Persistent enhancement after treatment for cerebral toxoplasmosis in patients with AIDS: predictive value for subsequent recurrence.

PURPOSETo determine the predictive imaging (CT and/or MR) features of brain toxoplasmosis recurrences in acquired immunodeficiency syndrome.METHODSThe imaging studies of patients with brain toxoplasmosis were retrospectively reviewed. Forty-three patients with significant decrease or disappearance of brain lesions under specific treatment on follow-up imaging examinations were included. MR examinations were performed using T2- and T1-weighted sequences, before and after intravenous administration of gadolinium-DOTA.RESULTSA recurrence occurred in 11 (26%) of 43 cases. Ten (91%) of these 11 patients with recurrence showed focal persistent enhancement after the initial treatment of toxoplasmosis abscess. One of the 11 patients with recurrence showed no persistent enhancement; 3 patients showed persistent enhancement but had no recurrence.CONCLUSIONSRecurrences of brain toxoplasmosis in our series correlated with persistent contrast enhancement. We hypothesize that demonstration of persistent areas of contrast enhancement after treatment for initial toxoplasmosis may be a valuable sign for identifying patients at risk for recurrence.     

Acquired immunodeficiency syndrome: correlation of radiologic and pathologic findings in the brain

The appearance on magnetic resonance (MR) and computed tomographic (CT) images of specific central nervous system disorders associated with acquired immunodeficiency syndrome in 12 cases was correlated with autopsy findings. There were three cases of human immunodeficiency virus (HIV) encephalopathy; three, primary lymphoma; three, toxoplasmosis; one, cryptococcosis; one, cytomegalovirus infection; and one, progressive multifocal leukoencephalopathy. MR imaging demonstrated the various cranial lesions more clearly than did CT. On the basis of MR imaging characteristics, HIV encephalopathy could be distinguished from other lesions, particularly progressive multifocal leukoencephalopathy. Basal ganglia were the most common sites of involvement in opportunistic infections and primary lymphoma. Reliable distinguishing features among lesions of the basal ganglia were not found, except for cryptococcal lesions, which had a unique appearance.     

Imaging in acute basilar artery thrombosis

The aim of this study was to review the imaging features in acute (<24 h) basilar artery thrombosis. CT and MR studies in 11 patients with clinical diagnosis of acute basilar artery thrombosis were retrospectively reviewed. MR angiography was obtained in 4 patients. Correlation with clinical symptoms was performed. Multiple cranial nerve palsies and hemiparesis were the most common clincal symptoms at presentation. CT revealed hyperdense basilar arteries (n=7) and hypodensities in the posterior circulation territory (n=8). In one instance, the infarction was hemorrhagic. MR imaging showed absence of flow void within the basilar in 6 patients and MRA (using both PC and TOF techniques) confirmed absence of blood flow in 4 basilar arteries. One week after presentation, 5 patients died. Autopsy was obtained in 1 case and confirmed the diagnosis of basilar artery thrombosis. Basilar artery thrombosis has fairly typical imaging features by both CT and MR. MRA may be used to confirm the diagnosis. Prompt recognition may lead to early thrombolytic treatment and may improve survival.     

MR imaging of brain stem gliomas

Magnetic resonance (MR) and CT examinations of 26 patients with the established or clinically suspected diagnosis of brain stem glioma were reviewed. Eleven tumors were seen on both MR and CT. The entire extent of the abnormality was better outlined on MR, although CT was more advantageous in demonstrating cystic components and calcium deposition. Magnetic resonance and CT depicted focal intratumoral hemorrhage equally. Magnetic resonance was found to be particularly suitable to follow up the progression or regression of the disease. Of particular interest were two patients with evidence of aqueductal obstruction but normal CT appearance of the midbrain; the causative abnormality, believed to be a glioma, was clearly shown by MR imaging. In nine patients the normal appearance was helpful to exclude the possibility of a brain stem glioma. Thus far, results have shown 100% sensitivity (true positive ratio) and specificity (true negative ratio) with MR in the evaluation of brain stem gliomas. It is concluded that MR imaging should be the examination of choice and could be the definitive screening procedure in patients with suspected brain stem glioma.     

