Basal ganglia hyperintensity on T1-weighted MRI in Rendu-Osler-Weber disease

The purpose of this study was to evaluate possible central nervous system (CNS) involvement in Rendu-Osler-Weber (ROW) disease in magnetic resonance imaging (MRI). Three patients with symptomatic ROW disease underwent brain MRI. Brain MRI depicted in all three of them increased signal intensity on T1-weighted images involving the globus pallidus and cerebral crura bilaterally. Laboratory studies of the two men showed iron deficiency anemia, while all three of them had normal liver function tests and increased manganese blood concentration. Gastroscopy and colonoscopy revealed a gastric and a cecal arteriovenous malformation (AVM) in the first one, while pulmonary and hepatic computed tomography (CT) angiography did not detect any intrahepatic shunts. Liver ultrasound in the second one revealed dilatation of intrahepatic artery branches consistent with intrahepatic shunts, while it was normal in the third patient. Chest radiographs were normal in all three patients. Pallidal T1 hyperintensity on T1-weighted imaging may be a biomarker of manganese overload in ROW disease.     

MRI findings of hepatic alveolar echinococcosis

Diagnosis of liver infestation by alveolar echinococcosis (AE) is based on serologic, sonographic and computed tomography (CT) findings. Experience with magnetic resonance imaging (MRI) demonstrates that features of this disease are limited. CT and MRI findings of 14 cases with hepatic AE were compared in this report. We have described the MRI appearance of hepatic AE, which exhibits variable signal intensities on T1- and T2-weighted images. Fibrous and parasitic tissue showed low signal both on T1- and, generally, on T2-weighted images. In a few cases, a high signal on T2-weighted images may be observed, due either to central necrotic zones or to small peripheral cyst. MRI than by CT was more easily identified central necrosis. However, MRI seemed to be less effective than CT in allowing us to reach a positive diagnosis, due to its inability to show microcalcifications. In addition, MRI may not reveal small lesions. In most cases, T1-weighted images revealed more clearly than CT did the margins of the lesions and the hepatic extension, especially to hepatic veins, vena cava and perihepatic spaces.     

脂肪肝内正常肝岛及正常肝内局灶脂肪变性的CT与MR诊断

目的：探讨脂肪肝内正常肝岛及正常肝内局灶脂肪变性的ＣＴ与ＭＲ征象。方法：６例脂肪肝内正常肝组织岛（Ａ组）与７例正常肝内局灶性脂肪变性（Ｂ组）病人,ＣＴ与常规ＳＥＴ１ 及Ｔ２ 加权及梯度回波Ｔ１ 加权ｉｎ－ ｐｈａｓｅ及ｏｕｔ－ ｐｈａｓｅ ＭＲ成像。结果：增强前、后ＣＴ显示正常肝组织岛保持正常肝组织与脾脏密度关系;肝组织局灶脂肪变性呈相对低密度。ＭＲＩＳＥＴ１、Ｔ２ 加权成像及梯度回波ｉｎ－ ｐｈａｓｅＴ１ 加权成像显示正常肝组织岛相对低信号区;局灶脂肪变性区呈稍高信号。梯度回波ｏｕｔ－ ｐｈａｓｅ Ｔ１ 加权成像正常肝组织岛呈高信号;局灶脂肪变性区呈低信号。脂肪抑制Ｔ２ 加权成像均呈等信号。结论：采用ＭＲ的梯度回波ｏｕｔ－ ｐｈａｓｅＴ１ 加权及ＴＳＥＴ２ 加权脂肪抑制成像可以诊断正常肝岛及正常肝内的局灶脂肪变性。     

