Examining a canine model of stunned myocardium with Gd-DTPA-enhanced MRI.

It has previously been shown that the distribution volume of Gd-DTPA (lambda) in infarcted, canine myocardium is higher than that of normal tissue. The purpose of this study was to determine whether stunned myocardium exhibits increased lambda. Stunning was produced in beagles by means of 30 min LAD occlusion followed by 3 weeks (n = 4) reperfusion. Gd-DTPA was infused at each imaging session and lambda determined in vivo using a saturation recovery turboFLASH sequence; cine imaging was used to assess ventricular wall thickening (%WT). (201)Tl uptake was used as an independent assessment of viability. %WT data confirmed that the brief insult caused prolonged, yet reversible, regional contractile dysfunction in each animal. %WT was not significantly different from baseline values by 3 weeks post-reflow. Normal (201)Tl uptake confirmed the absence of infarction. The lambda of stunned tissue (lambda = 0.381 +/- 0.030 ml/g) was not elevated above that of normal tissue (lambda = 0.398 +/- 0.027 ml/g, P = NS), at any time point studied, in vivo. These data suggest that an increase in lambda is a specific indicator of irreversible damage.     

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.     

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.

     

Differentiating combined hepatocellular and cholangiocarcinoma from mass-forming intrahepatic cholangiocarcinoma using gadoxetic acid-enhanced MRI

Purpose:

To examine the differential features of combined hepatocellular and cholangiocarcinoma (HCC‐CC) from mass‐forming intrahepatic cholangiocarcinoma (ICC) on gadoxetic acid‐enhanced MRI.

Materials and Methods:

Forty patients with pathologically proven combined HCC‐CC (n = 20) and ICCs (n = 20) who had undergone gadoxetic acid‐enhanced MRI were enrolled in this study. MR images were analyzed for the shape of lesions, hypo‐ or hyperintense areas on the T2‐weighted image (T2WI), rim enhancement during early dynamic phases, and central enhancement with hypointense rim (target appearance) on the 10‐min and 20‐min hepatobiliary phase (HBP). The significance of these findings was determined by the χ² test.

Results:

Irregular shape and strong rim enhancement during early dynamic phases, and absence of target appearance on HBP favored combined HCC‐CCs (P < 0.05). Lobulated shape, weak peripheral rim enhancement, and the presence of complete target appearance on the 10‐min and 20‐min HBP favored ICCs (P < 0.05). However, 10 CC‐predominant type of combined HCC‐CC showed complete or partial target appearance on 10‐min HBP.

Conclusion:

The shape of tumors, degree of rim enhancement during early dynamic phases, and target appearance on HBP were valuable for differentiating between combined HCC‐CC and mass‐forming ICC on gadoxetic acid‐enhanced MRI. J. Magn. Reson. Imaging 2012;36:881–889. © 2012 Wiley Periodicals, 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.     

Assessment of fast dynamic imaging and the use of Gd‐EOB‐DTPA for MR‐guided liver interventions

Purpose:

1) To analyze and compare fast dynamic imaging sequences to biopsy suspect liver lesions. 2) To evaluate the additional use of hepatocyte‐specific contrast agent compared to the nonenhanced fast dynamic scans and diagnostic liver imaging.

Materials and Methods:

Image acquisition was performed using a 1T open‐configured scanner suitable for interventional purposes. Transversal postcontrast T1‐weighted (T1w) fat‐saturated 3D high‐resolution examination (THRIVE) images were acquired >20 minutes postintravenous application of gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd‐EOB‐DTPA). A single slice, crossing the level of the lesion, was acquired using intermediate‐weighted steady‐state free‐precession (bTFE), T1w‐gradient echo and spin echo (T1FFE/TSE), T2w‐spin echo (sshTSE) sequences. T1w imaging was acquired prior and after contrast media application. Diagnostic and fast dynamic images were compared based on a 10‐point rating scale. In addition, the liver‐to‐lesion‐contrast ratio was measured.

Results:

A total of 39 malignant lesions with a mean diameter of 13 mm (5–30 mm) in 39 patients were included. Concerning a test of noninferiority, there was no significant difference between rating score values of fast dynamic imaging employing contrast‐enhanced T1FFE‐sequences compared to diagnostic THRIVE (P = 0.001). Calculated liver‐to‐lesion contrast also showed no difference for either imaging sequence (P = 1.0). All other sequences tested showed significant inferiority (P ≤ 0.001).

Conclusion:

T1w Gd‐EOB‐DTPA contrast‐enhanced fast dynamic GRE imaging significantly improves the contrast behavior of malignant liver lesions comparable to diagnostic imaging and is best suited for liver intervention, especially at 1T open magnetic resonance imaging. J. Magn. Reson. Imaging 2011;. © 2011 Wiley‐Liss, Inc.     

Simple Method for evaluating the degree of liver parenchymal enhancement in the hepatobiliary phase of gadoxetic acid‐enhanced magnetic resonance imaging

Purpose:

To establish a simple method to evaluate the degree of liver parenchymal enhancement in the hepatobiliary phase (HP) of gadoxetic acid‐enhanced magnetic resonance imaging (MRI).

Materials and Methods:

Subjects comprised 75 patients with or without chronic liver disease who underwent gadoxetic acid‐enhanced MRI and indocyanine green retention at 15 minutes (ICG‐R15). HP images were used for data analysis. In the quantitative evaluation, liver‐to‐phantom signal intensity (SI) ratio (LPR), liver‐to‐portal vein SI ratio (LPVR), and liver‐to‐kidney SI ratio (LKR) were calculated. In qualitative visual assessment, liver‐to‐portal vein contrast (LPVC) and liver‐to‐kidney contrast (LKC) were assessed using a 5‐point scale (1, hyperintense; 2, slightly hyperintense; 3, isointense; 4, slightly hypointense; 5, hypointense). Statistical evaluations included the Spearman's rank correlation test.

