Comparison Between Computed Tomography and Ultrasound for Presurgical Evaluation of Oral Tongue Squamous Cell Carcinoma Tumor Thickness.

Purpose: To compare the accuracy of oral tongue squamous cell carcinoma (OTSCC) tumor thickness (TT) measured on CT to intraoperative ultrasound (US) and histopathology. Methods and materials: Twenty-six patients with OTSCC who underwent tumor resection by a single surgeon with simultaneous intraoperative US between 3/2016 and 4/2019 were prospectively identified, and their data reviewed. TT was independently measured in 19 patients who underwent preoperative CT (cTT) by two neuroradiologists blinded to US and histological results. The confidence level of interpretation of cTT was recorded by each reader using a 5-point Likert scale. The degree of dental artifact on CT was also scored. cTT was compared to TT measured on intraoperative US (uTT) and histopathologic assessment of TT (hTT). Results: OTSCC was visualized on CT in 52% (10/19) and 63% (12/19) of cases for readers 1 and 2, respectively. Mean Likert score was 0.42 for reader 1 and 0.73 for reader 2. Mean cTT of OTSCCs was 5.8 mm +/- 1.7 mm (n = 11). In comparison, mean uTT and hTT were 7.6 mm+3 5 mm and 7.1 +/- 4.2 mm, respectively. The Pearson coefficient (95% confidence interval) was 0.10 (-0.53-0.66) between cTT and hTT (n = 11) and 0.93 (0.74-0.98) between uTT and hTT. Conclusions: Preoperative CT is not reliable for assessment of TT in OTSCC compared to US and histopathology, particularly for OTSCC under 10 mm. US offers a practical complementary imaging tool with a unique role for primary tumor assessment that can aid in pre-operative planning, especially for small tumors.