IMPACT OF MAGNETIC-RESONANCE-IMAGING AND COMPUTED-TOMOGRAPHY IN ADVANCED INTRAORAL CANCER - A COMPARATIVE CLINICAL, RADIOLOGICAL AND MORPHOLOGICAL-STUDY

The objective of this prospective study is to assess the impact of mag netic resonance imaging (MRI) and computed tomography (CT) as compared to physical examination in the choice of type of surgery for advanced intraoral cancers (with or without resection of the mandibula). From 1990 to 1993, we operated on 21 intraoral malignant tumors with segmen tal resection of the mandibula followed by a histological examination. The preoperative evaluation consisted of an MRI (n = 8), a CT (n = 8) or both (n = 5). MRI suspected an infiltration of the bone in 9 cases , CT in 4 and physical examination in 16. This was histologically conf irmed in 6 of the 21 patients only. MRI and CT both have a high sensit ivity, as does physical examination, but neither have a good specifici ty (physical examination: 5 true positive, 4 true negative, 11 false p ositive, 1 false negative; MRI: 4 true positive, 4 true negative, 5 fa lse positive, 0 false negative; CT : 3 true positive, 7 true negative, 3 false positive, 0 false negative). In conclusion, the decision of a mandibular resection can only be taken after a careful physical exami nation, including palpation under general anesthesia in a fully relaxe d patient. This is best accomplished during the pretherapy bronchoesop hagoscopy, routinely performed for the detection of synchromous second primary tumors using tumors using toluidin blue as a vital staining m ethod. If this initial evaluation gives a suspicion of a massive infil tration of the mandible, an MRI, rather than a CT, sould be performed to determine the extent of the ressection because of a high rate of ar tefacts with CT.