Squamous cell carcinoma of the oral tongue: MR T staging with histopathological correlation

Objective: The aim of this study was to evaluate the diagnostic accuracy of MR in evaluation of T staging of carcinoma of the oral tongue with histopathological correlation. Materials and methods: 62 patients with squamous cell carcinoma of the oral tongue proved on biopsy and underwent surgery at our institute during the period between 1997 to 2001 forms the material of this study. MRI study was done in each case with T1W spin echo (SE) and fat suppressed T2W spin echo/STIR (short tau inversion recovery) sequences using 1.0T MR scanner (Mangnetom Expert Siemens, Germany). The results were compared with the pathological T stage (TNM classification) of lesions including involvement of adjoining structures. Results: A positive correlation of T stages (TNM classification) obtained in 54 of 62 cases with an accuracy of 87.09%. The accuracy of MR is excellent (97.6%) for predicting the relationship of tumor to the midline and involvement of surrounding structures. MR however overestimated lesion size in three cases (P T1 & T2 seen as MR T2 & T3 respectively) and overstaged three lesion showing involvement of extrinsic muscles of tongue and muscles of floor of mouth because of perilesional edema which are not proved at surgery. Also MR missed one out of two cases with mandibular involvement. Conclusion: MR showed high accuracy in accessing T stage of the disease in carcinoma of oral tongue. It is particularly useful for detecting lesions including small submucosal lesions and involvement of deeper tissues and surrounding structures that are difficult to evaluate clinically and thus helps in appropriate treatment planning.