Diffusion-weighted magnetic resonance imaging in Wernicke's encephalopathy

OBJECTIVE: To report diffusion-weighted imaging (DWI) findings and postulate the pathogenic mechanism of Wernicke's encephalopathy (WE). PATIENT: A 47-year-old-woman presented with altered consciousness, ophthalmoplegia, and ataxia. DWI revealed the abnormal signal changes in periaqueductal gray matter, mamillary bodies and bilateral medial thalami. Apparent diffusion coefficient (ADC) map revealed the high signal intensity lesions in bilateral medial thalami, suggestive of vasogenic edema. The abnormal signal intensity lesions disappeared on follow-up imaging with clinical improvement. CONCLUSIONS: Vasogenic edema plays an important role in the pathogenesis of WE and can be reversed by proper management. DWI findings in the early stage of WE may provide useful information about the prognosis.     

Diagnostic Value of Apparent Diffusion Coefficient Hyperintensity in Selected Patients With Acute Neurologic Deficits

BACKGROUND AND PURPOSE: A pattern of decreased intensity on apparent diffusion coefficient (ADC) maps is useful in the early detection of ischemic brain injury. Less information exists with regard to patients with acute neurologic deficits in whom there is abnormal conventional magnetic resonance imaging (MRI) and increased ADC intensity. METHODS: The authors identified 13 patients with acute neurologic deficits who underwent diffusion MRI and had calculated ADC maps demonstrating hyper-intensity in regions characterized by computed tomography hypodensity and MRI T2 hyperintensity. The initial and follow-up imaging characteristics and clinical syndromes were recorded. RESULTS: Clinical syndromes included hypertensive encephalopathy, posterior leukoencephalopathy, hyperperfusion following carotid endarterectomy, venous sinus thrombosis, HIV encephalopathy, and brain tumor. Diffusion-weighted imaging (DWI) was hyperintense in 3 of 13 patients, isointense in 4 of 13 patients, heterogeneous in 3 of 13 patients, and hypointense in 3 of 13 patients. The ADC values in these regions were significantly higher than those in control regions (P < .0001). At early follow-up, MRI abnormalities resolved completely in 3 of 13 patients and partially in 9 of 13 patients. MRI abnormalities were unchanged in 1 patient. CONCLUSIONS: In the evaluation of patients with acute neurologic deficits, ADC hyperintensity may identify a subset of patients with vasogenic edema of nonischemic etiology. Frequently, these conditions are potentially reversible if appropriately managed. DWI and conventional images alone are not sufficient to identify these neurologic conditions.     

MR Atypical Wernicke Encephalopathy Showing Extensive Brain Stem and Diencephalic Involvement

Wernicke encephalopathy (WE) is a serious neurological disorder caused by thiamine (vitamin B1) deficiency. We report a case of atypical and extensive location of abnormal signal lesions on magnetic resonance imaging (MRI) in a man with alcohol abuse with WE. MRI performed on the first hospital day showed signal intensity alterations extending in the whole brain stem and diencephalon; the mismatch between diffusion‐weighted images and apparent diffusion coefficient map was highly suggestive of vasogenic edema. This report further supports the view that WE may represent a spectrum of radiological entities and can have a wide spectrum of manifestations on MRI; thus, clinical features are essential to diagnose it.     

Consistency between magnetic resonance diffusion-weighted images and pathological findings in a hyperacute cerebral infarction rabbit model

