Abstract

Purpose: To assess the feasibility of three-dimensional fat-suppressed T1-weighted gradient-echo sequence with radial volumetric interpolated breath-hold examination (rVIBE) compared with that of conventional Cartesian VIBE (cVIBE) sequence for free-breathing hepatobiliary phase of gadolinium-ethoxybenzyl-diethylenetriaminepentaacetic acid (Gd-EOB-DTPA)-enhanced MR imaging and to investigate the optimal number of radial views for rVIBE.

Methods: Thirty patients who underwent hepatobiliary phase Gd-EOB-DTPA-enhanced MR imaging with freebreathing cVIBE and rVIBE sequences using radial views of 256 (rVIBE₂₅₆), 512 (rVIBE₅₁₂), and 1024 (rVIBE₁₀₂₄) for the evaluation of suspected liver tumors were enrolled in our study. Signal-to-noise ratios (SNRs) of the liver and image quality were compared between cVIBE and rVIBE sequences using the Steel-Dwass test of post hoc nonparametric multiple comparisons.

Results: SNR of the liver was significantly higher for rVIBE with all three radial views than for cVIBE (all, P<0.001). The rVIBE₂₅₆ showed a significantly lower SNR than rVIBE₅₁₂ (P=0.004) and rVIBE₁₀₂₄ (P<0.001), but no significant difference was obtained between rVIBE₅₁₂ and rVIBE₁₀₂₄ (P=0.122). The overall image quality was significantly higher for all rVIBE radial views than for cVIBE (all, P<0.001). The mean score of overall image quality was significantly lower for rVIBE₂₅₆ than for rVIBE₅₁₂ and rVIBE₁₀₂₄ (both, P<0.001), and there was no significant difference between rVIBE₅₁₂ and rVIBE₁₀₂₄ (P=0.902).

Conclusions: Our study suggests that rVIBE₅₁₂ is more feasible in patients with diminished respiratory capacity in the hepatobiliary phase of Gd-EOB-DTPA-enhanced MR imaging.

Keywords: Liver; Free-breathing abdominal MRI; Radial k-space sampling; Three-dimensional gradient echo-sequence; Gadoxetic acid- DTPA (Gd-EOB-DTPA)