Brain MRI Findings of Carbon Disulfide Poisoning

Objective

To evaluate the findings of brain MRI in patients with carbon disulfide poisoning.

Materials and Methods

Ninety-one patients who had suffered carbon disulfide poisoning [male:female=87:4; age, 32-74 (mean 53.3) years] were included in this study. To determine the extent of white matter hyperintensity (Grade 0-V) and lacunar infarction, T2-weighted MR imaging of the brain was performed.

Results

T2-weighted images depicted white matter hyperintensity in 70 patients (76.9%) and lacunar infarcts in 27 (29.7%).

Conclusion

In these patients, the prevalent findings at T2-weighted MR imaging of the brain were white matter hyperintensity and lacunar infarcts. Disturbance of the cardiovascular system by carbon disulfide might account for these results.     

Value of MRI of the brain in patients with systemic lupus erythematosus and neurologic disturbance

Abstract Our objective was to review the frequency and pattern of signal abnormalities seen on conventional MRI in patients with suspected neuropsychiatric systemic lupus erythematosus (NP-SLE). We reviewed 116 MRI examinations of the brain performed on 85 patients with SLE, (81 women, four men, aged 21–78 years, mean 40.6 years) presenting with neurological disturbances. MRI was normal or nearly normal in 34%. In 60% high-signal lesions were observed on T2-weighted images, frequently in the frontal and parietal subcortical white matter. Infarct-like lesions involving gray and white matter were demonstrated in 21 of cases. Areas of restricted diffusion were seen in 12 of the 67 patients who underwent diffusion-weighted imaging. Other abnormalities included loss of brain volume, hemorrhage, meningeal enhancement, and bilateral high signal in occipital white-matter. The MRI findings alone did not allow us to distinguish between thromboembolic and inflammatory events in many patients. Some patients with normal MRI improved clinically while on immunosuppressive therapy. More sensitive and/or specific imaging methods, such as spectroscopy and perfusion-weighted imaging, should be investigated in these subgroups of patients with suspected NP-SLE.     

Osteogenic sarcoma: MR signal abnormalities of the brain in asymptomatic patients treated with high-dose methotrexate

The advent of lesions with high signal intensity in periventricular white matter was incidentally observed on T2-weighted images in one patient who underwent magnetic resonance (MR) imaging of the brain after administration of high-dose methotrexate (HDMTX) for osteogenic sarcoma. Twenty-one additional symptom-free patients who had been treated with the same regimen and 10 patients who had undergone cisplatin-based chemotherapy for testicular cancer also underwent examination. Fourteen of the patients with osteosarcoma showed high-signal-intensity lesions in white matter on T2-weighted images. The interval between the last course of chemotherapy and MR imaging was a factor in this finding, as 12 of 14 patients who underwent examination within 2 years after chemotherapy had a positive finding, as opposed to two of eight patients who underwent examination later. The patients with testicular cancer had normal MR images. The occurrence of MR imaging abnormalities in asymptomatic patients treated with HDMTX for osteogenic sarcoma may be subclinical evidence of treatment-related central nervous system toxicity.     

Spin-echo MRI of chronic intracerebral haematomas

Our purpose was to characterise the MRI appearances of clinically non-neoplastic chronic intracerebral haematomas (ICH). We examined 25 patients with a history of clinically non-neoplastic 0.5- to 1.5-year-old ICH who underwent prospective follow-up 1.0-T spin-echo MRI of the brain. On T1-weighted images most lesions gave lower signal than white matter and were isointense with cerebrospinal fluid (CSF). On T2-weighted images most were either totally low-signal and slit-like, or had a high-signal centre and a low-signal margin. The low-signal (haemosiderin) rim showed areas of discontinuity in 7 cases. Of 24 lesions, 4 showed small enhancing areas on contrast-enhanced images. In 10 cases the brain parenchyma surrounding the lesion showed high-signal on T2- and low signal on T1-weighted images, probably representing encephalomalacia. In 20 cases enlargement of a nearby CSF space was observed, and 14 cases showed atrophy of the brain stem ipsilateral to the lesion. We thus found more variation on MRI of clinically non-neoplastic chronic ICH than previously described. Received: 28 September 1995 Accepted: 18 January 1996     

Diffusion-weighted MR imaging in patients with phenylketonuria: relationship between serum phenylalanine levels and ADC values in cerebral white matter

