MR imaging of soft-tissue hemangiomas: correlation with pathologic findings

Soft-tissue hemangiomas have been described in MR imaging, but a histopathologic correlation to better understand the MR appearance has not been reported. Five patients with intramuscular soft-tissue hemangiomas were imaged in orthogonal planes on a 1.5-T system with spin-echo (SE) short-TR/TE sequences (600/20) and long-TR/TE sequences (2500/20-80). Complete intact surgical specimens were obtained, and gross and histopathologic findings were compared with MR findings. A striated-septated configuration with a high signal intensity on long-SE sequences (TE greater than 75 msec) correlated with endothelial-lined vascular channels separated by fibrous and/or fatty linear strands. An awareness of the morphologic MR pattern of soft-tissue hemangiomas may aid in recognition of these lesions.     

Epithelioid hemangioendothelioma of the liver: imaging findings with pathologic correlation.

Hepatic epithelioid hemangioendothelioma is a rare malignant neoplasm that has nonspecific clinical signs and symptoms and can be difficult to diagnose on the basis of biopsy results. Radiologists may suggest the diagnosis of this slowly progressive neoplasm by recognizing its characteristic radiologic features. We correlated images from CT (13), sonography (nine), and MR (six) with pathologic findings in resected whole livers (eight) and biopsy specimens (five) from 13 patients 25-58 years old. Gross pathologic examination showed a repetitive pattern of multiple solid tumor nodules, in a predominantly peripheral distribution, with coalescence as individual nodules exceeded 4 cm. Tumor nodules had a hyperemic rim. Lesions adjacent to the capsule often produced capsular retraction. These findings correlated well with imaging findings. On CT, the lesions were of low attenuation, peripherally based, and with capsular retraction or flattening in nine (69%) of 13 patients. Unenhanced CT scans showed superior conspicuity over contrast-enhanced CT scans (9/13, 69%) and showed the extent of lesions more accurately in all cases (13/13, 100%). In nine patients, lesions had a peripheral enhancement pattern of alternating attenuation values correlating with the hyperemic rim at pathologic evaluation. On sonograms, the tumors were solid and predominantly hypoechoic. On MR, tumor signal was low on T1-weighted and high on T2-weighted images, with a low-signal halo present around many of the lesions. CT, sonographic, or MR findings of coalescent peripheral hepatic masses with capsular retraction are highly suggestive of hepatic epithelioid hemangioendothelioma.     

肝衰竭的CT影像表现及病理对照

目的 探讨肝衰竭肝坏死和再生的CT影像表现.方法 回顾件分析5例肝衰竭患者原位肝移植术前的CT表现,并与术后的人体标本和病理结果 相对照,分析其影像特征.结果 肝衰竭的CT影像表现有3种:(1)大块状融合病灶2例:病理结果 分别为肝细胞的大块状坏死和聚合的结节样再生.CT平扫相应表现为地图样分布的低密度和高密度区;增强扫描肝内坏死区强化出现在静脉期,聚合的肝细胞结节样再生以动脉期强化明显.(2)弥漫的结节状病灶2例:病理结果 分别为肝内弥漫的结节状坏死和结节状再生.CT平扫均表现为弥漫的稍高密度结节灶;增强扫描动脉期均出现强化,前者静脉期及延迟期表现为结节状低密度灶,后者静脉期及延迟期表现为等密度改变.(3)多发小片状病灶1例:病理为肝内分散的肝细胞小片状坏死.平扣肝脏密度弥漫性减低;增强扫描静脉期表现为肝周的小片状强化,动脉期及延迟期为等密度改变.结论 肝衰竭的CT影像表现具有特征性.

