Hepatic Cavernous Hemangiomas: Relationship between Speed of Intratumoral Enhancement during Dynamic MRI and Apparent Diffusion Coefficient on Diffusion-Weighted Imaging

OBJECTIVE: To investigate the relationships between the apparent diffusion coefficients (ADCs) on diffusion-weighted imaging (DWI) and the speed of contrast-enhancement in hepatic hemangiomas. MATERIALS AND METHODS: Sixty-nine hepatic hemangiomas (> or = 1 cm) were evaluated with DWI, by using multiple b values (b = 50, 400, 800 s/mm2), followed by a gadolinium-enhanced dynamic MRI. The lesions were classified into three groups, according to the speed of contrast-enhancement on the portal phase. ADCs were measured on the ADC map automatically, and were calculated by using the two different b values (mADC50-400 with b values = 50 and 400; mADC400-800 with b values = 400 and 800 s/mm2). RESULTS: The mean ADCs (x 10-3 mm2/s) were significantly higher in the rapid group (1.9 +/- 0.44) than in the intermediate (1.7 +/- 0.35, p = 0.046) or the slow groups (1.4 +/- 0.34, p = 0.002). There were significant differences between the rapid and the slow groups in mADC50-400 (2.12 vs. 1.48; p = 0.008) and mADC400-800 (1.68 vs. 1.22, p = 0.010), and between the rapid and the intermediate groups in mADC50-400 (2.12 vs. 1.79, p = 0.049). Comparing mADC50-400 with mADC400-800, there was a significant difference only in the rapid group (p = 0.001). CONCLUSION: Higher ADCs of rapidly-enhancing hemangiomas may be related to richer intralesional vascular perfusion. Also, the restricted diffusion may be attributed to the difference of structural characteristics of hemangioma.

Small Malignant Hepatic Tumor Detection in Gadolinium- and Ferucarbotran-Enhanced Magnetic Resonance Imaging: does Combining Ferucarbotran-Enhanced T2*-Weighted Gradient Echo and T2-Weighted Turbo Spin Echo Images have Additive Efficacy?

OBJECTIVE: To determine if a combination of ferucarbotran-enhanced T2*weighted-gradient echo (T2*W-GRE) and T2-weighted turbo spin echo (T2W-TSE) images in gadolinium- and ferucarbotran-enhanced MRI has additive efficacy compared to each image alone for detecting small (< or = 2.0 cm) hepatocellular carcinoma (HCC) lesions in a group of cirrhotic patients and metastases in a group of non-cirrhotic patients. MATERIALS AND METHODS: Two readers retrospectively analyzed gadolinium- and ferucarbotran-enhanced T2*W-GRE, T2W-TSE, and combined T2*W-GRE/T2W-TSE images of 119 patients with 157 HCCs and 32 patients with 98 metastases. The diagnostic accuracy and sensitivity for each image set and the combined set were evaluated using the alternative-free response receiver operating characteristic method. RESULTS: The mean area under the curve value of the combined set (0.966) tended to be better than that for each individual image set (T2W-TSE [0.910], T2*W-GRE [0.892]). Sensitivities in the combined set were higher than those in each individual image set for detecting HCC (mean, 93.0% versus 81.6% and 86.7%, respectively, p < 0.01). Sensitivities in the combined set and the T2W-TSE set were the same for detecting metastases, and both were higher than the sensitivity seen in the T2*W-GRE set (mean, 97.5% versus 85.2 %, p < 0.01). CONCLUSION: Combining ferucarbotran-enhanced T2*W-GRE and T2W-TSE has additive efficacy for detecting HCC in cirrhotic patients, but T2W-TSE is preferred for detecting metastases in non-cirrhotic patients.

