Hypointense hepatocellular nodules on hepatobiliary phase of Gd‐EOB‐DTPA‐enhanced MRI: Can increasing the flip angle improve conspicuity of lesions?

Purpose:

To compare the conspicuity of hypointense hepatocellular nodules in patients with chronic liver disease on hepatobiliary phase (HP) of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd‐EOB‐DTPA)‐enhanced magnetic resonance imaging (MRI) acquired with low to high flip angles (FAs).

Materials and Methods:

A total of 95 patients with chronic liver disease who underwent Gd‐EOB‐DTPA‐enhanced MRI were included. HP images were obtained at 20 minutes, with 15°, 20°, and 30° FAs. For the detected hepatocellular nodule, liver‐to‐lesion contrast‐to‐phantom ratios (CPR) and lesion conspicuity (LCS) were assessed.

Results:

In all examinations, 96 hepatocellular nodules showing hypointensity on HP were identified. These lesions included 39 hypovascular nodules and 57 hypervascular nodules. Mean CPR and LCS showed the highest value on the 30° FA, followed by 20° and 15° FAs. CPR and LCS of 15° FA were significantly lower than those of 20° and 30° FAs (P < 0.001 to P = 0.007). CPR of 30° FA for hypervascular nodules was significantly greater than that of 20° FA (P < 0.001).

Conclusion:

In the evaluation of hypointense hepatocellular nodules on HP of Gd‐EOB‐DTPA‐enhanced MRI, higher FA such as 30° should be used rather than low FA such as 15°. J. Magn. Reson. Imaging 2013;37:1093–1099. © 2012 Wiley Periodicals, Inc.     

Which is the best MRI marker of malignancy for atypical cirrhotic nodules: Hypointensity in hepatobiliary phase alone or combined with other features? Classification after Gd‐EOB‐DTPA administration

Purpose:

To investigate whether the malignancy of atypical nodules in cirrhosis can be identified at gadoxetic‐acid‐disodium(Gd‐EOB‐DTPA)‐MRI by their hypointensity in the hepatobiliary(HB)‐phase alone or combined with any other MR imaging features.

Materials and Methods:

One hundred eleven atypical nodules detected in 77 consecutive Gd‐EOB‐DTPA‐MRIs were divided, based on arterial‐phase behavior, into: Class I, isovascular (n = 82), and Class II, hypervascular without portal/delayed washout (n = 29). The two classes were further grouped based on HB‐phase intensity (A/B/C hypo/iso/hyperintensity). Portal/venous/equilibrium‐phase behavior and T2w features were also collected. Histology was the gold standard. Per‐nodule sensitivity, specificity, negative and positive predictive values (NPV/PPV), and diagnostic accuracy were calculated for HB‐phase hypointensity alone, and combined with vascular patterns and T2w hyperintensity.

Results:

Histology detected 60 benign and 51 malignant/premalignant nodules [10 overt hepatocellular carcinomas (HCCs) and 41 high‐grade dysplastic nodules (HGDN)/early HCC]. Class IA contained 31 (94%) malignancies, IB one (3%), and IC only benign lesions. Class IIA had 100% malignancies, IIB three (37.5%) and IIC only two (28.5%). HB‐phase hypointensity alone (Classes I–IIA) had 88% sensitivity, 91% NPV, and 93% diagnostic accuracy, superior (P < 0.05, P < 0.006, and P < 0.05, respectively) to any other MR imaging feature alone or combined.

Conclusion:

In atypical cirrhotic nodules, HB‐phase hypointensity by itself is the strongest marker of malignancy. J. Magn. Reson. Imaging 2012;36:648–657. © 2012 Wiley Periodicals, Inc.     

Dilution method of gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd‐EOB‐DTPA)‐enhanced magnetic resonance imaging (MRI)

Purpose

To elucidate whether a contrast agent dilution method (dilution method), in which gadoxetate disodium (Gd‐EOB‐DTPA) is diluted with saline, is useful for good‐quality arterial‐phase images.