Abstract：

Objective To investigate CT findings of hepatic necrosis and regeneration after liver failure.Methods Five patients with liver failure underwent CT scan before orthotopic liver transplantation.These findings were retrospectively reviewed and correlated with gross specimen and pathologic findings obtained after transplantation.Results Among 5 cases,the CT appearances of liver failure can be divided into 3 types.(1)Massive confluent aggregate foci in 2 patients demonstrated low attenuation and high attenuation as geographical patlerns on CT scans before contrast enhancement.respectively.The histopathological liver changes showed massive necrosis and regencratinn. Regions of necrosis enhanced to attenuation greater than that of normal liver parenchyma in portal-venous phase,the regions of regeneration enhanced to attenuation greater than that of normal liver parenchyma in arterial phase on postcontrast CT images.(2)In 2 patients,diffuse nodules of liver demonstrated high attenuation on plain CT scans,which was nodular necrosis and nodular regeneration pathologically.All enhanced to attenuation greater than that of normal liver parenchyma in arterial phase.The former showed hypointensity in portal-venous phase and equilibrium phase.The latter enhanced to attenuation equal to that of normal liver parenchyma in portalvenous phase and equilibrium phase on postcontrast CT images.(3)Multiple small foci in 1 case demonstrated low attenuatiun on precontrast CT images and enhanced to hyperintensity in portal-venous phase and isointensity in arterial phase and equilibrium phase on postcontrast CT images.The histopathological liver changes showed multiple necrosis.Conclusion Liver failure may reveal characteristic imaging patterns at CT.     

小儿腹膜后成神经细胞瘤影像学与病理的对照研究

目的 探讨ＣＴ、ＭＲＩ对小儿腹膜后成神经细胞瘤的诊断价值和限度。方法 对３２例中２０例术前同时行ＭＲＩ、ＣＴ检查者与术中所见对照,并对其中１９例术后离体肿瘤的ＭＲＩ、ＣＴ影像与病理大切片对照。结果 ＭＲＩ表现一般为Ｔ１Ｗ１中低信号,Ｔ２Ｗ１明显高信号,且可见低信号网格及肿瘤对血管的包绕。组织学基础：原始成神经细胞核大密集,无间质;瘤巢周围有神经纤维。ＣＴ表现肿瘤为不均匀低密度,可见钙化。术前判断肿     

Imaging of carcinoid tumors: spectrum of findings with pathologic and clinical correlation

Carcinoid tumors are primary malignant neoplasms that arise from neuroendocrine cells. These cells are located throughout the body, resulting in many possible locations for the development of carcinoid tumor. The most common primary location is the gastrointestinal tract, followed by respiratory and thymic carcinoids. The presentations of these tumors are variable depending on their location, aggressiveness, production of functional peptides, and tendency to invade or metastasize. Carcinoid tumors can be imaged by various modalities including gastrointestinal studies, ultrasound, computed tomography, and magnetic resonance imaging as well as nuclear medicine studies (radioactive octreotide). In this review, we illustrate the spectrum of imaging features of carcinoid tumors in various locations of the human body.     

Regenerating nodules of liver cirrhosis: MR imaging with pathologic correlation

To determine the pathologic basis for low-intensity nodules seen on MR images of the liver in patients with cirrhosis, we obtained spin-echo and gradient-echo MR images in 20 cirrhotic patients in whom partial hepatectomies were subsequently performed for hepatocellular carcinoma. Low-intensity liver nodules were shown on gradient-echo and spin-echo images in eight patients. Pathologic study of the liver in these patients showed that these nodules were regenerating nodules containing hemosiderin. Low-intensity nodules were seen only on T2-weighted spin-echo images in four other patients. Microscopic examination of the liver in these patients showed regenerating nodules without hemosiderin deposits. Broad fibrous septa containing vascular spaces were present in two of these four patients. These results suggest that regenerating nodules containing hemosiderin or those that are surrounded by vascular fibrous septa are visible on MR images as low-intensity nodules and that gradient-echo images are useful in demonstrating nodules with hemosiderin.     

Chondroblastoma: MR characteristics with pathologic correlation.

PURPOSE: The purpose of this study was to describe the MR findings of chondroblastoma with pathologic correlation. METHOD: In 22 patients with pathologically proven chondroblastoma, MR signal characteristics were correlated with pathological findings. RESULTS: On T2-weighted images, 12 (55%) lesions were hyperintense with hypointense areas in 9 lesions, whereas 10 (45%) were hypointense. Therefore, 19 of 22 (86%) lesions with pathologic correlation had hypointense areas entirely (n = 10) or partly (n = 9) on T2-weighted images. On gadolinium-enhanced images, 13 (59%) lesions showed lobular enhancement and 9 (41%) showed marginal and septal enhancement. Low signal intensity on T2-weighted MR images was most strongly associated with an abundance of immature chondroid matrix, hypercellularity of the chondroblasts, calcifications, and hemosiderin on histology. CONCLUSION: Chondroblastoma was found to show hypointense portions on T2-weighted images. Signal intensity on T1- and T2-weighted MR images in chondroblastoma was dependent on the amounts of histopathological components.     