Ferucarbotran-Enhanced MR Imaging of the Radiofrequency Ablation Zones in the Normal Rabbit Liver: Comparison with the Conventional MR Imaging

PURPOSE: We wanted to evaluate the findings of ferucarbotran-enhanced MR imaging of the radiofrequency (RF) ablation zones in normal rabbit livers and we compared the findings with the conventional MR imaging. MATERIALS AND METHODS: RF ablation zones were created in the livers of 12 rabbits in vivo by using a 17-gauge internally cooled electrode with 1-cm active tip, and RF energy (maximum power: 30 Watt) was applied for three minutes. Three rabbits were sacrificed immediately and then at three days, two weeks and six weeks after RF ablation. Before sacrifice, the T1- and T2-weighted images (WI) and the ferucarbotran-enhanced T2*WIs were obtained and compared regarding the signal intensity of ablation zone, the laminar pattern of the signal intensity and the contrast-to-noise ratio (CNR) of the ablation zone to the liver parenchyma. RESULTS: On T1- and T2WIs, the RF ablation zones showed two to four laminar patterns of signal intensity according to the time. Meanwhile, on the ferucarbotran-enhanced T2WIs, the RF ablation zones showed high signal intensity without a laminar pattern regardless of time. The CNRs of the ablation zones to the liver parenchyma on the ferucarbotran-enhanced T2*WIs (18.2+/-5.9) were significantly higher than those of the TIWIs (1.6+/-1.5) and T2WIs (2.7+/-1.9) (p < 0.05). CONCLUSION: On the ferucarbotran-enhanced T2*WI, the RF ablation zones showed high signal intensity without a distinct laminar pattern and significantly higher lesion conspicuity than did the conventional T1- and T2WIs. Therefore, the ferucarbotran-enhanced T2*WI shows the RF ablation zone more accurately and clearly than do the conventional T1- and T2WIs.

Hepatic Hemangiomas with Peritumoral Sparing of Fatty Infiltration in Hepatic Steatosis: Findings on Contrast-enhanced MR Imaging and on Sonography

PURPOSE: We wanted to determine the frequency of peritumoral sparing of fatty infiltration (PTSF) around hepatic hemangioma in hepatic steatosis and to evaluate the finding of these tumors on dynamic contrast-enhanced MR imaging and on sonography. MATERIALS AND METHODS: This study included 76 hemangiomas in 67 patients suffering with hepatic steatosis. A diagnosis of hemangioma was based on the histologic findings, hemangioma SPECT or a compatible enhancement pattern on the dynamic contrast-enhanced MR study. For chemical shifting, PTSF was defined when there wasn't any decrease in signal intensity of the liver parenchyma on the opposed-phase images as compared with the in-phase images, and this intensity appeared as a hyperintense area around the tumor. We evaluated the frequency of PTSF and we analyzed if the presence of PTSF was related to the tumor size, the rapidity of enhancement or an associated arterioportal shunt. Among those, sonographic images were available in 55 hemangiomas. We also evaluated the sonographic appearances of hemangiomas with PTSF. RESULTS: Of the 76 hemangiomas, PTSF was noted on the MR chemical-shift images in 57 hemangiomas (75%). There was no significant relationship between tumor size and the presence of PTSF (p=.578). However, this finding was more frequently found in high-flow hemangiomas than in the slow-flow ones (p=.0038) and it was also related to the presence of associated arterioportal shunt (p=.0158). Sonographically, hemangiomas with PTSF were commonly surrounded by a peritumoral low-echoic area (28/41, 68%); these tumors more frequently showed a thin high-echoic rim on sonography than did the tumors without this finding (p=.0055). CONCLUSION: PTSF is commonly seen in hemangiomas in hepatic steatosis patients. Hepatic hemangiomas with PTSF tend to show rapid enhancement on dynamic MR imaging and this is accompanied by arterioportal shunt. They tend to be seen as an iso- or low-echoic mass with a thin high-echoic rim on sonography, and the mass is commonly surrounded by a peritumoral low-echoic area.