CT and MR imaging of craniopharyngioma

We reviewed imaging findings of CT and MR imaging in 20 cases of surgically confirmed craniopharyngioma in an attempt to determine their relation to patterns of tumor extent. The relationship between these patterns and the frequency of preoperative CT diagnosis and MR imaging diagnosis according to the surgical diagnosis were determined. The CT technique was superior to MR imaging in the detection of calcification. The MR imaging technique was superior to CT for determining tumor extent and provided valuable information about the relationships of the tumor to surrounding structures. Thus, CT and MR imaging have complementary roles in the diagnosis of craniopharyngiomas. In cases of possible craniopharyngioma, noncontrast sagittal T1-weighted images may enable the identification of the normal pituitary, possibly leading to the correct diagnosis. Received 6 November 1995; Revision received 9 August 1996; Accepted 14 October 1996     

Brain ischemia: CT and MRI techniques in acute ischemic stroke

Imaging plays a central role for intravenous and intra-arterial arterial ischemic stroke treatment patient selection.Computed tomography (CT) / CT angiography or magnetic resonance (MR) / MR angiography imaging are used to exclude stroke mimics and haemorrhage, to determine the cause and mechanism of stroke, to define the extension of brain infarct and to identify the arterial occlusion. Imaging may identify the patients that will be benefit more from revascularization therapies independently of the conventional therapeutic time window allowing individualized treatment decisions and improving individual patient outcome. Multiparametric CT/MR imaging may be used to identify the extension of potential viable brain tissue (penumbra) and of irreversible brain lesion (core) using CT perfusion and/or diffusion weighed and perfusion weighted MR imaging. The status of the arterial collateral circulation and the type and extension of the clot may be assessed by imaging.The accuracy and the clinical significance for treatment and patient clinical outcome of different imaging techniques are reviewed.     

Paraorbital tumors and tumor-like conditions: role of CT and MRI

Tumors and tumor-like conditions of the paraorbital tissues that affect the eye usually require CT or MR imaging for complete evaluation. This article provides an overview of the wide variety of pathologic conditions to be considered when a paraorbital tumor is discovered or suspected. Some of the CT and MR imaging features of these disorders that aid in the differential diagnosis are reviewed.     

脑多发胶质瘤影像与病理对照研究

目的 探讨脑多发胶质瘤的影像特点与其病理结果的关系,提高对本病的认识及诊断水平.资料与方法 分析6例经手术病理证实的脑多发胶质瘤的MR及CT影像学资料、病理结果.结果 6例共计13个病灶,MR及CT影像表现为脑内各叶多发肿块样病灶,以额叶最多见,病灶间相互独立.5例影像增强共显示11个病灶,其中7个病灶呈中度至明显强化,病理结果为胶质瘤Ⅲ～Ⅳ级;4个病灶无明显强化,其中2个病灶病理结果为胶质瘤Ⅱ级.结论 脑多发胶质瘤影像表现特征与其病理学类型及分级相关,可初步作出诊断并判断其恶性程度,对临床治疗提供更多帮助.     

Cerebral amyloid angiopathy-related inflammation: imaging findings and clinical outcome

Introduction

We aim to investigate the clinical onset, computed tomography (CT) and magnetic resonance (MR) imaging findings, and follow-up of patients with cerebral amyloid angiopathy (CAA)-related inflammation, an uncommon but clinically striking presentation of CAA.

Methods

We retrospectively reviewed the clinical manifestations, CT/MR imaging findings, and outcome of ten consecutive patients with CAA-related inflammation. In each patient, a brain CT study was performed at hospital admission, and brain MR imaging was carried out 2 to 4 days later. Clinical and radiologic follow-up findings were evaluated in all patients.

Results

The most common clinical onset was rapidly progressive cognitive decline, followed by focal neurological signs. Brain CT/MR showed unenhanced expansive subcortical lesions, corresponding to areas of vasogenic edema, associated with chronic lobar, cortical, or cortical–subcortical micro/macrohemorrhages. Clinical symptoms recovered in a few weeks under treatment in eight patients and spontaneously in the remaining two. MRI follow-up at 2 to 12 months after treatment showed resolution of the lesions. Three patients experienced symptomatic disease recurrence, with new lesions on CT/MR.

Conclusion

In the absence of histological data, early recognition of the clinical symptoms and typical radiologic features of CAA-related inflammation is essential to enable timely establishment of proper treatment.     

Leukodystrophy in children: a pictorial review of MR imaging features.

Dysmyelinating diseases, or leukodystrophies, encompass a wide spectrum of inherited neurodegenerative disorders affecting the integrity of myelin in the brain and peripheral nerves. Most of these disorders fall into one of three categories-lysosomal storage diseases, peroxisomal disorders, and diseases caused by mitochondrial dysfunction-and each leukodystrophy has distinctive clinical, biochemical, pathologic, and radiologic features. Magnetic resonance (MR) imaging has become the primary imaging modality in patients with leukodystrophy and plays an important role in the identification, localization, and characterization of underlying white matter abnormalities in affected patients. MR imaging has also been extensively used to monitor the natural progression of various white matter disorders and the response to therapy. Although the MR imaging features of leukodystrophy are often nonspecific, systematic analysis of the finer details of disease involvement may permit a narrower differential diagnosis, which the clinician can then further refine with knowledge of patient history, clinical testing, and metabolic analysis.     

