Contrast-Enhanced Three-Dimensional MR Imaging Using a Volumetric Interpolated Breath-hold Examination (VIBE): Clinical Utility in the Evaluation of Renal Tumors

Lee, Young Hwan; Lee, Jeong Min; Kim, Chong Soo

Abstract

PURPOSE
To compare, in terms of technical feasibility, image quality and clinical efficacy, contrast-enhanced three-dimensional (3D) MR imaging using volumetric interpolated breath-hold examination (VIBE) with twodimensional gradient-echo MR imaging for the evaluation of renal masses.
MATERIALS AND METHODS
Twenty-three patients with 25 renal masses underwent dynamic MR imaging using a 1.5-T MR system and the 3D VIBE, 2D fast low angle shot (FLASH), and combined fat saturation techniques after the injection of 20 ml of Gd-DTPA. We compared postcontrast 2D FLASH and 3D VIBE images with precontrast 2D FLASH images. For quantitative analysis, the signal-to-noise and lesion to kidney contrast-to-noise ratio of the images were calculated using the three different techniques. For qualitative analysis, two experienced radiologists analyzed the images in terms of artifacts, lesion conspicuity and delineation, and general image quality. Delineation of the anatomy of renal vasculature and pelvocalyceal systems on reconstructed 3D VIBE MIP images was also assessed.
RESULTS
Quantitative analysis showed that the SNR of a renal mass was slightly higher at postcontrast 2D FLASH than at 3D VIBE imaging, and the SNR of renal cortex was higher at 3D VIBE than at postcontrast 2D FLASH imaging. The differences were, though, statistically insignificant (p>0.05). The CNR of a renal mass was, however, significantly higher at 3D VIBE than at 2D FLASH imaging (p<0.05). Qualitative analysis showed that general image quality was best at postcontrast 3D VIBE, followed by 2D FLASH and precontrast 2D FLASH imaging, and image artifacts were worst at post-contrast 2D FLASH image (p<0.05). In terms of lesion conspicuity and delineation, 3D VIBE gave the best results and postcontrast images were better than precontrast (p<0.05). Reconstructed angiographic and urographic images using the VIBE technique provided information about the anatomy of the renal vasculature and pelvocalyceal system.
CONCLUSION
3D VIBE MR imaging offers comparable or superior image quality to 2D FLASH, and because it can provide angiograms and urograms may be more useful in the staging work-up of renal malignancies.