Hepatic Perfusion Disorders: A Pictorial Review of CT and MR Imaging

The liver has a unique dual blood supply through the portal vein and the hepatic artery. There are several communications between these two vessels under various conditions such as in hepatic tumors, trauma and liver cirrhosis, vascular compromise, among others. When vascular compromise occurs, this dual blood supply system can cause changes in the volume of blood flow in individual vessels or even in the direction of blood flow. With rapid image acquisition and increased resolution available in multislice CT and MR imaging, hepatic perfusion disorders are now more frequently encountered than in the past. Familiarity with imaging findings of these perfusion disorders will be helpful in characterizing focal hepatic lesions and will also help to avoid false positive diagnoses.

Quantitative Evaluation of Liver Function with MRI Using Gd-EOB-DTPA

OBJECTIVE: Gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA) is a newly developed MR contrast agent. After intravenous injection, Gd-EOB-DTPA is gradually taken up by the hepatocytes and eventually excreted via the biliary pathway without any change to its chemical structure. Because of these characteristics, it can be used as a tracer for quantitative liver function testing. The purpose of this study is to develop a noninvasive method of quantitation of the hepatic function using Gd-EOB-DTPA through the deconvolution analysis. MATERIALS AND METHODS: Adult New Zealand white rabbits (n = 10, average body weight = 3.5 kg) were used in the present study. Hepatic injury was induced to by the intragastric administration of carbon tetrachloride (CCl4) three times a week for three weeks. Liver enzyme (aspartate aminotransferase, AST; alanine aminotransferase, ALT) levels and the plasma indocyanine green (ICG) retention rate 15 minutes after an intravenous injection of ICG (ICG R15), was checked before and after the three-week administration of CCl4. At the end of experimental period, an observer "blinded" to the treatment given the rabbits performed the histological examination. MRI studies were performed before and after the three-week administration of CCl4 on a 1.5 T scanner using a human extremity coil. After intravenous bolus injection of Gd-EOB-DTPA (0.3 mL of Gd-EOB-DTPA freshly prepared in 2.7 mL of normal saline) through the ear vein, the 250 axial single level dynamic MR images were obtained using a fast low angle shot (FLASH, TR/TE = 11/4.2 msec, flip angle = 15, acquisition time 1 second, slice thickness = 5 mm, matrix = 128x128, field of view = 120 mm) sequence with 1.5 sec time intervals. The time-intensity curves were obtained at the abdominal aorta and the liver parenchyma that was devoid of blood vessels. Deconvolution analysis of the aortic (input function) and hepatic parenchymal (output function) time-intensity curves was performed with a modified Fourier transform technique to calculate the hepatic extraction fraction (HEF). The presence and type of hepatic injury were determined by the histopathologic examination and statistical analysis of the changes of the hepatic enzyme levels, the ICG R15 and Gd-EOB-DTPA HEF values between the time before and after CCl4 administration with Wicoxon signed rank test. Correlation between the Gd-EOB-DTPA HEF and the change of the ICG R15 were analyzed with Pearson's correlation coefficient. RESULTS: Histopathologic examination showed findings that were compatible with hepatic fibrosis caused by chronic liver injury. The initial blood biochemical studies before the administration of carbon tetrachloride showed that the mean AST and ALT levels were 39.8+/-5.2 IU/L and 59.1+/-11.7 IU/L, respectively. The AST and ALT levels increased to 138.4+/-50.5 IU and 172.0+/-71.6 IU/L, respectively, after the three week administration of CCl4. The ALT and AST levels were significantly increased after the three weeks of CCl4 administration (p=0.018). The ICG R15 values were 4.47+/-2.08% and 19.43+/-3.98% before and after three-week administration of CCl4, respectively. The ICG R15 values were significantly increased after hepatic injury (p=0.018). After normalizing the HEF as 100% in each rabbit before CCl4 administration, the deconvoluted curve after CCl4 administration revealed less hepatocyte extraction efficiency with a mean value of 77.7+/-3.6. There was a significant correlation between the HEF and changes of the ICG R15 by the Pearson correlation coefficient assessment (correlation coefficient = -0.965, p=0.000). CONCLUSION: The Gd-EOB-DTPA HEF could be calculated from deconvolution analysis of aortic and hepatic parenchymal time-intensity curves obtained by dynamic MRI. The Gd-EOB-DTPA HEF was well correlated with changes of the ICG R15, which is the most common parameter used in the quantitative estimation of the hepatic function. The Gd-EOB-DTPA HEF is a direct, noninvasive technique for the quantitative evaluation of liver function. It could be a promising alternative for the determination of noninvasive hepatic function in those patients with liver disease.

