MRI and CT of tumors of the pharynx: comparison of the two imaging procedures including fast and ultrafast MR sequences

Abstract

The aim of this prospective study was to compare the diagnostic value of computed tomography (CT) and magnetic resonance imaging (MRI) in the evaluation of tumors of the nasopharynx, oropharynx and hypopharynx. For this reason, we performed CT and MRI in a total of 473 patients with neoplasms of the nasopharynx [116], oropharynx [282] and hypopharynx [39]. Furthermore, the MR imaging protocol had to be optimized including 2D and 3D gradient echo sequences. We compared the use of conventional and fast spin echo and 3D gradient echo sequences for the evaluation of tumors of the nasopharynx and the skull base, and we evaluated 2D fast and ultrafast MR sequences for the detection and delineation of tumors of the oropharynx and hypopharynx. MRI yielded better results than CT in the detection of pharyngeal neoplasms. The differentiation of tumor and inflammatory tissue was best achieved using MRI. Contrast-enhanced 3D GE sequences improved the diagnostic value of MRI of the nasopharynx. Fast and ultrafast 2D MR sequences increased the contrast between orofacial tumors and surrounding tissues. Functional MR images (phonation studies, Valsalva's maneuver) were attainable using ultrafast sequences thus enhancing the diagnostic value of MRI in the case of tumors of the hypopharynx. T2-weighted turbo (fast) spin echo sequences with relatively short acquisition times proved to be superior to conventional T2-weighted spin echo sequences. In conclusion, MRI is the imaging modality of choice in the evaluation of pharyngeal neoplasms. Conventional T2-weighted SE should be substituted by fast T2-weighted SE sequences. 3D GE sequences should be integrated in the MR imaging protocol of the nasopharynx. Fast and ultrafast 2D GE sequences should be applied in the evaluation of tumors of the oropharynx and hypopharynx.