Magnetic resonance imaging of cerebral fat embolism

Summary The cerebral fat embolism is a potentially serious complication of fractures but clinical cases often go undiagnosed. Two cases of clinically diagnosed cerebral fat embolism are reported, and MR images of these patients are described. While brain CT revealed no abnormality, MR imaging showed relative low-intensity areas on T1-weighted images and high-intensity areas on T2-weighted images. In one patient follow-up MR showed nearly complete resolution of the abnormal signal. MR imaging appears to be valuable for detecting the lesions in these patients.     

Magnetic resonance imaging findings in acute pulmonary embolism

Pulmonary embolism (PE) is the third most common acute cardiovascular disease after myocardial infarction and stroke, and results in thousands of deaths each year. Improvements in MRI accuracy are ongoing with the use of parallel imaging for angiography techniques and pulmonary perfusion. This, associated with other potential advantages of MRI (e.g. a radiation free method and better safety profile of MR contrast media), reinforces its use. The aim of this paper is to perform a pictorial review of the principal findings of MRI in acute PE. Acute PE can manifest itself as complete arterial occlusion and the affected artery may be enlarged. We report the main vascular and parenchymal signs, and an overview of current literature regarding accuracy, limitations and technical aspects is provided.     

Cerebral fat embolism: diffusion-weighted magnetic resonance imaging findings

PURPOSE: To demonstrate the diffusion-weighted (DWI) magnetic resonance imaging (MRI) findings, and the follow-up MRI findings, of cerebral fat embolism in the acute stage. MATERIAL AND METHODS: The initial DWI and clinical findings of six patients with cerebral fat embolism were retrospectively evaluated. The finding of DWI with a b-value of 1000 s/mm2 (b=1000) was compared with that of DWI with a b-value of 0 s/mm2 (b=0). In three patients who underwent follow-up MRI, the interval change of the lesion on T2-weighted images was investigated. RESULTS: The characteristic DWI finding of cerebral fat embolism in the acute stage was multiple, hyperintense, dot-like lesions disseminated in the brain. These lesions were distributed dominantly in the bilateral border-zone areas. Some lesions had an ancillary location including the cortex, deep white matter, basal ganglia, and cerebellum. The lesions were more intense and numerous in DWI (b=1000) than in DWI (b=0). The findings on the follow-up T2-weighted images were multiple confluent hyperintense lesions in the white matter with progression since the initial MRI. CONCLUSION: DWI could be a sensitive tool for detecting cerebral fat embolism in the acute phase. It is recommended that DWI be included in the initial evaluation of cerebral fat embolism with MRI.     

脑性瘫痪的MRI特征

目的:探讨脑性瘫痪(脑瘫)患儿的头颅MRI表现及其与脑瘫类型的关系。方法:回顾性分析81例脑瘫患儿的临床资料与MRI表现。结果:81例脑瘫患儿MRI异常率为85.2%,痉挛型双瘫、四肢瘫、偏瘫、不随意运动型脑瘫、共济失调型脑瘫、肌张力低下型脑瘫和混合型脑瘫MRI异常率分别为92.9%、100%、100%、60%、87.5%、50%和81.8%。各类型脑瘫的MRI异常表现不同,痉挛型双瘫以脑室周围白质软化(PRL)为主,偏瘫型突出表现为单侧脑损伤,四肢瘫表现为广泛、弥漫、双侧脑损伤,不随意运动型表现为基底节病变或PVL,共济失调型绝大部分存在先天性小脑发育不全。结论:MRI有助于评价各型脑瘫的病理特点,对脑瘫病因的推测有帮助。     

MRI findings in cerebral fat embolism

The purpose of this retrospective study was to demonstrate the MRI features of cerebral manifestations in patients with fat embolism syndromes in comparison with cerebral CT (CCT). Magnetic resonance imaging was performed according to standard protocols revealing multiple small non-confluent hyperintense intracerebral lesions larger than 2 mm on proton-density and T2-weighted images to various extents in three of four patients with clinically suspected cerebral fat embolism. Cerebral CT was negative in all patients. Our findings confirm that MRI can detect cerebral fat embolism with a higher sensitivity than CCT. Thus, MRI should be the first choice for imaging of cerebral fat embolism. Received 28 November 1997; Revision received 9 March 1998; Accepted 30 March 1998     

脑脂肪栓塞的MRI及CT诊断

目的 总结脑脂肪栓塞(CFE)的临床及MRI及CT的影像特点。方法 分析3例急性CFE的临床表现、影像特点。结果 (1)3例均为长骨骨折，在外伤后或骨折固定、复位数小时后突发精神状态改变。(2)醒状昏迷是主要临床表现。(3)3例患者MRI能明确显示病灶，1例CT显示了病灶。(4)MRI、CT显示脑内病灶均呈基本对称性分布，为边缘模糊的点、片状长T1、长T2信号，CT呈低密度。病灶均累及脑干、分水岭区脑白质、基底节区、胼胝体压部。2例病灶累及小脑。(5)1例患者发病康复治疗3个月后MRI复查示脑内病灶完全消失。结论 急性脑脂肪栓塞的临床及MRI、CT影像改变具有特征性，MRI在病灶显示上优于CT。     

Magnetic resonance imaging of acute pulmonary embolism

Pulmonary embolism (PE) is a very common and potentially life-threatening disease. In comparison with CT, the clinical relevance of magnetic resonance imaging (MRI) for the assessment of PE is low. Nevertheless, as there are some potential advantages of MRI over CT (e.g. radiation free method, better safety profile of MR contrast media, capability of functional imaging). In certain patient, groups MRI might therefore be considered as a valuable alternative in the assessment of suspected PE. This article reviews the relevant MRI techniques for the evaluation of PE and gives an overview of the current literature for contrast-enhanced MR angiography of PE.     