原发性骨骼肌非霍奇金淋巴瘤的影像学表现

目的 分析原发性骨骼肌非霍奇金淋巴瘤（NHL）的影像学表现，以期提高对其的认识。方法 经病理证实的原发性骨骼肌NHL5例，均为B细胞来源。其中3例有MR和CT检查，1例仅有CT检查，1例仅有MR检查。2例有X线平片，2例有核素骨显像。结果所有患者均表现为受累肌肉弥漫性肿胀，肌肉轮廓可辨。4例CT平扫密度均匀，与未受累肌肉相近；增强扫描呈轻度强化2例，中等强化1例，强化密度均匀。MR扫描4例，平扫T1WI与周围肌肉相比呈稍低信号，T2WI信号明显高于周围未受累的肌肉。肿瘤内部的信号均匀，未见明显液化坏死区。增强扫描2例肿瘤为均匀强化，强化信号明显高于周围正常肌肉信号。X线平片2例显示骨质未被破坏。核素骨显像2例显示软组织肿块浓聚，骨髓的信号未见异常。结论 原发性骨骼肌NHL的影像学表现有一定的特点，MRI是其最佳的影像学检查方法。     

The value of respiratory triggered T2-weighted turbo spin-echo imaging of the liver using a phased array coil

The purpose of this study was to evaluate the value of the respiratory triggered turbo spin-echo (TSE) technique for T2-weighted MRI of liver lesions. Fifty-nine patients (32 men, 27 women; mean age, 63.3 years) with focal hepatic lesions were prospectively studied with MRI at 1.5 T with use of a body phased array coil. In the first 15 patients, breath-hold TSE, respiratory triggered TSE, and conventional nonrespiratory triggered TSE T2-weighted imaging were compared. Because nonrespiratory triggered TSE imaging was significantly inferior (P < .01) to breath-hold or respiratory triggered images, breath-hold and respiratory triggered TSE T2-weighted images were compared in the remaining 44 patients. Images were analyzed quantitatively by measuring the liver signal-to-noise ratio and the lesion-liver and spleen-liver contrast-to-noise ratios and qualitatively by evaluating the lesion conspicuity, liver parenchymal homogeneity, and sharpness of intrahepatic vessels. The imaging time was 26 seconds for breath-hold TSE imaging, 49 to 219 seconds (mean, 149 seconds) for the respiratory triggered TSE imaging, and 79 to 379 seconds (mean, 239 seconds) for the nonrespiratory triggered TSE imaging. Quantitatively, the signal-to-noise ratio of the liver for breath-hold imaging was comparable to that for respiratory triggered imaging. The lesion-liver and liver-spleen contrast-to-noise ratios for the respiratory triggered images were greater by 37% and 39%, respectively, than for the breath-hold T2-weighted TSE images. Qualitatively, the respiratory triggered images showed lower frequency of image artifact, better lesion conspicuity, and greatly superior depiction of intrahepatic structures compared with the breath-hold T2-weighted TSE images. The respiratory triggered T2-weighted TSE technique provides better quality liver images than the breath-hold TSE technique or nonrespiratory triggered technique within a reasonable acquisition time.     

Intrahepatic extramedullary hematopoiesis: MR, CT, and sonographic appearance

A 45-year-old patient with focal intrahepatic extramedullary hematopoiesis is presented in which the liver was imaged by CT, ultrasound, and MR. The appearance of the lesions on MR consisted of slightly increased signal on T2-weighted images with heterogeneous enhancement of some of the lesions during bolus infusion of gadolinium. The T1-weighted images postgadolinium showed no delayed enhancement.     

胚胎发育不良性神经上皮瘤的影像学与临床病理特征

目的探讨胚胎发育不良性神经上皮瘤（DNT）的MRI、CT表现及临床病理特征。方法回顾性分析经组织病理学证实的12例DNT的MRI、CT表现与临床病理特点。结果男6例，女6例，年龄12～68岁（平均36．7岁）。大多数病例以癫痫小发作为主，神经系统检查无阳性体征。MR检查病变均位于幕上结构，累及皮层，额叶（4例）及颞叶（3例）为主；最大径2-5cm不等，形态呈类圆形、分叶状或不规则状；2例累及白质，7例伴囊性变。病变在MRI均呈T1WI低信号，T2WI高信号，无病变周围水肿及占位效应；囊性病变在T1WI信号均匀，等于或略高于脑脊液。6例CT扫描病变均呈低密度改变，其中2例呈囊性分叶状，1例呈局灶性钙化；4例增强后病变无强化，1例病变内呈轻度不均匀强化。病理组织学DNT分为3型：单纯型（4例）、复杂型（6例）及非特异型（2例）。结论DNT是一种良性病变，MRI较CT更具特征性表现。     

