MR imaging of hepatocellular carcinoma at 1.5 Tesla

The authors investigated the magnetic resonance appearance of hepatocellular carcinoma using a 1.5-Tesla magnet. Twenty-four patients with pathologically proven hepatocellular carcinoma had magnetic resonance imaging (MRI) studies, which were retrospectively reviewed. All patients were imaged with at least two of the following techniques: (1) T1-weighted (T1W), (2) T1-weighted with Gd-DTPA enhancement (T1W-E), (3) T2-weighted (T2W), (4) proton density (PD), and (5) gradient-recalled echoes (GRE). T1W images were equal to T2W images for tumor detection using a grading system. T1W images were slightly better than T2W images for the total number of lesions detected. The other pulsing techniques (PD, T1W-E, and GRE) detected fewer lesions. Eight cases of hepatocellular carcinoma (33%) had nonhomogeneous increased signal intensity on both T1W and T2W images. The authors conclude that T1W images are equal to T2W images for detection of hepatocellular carcinoma. The authors also conclude that 33% of hepatocellular carcinomas have an imaging pattern with increased signal intensity on both T1W and T2W images. This pattern is atypical for most other hepatic masses and hence can be used to suggest the mass is hepatocellular carcinoma.     

MR imaging in intracystic hemorrhage of simple hepatic cysts

Intracystic hemorrhage of simple hepatic cysts is one of the most frequent complications. Ul-trasonography (US) and computed tomography (CT) may show abnormal findings and mimic other diseases. We describe magnetic resonance (MR) imaging in four patients with intracystic hemorrhage confirmed by surgery or percutaneous aspiration. In all cases the lesions were hyperintense on both T1- and T2-weighted sequences. In three of the four cases the signal was heterogeneous on T1-weighted sequences. Two cases of a thickened wall and one case of a fluid-fluid level were also observed. We suggest that MR imaging may be helpful to differentiate intracystic hemorrhage from other cystic lesions by showing high signal on T1- and T2-weighted sequences.     

Hepatic mesenchymal sarcoma: MRI findings

Hepatic undifferentiated mesenchymal sarcoma is a rare pediatric malignant neoplasm. We present three children, aged 7, 8, and 12 years, with this tumor. Clinical presentation was abdominal pain, palpable mass, asthenia, anorexia, and weight loss. One had jaundice. All three lesions were detected on ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI). MRI localized the lesions more accurately than the other methods, with good resectability correlation. On MRI, these tumors were markedly hyperintense on long TR/TE spin-echo (SE) and short-time inversion recovery (STIR) sequences. This was due to the cystic areas with myxoid material and necrosis. The internal septations were hypointense on these sequences. On short TR/TE SE sequences the lesions presented a fibrous pseudocapsule (two cases), and internal hyperintense areas representing hemorrhage (two cases). MRI also detected vascular invasion (one case), biliary obstruction (one case), and biliar adenopathies (one case). The combination of hemorrhage (hyperintense on short TR/TE SE) and cystic or myxoid components (markedly hyperintense on long TR/TE SE and STIR sequences) is common in this tumor.     

Capsule and mosaic pattern of hepatocellular carcinoma: Correlation between CT and MR imaging

Computed tomography (CT) was compared with magnetic resonance (MR) imaging in depicting the capsule and the mosaic pattern of hepatocellular carcinoma in 34 patients. The kappa statistic was used to compare results from both modalities. For the detection of the capsule, there was a substantial agreement beyond chance between late enhanced CT (more than 5 min after dynamic CT) and MR imaging (kappa=0.76). Late enhanced CT and MR imaging had almost perfect agreement for the demonstration of the mosaic pattern (kappa=0.85). These agreements were better than the agreements between unenhanced CT and MR imaging or between early enhanced CT and MR imaging. These results suggest that late enhanced CT compares favorably with MR imaging in depicting the capsule and the mosaic pattern of hepatocellular carcinoma.     

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.     

Accumulation of iron oxide particles around liver metastases during MR imaging

The histologic nature of the bright ring (peritumoral edema) around some liver metastases on T2-weighted magnetic resonance (MR) images is controversial. In the case reported, particles of the iron oxide contrast agent AMI-25 are retained in the peritumoral zone of a colon cancer metastasis, causing the bright ring to disappear. The location of iron particles in resected specimens could be used systematically to study peritumoral edema.     

