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 peripheral nerve sheath tumors with pathologic correlation: pictorial review

Peripheral neurogenic tumors include neurilemoma, neurinoma, and malignant peripheral nerve sheath tumors. All neurogenic tumors share common imaging features. Although differentiation between them is difficult, neurogenic origin can be suggested from their imaging appearances, including fusiform shape, relation to the nerve, "split-fat" sign, associated muscle atrophy and intrinsic imaging characteristics including "target sign" as well as from lesion location along a typical nerve distribution. Our purpose is to make an overview of imaging findings of each type of peripheral nerve sheath tumor with emphasis on characteristic signs and correlate with histologic features. Morton's neuroma and intraneural ganglion are also included as tumors of nerve origin.     

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.     

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.     

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。     

Pediatric liver neoplasms: a radiologic–pathologic correlation

Only 1–2 % of all pediatric tumors occur in the liver. Two thirds of these tumors are malignant and almost all of the tumors cause clinical symptoms due to their mass effects. Besides the poor prognosis in most of the malignant tumors, for further treatment the origin and nature of the neoplasm has to be known. Due to the mostly unimpeded growth into the peritoneal cavity, the origin of the tumors is primarily often unclear and can non-invasively only be determined by advanced imaging techniques. The display of the macro- and microhistological key features of primary pediatric liver neoplasms, including hepatoblastoma (HB), infantile hemangioendothelioma (IHE), mesenchymal hamartoma (MH), undifferentiated (embryonal) sarcoma (UES), and hepatocellular carcinoma (HCC), together with their imaging representation by ultrasound, computed tomography, and magnetic resonance imaging, may deepen the understanding of the underlying pathology and its imaging appearance. Furthermore, in many cases sufficient information may be provided not only to differentiate benign from malignant tumors, but also to guide for adequate treatment. Received: 28 September 1998; Revision received: 22 December 1998; Accepted: 23 December 1998     

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。     

Typical and atypical liver hemangiomas… Can diffusion MR with different b values provide confident diagnosis?

The aim of this work was to evaluate the ability of Diffusion MRI using different b values in detection and characterization of liver hemangiomas in order to differentiate them from other focal hepatic lesions.Patients and methodsThirty one hemangiomas in 28 patients were examined with diffusion MR using different four b values: 200, 500, 800 and 1000 s/mm². Hemangiomas were divided into typical and atypical lesions. Lesions were evaluated regarding size, enhancement pattern, signal intensity and ADC maps in conventional and diffusion MR.ResultsAll hemangiomas showed hyperintense signal at diffusion MR with different b values. In typical and atypical hemangiomas, diffusion MR showed hyperintense signal that persisted with increasing b values. Both types showed hyperintense signal or mixed signals in ADC maps. Mean ADC values (for both types) were 2.47, 2.36, 2.31 and 2.10 × 10^?3 mm²/s for b 200, 500, 800 and 1000, respectively. Arterial nodular enhancement pattern of atypical hemangiomas showed significant increased ADC value than other types.ConclusionDWI can successfully detect and characterize hepatic hemangiomas, it provides qualitative and quantitative assessment of hemangiomas. The combination of diffusion signal intensity and ADC maps and values successfully differentiates hemangiomas from other focal lesions rather than signal intensity changes in different b values.     

Undifferentiated (embryonal) sarcoma of the liver: radiologic- pathologic correlation

Undifferentiated (embryonal) sarcoma (UES) is an uncommon malignant mesenchymal hepatic tumor that occurs in older children and young adults. Fourteen cases are correlated with radiologic and pathologic findings. Radiologic findings reflect the spectrum of solid to cystic appearances observed in the gross specimens. Sonography typically demonstrates a large mass that may be predominantly solid with many small anechoic spaces or may be cystic. Computed tomography reveals a hypodense mass with hyperdense septa of variable thickness and a dense peripheral rim corresponding to the fibrous pseudocapsule of the tumor. Angiographically, UES is usually hypovascular with tumoral vessels, although hypervascular and avascular patterns occur. Prognosis of UES is poor, with a median survival of less than 1 year. Radiologists should be familiar with this malignant tumor since it may present as a large cystic hepatic mass, suggestive of a benign lesion.