Diffuse leptomeningeal hyperintensity on fluid-attenuated inversion recovery MR images in neurocutaneous melanosis

Neurocutaneous melanosis (NCM) is a rare neuroectodermal dysplasia characterized by large or multiple cutaneous congenital pigmented nevi and benign or malignant melanocytic tumors of the leptomeninges. Although the MR manifestations of this disease have been reported in a small series of cases, the usefulness of fluid-attenuated inversion recovery (FLAIR) MR findings has not been documented. We present a case of NCM that showed diffuse leptomeningeal hyperintensity on FLAIR images. This FLAIR finding may be a clue to the detection of leptomeningeal abnormalities in NCM.     

MR findings of desmoplastic cerebral astrocytoma of infancy

Desmoplastic cerebral astrocytoma of infancy (DCAI) presents as a large supratentorial mass consisting of a central cystic component and an enhancing solid component associated with peripheral dural attachment. We report the unusual MR findings of a DCAI that differed from previously reported cases in terms of the presence of calcification, which is not considered a feature of this tumor, and the absence of an enhancing peripheral dural component.     

MR imaging features of clear-cell meningioma with diffuse leptomeningeal seeding

Clear-cell meningioma is a rare disease entity showing a more aggressive nature, clinically, than those of other subtypes of meningioma. It occurs in younger persons and commonly in the spinal canal. The recurrence rate has been reported to be as high as 60%. We present a case of clear-cell meningioma in a 17-year-old man in whom initial MR imaging showed localized leptomeningeal enhancement that had progressed into the entire subarachnoid space after surgical resection of the primary tumor.     

Diffuse leptomeningeal oligodendrogliomatosis: radiologic/pathologic correlation

We present the radiologic and pathologic findings in a boy who presented with diffuse leptomeningeal enhancement and whose clinical status deteriorated over the course of 5 years. During this period, MR images showed progression of the enhancement in the subarachnoid spaces, formation of intraaxial cysts, and hydrocephalus. Autopsy findings revealed diffuse oligodendroglioma throughout the leptomeninges of the brain and spine, with no definite intraaxial focus. The radiologic and pathologic features of diffuse leptomeningeal oligodendrogliomatosis are reviewed.     

脑星形细胞瘤的MR灌注成像研究

目的 :研究MR灌注成像的扫描技术、后处理技术及其评价脑星形细胞瘤的价值。方法 :本组病例包括星形细胞瘤 40例、转移瘤 3 0例、正常对照组 3 0例 ,均行MR平扫及灌注检查。结果 :不同部位的正常脑血流灌注量不一致。正常人脑灰、白质相对血容量rCBV(relativecerebralbloodvolume)值为 1.5 6± 0 .3 9。Ⅲ、Ⅳ级星形细胞瘤的rCBV值显著高于正常脑实质者 (P <0 .0 1) ,二者之间差异有显著性意义 ,但IV级星形细胞瘤的rCBV值变化较大。星形细胞瘤与转移瘤病变本身的rCBV值差异无显著性意义 (P >0 .0 5 ) ,但二者的rCBV值均高于正常脑实质。星形细胞瘤“邻近水肿区”的rCBV值显著高于转移瘤周围“邻近水肿区”的rCBV值 (P <0 .0 1) ,而星形细胞瘤、转移瘤“远离水肿区”的rCBV值间差异无显著性意义 (P >0 .0 5 )。结论 :MR灌注成像可精确提示正常脑实质及病变的血流状态 ,并能鉴别颅内原发性和继发性病变     

MR of leptomeningeal melanosis in children

Purpose: To delineate the magnetic resonance (MR) appearance of leptomeningeal melanosis in children. Method: Retrospective review of the medical, surgical, pathologic and MR findings in four children with a confirmed histologic diagnosis of leptomeningeal melanosis. The brain MR was performed with Tl- and T2-weighted images in all four children and three had T1-weighted post-gadolinium images. Two of the children also had T1-weighted post gadolinium spine images. Results: The MR brain findings consisted of cortical plaque and nodular hyperintense lesions on the noncontrast T1-weighted images in one child, marked, diffuse leptomeningeal enhancement in two children, and an enlarged, hypointense left temporal lobe with adjacent mild leptomeningeal enhancement in one child. The MR spine findings consisted of diffuse leptomeningeal enhancement in one child and hyperintensity of the cerebrospinal fluid in the other. Conclusion: The T1-weighted pre- and post-contrast images were the best to demonstrate the MR findings in leptomeningeal melanosis which consisted of either diffuse or localized enhancement of the leptomeninges; or cortical plaque and nodular hyperintense lesions pre-contrast.     