Diagnosis of Sturge-Weber syndrome: comparison of the efficacy of CT and MR imaging in 14 cases.

Sturge-Weber syndrome is a neurocutaneous syndrome that includes facial and leptomeningeal angiomas. Imaging findings include cerebral lobar atrophy, brain calcifications, choroid plexus enlargement, cranial diplo? prominence, and venous abnormalities. We compared the efficacy of CT and MR imaging in making the diagnosis in 14 consecutive patients. CT, with and without contrast enhancement, was performed in all patients, and 11 of the 14 had MR imaging (eight before and after administration of IV gadopentetate dimeglumine). MR imaging was better than CT in showing the extent and degree of brain parenchymal atrophy, the presumed ischemic changes affecting the gray and white matter, and the cranial diploetic prominence on the affected side. MR imaging after contrast administration permitted a better evaluation of the extent and patency of the leptomeningeal angiomatous malformation and the parenchymal venous anomalies. CT was better than MR imaging in showing the presence and extent of cortical calcifications. Enhanced CT and MR imaging were equal in evaluating the prominence of the ipsilateral choroid plexus. Our experience indicates that contrast-enhanced MR imaging is the method of choice in the diagnosis of Sturge-Weber syndrome. Unenhanced CT should be used only if MR findings are normal, to exclude the presence of intracranial calcifications.     

Vertex epidural hematomas: imaging findings and diagnostic pitfalls

PURPOSE: Our purpose was to show the computed tomography (CT) and magnetic resonance (MR) imaging features of vertex epidural hematomas (EDHs) and emphasize pitfalls in the diagnosis of this entity. SUBJECTS AND METHODS: The neuroradiologic studies of four patients (CT in four, MR imaging and MR venography in one) were evaluated for EDH shape, size and appearance. RESULTS: EDHs were biconvex in three patients and crescentic in one patient. CT appearances included a collection that was hyperdense (two patients), generally isodense with a few regions of hyperdensity (one patient) and mixed hyperdense and hypodense (one patient). MR imaging findings in one patient consisted of hyperintense signal on T1-weighted images and hypointense signal on T2-weighted images. Inferior displacement of the superior sagittal sinus was seen in two patients. Diagnosis of a small vertex EDH was difficult on routine axial CT in one patient, but apparent on MR imaging and MR venography. CONCLUSIONS: Small vertex EDHs can be difficult to diagnose on routine CT. MR imaging or thin section CT should be performed to exclude the diagnosis in patients with trauma to the skull vertex.     

Imaging features of aggressive angiomyxoma

AIM: To describe the imaging features of aggressive angiomyxoma in a rare benign mesenchymal tumour most frequently arising from the perineum in young female patients. MATERIALS AND METHODS: We reviewed the computed tomography (CT) and magnetic resonance (MR) imaging features of patients with aggressive angiomyxoma who were referred to our hospital. The imaging features were correlated with clinical information and pathology in all patients. RESULTS: Four CT and five MR studies were available for five patients (all women, mean age 39, range 24-55). Three patients had recurrent tumour at follow-up. CT and MR imaging demonstrated a well-defined mass-displacing adjacent structures. The tumour was of low attenuation relative to muscle on CT. On MR, the tumour was isointense relative to muscle on T1-weighted image, hyperintense on T2-weighted image and enhanced avidly after gadolinium contrast with a characteristic "swirled" internal pattern. MR imaging demonstrates the extent of the tumour and its relation to the pelvic floor. Recurrent tumour has a similar appearance to the primary lesion. CONCLUSION: The MR appearances of aggressive angiomyxomas are characteristic, and the diagnosis should be considered in any young woman presenting with a well-defined mass arising from the perineum.     

