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.     

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 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.     

Gadopentetate dimeglumine-enhanced MR imaging in children following surgery for brain tumor: spectrum of meningeal findings

Gadopentetate dimeglumine-enhanced MR imaging was performed in 51 consecutive postoperative pediatric neurosurgical patients with a diagnosis of brain tumor. These studies were examined retrospectively to determine the spectrum of meningeal findings in this patient population. Patterns of enhancement were correlated with type of surgery, interval since surgery, clinical and CSF findings, and the use of radiation and steroid therapies. Normal postoperative meningeal findings include no meningeal enhancement or mild focal or diffuse dural enhancement. More moderate dural or subdural enhancement may be seen in clinically well children who have postsurgical subdural collections, or who have a remote history of serious meningeal disease (meningitis or subarachnoid hemorrhage). In all six cases in which nodular dural, leptomeningeal, or ependymal enhancement was seen, recurrent local tumor, leptomeningeal metastases, or infection were present. Leptomeningeal tumor or infection should be suspected if such patterns of enhancement are noted. Parameters that did not appear to affect the pattern of meningeal enhancement included type of surgery, interval since surgery, or therapeutic radiation.     

Spontaneous superficial parenchymal and leptomeningeal hemorrhage in term neonates

BACKGROUND AND PURPOSE: Intracranial hemorrhage in term neonates often results from asphyxia, obvious birth trauma, blood dyscrasia, or vascular malformation but may occur without an obvious inciting event. In this study, we review the clinical and neuroimaging features of healthy term neonates presenting with spontaneous superficial parenchymal and leptomeningeal (ie, subpial or subarachnoid) hemorrhage. METHODS: The clinical records and neuroimaging studies of seven term neonates with spontaneous superficial parenchymal and leptomeningeal hemorrhage were retrospectively reviewed. All underwent diffusion-weighted MR imaging and 6 underwent CT within 72 hours of birth. Magnetic susceptibility-weighted imaging was performed in five, MR angiography in two, and MR venography in two. Follow-up MR imaging was performed in one infant. Clinical follow-up was done in four patients. RESULTS: All neonates had normal birth weights and high 5-minute APGAR scores. All were delivered vaginally (one with forceps assistance, and one with vacuum assistance). No blood dyscrasias were noted. Within 36 hours after delivery, all neonates presented with apnea or seizures or both. Neuroimaging subsequently revealed superficial parenchymal and leptomeningeal hemorrhage. Four occurred in the anterior-inferior-lateral temporal lobe adjacent to the pterion. The remaining three were located in the parietal lobe, frontal lobe, and lateral temporal lobe under the squamosal suture. Decreased diffusion in parenchyma adjacent to the hemorrhage and overlying subcutaneous soft-tissue swelling were apparent in five patients. Susceptibility-weighted imaging showed no additional lesions. MR angiography and MR venography findings were normal. Follow-up MR imaging in one patient demonstrated encephalomalacia. Four patients with short-term clinical follow-up were neurologically normal. CONCLUSION: Spontaneous superficial parenchymal and leptomeningeal hemorrhage occurs in otherwise healthy term neonates. The hemorrhage is most often in the temporal lobe and in proximity to sutures, accompanied by overlying soft-tissue swelling and adjacent decreased diffusion. This pattern leads us to implicate local trauma with contusion or venous compression or occlusion in the development of these hemorrhages.     

Intracranial cryptococcosis in immunocompromised patients: CT and MR findings in 29 cases

CT and MR scans of 29 immunocompromised patients (28 with AIDS or ARC, one with diabetes mellitus) who had documented intracranial cryptococcal infection were reviewed retrospectively. All patients had CT studies; 26 received iodinated contrast agent. CT findings included normal results in nine of 29, atrophy only in 13 of 29, nonenhancing lesions in three of 29, enhancing lesions in two of 20, and foci of leptomeningeal calcification in two of 29. Ten patients had both CT and MR studies, and four received gadopentetate dimeglumine. Among these 10 patients, five had normal CT studies and one showed moderate central atrophy. All 10, however, had abnormal MR findings. We observed four patterns: (1) parenchymal cryptococcoma (3/10); (2) numerous clustered tiny foci that were hyperintense on T2-weighted images and non-enhancing on postcontrast T1-weighted images, located relatively symmetrically in the basal ganglia bilaterally and in midbrain, representing dilated Virchow-Robin spaces (4/10); (3) multiple miliary enhancing parenchymal and leptomeningeal nodules (1/10); and (4) a mixed pattern, consisting of dilated Virchow-Robin spaces with mixed lesions such as cryptococcoma and miliary nodules (2/10). In the group of six patients with dilated Virchow-Robin spaces (patterns 2 and 4), two received gadopentetate dimeglumine, but the Virchow-Robin space lesions did not enhance; among the remaining four patients, two received gadopentetate dimeglumine (one with pattern 1 and one with pattern 3) and the lesions did enhance. Three patients in our study subsequently died and autopsies were performed. The postmortem results revealed dilated Virchow-Robin spaces filled with fungi in the basal ganglia, which correlated well with MR findings.(ABSTRACT TRUNCATED AT 250 WORDS)     

