DYNAMIC AND CONVENTIONAL SPIN-ECHO MR OF PITUITARY MICROLESIONS

PURPOSE: To determine whether dynamic traditional spin-echo MR imaging , with the use of routine T1 parameters during contrast infusion, is s uperior to standard MR imaging after contrast administration for detec ting microlesions of the pituitary gland. METHODS: Sixty-four patients with pituitary microlesions 3 to 10 mm in diameter were examined with a dynamic traditional spin-echo technique; that is, a typical T1 spin -echo sequence of 500-600/20-25/2 (repetition time/echo time/excitatio ns), 3-mm-thick sections, 16-cm field of view, 256 x 128 matrix, and a scan time ranging from 2 minutes to 2 minutes 40 seconds during contr ast infusion. In addition, standard imaging with unenhanced and contra st-enhanced spin-echo sequences were obtained. The three sequences wer e evaluated retrospectively and graded for gland-lesion contrast consp icuity, lesion homogeneity, and delineation of lesion margin. RESULTS: The dynamic sequence was judged to be better than the standard enhanc ed sequence for depicting microlesions in 42% to 47% of patients. Lesi ons were identified only on the dynamic study in an additional 11% to 14% of patients. Lesions were seen equally well on the standard and dy namic sequences only in 16% to 23% of cases. The standard postcontrast sequence was judged better in 12.5% to 17% of cases, with lesions ide ntified only on the standard sequence in an additional 8% to 9%. CONCL USION: Dynamic traditional spin-echo MR imaging improved lesion detect ion and provided increased clarity over standard sequences after contr ast infusion. Both sequences are important, since lesions were detecte d only on the dynamic sequence in 11% to 14% of patients and only on t he standard sequence in 8% to 9% of patients.