Akihiko Kanki

Gd-EOB-DTPA-enhanced MR imaging: Evaluation of hepatic enhancement effects in normal and cirrhotic livers

OBJECTIVE The purpose of this study was to assess differences in enhancement effects of liver parenchyma between normal and cirrhotic livers on contrast-enhanced MR imaging (CE-MRI) obtained with Gd-EOB-DTPA. METHODS A total of 99 patients with cirrhotic liver (n=58; Child-Pugh class A, n=30; B, n=22; C, n=6) and normal liver (n=41) underwent Gd-EOB-DTPA-enhanced MR imaging. CE images were obtained before contrast injection, in the arterial phase (AP) at 25s or modified scan delay, in the portal phase (PP) at 70s, in the equilibrium phase (EP) at 3 min, and in the hepatobiliary phase (HP) at 3 times (10, 15 and 20 min). Signal intensity of the liver in all phases was defined using region-of-interest measurements for relative enhancement (RE) calculation. RESULTS In normal-liver and Child-Pugh class A and B patients, mean RE of liver parenchyma increased significantly (P<0.03-0.001) with time until 20-min HP. Conversely, mean RE for Child-Pugh class C patients did not show any increasing tendency after PP. Mean RE of liver parenchyma at EP and HP (10-, 15- and 20-min) was highest in normal liver, followed by Child-Pugh class A, B and C cirrhosis (P<0.02-0.001). CONCLUSION Hepatic parenchymal enhancement on CE-MR images obtained using Gd-EOB-DTPA is affected by the severity of cirrhosis.

Gd-EOB-DTPA enhanced MR imaging: evaluation of biliary and renal excretion in normal and cirrhotic livers.

OBJECTIVE The purpose of this study was to assess the difference in the activity of biliary and renal excretion between normal and cirrhotic livers on contrast-enhanced MR imaging obtained with gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA). METHODS A total of 78 patients with cirrhotic liver (n=44) and with normal liver (n=34) underwent multi-phase Gd-EOB-DTPA enhanced MR imaging (arterial, portal, equilibrium, and three hepatobiliary phases (10, 15 and 20 min HP), respectively), and these contrast-enhanced images were qualitatively and quantitatively evaluated for the differences of the biliary and renal excretion between normal and cirrhotic livers. RESULTS The timing of biliary excretion of contrast agents in the cirrhotic liver was significantly slower than that in the normal liver (P<0.001). The degree of contrast enhancement in the common bile duct in the normal liver was significantly better than that in the cirrhotic liver (P=0.003). Contrast agents were demonstrated in the duodenum at 20 min HP in 8/44 (18%) cirrhotic liver while they were seen in 15/34 (44%) normal liver (P=0.013). The enhancement effects of renal medulla and portal vein at 20 min HP in the cirrhotic liver were significantly higher than those of normal liver (P=0.043 and P<0.001, respectively). CONCLUSION Biliary excretion of Gd-EOB-DPTA was impaired in cirrhotic livers in comparison with normal livers while renal excretion of Gd-EOB-DPTA was increased.

Hepatic Hemangiomas: Evaluation of Enhancement Patterns at Dynamic MRI With Gadoxetate Disodium

OBJECTIVE The aim of this retrospective study was to assess the enhancement patterns of hepatic hemangiomas on gadoxetate disodium. MATERIALS AND METHODS A total of 22 patients with 32 hepatic hemangiomas (23 typical type and nine high-flow type) in normal liver underwent gadoxetate disodium-enhanced MRI. Contrast-enhanced images were obtained before and after contrast injection, including arterial phase, portal phase, equilibrium phase, and three hepatobiliary phases (10, 15 and 20 minutes). Signal-to-phantom ratios of hemangiomas and the portal vein as well as lesion-to-liver contrast-to-phantom ratios were assessed. RESULTS Mean signal-to-phantom ratios of all 32 hemangiomas showed the highest value on the arterial phase and subsequently decreased over time (p = 0.029 to p < 0.001). Mean lesion-to-liver contrast-to-phantom ratios of all 32 hemangiomas showed a positive value during the arterial phase and increasingly negative values at later time points (p = 0.001 to p < 0.001). The enhancement pattern of hemangiomas was equal to that of the portal vein at all time points. There was no significant difference in signal-to-phantom ratio between typical hemangiomas and high-flow hemangiomas at any time point. CONCLUSION Most hepatic hemangiomas showed hypointensity relative to surrounding liver parenchyma during the equilibrium phase and the hepatobiliary phase. In addition, hepatic hemangiomas showed a signal intensity matching the portal vein at all phases, a finding we believe may be characteristic for hepatic hemangiomas on gadoxetate disodium-enhanced MR images.

Potential clinical factors affecting hepatobiliary enhancement at Gd-EOB-DTPA-enhanced MR imaging.

