Bile duct involvement in hepatocellular carcinoma: MR demonstration

Background: To determine the magnetic resonance (MR) features of hepatocellular carcinoma (HCC) with associated bile duct involvement. Methods: MR examinations of six patients (mean age, 62 years) demonstrating bile duct involvement due to HCC were retrospectively reviewed and compared to surgical and pathologic findings. Results: Three of the tumors were solitary, and three were multifocal. In two patients, MR showed direct biliary duct invasion by tumor. On T1-weighted MR images, four tumors were hypointense compared to the liver and two were isointense. On T2-weighted MR images, four tumors were hyperintense, and two were isointense. The two tumors studied with dynamic T1-weighted MR images obtained after intravenous administration of a gadolinium chelate, displayed enhancement similar to that of the liver. There was no evidence of a tumor capsule on either unenhanced or enhanced MR images. Intrahepatic bile duct dilatation was seen in five patients. The extrahepatic bile duct was normal in all cases. Conclusion: Although rare, HCC should be included when considering the etiology of intrahepatic bile duct obstruction. Imaging features suggestive of the diagnosis by MR include intrabiliary tumor or bile duct obstruction with an associated hepatic mass.     

Magnetic resonance imaging features of a solitary fibrous tumor of the vulva: a case report

Solitary fibrous tumors (SFTs) are commonly seen in the pleura. SFT involvement of the vulva is rare, and clinical diagnosis is mainly based on histopathological and immunohistochemical analyses. We herein describe the imaging features of a 69-year-old woman with an SFT of the vulva. The SFT was hypointense on T1-weighted images, similar to muscle; however, it showed inhomogeneous hyperintensity predominantly on fat-suppressed T2-weighted images. An area of low signal intensity was evident on T2-weighted images, and the tumor showed progressive enhancement in delayed phases. The tumor also displayed heterogeneous and prolonged, persistent enhancement, and serpentine vessels were present in the peritumoral area as signal voids. Pathological examination confirmed that the lesion was an atypical SFT originating from the vulva, and it was composed of spindle cells and perivascular and stromal hyalinization. This case reveals the characteristic imaging findings of vulvar SFT and their association with the relevant pathological findings, thus contributing to the primary diagnosis and preoperative evaluation of this potentially aggressive tumor.     

MR imaging of hepatocellular carcinomas with biliary tumor thrombi

We retrospectively evaluate the MR imaging findings of hepatocellular carcinomas (HCC) with biliary tumor thrombi. MR imaging was performed on six patients presenting with obstructive jaundice and/or biliary hemorrhage. T1-weighted images, T2-weighted images, MR cholangiopancreatography (MRCP), and dynamic MR images were obtained. Duodenal endoscopy was performed on all cases and hepatic resection on two cases. HCCs were 1.8–10 cm in diameter (mean 5.8 cm). Biliary tumor thrombi were detected in all patients on MR imaging. Tumor thrombi showed hypointensity on T1-weighted images, hyperintensity on T2-weighted images, and contrast enhancement on the early phase of dynamic MR images. MRCP showed intrahepatic bile duct dilatation in all cases. Biliary hemorrhage was clearly depicted by MR images in five cases and showed hyperintensity on T1-weighted images and hyperintensity or hypointensity on T2-weighted images. Biliary hemorrhage was confirmed by endoscopy in two cases. Portal vein thrombi were also associated in five of six patients. Pathologically, tumor thrombi of HCCs were demonstrated in two patients who underwent hepatic resection. In conclusion, MR imaging is useful for the diagnosis of biliary tumor thrombi from HCC and for evaluating the extension of thrombi and biliary hemorrhage.     

