cingulate, the gyrus rectus, and the orbitofrontal regions. RESULTS: Patients with diabetes, both with and without depression, had smaller total brain gray matter volumes when compared with the control subjects after controlling for age, intracranial volume, and years of education. This group also had smaller gray matter volumes in the anterior cingulate and orbitofrontal regions when compared with the controls after additionally controlling for total gray matter volume. The depressed and nondepressed diabetic groups did not differ on any neuroimaging measure. Cerebrovascular risk factors correlated negatively with gray matter volumes. CONCLUSION: The findings indicate that type 2 diabetes is associated with specific neuroanatomical abnormalities in the prefrontal gray matter. Vascular disease might contribute to the findings observed in our sample. These observations have implications for the behavioral sequelae of diabetes.     

颈椎终板Modic退变在颈项痛患者中的MRI表现及相关因素分析

目的 探讨颈椎Modic退变在颈项痛患者MRI中的表现及相关因素.方法 选取本院2014年1月至2015年1月因颈项痛而就诊的患者512例,男186例,女326例,年龄15 ～ 85岁,平均54.8岁.所有患者均行颈椎MRI检查.回顾性分析颈椎Modic退变在颈项痛患者中节段、退变程度、颈椎曲度、性别、年龄中的分布特点,并分析与椎间盘突出的相关性.结果 512例患者3072个椎间盘中,59例(11.5％)93个椎间盘(3.0％)发生了Modic退变,其中Ⅰ型7个,Ⅱ型57个,Ⅲ型29个.C2～3、C3～4、C4～5、C5～6、C6～7、C7～T1发生Modic退变的发病率分别为0、0.36％、0.55％、1.20％、0.85％、0.07％.40岁以上是颈椎Modic退变的好发年龄. 结论 MRI是颈椎Modic退变的首要检查方法.颈椎Modic退变Ⅱ型最常见,最常发生在C5～6、C6～7节段.颈椎Modic退变的发生与椎间盘退变程度、颈椎曲度、年龄存在相关性,还与颈椎间盘突出具有相关性.     

Temporal dependence of in vivo USPIO-enhanced MRI signal changes in human carotid atheromatous plaques

Introduction  Ultrasmall superparamagnetic iron oxide (USPIO)-enhanced MRI has been shown to be a useful modality to image activated macrophages in vivo, which are principally responsible for plaque inflammation. This study determined the optimum imaging time-window to detect maximal signal change post-USPIO infusion using T₁-weighted (T₁w), T₂*-weighted (T₂*w) and quantitative T₂* (qT₂*) imaging. Methods  Six patients with an asymptomatic carotid stenosis underwent high resolution T₁w, T₂*w and qT₂* MR imaging of their carotid arteries at 1.5 T. Imaging was performed before and at 24, 36, 48, 72 and 96 h after USPIO (Sinerem™, Guerbet, France) infusion. Each slice showing atherosclerotic plaque was manually segmented into quadrants and signal changes in each quadrant were fitted to an exponential power function to model the optimum time for post-infusion imaging. Results  The power function determining the mean time to convergence for all patients was 46, 41 and 39 h for the T₁w, T₂*w and qT₂* sequences, respectively. When modelling each patient individually, 90% of the maximum signal intensity change was observed at 36 h for three, four and six patients on T₁w, T₂*w and qT₂*, respectively. The rates of signal change decrease after this period but signal change was still evident up to 96 h. Conclusion  This study showed that a suitable imaging window for T₁w, T₂*w and qT₂* signal changes post-USPIO infusion was between 36 and 48 h. Logistically, this would be convenient in bringing patients back for one post-contrast MRI, but validation is required in a larger cohort of patients. Sources of funding: GlaxoSmithKline and The Stroke Association     

Modeling neuronal current MRI signal with human neuron

Up to date, no consensus has been achieved regarding the possibility of detecting neuronal currents by MRI (ncMRI) in human brain. To evaluate the detectability of ncMRI, an effective way is to simulate ncMRI signal with the realistic neuronal geometry and electrophysiological processes. Unfortunately, previous realistic ncMRI models are based on rat and monkey neurons. The species difference in neuronal morphology and physiology would prevent these models from simulating the ncMRI signal accurately in human subjects. The aim of this study is to bridge this gap by establishing a realistic ncMRI model specifically for human cerebral cortex. In this model, the ncMRI signal was simulated using anatomically reconstructed human pyramidal neurons and their biophysical properties. The modeling results showed that the amplitude of ncMRI signal significantly depends on the density of synchronously firing neurons and imaging conditions such as position of imaging voxel, direction of main magnetic field (B₀) relative to the cortical surface and echo time. The results indicated that physiologically‐evoked ncMRI signal is too weak to be detected (magnitude/phase change ≤ ?1.4 × 10^?6/0.02°), but the phase signal induced by spontaneous activity may reach a detectable level (up to 0.2°) in favorable conditions. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.     