Are the Delay Images Necessary to Evaluate the Liver Metastatic Lesions on Mangafodipir Trisodium Enhanced Liver MRI?: Comparison with Hepatocellular Carcinomas

PURPOSE: To assess whether ring enhancements of liver metastases on Mn-DPDP enhanced, early MR images were well visualized on delayed images, as compared with those of hepatocellular carcinomas (HCC), and to investigate the detection accuracy and conspicuity of each tumor. MATERIALS AND METHODS: Twenty patients with liver metastases and 15 with HCC were studied by Mn-DPDP enhanced, T1-weighted MR images. Peripheral ring enhancement and conspicuity were investigated. Differences in detection accuracy and frequency of ring enhancement in liver metastases and HCC were assessed. RESULTS: In liver metastases (n=69), 44 cases (63.8%) without ring enhancement and 25 (36.2%) with were noted on early images. Sixteen cases (23.2%) without ring enhancement, 38 (55.1%) with ring enhancement similar to the early images, and 15 (21.7%) with prominent ring enhancement were noted on delayed images. In HCC (n=37), 36 cases (97.3%) without ring enhancement and 1 case (2.7%) with were noted on early images. There was no difference of detection accuracy in liver metastases or HCC between the 2 readings. Ring enhancement and conspicuity of each tumor were superior on delayed images. Ring enhancement in liver metastases was better seen on delayed images. CONCLUSION: Ring enhancement in liver metastases was well presented on Mn-DPDP enhanced, delayed MR images, which was useful to differentiate liver metastases from HCC.

Hepatic Enhancement on Gd-BOPTA-enhanced MR Imaging: Comparison between Cirrhotic and Normal Livers

PURPOSE: To compare the enhancement features of hepatic parenchyma between cirrhotic and normal liver, using Gd-BOPTA-enhanced delayed MR imaging. MATERIALS AND METHODS: The 60 patients (35 with cirrhotic and 25 with normal liver) included in our study underwent Gd-BOPTA-enhanced MR imaging using a 1.5T system with a phase-array multicoil. In all cases, T1-weighted in-phase and opposed-phase gradient-echo MR imaging was performed before and 60 minutes after intravenous administration of a bolus of Gd-BOPTA. All images were quantitatively analysed by comparing the signal-to-noise ratio (SNR) and signal enhancement (SE) of cirrhotic and normal liver before and after contrast enhancement, and in cirrhotic patients, SNR and SE were also compared in terms of the Child-Pugh classification. For qualitative analysis, the hepatic enhancement patterns of cirrhotic and normal liver were classified as homogeneous or heterogeneous according to the consensual findings of two radiologists. RESULTS: At contrast-enhanced imaging, both cirrhotic (p<0.001) and normal liver (p<0.001) showed substantially increased SNR relative to unenhanced images, and the SNR of cirrhotic liver was significantly lower than that of normal livers at both in-phase (p<0.001) and opposed-phase (p<0.001) imaging. The SE of cirrhotic liver was significantly lower than that of normal liver (in-phase: p=0.002; opposed phase: p=0.011). Both Child-Pugh class A (p<0.001) and B (p<0.001) cirrhotic liver showed a substantial increase in SNR at contrast-enhanced imaging relative to unenhanced imaging and the SNR of Child-Pugh class A was significantly higher than that of Child-Pugh class B at both in-phase (p<0.001) and opposed-phase (p=0.022) imaging. In addition, the SE of class A was significantly higher than that of class B at in-phase imaging (p=0.004). Cirrhotic liver showed heterogeneous enhancement in 20 of 35 patients (57%), whereas normal liver showed homogeneous enhancement in all patients. CONCLUSION: At Gd-BOPTA-enhanced delayed MR imaging, cirrhotic liver showed less enhancement than normal liver. In cirrhotic patients, hepatic enhancement and hepatic function decreased in tandem. Gd-BOPTAenhanced delayed MR imaging may be useful for evaluating the functional reserve of the liver.