Leptomeningeal metastasis: MR imaging

Seven patients with central nervous system neoplasia and leptomeningeal metastases, proved either at initial diagnosis or on follow-up with contrast material-enhanced computed tomography (CT), were evaluated with magnetic resonance (MR) imaging. In two patients, diffuse sulcal enhancement on CT scans was inapparent on T1- or T2-weighted MR images. Likewise, in four patients diffuse cisternal enhancement on CT scans was not identifiable with MR. Nodular or focal cisternal masses were identified with both CT and MR imaging in three patients; in two, however, MR imaging provided less information. Ependymal and subependymal metastases identified with CT (two patients) were indistinguishable on MR images from periventricular abnormalities of radiation therapy and/or hydrocephalus. These findings suggest that leptomeningeal metastasis may be so subtle or inapparent as to be overlooked with MR imaging alone. Thus, CT and MR imaging should be considered complementary techniques for initial diagnosis and follow-up of tumors with a propensity for leptomeningeal metastasis.     

MR增强后液体衰减反转恢复序列对脑转移瘤的诊断价值

目的 分析MR增强后液体衰减反转恢复(fluid attenuated inversion recovery,FLAIR)序列对脑转移瘤的诊断价值. 资料与方法 确诊恶性肿瘤可疑有脑转移患者159例.MR检查除常规平扫和增强外,在增强后加扫FLAIR序列,图像由3名有经验的放射科医师评估. 结果 58例有脑内转移,6例增强后FLAIR脑实质病灶数目显示较增强T1WI多,11例病灶强化较T1WI明显;在11例柔脑膜转移者中,7例病灶强化程度优于增强后T1WI. 结论 增强后FLAIR是增强后T1WI的有效补充,对脑内小病灶和脑膜病灶更敏感.     

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.     

Leptomeningeal metastases: MR evaluation

Forty patients with positive CSF cytology for subarachnoid dissemination of neoplasms were examined by magnetic resonance (MR) imaging for the detection of intracranial or intraspinal CSF metastases. The MR evidence of cerebral leptomeningeal metastases was noted in 12 of 54 unenhanced (22.2%) and 7 of 20 (35%) gadolinium-enhanced studies. However, in only 2 of the 20 (10%) gadolinium-enhanced scans did the enhanced brain images alone demonstrate the presence of CSF seeding. Four of 29 (13.8%) unenhanced studies of the spine and 6 of 16 (37.5%) gadolinium-enhanced spine studies were positive for neoplastic deposits on the spinal nerves or cord. Magnetic resonance without and with gadolinium enhancement was most likely to be positive in studies of patients with a non-CNS primary malignancy (16/51 = 31.4%) and least accurate with lymphoma or leukemia (1/18 = 5.6%). Although gadolinium administration increases the ability of MR to detect leptomeningeal metastases (particularly in the spine), the overall sensitivity of unenhanced and enhanced MR examinations is low (19.3 and 36.1%, respectively) in patients with proven cytological evidence of neoplastic seeding.     

颅内生殖细胞瘤转移的MRI表现

目的　探讨颅内生殖细胞瘤转移的MR影像学表现 ,为临床治疗方案的选择提供影像学依据。方法　结合文献资料 ,对10例具有转移灶的颅内生殖细胞瘤患者的临床与MRI资料进行分析。结果　 2 5例颅内生殖细胞瘤中的 10例发生转移 ,转移发生率 40 %,其增强MRI可表现为 :①软脑膜条索状增粗 ;②脑或脊髓表面的结节状信号 ,病变累及部位弥漫性肿胀 ,信号不均 ,脑沟消失 ;③肿瘤前部楔形缺损或三脑室后部“笔尖样”扩大 ;④室管膜下层片状或弥漫性高信号 ;⑤颅外转移征象等。结论　增强MRI能准确检测颅内生殖细胞瘤转移 ,为临床确立合理治疗方案提供有价值信息。     

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.     