OBJECTIVE The objective was to clarify the clinical factors that might affect the degree of hepatic parenchymal enhancement at gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance (MR) imaging. MATERIALS AND METHODS A total of 84 patients with (n=63) and without chronic liver disease (n=21) underwent Gd-EOB-DTPA-enhanced MR imaging. Contrast-enhanced MR images of hepatobiliary phase (HP) were obtained at 20 min after Gd-EOB-DTPA administration. The relative enhancement (RE) of liver parenchyma at 20 min HP was calculated from region of interest measurements at each patient. Then, these results were correlated with various clinical parameters using Pearson correlation coefficient or Spearman rank correlation coefficient. Furthermore, the predictor of the degree of hepatic parenchymal enhancement was determined using multiple regression analysis. RESULTS The presence or absence of chronic liver disease (P=.002), ascites (P=.005) and splenomegaly (P=.027), and the values of prothrombin activity (P=.008), total bilirubin (T-Bil) (P=.001), albumin (P=.001), aspartate aminotransferase (AST) (P=.002) and cholinesterase (P=.007) were significantly correlated with the RE of liver parenchyma at 20 min HP. Among these parameters, increases of T-Bil (P=.011 to .028) and AST (P=.018 to .049) were predictors of decreased hepatic parenchymal enhancement. CONCLUSIONS Hepatic parenchymal enhancement of Gd-EOB-DTPA was affected by various clinical parameters. Impaired hepatobiliary enhancement may be predicted by routine biochemical tests, such as T-Bil and AST.

High-risk nodules detected in the hepatobiliary phase of Gd-EOB-DTPA-enhanced MR imaging in cirrhosis or chronic hepatitis: incidence and predictive factors for hypervascular transformation, preliminary results.

To evaluate the incidence and predictive factors of hypervascular transformation during follow‐up of “high‐risk nodules” detected in the hepatobiliary phase of initial Gd‐EOB‐DTPA‐enhanced MRI in chronic liver disease patients.

Imaging Outcomes of Liver Imaging Reporting and Data System Version 2014 Category 2, 3, and 4 Observations Detected at CT and MR Imaging

Purpose To determine the proportion of untreated Liver Imaging Reporting and Data System (LI-RADS) version 2014 category 2, 3, and 4 observations that progress, remain stable, or decrease in category and to compare the cumulative incidence of progression in category. Materials and Methods In this retrospective, longitudinal, single-center, HIPAA-compliant, institutional review board-approved study, 157 patients (86 men and 71 women; mean age ± standard deviation, 59.0 years ± 9.7) underwent two or more multiphasic computed tomographic (CT) or magnetic resonance (MR) imaging examinations for hepatocellular carcinoma surveillance, with the first examination in 2011 or 2012. One radiologist reviewed baseline and follow-up CT and MR images (mean follow-up, 614 days). LI-RADS categories issued in the clinical reports by using version 1.0 or version 2013 were converted to version 2014 retrospectively; category modifications were verified with another radiologist. For index category LR-2, LR-3, and LR-4 observations, the proportions that progressed, remained stable, or decreased in category were calculated. Cumulative incidence curves for progression were compared according to baseline LI-RADS category (by using log-rank tests). Results All 63 index LR-2 observations remained stable or decreased in category. Among 166 index LR-3 observations, seven (4%) progressed to LR-5, and eight (5%) progressed to LR-4. Among 52 index LR-4 observations, 20 (38%) progressed to a malignant category. The cumulative incidence of progression to a malignant category was higher for index LR-4 observations than for index LR-3 or LR-2 observations (each P < .001) but was not different between LR-3 and LR-2 observations (P = .155). The cumulative incidence of progression to at least category LR-4 was trend-level higher for index LR-3 observations than for LR-2 observations (P = .0502). Conclusion Observations classified according to LI-RADS version 2014 categories are associated with different imaging outcomes. (©) RSNA, 2016 Online supplemental material is available for this article.

Hepatic parenchymal enhancement at Gd-EOB-DTPA-enhanced MR imaging: correlation with morphological grading of severity in cirrhosis and chronic hepatitis

The aim was to clarify whether enhancement effects of the liver parenchyma in the hepatobiliary phase (HP) of gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced MR imaging were correlated with the morphological grading of the severity in cirrhosis. A total of 62 patients with chronic hepatitis or cirrhosis underwent Gd-EOB-DTPA-enhanced MR imaging. Relative enhancement (RE) of liver parenchyma was calculated from signal intensity (SI) measurements obtained at precontrast images (SIpre) and 20-min postcontrast HP images (SIpost) as: (SIpost-SIpre)/SIpre. Morphological MR grades of severity in cirrhosis were divided into four groups. Then, RE of liver parenchyma and morphologic MR grading were correlated. Regarding the morphologic severity of cirrhosis, the numbers of patients with MR grade 1, 2, 3 and 4 were 14 (23%), 7 (11%), 28 (45%) and 13 (21%), respectively. The mean REs of liver parenchyma in each group of MR morphologic grade 1, 2, 3 and 4 were 0.71±0.21, 0.62±0.16, 0.70±0.22 and 0.77±0.18, respectively. There was no significant correlation between the MR grading of morphologic severity and the RE of liver parenchyma at 20-min HP. Hepatic parenchymal enhancement in the HP of Gd-EOB-DTPA-enhanced MR imaging did not necessarily decrease according to the severity of morphologic changes in cirrhosis. This fact may suggest that the hepatic uptake of Gd-EOB-DTPA depends on the preserved hepatocytes function rather than the severity of morphologic changes in cirrhosis.

