Dural invasion of meningiomas adjacent to the tumor margin on Gd-DTPA-enhanced MR images: histopathologic correlation

In intracranial meningiomas a flat, contrast-enhancing, dural structure adjacent to the tumor can occasionally be observed on gadolinium-DTPA-enhanced MR images. We wished to evaluate whether there is a correlation between MR images and meningeal invasion of intracranial meningiomas. The study included 54 patients with intracranial meningioma and the meningeal sign. MR studies included T2-weighted and gadolinium-DTPA-enhanced T1-weighted images in axial, coronal, and sagittal planes. Histopathologic examinations were done on the meningiomas adjacent to the dura mater. The meningeal sign on MRI was observed from 2 up to 35 mm from the main tumor mass in 31 (57 %) of the 54 patients. In 20 of these 31 the histopathologic examination showed tumor invasion, while 11 patients had no tumor invasion but tissue proliferation, hypervascularity, and vascular dilatation. Seven of the 23 meningiomas without the meningeal sign had histologically proven infiltration of the adjacent dura. MR imaging is not able to determine definitive whether or not there is dural infiltration of the meningiomas. In conclusion, resection of the tumor with a wide margin is necessary to achieve complete excision of meningioma and to avoid recurrence. Received 23 July 1997; Revision received 10 October 1997; Accepted 17 October 1997     

Prominent dural enhancement adjacent to nonmeningiomatous malignant lesions on contrast-enhanced MR images

Prominent dural enhancement was noted in 10 (16%) of 61 superficial malignant intracranial tumors studied with contrast-enhanced MR imaging during a 2-year period. Included were six glioblastomas, three parenchymal metastases, and one case of dural metastasis. Seven patients had surgery. In four, there was extensive leptomeningeal invasion in the center of the lesion. In two of these lesions there was firm attachment of the center of the tumor to the dura, but without dural invasion despite extensive external carotid artery supply to the tumor in one case. In two cases the overlying dura was normal, and there was no leptomeningeal tumoral invasion. In the case of dural metastasis, huge nodular lesions were present along the inner aspect of the dura. In none of the cases did prominent dural enhancement adjacent to the tumor correspond with tumoral invasion or extension to the dura. Prominent dural enhancement on contrast-enhanced MR images appears to be much less frequent in malignant tumor than in meningioma, where it is seen in up to 60% of the cases. We believe this finding is more likely to represent reactive changes of the dura than tumoral invasion.     

Contrast-enhanced MR images in patients with meningioma: importance of enhancement of the dura adjacent to the tumor

Linear enhancement (flare sign) along the dura mater that was continuous with or emanated from the dural margin of meningiomas was frequently observed on contrast-enhanced MR images obtained in 18 patients with intracranial meningiomas (surgically proved). Preoperative MR studies obtained at 1.5 T after administration of gadopentetate dimeglumine were reviewed retrospectively to determine the clinical significance of this sign. Thirteen (72%) of the 18 meningiomas exhibited the finding adjacent to the dural attachments. Four meningiomas of the cerebellopontine angle showed enhancement along the internal auditory canals. Three specimens of the dura adjacent to the tumor in different patients with this finding revealed proliferation of connective tissues abounding with vessels along the dura without definite tumor invasion. The flare sign is thought to be a common finding of meningiomas on contrast-enhanced MR images obtained with high-resolution sequences, and it is observable without tumor invasion. This sign in the cerebellopontine angle should not be misinterpreted as enhancement of acoustic schwannomas.     

Cerebral astrocytomas: histopathologic correlation of MR and CT contrast enhancement with stereotactic biopsy

Gadolinium-labeled diethylenetriaminepentaacetic acid was used as a contrast agent for stereotactic magnetic resonance (MR) imaging in six selected patients with brain tumors who underwent stereotactic biopsy. Regions of contrast enhancement demonstrated by computed tomography (CT) and MR imaging in four of the six patients correlated with areas of malignant neovascularity and endothelial proliferation within solid tumor. Radiation necrosis produced contrast enhancement indistinguishable from that of recurrent neoplasm. Isolated tumor cells within intact white matter were identified in biopsy specimens obtained outside of regions that were depicted as abnormal by contrast material-enhanced CT, as well as by precontrast and postcontrast T1- and T2-weighted MR images.     

