Meningioangiomatosis: CT and MR findings.

Meningioangiomatosis (MA) is a rare hamartomatous lesion of the cerebral cortex; to date only 18 cases with imaging findings have been reported in the English literature. The origin of MA is probably malformative, with possible association with neurofibromatosis. These lesions frequently cause seizures in young patients. We report two new cases seen at our institution and present their CT and MR findings clearly illustrating MA cortex infiltration. Gd-DTPA used in one of the two cases failed to cause enhancement.     

Malignant nerve-sheath neoplasms in neurofibromatosis: distinction from benign tumors by using imaging techniques

Malignant peripheral nerve-sheath neoplasms frequently complicate neurofibromatosis causing pain, enlarging masses, or neurologic deficits. However, similar findings sometimes also occur with benign nerve neoplasms. Our study was done retrospectively to determine if imaging techniques can differentiate malignant from benign nerve tumors in neurofibromatosis. Eight patients with symptomatic neoplasms (three benign, five malignant) were studied by CT in eight, MR in six, and 67Ga-citrate scintigraphy in seven. Uptake of 67Ga occurred in all five malignant lesions but not in two benign neoplasms studied. On CT or MR, all eight lesions, including three benign neoplasms, showed inhomogeneities. Of five lesions with irregular, infiltrative margins on CT or MR, four were malignant and one was benign. Of three lesions with smooth margins, one was malignant and two were benign. One malignant neoplasm caused irregular bone destruction. Accordingly, CT and MR could not generally distinguish malignant from benign lesions with certainty. However, both CT and MR provided structural delineation to help surgical planning for both types of lesion. 67Ga scintigraphy appears promising as a screening technique to identify lesions with malignant degeneration in patients with neurofibromatosis. Any area of abnormal radiogallium uptake suggests malignancy warranting further evaluation by CT or MR. Biopsy of any questionable lesion is essential.     

Imaging of Sturge-Weber syndrome: cranial CT and MR findings

Sturge-Weber syndrome (SWS) is a phakomatosis characterized by vascular nevus flammeus, leptomeningeal venous angiomatosis, seizures, dementia, hemiplegia, hemianopsia, and glaucoma. Various imaging findings (gyriform calcification, atrophy of the ipsilateral hemisphere, leptomeningeal enhancement, ipsilateral choroid plexus enlargement, thickened calvarium, enlargement of paranasal sinuses and mastoid air cells, enlargement of deep veins, and white matter change adjacent to leptomeningeal enhancement) are seen in SWS. We examined the efficacy of CT and MR imaging in making the diagnosis in 14 patients. All patients underwent CT and MRI, and 11 of 14 patients underwent contrast-enhanced MRI. The most specific finding was leptomeningeal enhancement. Gyriform calcification, atrophy of the ipsilateral hemisphere, and ipsilateral chroid plexus enlargement were seen at high frequencies. Thickened calvarium was more frequent in adult patients. Enlargement of paranasal sinuses and mastoid air cells, enlargement of deep veins, and white matter change adjacent to leptomeningeal enhancement were seen in some (3-5) patients. A combination of findings of plain CT and MRI (including postcontrast MRI and MR venography) are useful for diagnosing SWS.     

Sporadic meningioangiomatosis: imaging findings with histopathologic correlations in seven patients

Introduction

Meningioangiomatosis (MA) is a rare benign cerebral lesion. We aimed to evaluate the CT and MR features of sporadic MA, with a focus on the correlation between imaging and histopathologic findings.

Methods

CT (n?=?7) and MR (n?=?8) images of eight patients (6 men and 2 women; mean age, 12.8 years; range, 4–22 years) with pathologically proven MA were retrospectively reviewed. After dividing the MA lesions according to their distribution into cortical and subcortical white matter components, the morphologic characteristics were analyzed and correlated with histopathologic findings in seven patients.