Plain and gadolinium-DTPA-enhanced MR imaging of hepatocellular carcinoma treated with transarterial chemoembolization

Background: To assess unenhanced and gadolinium-enhanced magnetic resonance (MR) imaging patterns of hepatocellular carcinoma (HCC) treated with transarterial chemoembolization (TACE). Methods: Thirty-two patients with 48 HCC lesions underwent MR imaging before and 15 days after TACE. Fifteen lesions were then surgically resected. The remaining 33 lesions were not removed and were followed up with MR imaging at 3, 6, 12, and 18 months after treatment. Spin echo (SE) T1- and T2-weighted and gadolinium-enhanced SE T1-weighted sequences were employed. Qualitative evaluation of signal intensity pattern of the treated lesions was performed in all cases. Histological evaluation and selective hepatic arteriography were considered the gold standard of the study for the 15 resected lesions and the 33 unresected lesions, respectively. Results: On follow-up enhanced T1-weighted images of the 15 resected lesions, seven showed no area of enhancement corresponding to complete necrosis at histologic examination. The remaining eight resected lesions showed areas of enhancement; in six of these cases, viable tumor tissue was found at histology; in the other two lesions, histologic examination revealed the presence of complete tumor necrosis. In the group of resected lesions, T2-weighted images showed no pattern characteristic of necrosis. In 24 of 33 unresected lesions, loss of enhancement on follow-up enhanced T1-weighted images was a characteristic finding, which correlated to devascularization at arteriography. Of these 24 lesions, 17 were completely hypointense on follow-up T2-weighted images; the remaining seven showed small foci of hyperintensity. The other nine unresected lesions showed enhanced portions on follow-up enhanced T1-weighted images, which corresponded to hyperintense areas on T2-weighted images. These findings correlated to persistence of hypervascular areas at arteriography. Conclusion: Gadolinium-enhanced T1-weighted MR imaging is a reliable method for evaluating the outcome of TACE treatment and is more accurate than unenhanced T2-weighted MR imaging. Received: 2 June 1995/Accepted: 18 July 1995     

Hepatic metastases of soft tissue angiosarcoma: CT and MR imaging findings

Background: We describe the computed tomographic (CT) and magnetic resonance imaging (MRI) findings of hepatic metastases caused by soft tissue angiosarcomas to clarify the relation between radiologic appearances and clinicopathologic features.Methods: CT and MR examinations of 13 patients with hepatic metastases of soft tissue angiosarcoma were retrospectively analyzed.Results: Contrast-enhanced CT images showed multiple hypoattenuating lesions relative to the adjacent liver parenchyma. Lesions contained peripheral areas of enhancement in eight patients (62%). Tumors showed cystic attenuation with fluid–fluid levels, which were suggestive of hemorrhage in five patients (38%). In one patient (8%) with cystic attenuation and fluid–fluid levels, lesions also contained marked enhanced nodular portions located centrally or peripherally. On T1-weighted MR images, all four liver tumors appeared heterogeneous and hypointense relative to adjacent liver parenchyma. Fluid–fluid levels were identified on T2-weighted MR images in five patients (38%). After an intravenous bolus of gadolinium-based contrast material was administered, slight peripheral enhancement was seen in three patients (75%).Conclusion: The common CT findings of metastatic angiosarcoma in our series were multiple hypoattenuating lesions often associated with nodular enhancement and cystic lesions with hemorrhagic change.     

腹盆部孤立性纤维瘤的影像学表现

目的探讨腹盆部孤立性纤维瘤(SFT)的CT及MRI特点,提高对该病的认识。方法回顾性分析14例经手术病理证实的腹盆部SFT的CT及MRI平扫及增强表现,并与病理对照。结果 14例SFT中,肝脏2例,胰腺1例,腹壁2例,腹腔内4例,盆腔5例。肿物边界清楚10例,不清4例。11例行CT扫描,9例密度不均匀,2例密度均匀,8例多期增强扫描均于门脉期强化达峰值并持续性强化或缓慢下降。3例MRI检查均信号不均匀,T_1WI等信号1例,稍低信号2例,T_2WI稍高信号2例,稍低信号1例,增强扫描均见持续强化。SFT的相对特征性表现为腹部及盆腔孤立性肿块,边界清楚,见明显坏死囊变,T_2 WI上病灶内见低信号影,增强扫描实性部分明显强化,呈持续性或延迟强化。结论腹盆部SFT影像学表现多种多样,具有一定的特征性,确诊仍需病理学及免疫组织化学检查。     

