Fig. 1

T1W1 MRI showed measurement of MRI-assessed tumor thickness in three dimensions. All reference lines (red line) were defined as the longest tumor diameter in each direction. a. Axial tumor thickness (aTT) (orange line), b. Coronal tumor thickness (cTT) (yellow line). c. Sagittal tumor thickness (sTT) (purple line). In the coronal view, a thin high signal intensity (green arrow line) was used to identify the deep lingual artery and inferior lateral area of high signal intensity (asterisk) was indicated the sublingual space. Paralingual distance was defined as the distance between the lateral aspect next to the deep lingual artery and medial border of the tumor (dotted line). Sublingual distance was determined by measuring the vertical distance between the inferior border of tumor and the sublingual space (black arrow line)