Application of Reduced-FOV Diffusion-Weighted Imaging in Evaluation of Normal Pituitary Glands and Pituitary Macroadenomas.

BACKGROUND AND PURPOSE: FOV optimized and constrained undistorted single-shot imaging provides relatively high-resolution images with few artifacts. This study evaluated the image quality and value of FOV optimized and constrained undistorted single-shot DWI in the evaluation of normal pituitary glands and pituitary macroadenomas.

MATERIALS AND

METHODS

Subjects with normal pituitary glands and patients with pituitary macroadenomas underwent FOV optimized and constrained undistorted single-shot and EPI DWI. Two neuroradiologists graded the image quality based on visualization of the pituitary stalk, pituitary gland, and pituitary macroadenoma. Intra- and interobserver agreements were assessed by κ statistics. Image quality and ADCs were compared between the 2 methods by the paired Wilcoxon signed rank test and t test. Differences in ADC between normal pituitary glands and macroadenomas were analyzed by the independent-samples t test.

RESULTS

Twenty-eight subjects with normal pituitary glands and 16 patients with macroadenomas were enrolled. Intra- and interobserver agreements for image-quality assessment were moderate to substantial. Relative to EPI DWI, FOV optimized and constrained undistorted single-shot DWI exhibited obviously better image quality both in normal pituitary glands and macroadenomas. There was no significant difference in ADCs of macroadenomas between the 2 methods. Macroadenomas with soft consistency (0.75 ± 0.14 × 10-3 mm2/s) had significantly lower mean ADC than normal pituitary glands (1.18 ± 0.19 × 10-3 mm2/s; P < .001).

CONCLUSIONS

FOV optimized and constrained undistorted single-shot DWI helps acquire high-resolution images of normal pituitary glands and pituitary macroadenomas with relatively few susceptibility artifacts in a clinically feasible scan time. This sequence might be helpful for evaluating the consistency of pituitary macroadenomas.