Loculated intracranial leptomeningeal metastases: CT and MR characteristics

Studies of twenty-five patients with loculated leptomeningeal tumor metastases diagnosed by CT and/or MR were analyzed retrospectively. Medulloblastoma was the most frequent primary tumor (8/25, 32%). Four subgroups of loculated patterns were identified. Type A included mass(es) limited to the subarachnoid space without obvious direct parenchymal infiltration; this pattern occurred in 12 patients, of whom five had associated diffuse pattern. Type B was characterized by mass(es) still predominantly in the subarachnoid space but with minor transpinal parenchymal infiltration; this pattern was found in five patients. Type C comprised subarachnoid mass(es) with marked transpinal extension mimicking parenchymal lesion; this pattern was observed in three patients. Type D consisted of subarachnoid mass(es) growing along the perineural CSF space; this pattern was noted in two patients. Additionally, two patients presented with combined A and C patterns, and one patient had a combined B and C pattern. More than half the patients (14/25, 56%) presented with a single lesion. The most frequent locations were the suprasellar cistern, ventricular walls, and lateral recesses of the fourth ventricle, Gd-DTPA-enhanced T1-weighted MR images appeared best for demonstrating the site and extent of disease. Recognition of the loculated patterns of leptomeningeal metastases, which are less common than the diffuse pattern, is important to radiologists and clinicians for correct diagnosis and proper management of patients with this disease.     

Loculated intracranial leptomeningeal metastases: CT and MR characteristics

Studies of twenty-five patients with loculated leptomeningeal tumor metastases diagnosed by CT and/or MR were analyzed retrospectively. Medulloblastoma was the most frequent primary tumor (8/25, 32%). Four subgroups of loculated patterns were identified. Type A included mass(es) limited to the subarachnoid space without obvious direct parenchymal infiltration; this pattern occurred in 12 patients, of whom five had associated diffuse pattern. Type B was characterized by mass(es) still predominantly in the subarachnoid space but with minor transpinal parenchymal infiltration; this pattern was found in five patients. Type C comprised subarachnoid mass(es) with marked transpinal extension mimicking parenchymal lesion; this pattern was observed in three patients. Type D consisted of subarachnoid mass(es) growing along the perineural CSF space; this pattern was noted in two patients. Additionally, two patients presented with combined A and C patterns, and one patient had a combined B and C pattern. More than half the patients (14/25, 56%) presented with a single lesion. The most frequent locations were the suprasellar cistern, ventricular walls, and lateral recesses of the fourth ventricle, Gd-DTPA-enhanced T1-weighted MR images appeared best for demonstrating the site and extent of disease. Recognition of the loculated patterns of leptomeningeal metastases, which are less common than the diffuse pattern, is important to radiologists and clinicians for correct diagnosis and proper management of patients with this disease.     

静脉性脑梗死MR影像特点

目的回顾总结静脉性脑梗死MRI及MRV影像表现,旨在提高影像诊断水平。方法对15例静脉性脑梗死的MR表现进行了回顾性分析,其中9例临床治疗后复查MR表现明显好转,临床症状明显改善。15例均行常规MRI平扫,其中9例同时进行MR增强及3DCE-MRV,6例行2DTOF MRV。结果 15例脑内多发病灶9例,单发病灶6例,其中2例脑梗死伴出血改变。15例中发生于额叶4例,顶叶6例,颞叶3例,枕叶1例,小脑1例。静脉栓塞部位11例为上矢状窦,1例直窦及左横窦,1例右侧横窦及乙状窦,2例皮层大脑浅静脉。9例行增强扫描,5例病灶内不规则强化,2例脑膜强化,3例无强化.7例MRV均显示栓塞的静脉血流信号丢失或缺损,3例出现异常静脉侧支或引流静脉异常扩张。结论静脉性脑梗死MR影像表现具有特征性,MRI结合MRV可以作为首选的无创检查方法,对静脉栓塞早期诊断和治疗有重要作用。     

Carotid-anterior cerebral artery anastomosis: MR angiographic features and literature review

Carotid-anterior cerebral artery anastomosis is a rare anomaly of the anterior part of the circle of Willis. We report here magnetic resonance (MR) angiographic findings in 2 patients with this anomaly. MR angiographic source images are useful in evaluating the anatomical details of this anomaly. Including the 2 present cases, 27 patients with this anomaly have been reported in the English-language literature. Thirty anomalous arteries were found in the 27 patients (R/L/bilateral=22/2/3). The reason for the right-sided predominance is unknown.     

Diffuse bone metastases in a case of astrocytoma

Presented is an unusual case of astrocytoma with diffuse multiple bony metastases in bone imaging. The classification, spread, and prognosis of astrocytoma are briefly reviewed.     