Double Contrast Media enhanced MRI with Ferumoxides-Gadolinium on Hepatocellular Carcinoma

PURPOSE: To evaluate the effects of Ferumoxides on Gadolinium (Gd) enhanced dynamic liver magnetic resonance imaging (MRI) in cirrhotic patients and also for the diagnosis of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: 29 patients with liver cirrhosis were examined at 1.5T. 12 patients had HCC. The imaging protocol included GE T1 in and opposed phases, and a breath-hold TSE T2 before and 30-60 min following 0.05 ml/kg Ferumoxides. Four dynamic in-phase GE series were also acquired after an injection of 20 ml of Gd at 2 ml/sec. SNR and CNR were calculated for liver lesion relative to the muscle and background liver respectively. Statistical analysis was performed using the paired t-test. RESULTS: The SNR of the liver decreased by 8.6+/-1.20 (p<0.001) after Ferumoxides injection. At the peak of the Gd effect, the liver increased by 6.09+/-1.15 relative to the post Ferumoxides, but it was not significantly different from the pre-Ferumoxides study (p<0.01). Although there was no significant change in post Ferumoxides SNR of HCC, CNR of HCC relative to the liver increased by 7.54+/-1.61 (p<0.05). After the Gd injection, CNR of HCC increased by 15.6+/-3.87 (p<0.05). CONCLUSION: The administration of Ferumoxides made HCC CNR increase, and it canceled the effect of Gd enhancement of the cirrhotic liver. The combination of Ferumoxides and Gd makes HCC CNR increase.

Intrahepatic Cholangiocarcinoma with Sarcomatous Change: Case Report

Cholangiocarcinomas have several histologic types, but intrahepatic cholangiocarcinoma with sarcomatous change is rare. A 71-year-old man was admitted to our hospital because of fever which had lasted two months. Ultrasonography (US) of the upper abdomen demonstrated a huge hepatic mass with central solid and peripheral cystic portions, and computed tomography (CT) revealed a heterogeneous hepatic mass with a central area in which enhancedment was delayed. Magnetic resonance imaging (MRI) disclosed a huge mass of predominantly low signal intensity at T1WI, and peripheral portions of high signal intensity and a central portion of intermediate signal intensity at T2WI. The pathologic diagnosis was cholangiocarcinoma with sarcomatous change.

Detection of Small Hypervascular Hepatocellular Carcinomas in Cirrhotic Patients: Comparison of Superparamagnetic Iron Oxide-Enhanced MR Imaging with Dual-Phase Spiral CT