MR imaging of intrahepatic cholangiocarcinoma

Background: The purpose of this study was to determine the magnetic resonance (MR) features of intrahepatic cholangiocarcinoma. Methods: MR imaging studies of seven cases of pathologically proven intrahepatic cholangiocarcinoma were retrospectively reviewed. Results: On MR images the tumors presented as a single mass (N = 5) or multiple nodules (N = 2), as welldelineated (N = 5) or ill-defined (N = 2), and as non-encapsulated (N = 7). Mean tumor diameter ranged from 6–14 cm (mean, 10 cm). On T1-weighted (TR/TE = 400–600/10–17 msec) images, the tumors were hypointense compared to the liver. The five tumors studied with dynamic MR imaging showed progressive centripetal filling-in after intravenous administration of a gadolinium chelate. On T2-weighted (TR/TE = 2000–2500/80–100 msec) images, all tumors were hyperintense compared to the liver; five were markedly hyperintense and two moderately hyperintense. Vascular encasement, bile duct dilatation within the tumor, and central scar were depicted on MR images in four, three, and two tumors respectively. Conclusion: The typical MR appearance of intrahepatic cholangiocarcinoma is a large well-delineated nonencapsulated tumor associated with intrahepatic venous encasement.     

Dynamic contrast-enhanced MR imaging of fibrolamellar hepatocellular carcinoma

The magnetic resonance (MR) appearance of fibrolamellar hepatocellular carcinoma (FL-HCC) on T1- and T2-weighted and dynamic serial postgadolinium-DTPA images is reported. Both tumors were large (>7 cm in shortest dimension) and had central regions of low signal intensity on T1- and T2-weighted images. Diffuse heterogeneous enhancement of the tumors occurred on immediate postcontrast images. Lesions became more homogeneous in enhancement over time, but lack of enhancement of central portions of the tumor persisted. Although persistent lack of enhancement of the tumor scar on late postcontrast MR images may be characteristic of FL-HCC compared with delayed enhancement in focal nodular hyperplasia, the potential similarities between these tumors is stressed.     

MR imaging of mixed hepatocellular and cholangiocellular carcinoma

Two patients with mixed hepatocellular and cholangiocellular carcinoma underwent partial hepatectomy after magnetic resonance (MR) imaging. Correlation is made with the histopathologic manifestations. In both cases the tumors showed relative low signal intensities on T1-weighted spin-echo (SE) images and high signal intensities on T2-weighted SE images. Dynamic MR imaging showed the enhancement from the periphery of the tumor to the inner area gradually and the enhancement continued into the delayed phase. With both cases fibrosis was marked in the inner area of the tumor compared to the peripheral area. The extent and degree of fibrotic tissue is considered to reflect the enhancement on dynamic MR imaging.     

神经纤维瘤病Ⅰ型累及脊柱脊髓的MR表现

目的：研究神经纤维瘤病Ⅰ型患者的脊柱和脊髓内肿瘤的MRI表现，提高对其认识。方法：回顾性分析15例经临床及病理证实的神经纤维瘤病Ⅰ型患者的脊柱MRI影像资料。结果：MRI显示肿瘤仅位于脊髓2例，髓外硬膜内和硬膜外3例，同时累及髓内和髓外的多发病变10例。肿瘤位于椎旁5例。MRI表现：脊髓、脊神经根局部梭形或结节样增粗，T1WI为等或低信号；T2WI为高信号；增强有明显强化。结论：MRI能很好的显示神经纤维瘤病Ⅰ型患者的脊柱和脊髓内病变的形态、部位和范围，是评价神经纤维瘤病累及脊柱和脊髓多个平面的最佳选择。     

Multilocular cystic renal cell carcinoma presenting as a solid mass: radiologic evaluation