PURPOSE: To prospectively determine the relationship between serum phenylalanine levels and apparent diffusion coefficient (ADC) values in the cerebral white matter of patients with phenylketonuria (PKU). MATERIALS AND METHODS: Institutional review board approval was obtained, and participants provided informed consent. Magnetic resonance (MR) imaging, which included T1- and T2-weighted, fluid-attenuated inversion-recovery (FLAIR), and diffusion-weighted examinations, was performed in 21 patients with PKU (nine male and 12 female patients; age range, 3-44 years; mean age, 19.4 years). ADC values in deep cerebral white matter were calculated for each patient. Serum phenylalanine levels were obtained in all patients within 12 days after MR imaging. Serum phenylalanine levels were measured in 16 patients 1 year before MR imaging. ADC values in cerebral white matter and serum phenylalanine levels were compared. A total of 21 control subjects (12 male and nine female patients; age range, 3-33 years; mean age, 20.6 years) underwent MR imaging. ADC values in cerebral white matter were compared with serum phenylalanine levels by using the Pearson correlation. RESULTS: Abnormal high signal intensity in white matter on T2-weighted and FLAIR MR images was noted in patients with PKU who had serum phenylalanine levels of more than 8.5 mg/dL (514.2 micromol/L). Diffusion in posterior deep cerebral white matter tended to be restricted in patients when increased serum phenylalanine levels were measured after MR imaging (r = -0.62). There was a correlation between ADC values in posterior cerebral white matter and serum phenylalanine levels measured 1 year before MR imaging (r = -0.77). ADCs of control subjects were significantly higher than ADCs of patients with PKU (P < .005). CONCLUSION: Posterior deep white matter in patients with PKU and a serum phenylalanine level of more than 8.5 mg/dL showed high signal intensity in white matter on T2-weighted and FLAIR MR images and revealed decreased ADC. We suggest that to avoid brain-restricted diffusion due to hyperphenylalanemia, patients with PKU should maintain serum phenylalanine levels of less than 8.5 mg/dL (514.2 micromol/L).     

Diffusion tensor imaging of brain tumours at 3T: a potential tool for assessing white matter tract invasion?

AIM: To determine whether diffusion tensor imaging (DTI) of brain tumours can demonstrate abnormalities distal to hyperintensities on T2-weighted images, and possibly relate these to tumour grade. MATERIALS AND METHODS: Twenty patients with histologically confirmed supratentorial tumours, both gliomas (high and low grade) and metastases, were imaged at 3T using T2-weighted and DTI sequences. Regions of interest (ROI) were drawn within the tumour, in white matter at various distances from the tumour and in areas of abnormality on DTI that appeared normal on T2-weighted images. The relative anisotropy index (RAI)-a measure of white matter organization, was calculated for these ROI. RESULTS: The abnormality on DTI was larger than that seen on T2-weighted images in 10/13 patients (77%) with high-grade gliomas. New abnormalities were seen in the contralateral white matter in 4/13 (30%) of these cases. In these high-grade tumours the RAI in areas of white matter disruption with normal appearance on T2-weighted images was reduced (0.19+/-0.04). Even excluding patients with previous radiotherapy this difference remains significant. In all non high-grade tumours (WHO grade II gliomas and metastases) the tumour extent on DTI was identical to the abnormalities shown on T2-weighted imaging and RAI measurements were not reduced (0.3+/-0.04). CONCLUSIONS: Subtle white matter disruption can be identified using DTI in patients with high-grade gliomas. Such disruption is not identified in association with metastases or low-grade gliomas despite these tumours producing significant mass effect and oedema. We suggest the changes in DTI may be due to tumour infiltration and that the DTI may provide a useful method of detecting occult white matter invasion by gliomas.     

CT detection of basal ganglion lesions in neurofibromatosis type 1: correlation with MRI

Summary Prospective study of CT and MRI in 41 consecutive children with suspected type 1 neurofibromatosis revealed basal ganglion lesions on T2-weighted spin echo images in 22 cases (54%) and on CT in only 7 of those (32%). T2-weighted spin-echo MRI also revealed multiple signal changes in the supra- and infratentorial white matter and brain stem that went completely unnoticed on CT.     

HTLV-I carrier with unusual brain MR imaging findings

We describe unusual brain MR imaging findings in a patient who is an HTLV-I carrier without myelopathy. T2-weighted MR images showed hyperintense signal abnormalities in the pyramidal tract, superior and middle cerebellar peduncles, and decussation of the superior cerebellar peduncles, in addition to subcortical white matter involvement. Diffusion-weighted images also showed hyperintense signal abnormalities in the same regions by T2 shine-through effect.     