Comparison of three different injection methods for arterial phase of Gd-EOB-DTPA enhanced MR imaging of the liver

OBJECTIVE To compare three different injection methods for optimizing hepatic arterial phase of gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA) enhanced MR imaging. METHODS Arterial phase images were obtained after the injection of contrast agent at a rate of 3 mL/s with diluted Gd-EOB-DTPA (dilution method) in 27 patients, 3 mL/s with undiluted Gd-EOB-DTPA (3 mL method) in 26 patients and 1 mL/s with undiluted Gd-EOB-DTPA (1 mL method) in 28 patients. In the quantitative evaluation, signal-to-phantom ratios (SPR) of the liver parenchyma, pancreas, renal cortex, portal vein and aorta were evaluated. In the qualitative evaluation, the seven items for image quality of hepatic arterial phase were assessed, and the total score of all items in each subject was calculated. RESULTS The score of enhancement of abdominal aorta and total score of seven items in 1 mL method were significantly higher than those in 3 mL method. The SPR of the liver parenchyma in 3 mL method was significantly higher than that in 1 mL method, suggesting substantial hepatic inflow from portal venous return. CONCLUSION For the optimal arterial phase imaging, injection rate of 1 mL/s with undiluted Gd-EOB-DTPA is convenient and preferable, compared with other two methods, based on our qualitative analysis.

Age-related changes in normal adult pancreas: MR imaging evaluation.

OBJECTIVE To investigate age-related changes in normal adult pancreas as identified by magnetic resonance imaging (MRI). MATERIALS AND METHODS We examined 115 patients without pancreatic diseases (21-90 years) who underwent upper abdominal MRI to evaluate the normal pancreatic MRI findings related to aging. The parameters examined were the pancreatic anteroposterior (AP) diameter, pancreatic lobulation, pancreatic signal intensity (SI), depiction of the main pancreatic duct (MPD), grade of the visual SI decrease on the opposed-phase T1-weighted images compared with in-phase images, and enhancement effect of the pancreas in the arterial phase of dynamic imaging. RESULTS The pancreatic AP diameter significantly reduced (head, p=0.0172; body, p=0.0007; tail, p<0.0001), and lobulation (p<0.0001) and parenchymal fatty change (p<0.0001) became more evident with aging. No significant correlation was observed between aging and pancreatic SI, however the SI on the in-phase T1-weighted images tended to decrease with aging. No significant correlation was observed between aging and the depiction of the MPD as well as aging and contrast enhancement. CONCLUSION MRI findings of pancreatic atrophy, lobulation, and fatty degeneration are characteristic changes related to aging, and it is necessary to recognize these changes in the interpretation of abdominal MRI in patients with and without pancreatic disease.

Newly Developed Hypervascular Hepatocellular Carcinoma During Follow-Up Periods in Patients With Chronic Liver Disease: Observation in Serial Gadoxetic Acid–Enhanced MRI

OBJECTIVE The purpose of our study was to evaluate the process and frequency of newly developed hypervascular hepatocellular carcinoma (HCC) in serial gadoxetic acid-enhanced MRI examinations in patients with chronic liver disease during clinical follow-up periods. MATERIALS AND METHODS After review of 341 MRI examinations in 100 patients with chronic liver diseases who underwent gadoxetic acid-enhanced MRI at least twice during the observation period, 32 newly developed hypervascular HCCs in 14 patients were retrospectively evaluated. Serial MRI examinations before detecting hypervascular HCC were evaluated to determine whether hypervascular HCC showed the presence of a hypointense nodule on the hepatobiliary phase and hypovascularity (high-risk nodule) before hyper-vascularization. The size of newly developed hypervascular HCCs and the duration of hyper-vascularization from initial detection of a high-risk nodule were compared between HCCs with and without the presence of a high-risk nodule. RESULTS Eleven (34.4%) of 32 newly developed hypervascular HCCs had the presence of high-risk nodule before hypervascularization. The size of newly developed hypervascular HCCs was significantly smaller in HCC with high-risk nodule presence (mean, 9.5 mm) than in HCC without the presence of high-risk nodule (mean, 16.4 mm) (p = 0.004). In hypervascular HCCs with high-risk nodule presence, the mean duration of hypervascularization from initial high-risk nodule was 330.7 days, with mean size change from 5.4 mm of high-risk nodules to 9.5 mm of hypervascular HCCs. CONCLUSION Approximately one third of newly developed hypervascular HCCs had the presence of high-risk nodule before hypervascularization in the serial gadoxetic acid-enhanced MRI examinations. High-risk nodule tended to develop into hypervascular HCC after having almost doubled in size during 1 year of high-risk nodule presence.