Background: Multilocular cystic renal cell carcinomas (MCRCCs) are a recently described variety of renal cell carcinoma with characteristic pathological and clinical features. We found that the radiologic appearances of MCRCCs of smaller size did not fulfill the previously documented criteria of the MCRCCs. This study was conducted to analyze the radiologic characteristics of MCRCCs of smaller sizes. Methods: The radiologic findings of 13 multilocular cystic renal cell carcinomas of diameter ranging from 10–32 mm (average 22 mm) seen in nine patients were analyzed in correlation with pathologic findings. Results: On US, the tumors were predominantly hyperechoic (11 of 13 tumors) with or without small anechoic areas. Precontrast CT showed the lesions to be either hypodense or hyperdense depending on the presence of hemorrhage. Degree of contrast enhancement was usually slight. The mean increase in CT attenuation was 28 ±19 (mean±standard deviation) at dynamic phase and 12±10 at delayed phase. On MR imaging, signal intensities of the tumors were high both on T1- and T2-weighted images (7 of 9 tumors) due to proteinaceous fluid or hemorrhage. Dynamic enhanced MR imaging revealed irregular contrast enhancement within the tumor (5 of 6 tumors). Angiography failed to reveal neovascularity. Conclusion: Although multiple cysts were seen within the tumors pathologically, MCRCCs of smaller sizes appeared solid on radiologic examinations. However, contrast enhancement or neovascularity was very slight.     

MR imaging of hepatocellular carcinoma

MR imaging is useful in the diagnosis and early detection of HCC. Characteristic findings for overt HCC, a pseudocapsule and an intratumoral mosaic pattern, are better demonstrated on MR imaging than by other imaging modalities such as ultrasound and CT scanning. Signal intensity on T2-weighted images is useful in evaluating the grade of malignancy of hepatocytic nodular lesions. Hyperintensity on T1-weighted MR imaging is almost always seen in precancerous hepatocellular lesions and in about one third of overt HCC tumors, whereas other hepatic tumors show hypointensity on T1-weighted MR imaging. In evaluating tumor vascularity, gadolinium-enhanced dynamic MR imaging is an essential and powerful tool.     

胰岛细胞瘤的影像学表现（附10例分析）

目的胰岛细胞瘤较少见，目前对胰岛细胞瘤的CT表现报道较多，MRI表现报道较少。本研究分析胰岛细胞瘤的CT及MRI表现，着重探讨MRI的诊断价值。方法回顾性分析经手术病理证实的10例胰岛细胞瘤的CT及MRI表现。结果10例胰岛细胞瘤中，8例为功能性胰岛细胞瘤，2例为无功能性胰岛细胞瘤，其中4例为恶性。胰岛素瘤普通CT多表现为等密度，轻度强化，较易漏诊。MRI多表现为T1WI低信号，T2WI高信号，常规增强后轻度强化，动态MRI增强早期可明显强化。功能性胰岛细胞瘤体积多较小，无功能性或恶性胰岛细胞瘤体积多较大。恶性胰岛细胞瘤多伴肝脏或淋巴结转移。结论胰岛细胞瘤的影像学表现具有一定的特征性，MRI较常规CT能提供更多的诊断信息．尤其是动态增强MRI。     

Struma ovarii: MR appearances

Background: Analysis of unenhanced and contrast-enhanced magnetic resonance (MR) images of struma ovarii, a rare benign neoplasm of the ovary, is the aim of this study. Methods: T2-weighted and Gd-DTPA-enhanced T1-weighted MR images of five histologically proven struma ovarii were evaluated retrospectively. Results: In all patients, unenhanced and contrast-enhanced T1-weighted MR images showed complex cystic masses composed of multiple cysts and a solid component, indicating the presence of large and small thyroid follicles. In four patients, the cyst fluid was hypointense on T1-weighted images and hyperintense on T2-weighted images. In one patient, the fluid was hyperintense on T1-weighted images and hypointense on T2-weighted images due to hemorrhage. Conclusion: A complex mass composed of multiple cysts and a solid component, indicating the presence of large and small thyroid follicles, appeared to be a characteristic MR finding of struma ovarii. Received: 11 December 1995/Accepted: 15 December 1995     

Focal nodular hyperplasia of the liver: detection and characterization with plain and dynamic-enhanced MRI

