Inversion-recovery fast spin-echo MR imaging: efficacy in the evaluation of head and neck lesions.

To compare the efficacies of fast spin-echo (FSE) and inversion-recovery FSE (IRFSE) magnetic resonance (MR) imaging in evaluating head and neck disorders, the authors evaluated 46 lesions in 23 consecutive patients. Twenty-seven lesions were related to neoplasms; 19 lesions resulted from infectious, allergic, or radiation-induced inflammation. Conventional T1-weighted, FSE, and IRFSE images were obtained in all patients. The FSE and IRFSE images were qualitatively compared in an unblinded manner for conspicuity of lesion margins and extent. IRFSE imaging improved conspicuity of 22 lesions (48%) and showed equal conspicuity of 18 (39%). IRFSE imaging proved most useful for small lesions with long T2 relaxation times that were surrounded by fat. IRFSE imaging improved visibility of small optic nerve gliomas, salivary gland inflammation, peripheral nerve tumors, and small lymph nodes. Early changes secondary to spread of tumor across fascial planes were also well visualized with IRFSE sequences. In six lesions (13%) that did not have long T2 relaxation times, the FSE images provided better conspicuity. The authors conclude that by improving conspicuity of small lesions adjacent to or surrounded by fat, IRFSE sequences can supplement FSE sequences in imaging the head and neck.