OBJECTIVE: To compare the performance of superparamagnetic iron oxide (SPIO) -enhanced magnetic resonance (MR) imaging at 1.5T and dual-phase spiral computed tomography (CT) for the depiction of small hypervascular hepatocellular carcinomas (HCCs). MATERIALS AND METHODS: Forty-three patients with 70 small nodular HCCs (5-20 mm; mean, 13.7 mm) were examined. Diagnosis was based on the results of surgical biopsy in 22 patients and by the combined assessment of MR imaging, lipiodol CT, alpha feto-protein levels, and angiographic findings in 21. MR imaging consisted of respiratory-triggered turbo spin-echo T2-weighted imaging, T1-weighted fast low-angle shot, and T2* -weighted fast imaging with steady-state precession imaging before and after SPIO enhancement. CT imaging was performed with 5-mm collimation and 1: 1.4 pitch, and began 30 and 65 secs after the injection of 150 mL of contrast medium at a rate of 3 mL/sec. Two blinded observers reviewed all images independently on a segment-by-segment basis. Diagnostic accuracy was evaluated using receiver operating characteristics (ROC) analysis. RESULT: The mean areas (Az) under the ROC curves were 0.85 for SPIOenhanced MR imaging and 0.79 for dual-phase spiral CT (p .05). CONCLUSION: SPIO-enhanced MR imaging is more sensitive than dual-phase spiral CT for the depiction of small hypervascular hepatocellular carcinomas.

Focal Nodular Hyperplasia with Retraction of Liver Capsule: A Case Report

Focal nodular hyperplasia (FNH) is characterized by the presence a central scar with radiating fibrous septa. Our case had a capsular retraction, which was the result of an extension of the central scar to the surface. In addition, a hypointense scar on the T2-weighted image and a minimal enhancing central scar on the enhanced T1-weighted image, which was due to dense, sclerotic collagenous tissue, were observed. We report the first case of FNH with a capsular retraction.

Enhancement Pattern of Focal Hepatic Tumors with Gadobenate Dimeglumine-Enhanced Delayed MR Imaging

PURPOSE: To investigate the enhancement pattern occurring at delayed gadobenate dimeglumine (Gd-BOPTA) MR imaging, as used to characterize focal hepatic tumors. MATERIALS AND METHODS: Forty patients with 64 focal hepatic tumors (32 hepatocellular carcinomas [HCC], 15 hemangiomas, 14 metastasis and 3 cholangiocarcinomas) underwent MR imaging before and 60 minutes after the intravenous administration of 0.1 ml/kg Gd-BOPTA. For all MR studies, a 1.5-T MR system was used, and T1-weighted in-phase gradient echo (GRE) imaging was porformed. The quantitative assessment of early and delayed images included determination of the signal-to-noise ratio (SNR), tumor-to-liver contrast-to-noise ratio (CNR), and degree of enhancement (DE). Two experienced radiologists evaluated lesion conspicuity and the pattern of contrast enhancement (CE), reaching their conclusions by consensus. RESULTS: At delayed imaging, SNR and CNR showed significant increases (p>0.05), and the DE of all lesions had also increased. Lesion conspicuity, however, was not significantly different between (p>0.05). The most common enhancement patterns seen at delayed imaging were inhomogeneous hypointense in HCCs, homogeneous iso- or hyperintense in hemangiomas, and target-like in metastases. CONCLUSION: At delayed imaging with Gd-BOPTA, tumors of both hepatocytic and non-hepatocytic origin showed enhancement, and in the characterization of focal hepatic lesions, observed differences in enhancement are thus of limited usefulness. However, the observed homogeneous iso- or hyperinteuse enhancement of hemangiomas, and the target-like enhancement of metastases, may help differentiate then from other tumors.

Nodular Regenerative Hyperplasia of the Liver in an Infant: Case Report

Nodular regenerative hyperplasia (NRH) of the liver is an uncommon disease entity, especially in the pediatricage group. A few cases have been reported in the radiologic literature, but follow-up imaging studies are rare. We describe a case of NRH, diagnosed by ultrasound-guided needle biopsy, in a seven-month-old infant with cri-du-chat syndrome. Initial ultrasound revealed several small hypoechogenic nodules in the liver, but CT and MR failed to demonstrate their presence. Two follow-up sonographic examinations were performed 7 and 20 months later, revealing increases in the size and number of the nodules.

