Hepatic iron deposition on MR imaging in patients with chronic liver disease: correlation with serial serum ferritin concentration

Background: To evaluate the relationship between magnetic resonance (MR) imaging grading of iron deposition and serial serum ferritin concentration in patients with chronic viral liver diseases. Methods: In 80 patients with viral hepatitis and cirrhosis, MR images including T2*-weighted gradient echo images (echo time ≥ 6.5 ms) were reviewed. The grades of parenchymal iron deposition and iron-containing nodules in the liver and spleen and the liver-to-muscle and spleen-to-muscle signal intensity ratios were compared with the most recent, the mean, the lowest, and the highest values from all available serum ferritin levels. Results: The serum ferritin concentration was significantly correlated with the grades of iron deposition in liver and spleen and with the grades of iron-containing nodules seen on MR images (p < 0.05). Liver-to-muscle signal intensity ratio was weakly correlated with the ferritin concentrations. Among categories of ferritin concentration, correlation with MR grades was highest for mean ferritin concentration (r = 0.487, p < 0.001). Conclusion: MR imaging grades of hepatic iron and siderotic nodules correlate with serum ferritin, especially with the mean levels. Received: 9 May 2000/Accepted: 28 June 2000     

Hepatic parenchymal enhancement in the cirrhotic liver: evaluation by triple-phase dynamic MRI

Background: To evaluate the changes of liver parenchymal enhancement in the cirrhotic liver by means of triple-phase dynamic magnetic resonance (MR) imaging. Methods: Triple-phase multisection dynamic MR imaging was performed in 32 patients with liver cirrhosis. The control group consisted of 19 patients without liver cirrhosis. After precontrast images were obtained, arterial phase images were acquired 20 s after the start of intravenous bolus administration of 0.10 mmol/kg of gadopentetate dimeglumine. Portal and delayed phase images were then acquired 1 and 3 min, respectively, after the injection of contrast material. On each phase image, the signal-to-noise ratio (S/N) from the liver parenchyma was measured by operator-defined regions of interest (ROIs). The contrast-enhanced ratio (CER) on each phase was then obtained according to the following formula: [S/N(arterial or portal or delayed phase image) − S/N(precontrast image)]÷ S/N(precontrast image). The portal perfusion index (PPI) also was obtained according to the following formula: [S/N(portal phase image − S/N(arterial phase image)]÷ S/N(arterial phase image). The results were expressed as mean ± SD. Results: The CERs of arterial, portal, and delayed phase images in patients with and without liver cirrhosis were 0.256 ± 0.211, 0.640 ± 0.384, and 0.554 ± 0.318 and 0.132 ± 0.094, 0.404 ± 0.204, and 0.324 ± 0.144, respectively. The CERs were highest in the portal phase and lowest in the arterial phase in patients with and without liver cirrhosis. The CER of the cirrhotic liver was significantly higher than that of the normal liver in every phase (p < 0.05). PPIs with and without liver cirrhosis were 2.90 ± 4.03 and 3.86 ± 3.89, respectively. The PPI with liver cirrhosis was significantly lower than that without liver cirrhosis (p < 0.05). Conclusion: The enhancement of cirrhotic liver parenchyma is greater than that of the normal liver parenchyma at every phase of triple-phase dynamic MR imaging. Received: 17 August 2000/Revision accepted: 7 March 2001     

Significance of hyperattenuating and contrast-enhancing hepatic nodules detected in the cirrhotic liver during arterial phase helical CT in pre–liver transplant patients: radiologic–histopathologic correlation of explanted livers

Background: Hyperattenuating nodules detected by arterial phase helical computed tomography (HCT) in patients with cirrhosis usually are believed to represent hepatocellular carcinomas (HCCs). We correlated HCT morphology of hyperattenuating hepatic nodules detected during arterial phase scans with the histopathology of explanted livers of patients with hepatic cirrhosis undergoing liver transplantation. Methods: Three hundred fifty-four patients had arterial and portal phase HCT performed before subsequent hepatic transplantation. Each patient received 180 mL of contrast by power injection at 5 mL/s. All hyperattenuating nodules detected on arterial phase HCT were assessed for morphology and evidence for contrast enhancement. Explanted livers in all patients were then sectioned at 10-mm intervals, and the histology of the nodules was correlated with the HCT findings. Results: Sixty-one hyperattenuating nodules were detected on the arterial phase HCT in 43 patients: 41 nodules were benign regenerating nodules (RN), three were dysplastic nodules (DP), and 17 were HCCs. Most RN/DP nodules were 5–20 mm in diameter, had distinct margins, were homogeneous, and were isoattenuating on precontrast, portal, and delayed scans. Thirty-six showed positive contrast enhancement and displayed a wide range of attenuation profiles. HCC nodules were 6–50 mm. All showed positive contrast enhancement and displayed a wide range of attenuation profiles. Conclusion: Hyperattenuating nodules seen on arterial phase HCT are likely to be RN/DP nodules. In many cases, it is not possible to distinguish between RN/DP and HCC. Thus, clinical decisions regarding inclusion criteria for transplantation based on CT morphology of liver lesions may be tenuous.     