Chondrosarcoma: MR imaging with pathologic correlation.

Magnetic resonance (MR) images of 21 surgically confirmed chondrosarcomas were retrospectively reviewed in conjunction with plain radiographs and computed tomographic scans and correlated with pathologic findings. The tumors appeared lobulated, and signal intensity, as analyzed visually (intermediate on T1-weighted, high on T2-weighted images), was similar for all lesions, regardless of pathologic type. Size of lesion was not an indicator of grade. The appearances of mesenchymal and dedifferentiated chondrosarcomas mimicked that of conventional chondrosarcoma. Extraskeletal chondrosarcoma was visualized as a lobulated soft-tissue mass. In all cases, MR imaging accurately depicted intraosseous and soft-tissue extent of tumor noted at surgery and pathologic examination. Histologic type or grade of chondrosarcoma generally cannot be characterized on the basis of visual analysis of signal intensity noted on routine MR images. However, MR imaging is excellent for exact delineation of tumor extent.     

肝脏局灶性结节增生的MRI与病理对照性分析

目的:研究肝脏局灶性结节增生(FNH)的MRI表现和病理学表现及其它们的相关性。方法:回顾性分析9例经手术病理证实的FNH的MRI表现及其病理学表现。结果:FNH平扫T1WI 5例为等信号,4例为稍低信号;T2WI 3例为等信号,6例为稍高信号。7例病灶中心或偏心有瘢痕。动态增强扫描9例病灶在动脉期均呈明显均匀强化;门脉期和延迟期为轻度增强或等信号;7例病灶在延迟期出现瘢痕强化。FNH是多血供实质性肿块,肿瘤内部结构均匀,出血和坏死少见,镜下可见典型的星状瘢痕。结论:MRI平扫和动态增强扫描能够显示FNH的特征性表现,反映FNH的病理特点,提高FNH的确诊率。     

肝脏局灶性结节增生的典型与非典型MR表现及其病理基础

目的:研究肝脏局灶性结节增生(FNH)的典型与非典型MR表现及其病理基础,探讨MRI对各型的诊断价值。方法:分析经手术病理证实的FNH 28例(36个病灶)的典型与非典型MR表现,并与病理结果相对照。结果:①典型表现20例(28个病灶),大小在2.0~10.5cm,T1WI上呈等/稍低信号,T2WI上呈等/稍高信号,增强扫描动、门脉期病变呈显著增强,延迟扫描呈等/略高信号,中心瘢痕出现率占42.9%(12/28例),于T1WI上呈低信号,T2WI上呈高信号,增强扫描呈延迟强化。组织学上有特征性的中央纤维瘢痕,由纤维结缔组织和扭曲的血管组成,并向外放射状形成许多纤维间隔,纤维间隔旁围绕以无明显异形性的肝细胞形成硬化样结节;②非典型表现8例(8个病灶),大小在1.5~8.5cm,T1WI呈略高或低信号,T2WI呈不均匀高信号,增强扫描病灶强化不显著、不均匀,病灶内未见中心瘢痕或瘢痕不强化,出现假包膜等。镜下病变内毛细胆管扩张,其内纤维分隔较短、不连续,部分较大病灶内有出血、脂肪变及坏死,但无异型性肝细胞。结论:MRI能很好反映肝脏局灶性结节增生的典型与非典型表现的病理基础,具有高度的诊断特异性。     

原发性非黏液瘤性心脏心包肿瘤影像学诊断(附30例手术病理对照)

目的 分析原发性非黏液瘤性心脏心包肿瘤影像学特征,评估几种影像诊断方法的主要优势及其局限性。方法 搜集术前有完整的临床、X线平片及超声诊断资料并经手术病理证实的原发性非黏液瘤性心脏心包肿瘤30例,其中接受MRI检查者14例、电子束CT（EBCT）10例。结果 X线平征示异常17例,包括肺淤血5例、心缘不规则3例、“怪异形”3例、合并心包积液5例、钙化1例。超声心动图（UCG）诊断正确22例,其中腔内肿瘤11例全部诊断正确;心包肿瘤10例,诊断正确8例;壁在性肿瘤9例,诊断正确者仅3例。MRI和CT诊断均正确。结论 心脏肿瘤应采用影像学综合诊断。X线只用于初步检查;心腔或心包腔内的肿瘤应优先 选择UCG;壁在性肿瘤或腔 外侵犯需结合MRI或（和）EBCT,MRI还能够对脂肪瘤、纤维瘤和心包囊肿伴出血等作出初步的组织学定性诊断。     