MR imaging of leptomeningeal metastases: comparison of three sequences

BACKGROUND AND PURPOSE: Recent work has shown that fluid-attenuated inversion recovery (FLAIR) imaging with contrast enhancement is highly sensitive for detecting subarachnoid space disease. We hypothesized that contrast-enhanced FLAIR imaging has superior sensitivity to contrast-enhanced T1-weighted MR imaging in detecting leptomeningeal metastases. METHODS: Sixty-eight patients referred for suspected leptomeningeal metastases underwent 74 MR imaging studies. The patients had either temporally related cytologic proof of leptomeningeal metastases or negative results of clinical follow-up confirming absence of leptomeningeal metastases. The MR imaging examinations included unenhanced and contrast-enhanced FLAIR images and contrast-enhanced T1-weighted MR images that were independently reviewed by two neuroradiologists blinded to the results of cytology. Each of the three sequences was reviewed individually and separately and was assigned a score of positive or negative for leptomeningeal metastases. Discrepancies were settled by consensus. RESULTS: Of the 17 studies of patients with cytology-proven leptomeningeal metastases, two were positive based on unenhanced FLAIR images, seven were positive based on contrast-enhanced FLAIR images, and 10 were positive based on contrast-enhanced T1-weighted MR images. Of the 57 studies of patients without leptomeningeal metastases, 53 were negative based on unenhanced FLAIR images, 50 were negative based on contrast-enhanced FLAIR images, and 53 were negative based on contrast-enhanced T1-weighted MR images. The sensitivity and specificity of unenhanced FLAIR images for detecting leptomeningeal metastases were 12% (two of 17) and 93% (53 of 57), respectively. The sensitivity and specificity for contrast-enhanced FLAIR images for detecting leptomeningeal metastases were 41% (seven of 17) and 88% (50 of 57), respectively. The sensitivity and specificity of contrast-enhanced T1-weighted MR images for detecting leptomeningeal metastases were 59% (10 of 17) and 93% (53 of 57), respectively. CONCLUSION: Contrast-enhanced fast FLAIR sequences are less sensitive than standard contrast-enhanced T1-weighted MR sequences in detecting intracranial neoplastic leptomeningeal disease.     

肿瘤软脑膜-蛛网膜转移的CT、MRI诊断

目的研究肿瘤软脑膜蛛网膜转移的ＣＴ、ＭＲＩ表现,并探讨两种检查方法对该病的诊断价值。方法回顾分析２１例肿瘤软脑膜蛛网膜转移的临床及影像学资料。病变经ＣＴ检查１６例,ＭＲＩ检查７例,其中经两种方法检查者２例。结果全部病例软脑膜蛛网膜下腔均出现病理性强化,其中１０例呈弥漫性,８例呈结节性,３例呈弥漫与结节混合性。弥漫性强化沿脑和脑干表面分布,并延伸入脑沟、脑池;结节性强化病灶数目１个或多个不等,直径０．２～３．０ｃｍ。病变见于基底脑池及相邻蛛网膜下腔者共１８例。伴室管膜结节性强化４例,天幕增厚强化１０例,脑积水１３例,合并脑内转移９例。结论增强ＣＴ和ＭＲＩ对病变的诊断具有重要临床意义,且ＭＲＩ优于ＣＴ。但两者在定性诊断上均有局限性。正确诊断有赖于结合临床资料和影像征象的综合分析     

MR imaging with Gd-DTPA in leptomeningeal spread of lymphoma

We describe the magnetic resonance (MR) plus Gd-diethylenetriamine pentaacetic acid (DTPA) findings in a patient with leptomeningeal spread of lymphoma. Gadolinium-DTPA aided in the diagnosis by offering additional information after noncontrast MR. Magnetic resonance with Gd-DTPA may well prove to be an important adjunct in the work-up of patients suspected of leptomeningeal spread of neoplasm.     

Diffuse testicular disease: sonographic features and significance

Sonographic findings in 26 patients with diffuse testicular disease were retrospectively analyzed for features to differentiate diffuse neoplasms from diffuse orchitis or infarct. Diffuse neoplasms were associated with moderate to marked enlargement, globular shape, lobulated contour, and heterogeneous texture of the testis; the epididymis and scrotal skin were normal. In diffuse inflammatory disease, the testis was mild to moderately enlarged, the oval shape and smooth contour were preserved, and the texture was generally homogeneous; the epididymis was often enlarged, and scrotal skin was almost always thickened.     

MR of leptomeningeal spinal and posterior fossa amyloid.

We report an unusual cause of leptomeningeal MR enhancement, amyloid, along the surfaces of the spinal cord and brain stem and in the spinal subarachnoid space, with sacral intradural and epidural deposition. Type I familial amyloid polyneuropathy may cause amyloid deposition along the leptomeninges of the spinal cord and brain in addition to the visceral organs and the peripheral somatic and autonomic nerves.