Background: We compared nonenhanced and dynamic gadolinium (Gd)–enhanced magnetic resonance imaging (MRI) appearances of hepatic focal nodular hyperplasia (FNH) as depicted with breath-hold MR sequences and assessed the detectability of the individual MR sequences used. Methods: We retrospectively reviewed 48 consecutive patients with FNH. All patients underwent nonenhanced (T1 fast low-angle shot [FLASH] and T2 half-Fourier acquisition [HASTE]) and dynamic Gd-enhanced (T1 FLASH) MRI between December 1997 and March 2000. Individual MR sequences were analyzed separately for number of lesions, signal intensity features, dynamic enhancement pattern, and the presence and enhancement profile of a central scar. Ninety-five percent confidence intervals of absolute discrepancy were calculated to define differences in lesion detection. Results: Seventy-seven lesions were found in 48 patients. Nonenhanced FLASH imaging depicted 59 (76.6%) lesions in 45 patients. HASTE images showed 55 (71.4%) lesions in 44 patients. On T1- and T2-weighted images, lesions appeared predominantly hypointense (69.5%) and hyperintense (72.7%), respectively. Arterial and portal venous dominant phase Gd-enhanced MRI demonstrated all 77 lesions (100%), most of which showed hypervascular (94.8%), homogeneous (97.4%), and incomplete (except the central scar: 58.4%) enhancement in the arterial phase. Portal venous phase images showed lesion isointensity (50.6%) or moderate hyperintensity (46.8%) with complete enhancement (central scar: 94.8%). A central scar was detected on nonenhanced T1-weighted images (hypointense: 100%), T2-weighted images (hyperintense: 100%), arterial phase (hypointense: 59.7%) and portal venous phase (hyperintense: 71.4%) Gd-enhanced images in 78%, 69.1%, 77.9%, and 75.3% of tumors, respectively. Conclusion: Arterial and portal venous phase Gd-enhanced T1-weighted sequences are superior to nonenhanced images in the detection of FNH. Typical MRI appearances include hypointensity on T1-weighted and hyperintensity on nonenhanced T2-weighted images. Most commonly, FNH shows a homogeneous (without scar) and strong enhancement during the arterial phase, with lesion isointensity or slight hyperintensity during the portal venous phase. Received: 15 May 2001/Revision accepted: 22 August 2001     

Fan-shaped hepatic parenchymal damage after ethanol injection therapy for hepatocellular carcinoma: MRI appearances

Background: T1- and T2-weighted magnetic resonance (MR) images frequently show fan-shaped areas of hypo- or hyperintensity in the hepatic parenchyma adjacent to a treated hepatocellular carcinoma after percutaneous ethanol injection (PEI) therapy. These areas correspond to abnormal contrast enhancement on serial dynamic MR images. The purpose of the present study was to describe the location, appearance, and frequency of these abnormalities because it is important to understand these entities for the correct assessment of therapeutic efficacy. Methods: MR imaging including a multisection dynamic study was performed in 20 consecutive patients with hepatocellular carcinoma treated with PEI therapy. We retrospectively evaluated the presence of fan-shaped hypointensities adjacent to treated tumors in the liver parenchyma on T1-weighted images and hyperintensities on T2-weighted images and corresponding fan-shaped contrast enhancement on both arterial-dominant and delayed-phase dynamic MR images. We review the location, appearance, and frequency of these findings, and we discuss the possible causes on the basis of pathologic examinations. Results: Seven (35%) of the 20 patients showed fan-shaped hyperintense areas adjacent to the treated tumors on T2-weighted images. These areas showed isointensity in five patients and hypointensity in two patients on T1-weighted images. Of these seven patients, one (14%) underwent the MR imaging within 1 month after the completion of PEI therapy, and six (86%) had it 2–9 months after the completion of PEI therapy (mean = 6 months). In all seven patients, fan-shaped hyperperfusion abnormalities corresponding to these areas of hyperintensity on T2-weighted images were seen on both arterial-dominant and delayed-phase dynamic MR images. Pathologically, the coagulative necrosis of the hepatocytes with sinusoidal dilatation and the restoration by the development of fibrous tissue were seen in these fan-shaped areas. Conclusion: The fan-shaped areas of abnormal intensity on T1- and T2-weighted images and contrast enhancement on dynamic MR images seem to be attributable to pathologic changes in the normal liver parenchyma induced by the toxic reaction of ethanol. Awareness of the occurrence of such abnormalities in the peripheral liver parenchyma adjacent to the treated tumor is important for the correct assessment of therapeutic efficacy. RID="ID="<e5>Correspondence to:</e5> T. Fujita Received: 24 June 1997/Accepted after revision: 22 October 1997     