Focal nodular hyperplasia of the liver: serial MRI with Gd-DOTA,superparamagnetic iron oxide,and Gd-EOB-DTPA

Background: To demonstrate the improved specificity of liver MRI in diagnosis of focal nodular hyperplasia (FNH) using liver specific contrast agents. Methods: In a patient after resected adenosarcoma of the uterus a focal nodular hyperplasia was followed. Serial MRI of the liver was performed using first Gd-DOTA, followed by superparamagnetic iron oxide (SPIO) as well as Gd-EOB-DTPA. Results: During the follow-up of FNH specificity of liver MRI improved using liver specific contrast agents. The central scar as well as the pseudocapsule showed different typical contrast uptake using all three methods. Conclusion: Serial MRI of the liver with Gd-DOTA, SPIO and Gd-EOB-DTPA can exclude a malignant liver lesion. Liver biopsy of FNH can be avoided with increased specificity of MRI for FNH. Received: 15 December 1995/Accepted: 17 January 1996     

Dysplastic nodules of the liver: imaging findings

Background: To verify characteristic features of hepatic dysplastic nodules at different imaging modalities. Methods: Twenty-eight patients with 37 dysplastic nodules of the liver (0.8–3.0 cm) underwent sonography (28 patients), computed tomography (CT; 24 patients), magnetic resonance (MR; 11 patients), and angiography (12 patients). Each nodule was analyzed for echogenicity, attenuation, signal intensity, and vascularity. Results: Echogenicity of nodules was high in 16 (43%), homogeneous in two (6%), and low in 19 (51%) of 37 nodules. Attenuation of nodules was high in one (7%), homogeneous in four (26%), and low in 10 (67%) of 15 nodules on the arterial-phase CT images; homogeneous in five (33%) and low in 10 (67%) of 15 nodules on the portal-phase CT images; and high in four (17%), homogeneous in six (26%), and low in 13 (57%) of 23 nodules on the delayed-phase CT images. Signal intensity of nodules was high in 15 (94%) and homogeneous in one (6%) of 16 nodules on T1-weighted MR images and was homogeneous in seven (44%) and low in nine (56%) of 16 nodules on T2-weighted MR images. Vascularity of nodules was avascular in 14 (88%) and slightly vascular in two (12%) of 16 nodules. Conclusions: Hepatic dysplastic nodules show diverse imaging characteristics with different imaging techniques; however, common imaging findings of hepatic dysplastic nodules are low echo, low attenuation, and high, low, or homogeneous intensity on T1- and T2-weighted MR, and avascularity. Received: 13 May 1998/Accepted: 1 July 1998     

Diffusion-weighted MR imaging with single-shot echo-planar imaging in the upper abdomen: preliminary clinical experience in 61 patients

Background: To determine the potential ability of diffusion-weighted magnetic resonance (MR) imaging with single-shot echo-planar imaging (DW imaging) in the upper abdomen by apparent diffusion coefficient (ADC) and signal:intensity ratio (SIR) measurements. Methods: DW imaging was performed in 61 clinical patients. ADCs in the liver, pancreas, spleen, kidney, and different pathological conditions were calculated. Spleen-to-liver SIR and segmental intensity difference of the liver (SID) were also calculated. Results: The mean ADCs (mm²/s) were 2.28 × 10⁻³± 0.07 in the liver, 1.44 × 10⁻³± 0.05 in the spleen, 1.94 × 10⁻³± 0.19 in the pancreas, and 5.76 × 10⁻³± 0.06 in the kidney. The mean ADC of cirrhotic liver was 1.96 × 10⁻³± 0.62, which was lower than that of normal liver. Other pathologic conditions also showed ADCs different from those of normal tissues. All DW images showed significantly higher spleen-to-liver SIRs and SIDs than did T2-weighted images (p < 0.05). Conclusion: The mean ADCs obtained with DW imaging were different in each upper abdominal organ and with each pathologic condition. DW images showed better soft tissue contrast than did T2-weighted images with regard to SIR and CNR in depicting and characterizing upper abdominal disorders. Received: 24 July 1998/Revision accepted: 2 December 1998     