MR of the kidneys,liver, and spleen in paroxysmal nocturnal hemoglobinuria

The magnetic resonance (MR) findings in the liver, kidneys, and spleen in eight patients with paroxysmal nocturnal hemoglobinuria (PNH) were retrospectively reviewed to determine whether characteristic features could be demonstrated. Eight patients underwent abdominal MR examinations by gradient echo sequences (seven patients), spin-echo sequences (seven patients), and inversion recovery (one patient). Signal intensities of the kidneys, liver, and spleen were visually evaluated. Autopsy and liver biopsy correlation were available in one case each. Renal signal intensity was decreased in all eight patients by either gradient-echo or T2-weighted sequences and in the single inversion recovery sequence. Hepatic signal intensity was decreased in three of eight patients on spin- and gradient-echo images. Splenic signal intensity was decreased in three of eight patients on spin- and gradient-echo images, and in two of these was manifest as focal low signal spots (Gamna-Gandy bodies). While the signal intensity in the renal cortex is typically decreased in patients with PNH, signal intensities in the liver and spleen are variable. Low signal intensity in the kidneys is due to hemosiderin deposition resulting from intravascular hemolysis, whereas low signal intensity in the liver or spleen may be due to either transfusion siderosis, or as a consequence of hepatic or portal venous thrombosis.     

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.     

Primary malignant fibrous histiocytoma of the liver: imaging features of five surgically confirmed cases

Background: The purpose of the present study was to describe the various imaging features of primary malignant fibrous histiocytoma (MFH) of the liver, a rare tumor of mesenchymal origin. Methods: Sonography (n= 5), computed tomography (CT; n= 5), magnetic resonance (MR) imaging (n= 2), and hepatic arteriography (n= 3) in five patients who underwent partial hepatectomy for tumor resection were retrospectively reviewed and correlated with pathologic findings. Results: All tumors were clearly demarcated from surrounding hepatic parenchyma in sectional imaging with (n= 2) or without (n= 3) a fibrous capsule, which was pathologically verified. Internal architecture of abundant fibrosis, myxoid degeneration, and/or hemorrhagic necrosis reflected the sonographic, CT and MR imaging findings. Marginal tumor staining without definite tumor vasculature was the main feature of hepatic arteriography. There was no intratumoral calcification. All three tumors involving the right lobe of the liver invaded the right hemidiaphragm. Conclusion: Although there were no unique findings of primary hepatic MFH, a combined interpretation of various imaging modalities may elucidate the malignant nature of the tumor. Received: 20 May 1998/Accepted after revision: 1 July 1998     

MR imaging in hydatid disease of the liver

We describe the appearance on MR of hydatid disease of the liver in 2 patients. The lesions were well demonstrated using spin-echo pulse sequences, and could be easily seen with either T₁ or T₂ weighting; however, maximum information was obtained using both. In these 2 cases, a thin, low signal boundary was noted around the cysts; this finding may prove useful in differential diagnosis.     

Noninvasive imaging of unusual regenerating nodules in the cirrhotic liver

Despite the common occurrence of regenerating liver nodules, little has been written regarding their ultrasound or computed tomographic appearance. In the great majority of cases, they have an echo texture and CT number identical to surrounding hepatic parenchyma. Exceptionally, as in the 2 cases described, they can mimic a malignant neoplasm. Because radionuclide imaging almost always demonstrates uptake over a regenerating nodule, this modality should be used in suspicious cases in conjunction with either ultrasound or computed tomography in order to exclude a malignancy.     