Perilesional enhancement of hepatic metastases: correlation between MR imaging and histopathologic findings-initial observations

PURPOSE: To correlate perilesional enhancement on gadolinium-enhanced magnetic resonance (MR) images with histopathologic findings in patients with hepatic metastases. MATERIALS AND METHODS: In seven patients with histopathologically proved hepatic metastases, MR images obtained before and early and late after the administration of gadopentetate dimeglumine were retrospectively evaluated for perilesional enhancement. The thickness of hepatic parenchyma with intense perilesional enhancement was calculated. The thickness of the histologic tumor border (the zone separating the outermost border of the tumor nodule from the surrounding hepatic parenchyma) also was measured. RESULTS: In three patients, early gadolinium-enhanced images showed prominent perilesional enhancement, which correlated with a thick tumor border containing peritumoral desmoplastic reaction, peritumoral inflammation, and vascular proliferation at histopathologic examination. In one patient, mild perilesional enhancement was shown. At histopathologic examination, the lesion periphery showed moderate peritumoral changes. In the remaining three patients, no perilesional enhancement was observed, and at histopathologic examination there was a thin tumor border that contained minimal to mild perilesional changes. The thickness of hepatic parenchyma with intense perilesional enhancement on early gadolinium-enhanced images showed a strong positive correlation with tumor border thickness at histopathologic examination (r = 0.99). CONCLUSION: Intense perilesional enhancement of metastases on early gadolinium-enhanced MR images correlates with histopathologic hepatic parenchymal changes, which include peritumoral desmoplastic reaction, inflammatory cell infiltration, and vascular proliferation.     

Meninges: benign postoperative enhancement on MR images

In a group of 20 postcraniotomy patients who underwent magnetic resonance imaging performed with gadopentetate dimeglumine, 16 (80%) had nonneoplastic meningeal enhancement. This was seen as either enhancement of a local dural membrane or generalized meningeal enhancement. In a control group of 23 patients, only three (13%) had similar findings. The authors believe that postcraniotomy meningeal enhancement is most likely the result of a local inflammatory process or a diffuse chemical arachnoiditis caused by bleeding into the subarachnoid space at the time of surgery. The finding does not necessarily indicate leptomeningeal tumor spread or infection.     

Cerebral aspergillosis: MR imaging and histopathologic correlation.

The authors report a case of intracranial aspergillosis secondary to immunosuppression. Signal intensity changes in the lesion on brain MR are compared with gross and histopathologic findings at autopsy. A peripheral ring of low signal intensity relates to a dense population of Aspergillus hyphal elements and small areas of hemorrhage. CT findings are included for comparison.     

Calvarial and skull base metastases: comparison of nonenhanced and Gd-DTPA-enhanced MR images

Fourteen patients with calvarial metastases were studied with magnetic resonance (MR) imaging before and after intravenous administration of gadolinium diethylenetriamine-pentaacetic acid (DTPA) to evaluate the utility of contrast material enhancement for the detection of calvarial metastatic tumor. MR imaging was also performed before and after enhancement in 60 patients for reasons other than evaluation of metastases or calvarial tumor, to determine the apperance of the normal calvaria with enhancement. The normal pattern of fat distribution in the diploic space was typically symmetric. Except for enhancement of diploic veins and meninges near pacchionian granulations, the normal diploic space did not enhance. Calvarial metastases typically enhanced with Gd-DTPA. Enhanced MR images were superior to nonenhanced studies for detecting subtle intradiploic metastases but were inferior to nonenhanced studies for detecting tumor extension into fat-containing areas. Careful comparison of nonenhanced and enhanced MR images is required for complete evaluation of lesions affecting the calvaria and skull base.     

Perilesional hyperintense rim of malignant hepatic tumors on ferumoxide-enhanced T1-weighted gradient-echo MR images: correlation between MR imaging and histopathologic findings

PURPOSE: To correlate the perilesional hyperintense rim of malignant hepatic tumors seen on ferumoxide-enhanced T1-weighted gradient-echo (GE) MR images with histopathologic findings. MATERIALS AND METHODS: In 13 tumors in 12 patients, T1-weighted GE images (TE of 1.4 msec, flip angle of 90 degrees) obtained after IV administration of ferumoxide were evaluated. MR imaging was initiated within one hour of the completion of ferumoxide administration. Surgical resection for tumors was performed within an interval of two weeks of the MR imaging. Resected specimens were histopathologically examined for peritumoral sinusoidal congestion, desmoplastic reaction, compressed hepatic parenchyma, lymphocytic infiltration, and vascular proliferation. RESULTS: In twelve tumors (92%), prominently (N = 2), moderately (N = 5), and mildly to minimally (N = 5), a perilesional hyperintense rim was observed. Among histopathologic findings, the degree of peritumoral sinusoidal congestion correlated (R =.75, P <.04) with the degree of perilesional hyperintense rim. The thickness of the perilesional hyperintense rim showed a moderate positive correlation (R =.65, P <.02) with the thickness of peritumoral area with sinusoidal congestion. CONCLUSION: Perilesional hyperintense rim of malignant hepatic tumors on ferumoxide-enhanced T1-weighted GE images may correlate with sinusoidal congestion surrounding malignant hepatic tumors.     