MRI after Sequential Use of Gadolinium Chelate and Mangafodipir Trisodium for the Evaluation of Focal Liver Lesions: Study of Image Findings and Safety

PURPOSE: To assess the feasibility of sequentially administering Gd-DTPA and Mn-DPDP for the MR imaging of focal hepatic lesions, and to investigate whether the procedures involved led to any adverse effects. MATERIALS AND METHODS: Forty-two patients (M:F=25:17) with suspected hepatic lesions underwent T1-weighted MR imaging procedures before and after Gd-DTPA enhancement, and after sequential Mn-DPDP administration. Two investigators reviewed the findings in terms of the size, number, morphology, and enhancement patterns of the lesions. Any adverse actions resulting from the procedures were noted. RESULTS: Fifteen patients had hepatocellular carcinoma (HCC, n=35), 13 showed liver metastases (n=40), nine had hemangioma (n=13), two had cholangiocarcinoma (CC, n=2), two had a liver abscess (n=2), and one had focal nodular hyperplasia (FNH, n=2). All focal hepatic lesions were clearly visible, with no difference in conspicuity between T1-weighted images obtained after Gd-DTPA administration and those obtained after Gd- DTPA plus Mn-DPDP administration. After the latter procedure, 12 HCCs showed high or iso- signal intensity to liver parenchyma and 23 showed no contrast enhancement. Thirty-eight liver metastases showed no contrast enhancement, but in two cases ring enhancement was observeed. In both cases of FNH, homogeneous enhancement was noted. No hemangiomas, CCs or abscesses demonstrated contrast enhancement. The only adverse reaction was five instances of facial flushing. CONCLUSION: Hepatic MR imaging after sequential Gd-DTPA plus Mn-DPDP administration may be selectively useful in differentiating between hepatocellular and non-hepatocellular tumor. No technical difficulties or severe adverse reactions were encountered.

Mangafodipir Trisodium (Mn-DPDP)-Enhanced MR Imaging of Hepatocellular Carcinoma: Correlation with Histopathological Findings

PURPOSE: To correlate the contrast enhancement pattern of hepatocellular carcinoma (HCC) seen at mangafodipir trisodium (Mn-DPDP)-enhanced MR imaging with the histopathologic findings. MATERIALS AND METHODS: In 28 patients with 36 HCCs larger than 1 cm, Mn-DPDP-enhanced T1-weighted fast multiplanar spoiled gradient-recalled echo (GRE) MR images were obtained before and 15 mins after Mn-DPDP administration. Qualitative analysis focused on signal intensity (hyper-, iso-, or hypo-) relative to surrounding liver parenchyma, while the signal enhancement ratio [ER (%)] and lesion-to-liver contrast-noise ratio (CNR) were determined quantitatively. Signal intensity relative to surrounding liver parenchyma, lesion-to-liver CNR and signal ER of the lesions were correlated with their size and histopathologic grade. RESULTS: The imaging procedure showed that relative to surrounding liver parenchyma, 74% (14/19) of HCCs 1-3 cm in size but 47% (8/17) of those larger than 3 cm were hyperintense. There was, however, no significant difference between the two groups (p>0.05). In addition, 35% (6/17) of HCCs larger than 3 cm but none of the 19 smaller lesions were hypointense, with a significant difference between the two groups (p0.05). CONCLUSION: At Mn-DPDP-enhanced MR imaging, HCCs 1-3 cm in size showed greater signal intensity and signal ER than HCCs larger than 3 cm. Well or moderately differentiated HCCs showed greater signal ER than those that were poorly differentiated. Lesion-to-liver CNR did not differ according to lesion size and histopathologic grade.

