Fast spin-echo imaging of the neck: comparison with conventional spin-echo, utility of fat suppression, and evaluation of tissue contrast characteristics.

PURPOSE To determine whether fast spin-echo sequences could replace conventional spin-echo methods in the evaluation of head and neck neoplasms and associated adenopathy and to evaluate differences in tissue contrast characteristics between conventional spin-echo and fast spin-echo examinations of head and neck disease. METHODS Twenty-seven patients with squamous cell carcinoma were imaged on a 1.5-T imager with both conventional spin-echo and fast spin-echo sequences with identical section thickness and position. Twenty-one of the 27 fast spin-echo studies were performed with frequency-selective fat suppression. Three radiologists independently evaluated the images using a five-point scale to compare primary lesion margin definition and conspicuity, lymph node margin definition and conspicuity, gross motion artifact, and flow artifact. Quantitative percent contrast and contrast-to-noise ratios were calculated and compared in 7 cases with fat-suppressed fast spin-echo. RESULTS Fast spin-echo was preferred by all three readers for lesion margin conspicuity and lymph node conspicuity. Gross motion and flow artifact demonstrated trends toward reader preference for fast spin-echo. Quantitative contrast values for fast spin-echo were significantly greater than those for conventional spin-echo. CONCLUSIONS Fast spin-echo with fat suppression can replace conventional spin-echo at a time savings of more than 50% and improves tissue contrast and the conspicuity and definition of margins for primary lesions and lymph nodes. Fat-suppression heterogeneity remains the major limitation of this technique. Thus, careful attention to fat-suppression failure and unwanted water saturation is essential.