肝脏单发性囊性转移瘤的影像学表现

目的探讨肝脏单发囊性转移瘤的CT和MRI表现。方法回顾分析14例肝脏单发囊性转移瘤的CT（5例）和MRI（9例）表现。结果肝左叶5例，右叶9例。2例包膜下转移瘤呈扁丘形，其余12例呈圆形或类圆形。肿瘤直径0．7～5．5cm，平均2．7cm。病灶表现为均匀薄壁型2例，均匀厚壁型2例，不均匀厚壁型7例和分隔型3例。病灶的囊壁和分隔CT平扫呈低密度，MRI T1WI呈低信号，MRI T2WI呈高信号、无钙化。12例有强化，3例延迟增强MR扫描呈现外周冲洗现象。病灶囊内部分为水样密度或信号、无强化，3例有液平。病灶通常不伴肝硬化、门静脉栓子以及胆道扩张，但有时同时显示肝外原发肿瘤或者腹部他处转移灶。结论肝脏单发囊性转移瘤具有一定的CT和MRI特征，了解这些特征有助于此类病变的诊断与鉴别诊断。     

CT detection of basal ganglion lesions in neurofibromatosis type 1: correlation with MRI

Summary Prospective study of CT and MRI in 41 consecutive children with suspected type 1 neurofibromatosis revealed basal ganglion lesions on T2-weighted spin echo images in 22 cases (54%) and on CT in only 7 of those (32%). T2-weighted spin-echo MRI also revealed multiple signal changes in the supra- and infratentorial white matter and brain stem that went completely unnoticed on CT.     

肝脏原发性神经内分泌肿瘤影像学表现及病理对照

目的 探讨肝脏原发性神经内分泌肿瘤(PHNET)的CT、MRI表现及其病理基础.方法 收集经手术病理证实的PHNET 14例(14例均行CT检查,其中9例行MR检查),分析病灶的CT、MRI表现,探讨形成影像表现的病例基础.结果 PHNET呈单发(8例)或多发结节(5例),弥漫性全肝分布1例.CT平扫呈低密度,1例可见液-液平面病理为内部出血;动脉期呈结节状或环形强化,1例呈弥漫性强化,门静脉期或延迟期强化减低.MRI呈长T1长T2信号,出血呈短T1短T2信号,强化形式与CT相同.随病理分级的提高,病灶由G1单发实性-G2实性或囊实性-G3弥漫性分布或出现肝内转移.扩散加权成像(DWI)呈扩散受限改变.结论 CT、MRI能够显示出PHNET的影像学特殊表现和组织学特征.     

卵巢卵泡膜-纤维瘤类肿瘤的MDCT和MRI表现分析

目的：探讨卵泡膜-纤维瘤类肿瘤的 MDCT和 MRI表现。方法回顾性分析经术后病理证实的15例(16个)卵泡膜-纤维瘤类肿瘤的 MDCT(12例)和 MRI(8例)表现。结果15例共16个病灶,均为单侧,发生在右侧卵巢10例,左侧卵巢5例,1例为左侧2个肿瘤。肿瘤多为类圆形、巨大病灶呈分叶状;14个肿瘤边界光整,2个边界不清;实性肿块4个,实性为主肿块9个,囊性为主3个。肿瘤最大径在20~220 mm,平均长径为(89±58.29)mm。实性部分CT值等或略低密度,3例病灶内见斑点状钙化,平扫CT值为(40±8)HU。肿瘤实性部分轻度强化,CT值为(49±9)HU。MRI平扫肿瘤实性部分 T1 WI呈等信号5例,呈稍低信号3例;T2 WI为混杂等、稍高及高信号,呈“山间云雾”征象6例,5例见不完整包膜线,5例肿瘤包膜外缘伴随环线状高信号。8例肿瘤实性部分均为轻度延迟强化。肿瘤囊性部分呈长T1长T2信号,无强化。10例有盆腔积液(66.7%),其中13例合并子宫或卵巢其他肿瘤和囊肿(86.7%)。结论卵泡膜-纤维瘤类肿瘤的 MDCT和 MRI有一定的特征,有助于该组肿瘤的诊断和鉴别诊断。     