Pericaval fat collection mimicking an intracaval lesion on CT in patients with chronic liver disease

Background: Localized fat collections, which mimic fat-containing lesions of the inferior vena cava (IVC) on computed tomographic (CT) images, have been reported as rare incidental findings. Our goal was to evaluate the association of this CT finding with chronic liver disease. Methods: Sixty-one patients with chronic liver disease were prospectively studied with contrast-enhanced abdominal CT. The prevalence, attenuation, location, shape, and size of the pericaval fat collections were assessed. Multidirectional reformatted CT images were obtained from helical CT data to identify origins of the pericaval fat collections. Sixty-one patients without chronic liver disease were studied as control subjects. Results: Pericaval fat collections were seen on abdominal CT in 16 (26.2%) of the 61 patients. On the reformatted images, the fat collections were contiguous to the fat tissue around the subdiaphragmatic esophagus in all 16 patients. The fat collections were located at the posterior aspect of the IVC in 12 patients. In the control group, pericaval fat collection mimicking an intracaval lesion was not seen. Conclusion: In patients with chronic liver disease, pericaval fat collections are not rare CT findings and their characteristic location is considered to be posterior to the IVC. It is important not to misinterpret such CT findings as abnormalities of the IVC, such as thrombus or tumors. Received: 18 October 2000/Accepted: 15 November 2000     

Ultrasonographic changes of early liver cirrhosis in chronic hepatitis B: A longitudinal study

Ultrasonography of prospectively followed chronic hepatitis B patients who developed liver cirrhosis were reevaluated in order to identify the ultrasonographic changes of early cirrhosis. Ultrasonographic features of 29 patients before and after cirrhosis were as follows: portal vein diameter—1.20 cm/1.29 cm (NS); cirrhosis score—5.69/7.52 (p < 0.01); spleen size index—21.99 cm²/25.84 cm² (NS). The result suggests that ultrasonographic diagnosis of early cirrhosis is not easy on a single occasion; however, the score system method is helpful in longitudinal follow-up chronic hepatitis patients. A careful comparison of hepatic parenchymal and surface changes are mandatory. © 1993 John Wiley & Sons, Inc.     

Peribiliary cysts in cirrhotic liver: observation on computed tomography

Background: To analyze the frequency and number of suspected peribiliary cysts in cirrhotic liver on computed tomography (CT). Methods: Three hundred forty-six cases with clinically diagnosed liver cirrhosis (LC) and 307 cases with clinically diagnosed non-LC were subjected to the study. The frequency and number of suspected peribiliary cysts on CT were compared between the two groups. The existence of peribiliary cysts was suggested when a cyst was observed around the second- to fourth-order branches of the intrahepatic portal vein. Results: Peribiliary cysts were suggested on CT in 31 of 346 cirrhotic livers (9.0%) and 10 of 307 noncirrhotic livers (3.3%). This difference in the frequency of peribiliary cysts was statistically significant (χ², p < 0.01). Multiple peribiliary cysts were seen in 71% of cirrhotic patients with peribiliary cyst. The size of peribiliary cysts was smaller than 1.5 cm in diameter. Conclusion: Peribiliary cyst is radiologically observed more frequently in cirrhotic liver than in noncirrhotic liver and is occasionally multiple. Received: 1 November 1994/Accepted after: 24 February 1995     

Altered flow dynamics of intravascular contrast material to the liver in superior vena cava syndrome: CT findings