Reye's syndrome with cortical laminar necrosis: MRI

Serial MRI findings are described in two patients with Reye's syndrome, demonstrating diffuse cortical and white matter changes. In the acute stage, T2-weighted images showed subtle but definite laminar high signal and contrast-enhanced T1-weighted images laminar enhancement, along the entire cerebral cortexbilateraly. In the chronic stage, unenhanced T1-weighted images showed diffuse cortical laminar high signal. These characteristic MRI features seemed very similar to those of laminar cortical necrosis in hypoxic brain damage. MRI also displayed delayed white matter changes with cerebral atrophy.     

Congenital muscular dystrophy with merosin deficiency: MRI findings in five patients

We present the MRI findings in five patients with congenital muscular dystrophy (CMD) and merosin (laminin α 2) deficiency, which was total in one and partial in four. In one patient with partial merosin deficiency, MRI was normal. The other four patients had supratentorial white matter abnormalities. In three, T2-weighted images revealed subcortical, deep lobar and periventricular high signal in white matter, while in the other there were only small peritrigonal areas of increased signal. On T1-weighted images, there was slightly low signal. Cortical abnormalities were absent. None of these changes were accompanied by symptoms or signs of central nervous system involvement. White matter abnormalities in a patient with CMD should prompt investigation of merosin. Received: 22 December 1997 Accepted: 22 April 1998     

Inversion-recovery echo-planar MR in adult brain neoplasia.

PURPOSEA T1-weighted multishot inversion-recovery (IR) echo-planar MR imaging (EPI) sequence was developed to improve intracranial tissue differentiation; its diagnostic utility was compared with that of conventional axial T1-weighted spin-echo and axial T2-weighted turbo spin-echo sequences.METHODSEighteen patients with known or suspected primary or metastatic brain neoplasia were imaged in a 1.5-T unit with IR-EPI sequences. Three observers measured gray/white matter contrast-to-noise ratios and subjectively compared IR-EPI sequences with T1-weighted spin-echo and T2-weighted turbo spin-echo sequences for gray/white matter discrimination, visibility of intracranial and vascular structures, overall lesion conspicuity, size of lesion(s), and presence and severity of artifacts.RESULTSTwenty-four lesions (including neoplasia, infarction, treatment-associated encephalomalacia, nonneoplastic white matter signal abnormalities, and basilar artery dolichoectasia) were detected in 12 patients. Basilar artery dolichoectasia was not included in subsequent statistical analysis. Pulsatile flow artifacts were markedly reduced on IR-EPI sequences relative to those on T1-weighted spin-echo sequences. Gray/white matter contrast was greater on IR-EPI images than on T1-weighted spin-echo images. Periaqueductal gray matter, basal ganglia, optic tracts, cranial nerve V, and claustrum were seen better or as well on IR-EPI images as compared with T1-weighted spin-echo images. IR-EPI was more sensitive to magnetic sensitivity effects, with resultant decreased visibility of cranial nerves VII and VIII and the orbital portion of the optic nerves. For noncontrast sequences, lesion conspicuity was better on IR-EPI images than on T1-weighted spin-echo images in 16 (70%) of 23 lesions and was equal on the two sequences in seven (30%) of 23 lesions. Lesion size, including surrounding edema, was greater on IR-EPI images than on T2-weighted turbo spin-echo images in two (9%) of 23 cases and equal in 21 (91%) of 23 cases. Hyperintense foci of methemoglobin were more conspicuous on T1-weighted spin-echo images.CONCLUSIONMultishot IR-EPI is superior to conventional T1-weighted spin-echo imaging for parenchymal tissue contrast and lesion conspicuity, and is equal to T2-weighted turbo spin-echo imaging in sensitivity to pathologic entities.     

儿童结节性硬化症14例的磁共振表现

目的 探讨结节性硬化症(TSC)的磁共振影像表现。方法 收集2002年3月至2005年4月间临床证实的结节性硬化症14例,全部病例均进行MR检查,其中3例进行增强检查。不合作儿童检查前采用6.5%水合氯醛保留灌肠镇静睡眠。结果 全部病例均显示大小不等(1~5mm)的室管膜下结节。皮层或皮层下结节10例,表现为脑回核心样病灶和H型病灶。白质异常信号6例,分别呈线状、楔形、不规则形。室管膜下巨细胞星形细胞瘤2例,肾血管平滑肌脂肪瘤1例。结论 MRI对TSC诊断的敏感性高,是首选的影像学检查方法。室管膜下结节是TSC最重要的MR影像学表现之一,以T₁加权成像(T₁WI)及梯度回波序列显示效果最佳。T₂加权成像(T₂WI)及液体衰减反转恢复序列(FLAIR)对TSC大脑皮层或皮层下区结节、脑白质区病灶的显示优于T₁WI。     

