Evaluation of hemodynamic imaging findings of hypervascular hepatocellular carcinoma: comparison between dynamic contrast-enhanced magnetic resonance imaging using radial volumetric imaging breath-hold examination with k-space-weighted image contrast reconstruction and dynamic computed tomography during hepatic arteriography

The peritumoral hypointense rim around hepatocellular carcinoma on T2*-weighted magnetic resonance imaging: radiologic-pathologic correlation

Background

A peritumoral hypointense rim (PTHR) is sometimes observed around hepatocellular carcinoma (HCC) on T2*-weighted images (T2*WIs). We aimed to investigate the association between the PTHR and histopathologic findings on T2*WIs.

Methods

We assessed the presence of a PTHR on T2*WIs in 39 pathologically proven HCCs from April 2012 to December 2013. Prussian blue staining was performed, and iron deposition was evaluated by semiquantitative and quantitative methods. Optical density was used in the quantitative methods. The associations between a PTHR on T2*WI and histopathologic peritumoral or background liver iron deposition were analyzed.

Results

A PTHR on T2*WI was observed in 23 of 39 (59%) HCCs. There was no significant difference in the histopathologic fibrous capsule findings (P = 0.394). In the semiquantitative methods, both peritumoral and background liver iron deposition grade were significantly higher in HCCs with a PTHR compared with HCCs without a PTHR (P < 0.001). The mean optical density in HCCs with a PTHR was significantly higher compared with HCCs without a PTHR, in the quantitative peritumoral (42,244.1 ± 20,854.9 vs. 18,739.1 ± 12,258.7, respectively; P < 0.001) and background liver iron deposition analyses (35,554.7 ± 19,854.8 vs. 17,292.4 ± 11,605.8, respectively; P < 0.001). Tumor size (P = 0.005), etiology (P = 0.001), and degree of fibrosis (P = 0.042) were significantly associated with the presence of a PTHR.

Conclusions

A PTHR in HCCs on T2*WIs was strongly associated with peritumoral iron deposition in the iron-deposited background liver but not with the fibrous capsule.

Utility of Stack-of-stars Acquisition for Hepatobiliary Phase Imaging without Breath-holding

Purpose:

Post-contrast liver magnetic resonance imaging is typically performed with breath-hold 3D gradient echo sequences. However, breath-holding for >10 s is difficult for some patients. In this study, we compared the quality of hepatobiliary phase (HBP) imaging without breath-holding using the prototype pulse sequences stack-of-stars liver acquisition with volume acceleration (LAVA) (LAVA Star) with or without navigator echoes (LAVA Star_navi+ and LAVA Star_navi−) and Cartesian LAVA with navigator echoes (Cartesian LAVA_navi+).

Methods:

Seventy-two patients were included in this single-center, retrospective, cross-sectional study. HBP imaging using the three LAVA sequences (Cartesian LAVA_navi+, LAVA Star_navi−, and LAVA Star_navi+) without breath-holding was performed for all patients using a 3T magnetic resonance system. Two independent radiologists qualitatively analyzed (overall image quality, liver edge sharpness, hepatic vein clarity, streak artifacts, and respiratory motion/pulsation artifacts) HBP images taken by the three sequences using a five-point scale. Quantitative evaluations were also performed by calculating the liver-to-spleen, -lesion, and -portal vein (PV) signal intensity ratios. The results were compared between the three sequences using the Friedman test.

Results:

LAVA Star_navi+ showed the best image quality and hepatic vein clarity (P < 0.0001). LAVA Star_navi− showed the lowest image quality (P < 0.0001–0.0106). LAVA Star_navi+ images showed fewer streak artifacts than LAVA Star_navi− images (P < 0.0001), while Cartesian LAVA_navi+ images showed no streak artifacts. Cartesian LAVA_navi+ images showed stronger respiratory motion/pulsation artifacts than the others (P < 0.0001). LAVA Star_navi− images showed the highest liver-to-spleen ratios (P < 0.0001–0.0005). Cartesian LAVA_navi+ images showed the lowest liver-to-lesion and -PV ratios (P < 0.0001–0.0108).

Conclusion:

In terms of image quality, the combination of stack-of-stars acquisition and navigator echoes is the best for HBP imaging without breath-holding.