[Comparison of CT and MRI methods in diagnosis of tumors of the para- and retropharyngeal space and temporal bone].

Abstract

The aim of this paper was to compare the diagnostic value of computed tomography (CT) and magnetic resonance imaging (MRI) in the evaluation of malignant tumors of the temporal bone, of paragangliomas of the glomus tympanicum and jugulare as well as of malignant tumors of the para- and retropharyngeal space. 67 patients with tumors of the temporal bone--28 cases with malignant tumors and 39 cases with paragangliomas--were examined with MRI and CT. MRI had true-positive findings in nearly 93, CT in 89% of the patients with malignant tumors of the temporal bone. MRI is therefore recommended as the primary imaging investigation of malignant tumors of the temporal bone. Whereas the temporal bone is best visualized by high-resolution CT with thin slices, the tumor extension--especially cranial spread into the middle and posterior cranial fossa and caudal spread into the infratemporal fossa--is better detected on MRI. Enhanced T1-weighted spin-echo images with fat-signal suppression are most suitable for this purpose. Using 3D sequences, partial volume effects can be avoided with an attainable slice thickness of 0.8-1.0 mm. Furthermore, arbitrary slices--very helpful when studying the complex anatomy of the skull base--can be calculated from a 3D data set. MRI had true-positive findings in 97, CT in nearly 90% of the patients with paragangliomas. Furthermore, the response of paragangliomas to radiotherapy can be more accurately assessed on MR--independent of and before volumetric changes.(ABSTRACT TRUNCATED AT 250 WORDS)