Brain in eclampsia: MR imaging with clinical correlation

Cranial magnetic resonance (MR) imaging was performed on eight consecutive patients with generalized tonic-clonic seizures caused by eclampsia. Each patient underwent serial neurologic examinations until all symptoms resolved. Six of those eight patients underwent follow-up MR imaging. These patients were compared with those in previous case reports of MR imaging abnormalities of the brain in eclampsia. MR imaging typically demonstrates bilateral hyperintense lesions on T2-weighted images and iso- to hypointense lesions on T1-weighted images. MR imaging abnormalities are most commonly located in the distribution of the posterior cerebral circulation and are associated with visual disturbances. Basal ganglia and deep white matter lesions are less common and are associated with mental status changes. Most lesions seen at MR imaging in patients with eclampsia are reversible.     

MRI of cortical dysplasia – correlation with pathological findings

Cortical dysplasia (CD) is the most epileptogenic structural lesion associated with epilepsy and patients with intractable seizures caused by this condition are good surgical candidates. MRI plays an important role in detecting the abnormalities of CD. We clarified the MRI characteristics of CD by comparing imaging and histological findings in 20 patients with intractable seizures who underwent surgical resection. There were 12 males and eight females, mean age at operation was 15 years. MRI was performed at 1.5 tesla; T1-weighted, T2- and proton density-weighted spin-echo and fluid-attenuated inversion-recovery (FLAIR) images were obtained. The lesions were in the frontal lobe in nine cases, temporal in two, occipital in another two, insular in one and multilobar in six. Blurring of the grey/white matter junction was seen in all patients, and T2 prolongation in white matter and/or at the grey/white matter junction in 19. Abnormal signal intensity was more frequent in the white matter or at the grey/white matter junction than in the grey matter. FLAIR images made this abnormal high signal easier to appreciate, and we thought them very useful in this context. In areas of T2 prolongation, we saw dysplastic neurones and/or balloon cells, dysmyelination, and ectopic neuronal clustering histologically; glial proliferation played an important role in prolonging T2. Received: 24 November 2000/Accepted: 6 February 2001     

Periventricular hyperintensity on magnetic resonance imaging correlated with brain ageing and atrophy

Summary Fifty-two patients with cerebrovascular risk factors without neurological abnormalities were reviewed with respect to periventricular hyperintensity (PVH) on T2-weighted magnetic resonance imaging (MRI); brain atrophy was also assessed by CT and T1-weighted MRI. Extensive PVH showed a stronger correlation with agerelated atrophy than mild or absent PVH. The relative volume of brain affected by PVH, calculated by computer, also correlated with brain atrophy, especially ventricular enlargement. The effects of PVH on brain ageing and atrophy is discussed.     

Comparative evaluation of magnetization transfer contrast and fluid attenuated inversion recovery sequences in brain tuberculoma

AIM: To compare T1-weighted magnetization transfer (MT) with fluid attenuated inversion recovery (FLAIR) imaging for evaluating conspicuity and number of lesions in individuals with brain tuberculoma. MATERIALS AND METHODS: In all 28 patients with brain tuberculoma underwent MR examination using fast spin-echo (FSE) T2, spin-echo (SE) T1, T1-weighted MT and FLAIR imaging. Post-contrast T1-weighted MT imaging was taken as the gold standard for assessing the number of lesions. Tuberculomas detected both on T1-weighted MT and FLAIR imaging were examined for the wall to be defined, and were divided into two groups on the basis of presence (group 1) or absence (group 2) of perilesional oedema visible on FLAIR imaging. The mean signal intensity of the wall of the lesions and adjacent oedema or brain parenchyma was analyzed qualitatively and quantitatively. RESULTS: The number of lesions detected on T1-weighted MT was higher than on FLAIR imaging (209 versus 163). Conspicuity in both groups was better on T1-weighted MT images qualitatively as well as quantitatively. The difference in the signal intensity of the wall of the lesion and perilesional oedema was statistically significant only on T1-weighted MT images in group 1 (p=0.0003 versus 0.3), whereas in group 2 it was statistically significant both on T1-weighted MT and FLAIR imaging (p=0.009 versus 0.05). CONCLUSION: FLAIR imaging is not helpful in the examination of brain tuberculomas compared with T1-weighted MT imaging, as it neither contributes to the characterization of lesion nor assesses the true disease load.     