BACKGROUND： Because magnetic resonance diffusion-weighted imaging is sensitive to water molecule movement, it has particular advantages for early diagnosis of cerebral infarction. However, the relationship between apparent diffusion coefficient changes with ischemia time, particularly relative apparent diffusion coefficient and tissue pathological changes remains controversial. OBJECTIVE： To explore the correlation between apparent diffusion coefficient changes and pathologic changes in hyperacute cerebral infarction. DESIGN, TIME AND SETTING： A randomized, controlled, animal experiment of neuroimaging. The study was performed at the Laboratory of Radiology Department, Longgang Central Hospital of Shenzhen from October 2007 to October 2008. MATERIALS： Magnetic resonance scanner was purchased from Philips Medical Systems, Best, the Netherlands. METHODS： A total of 42 healthy, adult, New Zealand rabbits were randomly assigned into sham-operation, ischemia 0.5-, 1-, 2-, 3-, 4-, and 6-hour groups, with six animals in each group. Local cerebral ischemia model was established by right middle cerebral artery occlusion, and cranial MRI scanning and pathologic observation were performed, respectively, at 0.5, 1,2, 3, 4, and 6 hours following ischemia. The middle cerebral artery of sham-operation group was only exposed, but not occluded. Images at the above-mentioned time points were also collected. MAIN OUTCOME MEASURES： Apparent diffusion coefficient and relative apparent diffusion coefficient values of abnormal signal on diffusion-weighted imaging were calculated and compared with pathological changes in the ischemic region. RESULTS： No abnormal diffusion-weighted imaging signals or pathological changes were observed in the sham-operation group. Abnormal signal intensity on diffusion-weighted imaging was first observed in the 0.5-hour group. Apparent diffusion coefficient and relative apparent diffusion coefficient values decreased in all middle cerebral artery occlusion rabbits and reached lowest levels at 3 hours, followed by a gradual increase. The right ischemic basal ganglia region with high signal intensity on diffusion-weighted imaging extended with increasing time of occlusion, and the pathologic outcome corresponded with MRI changes. CONCLUSION： Relative apparent diffusion coefficient values changed regularly with ischemia time and displayed good correspondence to pathological manifestations.     

Wernicke encephalopathy☆ Clinical presentation and MR images in two nonalcoholic patients

The aim of the present study was to investigate the importance of and correlation between clinical presentations and magnetic resonance imaging （MRI） of two different cases of nonalcoholic Wernicke encephalopathy. Case l ： A 63-year-old man with a diagnosis of incomplete mechanical intestinal obstruction. His abdominal symptoms were improved by gastrointestinal decompression, but blurred vision, hypoacusis, dizziness, and unsteady gait were noted. His illness deteriorated to confusion on day seven. MRI showed hyperintense lesions in the medial thalami, tectum of the midbrain, and the periaqueduct region on T2- and diffusion-weighted images. Thiamine therapy was commenced immediately with good results. Case 2： A 22-year-old woman was admitted for sudden-onset confabulation and unsteady gait after hyperemesis gravidarum. She had no history of alcohol or any medication. Brain MRI was normal. The patient experienced relief after Vitamin B1 treatment. These results suggest that brain MRI can define characteristic abnormalities in Wernicke encephalopathy, and that diffusion-weighted imaging may improve the diagnosis sensitivity. In addition, the MRI images may be correlated to the clinical stage and severity of the disease. Nevertheless, the clinical features are essential for correct diagnosis.     

Diffusion-weighted MR findings in isolated angiitis of the central nervous system (IACNS)

OBJECTIVES: To describe the diffusion-weighted MR (DWI) findings of isolated angiitis of the central nervous system (IACNS) and narrow the differential diagnosis. METHODS: The DWI findings of two IACNS patients. Apparent diffusion coefficient (ADC) values were measured in the abnormal lesions, and DWI and T2-weighted MR images were visually inspected. RESULTS: IACNS was diagnosed based on clinical history, MR findings and cerebral angiographic findings. DWI showed hyperintense lesions with heterogeneous ADC values (287-1359 x 10(-6) mm2/s), which indicate the coexistence of cytotoxic and vasogenic oedema. CONCLUSIONS: The findings suggest that the various stages of inflammatory process with ischaemia might exist in IACNS and allow a differentiation from the usual arterial ischaemic infarction. DWI with ADC map can be a useful non-invasive diagnostic test increasing specificity in the diagnosis of IACNS, combined with conventional MRI and cerebral angiography.     

Diffusion-weighted MR findings of central pontine and extrapontine myelinolysis

Diffusion-weighted MR (DWI) can detect changes in water diffusion associated with cellular dysfunction, which enables the differentiation of cytotoxic edema from vasogenic edema. In this study on DWI findings in central pontine (CPM) and extrapontine myelinolysis (EPM), DWI showed high signal intensities in the bilateral pons, midbrain, and genu of the corpus callosum. The corresponding apparent diffusion coefficient values were rather low. This suggests that cytotoxic edema does in fact exist in CPM and EPM and that DWI can be useful in the rapid diagnosis and prediction of the various types of edema occurring in active demyelinating diseases.     