Computed tomography of renal lymphoma

The CT studies of 29 patients with renal or perirenal lymphoma were retrospectively reviewed. Four patterns of disease were identified. Seventeen of 29 patients (59%) had bilateral renal masses. Only seven of these patients had associated enlarged retroperitoneal lymph nodes. Eight patients (28%) had single renal or perirenal lesions adjacent to or contiguous with bulky retroperitoneal lymphadenopathy. Three patients had infiltration of the perirenal space without significant renal parenchymal involvement, and one patient had a solitary renal mass. No patients in this series had diffuse involvement of the kidney without a focal mass. Renal involvement with lymphoma should be considered in any patient who develops multiple homogeneous solid renal or perirenal masses, even in the absence of other retroperitoneal disease.     

Magnetic resonance imaging of penile metastases: a report on five cases

Five cases of penile metastases are presented. Axial and sagittal T1-weighted and T2-weighted scans were performed in all patients. In some, coronal images were also obtained. The penile metastases were most often seen as discrete masses in the corpora cavernosa or corpus spongiosum. An atypical pattern of diffuse infiltration is also illustrated. Limitations of cavernosography, ultrasound (US) and computed tomography (CT) are discussed. The magnetic resonance (MR) features of penile metastases and possible role MR may have in the management of these patients are described.     

Diagnostic value of contrast-enhanced fluid-attenuated inversion recovery MR imaging of intracranial metastases

BACKGROUND AND PURPOSE: Postcontrast fluid-attenuated inversion recovery (FLAIR) imaging effectively depicts parenchymal and leptomeningeal metastases, as reported in limited patient groups. We compared postcontrast T1-weighted (T1W) and FLAIR imaging in a larger group. METHODS: Sixty-nine patients with known malignancy and suspected cranial metastases underwent axial FLAIR and spin-echo T1W imaging with and then without intravenous gadopentetate dimeglumine. Postcontrast images were compared for lesion conspicuity and enhancement, number of parenchymal metastases, and extension of leptomeningeal-cisternal metastases. RESULTS: Parenchymal metastases were demonstrated in 33 patients. Compared with T1W images, postcontrast FLAIR images showed more metastases in five patients, an equal number in 20, and fewer lesions in eight. Regarding lesion conspicuity, postcontrast FLAIR imaging was superior in five patients, equal in one, and inferior in 27. For enhancement, FLAIR imaging was superior in five, equal in five, and inferior in 23. Superior FLAIR results for lesion number, conspicuity, and enhancement were observed in the same five patients; in these patients, FLAIR imaging was performed as the second postcontrast sequence. Eleven patients had leptomeningeal-cisternal metastases; lesion conspicuity, extension, and enhancement were superior on postcontrast FLAIR images in eight. In five of eight patients, FLAIR imaging was performed as the second postcontrast sequence. Four patients had cranial-nerve metastases; in three, postcontrast FLAIR imaging was superior for lesion conspicuity and extension. In two of these patients, FLAIR imaging was the second postcontrast sequence. CONCLUSION: Postcontrast FLAIR imaging is a valuable adjunct to postcontrast T1W imaging. Precontrast and postcontrast FLAIR imaging effectively delineates parenchymal metastases, particularly leptomeningeal-cisternal and cranial-nerve metastases.     

颅内原发恶性肿瘤柔脑膜转移的MRI诊断

目的：探讨颅内原发恶性肿瘤柔脑膜转移的MR影像学特征,为临床提供早期诊断和治疗依据。方法：搜集33例诊断颅内原发恶性肿瘤柔脑膜转移惠者的MR扫描资料,扫描选用常规自旋回波脉冲序列,10例加扫液体衰减反转恢复脉冲序列,全部病例均行增强扫描。结果：平扫表现为不同范围脑池、脑沟和／或脑室变形、移位,结构模糊,其中28例伴有明显脑回肿胀．合并脑室壁不均匀增厚8例;合并蛛网膜下腔肿瘤结节9例,共发现结节17个,合并脑积水10例,部分病例上述表现合并存在。其中10例另选用液体衰减反转恢复脉冲序列扫描后,转移病灶轮廓显示较常规SE序列清晰,信号略高于TSE—T2WI。瘤体边缘与周围水肿难于分辨。增强扫描后脑内瘤体均明显增强,柔脑膜转移显示呈不同强化特征,8例尾征,14例线征,6例条索征及9例环征或结节征,少部分病例合并两种征象存在。结论：加深对颅内原发恶性肿瘤柔脑膜转移的MR影像特征的认识,选择适当的MR成像技术,提高脑膜病变的早期检出率,对临床选择治疗方案具有十分重要的意义。     

Lyme disease in childhood presenting as primary leptomeningeal enhancement without parenchymal findings on MR.