Background: To evaluate the findings of altered flow dynamics in the livers of patients with obstruction of superior vena cava (SVC) on helical computed tomography (CT). Methods: In six patients (age range = 28–80 years) with SVC obstruction, CT findings were retrospectively reviewed to identify the abnormal enhancement patterns of the liver and the relation with the extrahepatic collateral vessels and hepatic vessels. Results: Abnormal hepatic enhancement was observed in the following four (A–D) portions: (A) anterior portion of segment IV (n = 5), (B) subdiaphragmatic portion of the liver (n = 4), (C) posterior portion of the right lobe (bare area; n = 1), and (D) lateral segment of the left lobe (n = 2). Two major collateral pathways to the liver were demonstrated as follows: A and D → from the umbilical vein to the left portal vein, and B and C → from the subcapsular vein to the bare area of the liver or to the hepatic veins. On helical CT, these collateral pathways were also clearly visualized. Conclusion: When these abnormal enhancements of the liver on CT are recognized within the liver, these findings indicate diversion of contrast material into collateral pathways to the liver with SVC obstruction. Received: 31 March 1999/Revision accepted: 25 June 1999     

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.     

Hepatic falciform artery: angiographic observations and significance

Background: The purpose of this study was to assess the angiographic incidence and appearance of the hepatic falciform artery (HFA) and discuss its clinical significance. Methods: Hepatic angiograms of 53 patients obtained with digital subtraction angiography were prospectively evaluated with regard to incidence, anatomic features, and flow speed of the HFA. We analyzed whether the background of chronic liver disease affected the incidence of the HFA. Transcatheter arterial chemoinfusion or chemoembolization for liver tumors was performed in 33 patients. We noted the occurrence of supraumbilical skin complications. Results: The HFA was observed in 13 (24.5%) of 53 patients on celiac or common hepatic angiograms. The blood flow of the HFA was slower than that of the peripheral hepatic arteries in all patients. No significant difference in the incidence of HFA between the 34 patients with chronic liver disease and the 19 patients with normal livers was found. One treated patient with an HFA and a history of gastrectomy developed a supraumbilical red skin rash. Conclusion: The angiographic incidence of the HFA is more common than previously reported. The delayed and persistent opacification of the HFA on hepatic angiograms caused by its slow blood flow is considered the key to its identification. Received: 18 November 2000/Accepted: 27 December 2000     

脂肪肝MRI同反相位定量测量与CT值相关分析

目的：分析脂肪肝MRI同反相位定量测量与CT值相关性,并评价MRI同反相位定量测量判断脂肪肝的价值。方法：回顾性分析86例临床疑诊脂肪肝而行CT、MRI检查病例,测量相应的CT值及同反相位上的MR信号,计算3个CT值比及4个信号指数。使用Pearson相关分析3个CT值比与4个信号指数间的相关性,并以CT值肝/脾≤1作为脂肪肝标准,计算不同阈值下信号指数判断脂肪肝的敏感性、特异性和准确性。结果：各CT值比与各信号指数间均呈明显负相关（r=-0.823～-0.917）,其中以CT值肝/脾与信号指数1之间的相关性最高（r=-0.917,P=0.000）。以CT值肝/脾≤1作为脂肪肝标准,判断脂肪肝时,信号指数1、信号指数4均以阈值≥0.1最佳,准确性分别为86.05%和89.53%。结论：CT值肝/脾与MRI同反相位定量测量有很好的相关性,两者都能作为脂肪肝定量评价的手段,并且能互为补充。以信号指数1或信号指数4≥0.1的标准诊断脂肪肝是合适的。     

Hepatic MR imaging: comparison of RARE derived sequences with conventional sequences for detection and characterization of focal liver lesions

Background: We compared two T2-weighted turbo spin echo (TSE) sequences with a T2-weighted conventional SE (CSE) sequence to determine whether sequences derived from rapid acquisition with relaxation enhancement such as TSE could replace CSE for the detection and subsequent characterization of focal liver lesions. Methods: A total of 55 consecutive patients with 107 liver lesions underwent magnetic resonance imaging examinations at 1.5 Tesla, with a constant imaging protocol. TSE pulse sequences were acquired with eight echo trains (repetition time [TR], 4718 ms; echo time [TE], 90 ms; acquisition time [TA], 4.03 min; and a symmetric k-space ordering scheme) and 11 echo trains (TR, 4200 ms; TE, 140 ms; TA, 4.40 min; and an asymmetric k-space ordering scheme) and compared with CSE (TR, 2300 ms; TE, 45/90 ms; TA, 9.53 min). Images were analyzed qualitatively by scoring image quality and artifacts and counting focal liver lesions by independent reading with consensus obtained for discrepancies. Quantitative analysis was performed by measuring signal-to-noise (S/N), contrast-to-noise (C/N), and tumor–liver signal intensity (T/L) ratios. Results: T2-weighted TSE sequences provided better subjective image quality and reduced artifacts as compared with the T2-weighted CSE sequence. CSE and TSE sequences exhibited no statistically significant differences in liver S/N, lesion–liver C/N (CSE TE, 90 ms: 18.6 ± 14.0; TSE TE, 90 ms: 16.5 ± 12.9) and the detectability of focal liver lesions. Heavily T2-weighted TSE with a TE of 140 ms allowed correct characterization of focal liver lesions based on a T/L ratio of 3.0 in 84% of patients. Conclusions: T2-weighted TSE sequences are as suited as CSE for the detection (TE, 90 ms), and appear to be superior for the characterization (TE, 140 ms), of focal hepatic lesions. Whether a single sequence, such as a double-echo TSE or a single-echo TSE sequence with a TE between 110 and 120 ms, might perform both functions as well or better than CSE is unknown. However, because of time savings, TSE eventually may be preferred over CSE. Received: 13 December 1994/Accepted after revision: 31 March 1995     