MRI signal changes in completely healed meniscus confirmed by second-look arthroscopy after meniscal repair with bioabsorbable arrows

This study evaluated the MRI signal characteristics and MRI diagnostic accuracy in identifying completely healed menisci repaired with bioabsorbable arrows. A total of 34 patients (38 menisci), with a mean age of 26.0 years, underwent arthroscopic meniscal repair with bioabsorbable arrows and concomitant anterior cruciate ligament (ACL) reconstruction. Of the 34 patients, 27 were male and 7 were female. Of the 38 menisci, 27 were medial and 11 were lateral. Second-look arthroscopy was performed for each patient while taking out the hardware for ACL reconstruction of the tibial side to evaluate the healing status of the repaired menisci. Postoperative MRI was done 2 days before or after second-look arthroscopy. Sagittal T1, T2 and PD images and coronal T2 and PD images were used as the main diagnostic serials. Second-look arthroscopy showed that surfaces of the repaired sites of all 38 menici were almost smooth. In all 38 cases the tail ends of meniscus arrows disappeared and in four patients new overlying injury of compartmental cartilage at the repaired side was detected. MRI results revealed that different serials had different diagnostic accuracy. Sagittal: T1 28.9%, PD 34.2%, T2 60.5%. Coronal: PD 36.8%, T2 65.8%. The double sides Grade 3 signal had a higher proportion in saggital T1 and PD serials, 47.4 and 39.5%, respectively, while lower in sagittal and coronal T2 serials, both 5.3%. MRI diagnostic accuracy was correlated positively with the follow-up time (P < 0.05). MRI has its limitation in evaluating the status of menisci repaired with bioabsorbable arrows, especially for PD and T1 serials. T2 serials have higher diagnostic accuracy than other serials. MRI diagnostic accuracy can be improved by prolonging follow-up time and might be improved by further classifying Grade 3 signal in terms of signal intensity and the shape of the signal margin. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

原发性三叉神经痛形态学及功能改变的MRI研究现状与进展

原发性三叉神经痛(PTN)是以三叉神经分布区发作性剧痛为临床特征的常见颅神经疾病,其病因尚未清楚。三维稳态采集快速成像(3D-FIESTA)序列可以观察神经以及周围结构的形态学变化,为PTN提供病因学依据。扩散张量成像(DTI)可以量化评价髓鞘情况,为PTN提供功能学依据。3D-FIESTA联合DTI序列对全面理解PTN的发病机制、功能变化、评估预后等具有重要意义。对MRI在PTN病人形态学及功能改变中的研究现状与进展作一综述。     

MRI in haemochromatosis: pituitary versus testicular iron deposition in five patients with hypogonadism

Haemochromatosis is a disease characterised by iron deposition in the liver and other organs. Hypogonadism is a commonly associated condition and may be either primary due to testicular lesions or secondary due to pituitary dysfunction. Hypogonadism secondary to pituitary dysfunction is more frequent and is thought to be related to iron deposition in the anterior pituitary. Increased iron content decreases signal intensity of spin-echo MRI images because T2 values are significantly shortened. Our purpose in this study was to evaluate by MRI iron deposition in the liver, testis and pituitary of 6 patients with haemochromatosis and severe hypogonadotrophic hypogonadism. Six subjects sereved as controls. There was a significant T2 shortening of the liver and pituitary i in patients with haemochromatosis compared with control patients. Therefore MRI detected iron overload in the pituitary and no iron in the testis, supporting the hypothesis of hypogonadotrophic pituitary insufficiency due to cellular damage induced by iron overload in the anterior pituitary gland. Correspondence to: Y. Miaux     

Whole-body MRI in children: current status and future applications

Whole-body MRI (WBMRI) is a novel technique that makes imaging of the whole patient in a manner similar to scintigraphy or positron emission tomography (PET) possible. Unlike the latter two methods, it is without exposure to radiation and thus gaining increasing importance and application in pediatrics. With the introduction of a moving tabletop, sequential movement of the patient through the magnet has become possible with automatic direct realignment of the images after acquisition. The common scan plane is coronal with additional planes being added depending on the indication. WBMRI is targeted for maximum coverage of the body within the shortest possible time using the minimum number of sequences. The evaluation of the bone marrow has been the primary indication thus inversion recovery sequences like STIR or TIRM are mostly used with the T1-weighted sequence being added variably. For correct evaluation of the bone marrow in the pediatric age group understanding normal pattern of marrow transformation is essential. The primary role of WBMRI has been in oncology for the detection of tumor spread and also for the follow-up and evaluation of complications. The initial comparative studies of WBMRI with scintigraphy and PET in children have shown the high diagnostic potential of WBMRI. Emerging potential applications of WBMRI include the evaluation for osteonecrosis, chronic multifocal recurrent osteomyelitis, myopathies, and generalized vascular malformations. Future use of WBMRI may incorporate non-accidental trauma, virtual autopsy, body fat mapping and diffusion-weighted imaging.