Atypical tumors of the rectum with pathologic correlation

Although the majority of rectal masses are histologically characterized as adenocarcinoma, there is a wide spectrum of rare, but specific, neoplastic processes that can involve the rectum and present with rectal bleeding. Knowledge of their existence and protean imaging features is crucial for accurate diagnosis and appropriate management. This review article describes the clinical, imaging, and histopathologic characteristics of several pathologically proven rectal lesions, including rectal carcinoid, rectal gastrointestinal stromal tumor, rectal cavernous hemangioma, primary anorectal melanoma, primary rectal lymphoma, and rectal metastases.     

Metastatic adenocarcinoma to the brain: MR with pathologic correlation.

PURPOSETo describe the appearance on T2-weighted scans of metastatic adenocarcinoma to the brain and to show that the hypointensity frequently associated with these lesions is not related to the presence of mucin, blood products, iron, or calcium.METHODSThe MR scans of 14 patients with metastatic adenocarcinoma to the brain were reviewed retrospectively. The signal intensity on T2-weighted scans of the solid enhancing portion of the tumors was compared with white matter. Histologic examination of the surgical specimens included special stains to search for calcium, mucin, and iron.RESULTSEight of nine surgical and all six nonsurgical lesions were either iso- or hypointense to white matter on T2-weighted scans. There was no correlation with tumor histology or the presence of mucin, blood products, iron, or calcium.CONCLUSIONSThe presence of a hypointense intraaxial mass on T2-weighted scans strongly suggests the possibility of metastatic adenocarcinoma. The MR appearance is not explained by the presence of mucin, blood products, iron, or calcium. This phenomenon most likely reflects the relaxation parameters of the tissue from which the metastasis arose.     

MRI of atypical focal nodular hyperplasia of the liver: radiology-pathology correlation

OBJECTIVE: The purpose of our study was to determine the MRI features of atypical focal nodular hyperplasia of the liver and to compare them to pathology findings. MATERIALS AND METHODS: We retrospectively reviewed MRI and pathology findings in 27 focal nodular hyperplasia lesions with atypical MRI features. Six criteria for typical focal nodular hyperplasia were required: iso- or hypointensity on T1-weighted sequences and iso- or slight hyperintensity on T2-weighted sequences; homogeneous signal intensity; central hyperintense area on T2-weighted sequences; marked lesion contrast enhancement; accumulation of gadolinium chelates within the central area on delayed contrast-enhanced T1-weighted sequences; and absence of capsule. RESULTS: The most common atypical radiology features included absence of, or an atypical, stellate area; heterogeneity on both T1- and T2-weighted images; and high-intensity signal on T1-weighted sequences. MRI-pathology correlation showed that T1 hyperintensity with no other atypical MRI feature (n = 3) could be explained by steatosis, sinusoidal dilatation, or hemorrhage. In addition, in two patients with lesions smaller than 3 cm in diameter, the only atypical MRI feature was absence of a stellate area. CONCLUSION: These findings suggest a lesion that is hyperintense on T1-weighted sequences or that lacks a stellate area but is smaller than 3 cm in diameter can be diagnosed as focal nodular hyperplasia provided all other MRI criteria for this diagnosis are present. In such cases, close monitoring on MRI without invasive diagnostic procedures may be warranted. However, in large lesions (> 3 cm) without a stellate area and in lesions with heterogeneity, histopathology examination is mandatory to rule out other diagnoses.     

Focal lesions in the cirrhotic liver: high resolution ex vivo MRI with pathologic correlation

Cirrhosis is a progressive, diffuse process of liver fibrosis that is characterized by architectural distortion and the development of a spectrum of nodules ranging from benign regenerative nodules to premalignant dysplastic nodules to overtly malignant hepatocellular carcinoma. The purpose of this essay is to demonstrate the ex vivo MR and pathology findings of these nodules as well as other masses that can be seen in the cirrhotic liver. The optimal conditions under which ex vivo imaging can be performed allow greater spatial resolution than that achieved with in vivo imaging, without artifacts that may degrade image quality. Clearly, contrast-enhanced MRI is essential for both the diagnosis and the characterization of focal lesions in the cirrhotic liver. However, the use of ex vivo imaging precludes the evaluation of these important in vivo pulse sequences.