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 features of asymptomatic bipartite patella

Objective

The purpose of our study was to describe the magnetic resonance imaging (MRI) features of bipartite patella in asymptomatic patients.

Materials and methods

The study was prospective in type and performed following institutional ethical committees approval. In total, 25 subjects were recruited into the study and informed consent obtained in each case. The local radiology database was utilised in conjunction with a clinical questionnaire to identify patients who had asymptomatic bipartite patella. Any patient with a history of trauma or symptomatic disease was excluded from the study. MRI imaging was performed in each case on a 1.5 T system using a dedicated knee coil and a standardised knee protocol. The images obtained were then analysed by two musculoskeletal radiologists in consensus.

Results

Of the 25 subjects, there were 8 females and 17 males. The mean age was 34.6 years. All but one of the bipartite fragments were located on the superolateral aspect of the patella. In 23 cases, one fragment was identified. The average transverse diameter of the fragment was 12.8 mm. The average distance between the fragment and the adjacent patella in the axial plane was 1.46 mm. In addition, the cartilage overlying the patella and accessory fragment was intact in all cases. The average thickness of the patella cartilage at its border to the fragment was 2.4 mm with an average ratio of the cartilage thickness of the fragment as compared with the cartilage thickness of the patella of 0.72. There was no evidence of high signal or bone marrow oedema on fluid sensitive sequences within either the patella or the fragment in any of the patients. Fluid was identified in the cleft between the patella and the fragment in the majority of cases.

Conclusions

Asymptomatic bipartite patella is characterised by intact but thinned cartilage along the border between the patella and the fragment, fluid between the cleft and a lack of any bone marrow oedema or high signal within the patella or its fragment.     

肝脏血管平滑肌脂肪瘤MRI表现

目的：总结分析肝脏血管平滑肌脂肪瘤（AML）的MRI表现,比较上皮样与非上皮样肝脏AML的MRI表现差异。方法：搜集经手术病理证实的肝脏AML患者15例,1l例行MRI检查,其中上皮样AML5例,非上皮样AML6例,1例非上皮样AML仅行MRI平扫,其余10例均行MRI平扫及动态增强扫描。结果：化学位移成像栓出7例肿瘤的脂肪成分,而频率饱和法仅检出3例肿瘤的脂肪成像。无脂肪型中上皮样与非上皮样AML各2例;少脂肪型中上皮样AML1例,非上皮样AML3例;富脂肪型中上皮样AML2例,非上皮样AML1例;上皮样与非上皮样AML脂肪含量相仿。10例行增强扫描的病例中动脉期强化9例,门脉期强化6例,延迟期强化5例,延迟期环形包膜样强化9例,动态增强曲线8例呈动脉期速升,门脉期及延迟期强化迅速减低。结论：上皮样与非上皮样AML影像学表现差异较小,MRI检出脂肪含量多寡难以作为肿瘤是否为上皮样AML的诊断标准。在MRI动态增强扫描中,上皮样AML与富血管平滑肌的经典型AML强化形式相似。     

Magnetic resonance imaging of pyomyositis

Pyomyositis is a relatively rare entity in temperate climates. Because of its rarity and its nonspecific clinical and radiographic findings, pyomyositis may be misdiagnosed and may cause severe morbidity and mortality. We present magnetic resonance imaging findings in two cases of pyomyositis. Magnetic resonance imaging was helpful in differentiating other pathological processes from pyomyositis, outlining the extent of involvement, and localizing the fluid collection.     