Materials and Methods

In this study we observed 494 hypervascular hepatocellular carcinomas (HCCs) in 327 patients with chronic liver disease. Three Gd‐EOB‐DTPA injection methods were adopted for comparison: 1) test injection method (undiluted Gd‐EOB‐DTPA and modified scan delay), in which a test dose of 0.5 mL of Gd‐EOB‐DTPA was injected to determine scan delay; 2) conventional method (undiluted Gd‐EOB‐DTPA and fixed scan delay); and ( 3 ) dilution method (diluted Gd‐EOB‐DTPA and fixed scan delay), in which Gd‐EOB‐DTPA was diluted to 20 mL with saline. Lesion‐liver contrast was calculated. Image quality and lesion detectability were evaluated by two radiologists blinded to the injection methods.

Results

The lesion‐liver contrast of the dilution method was significantly higher than that of the other two methods. Lesion detectability of the conventional method (64%) was significantly lower than that of the other two methods (contrast agent dilution method, 95%; test injection method, 93%). The image quality of the contrast agent dilution method was significantly better than that of the other two methods.

Conclusion

The dilution method contributed to improved image quality, high lesion‐liver contrast, and high lesion detectability in the arterial‐phase images of GD‐EOB‐DTPA‐enhanced MRI. J. Magn. Reson. Imaging 2009;30:849–854. © 2009 Wiley‐Liss, Inc.     

Incidence for progression of hypervascular HCC in hypovascular hepatic nodules showing hyperintensity on gadoxetic acid-enhanced hepatobiliary phase in patients with chronic liver diseases

Purpose

The purpose of this study was to elucidate the incidence and risk factors for the progression of hyperintense nodules, observed in the hepatobiliary phase of gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging (Gd-EOB-DTPA-enhanced MRI), to hypervascular hepatocellular carcinoma (HCC).

Materials and methods

Hypovascular nodules (n = 157) showing hyperintensity in the hepatobiliary phase of Gd-EOB-DTPA-enhanced MRI were examined in 41 patients. All patients underwent computed tomography (CT) during hepatic arteriography and CT during arterial portography within one month of Gd-EOB-DTPA-enhanced MRI. The incidence of progression to hypervascular or classical HCC was calculated using the Kaplan–Meier method.

Results

Tumor size was determined by univariate and multivariate analysis to be an important risk factor of hypervascularization (p = 0.041, odds ratio 1.135). The cumulative incidences of hypervascularization in hypovascular nodules showing hyperintensity on the hepatobiliary phase of Gd-EOB-DTPA-enhanced MRI were 2.4, 4.5, and 6.2 % at 12, 24, and 36 months, respectively. The incidence of hypervascularization was significantly increased in nodules >10 mm in diameter (p = 0.00035).

Conclusion

In patients with chronic liver disease, hypovascular nodules presenting as hyperintense in the hepatobiliary phase of Gd-EOB-DTPA-enhanced MRI and >10 mm in diameter have malignant potential for progression to hypervascular HCC and require careful management.     

Gadoxetic acid disodium-enhanced magnetic resonance imaging for biliary and vascular evaluations in preoperative living liver donors: comparison with gadobenate dimeglumine-enhanced MRI

Purpose

To compare gadoxetic acid disodium (Gd‐EOB‐DTPA)‐enhanced magnetic resonance imaging (MRI) with gadobenate dimeglumine (Gd‐BOPTA)‐enhanced MRI in preoperative living liver donors for the evaluation of vascular and biliary variations.

Materials and Methods

Sixty‐two living liver donors who underwent preoperative MRI were included in this study. Thirty‐one patients underwent MRI with Gd‐EOB‐DTPA enhancement, and the other 31 underwent MRI with Gd‐BOPTA enhancement. Two abdominal radiologists retrospectively reviewed dynamic T1‐weighted and T1‐weighted MR cholangiography images and ranked overall image qualities for the depiction of the hepatic artery, portal vein, hepatic vein, and bile duct on a 5‐point scale and determined the presence and types of normal variations in each dynamic phase. Semiquantitative analysis for bile duct visualization was also conducted by calculating bile duct‐to‐liver contrast ratios.

Results

No statistical differences were found between the two contrast media in terms of hepatic artery or bile duct image quality by the two reviewers, or in terms of portal vein image quality by one reviewer (P > 0.05). Gd‐BOPTA provided better image qualities than Gd‐EOB‐DTPA for the depiction of hepatic veins by both reviewers, and for the depiction of portal veins by one reviewer (P < 0.01). The two contrast media‐enhanced images had similar bile duct‐to‐liver contrast ratios (P > 0.05). Regarding diagnostic accuracies with hepatic vascular/biliary branching types, no significant differences were observed between the two contrast media (P > 0.05).