Results:

LPVC and LKC correlated significantly with LPR (ρ = ?0.445, P < 0.001; ρ = ?0.576, P < 0.001, respectively). LPVC and LKC showed significant correlations with LPVR and LKR (ρ = ?0.659, P < 0.001; ρ = ?0.674, P < 0.001, respectively). In addition, LPVC and LKC correlated significantly with ICG‐R15 (ρ = 0.696, P < 0.001; ρ = 0.795, P < 0.001, respectively).

Conclusion:

LPVC and LKC can be used as simple visual indicators to objectively assess the degree of liver parenchymal enhancement on HP of gadoxetic acid‐enhanced MRI. J. Magn. Reson. Imaging 2013;37:1115–1121. © 2012 Wiley Periodicals, Inc.

     

Relationship between signal intensity on hepatobiliary phase of gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA)-enhanced MR imaging and prognosis of borderline lesions of hepatocellular carcinoma

Purpose

To elucidate the incidence of signal intensity patterns of borderline lesions of hepatocellular carcinoma (HCC) on hepatobiliary phase Gd-EOB-DTPA (EOB) enhanced MRI and clarify the natural histories of these lesions.

Materials and methods

Total 99 borderline lesions of HCC were identified by angiography-assisted CT. The signal intensity of borderline lesions on hepatobiliary phase of EOB-enhanced MRI was analyzed. Progress rate from borderline lesions to hypervascular HCC was calculated with the Kaplan–Meier method among each signal intensity groups of nodules.

Results

On hepatobiliary phase of EOB-enhanced MRI, 41.4% of the borderline lesions showed hypo-, 42.4% showed iso-, and 16.2% showed hyperintense, compared to background liver. Overall progress rates from borderline lesions to HCC were 10% in 1-year, 14% in 2-year and 20% in 3-year follow-up period. Progress rates to HCC in hypointense borderline lesions were 17% in 1-year, 28% in 2-year and 41% in 3-year follow-up period, and in isointense borderline lesions were 7% in 1-year, 7% in 2-year and 7% in 3-year follow-up period. No hyperintense borderline lesions progressed to HCC in follow-up period.

Conclusion

Although borderline lesions of HCC may show hypo-, iso- and hyperintensity on hepatobiliary phase of EOB-enhanced MRI, hypointense borderline lesions are high risk to progress HCC.     

MR prediction of liver fibrosis using a liver-specific contrast agent: Superparamagnetic iron oxide versus Gd-EOB-DTPA

Purpose:

To examine whether the uptake of a liver‐specific contrast agent in the liver parenchyma was correlated with the degree of liver fibrosis.

Materials and Methods:

This retrospective study included 54 and 63 patients who underwent superparamagnetic iron oxide (SPIO)‐ and gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd‐EOB‐DTPA)‐enhanced MRI before liver surgery, respectively. For each patient, we calculated ΔR2* and ΔR2, which represent differences in R2* and R2 values of the liver parenchyma before and after administration of SPIO; and the increase rate of liver‐to‐spleen signal intensity ratio (LSR) on the hepatobiliary phase compared with the precontrast image. The correlation of each MR parameter with the degree of liver fibrosis (F0 to F4) was assessed using Spearman's rank correlation test.

Results:

The increase rate of LSR was best correlated with the degree of liver fibrosis and significantly decreased as the liver fibrosis progressed (rho = ?0.641; P < 0.0001). It showed sensitivity of 76.9% and specificity of 83.3% in differentiating F3 or greater fibrosis when 1.126 or less was set up as a cut‐off value. No significant correlation was obtained between ΔR2* or ΔR2 and the degree of liver fibrosis.

Conclusion:

The uptake of Gd‐EOB‐DTPA in the liver parenchyma decreased as the liver fibrosis progressed. J. Magn. Reson. Imaging 2012;36:664–671. © 2012 Wiley Periodicals, Inc.

     

Optimal scanning protocol of arterial dominant phase for hypervascular hepatocellular carcinoma with gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced MR

Purpose:

To investigate optimal delay time of hepatic arterial phase in Gadoxetate‐enhanced MR for detecting hypervascular hepatocellular carcinoma (HCC).

Materials and Methods:

Forty‐five patients with 85 hypervascular HCCs and 9 patients with 16 hypervascular HCCs underwent Gadoxetate‐ and Gd‐DTPA‐enhanced MR at 1.5 Tesla (T) system, respectively. All HCCs were analyzed 10–38 s after injection using a time‐resolved dynamic MR sequence with keyhole data sampling. Seven sequential phase images (1 phase = 4 s) were obtained during a single breath hold of 28 s. Time–intensity curves of the abdominal aorta, liver parenchyma, and HCC were obtained, then aortic contrast arrival time, time of peak HCC enhancement, duration time of HCC and aortic enhancement, and time delay from aortic contrast arrival to peak enhancement of HCC were measured.

Results:

Aortic contrast arrival time was 15.1 ± 2.9 s, time of peak HCC enhancement 29.9 ± 4.6 s, duration time of HCC enhancement 17.4 ± 6.4 s postinjection of Gadoxetate. Duration of aortic enhancement (23.6 ± 3.5 s) of Gadoxetate‐enhanced MR was significantly less than that of Gd‐DTPA‐enhanced MR (26.3 ± 2.8 s) (P < 0.0059).

Conclusion:

Peak enhancement time of HCC on Gadoxetate‐enhanced MR imaging occurred at 14.6 ± 4.6 s after aortic contrast arrival. J. Magn. Reson. Imaging 2011;33:864–872. © 2011 Wiley‐Liss, 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.

     

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.