MR imaging of the brain in patients with migraine headaches

Forty-one patients with migraine headaches were referred for MR imaging of the brain. Intermediate and T2-weighted images were obtained to determine the frequency of areas of high intensity within the white matter. The average age of these patients was 29.8 years; only five were over 40 years old. Each patient was evaluated in the axial plane with long TR/short and long TE images. Twenty-three patients also had T1-weighted short TR/short TE MR scans; enhancement with gadopentetate dimeglumine was used in three patients. Intracranial abnormalities were seen in only six patients: foci or white matter high intensity on intermediate and T2-weighted images in five and a venous angioma in one. Prior studies have indicated that parenchymal brain abnormalities may be found in up to 46% of patients with migraines. The current study demonstrated parenchymal brain lesions in only 12%. This study suggests that the frequency of foci of high intensity seen on long TR sequences in the migraine patient is much lower than previously reported, especially in patients under 40 years old (5.5% in our series).     

Cerebrotendinous xanthomatosis: the spectrum of imaging findings and the correlation with neuropathologic findings

PURPOSE: To describe imaging findings and their neuropathologic correlate in patients with cerebrotendinous xanthomatosis (CTX). MATERIALS AND METHODS: Computed tomographic (CT) and magnetic resonance (MR) images in 24 patients with symptoms (mean age at time of imaging, 37 years; mean disease duration, 18 years) were reviewed for site and frequency of brain, spinal cord, and Achilles tendon involvement. Two patients died, and imaging findings were compared with postmortem neuropathologic findings. RESULTS: Apart from nonspecific supratentorial atrophy and deep white matter changes, more typical hyperintense lesions were seen on T2-weighted images in the dentate nucleus (in 79% of patients), globus pallidus, substantia nigra, and inferior olive and extended into adjacent white matter as disease progressed. In these locations, lipid crystal clefts and perivascular macrophages, neuronal loss, demyelination, fibrosis, and reactive astrocytosis were found at microscopic examination. Hypointensity was sometimes found on T2-weighted images in the dentate nucleus and was related to deposition of hemosiderin and calcifications. CT depicted fewer lesions; all had low attenuation, except for the calcifications. Spinal cord MR imaging revealed increased signal intensity in the lateral and dorsal columns on T2-weighted images. Achilles tendon xanthomas displayed intermediate signal intensity on T1- and T2-weighted images. CONCLUSION: The typical pattern of MR imaging findings reflects the classic histopathologic findings and should prompt the diagnosis of CTX.     

MR梯度回波T2^＊WI检出脑微出血

目的：MR梯度回波T2^＊WI可检出无症状性脑微出血,本研究旨在探讨脑微出血的发生率、部位以及与高血压、脑卒中、脑室周围白质高信号的相关性。方法：在1年时间内共有375例患者在常规MRI／序列的基础上加扫T2^＊加权序列,排除了存在脑血管畸形出血、颅内占位、外伤、手术史等病例,共有324例进行分析处理。结果：脑微出血37例,总的发生率为11．4％,尤其位于基底节／放射冠（n=22）、丘脑（n=15）、小脑（n=14）和脑叶区域（n=15）,脑微出血主要见于存在脑中风史病例,与年龄、高血压、脑白质疏松症（脑室周围白质高信号）存在相关性（P〈0．001）。在2年多的影像学随访过程中,共发现2例（5．4％）出现新鲜脑出血。结论：MR T2^＊加权像可用于检出脑微出血,其发生提示存在脑微小血管病变,存在继发出血的可能性,建议对于60岁以上的老年人尤其是存在脑中风的病例,MR T2^＊加权应作为常规扫描序列。     

脑脂肪栓塞的MRI诊断价值

目的：研究MIU对脑脂肪栓塞的影像学诊断及其临床价值。方法：回顾性分析了25例经临床诊断为脂肪栓塞综合征(FES)的脑部MRI资料。MRI检查采用0．3T、0．5T低场强设备，行常规SE T1WI、FSE T2WI和FI FLAIR，16例病人在发病后1～3月内行MRI复查，CT检查22例。结果：脑脂肪栓塞(CFE)的MRI表现为散在多发、对称分布的点、片状等或长T1长T2信号灶，边缘多较模糊，主要位于基底节区、脑干深部、深部白质及分水岭区白质。MRI复查示随脑内病灶的吸收，病人症状得到不同程度的改善，因此，MRI对判断预后及指导治疗具有重要意义。结论：MRI可为CFE的诊断提供直接的证据，应作为诊断CFE的常规手段。