The Usefulness of Intraoral Ultrasonography and Post-Contrast Three-Dimensional Fast Field Echo Imaging in the Evaluation of Radiological Depth of Invasion of Oral Tongue Squamous Cell Carcinoma: Comparison with Pathological Depth of Invasion Assessment

Aim Squamous cell carcinoma (SCC) is the most common malignancy in the oral tongue. Depth of invasion (DOI) of the tongue SCC is known as a predictor of recurrence and survival in patients. Both intraoral ultrasonography (ioUS) and post-contrast three-dimensional fast field echo (3D-FFE) imaging are useful for predicting pathological DOI and can contribute to effective treatment plans and a positive prognosis. The purpose of this study was to evaluate the usefulness of ioUS in comparison with post-contrast 3D-FFE imaging for assessing radiological DOI and compare radiological DOI and pathological DOI in patients with oral tongue SCC. Methods Fifteen patients were included in this study conducted between August 2018 and March 2020. Spearman's rank correlation coefficient was used to compare radiological DOI with pathological DOI. Results Both ioUS-derived DOI (9.98 mm) and 3D-FFE-derived DOI (9.86 mm) were larger than pathological DOI (5.7 mm). The Pearson’s correlation coefficient (PCC) between ioUS-derived DOI and pathological DOI was 0.63 and between 3D-FFE-derived DOI and pathological DOI was 0.58.