Mn-DPDP-enhanced MR Imaging: the Optimal Pulse Sequence for Detection of Focal Hepatic Tumor

PURPOSE: To assess the diagnostic value of Mn-DPDP for the detection of focal hepatic tumors on MR images and to determine the optimal pulse sequence to maximize its effect. MATERIALS AND METHODS: Twenty-three patients with 32 focal hepatic tumors were examined by means of 1.5-T MRI. Before and after the intravenous administration of Mn-DPDP, five pulse sequences were used to obtain T1-weighted images: two-dimensional fast low-angle shot (2D FLASH) with/without fat saturation (FS), spinecho (SE), and three-dimensional fast low angle shot reconstruction (3D FLASH) with/without FS. Quantitative assessment involved determination of the signal-to-noise ratio (SNR) of the liver and the tumor, the percentage signal enhancement ratio (PSER) of the liver, and tumor-to-liver contrast to noise ratio (CNR). Pulse sequences were also evaluated subjectively for tumor conspicuity, delineation, and image artifact. In addition, two experienced radiologists compared tumor detection rates between precontrast and postcontrast images. RESULTS: Mn-DPDP had a marked effect on liver SNR and absolute CNR at all pulse sequences (p<0.05). On postcontrast images, PSER and absolute CNR of the liver were highest at 3D FLASH and 2D FLASH FS, respectively, and significantly higher at GRE than at SE (p<0.05). On postcontrast images, the CNR of focal nodular hyperplasia and hepatocellular carcinoma was positive, while that of hemangioma, metastasis and cholangiocarcinoma was negative. The postcontrast CNR of all tumors except hepatocellular carcinoma increased more than 100%. Qualitative studies showed that tumor conspicuity increased significantly at all sequences except SE, and delineation increased significantly except at SE and postcontrast 2D GRE FS. After Mn-DPDP, GRE more effectively demonstrated tumor conspicuity and image artifact than did SE, and GRE other than 2D FLASH FS was also better than SE for tumor dilineation (p<0.05). The sensitivity of all postcontrast images increased and the tumor detection rate at GRE was significantly higher than at SE. CONCLUSION: Mn-DPDP favorably affects tumor-to-liver contrast, and may be useful in the imaging of focal hepatic tumors, more so with 2D or 3D FLASH pulse sequences than with SE.

Peliosis Hepatis Mimicking Single Hepatic Mass: A Case Report

Peliosis hepatis is a rare disease characterized by cystic hepatic sinusoidal dilatation and the presence of multiple blood-filled spaces in the hepatic parenchyma. In most cases, multiple lesions and individual cysts not exceeding 1cm in diameter occur. We report a case in which the condition occurred in a 33-year-old woman who presented with general weakness and in whom a 3.5 cm-sized single hepatic mass was discovered incidentally at ultrasonography. The radiologic features mimicked those of a signle hepatic mass.

Hepatic Arterioportal Shunts: Dynamic CT and MR Features

With the increased temporal resolution available in dynamic computed tomography (CT) and magnetic resonance imaging (MRI), hepatic arterioportal shunts are now more frequently encountered than in the past. The condition occurs in various hepatic diseases in which portal or hepatic venous flow is compromised. The underlying mechanism and the degree of shunt affect its appearance at dynamic imaging. The dynamic CT and MRI findings have been summarized as early enhancement of peripheral portal veins, and wedge-shaped transient parenchymal enhancement during the hepatic arterial phase. Recognition of arterioportal shunt can suggest the presence of a previously unsuspected disorder and avoids false-positive diagnosis or overestimation of a hepatic disease. Familiarity with the pathophysiology of arterioportal shunt also allows investigation of the hepatic hemodynamic changes occurring in various hepatic diseases.

Atypical Hepatic Angiomyolipoma: CT and MR Findings: A Case Report

Hepatic angiomyolipoma is a rare benign lipomatous tumor of the liver. Radiologic studies usually reveal a fat component, but since this may be minimal, such a component is not always detected. We report a case of atypical hepatic angiomyolipoma which because of the non-visualization of fat at CT and MR imaging, was difficult to differentiate from other hypervascular tumors.