Diffusion-weighted magnetic resonance imaging findings at early stage of acute Wernicke encephalopathy]

We describe a patient with acute Wernicke encephalopathy (WE) in whom diffusion-weighted magnetic resonance imaging (DWI) were helpful for early diagnosis. A 66-year-old alcoholic man was admitted to our department because of recurrent mild drowsiness. Thiamine concentrations in blood were at the lower limit of normal. DWI demonstrated an abnormal signal intensity in the dorsal part of the midbrain, and high-dose thiamine therapy was started. These lesions disappeared on DWI after one month of follow-up, in association with clinical improvement. These findings suggest that DWI is useful for detecting WE at the early stage when high-dose thiamine treatment can improve the prognosis of WE.     

磁共振弥散加权成像对急性脑梗死的诊断价值

目的:探讨磁共振弥散加权成像(DWI)对急性脑梗死的诊断价值.方法:对26例急性脑梗死患者(发病＜6h4例、6-24h14例、1-7d8例)进行常规MRI(T,flair,T2WI,T2flair)检查以及DWI检查,并由计算机算出表观扩散系数(ADC)图.结果:发病＜6h的4例患者常规MRI未见异常;DWI均出现高信号;ADC均为低信号.发病6h-7d的22例患者MRI T2 WI均为高/稍高信号,T1 flair均为低/稍低信号;DWI均为高信号;ADC均为低信号.结论:DWI能在超早期显示急性脑梗死的病灶,对急性脑梗死有着非常重要的诊断价值.     

EFNS guidelines for diagnosis,therapy and prevention of Wernicke encephalopathy

Background: Although Wernicke encephalopathy (WE) is a preventable and treatable disease it still often remains undiagnosed during life. Objectives: To create practical guidelines for diagnosis, management and prevention of the disease. Methods: We searched MEDLINE, EMBASE, LILACS, Cochrane Library. Conclusions and recommendations:

• 1 The clinical diagnosis of WE should take into account the different presentations of clinical signs between alcoholics and non alcoholics (Recommendation Level C); although prevalence is higher in alcoholics, WE should be suspected in all clinical conditions which could lead to thiamine deficiency (good practice point – GPP).
• 2 The clinical diagnosis of WE in alcoholics requires two of the following four signs; (i) dietary deficiencies (ii) eye signs, (iii) cerebellar dysfunction, and (iv) either an altered mental state or mild memory impairment (Level B).
• 3 Total thiamine in blood sample should be measured immediately before its administration (GPP).
• 4 MRI should be used to support the diagnosis of acute WE both in alcoholics and non alcoholics (Level B).
• 5 Thiamine is indicated for the treatment of suspected or manifest WE. It should be given, before any carbohydrate, 200 mg thrice daily, preferably intravenously (Level C).
• 6 The overall safety of thiamine is very good (Level B).
• 7 After bariatric surgery we recommend follow‐up of thiamine status for at least 6 months (Level B) and parenteral thiamine supplementation (GPP).
• 8 Parenteral thiamine should be given to all at‐risk subjects admitted to the Emergency Room (GPP).
• 9 Patients dying from symptoms suggesting WE should have an autopsy (GPP).

     

Wernicke脑病综合征10例临床分析

目的:探讨Wernicke脑病(WE)的病因、临床表现特点、MRI表现及预后。方法:对10例WE患者的病因、临床表现、头颅MRI特点和预后进行了回顾性分析。结果:WE病因多与维生素B1缺乏有关,主要临床表现为眼肌麻痹,共济失调、精神异常三联症,但也可以表现为周围神经病、言语障碍等。头颅MRI有特异性部位的异常信号改变。及时予以维生素B1治疗者预后多良好。结论:提高临床对WE的认识,有利于早诊断、早干预,有助于改善WE的预后。     

Use of high b value diffusion-weighted magnetic resonance imaging in acute encephalopathy/encephalitis during childhood

Aim

To determine the use of high b value diffusion-weighted imaging (DWI) in the diagnosis and assessment of acute febrile encephalopathy/encephalitis in childhood.

Posterior reversible encephalopathy syndrome

Posterior reversible encephalopathy syndrome (PRES) is a clinico-neuroradiological entity with typical symptoms and symmetric high-signal intensity lesions in the bilateral parieto-occipital lobes on T2-weighted or fluid-attenuated inversion recovery (FLAIR) MRI. We described three patients with PRES of varied etiologies. Patient 1 was a young man with severe hypertension who presented with headache and visual disturbance. Patient 2 had leukemia and was receiving umbilical cord blood cell transplantation with immunosuppressant, and developed PRES with convulsions. Patient 3 was a pregnant woman with renal failure, who repeatedly developed PRES with convulsions. FLAIR and apparent diffusion coefficient mapping were useful in detecting PRES lesions in our patients, although diffusion-weighted imaging and CT scans had limited use in the diagnosis. Adequate and prompt treatment with antihypertensive medication immediately ameliorated the symptoms, with improvement of abnormal MRI findings. In previous reports, delayed diagnosis might have affected the prognosis. Further work on the clinical manifestations of PRES and its therapy is required.     

