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.     

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.     

Can MR fluoroscopic triggering technique and slow rate injection provide appropriate arterial phase images with reducing artifacts on gadoxetic acid‐DTPA (Gd‐EOB‐DTPA)‐enhanced hepatic MR imaging?

Purpose:

To evaluate whether using MR fluoroscopic triggering technique and slow rate injection improves the quality of arterial phase images in gadoxetic acid‐DTPA‐enhanced (Gd‐EOB‐DTPA) MR imaging because of proper acquisition timing and reduction of artifacts.

Materials and Methods:

Two hundred sixteen patients undergoing examination for liver diseases were retrospectively reviewed. All MR images were obtained with two Gd‐EOB‐DTPA injection protocols: (i) a combination protocol, in which the MR fluoroscopic triggering technique and slow rate injection (1 mL/s) were used; and for comparison, (ii) a conventional protocol, in which adjusted fixed scan delay and ordinary rate injection (2 mL/s) were adopted. Signal‐to‐noise ratio (SNR) of aorta, portal vein, and liver parenchyma on arterial phase images were calculated. Two blinded readers independently evaluated the obtained arterial phase images in terms of acquisition timing and degree of artifacts.

Results:

The SNRs of aorta and portal vein on arterial phase images were significantly higher in the combination protocol group (aorta/portal: 221.9 ± 91.9/197.1 ± 89.8) than that in the conventional protocol group (aorta/portal: 169.8 ± 97.4/92.7 ± 48.5) (P < 0.05). The acquisition timing for arterial phase images with the combination protocol was significantly better than that with the conventional protocol (P < 0.01). The image quality of the combination protocol was significantly higher than that of the conventional protocol (P < 0.01). The occurrence rate of moderate or severe degree of artifacts in the conventional protocol (38.0%) was more prominent than that in the combination protocol (18.5%).

Conclusion:

The combination of the MR fluoroscopic triggering technique and slow rate injection provides proper arterial phase images and reduces the artifacts in Gd‐EOB‐DTPA MR imaging. J. Magn. Reson. Imaging 2010;32:334–340. © 2010 Wiley‐Liss, Inc.     

Liver MRI in the hepatocyte phase with gadolinium‐EOB‐DTPA: Does increasing the flip angle improve conspicuity and detection rate of hypointense lesions?

Purpose:

To compare conspicuity and detection rate of hypointense lesions on T1‐weighted (T1w) gradient echo (GRE) sequences with low and high flip angles (FA) in hepatocyte phase magnetic resonance imaging (MRI) using gadoxetate disodium.

Materials and Methods:

This Health Insurance Portability and Accountability Act (HIPAA)‐compliant study was Institutional Review Board (IRB)‐approved. The study population consisted of patients with hypointense liver lesions undergoing MRI with gadoxetate disodium, with hepatocyte‐phase fat suppressed 3D T1w GRE sequences at both low (10–12°) and high (30–35°) FA. Contrast‐to‐noise ratios (CNRs) were calculated for liver parenchyma vs. large lesions and common bile duct (CBD) vs. liver. Three radiologists each assigned a conspicuity score (CS) for each lesion detected at low or high FA. Paired Student's t‐tests compared the lesion detection (LD) rate using only the hepatocyte phase data set compared with the entire MRI examination, and CS for low and high FA.

Results:

In all, 57 large and 70 small lesions were identified in 18 patients. Average LD and CS were significantly greater at high FA versus low FA overall (LD 89.0% vs. 79.5%; CS 2.8 vs. 2.2; P < 0.05) and for small lesions (81.4% vs. 65.7%; 2.5 vs. 1.8; P < 0.05). Average liver‐to‐lesion CNR for large lesions and CBD‐to‐liver CNR was significantly greater at high FA (P < 0.05).

Conclusion:

Increasing the FA in hepatocyte phase MRI with gadoxetate disodium improves hypointense lesion detection and conspicuity, particularly for small lesions. J. Magn. Reson. Imaging 2012;35:611‐616. © 2011 Wiley Periodicals, Inc.