MR横向弛豫时间成像鉴别诊断腮腺良恶性肿瘤

目的 评价横向弛豫时间成像（T2 mapping）鉴别诊断腮腺良恶性肿瘤的价值。方法 回顾性分析73例接受T2 mapping检查并经手术病理证实的腮腺肿瘤患者,其中49例为良性肿瘤（良性组）,包括29例多形性腺瘤（多形性腺瘤亚组）、17例沃辛瘤（沃辛瘤亚组）及2例基底细胞腺瘤和1例神经纤维瘤,24例为恶性肿瘤（恶性组）;测量并比较组/亚组间T2值差异,采用受试者工作特征（ROC）曲线,计算曲线下面积（AUC）,评价T2值鉴别诊断腮腺肿瘤的价值。结果 良恶性肿瘤T2值差异有统计学意义（t''=3.24,P<0.01）,T2值鉴别腮腺良、恶性肿瘤的AUC为0.69,其诊断敏感度为64.69%,特异度为85.72%。多形性腺瘤亚组、沃辛瘤亚组与恶性组间T2值差异有统计学意义（F=18.49,P<0.01）,两两比较示Warthin瘤亚组与恶性组差异无统计学意义（P=0.18）,其余组/亚组间差异均有统计学意义（P均<0.05）。T2值鉴别多形性腺瘤与恶性肿瘤的AUC为0.83,敏感度为79.63%,特异度为94.31%;鉴别沃辛瘤与恶性肿瘤的AUC为0.91,敏感度为93.28%,特异度为89.84%。结论 T2 mapping对鉴别诊断腮腺良、恶性肿瘤,多形性腺瘤与沃辛瘤和多形性腺瘤与恶性肿瘤具有一定价值。     

MR findings of hepatic cavernous hemangioma after intraarterial infusion of iodized oil

Magnetic resonance (MR) imaging was performed on five tumors of three patients who had hepatic hemangiomas. Four tumors were given an intraarterial infusion of 3–8 ml of iodized oil, while one tumor was not. MR images were obtained at 2.0 or 0.5 T. A single spin echo sequence with TE of 30 ms and TR of 500 ms and a double echo sequence with TEs of 60 and 150 ms and TR of 2000 ms, were used to produce relatively T1-, T2-weighted, and heavily T2-weighted images, respectively. Follow-up MR imaging was done 1–5 months after infusion of iodized oil. On relatively T1 weighted images, hemangiomas showed iso or hypointensity. On T2-weighted images, all tumors showed hyperintensity. However, on heavily T2-weighted images, tumors with iodized oil showed heterogeneous, slight hyperintensity, while tumors without iodized oil showed characteristic appearance of marked hyperintensity in hemangiomas. In hepatic cavernous hemangiomas with intraarterial infusion of iodized oil, familiarity with this unusual MR intensity of tumors on heavily T2-weighted images is useful to avoid the incorrect diagnosis and to reduce the frequency of inappropriate hepatic resection.     

Percutaneous biopsy of liver tumors with color Doppler US guidance

Background: Percutaneous liver biopsy is a well-established procedure. Aim of this study was to investigate the usefulness of color Doppler ultrasound (US) for guiding percutaneous biopsy of liver tumors in patients at high risk of bleeding. Methods: Forty-seven patients with severe, uncorrectable coagulopathy (platelet count <50 × 10⁹/L and/or prothrombin time ratio [normal/patient] <50%) were submitted to percutaneous biopsy of focal liver lesions using a 21 G cutting needle. The procedure was guided by color Doppler US, avoiding the needle cross into any liver or tumor vessel. Results: Biopsy material was adequate for pathological reading in 46/47 cases (97.9%). No major post-biopsy complication was observed. In particular, no case of hemoperitoneum was detected on US examinations performed 2 hours after biopsy. Minor complications (including one subcapsular hematoma) occurred in 4 patients (8.5%). Conclusions: Color Doppler US can safely guide percutaneous liver biopsy in patients at high-risk of bleeding.     

MR imaging of adrenal lymphoma

A case of lymphoma of the adrenal glands is presented. Both computed tomography (CT) and magnetic resonance imaging (MRI) demonstrated large bilateral adrenal masses with no other associated abdominal abnormalities. MR was better able to demonstrate inferior vena caval patency than CT, and effectively exclude pheochromocytoma as a differential diagnostic consideration due to signal characteristics of the masses.     

