Fibroma and fibrothecoma of the ovary: MR imaging findings.

PURPOSE: To describe the morphologic and signal intensity characteristics on magnetic resonance (MR) images of fibromas and fibrothecomas. MATERIALS AND METHODS: MR images of 11 female patients with histologically proved fibromas or fibrothecomas were reviewed, and morphologic and signal intensity characteristics of the lesions were analyzed. MR imaging findings were correlated with histologic findings. RESULTS: All fibromas and fibrothecomas showed homogeneous low signal intensity on T1-weighted images. On T2-weighted images, the two smallest lesions showed homogeneous low signal intensity, and eight of the other nine lesions showed predominantly low signal intensity. Edema was noted only in larger lesions, and cystic degeneration was noted only in three of the largest lesions. On T2-weighted images, the percentage of low signal intensity in the lesion was not found to be related to lesion size, and the percentage of low signal intensity in fibromas was not significantly different from that in fibrothecomas (P = .55). Many lesions showed heterogeneous signal intensity; the solid component was distributed peripherally, and the cystic component was located centrally or eccentrically. Free intraperitoneal fluid was noted in 10 of 11 lesions and was not significantly correlated with lesion size (r = .52 and P = .10). CONCLUSION: Because of their predominantly low signal intensity on T2-weighted images, fibromas and fibrothecomas display a relatively specific appearance on MR images.

Can running cause the appearance of marrow edema on MR images of the foot and ankle?

PURPOSE: To determine if runners have an increased prevalence of marrow edema in the foot and ankle compared with nonrunners at magnetic resonance (MR) imaging. MATERIALS AND METHODS: Ankles and feet were imaged in 20 runners and 12 nonrunners with a fast short inversion time inversion-recovery sequence at 1.5 T. Edema within each bone was graded from 0 (no edema) to 3 (severe edema). Total scores for each subject equaled the sum of the grades. RESULTS: Reader 1 found edema in 16 of 20 runners and four of 12 nonrunners (P < .04); runners had a mean score of 4.7 and nonrunners had a mean score of 0.9 (P < .006). The average number of bones with edema was 3.4 for runners and 0.7 for nonrunners (P < .005). Reader 2 found edema in 16 of 20 runners and two of 12 nonrunners (P < .002); runners had a mean score of 4.5 and nonrunners had a mean score of 0.3 (P < .001). The average number of bones with edema was 3.6 for runners and 0.3 for nonrunners (P < .001). CONCLUSION: When the fast short inversion time inversion-recovery sequence is performed, edema seen within the marrow of runners on MR images may be due to exercise alone.