Magnetic resonance imaging features of papillary breast lesions

PurposeThis study was aimed to assess the role of magnetic resonance imaging (MRI) in the evaluation of the papillary lesions of the breast and their morphological relationship with the mammary ducts. The potential diagnostic contributory role of ductal oriented protocols to conventional dynamic magnetic resonance examination was also explored.Materials and methodsRetrospective data were collected from 46 patients who had been diagnosed with papillary breast lesions and undergone magnetic resonance examination.The presence of dilated ducts and their morphological relation with the lesion were recorded. Lesions were classified as follows: papilloma, papillomatosis and malignant papillary lesion. Statistical difference between groups was studied for each morphological and dynamic lesion characteristic.ResultsDilated ducts and characteristics of intraductal material can be identified by magnetic resonance imaging. Certain MRI findings such as a mass with crescentic peripheral fluid or focal intraductal mass on T2 weighted images may suggest the presence of an intraductal/papillary lesion. In this respect, non-fatsat T2 weighted images appear particularly useful. There was a significant difference between papilloma and papillomatosis with regard to segmental and heterogeneous contrast enhancement (p < 0.05 for both comparisons). In addition, there was a significant difference between papillomas and carcinomas with regard to homogenous, heterogeneous and segmental contrast enhancement (p < 0.05 for all). On the other hand, papillomatosis and carcinoma did not differ significantly in terms of any of the morphological or dynamical MR criteria compared.ConclusionPapillary lesions can be detected by MRI. Despite some overlaps in MRI findings between carcinoma, papilloma and papillomatosis, MRI may help differentiate these lesions. Major benefit of retroareolar imaging appears to arise from its ability to demonstrate ductal relation and extension of contrast enhanced regions.     

关节软骨MR成像进展

随着软骨序列的开发和应用，MRI对关节软骨的评价越来越重要。本文就关节软骨的MRI表现、关节软骨的MRI序列和扫描技术、关节软骨损伤以及修复术后MRI评价等方面进行了综述。     

烟雾病的MRI、MRA诊断价值

 目的探讨MRI、MRA对烟雾病(Moyamoya病)的诊断价值.方法对11例Moyamoya病患者行MRI和MRA检查,MRI包括横轴位和矢状位T1WI、T2WI、FLAIR;MRA采用3D TOF法,3例行增强MRA.结果MRI表现为:(1)Moyamoya血管:双侧3例,单侧8例;(2)脑梗死和脑软化灶11例;(3)局部脑萎缩3例.MRA表现为3例双侧颈内动脉狭窄,双侧大脑中、前动脉闭塞,大脑后动脉形成异常血管网;6例右侧颈内动脉、大脑中动脉狭窄;2例左侧颈内动脉、大脑中动脉狭窄.结论MRI能良好的显示脑内病变,MRA能较完整的显示异常血管,MRI与MRA相结合可作为烟雾病诊断的首选检查方法.     

Magnetic resonance imaging in glenohumeral instability

The glenohumeral joint is the most commonly dislocated joint of the body and anterior instability is the most common type of shoulder instability.Magnetic resonance (MR) imaging,and more recently,MR arthrography,have become the essential investigation modalities of glenohumeral instability,especially for pre-procedure evaluation before arthroscopic surgery.Injuries associated with glenohumeral instability are variable,and can involve the bones,the labor-ligamentous components,or the rotator cuff.Anterior instability is associated with injuries of the anterior labrum and the anterior band of the inferior glenohumeral ligament,in the form of Bankart lesion and its variants;whereas posterior instability is associated with reverse Bankart and reverse Hill-Sachs lesion.Multidirectional instability often has no labral pathology on imaging but shows specific osseous changes such as increased chondrolabral retroversion.This article reviews the relevant anatomy in brief,the MR imaging technique and the arthrographic technique,and describes the MR findings in each type of instability as well as common imaging pitfalls.     

胎儿肾脏积水的MR影像及预后评估

目的利用1．5T高场强扫描机,对胎儿肾脏积水的MR影像及预后进行评估。方法利用B超筛查发现胎儿肾脏积水并进行MR进一步检查的病例34例,胎龄24～37周。结果在34例胎儿中,MR诊断单侧重复肾伴上半肾积水3例（1例产后MR证实,2例引产）,盆腔内囊性病灶致双侧肾脏积水2例（1例产后证实为盆腔巨大畸胎瘤致双肾积水,1例失访）,脑室扩张且单侧肾脏积水2例（1例引产,1例失访）,双侧’肾脏及输尿管扩张积水且肺发育不良1例（产后MR证实,放弃治疗）,双侧肾脏积水伴脐膨出1例（产后证实为脐肠瘘并行手术治疗,双侧肾脏积水随访改善）,双侧肾脏积水伴左肾周积液1例（引产）,单纯性肾脏积水24例（产后确诊左侧UPJ进行手术3例,左侧肾脏积水随访中2例,6例左侧、2例右侧及5例双侧肾脏积水产后超声随访正常,失访6例）;产后确诊UPJ的3例胎儿肾脏皮质厚度平均2mm,随访正常的13例胎儿肾脏皮质厚度平均3．5mm。结论MR影像能够对胎儿肾脏积水的病因进一步评估,有利于胎儿肾脏积水的预后判断。     