肝恶性肿瘤的超声造影定量分析

目的 探讨肝恶性肿瘤超声造影（CEUS）的时间-强度曲线（TIC）形态和声学定量参数变化特征。方法 应用反向脉冲谐波显像（PIH）技术对48例肝恶性肿瘤患者行实时CEUS检查，以声学定量软件绘制病灶的TIC，分析TIC形态和定量参数变化特征。结果 48例肝恶性肿瘤中，16例原发性肝癌（HCC）、23例肝转移癌（metastasis livercancer，MLC）TIC形态呈快上快下型，4例小HCC、5例MLC呈快上慢下型；HCC中，小HCC降支减半时间迟于非小肝癌（P＜0．01）；MLC降支减半时间早于HCC（P＜0．05）；20s增强强度比较，乏血供MLC低于HCC及富血供MLC（P＜0．01），后二者之间差异无统计学意义。结论 CEUS的TIC形态和定量参数变化特征对肝恶性肿瘤的诊断及鉴别有重要价值。     

三维超声及彩色多普勒成像对肝脏良恶性肿瘤的鉴别诊断

目的探讨三维超声及彩色多普勒成像对肝脏良恶性肿瘤鉴别诊断的价值.方法采用Aloka SSD-5500超声仪及TomTec三维成像系统,对37例肝脏恶性肿瘤及36例良性肿瘤患者行三维超声成像,观察并比较两组肿瘤内部血流分布、有无穿支血流及其血流信号容积与肿瘤体积比(Ⅵ).结果肝脏良恶性肿瘤的外周血流检出率分别为88.89%(32/36)、78.83%(29/37),两组间比较差异无统计学意义(P=0.343);良恶性肿瘤的中心血流显示率分别为33.33%(12/36)、94.59%(35/37),穿支血流的检出率分别为5.56%(2/36)、62.16%(23/37),Ⅵ值分别为(4.56±0.92)、(18.98±1.87),两组间比较差异有非常显著性(P＜0.01).结论三维超声及彩色多普勒成像为肝脏良恶性肿瘤的形态、血流分布及三维血流参数方面提供了更多的诊断信息,对鉴别诊断有一定的价值.     

Liver lesion detection: Comparison between excitation-spoiling fat suppression and regular spin-echo at 1.5T

The role of excitation-spoiling fat suppression (fatsat) imaging in the detection of liver lesions was assessed comparing short TR/TE and long TR/ TE spin-echo (SE) sequences with and without excitation-spoiling fat suppression in 25 patients at 1.5T. The study included patients with liver metastases (n = 21), primary liver cancer (n=3), and hepatic adenoma (n=1). Liver lesion detection and lesionliver signal-to-noise ratios (SNR) were determined for the various imaging sequences in a prospective fashion. Liver lesion-liver SNR were highest for long TR/TE (2000-2500/70-80) fatsat images (12.7±4.8) compared to long TR/TE regular SE (2000-2500/70-80) images (8.8±5.6) [(p = ns) (not significant)], short TR/TE (200-400/15-20) fatsat images (-6.2±4.8) (p=0.05), and short TR/TE regular SE images (-4.9±3.2) (p<0.01). Lesion detection was greatest for long TR/TE fatsat (86) followed by long TR/TE regular SE (78) (p=0.05), short TR/TE fatsat (65) (p<0.01), and short TR/TE regular SE (60) (p<0.01). The results of this study suggest that excitation-spoiling fat suppression may improve liver lesion detection and conspicuity.     

超声造影在诊断肝脏良恶性肿瘤中的应用

目的 探讨良恶性肝肿瘤的超声造影增强时相及回声变化规律。方法 对31例共59个肝肿瘤病灶在超声造影后，观察肿瘤病灶在造影增强后各时相图像特点，对比分析良恶性肝肿瘤造影增强的始增时间、峰值时间及减退时间，并对造影前后及增强CT检测的病灶数目、大小及边界清晰度进行比较分析。结果 17个肝细胞肝癌病灶中13个表现为典型“快进快退”，2个表现为“同进快退”，另2个表现为“快进慢退”，后经病理证实为高分化型肝癌。36个转移性肝癌病灶分为少血供转移癌组21个，表现为动脉相呈低回声环形增强，门脉相及延迟相呈低回声；多血管转移癌组15个，表现为动脉相呈完全高回声增强，门脉相及延迟相呈低回声。6个肝血管瘤中5个表现为向心性环形持续缓慢充填，另一例直径9mm的小血管瘤表现为完全快速向心充填。肝血管瘤造影增强的始增时间、峰值时间及减退时间均长于肝细胞肝癌及转移性肝癌（P〈0．05）。造影后所测肿块直径大于常规超声和增强CT，所检出肿块数目多于常规超声和增强CT，造影前13个肿块边界显示不清晰，造影后显示清晰。结论 超声造影在肝肿瘤的定性诊断中有重要价值。     

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.