Imaging changes and cognitive outcome in primary CNS lymphoma after enhanced chemotherapy delivery

BACKGROUND AND PURPOSE: In children, MR imaging abnormalities consistent with leukoencephalopathy after treatment for hematologic malignancy do not correlate with neurologic dysfunction and are often overinterpreted with regard to clinical significance. We hypothesized that this would also be true in primary CNS lymphoma (PCNSL) patients who attained a complete response (CR) after treatment with chemotherapy and osmotic blood-brain barrier disruption (BBBD). We hypothesized that cognitive function loss measured after tissue diagnosis but before BBBD-enhanced chemotherapy could be correlated with brain changes visualized by imaging, whereas a correlation would not be present after therapy if the patient attained a complete tumor response, analogous to the findings in children. METHODS: Sixteen primary CNS lymphoma patients were followed after CR (no enhancing tumor) by using a methotrexate-based regimen. Neuropsychological (NP) cognitive testing and MR imaging or CT (when MR imaging was not available) were performed before treatment and at completion of the 12-month treatment for each patient. Thereafter, the same studies were available for nine of these 16 CR patients, who were followed for a median of 55 months. Zone I was defined as enhancing tumor, and zone II as surrounding abnormal MR T2 signal intensity or low-attenuation CT. The cognitive scores were converted to Z scores and the MR T2 signal intensity or CT low-attenuated changes were converted to a summary zone II abnormality score. RESULTS: A significant association between neurocognitive data and zone II abnormality was found at baseline after tissue diagnosis but before chemotherapy (r = -.55; P < .028), but no correlation existed at end of treatment. Imaging studies showed that seven patients developed a new T2 or low-attenuation abnormality by the end of treatment, whereas 15 patients showed a decrease, stable appearance, or complete resolution of their baseline zone II abnormality by end of treatment. Although cognitive loss compared with age-matched control subjects was common before starting therapy, by the end of treatment all patients' cognitive function improved significantly (P < .005). CONCLUSION: The current data suggest that neither enhanced chemotherapy delivery nor changes in MR imaging T2 signal intensity or CT low attenuation, in PCNSL patients who attained a CR, were associated with a decrease in cognitive function.     

Multiple glioblastomas: CT and MR features

The aim of this study was to analyze the CT and MR features of multiple glioblastomas, and to determine the best imaging modality for the initial diagnosis. The CT (four exams) and MR imaging (eight exams) of eight patients with proven multiple glioblastomas were reviewed by two neuroradiologists. The lesions were always hypo- or isodense on CT and hyperintense on T2-weighted images (100 %). They were usually hypo- or isointense on T1-weighted images (90 %). Edema and mass effect were very variable. After contrast media administration, the enhancement was mostly strong (71 % on CT and 70 % on MR), often either heterogeneous or ring-like. The different lesions of a patient often had a different pattern on MR (75 % of cases). Meningeal or ventricular enhancement, suggestive of a possible way of dissemination, was rare. In case of multiple cerebral masses, multiple glioblastomas should be considered as a possible diagnosis in addition to the better known diagnosis of brain metastases, abscesses, or multifocal lymphomas. Moderate edema and mass effect on MR associated with strong and heterogeneous enhancement are suggestive of feature of multiple glioblastomas. Magnetic resonance allows rarely the visualization of a dissemination route. Received: 10 March 2000 Revised: 18 May 2000 Accepted: 22 May 2000     

颅内原发恶性淋巴瘤的MRI诊断(附12例报告)

目的　探讨颅内原发恶性淋巴瘤CT及MR的表现特征 ,以提高诊断准确率。方法　对 12例经手术病理证实的颅内原发恶性淋巴瘤的CT及MR表现进行回顾分析。结果　共检出 3 2个病灶 ,其中单发 9例 ,分别位于额、颞、顶叶深部脑白质 8例 ,位于颞叶表面 1例 ;多发 3例 ,病灶多位于深部脑白质。CT多表现为圆形或类圆形稍高密度灶 ,MRI表现为T1WI低或等信号 ,T2 WI为稍低信号。多数病灶周围有轻 -中度高信号水肿带 ,病灶边界尚清楚。增强扫描见所有病灶均有强化 ,2 3个 ( 72 .0 % )病灶呈均匀强化 ,18个 ( 5 6.2 5 % )病灶强化后出现缺口或凹陷改变。病理结果 :11例为非何杰金氏淋巴瘤 ,1例为浆细胞淋巴瘤。结论　尽管颅内原发恶性淋巴瘤的影像表现与其它颅内肿瘤如脑膜瘤、胶质瘤及转移瘤等有许多相似之处 ,但通过认真分析其影像特征 ,术前的正确诊断是有可能的     

CT and MRI diagnosis of silent sinus syndrome

Purpose

The purpose of this study was to determine computed tomography (CT) and magnetic resonance (MR) findings of silent sinus syndrome (SSS) — a rare clinical entity with the constellation of progressive enophthalmos and hypoglobus, facial asymmetry and possible diplopia — due to otherwise asymptomatic maxillary sinus disease.

Materials and methods

We reviewed the pre- and postoperative CT and MR images of six patients with a definitive diagnosis of SSS and compared the radiological and clinical findings with those reported in the literature.