肝脏局灶性结节增生的MRI表现与病理对照分析

目的：分析肝脏局灶性结节增生（FNH）的平扫和动态增强的MRI表现及诊断价值，提高FNH诊断的准确率。方法：回顾性分析15例（16个病灶）经病理证实的FNH的平扫及动态增强MRI表现。结果：16个病灶于T1WI呈略低信号或等信号，T2WI呈略高信号或等信号。增强扫描动脉期呈明显强化，在门脉期及延迟期呈等或略高强化。5个病灶在平扫MRI上显示中央瘢痕，11个病灶在动态增强MRI上显示中央瘢痕，均见延迟强化。结论：平扫和动态增强MRI检查能较全面显示FNH的病理特征和血供特点，明显地提高与其他富血管恶性肿瘤的鉴别诊断能力。     

MR imaging features of uterine adenomyomas

Background

To evaluate the magnetic resonance (MR) imaging features of uterine adenomyoma in comparison with histopathologic findings.

Materials and methods

MR images of seven patients who had surgically proven uterine adenomyoma were retrospectively reviewed by two radiologists in consensus regarding the morphologic appearance, including tumor size, location, margin, presence of concomitant adenomyosis, presence and signal intensity of cavity within tumor, and signal intensity and enhancement pattern of solid portion of tumor. MR imaging findings were correlated with histopathologic findings.

Results

Tumor location was submucosal in three cases, subserosal in two, and mixed mural/subserosal in two. All tumors were well circumscribed on T2-weighted images and contrast-enhanced fat-suppressed T1-weighted images. In six cases, well defined cavities of high signal intensity, which reflected hemorrhagic cavities pathologically, were demonstrated within the tumors on T1-weighted images. Concomitant adenomyosis was observed in five cases. Solid portion of all tumors except hemorrhagic cavities exhibited iso-signal intensity on T1-weighted images, various signal intensity on T2-weighted images, and homogeneous enhancement on contrast-enhanced fat-suppressed T1-weighted images in five cases.

Conclusion

When MR imaging shows a well circumscribed mass with hemorrhagic cavities of high signal intensity on T1-weighted images and concomitant adenomyosis in the uterus, adenomyoma should be considered in the differential diagnosis.     

韧带样纤维瘤病的CT及MRI特征及病理对照

目的回顾性分析韧带样纤维瘤的CT及MRI特征表现及病理基础。方法收集经手术病理证实的韧带样纤维瘤共27例影像学及病理资料,CT检查12例,MRI检查14例,另1例行CT及MRI检查;全部病例均行增强扫描。结果27例共30个病灶,16个病灶发生于腹壁,14个病灶发生于腹壁外。形态：全部病灶均沿肌纤维长轴生长,20个呈梭形或类圆形,10个不规则形;7个边界较清,23个边界不清。与肌肉密度、信号相比：CT上10个病灶呈稍低密度,3个呈等密度,9个渐进性中度强化,4个不均匀性强化;T1WI上9个病灶呈等信号,9个病灶呈稍低信号;T2WI上15个呈高或稍高信号,3个呈混杂信号;STIR上均呈较高信号,15个内部见条片状低信号;增强扫描所有病灶不均匀性渐进性中度强化,其中12个内部条状斑片状的低信号未见明显强化。病理上肿瘤多呈浸润性生长,由纤维母细胞和肌纤维母细胞组成,内部见致密纤维组织及胶原组织,部分见黏液沉积。结论韧带样纤维瘤的CT、MRI表现有一定特征,肿瘤多呈浸润生长,瘤内出现特征性稍低密度或条带状低信号,无液化坏死区,渐进性中度强化。