Conclusion

Gd‐EOB‐DTPA could be as useful as Gd‐BOPTA for the preoperative evaluation of living liver donors, and has the advantage of early hepatobiliary phase image acquisition. J. Magn. Reson. Imaging 2011;33:149–159. © 2010 Wiley‐Liss, Inc.     

Gadoxetic acid-enhanced MRI findings of early hepatocellular carcinoma as defined by new histologic criteria

Purpose:

To describe the imaging features of early hepatocellular carcinoma (HCC) on gadoxetic acid‐enhanced MRI (Gd‐EOB‐MRI) in comparison with multidetector computed tomography (MDCT) examinations.

Materials and Methods:

We analyzed imaging findings of 19 pathologically proven early HCC lesions in 15 patients who underwent both MDCT and Gd‐EOB‐MRI at 3.0 Tesla (T) units before surgery. MRI included in‐phase and out‐of‐phase T1‐weighted dual‐echo gradient‐recalled‐echo sequences, dynamic T1‐weighted images before and after bolus injection of gadoxetic acid disodium, fat‐saturated T2‐weighted fast spin‐echo sequences, and T1‐weighted hepatobiliary phase images 20 min after contrast injection. Two radiologists retrospectively evaluated the signal intensities and enhancement features on MRI and MDCT.

Results:

None of the lesions displayed arterial enhancement and washout on MDCT. On Gd‐EOB‐MRI, six (32%) lesions showed T2‐hyperintensity, five (26%) lesions showed signal drop on opposed‐phase. Three lesions (16%) showed arterial enhancement and washout. Twelve (63%), 13 (68%), and 15 (79%) lesions were hypointense on hepatic venous, equilibrium, and hepatobiliary phase, respectively.

Conclusion:

Most early HCCs did not show arterial enhancement and washout pattern on both MDCT and Gd‐EOB‐MRI. Gd‐EOB‐MRI may provide several ancillary findings for diagnosis of early HCC such as decreased hepatobiliary uptake, T2 hyperintensity and signal drop in opposed phase. J. Magn. Reson. Imaging 2012;393‐398. © 2011 Wiley Periodicals, Inc.     

Dynamic contrast‐enhanced magnetic resonance imaging of abdominal solid organ and major vessel: Comparison of enhancement effect between Gd‐EOB‐DTPA and Gd‐DTPA

Purpose

To evaluate the differences in enhancement of the abdominal solid organ and the major vessel on dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI) obtained with gadolinium ethoxybenzyldiethylenetriamine pentaacetic acid (Gd‐EOB‐DTPA: EOB) and gadolinium diethylenetriamine pentaacetic acid (Gd‐DTPA) in the same patients.

Materials and Methods

A total of 13 healthy volunteers underwent repeat assessments of abdominal MR examinations with DCE‐MRI using either Gd‐DTPA at a dose of 0.1 mmol/kg body weight or EOB at a dose of 0.025 mmol/kg body weight. DCE images were obtained at precontrast injection and in the arterial phase (AP: 25 seconds), portal phase (PP: 70 seconds), and equilibrium phase (EP: 3 minutes). The signal intensities (SIs) of liver at AP, PP, and EP; the SIs of spleen, renal cortex, renal medulla, pancreas, adrenal gland, aorta at AP; and the SIs of portal vein and inferior vena cava (IVC) at PP were defined using region‐of‐interest measurements, and were used for calculation of signal intensity ratio (SIR).

Results

The mean SIRs of liver (0.195 ± 0.140), spleen (1.35 ± 0.353), renal cortex (1.58 ± 0.517), renal medulla (0.548 ± 0.259), pancreas (0.540 ± 0.183), adrenal gland (1.04 ± 0.405), and aorta (2.44 ± 0.648) at AP as well as the mean SIRs of portal vein (1.85 ± 0.477) and IVC (1.16 ± 0.187) at PP in the EOB images were significantly lower than those (0.337 ± 0.200, 1.99 ± 0.443, 2.01 ± 0.474, 0.742 ± 0.336, 0.771 ± 0.227, 1.26 ± 0.442, 3.22 ± 1.20, 2.73 ± 0.429, and 1.68 ± 0.366, respectively) in the Gd‐DTPA images (P < 0.05 each). There was no significant difference in mean SIR of liver at PP between EOB (0.529 ± 0.124) and Gd‐DTPA (0.564 ± 0.139). Conversely, the mean SIR of liver at EP was significantly higher with EOB (0.576 ± 0.167) than with Gd‐DTPA (0.396 ± 0.093) (P < 0.001).