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。     

Retinoblastoma: Abnormal gadolinium enhancement of anterior segment of eyes at MR imaging with clinical and histopathologic correlation

PURPOSE: To evaluate abnormal gadolinium enhancement of the anterior segment of eyes harboring retinoblastoma at magnetic resonance (MR) imaging and correlate this finding with clinical and histopathologic information. MATERIALS AND METHODS: Three neuroradiologists examined 46 eyes with 34 retinoblastomas in 25 children on gadolinium-enhanced T1-weighted orbital MR images obtained shortly after contrast material injection for evidence of abnormally high signal intensity in the anterior segment. Twenty-two of the 34 affected eyes were enucleated, and six of these 22 eyes were treated with preenucleation adjuvant therapy. Thus, correlation of the clinical, MR imaging, and histopathologic findings in 16 eyes was performed. Statistical analysis was performed with nonparametric methods (Fisher exact test). P <.05 indicated a statistically significant difference. RESULTS: Fourteen of the 34 affected eyes showed abnormal gadolinium enhancement of the anterior segment. Regarding the 16 eyes evaluated for statistical analysis, a significant correlation (P =.011) between abnormal gadolinium enhancement of the anterior segment and histopathologically documented optic nerve infiltration was noted. A trend toward an association between abnormal enhancement and elevated intraocular pressure (P =.215), tumor growth beyond the equator at MR imaging (P =.125), and histopathologically proved iris neoangiogenesis (P =.182) also was noted. Histopathologic evidence of optic nerve and/or choroid infiltration correlated significantly (P =.001; sensitivity, 100% [nine of nine eyes]; specificity, 86% [six of seven eyes]) with abnormal enhancement. CONCLUSION: Abnormal gadolinium enhancement of the anterior segments of eyes harboring retinoblastoma seems to indicate more aggressive tumor behavior.     

Gorham disease: correlation of MR findings with histopathologic changes

Gorham disease is a rare disorder of unknown etiology characterized by bone destruction and abnormal proliferation of thin-walled vascular channels including lymphatic capillaries. Starting monocentrically in a single bone, the angiomatous masses in this disease extend to adjacent bones and soft tissues without respecting articular barriers. Herein we report a case of Gorham disease with its MR and histopathologic appearance. Received 26 May 1997; Revised 8 October 1997; Accepted 17 February 1998     

Human brain infarcts: Gd-DTPA-enhanced MR imaging

During Food and Drug Administration phase II and III clinical trials for gadolinium DTPA, the paramagnetic agent was used to study 11 patients with 20 subacute and chronic cerebral infarcts. Five patients had numerous periventricular and deep white-matter lesions, probably due to chronic ischemic disease. Magnetic resonance (MR) imaging was performed 4-30 days after the ictus, preceded by computed tomography (CT) in all but one case. In most cases, the nonenhanced spin-echo (SE) images, obtained at 500-msec repetition times and 30-msec echo times, failed to demonstrate the infarct, and in general the gadolinium-enhanced SE 500/30 images matched the contrast material-enhanced CT scans in pattern. Periventricular lesions and small, deep, white-matter infarcts that were chronic and asymptomatic were not enhanced by gadolinium MR. However, three small, symptomatic capsular and brain-stem infarcts showed definite enhancement. Usually the enhancement was visible at 3 minutes, increasing to a peak at 30 minutes. At 55 minutes, the enhancement increased in the medium-aged infarcts (8-14 days), while it decreased in the late infarcts (15-30 days). The T2 relaxation time-weighted pulse sequences were most sensitive for demonstrating all infarcts, but without the aid of a contrast agent, they were frequently poor in specificity.     

Hepatic metastases: liposomal Gd-DTPA-enhanced MR imaging

Liposomal gadolinium diethylenetriaminepentaacetic acid (DTPA) encapsulated within 70- and 400-nm vesicles was tested as a contrast agent for magnetic resonance (MR) imaging of the liver in rats with hepatic metastases. Liposomal Gd-DTPA caused significant improvement in contrast between liver and tumor (P less than .005) on T1-weighted MR images. Smaller 70-nm liposomal Gd-DTPA vesicles caused greater contrast enhancement, reflecting the larger surface-area-to-volume ratio of the smaller vesicles. Liposomal Gd-DTPA-enhanced images permitted significant improvement in metastasis detection by five blinded radiologists (P less than .005). By comparison, free Gd-DTPA without liposomes caused a statistically significant reduction in contrast between tumor and liver and reduced lesion detection (P less than .01). Liposomal Gd-DTPA also resulted in sustained vascular enhancement for 1 hour after administration. The results suggest that paramagnetic liposomes may become a useful MR imaging contrast agent.     

Cerebral Erdheim-Chester disease: persistent enhancement with Gd-DTPA on MR images

A case of Erdheim-Chester disease with intracerebral masses containing characteristic lipid-laden histiocytes is presented. These unusual lesions remained enhanced on magnetic resonance images obtained 8 days after injection of gadolinium diethylenetriaminepentaacetic acid (DTPA) dimeglumine. Chemical analysis of a biopsy specimen revealed a high concentration of gadolinium. Findings suggest that the Gd-DTPA complex or possibly a gadolinium-containing metabolite may be retained for extended periods in this unusual type of histiocytic lesion.