Magnetic resonance imaging of autologous fat grafting

A 30-year-old female patient with isolated facial lipodystrophy underwent two sessions of fat injection. MR signals of injected fat at different injection ages were compared to native fat. Native T1 signal was smaller for transplant fat, probably due to a slightly lower fat content and/or fibrosis or due to higher perfusion. T2 signal of transplants was significantly higher than that of native fat. T1 post-contrast was also higher, and contrast uptake of transplanted fat increased slightly with transplant age, which could be explained by an increasing perfusion. This study demonstrates the differences and MR signal time changes of native and transplanted fat.     

Magnetic resonance imaging findings of musculoskeletal brucellosis

ObjectiveThe aim of this retrospective study was to determine the magnetic resonance imaging (MRI) findings of patients with musculoskeletal brucellosis.Materials and methodsSixty-eight among 304 patients with musculoskeletal brucellosis, aged 12–82 years (average, 50.2 years), were included in the study. Patients were diagnosed based on clinical findings, Brucella agglutination tests, and MRI findings. MRI was performed to all of the patients with sacroiliitis, spondylitis-spondylodiscitis, and peripheral arthritis.ResultsBrucella serum agglutination test was > 1/160 in all cases and blood cultures were positive in twelve cases. The most commonly affected site was the spine (57.3%), wherein lumbar vertebrae were found to be most commonly affected. The second most common affected site was sacroiliac joint (26.4%), whereas peripheral joints were affected in 11 cases (16.1%).ConclusionBrucellosis may affect various sites in musculoskeletal system. The spine was the most frequently affected site in our study. Sacroiliac joints and the other peripheral joints were less commonly involved sites. Brucellosis should be included in the differential diagnosis of a patient with arthralgia or symptoms of musculoskeletal system disorders especially in endemic areas.     

Magnetic resonance imaging findings of golf-related injuries

Injuries related to participation in golf are becoming more common given the increasing popularity of the sport itself. Golf is considered to be an activity associated with a moderate risk for sports injuries. Golf injuries are usually attributable to overuse or traumatic mechanisms and primarily occur at the elbow, wrist, shoulder, and lumbar spine. None of these injuries are unique to golf, but each of these injuries represent the most common injuries associated with golfing. This article reviews a wide range of injuries that are encountered in golfers and describes the magnetic resonance imaging findings of each of these injuries.     

Magnetic resonance imaging of intracranial atherosclerosis: Comparison of ex vivo 3T MRI and histologic findings

PurposeImaging the lipid-rich necrotic core (LRNC) is very important when evaluating the response of lipid-lowering therapy. The purpose of this study was to assess ex vivo LRNC of intracranial atherosclerosis using 3T MRI.Materials and methodsThirty-one atherosclerotic lesions from 17 specimens were analyzed (basilar artery = 15, middle cerebral artery = 16) using 3T MRI. Specimens were not chemically processed for imaging studies. Reconstructed MRI was matched with histologic sections at corresponding locations.ResultsThe median plaque thickness of intracranial atherosclerosis was 0.6 mm (0.4–2.0 mm). All specimens had a LRNC on histologic findings. Three specimens had plaque calcification on histologic findings. LRNC of 30 specimens (96.8%) appeared as homogeneous isointensity/hypointensity on T1-weighted imaging and hypointensity on T2-weighted imaging compared with T1-weighted imaging.ConclusionsAll specimens with ex vivo intracranial atherosclerosis had LRNC. Intracranial atherosclerosis could be an indication for lipid-lowering therapy, similar to previous carotid MR studies.     

Magnetic resonance imaging findings in fatal primary cerebral infection due to Chaetomium strumarium

This report describes MRI findings of a rare case of biopsy-proven fatal cerebral infection with Chaetomium strumarium in a 28-year-old man with a history of i.v. drug abuse. Magnetic resonance imaging revealed rapidly progressing lesions with irregular peripheral enhancement, possible central haemorrhage and significant mass effect. Only six cases of cerebral infection with Chaetomium have been reported in the English literature. This is the first report in the radiology literature describing the imaging findings. The previously reported cases of cerebral infection by the Chaetomium species are also reviewed.     