Struma ovarii: appearance on MR images

Background: The purpose of this multi-institutional study was to examine the appearance of struma ovarii on magnetic resonance (MR) images. Methods: MR images of 12 patients with histologically proven struma ovarii were retrospectively reviewed. All patients underwent T1-weighted and T2-weighted imaging. Contrast-enhanced T1-weighted images with Gd-DTPA were available in 10 patients. The following determinations were made: tumor morphology, signal intensities, contrast-enhancement effects of solid components with Gd-DTPA, and comparison of MR images with resected specimens. Results: All 12 patients had both cystic and solid components, with a multilobulated surface and thickened septa. Signal intensities on T1-weighted images were mainly low, partly intermediate to high, or high, and those on T2-weighted images were mainly high, with different signal intensities. Contrast-enhancement effects were marked or moderate. The contents that showed low signal intensities on T1-weighted images and signal voids or low signal intensities on T2-weighted images were viscid gelatinous materials. Conclusions: A multicystic tumor with a solid component, a multilobulated surface, and signal intensities that indicate the presence of viscid gelatinous materials appear to be a characteristic MR finding of struma ovarii. Received: 10 April 1997/Accepted after revision: 7 July 1997     

SPIO-enhanced MR imaging of focal fatty liver lesions

BACKGROUND: The purpose of this study was to assess the features of focal fatty liver lesions with superparamagnetic iron oxides (SPIO) on magnetic resonance (MR) images. METHODS: We retrospectively studied five patients with six histologically proven focal fatty liver lesions who had been examined by MR with use of SPIO. The features of the focal fatty liver lesions on two T2-weighted post-SPIO-enhanced MR images, T2*-weighted fast low-angle shot (FLASH) sequences, and T2-weighted turbo-spin echo (TSE) sequences were analyzed, and the percentages of signal intensity loss of the lesions and normal liver parenchyma were calculated. RESULTS: All the fatty liver lesions exhibited different degrees of SPIO uptake, which were presented by a distinct loss of signal intensity on both post-SPIO-enhanced T2-weighted sequences. The percentage of signal intensity loss of the lesions on SPIO-enhanced images was higher than that of normal liver parenchyma in all the cases. CONCLUSION: Focal fatty liver lesions exhibit a high uptake of SPIO. The uptake is higher than that of the normal liver.     

Characterization of solid liver lesions with color and pulsed Doppler imaging

Background: To assess the usefulness of color Doppler and duplex sonography in the characterization of solid liver lesions. Methods: We performed color Doppler and duplex sonography on 106 solid hepatic lesions. With color Doppler, we evaluated the aspect and distribution of tumoral vessels. The pulsed Doppler parameters considered were only those showing the highest systolic peak velocity values. Results: Intratumoral color and pulsed Doppler signals were obtained in 81% (59/73) of malignant tumors (p < 0.0001) but only in 18% (6/33) of benign tumors. Ninety-six percent (45/47) of the lesions with arterial intratumoral and peritumoral signals were malignant, whereas 4% were benign (p < 0.0001). Only eight (11%) malignant lesions had intratumoral venous signal vis-a-vis 23 (70%) benign. Twelve cases showing intratumoral venous Doppler signal as a single finding were benign. No statistically significant differences were observed in the quantitative parameters recorded by pulsed Doppler (Student t test, p < 0.05), there having been a clear overlapping in the values obtained in benign and malignant lesions. Conclusions: (a) The type of signal (arterial or venous) and its distribution detected by color and pulsed Doppler is more helpful than the assessment of the spectral quantitative parameters obtained by pulsed Doppler. (b) The presence of intratumoral venous flow remarkably suggests benignancy. (c) The presence of both intra- and peritumoral arterial flow in the same lesion strongly suggests malignancy. Received: 3 January 1997/Revision accepted: 17 December 1997     