Conclusion

Lower arterial vascular and parenchymal enhancement with Gd‐EOB, as compared with Gd‐DTPA, may require reassessment of its dose, despite the higher late venous phase liver parenchymal enhancement. J. Magn. Reson. Imaging 2009;29:636–640. © 2009 Wiley‐Liss, Inc.     

Different signal intensity at Gd-EOB-DTPA compared with Gd-DTPA-enhanced MRI in hepatocellular carcinoma transgenic mouse model in delayed phase hepatobiliary imaging

Purpose:

To evaluate hyperintense Gd‐DTPA‐ compared with hyper‐ and hypointense Gd‐EOB‐DTPA‐enhanced magnet resonance imaging (MRI) in c‐myc/TGFα transgenic mice for detecting hepatocellular carcinoma (HCC).

Materials And Methods:

Twenty HCC‐bearing transgenic mice with overexpression of the protooncogene c‐myc and transforming growth factor‐alpha (TGF‐α) were analyzed. MRI was performed using a 3‐T MRI scanner and an MRI coil. The imaging protocol included Gd‐DTPA‐ and Gd‐EOB‐DTPA‐enhanced T1‐weighted images. The statistically evaluated parameters are signal intensity (SI), signal intensity ratio (SIR), contrast‐to‐noise ratio (CNR), percentage enhancement (PE), and signal‐to‐noise ratio (SNR).

Results:

On Gd‐DTPA‐enhanced MRI compared with Gd‐EOB‐DTPA‐enhanced MRI, the SI of liver was 265.02 to 573.02 and of HCC 350.84 to either hyperintense with 757.1 or hypointense with 372.55 enhancement. Evaluated parameters were SNR of HCC 50.1 to 56.5/111.5 and SNR of liver parenchyma 37.8 to 85.8, SIR 1.32 to 1.31/0.64, CNR 12.2 to 26.1/?30.08 and PE 42.08% to 80.5/?98.2%, (P < 0.05).

Conclusion:

Gd‐EOB‐DTPA is superior to Gd‐DTPA for detecting HCC in contrast agent‐enhanced MRI in the c‐myc/TGFα transgenic mouse model and there was no difference between the hyperintense or hypointense appearance of HCC. Either way, HCCs can easily be distinguished from liver parenchyma in mice. J. Magn. Reson. Imaging 2012;35:1397–1402. © 2012 Wiley Periodicals, Inc.

     

Hepatocellular carcinoma in a North American population: Does hepatobiliary MR imaging with Gd‐EOB‐DTPA improve sensitivity and confidence for diagnosis?

Purpose:

To evaluate the value of hepatobiliary phase imaging for detection and characterization of hepatocellular carcinoma (HCC) in liver MRI with Gd‐EOB‐DTPA, in a North American population.

Materials and Methods:

One hundred MRI examinations performed with the intravenous injection of Gd‐EOB‐DTPA in patients with cirrhosis were reviewed retrospectively. Nodules were classified as HCC (n = 70), indeterminate (n = 33), or benign (n = 22). Five readers independently reviewed each examination with and without hepatobiliary phase images (HBP). Lesion conspicuity scores were compared between the two readings. Lesion detection, confidence scores, and receiver operating characteristic (ROC) analysis were compared.

Results:

Lesion detection was slightly improved for all lesion types with the inclusion of the HBP, and was substantially higher for small HCCs (96.0% versus 85.3%). Mean confidence scores for the diagnosis of HCC increased for HCCs overall and each size category (P < 0.001). Diagnostic performance improved with the addition of the HBP (aggregate AROC 87.7% versus 80.0%, P < 0.01), and sensitivity for characterization improved (90.9% versus 78.3%, P < 0.01) while specificity was unchanged.

Conclusion:

Hepatobiliary phase imaging may improve small lesion detection (<1 cm) and characterization of lesions in general, in MRI of the cirrhotic liver with Gd‐EOB‐DTPA. J. Magn. Reson. Imaging 2013;37:398–406. © 2012 Wiley Periodicals, Inc.     