Magnetic resonance imaging of musculoaponeurotic fibromatosis

Musculoaponeurotic fibromatosis can be mistaken for soft-tissue sarcoma both clinically and on X-ray computed tomography. Magnetic resonance imaging (MRI) in three patients with this condition enabled the correct diagnosis to be made prospectively in two. The appearance on MRI of a heterogeneous mass with well-defined, predominantly peripheral areas of very low signal intensity due to dense fibrous tissue and areas of medium to high signal intensity corresponding to a more cellular stroma should raise the the suspicion of musculoaponeurotic fibromatosis. Cellular areas within the tumour showed moderate enhancement after gadolinium diethylene triamine pentaacetic acid administration.     

Magnetic resonance imaging of limbic encephalitis

Summary In two patients with limbic encephalitis serial magnetic resonance (MR) imaging showed evolution of abnormal high-signal intensity in both hippocampal formations on T2-weighted images.     

大动脉炎血管壁的磁共振表现特点

目的：分析大动脉炎血管壁的MR表现特征及其临床应用价值。方法：32例临床确诊为大动脉炎的患者接受了MR检查,其中处于病情活动期20例,非活动期12例。分析并比较了两组患者受累动脉管壁的MR表现特征。结果：所有受累动脉的血管壁均不同程度的环形增厚。活动期组患者的管壁厚度较非活动期组患者明显增厚[（4．6±0．4）mm vs（3．4±0．6）mm,P〈0．01];比较两组增厚的血管壁形态,管壁呈“多环征”（分别为89／100和25／60）、内层明显强化（分别为66／100和24／60）、血管外界模糊不清（分别为72／100和20／60）等征象,经Х^2检验差异均有统计学意义（P〈0．01）。结论：大动脉炎血管壁的MR主要征象是管壁增厚及其信号改变。MRI能观察血管壁精细的形态学变化,对大动脉炎管腔狭窄前的早期诊断以及活动性判断具有重要价值。     

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 features of chloroma of the shoulder

 A patient with a history of essential thrombocytosis presented with diffuse skeletal pain and restricted motion of the left shoulder. Magnetic resonance imaging (MRI) of the left glenohumeral joint showed a soft tissue mass that displaced the rotator cuff. Biopsy of the mass revealed chloroma. MRI is the method that best characterizes this lesion.     

Peritumoral edema in osteoid osteoma on magnetic resonance imaging

Objective.To determine whether there is a relationship between the peritumoral edema caused by osteoid osteoma seen on magnetic resonance (MR) imaging and the patient’s age, duration of symptoms, or location of the lesion. Design and patients. All histologically proven osteoid osteomas seen in our institutions during a 5-year period in patients with known age, gender, duration of symptoms, and available radiological and MR imaging examinations were included in this study. The extent of the edema in the bone marrow and extraosseous soft tissue around the nidus of osteoid osteoma on T2-weighted MR imaging were graded from 1 (nonexistent) to 4 (extensive) by two masked observers. The relationships between the patient’s age, duration of symptoms, and location of lesions were evaluated by Pearson’s correlation coefficient and analysis of variance. Results.Twenty-seven cases met the inclusion criteria. The observer agreement on grading was good. Patients of 15 years of age or younger had significantly higher grades than patients older than 15 years. There was a moderate negative linear correlation between the patient’s age and peritumoral edema. No significant relationship was identified between edema and the duration of symptoms or the location of lesions. Conclusion. Osteoid osteomas in younger patients tend to be associated with more extensive peritumoral edema. Received: 13 March 1998 Revision requested: 3 August 1998 Revision received: 12 January 1999 Accepted: 2 March 1999     

应激性心肌病的磁共振成像特点

目的 分析总结应激性心肌病的磁共振成像特点.方法 对确诊的6例应激性心肌病患者行心脏磁共振成像检查,对其磁共振成像特点进行分析总结.结果 所有患者左室射血分数降低（23％ ～45％,平均35％）,心室发生气球样变形（4例位于心尖,2例位于心室中部）;但受累节段无明显的坏死和纤维化,这与急性心肌梗死的磁共振成像特点不同.结论 应激性心肌病患者有典型的磁共振成像特点,有助于与急性心肌梗死的鉴别.     