Transjugular liver biopsy: modified Ross transseptal needle versus Quick-core biopsy needle

Background: We evaluated the differences in sample adequacy and safety between a transseptal needle and Quick-core biopsy needle for transjugular liver biopsy. Methods: Eighteen consecutive patients who had a bleeding diatheses and/or ascites underwent transjugular liver biopsy using a transseptal needle (11 patients) and Quick-core biopsy needle (seven patients). The length of the specimens was measured before fixation. A pathologist reviewed histologic slides for sample adequacy and pathologic diagnoses. Clinical records were reviewed for complication. Results: In all patients, liver biopsy was successful. A total of 45 specimens were obtained, with an average of 2.5 passes per patient. The length of specimen was significantly longer with the Quick-core biopsy needle than with the transseptal needle (p < 0.05). Biopsied tissue was fragmented in 17 of 25 specimens with the transseptal needle but not fragmented in any specimen with the Quick-core biopsy needle. All specimens were determined to be adequate except one with the transseptal needle. There was no early or delayed complication in any patient. Conclusion: Transjugular liver biopsy is a safe and effective procedure without any significant difference in complication and adequacy when using a transseptal needle or Quick-core biopsy needle. Larger specimens can be obtained without tissue fragmentation with the Quick-core biopsy needle. Received: 30 August 1999/Revision accepted: 26 January 2000     

Portal hypertension in children and young adults: sonographic and color Doppler findings

Portal hypertension is a relatively uncommon pathologic condition in children and young adults in contrast with older adults. The aim of this study is to evaluate the utility of sonography and color Doppler sonography in the diagnosis of portal hypertension in children and young patients and to evaluate the sonographic pattern of each disease. We reviewed 25 such patients who were younger than 30 years old and obtained the following sonographic findings: (1) liver cirrhosis: (a) multiple intrahepatic venovenous shunts in patients with primary Budd-Chiari syndrome and (b) intrahepatic vascular narrowing and nodular coarse parenchymal texture, with multiple very-high-echo spots along the portal vein in patients with Wilson disease; (2) congenital hepatic fibrosis: marked and developed collaterals, wide periportal echogenic band, and a heterogeneous parenchymal texture comprised of multiple high echoes but without portal thrombus; and (3) extrahepatic portal thrombosis: invisible portal lumen except as an echogenic band. Sonography and color Doppler sonography are very useful in diagnosing these portal hypertensive diseases. However, there are no specific sonographic findings, and the role of sonography is limited to follow-up observation of associated secondary hepatobiliary changes in patients with congenital biliary atresia. Received: 1 May 1995/Accepted: 24 June 1995     

Well-differentiated hepatocellular carcinoma: findings of US, CT, and MR imaging

Background: To elucidate the imaging characteristics of well-differentiated hepatocellular carcinomas (HCCs) on ultrasonography (US), computed tomography (CT), and magnetic resonance (MR) imaging. Methods: Ultrasonograms, CTs, and MR images of 18 histopathologically proven well-differentiated HCCs in 15 patients were reviewed. The findings of these images were correlated with histopathologic findings. Results: On US, seven tumors were depicted as a hyperechoic area and eight as a hypoechoic area. Three tumors were not visualized. On precontrast CT, four tumors were depicted as a low-density area, but 14 were not visualized. On conventional contrast-enhanced CT, 12 tumors were depicted as a low-density area but six were not visualized. On T1-weighted MR images, 10 tumors had high signal intensity and two had low signal intensity. Six tumors were not visualized. On T2-weighted MR images, five tumors had high signal intensity and two had low signal intensity. Eleven tumors were not visualized. Tumors with fatty change and/or clear cell formation were frequently hyperechoic on US and hyperintense on T1-weighted MR images. Conclusions: Well-differentiated HCCs show different findings on US, CT, and MR imaging. Therefore, reliable diagnosis of well-differentiated HCCs by these imaging techniques may be difficult. Received: 29 April 1998/Revision accepted: 15 July 1998