A COMPARISON OF MR SEQUENCES FOR LESIONS OF THE PAROTID-GLAND

PURPOSE: To compare six MR sequences (plain and gadolinium-enhanced fa t suppressed T1-weighted spin echo, T2-weighted standard spin echo, fa t-suppressed and non-fat-suppressed T2-weighted fast spin echo, and in version-recovery T2-weighted fast spin echo) in their ability to detec t, delineate, and characterize lesions of the parotid gland. METHODS: Fifty-eight parotid gland lesions imaged on 47 examinations were retro spectively evaluated by three blinded observers. Several outcome-relat ed variables were compared by the above six sequences: imaging time, i mage quality, anatomic sharpness of parotid space, subjective lesion c onspicuity, detected abnormality volume, number of individual lesions or discrete lobulations, conspicuity of invasion into adjacent boundar ies and structures, and overall diagnostic value. RESULTS: Differences in the above outcome variables between sequences did not correlate wi th MR scanner software upgrade level, coil type, or lesion-dependent c haracteristics. Fat-suppressed fast spin-echo T2-weighted and inversio n-recovery fast spin-echo T2-weighted sequences resulted in significan tly higher scores for lesion conspicuity, detected abnormality volume, and overall diagnostic value. T1-weighted images resulted in the next highest scores, whereas gadolinium-enhanced T1-weighted and standard spin-echo T2-weighted sequences performed poorly for most parotid lesi ons. CONCLUSION: MR imaging of the parotid gland should include fat-su ppressed, long-repetition-time, fast spin-echo T2-weighted, and T1-wei ghted sequences. Gadolinium-enhanced images need not be obtained routi nely.