Comparison of dynamic contrast-enhanced gradient-echo and spin-echo sequences in MR of head and neck neoplasms.

PURPOSE To investigate the utility of dynamic contrast-enhanced gradient-echo MR imaging of head and neck lesions and to compare this technique with the commonly used spin-echo contrast-enhanced fat-saturation technique. METHODS Twenty-two patients with a total of 23 head and neck neoplasms underwent dynamic gradient-echo and spin-echo MR imaging studies. The spin-echo and dynamic gradient-echo images were compared in each case by consensus of three observers for differences in tumor conspicuity and delineation of margins, particularly with regard to invasion of adjacent structures. When possible, pathologic and/or surgical confirmation of tumor extent was obtained. Relative contrast was also calculated to determine objectively the degree of tumor enhancement with respect to background mucosa. RESULTS The dynamic gradient-echo images showed better or equal delineation of the tumor margins by subjective observation in all but two cases. Temporally different enhancement patterns were noted for lesions, background mucosa, and adjacent reaction and edema. The dynamic gradient-echo technique provided better relative contrast than the spin-echo technique in 17 (77%) of 22 lesions. CONCLUSION Dynamic gradient-echo MR imaging is superior to conventional contrast-enhanced spin-echo imaging in delineating the margins and extent of tumor. This technique provided observers with added confidence in their interpretations and suffered from fewer technical limitations.