Results

CT and MR images showed cortical (n?=?4, 50 %) and subcortical white matter (n?=?7, 88 %) components of MA. All four cortical components revealed hyperattenuation on CT scan and T1 isointensity/T2 hypointensity on MR images, whereas subcortical white matter components showed hypoattenuation on CT scan and T1 hypointensity/T2 hyperintensity on MR images. Two cortical components (25 %) demonstrated enhancement and one subcortical white matter component demonstrated cystic change. Seven cases were available for imaging-histopathologic correlation. In all seven cases, the cortex was involved by MA and six patients (86 %) showed subcortical white matter involvement by MA. There were excellent correlations between the imaging and histopathologic findings in subcortical white matter components, and the accuracy was 100 % (seven of seven); whereas there were poor correlations in cortical components, and the accuracy was 43 % (three of seven).

Conclusions

The cerebral cortex and subcortical white matter were concomitantly involved by MA. Subcortical white matter components of MA were more apparent than cortical components on CT and MR imaging.     

Craniocervical manifestations of neurofibromatosis: MR versus CT studies

Craniocervical manifestations of neurofibromatosis on magnetic resonance (MR) imaging are described in three patients and compared with those on CT. Using MR, intracranial gliomas, schwannomas, and neurofibromas were detected as well as with CT. In addition, a brain stem lesion that was not visualized on CT and a cervical cord lesion that was not suspected clinically were diagnosed with MR. Taking into account the noninvasive nature of MR, we believe that this technique should be the primary imaging modality for screening and follow-up studies in patients with known or suspected neurofibromatosis.     

Renal lesion characterization with gadolinium-enhanced MR imaging: efficacy and safety in patients with renal insufficiency

Five patients with renal insufficiency were studied with T1-weighted magnetic resonance (MR) imaging before and after intravenous administration of gadopentetate dimeglumine (0.1 mmol/kg) to characterize renal lesions that were detected with nonenhanced computed tomography (CT) and were considered indeterminate. Four patients demonstrated renal lesions that enhanced after gadolinium administration. A total of five lesions in these four patients were surgically resected and found to be renal cell carcinoma at pathologic examination. The fifth patient was spared surgery because a hyperattenuated lesion noted at nonenhanced CT did not enhance with intravenous gadolinium, indicating a benign cyst. Five incidentally occurring benign cysts removed at the time of nephrectomy in two of the patients did not demonstrate enhancement with gadolinium on MR images. Serial serum creatine levels were obtained before and after gadolinium administration in all patients; no changes were noted after gadolinium administration. Gadolinium-enhanced MR imaging is an effective method for characterizing renal lesions in patients with renal insufficiency. At the usual dosage, there appears to be no nephrotoxic reaction in these patients.     

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.     

鼻窦和颞骨成骨细胞瘤CT和MRI诊断

目的探讨鼻窦和颞骨成骨细胞瘤CT和MRI表现，提高其诊断准确性。方法回顾性分析8例经病理证实的鼻窦和颞骨成骨细胞瘤的影像学资料，分析其CT和MRI表现。结果6例为良性成骨细胞瘤，2例为侵袭性成骨细胞瘤；发生于鼻窦者6例，颞骨者2例。CT表现：良性成骨细胞瘤边界清楚，圆形2例、椭圆形4例，周边伴有完整的骨壳，病灶内见点状、结节状、条状钙化或骨化，压迫邻近的结构；侵袭性成骨细胞瘤部分边界模糊，形态不规整，骨壳不完整，外周可见软组织肿块，内伴有不规则形的钙化或骨化，侵犯邻近结构。MRI表现：与脑实质比较，T1WI为等信号者4例，低信号者2例，T2WI信号不均匀，但病灶内部均见数量不一的极低信号影，对应CT上钙化或骨化区；4例骨壳在T1WI和T2WI均表现为低信号环，1例骨壳仅在T2WI显示低信号，1例骨壳在T1WI和T2WI均难以显示；增强后扫描呈中至显著强化，良性为较均匀强化，而侵袭性为不均匀强化；邻近脑膜可见不同程度强化，良性较均匀，侵袭性不规则且范围更大。结论CT是该病诊断和鉴别诊断的主要影像检查方法，MI可更清楚、准确显示病变侵犯的范围，为治疗提供可靠依据，可作为1种补充的影像检查方法。     