Diffusion-weighted imaging study of patients with essential tremor.

The pathophysiology of essential tremor (ET) is unknown. PET and fMRI studies have revealed bilateral activation and (1)H-MRS studies metabolic abnormalities in the cerebellum and other functionally related brain structures in ET. Diffusion-weighted imaging (DWI) was used to search for evidence of tissue integrity abnormalities in these areas in ET patients and 10 matched controls by calculating water apparent diffusion coefficients (ADCs). Regions of interest included the left and right cerebellum, red nucleus, thalamus, caudate, putamen, pallidum, and frontal white matter. Histograms of ADCs were generated for all pixels in the infratentorial compartment and manually segmented areas corresponding to brainstem, vermis, and cerebellar hemispheres. ADC values were similar in all brain areas in patients and controls. Our study did not detect changes affecting the investigated brain regions in ET patients. These findings argue against major structural damage in the ET brain, although more subtle neurodegenerative changes cannot be ruled out.     

A case of autoimmune thyroid disease presenting posterior reversible encephalopathy syndrome

A 40-year-old woman was admitted to our hospital with disturbance of consciousness and seizure. We diagnosed encephalopathy associated with autoimmune thyroid disease (EAATD). Fluid-attenuated inversion recovery and diffusion-weighted MRI demonstrated hyperintense lesions in the left occipitotemporal lobe on admission, but these findings disappeared on day 11 without neurological deficits, compatible with posterior reversible encephalopathy syndrome (PRES). We report here this case of autoimmune thyroid disease presenting as PRES.     

Magnetic Resonance Reflects the Pathological Evolution of Wernicke Encephalopathy

BACKGROUND AND PURPOSE: Wernicke encephalopathy (WE) is an acute phase of Wernicke-Korsakoff syndrome. Pathologic findings change between acute and chronic phases. Only a few magnetic resonance imaging (MRI) studies have been done to date. METHODS: To correlate the MRI findings in acute and chronic stages of WE with the known pathologic information, 15 consecutive patients with WE were examined with MRI: 3 before thiamine treatment, 7 within 24 hours of thiamine treatment, 4 between the second and sixth day after thiamine treatment, and 1 fifty-five days after thiamine treatment. Nine of the patients had follow-up MRI between 2 days and 33 months. T1-weighted, proton, and T2-weighted axial images were obtained with additional 5-mm-thick T1-weighted sagittal and coronal images to better visualize the mammillary bodies. RESULTS: In the acute WE, MRI showed high signal intensityon T2-weighted images in periaqueduct and medial thalamic regions. In a few patients with alcoholism, vermian and mammillary body atrophies and third ventricular enlargements were noted. In the chronic phase of WE, T2 hyperintensity disappeared but mammillary bodies and cerebellar vermis became atrophic and third ventricular enlargements were evident. High signal intensity on T2-weighted images disappeared as early as 2 days, and atrophic changes appeared as early as 1 week. CONCLUSION: MRI is useful for in vivo monitoring and reflects the pathological evolution in acute and chronic phases of WE.     

Quantitative evaluation of brainstem involvement in multiple system atrophy by diffusion-weighted MR imaging

Abstract. In multiple system atrophy (MSA), symptoms associated with dysfunctions of the brainstem and autonomic nervous system are important prognostic factors. We investigated brainstem involvement in 12 patients with MSA with predominant cerebellar symptoms (MSA-C) (mean age, 56.3 ± 9.9 years, median disease duration, 3 years), and 11 controls (57.6 ± 12.0 years) matched for age using diffusion-weighted MR imaging (DWI). We demonstrated that apparent diffusion coefficients (ADCs) in the pons and middle cerebellar peduncle of MSA-C patients are significantly higher than those of normal controls even though the patients are in the early stage of the disease. Furthermore, we demonstrated that increased ADC values correlated well with the disease duration. The current study demonstrated that DWI is a useful noninvasive method for the quantitative evaluation of the brainstem involvement in MSA-C patients.