Magnetic resonance imaging findings in gynecologic emergencies

Gynecologic emergencies include a variety of gynecologic diseases that manifest with acute lower abdominal pain, fever, and vaginal bleeding. Recent technical advances enable the application of magnetic resonance (MR) imaging to these conditions, which may add clinically useful information in a short enough time for emergent diagnosis. In this study, the acute gynecologic conditions in which MR imaging studies were performed are reviewed, and the characteristic MR findings in gynecologic emergencies, including ovarian hemorrhage, ectopic pregnancy, tumor rupture, torsion, hemorrhage, infarction, and pelvic inflammatory diseases, are demonstrated. Familiarity of these findings aids accurate diagnosis and proper treatment choices in gynecologic emergencies.     

Magnetic resonance imaging of the cerebral aqueduct

Summary 1.5 Tesla MRI examinations were evaluated for aqueductal configuration, hydrocephalus and flow-related signal void in 70 patients with juxtaaqueductal pathology and in 20 normal controls. In the 70 cases with pathology, the aqueduct was obliterated or distorted in 34, dilated in 3, normal in 29 and not evaluable in 4. A definite flow-related signal void indicated CSF movement within the aqueduct in all normal examinations. Flow-related signal void was absent in some, but not all, patients with aqueductal obliteration and distortion. CSF turbulence can create an intra-aqueductal signal void in the dilated proximal aqueduct, despite more distal obstruction. Thus hydrocephalus related to aqueductal obstruction is frequently, but not always, associated with absence of signal void.     

Magnetic resonance imaging and histopathology of cerebral gliomas

Summary The correlation of magnetic resonance imaging (MRI) with histopathological findings was analysed in 26 patients with untreated cerebral gliomas. In low-grade gliomas, T2-weighted images demonstrated relatively homogeneous high-intensity lesions involving both the grey and the white matter. In high-grade gliomas, especially grade IV, T2-weighted images demonstrated prominent heterogeneity in signal intensity, which consisted of a hyperintense core, less hyperintense or normal intensity rim and surrounding finger-like areas of high intensity. Marked and irregular contrast enhancement was evident in all but one case of these high-grade gliomas in which gadolinium-DTPA was used. Histological examination revealed tumour cells extending as far as the borders of the high-intensity areas shown on T2-weighted images in both high-and low-grade gliomas, but in 5 of 8 low-grade and 4 of 18 high-grade gliomas, isolated tumour cells extended beyond the hyperintense areas shown on T2-weighted images.     

Magnetic resonance imaging of massive bone allografts with histologic correlation

 Objective. The objective of this study was to better understand the MRI appearance of massive bone allografts. Design. The MRI findings of three massive bone allografts imaged in vivo were correlated with the histologic findings following removal of the allografts. A fourth allograft, never implanted, was imaged and evaluated histologically. Patients. Allografts were placed for the treatment of primary or recurrent osteosarcoma. Results and conclusions. The in-vivo allografts have a heterogeneous appearance on MRI which we attribute to the revascularization process. Fibrovascular connective tissue grows into the graft in a patchy, focal fashion, down the medullary canal from the graft-host junction and adjacent to the periosteum. The marrow spaces are initially devoid of normal cellular elements and occupied by fat and gelatinous material. This normal postoperative appearance of massive bone allografts must not be interpreted as recurrent neoplasm or infection in the allograft. Recognition of these complications rests on features outside the marrow.     

Magnetic resonance imaging findings of breast juvenile papillomatosis

Juvenile papillomatosis is a rare disease affecting young women. Here we present magnetic resonance imaging features of two cases with histopathologically proven juvenile papillomatosis of the breast and review some of the relevant literature. Case 1 exhibited bilateral, well-bordered breast masses, with complex cystic and solid components. The kinetic evaluation showed continuous and plateau patterns. Case 2 featured a giant mass with a few cystic and many solid nodular components and filled the entire right breast. The kinetic evaluation showed a continuous curve.     

Magnetic resonance imaging of experimental renal hemorrhage

Experimental renal hemorrhage was induced by injecting autologous blood into the left kidney of 13 rats. To investigate the magnetic resonance (MR) characteristics of acute renal hemorrhage and subsequent stages of resolution, repetitive MR images were obtained using a 0.35 Tesla imager during a period of 21 days postinduction. A dual spin-echo imaging (TR 500 and 2,000 msec, TE 28 and 56 msec) was used to calculate the relaxation times and record the intensities in the renal medulla and cortex. Histologic examination (n = 9) indicated that blood was dispersed intrarenally, and no encapsulated hematoma developed. The signal intensity on the T1- and T2-weighted images, as well as the relaxation times in the hemorrhagic renal parenchyma were unchanged during 21 days when compared with intact kidney values. Subcapsular fresh blood had a high signal intensity on T2-weighted images. A marked overlap of the relaxation parameters between intact kidney parenchyma and diffuse intrarenal hemorrhage was observed. Detection of dispersed intrarenal blood using spin echo MR imaging may be difficult.     

Magnetic resonance imaging findings of vulvar epithelioid sarcoma

We describe here a case of vulvar epithelioid sarcoma. Epithelioid sarcoma is a malignant appendicular skin tumor that is rarely of vulvar origin. Magnetic resonance imaging (MRI) revealed a solid mass with an ulcer-like lesion and multilobulated contour. To our knowledge, this is the first case of vulvar epithelioid sarcoma described in the MRI literature.