MR and CT imaging of 24 pleomorphic xanthoastrocytomas (PXA) and a review of the literature

INTRODUCTION: The aim of our study was to review the imaging appearance of PXA, a rare and usually low-grade, astrocytic tumor that typically occurs in young adults. METHODS: The clinical presentation, location and imaging findings on CT (n = 15) and MR (n = 18) of 24 pathologically confirmed PXA were retrospectively reviewed. Two morphologic patterns were defined according to imaging features. The Mann-Whitney U-test was used for statistical analysis of the data. RESULTS: All the neoplasms were supratentorial and superficial in location with obvious leptomeningeal contact in 22 patients, although leptomeningeal enhancement was demonstrated in only 3. Common locations were temporal (42%), frontal (33%) and parietal (21%), and more than one lobe was involved in 21% of patients. On CT without contrast enhancement, PXA was an iso- or hypoattenuating mass, and calcification was seen in six tumors and inner table remodeling was seen in three patients younger than 12 years. On MR, the solid component of PXA was isointense relative to gray matter on T1-weighted images, hyperintense on T2-weighted images in more than 90% and enhanced intensely following intravenous contrast material administration. Cystic areas showed hyperintensity relative to CSF. Two imaging patterns were differentiated: first a cystic mass containing a mural nodule (70%) and second a predominantly solid mass that may show cystic changes (30%). CONCLUSION: The most consistent imaging features of PXA were a superficial location, leptomeningeal contact, and enhancement of the solid component. Apart from the classical PXA appearance of a cystic lesion with an enhancing mural nodule, a second pattern consisting of a predominantly solid mass was recognized.     

Chronic seizure disorders: contribution of MR imaging when CT is normal

One hundred consecutive patients with complex partial seizures were studied by magnetic resonance (MR) imaging and computed tomography (CT). Thirty-four patients had seizures of more than 5 years' duration, yet neurologic examinations and previous pre- and postinfusion CT scans had been normal. MR imaging demonstrated surgical lesions of potentially therapeutic significance in four of these 34 patients. Two patients underwent surgery with removal of a thrombosed arteriovenous malformation and a glioma. Although CT has been found to detect structural abnormalities, its yield of therapeutically significant abnormalities has been low.     

Soft-tissue tumors: MR imaging

We evaluated the suspected soft-tissue masses of 33 patients using magnetic resonance (MR) imaging. Thirty-two masses were defined, of which ten were malignant and 22 were benign. Specific characteristics that would allow us to distinguish the benign lesions from the malignant ones could not be identified on MR imaging. Lesions located within muscles or in the intramuscular septa were best seen with T2-weighted imaging sequences; those located within the subcutaneous fat were best outlined with T1-weighted imaging sequences. Both imaging sequences were necessary to provide the complete representation of the extent of the mass. We performed comparison studies using computed tomography (CT) in 24 of the cases. Of 92 possible comparisons and in four categories MR imaging yielded results that were superior to those obtained by CT scanning in 30 instances, equaled the results obtained by CT scanning in 62 instances, but never yielded results inferior to those obtained by CT scanning. However, MR imaging failed to demonstrate soft-tissue calcification and soft-tissue gas in one case each.     

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.     

MR imaging and CT in three cases of Sturge-Weber syndrome: prospective comparison

Three patients with Sturge-Weber syndrome (5 months, 6 years, and 17 years old) were studied prospectively with MR imaging and CT of the brain. Both techniques demonstrated parenchymal volume loss, choroid plexus enlargement, calvarial hemiatrophy, and proptosis. In regions of parenchymal volume loss, MR alone demonstrated thickened cortex with decreased convolutions and abnormal white matter. A focal thalamic lesion and prominent medullary and subependymal veins were also shown better by MR. However, CT definitively demonstrated the characteristic cortical calcification, while T2-weighted MR images detected only smaller, nonspecific foci of hypointense signal. MR and CT are complementary in the evaluation of Sturge-Weber syndrome.     