Castleman disease of the neck: CT and MR imaging findings

Objective

To characterize the computed tomography (CT) and magnetic resonance imaging (MRI) findings of Castleman disease of the neck.

Methods

The imaging findings of 21 patients with Castleman disease of the neck were reviewed retrospectively. Of the 21 patients, 16 underwent unenhanced and contrast-enhanced CT scans; 5 underwent unenhanced and contrast-enhanced MRI scans.

Results

The unenhanced CT images showed isolated or multiple well-defined homogenous mild hypodensity lesions in fifteen cases, and a heterogeneous nodule with central areas of mild hypodensity in one case. Calcification was not observed in any of the patients. In five patients, MR T1-weighted images revealed well-defined, homogeneous isointense or mild hyperintense lesions to the muscle; T2-weighted images showed these as intermediate hyperintense. Sixteen cases showed intermediate to marked homogeneous enhancement on contrast-enhanced CT or MR T1-weighted images. Of the other five cases that underwent double-phase CT scans, four showed mild or intermediate heterogeneous enhancement at the arterial phase, and homogeneous intermediate or marked enhancement at the venous phase; the remaining case showed mild and intermediate ring-enhancement with a central non-enhanced area at the arterial and venous phases, respectively.

Conclusion

Castleman disease of the neck can be characterized as solitary or multiple well-defined, mild hypodensity or homogeneous intense lesions on plain CT/MR scans, and demonstrates intermediate and marked enhancement on contrast-enhanced CT/MR scans. On double-phase CT scans, Castleman disease often demonstrates mild enhancement at the arterial phase, and gradually uniform enhancement at venous phase. Double-phase enhanced CT or MRI may help to differentiate Castleman disease from other diseases.     

MRI in neuro-Behçet's disease

Our purpose was to characterise specific MRI findings and to determine their value in neuro-Behçet's disease. We examined 17 patients (14 men, 3 women) with neuro-Behçet's disease using T1- and T2-weighted spin-echo images and contrast-enhanced images at 0.5 T. There were 13 patients (76.5 %) who had single or multiple lesions. Most of these were in the basal ganglia, brain stem or deep white matter region, giving high signal on T2-weighted images and isointense or low signal on T1-weighted images. In 3 cases (17.6 %) there was linear high signal along the posterior limb of the internal capsule on T2-weighted images. This was considered as a potential differentiating feature of neuro-Behçet's disease. Contrast-enhancement was seen in 17 lesions in 7 patients.     

Amebic liver abscess: MR imaging

Hepatic magnetic resonance (MR) imaging was performed in 12 patients with 13 amebic liver abscesses. While no specific image or intensity pattern was noted, most lesions were round or oval with smooth, well-defined margins; had decreased signal intensity compared with that of liver parenchyma on T1-weighted images and increased signal intensity on T2-weighted images; and had prominent, often multiple rims of variable signal intensity. Signal homogeneity within the abscess was present more often on T1- than on T2-weighted images. Diaphragmatic disruption was seen in two cases on coronal MR images. An amebic empyema was differentiable from sympathetic pleural effusions by its hyperintensity on both T1- and T2-weighted images. In patients who also underwent computed tomography (CT) or ultrasonography (US), no lesion was missed with any modality, and except for shape, no consistent features were found among images obtained with the different modalities. The data suggest that CT, US, and MR imaging are comparably effective in the detection of amebic abscess.     

