title: Accuracy of MRI in Prediction of Tumour Thickness and Nodal Stage in Oral Tongue and Gingivobuccal Cancer With Clinical Correlation and Staging.
abstract: BACKGROUND
  Squamous cell carcinoma of lower gingivo-buccal complex and tongue are the most common cancer in the Indian sub-continent. The value of imaging in the staging of Oral Squamous Cell Carcinoma (OSCC) is in judging operability, assessment of the prognostic characteristics and dimensions of the primary tumour, depth of tumour invasion, the presence of cervical metastasis and detection of bone infiltration.
  
  
  OBJECTIVE
  This study evaluated squamous cell carcinomas of the oral cavity (tongue and gingivo-buccal complex) on the basis of their appearance, soft tissue extent, depth of tumour invasion and staging. Further, this study assessed the accuracy of MRI in the detection of cervical lymph nodal metastasis on the basis of ADC values on diffusion weighted MR sequence.
  
  
  METHODS
  T1- and T2-weighted MR, diffusion-weighted sequences and post contrast T1W sequences were performed in various planes on biopsy proven squamous cell carcinomas (61 cases) involving tongue and/or gingivo-buccal region. Depth of tumour invasion was calculated on axial images of post contrast T1W images. The Apparent Diffusion Coefficient (ADC) was measured by using two b factors (500 and 1000 s/mm(2)). MRI findings were compared clinically and histopathologically.
  
  
  RESULTS
  Average depth of invasion calculated on MRI was 8.47mm and by histopathology was 6.85mm. Pearson's correlation coefficient was 0.988. Shrinkage factor was 0.8. A 71% of patients with depth of invasion greater than 9mm showed evidence of cervical lymph nodal metastasis at one or another levels. Cut-off value to discriminate between malignant and benign lymph nodes was 1.038 x10-3 mm(2)/s in the present study.
  
  
  CONCLUSIONS
  Depth of tumour invasion in oral malignancies can be measured reliably on MRI which helps in predicting cervical lymph node metastasis. Benign or malignant cervical lymph nodes can be differentiated on diffusion-weighted imaging of MRI on the basis of their ADC values.
authors: Post Graduate Student, Datta Meghe Institute of Medical Science , Maharashtra, India .
authors: Varun
authors: V
authors: Goel
authors: Associate Professor, Department of Radio-Diagnosis, Datta Meghe Institute of Medical Science , Maharashtra, India .
authors: Pratap Singh
authors: PS
authors: Parihar
authors: Intern, Datta Meghe Institute of Medical Science , Maharashtra, India .
authors: Akhilesh
authors: A
authors: Parihar
authors: Radiologist, Datta Meghe Institute of Medical Science , Maharashtra, India .
authors: Ashok Kumar
authors: AK
authors: Goel
authors: Lecturer, Department of Oral and Maxillofacial Surgery, Datta Meghe Institute of Medical Science, Sharad Pawar Dental College , Wardha, Maharashtra, India .
authors: Kapil
authors: K
authors: Waghwani
authors: Consultant, Department of Oral and Maxillofacial Surgery, Jabalpur Hospital , Madhya Pradesh, India .
authors: Richa
authors: R
authors: Gupta
authors: Lecturer, Department of Oral and Maxillofacial Surgery, Datta Meghe Institute of Medical Science, Sharad Pawar Dental College , Wardha, Maharashtra, India .
authors: Umesh
authors: U
authors: Bhutekar
keywords: Apparent diffusion coefficient; Diffusion weighted imaging; Oral squamous cell carcinoma