Computed tomography and magnetic resonance imaging findings of solitary fibrous tumors in the pelvis: Correlation with histopathological findings

Objective

We aimed to analyze the computed tomography (CT) and magnetic resonance imaging (MRI) findings of pelvic solitary fibrous tumors (SFTs) and to improve the diagnostic efficacy for such tumors.

Methods

Six cases of pelvic SFTs confirmed by histopathology were analyzed retrospectively. Of the 6 patients, 4 had undergone CT scanning, and 2 had undergone magnetic resonance imaging. All the patients had undergone unenhanced and contrast-enhanced examinations, and 2 had also undergone dynamic CT enhancement examination. Image characteristics such as shape, size, number, edge, attenuation or intensity for each lesion before and after contrast enhancement were analyzed and compared with the pathomorphology of the tumors.

Results

All the 6 cases showed oval or rounded and well-defined masses. Unenhanced CT images showed heterogeneous masses with patchy, necrotic foci in 3 cases and homogeneous mass in 1 case. None of the tumors showed calcification. Contrast-enhanced CT images showed marked, heterogeneous enhancement in the first and second cases. Dynamic enhancement scan demonstrated mild homogeneous enhancement in the third case and mild prolonged, delayed enhancement and washout in the fourth case. T1-weighted MR images showed heterogeneous mild hypointense lesion with linear hyperintensity in 1 case, and homogeneous isointensity in the other. T2-weighted images showed heterogeneous mixed intensity in 1 case and mostly hyperintensive lesion with hypointense foci in another case. A case showed marked heterogeneous enhancement and another showed marked homogeneous enhancement on contrast-enhanced T1-weighted images.

Conclusion

Radiological findings of pelvic SFTs are variable and nonspecific. However, a well-defined, ovoid or rounded mass with hypointense on MR T2-weighted images and variable enhancement on CT and MR images may suggest the diagnosis of SFTs. Pelvic SFTs should be included in the differential diagnosis of regional tumors.     

Gd-DTPA-enhanced MR imaging of leptomeningeal spread of primary intracranial CNS tumor in children

Three children with known primary brain neoplasms and leptomeningeal disease were evaluated with MR imaging. Two of the patients had medulloblastoma and one had pineoblastoma. The presence of leptomeningeal tumor spread was established by positive CSF cytopathology in conjunction with compatible contrast-enhanced CT findings. Contrast-enhanced CT, nonenhanced MR, and Gd-DTPA-enhanced MR studies were then compared. In two cases, leptomeningeal lesions were seen better with Gd-DTPA-enhanced MR than with contrast-enhanced CT. In all three cases, Gd-DTPA MR imaging revealed lesions that were not identified on noncontrast MR. Gd-DTPA-enhanced MR imaging is useful when searching for intracranial leptomeningeal tumor deposits in pediatric patients at risk for this condition.     

Spinal abnormalities in pediatric patients: MR imaging findings compared with clinical, myelographic, and surgical findings

Eighty-one pediatric patients with a variety of spinal disorders, including suspected dysrhaphism, scoliosis, neoplasia, and neurofibromatosis, underwent magnetic resonance (MR) imaging. The results were retrospectively compared with those of myelography followed by computed tomography (CT) and surgery. In patients with dysrhaphism, most abnormalities, including hydromyelia, inclusion tumors, and sites of cord tether, were demonstrated with MR imaging. Diastematomyelia and small hydromyelic cavities were indistinguishable on routine coronal and sagittal T1-weighted images; axial images with T2 weighting were optimal for this differentiation. MR imaging did not enable direct visualization of a thickened filum or evaluation of tethering with a thin, dorsally positioned neural placode. Congenital or severe scoliosis required lengthy studies with multiple planes of imaging or myelography and CT. Milder curvatures were readily evaluated with MR imaging, and neoplastic lesions, with the exception of intrathecal tumor seeding, were adequately defined.     