输卵管积液的MRI研究

目的：分析输卵管积液的磁共振成像（MRI）表现,提高 MRI 诊断的准确性。方法：回顾性研究经手术和病理证实的41例共56个输卵管积液病灶的 MRI 表现,分析病灶的部位、大小、形态、信号、管壁厚度、增强表现及积液 ADC值。结果：56个输卵管积液病灶中单纯性输卵管积液37个,输卵管积脓14个,输卵管积血5个。可见3种 MRI 形态学类型：Ⅰ型病灶18个（32％）,输卵管积液呈管状;Ⅱ型病灶29个（52％）,呈囊状合并管状结构;Ⅲ型病灶9个（16％）,呈囊状,无管状结构。14个输卵管积脓病灶的平均壁厚0．37 cm,注射对比剂后管壁显著强化;其余42个病灶平均壁厚0．17 cm,管壁轻度强化。当管壁厚度以0．25 cm 为界值时,诊断输卵管积脓的敏感度、特异度和准确率分别为72％、95％和83％。单纯积液病灶的平均 ADC 值为3．0×10－3 mm2／s,明显高于积脓的1．4×10－3 mm2／s 及积血的1．9×10－3 mm2／s。术前 MRI 误诊11个（20％）。结论：MRI 能较好的显示输卵管积液的形态特征,绝大多数输卵管积液病灶有典型表现,部分无管状结构的囊性病灶极易误诊。     

Magnetic resonance imaging of pilomatricoma

Two patients (a 16-month-old boy and a 53-year-old man) were referred for MR imaging of a small, subcutaneous nodule at the forearm. Plain films were available in one patient and showed a non-specific well-circumscribed lesion. Upon ultrasonography (1 patient), a nodular, well-circumscribed, hyperechoic lesion was seen. In both cases spin-echo (SE) T1-weighted images (T1W1) showed homogeneous, intermediate signal intensity (SI). On gadolinium-enhanced T1W1 (1 patient), no enhancement was observed. Both lesions showed predominant low-to-intermediate SI on T2WI. At histological examination characteristic findings of pilomatricoma were observed.     

Diffusion-weighted magnetic resonance imaging for demonstration of cerebral infarcts

Summary Forty-one patients demonstrating clinical symptoms for cerebral infarction were investigated by magnetic resonance imaging with diffusion-weighted echo-planar imaging (DWI) and T2-weighted imaging (T2WI). In 8 patients only DWI showed the cerebral lesions clearly. One patient with positive DWI and T2WI suffered from HSV encephalitis. DWI is superior to T2WI in assessment of small cortical infarcts and cerebral infarction in patients with preexisting vascular lesions. DWI is not specific, so other causes like cerebral hematoma and encephalitis have to be considered.      

Longitudinal stress fractures of the tibia: diagnosis by magnetic resonance imaging

 Objective. Previous works describe magnetic resonance (MR) imaging characteristics of stress fractures. Diagnosis of the atypical, longitudinal type of stress fracture has been reported using computed tomography (CT). This report focuses on MR imaging of longitudinal stress fractures of the tibia. Materials and methods. Six cases are presented in which a longitudinal linear abnormal marrow signal was detected in the middle and distal parts of the tibial shaft. Five patients were imaged using a 1.5 Tesla MR unit. Axial, sagittal and coronal T1 and T2-weighted or fat suppressed proton density fast spin echo images were obtained in all but one patient. One patient was imaged using a 0.5 Tesla MR unit with axial and coronal T1- and T2-weighted sequences. Initial conventional radiographs seen at clinical presentation were interpreted as normal in all cases. Two patients underwent radionuclide bone scan, and one patient was imaged with CT prior to MR imaging. Results. In each instance, MR imaging demonstrated linear marrow signal abnormalities orientated along the long axis of the tibial shaft. Endosteal and periosteal callus was identified on axial images. In all cases, MR imaging clearly demonstrated a fracture extending through one cortex with abnormal signal in both the marrow cavity as well as adjacent soft tissues indicating edema. Conclusion. MR imaging was shown to be excellent for demonstration of fracture lines, callus, and marrow and soft tissue abnormalities seen in association with longitudinal stress fractures.