Results

The CT and MR studies demonstrated in all cases the most characteristic imaging features of SSS reported in the literature.

Conclusions

Both CT and MR imaging enable a diagnosis of SSS to be made, but CT provides a better depiction of all features of SSS necessary for diagnosis and differentiation from other sinus conditions, even in patients without a clinical suspicion of SSS.     

Advances in imaging of lymph flow disorders.

Conventional oil-contrast lymphography has long been the mainstay for lymphatic imaging. However, the emergence of computed tomography (CT) and magnetic resonance (MR) imaging has severely curtailed its use. Because of recent improvements and refinements, lymphangioscintigraphy now permits high-resolution imaging of peripheral lymphatic vessels and provides insight into lymph flow dynamics. It is indispensable for patients with known or suspected lymphatic circulatory disorders in confirming the diagnosis and delineating the pathogenesis and evolution of lymphedema. In addition, lymphangioscintigraphy helps evaluate lymphatic truncal anatomy and radiotracer transport. It can also be used to evaluate the efficacy of various treatment options designed to facilitate lymph flow or reduce lymph formation. The procedure is essentially noninvasive, can easily be repeated, and does not adversely affect the lymphatic vascular endothelium. MR imaging complements lymphangioscintigraphy in the monitoring and treatment of more complex lymphatic circulatory disorders, whereas CT facilitates catheter-guided percutaneous sclerosis or obliteration of specific lymphangiectasia or lymphangioma syndromes. Ultrasonography has proved useful in the setting of filariasis. Patients with a provisional diagnosis of peripheral lymphatic dysfunction or idiopathic edema should undergo diagnostic lymphangioscintigraphy and, in some cases, MR imaging to verify diagnostic accuracy, pinpoint the specific abnormality, and help guide subsequent therapy.     

艾滋病并发卡氏肺孢子虫肺炎的X线和CT诊断

目的 :探讨艾滋病 (AIDS)并发卡氏肺孢子虫肺炎 (PCP)的胸部X线和CT表现。材料和方法 :对 6例经证实的艾滋病并发卡氏肺孢子虫肺炎患者的胸部X线照片 ( 6例 )和CT扫描 ( 2例 )进行回顾性分析。结果 :典型表现为双侧肺门周围以及中、下肺野弥漫性网状阴影 ,部分渗出性病变可以相互融合 ,呈斑片样或磨玻璃样改变。少见表现有肺囊性改变、肺实变、肺门淋巴结增大、胸腔积液及气胸等。结论 :艾滋病并发卡氏肺孢子虫肺炎的特异性诊断是找到病原体 ,但是HIV抗体检测阳性者出现典型胸部影像表现结合临床症状 ,并排除其他免疫低下所致的细菌性感染或肿瘤 ,复方新诺明治疗有效 ,诊断AIDS并PCP可以成立。     

CT and MR characteristics of cerebral sparganosis

BACKGROUND AND PURPOSE: Sparganosis is a rare parasitic infection in humans by a larval cestode of the genus Spirometra. Preoperative diagnosis of cerebral sparganosis in the past has been very difficult. Our objective was to evaluate the CT and MR features of cerebral sparganosis in order to make a definite diagnosis. MATERIALS AND METHODS: We retrospectively reviewed 25 patients (13 male and 12 female; age range, 9-83 years) who proved to have cerebral sparganosis. Fifteen patients underwent MR imaging: 2 patients had CT scanning, and the remaining 8 had both CT and MR scanning. We focused on evaluating the imaging features on CT and MR. RESULTS: All patients showed edema and degeneration of cerebral white matter. All but 1 had a unilateral lesion. Twenty-two patients had ipsilateral ventricular dilation. The new finding was a tunnel sign, approximately 4 cm in length and 0.8 cm in width, column or fusiform shaped on postcontrast coronal and sagittal MR images (n = 10). Thirteen patients showed bead-like enhancement, but solitary ring enhancement was common on the CT images (n = 2). The wall of the ring and tunnel appeared isointense or slightly hyperintense on T2-weighted images. Punctate calcifications were seen in 6 patients on CT images but only in 3 patients on the MR images. Hemorrhage was seen in 4 patients on the MR images. An intact whitish, stringlike, living worm was found (n = 5). CONCLUSION: The most characteristic finding was a tunnel sign on postcontrast MR images. The most common finding was bead-shaped enhancement. MR is superior to CT in demonstrating the extent and number of lesions, except punctate calcifications. Combined with clinical data and enzyme-linked immunosorbent assay, the preoperative diagnosis of cerebral sparganosis could be established on MR imaging.