Spin lock and magnetization transfer imaging of head and neck tumors.

Abstract

To evaluate and compare the spin lock and magnetization transfer techniques in the differentiation of benign and malignant head and neck tumors at magnetic resonance (MR) imaging. Forty consecutive patients with histologically verified head and neck tumors (20 malignant and 20 benign tumors, including five infections) were studied with a 0.1-T MR unit. The spin lock and magnetization transfer effects were defined as 1-(signal intensity with stronger preparation pulse/signal intensity with weaker preparation pulse). A strong correlation between the spin lock and magnetization transfer effects was found (r = 85, P < .001). With a spin lock effect of 0.48 and a magnetization transfer effect of 0.32 as the thresholds, sensitivity for detecting a malignant tumor was 95% and 94%, respectively, and specificity was 60% and 65%. Low spin lock and magnetization transfer effects are characteristic of benign tumors. High spin lock and magnetization transfer effects were associated with malignancy, but there were overlapping values for salivary gland infections, some benign tumors, and malignancies. The spin lock technique seems to be an effective method for generating magnetization transfer-based contrast in the head and neck tumors.