Peripheral low intensity sign in hepatic hemangioma: diagnostic pitfall in hepatobiliary phase of Gd-EOB-DTPA-enhanced MRI of the liver

Purpose:

To describe the presence of “peripheral low intensity sign” in hepatic hemangioma in the hepatobiliary phase (HP) of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd‐EOB‐DTPA)‐enhanced magnetic resonance imaging (MRI) and to compare the frequency of this sign between hepatic hemangiomas and hepatic metastases.

Materials and Methods:

The Institutional Review Board approved this study and waived the requirement for informed consent. Sixty‐four patients with 51 hepatic hemangiomas (n = 31 patients) and with 58 hepatic metastases (n = 33 patients) underwent Gd‐EOB‐DTPA‐enhanced MRI. In all hepatic hemangiomas, 41 lesions were the typical type and 10 were the high flow type. HP images were qualitatively evaluated for the frequency of peripheral low intensity sign in hepatic hemangiomas and hepatic metastases using a four‐point scale. Statistical evaluations were performed with a Mann–Whitney U‐test.

Results:

Peripheral low intensity signs were demonstrated in 24 (47%) of 51 hepatic hemangiomas, while they were seen in 27 (47%) of 58 hepatic metastases. There was no significant difference in the mean visual score of peripheral low intensity sign between all hepatic hemangiomas (0.84 ± 1.03) and hepatic metastases (0.76 ± 0.92). The mean visual score of peripheral low intensity sign in typical hemangiomas (1.02 ± 1.06) was significantly higher than that in high flow hemangiomas (0.10 ± 0.32) (P = 0.008).

Conclusion:

Peripheral low intensity sign is not specific for malignant tumors, and can be seen even in hepatic hemangiomas on HP of Gd‐EOB‐DTPA‐enhanced MRI. J. Magn. Reson. Imaging 2012;35:852–858. © 2011 Wiley Periodicals, Inc.     

Outcome of hypovascular hepatic nodules revealing no gadoxetic acid uptake in patients with chronic liver disease

Purpose:

To elucidate the natural history of hypovascular nodules that appear hypointense on hepatocyte‐phase gadoxetic acid‐enhanced MR images by focusing on hypervascularization over time.

Materials and Methods:

In this study, 135 hypovascular nodules revealing no gadoxetic acid uptake in 53 patients were examined. All nodules were retrospectively examined using serial follow‐up computed tomography (CT) and MRI examinations until hypervascularity was observed on arterial‐phase dynamic CT or gadoxetic acid‐enhanced MR images, or on CT during hepatic arteriography. Logistic regression analysis was used to investigate the association between hypervascularization and MR findings including a presence of fat assessed by a signal drop on opposed‐phase T1‐weighted images.

Results:

Of the 135 nodules, 16 underwent hypervascularization. The size of the nodules and the presence of fat in the nodules were independent indicators of hypervascularization. The 1‐year cumulative risk of hypervascularization was 15.6%. This risk was significantly increased in the case of nodules >10 mm (37.6%, P < 0.01) and fat‐containing nodules (26.5%, P < 0.01).

Conclusion:

Hypovascular nodules that appear hypointense on hepatocyte‐phase gadoxetic acid‐enhanced MR images may progress to conventional hypervascular hepatocellular carcinoma. Nodules more than 10 mm in diameter and containing fat are at high risk for developing hypervascularization. J. Magn. Reson. Imaging 2011;. © 2011 Wiley‐Liss, Inc.     

Usefulness of Gd‐EOB‐DTPA‐enhanced MR imaging in the evaluation of simple steatosis and nonalcoholic steatohepatitis

Purpose:

To evaluate the usefulness of gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd‐EOB‐DTPA)‐enhanced MR imaging (EOB‐MRI) in differentiating between simple steatosis and nonalcoholic steatohepatitis (NASH), as compared with MR in‐phase/out‐of‐phase imaging. The correlations between the MR features and histological characteristics were preliminarily investigated.

Materials and Methods:

From April 2008 to October 2011, 25 patients (13 simple steatosis and 12 NASH) who underwent both EOB‐MRI and in‐phase/out‐of‐phase imaging were analyzed. The hepatobiliary‐phase enhancement ratio and signal intensity loss on opposed‐phase T1‐weighted images (fat fraction) were compared between the simple steatosis and NASH groups. In the simple steatosis and NASH groups, the correlations between enhancement ratio and histological grade/stage were explored. In the NASH group, fat fraction was correlated with the steatosis score.