Multiple biliary hamartomas: magnetic resonance features with histopathologic correlation

The purpose of this study was to report the magnetic resonance imaging (MRI) features of multiple biliary hamartoma (MBH) and to correlate them with histopathology. MRI features of 11 patients with MBH proven by histology were retrospectively reviewed and correlated to histopathology. MBH presented as multiple, tiny, and uniformly distributed lesions in all cases. All were hypointense on T1-weighted images and hyperintense on T2-weighted images relative to the liver parenchyma. Mural nodules were identified in 10 of 11 (91%) cases. They were isosignal on T1-weighted images, intermediate signal on T2-weighted images. Gadolinium-enhanced images showed mural nodule enhancement in 9 of 10 patients (90%) or a peripheral rim-like enhancement of the whole lesion in one case (9%). MBH were present in all liver specimens. In the six patients examined at MR cholangiography, the lesions lacked communication with the biliary tree. At histopathology, the mural nodule corresponded to an endocystic polypoid projection made of conjunctive septa. Three (27%) patients had associated focal nodular hyperplasia, and 1 (9%) had concomitant cholangiocarcinoma. MRI features allowed diagnosis of MBH with accuracy. Their recognition, especially the mural nodule, may help avoid misdiagnosis.     

Lipomatous lesions of the head and neck region: imaging findings in comparison with histological type

PURPOSE: Aim of the study is to demonstrate the main role of magnetic resonance imaging in the identification and characterization of lipomatous lesions of the head and neck. MATERIALS AND METHODS: CT and MRI findings of 78 patients (43 male, 35 female) aged 12-80 (mean 47.5) years surgically treated for lipomatous lesions of the head and neck region between January 1995 and June 2005 were retrospectively analysed and correlated with the histological results. RESULTS: On CT images, lipomas and fibrolipomas appeared as smooth (38/50 cases) or lobulated (12/50 cases) well-defined masses associated with moderate displacement of surrounding tissues; tumours had high signal intensity on MR T1-weighted images, with relative decreasing signal on T2-weighted images. Infiltrating lipomas appeared as expansile ill-defined masses with heterogeneous signal. Angiolipomas showed a characteristic contrast enhancement on both CT and MRI. In one case of sialolipoma, the lesion appeared markedly heterogeneous in signal. MR and CT images of Madelung's disease showed multiple symmetrical lipomatous masses involving the neck region. Intraosseous fatty lesions appeared as well-defined hypodense masses sometimes associated with cortical expansion and disruption. CONCLUSIONS: Both CT and MRI exams are useful for detecting lipomatous lesions. MRI, however, is more accurate in the evaluation of their extent and in the characterisation of uncommon lipomatous lesions of the head and neck, and intravenous administration of gadolinium better depicts the margins of the tumour and its vascularisation.     

CT and MR appearance of focal nodular hyperplasia of the liver in children with biliary atresia

Two children with biliary atresia are described in whom focal nodular hyperplasia of the liver occurred following portoenterostomy. The lesions were low-or iso-dense on unenhanced CT and became hypodense post-contrast enhancement. There was normal 99mTc phytate on hepatic colloid scintigraphy. On T2-weighted spin echo MR images, there was increased signal intensity within the masses, and the surrounding liver parenchyma was divided by linear septa in one of the two cases.     

