Objective: Our aim was to describe the MRI appearance of myocutaneous flaps and to determine whether postoperative radiation therapy affects imaging.
Materials and methods: We retrospectively reviewed 30 myocutaneous flaps in 27 patients (n = 165 examinations; mean, 6.1 examinations per patient). Examinations were analyzed for flap type, location, degree of atrophy, signal intensity, and enhancement.
Results: Sixty-three percent (19/30) of the flaps developed high T1-weighted signal (mean, 15 months); 83% (25/30) developed high T2-weighted signal (mean, 10 months). This occurred sooner in those patients with postoperative radiation therapy (9 vs 12 months). T2-weighted signal returned to baseline in 32% (8/25) of the flaps (mean, 21 months); this occurred sooner in flaps not exposed to postoperative radiation (10 months vs 38 months). Seventy-one percent (20/28) of the flaps enhanced greater than the background musculature. Enhancement was seen more frequently in patients treated with postoperative radiation therapy than those not treated with radiation (83% vs 63%). All flaps atrophied; however, the two functional latissimus dorsi flaps atrophied less. Although increased T2-weighted signal and enhancement were seen in flaps after postoperative radiation therapy as compared with those without, this was not significant (p = 0.35 and p = 0.40, respectively).
Conclusion: Myocutaneous flaps used in orthopedic reconstructive surgery typically show increased signal intensity on T2-weighted images and contrast enhancement initially, followed by some degree of atrophy and increased signal intensity on T1-weighted images. Postoperative radiation therapy may increase the likelihood that the flap will exhibit increased T2-weighted signal and enhancement.