Comparison of true FISP with turbo SE in ovarian imaging.
OBJECTIVE
To compare the signal pattern of True FISP (true fast imaging with steady state precession) with that of T2-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 T2-weighted MR (magnetic resonance) imaging technique.


METHODS
A total of 56 patients with 58 ovarian lesions were prospectively studied. The histopathological diagnoses were surgically confirmed in all patients. All MR images were acquired with a 1.5T MR scanner. After routine MR examination (T2-weighted sagittal imaging with a turbo spin echo sequence and T1 and T2 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 difference in signal pattern between the two sequences (1=similar signal patterns in the ovarian lesions in both True FISP and TSE images; 2=partially different signal patterns in both True FISP and TSE images; and 3=conflicting 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 influence of the fat-suppression technique excluded, eight ovarian lesions showed conflicting signal patterns between the two sequences and high signal intensity of hemorrhaging in the corresponding lesion in T1-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 14% (8/56 lesions) of the True FISP and TSE signal patterns in ovarian pathology were conflicting in this study.


CONCLUSIONS
The results indicate that the True FISP technique cannot replace the T2-weighted TSE technique in the evaluation of ovarian pathology. T1-weighted images with or without fat suppression are required for the evaluation of ovarian lesions with FISP images.
Hori
Masaaki
M
Department of Radiology, University of Yamanashi, Japan. masahori-tky@umin.ac.jp
Ichikawa
Tomoaki
T
Sano
Katsuhiro
K
Araki
Tsutomu
T
Kasai
Kazunori
K
Ashizawa
Masato
M
Kuwamoto
Kazuhiko
K
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D010051:Ovarian Neoplasms / Q000473:pathology*; D011446:Prospective Studies