Pediatric choroid plexus neoplasms: MR, CT, and pathologic correlation

Choroid plexus papillomas are rare, constituting approximately 0.5% of all intracranial neoplasms. Four benign choroid plexus papillomas and one choroid plexus carcinoma were retrospectively reviewed in patients aged 4-20 months who had been examined with magnetic resonance (MR) imaging with a field strength of 0.5 T or 1.0 T and with computed tomography (CT) before and after the administration of contrast material. In general, the tumors were of intermediate signal intensity on T1-weighted images and of either intermediate or increased signal intensity (T2 lengthening) with T2 weighting. All demonstrated variable areas of internal signal void interpreted as signifying regional blood flow, calcification, or old hemorrhage. CT findings included relatively uniform contrast enhancement. Microscopic pathologic changes of the benign lesions mimicked the appearance of normal choroid plexus and confirmed the highly vascular nature of these tumors. MR imaging, with its high-resolution multiplanar techniques, offers direct visualization of these lesions in relation to normal anatomy and better discrimination and confirmation of their intraventricular location, facilitating surgery and postoperative follow-up.     

PET, CT, and MR imaging in cerebrovascular disease

Forty-five patients with cerebrovascular disease (single and multiple infarcts, intracerebral hemorrhages) were examined with X-ray CT, magnetic resonance (MR) imaging, and positron emission tomography (PET). In six patients with acute infarcts repeat measurements with all techniques were performed after 2 weeks. Magnetic resonance and PET were more sensitive in the detection of ischemic lesions than X-ray CT. With PET, functional disturbances could be demonstrated even in two cases where CT and MR were normal, while the latter techniques were superior in exactly localizing a lesion. Changes in lesion appearance with time were observed with all techniques, and the pathophysiologically important phenomena of hyperperfusion or hypermetabolism were documented in four infarcts with PET.     

Resective surgery for intractable epilepsy in children: radiologic evaluation.

Epilepsy surgery is gaining popularity for the treatment of children with intractable seizures in whom either a focal or extensive unilateral structural brain lesion is demonstrated. We evaluated the pre- and postoperative imaging findings in 29 patients (aged 22 days to 19 years) who underwent hemispherectomies, 12 total and 17 subtotal. Pathologic correlation was obtained in all cases. Preoperatively, positron emission tomography and electroencephalography demonstrated abnormalities in all of the 28 children studied, but frequently could not characterize the lesion. CT or MR or both demonstrated focal or unilateral lesions in only 19 of these but gave additional information regarding the nature of the lesion. Preoperative angiographic findings were abnormal in five of 17 patients studied and were particularly useful in the evaluation of the extent of abnormality in patients with Sturge-Weber syndrome. Postoperatively, CT and MR demonstrated early complications such as the development of epidural blood and fluid collections, parenchymal hemorrhage, infection, and early hydrocephalus. Postoperatively, MR demonstrated the early development of septations, the presence of subarachnoid hemorrhage, and/or the deposition of hemosiderin in four patients, findings that historically have been associated with the development of devastating clinical complications. From these data, a recommended protocol of radiologic evaluation for patients undergoing hemispherectomy has been established.     

Intratemporal vascular tumors: detection with CT and MR imaging

The diagnostic contributions of computed tomography (CT) and magnetic resonance (MR) imaging were compared in 12 patients with benign intratemporal vascular tumors (hemangioma or vascular malformation). The tumors included six in the internal acoustic canal and six in the geniculate ganglion region. Clinical and histologic correlations were made. Two of the six patients with tumors in the internal acoustic canal underwent CT, and both required gas cisternography to show the tumor. Five patients in that group underwent MR imaging, and all five studies showed the tumor. All six patients with geniculate ganglion tumors underwent CT. Results in one study were questionable, and five showed the tumor. Five patients in this group underwent MR imaging, but the MR findings were positive in only two cases. MR imaging should therefore be performed before CT in the evaluation of facial nerve dysfunction, as it demonstrated all tumors in the internal acoustic canal and some in the geniculate ganglion region. If MR findings are negative, CT should then be performed to rule out a possible geniculate ganglion lesion.