Results:

The enhancement ratio in NASH was significantly lower than that in simple steatosis (P = 0.03). In the simple steatosis and NASH groups, the enhancement ratio was significantly correlated with the fibrosis stage (r = ?0.469, P = 0.018). Fat fraction in NASH was strongly correlated with the steatosis score (r = 0.728, P = 0.007).

Conclusion:

In simple steatosis and NASH, the hepatobiliary‐phase enhancement ratio of EOB‐MRI showed significant association with fibrosis stage, and may be a useful discriminating parameter compared with the fat fraction measured by in‐phase/out‐of‐phase imaging. J. Magn. Reson. Imaging 2012;37:1137–1143. © 2012 Wiley Periodicals, Inc.

     

Assessment of liver function in thioacetamide‐induced rat acute liver injury using an empirical mathematical model and dynamic contrast‐enhanced MRI with Gd‐EOB‐DTPA

Purpose:

To evaluate thioacetamide (TAA)‐induced acute liver injury in rats using an empirical mathematical model (EMM) and dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI) with gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd‐EOB‐DTPA).

Materials and Methods:

Eighteen rats were divided into three groups (normal control [n = 6], TAA [140] [n = 6], and TAA [280] groups [n = 6]). The rats of the TAA (140) and TAA (280) groups were intravenously injected with 140 and 280 mg/kg body weight (BW) of TAA, respectively, while those of the normal control group were intravenously injected with the same volume of saline. DCE‐MRI studies were performed using Gd‐EOB‐DTPA (0.025 mmol Gd/kg; 0.1 mL/kg BW) as the contrast agent 48 hours after TAA or saline injection. After the DCE‐MRI study, blood was sampled and serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were measured. We calculated the rate of contrast uptake (α), the rate of contrast washout (β), the elimination half‐life of relative enhancement (RE) (T_1/2), the maximum RE (RE_max), and the time to (RE_max) (T_max) from time‐signal intensity curves using EMM.

Results:

The RE_max values in the TAA (140) groups and TAA (280) groups were significantly smaller than that in the normal control group. The T_max value in the TAA (280) group was significantly greater than that in the normal control group. The β value in the TAA (280) group was significantly smaller than those in the normal control and TAA (140) groups, whereas there were no significant differences in β among groups. The T_1/2 value in the TAA (280) group was significantly greater than those in the normal control and TAA (140) groups. The RE_max, T_max, β, and T_1/2 values significantly correlated with AST and ALT.

Conclusion:

The EMM is useful for evaluating TAA‐induced acute liver injury using DCE‐MRI with Gd‐EOB‐DTPA. J. Magn. Reson. Imaging 2012; 36:1483–1489. © 2012 Wiley Periodicals, Inc.     

Risk of hypervascularization in small hypovascular hepatic nodules showing hypointense in the hepatobiliary phase of gadoxetic acid-enhanced MRI in patients with chronic liver disease

Purpose

The purpose of this study was to elucidate the incidence and risk factors for the progression of hypointense nodules observed in the hepatobiliary phase of gadoxetic acid-enhanced magnetic resonance imaging (Gd-EOB-DTPA-enhanced MRI) of hypervascular hepatocellular carcinoma (HCC).

Materials and methods

Hypovascular nodules (112) showing hypointensity in the hepatobiliary phase of Gd-EOB-DTPA-enhanced MRI were examined in 54 patients. All patients underwent computed tomography during hepatic arteriography and computed tomography during arterial portography (CTAP) within a month after Gd-EOB-DTPA-enhanced MRI. According to the tumor size, 112 nodules were divided into two groups: those >10?mm in diameter (group A, n?=?39) and those ??10?mm in diameter (group B, n?=?73). The incidence of progression to hypervascular HCC was calculated using the Kaplan-Meier method.

Results

The incidence of hypervascularization was significantly higher in group A nodules than in group B nodules (p?<?0.0001). Tumor size (p?<?0.0001) and hypoattenuation in CTAP (p?=?0.0004) showed significant correlation with hypervascularization.

