Comparison of True FISP with Turbo SE in Ovarian Imaging

Abstract

Purpose: To compare the signal pattern of True FISP (true fast imaging with steady state precession) with that of T 2 -weighted TSE (turbo spin echo) sequencing in several ovarian pathologies and to clarify the pathologies that may be misdiagnosed when True FISP is used as a fast T 2 -weighted MR (magnetic resonance) imaging technique.Methods: A total of 56 patients with 58 ovarian lesions were prospectively studied. The histopathological diagnoses were surgically conˆrmed in all patients. All MR images were acquired with a 1.5T MR scanner. After routine MR examination (T 2 -weighted sagittal imaging with a turbo spin echo sequence and T 1 and T 2 transverse imaging with a spin echo and turbo spin echo sequence, respectively), True FISP was performed in the sagittal plane with a fat-saturation technique. The acquisition times for the True FISP and TSE techniques were 27 s and 4 min, 42 s, respectively. Three radiologists interpreted all images according to three grading scores and with particular reference to the diŠerence in signal pattern between the two sequences (1＝similar signal patterns in the ovarian lesions in both True FISP and TSE images; 2＝partially diŠerent signal patterns in both True FISP and TSE images; and 3＝con‰icting signal patterns in both True FISP and TSE images).Results: Those assigned a score of``1'' included 30 patients with 30 ovarian lesions (12 malignant lesions and 18 benign lesions); those assigned a score of``2'' included 10 patients with 10 lesions (two malignant and eight benign); and those assigned a score of`3 '' included 16 patients with 18 ovarian lesions (two malignant and 16 benign). With the in‰uence of the fat-suppression technique excluded, eight ovarian lesions showed con‰icting signal patterns between the two sequences and high signal intensity of hemorrhaging in the corresponding lesion in T 1 -weighted images. Lesions of both high and low signal intensity in TSE images appeared as lesions of high signal intensity in True FISP images. About 14z (8 W 56 lesions) of the True FISP and TSE signal patterns in ovarian pathology were con‰icting in this study.Conclusion: The results indicate that the True FISP technique cannot replace the T 2 -weighted TSE technique in the evaluation of ovarian pathology. T 1 -weighted images with or without fat suppression are required for the evaluation of ovarian lesions with FISP images.