Early-enhancing non-neoplastic lesions on gadolinium-enhanced MRI of the liver

AIM: To assess the frequency, cause, and significance of early-enhancing, non-neoplastic (EN) lesions on gadolinium-enhanced magnetic resonance imaging (MRI) of the liver performed for the detection of malignant hepatic tumours. MATERIALS AND METHODS: From September 1997 to September 2000, we reviewed the images of 125 patients, suspected of having hepatic tumours, in whom (1) gadolinium-enhanced triphasic dynamic gradient-recalled-echo (GRE) imaging in addition to unenhanced T1- and T2-weighted MRI was performed, (2) conventional angiography and combination computed tomography (CT) hepatic arteriography and CT during arterial portography were performed within 2 weeks of the MRI, and (3) definitive surgery within 2 weeks of the MRI or follow-up study by means of intravenously contrast-enhanced CT or MRI in 10 months or more was performed. Angiographic studies were correlated to determine the underlying causes of the EN lesions. RESULTS: We found 78 EN lesions in 36 patients (29%), ranging in size from 4 and 50 mm (mean, 12.2 mm). From the MR reports, our radiologists had prospectively diagnosed EN lesions as probable malignant tumours in eight (10%), possible malignant tumours in 36 (46%), and probable non-neoplastic lesion in 34 (44%). EN lesions were found in 27 of 81 (33%) cirrhotic patients and in nine of 44 (20%) non-cirrhotic patients. Fifty-one EN lesions (65%) were located along the liver edge. The shape was circular in 42 (54%), oval in 14 (18%), irregular in 12 (15%), wedge-shaped in seven (9%), and fan-shaped in three (4%). Twenty EN lesions (26%) appeared slightly hyperintense on T2-weighted images. The causes were non-neoplastic arterio-portal shunting in 48 (62%), cystic venous drainage in four (5%), rib compression in four (5%), aberrant right gastric venous drainage in two (3%), and unknown in 20 (26%). CONCLUSION: Over half the number of EN lesions were caused by non-neoplastic arterio-portal shunting, occasionally showing slight hyperintensity on T2-weighted images. On MR images the non-neoplastic nature of the EN lesion was often ascertained. Radiologists should not overcall EN lesions as malignant as the patients involved would be inappropriately considered inoperable. In problematic cases, further investigation with angiographic CT or follow-up imaging studies should be performed.     

肝脏局灶性结节增生的螺旋CT和MRI诊断

目的 :分析肝脏局灶性结节增生 (FNH)平扫和动态增强的螺旋CT、MRI表现 ,提高FNH诊断符合率。方法 :对 13例经手术病理证实的FNH影像学表现进行回顾性分析。螺旋CT检查 8例 ,MRI检查 6例 ,其中 1例同时做CT和MRI检查。结果 :8例CT平扫病灶均呈低密度 ,均匀或不均匀。增强动脉期扫描除中心疤痕外 ,所有病灶均有明显均匀强化 ,其中 4例还可见到病灶中心或周边增粗、扭曲的动脉。门脉期和延迟期扫描 4例呈略高密度、4例病灶呈等密度或略低密度 ,4例伴有中心疤痕者均有延迟强化。MRI检查 6例 ,病灶均呈不均匀略长或等T1及T2 信号 ,增强动脉期呈明显强化 ,门脉期及延迟期呈等或略高强化 ,4例MRI平扫显示中央瘢痕者有延迟强化。结论 :平扫和动态增强螺旋CT、MRI能较全面显示FNH的病理特征和血供特点 ,明显地提高与其它富血管恶性肿瘤的鉴别诊断能力     

Segmental intensity differences in the liver on MR images: a sign of intrahepatic portal flow stoppage

Segmental intensity differences (SIDs) in hepatic parenchyma free of tumor were noted in six patients with hepatic masses (hepatocellular carcinoma in five and metastatic liver cancer in one). Areas of SID were homogeneous in intensity. The intensity of the affected region was high in all six patients on T2-weighted magnetic resonance (MR) images and low in two on T1-weighted images. Three of five patients examined with plain computed tomography (CT) had corresponding segmental areas of low attenuation. Angiograms obtained in five patients showed occlusion of the intrahepatic portal vein, segmental staining corresponding to the region of the SID, or both. Twelve of 82 patients examined with MR imaging and angiography had similar findings on angiograms, and ten of them had abnormal intensity of anatomic distribution around or beside the liver tumors on MR images. MR imaging may be more sensitive than plain CT in the detection of secondary changes caused by intrahepatic portal flow stoppage.