Conclusion

Hypointense nodules observed in the hepatobiliary phase of Gd-EOB-DTPA-enhanced MRI with diameters of >10?mm had a high probability of hypervascularization.     

Assessing liver function using dynamic Gd‐EOB‐DTPA‐enhanced MRI with a standard 5‐phase imaging protocol

Purpose:

To evaluate liver function obtained by tracer‐kinetic modeling of dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI) data acquired with a routine gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd‐EOB‐DTPA)‐enhanced protocol.

Materials and Methods:

Data were acquired from 25 cases of nonchronic liver disease and 94 cases of cirrhosis. DCE‐MRI was performed with a dose of 0.025 mmol/kg Gd‐EOB‐DTPA injected at 2 mL/sec. A 3D breath‐hold sequence acquired 5 volumes of 72 slices each: precontrast, double arterial phase, portal phase, and 4‐minute postcontrast. Regions of interest (ROIs) were selected semiautomatically in the aorta, portal vein, and whole liver on a middle slice. A constrained dual‐inlet two‐compartment uptake model was fitted to the ROI curves, producing three parameters: intracellular uptake rate (UR), extracellular volume (Ve), and arterial flow fraction (AFF).

Results:

Median UR dropped from 4.46 10^?2 min^?1 in the noncirrhosis to 3.20 in Child–Pugh A (P = 0.001), and again to 1.92 in Child–Pugh B (P < 0.0001). Median Ve dropped from 6.64 mL 100 mL^?1 in the noncirrhosis to 5.80 in Child–Pugh A (P = 0.01). Other combinations of Ve and AFF changes were not significant for any group.

Conclusion:

UR obtained from tracer kinetic analysis of a routine DCE‐MRI has the potential to become a novel index of liver function. J. Magn. Reson. Imaging 2013;37:1109–1114. © 2012 Wiley Periodicals, Inc.

     

Effect of isoflurane anesthesia and hypothermia on the hepatic kinetics of Gd-EOB-DTPA: evaluation using MRI of conscious mice

Purpose:

To develop a method for body magnetic resonance imaging (MRI) of conscious mice and investigate the effect of isoflurane anesthesia and hypothermia on the hepatic kinetics of gadoxetate disodium (Gd‐EOB‐DTPA).

Materials and Methods:

Conscious or anesthetized mice were restrained on a holder and the rectal temperature was measured serially. Serial MRI of the liver was performed after intravenous injection of Gd‐EOB‐DTPA with or without temperature control. Three mice were studied for each condition.

Results:

The temperature dropped rapidly in anesthetized mice beside the MR unit. The decline was less prominent in conscious mice. The temperature decreased less in anesthetized mice and remained constant in conscious mice in the radiofrequency (RF) coil. The washout of Gd‐EOB‐DTPA was slower in anesthetized hypothermic mice than in conscious normothermic mice. Warmed anesthetized mice showed faster washout, and cooled conscious mice showed delayed washout. Severer hypothermia in anesthetized mice resulted in weaker initial enhancement and slower washout.

Conclusion:

By separately manipulating the presence or absence of anesthesia and hypothermia, we demonstrated that washout of Gd‐EOB‐DTPA was delayed under hypothermia, regardless of anesthesia. Serial body MRI of conscious mice was feasible and allowed the evaluation of kinetics of a contrast agent, while excluding the possible effects of anesthesia. J. Magn. Reson. Imaging 2011;. © 2011 Wiley‐Liss, Inc.     

Prognosis of small hepatocellular nodules detected only at the hepatobiliary phase of Gd-EOB-DTPA-enhanced MR imaging as hypointensity in cirrhosis or chronic hepatitis

Purpose

To evaluate the prognosis of “strict” high-risk nodules (small hepatocellular nodules detected only in the hepatobiliary phase of initial Gd-EOB-DTPA-enhanced MR examination) in patients with cirrhosis or chronic hepatitis.

Methods and materials

The study included thirty-three patients with 60 “strict” high-risk nodules showing hypointensity at the hepatobiliary phase that was undetectable at the vascular phase and other conventional sequences of initial Gd-EOB-DTPA-enhanced MR imaging. These nodules were observed on follow-up MR examinations until hypervascularity was detected. The potential predictive factors for hypervascular transformation were compared between two groups (group A showing hypervascular transformation, group B not showing hypervascularization).