We report the MR appearance of a rare case of Lyme disease presenting as diffuse leptomeningeal enhancement in the absence of parenchymal lesions. In the appropriate clinical setting, one should consider Lyme disease in the differential diagnosis of meningeal enhancement.     

非脑膜瘤脑膜异常强化的MRI与病因对比研究

目的：分析不同脑膜病变的强化特征，探讨脑膜强化形式与病因诊断的关系。材料与方法：回顾性分析资料完整的异常脑膜强化２６例，根据脑膜受累层次、范围将强化形式分为四种：（１）弥漫性脑膜强化；（２）弥漫性硬膜强化；（３）弥漫性软膜强化；（４）局限性硬膜强化。依病因不同将脑膜病变分为三组：（１）肿瘤组；（２）炎症组；（３）反应组。结果：２６例中，肿瘤组８例，其中弥漫性硬膜、软膜强化各３例，弥漫性脑膜强化、局限性硬膜强化各１例。炎症组８例，弥漫性软膜强化７例，局限性硬膜强化１例。反应组１０例，８例呈局限性硬膜强化，２例呈弥漫性硬膜强化。结论：不同的脑膜病变可表现不同的强化特征，但离开临床，仅根据强化特征尚难做出定性诊断。     

Gallbladder wall thickening: MR imaging and pathologic correlation with emphasis on layered pattern

The aim of this study was to correlate MR findings of gallbladder wall thickening with pathologic findings on the basis of the layered pattern and to evaluate the diagnostic value of MR imaging in gallbladder disease. We retrospectively evaluated the source images of HASTE sequences for MR cholangiography in 144 patients with gallbladder wall thickening. The layered pattern of thickened wall was classified into four patterns. Type 1 shows two layers with a thin hypointense inner layer and thick hyperintense outer layer. Type 2 has two layers of ill-defined margin. Type 3 shows multiple hyperintense cystic spaces in the wall. Type 4 shows diffuse nodular thickening without layering. MR findings of a layered pattern of thickened gallbladder were well correlated with histopathology. Chronic cholecystitis matched to type 1, acute cholecystitis corresponded to type 2, adenomyomatosis showed type 3, and the gallbladder carcinomas showed type 4. All four layered patterns were associated with PPV of 73% or greater, sensitivity of 92% or greater and specificity of 95% or greater. Our results indicate that MR findings of gallbladder wall thickening are characteristic in each entity and correlate well with pathologic findings. The classification of the layered pattern may be valuable for interpreting thickened gallbladder wall.     

Intracranial leptomeningeal metastases: comparison of depiction at FLAIR and contrast-enhanced MR imaging

PURPOSE: To compare contrast material-enhanced T1-weighted and fluid-attenuated inversion-recovery (FLAIR) magnetic resonance (MR) images in depicting leptomeningeal metastases. MATERIALS AND METHODS: Malignant lesions detected at cytologic examination of cerebrospinal fluid in 70 patients were reviewed. There were 58 studies in which both FLAIR and contrast-enhanced T1-weighted spin-echo MR images were available. A senior neuroradiologist reviewed the images from each sequence individually and separately for signs of leptomeningeal metastases and assigned a diagnostic rating of positive, indeterminate, or negative. RESULTS: Leptomeningeal metastases were depicted in 38 cases on contrast-enhanced T1-weighted spin-echo images and in 20 cases on FLAIR images. In three cases, leptomeningeal metastases were detected by using only FLAIR images. In 20 cases, leptomeningeal metastases were detected by using only contrast-enhanced T1-weighted spin-echo images. FLAIR imaging has a sensitivity of 34% for cytologically proved leptomeningeal metastases. Gadolinium-enhanced MR imaging has a sensitivity of 66%. CONCLUSION: Used alone, contrast-enhanced T1-weighted images are better than FLAIR images for detecting leptomeningeal metastases. This is particularly true for cases in which leptomeningeal metastases manifest primarily or solely as cranial nerve involvement.