Results

Ten (16.7 %) of 60 “strict” high-risk nodules showed hypervascular transformation during follow-up periods (group A). The growth rates of the nodules in group A (6.3?±?4.5 mm/year) were significantly higher than those in group B (3.4?±?7.2 mm/year) (p?=?0.003). Additionally, the median observation period in group A (177.5?±?189.5 day) was significantly shorter than in group B (419?±?372.2 day) (p?=?0.045). The other predictive factors were not significantly correlated with hypervascularization.

Conclusions

Subsets of “strict” high-risk nodules showed hypervascular transformation during follow-up periods in association with increased growth rates, indicating that nodule growth rate is an important predictive factor for hypervascularization.

Key Points

? “Strict” high-risk nodules are defined as hepatocellular nodules detected only in the hepatobiliary-phase. ? Subsets of “strict” high-risk nodules showed hypervascular transformation during follow-up periods. ? Increased growth rate is an important predictive factor for hypervascular transformation. ? Management of patients with “strict” high-risk nodules becomes more appropriate.     

Detectability of hepatocellular carcinoma by gadoxetate disodium‐enhanced hepatic MRI: Tumor‐by‐tumor analysis in explant livers

Purpose:

To investigate the detectability of hepatocellular carcinoma (HCC) on Gd‐EOB‐enhanced MR images (Gd‐EOB‐MRI), we performed tumor‐by‐tumor analysis of pathologically confirmed tumors using explants from cirrhotic patients who had undergone liver transplantation.

Materials and Methods:

We studied 11 explanted livers and classified the tumor intensity during the arterial phase (AP) and the hepatobiliary phase (HBP) as low in HBP with early enhancement (EE) in AP (A), as high in HBP with EE in AP (B), as low in HBP without EE in AP (C), as high in HBP without EE in AP (D), and as iso‐intense in HBP with EE in AP (E). The diagnostic criteria for HCC were (i) pattern A and C, (ii) pattern A and E, (iii) pattern C and E, and (iv) patterns A, C, and E.

Results:

Of the 71 HCCs, 22 were not detected at MRI; of these, 9 were moderately differentiated and 13 were well‐differentiated HCCs. The sensitivity of Gd‐EOB‐MRI for diagnostic criteria 1, 2, 3, and 4 was 63.4%, 52.1%, 22.5%, and 69.0%.

Conclusion:

The maximum sensitivity of Gd‐EOB‐MRI for HCC was only 69.0% even when diagnostic criteria that included all previously reported HCC patterns were adopted. J. Magn. Reson. Imaging 2013;37:684—691. © 2012 Wiley Perioidicals, Inc.     

Gd‐EOB‐DTPA‐enhanced MR imaging: Prediction of hepatic fibrosis stages using liver contrast enhancement index and liver‐to‐spleen volumetric ratio

Purpose:

To develop and evaluate a quantitative parameter for staging hepatic fibrosis by contrast enhancement signal intensity and morphological measurements from gadoxetic acid (Gd‐EOB‐DTPA)‐enhanced MR imaging.

Materials and Methods:

MR images were obtained in 93 patients; 75 patients had histopathologically proven hepatic fibrosis and 18 patients who had healthy livers were evaluated. The liver‐to‐muscle signal intensity ratio (SI_post = SIliver/SImuscle), contrast enhancement index (CEI = SIpost/SIpre), and liver‐to‐spleen volumetric ratio (VR = Vliver/Vspleen) were evaluated for staging hepatic fibrosis.

Results:

VR was most strongly correlated with fibrosis stage (7.21; r = ?0.83; P < 0.001). Sensitivity, specificity, and area under the ROC curve demonstrated by linear regression formula generated by VR and CEI in predicting fibrous scores were 100%, 73%, and 0.91, respectively, for the detection of hepatic fibrosis F1 or greater (≥ F1),100%, 87%, and 0.96 for ≥ F2, 74%, 98%, and 0.93 for ≥ F3 and 91%, 100%, and 0.97 for F4.

Conclusion:

The liver‐to‐spleen volumetric ratio and contrast enhancement index were reliable biomarkers for the staging of hepatic fibrosis on Gd‐EOB‐DTPA‐enhanced MR imaging. J. Magn. Reson. Imaging 2012;36:1148–1153. © 2012 Wiley Periodicals, Inc.