Abstract
Introduction: Magnetic resonance imaging (MRI) has become the cornerstone for pretreatment evaluation
of carcinoma tongue and provides accurate information regarding the extent of the
lesion and depth of invasion that helps the clinician to optimize treatment strategy.
Aim of the study is to correlate MRI and histopathological findings, to evaluate the
role of MRI in loco-regional tumor node metastasis (TNM) staging, and to assess the
depth of invasion of tongue carcinoma. Materials and Methods: This study was undertaken on 30 patients with clinical diagnosis of tongue carcinoma
referred for MR imaging at a tertiary care hospital over the 2-year period between
July 2017 and June 2019. MRI was performed with GE 1.5 Tesla scanner, neurovascular
(NV) array coil. Clinical and MRI staging of tongue carcinoma was done preoperatively
and correlated. Post-surgery, histopathological TNM staging was done and correlated
with clinical and MRI TNM staging. The cutoff value of histopathological (HP) depth
that could determine the existence of nodal metastasis was 5 mm. Results: In 30 patients diagnosed with tongue carcinoma, the incidence was higher in males
(92%). Moderate agreement (k = 0.512) was noted for T staging between clinical and
MRI staging assessments. Fair agreement (k = 0.218) was noted for N stage between
clinical and MRI staging assessments. There was good agreement (k = 0.871) for M stage
between the clinical and MRI staging assessments. Good agreement (k = 0.822 and k
= 0.767, respectively) was noted for both T staging and Nstaging between MRI and histopathology
staging assessments. The agreement for the T stage was poor (k = 0.012) between the
clinical and histopathology staging assessments. Agreement for the N stage was also
poor (k = 0.091) between the clinical and histopathology staging assessments. Mean
depth of invasion by histology and MRI was 14.22 mm and 16.12 mm, respectively. Moderate
agreement (k = 0.541) was noted between clinical and pathological tumor depth and
good agreement (k = 0.844) was noted between radiological and pathological tumor depth.
As for the T1WGd MRI depth with a cutoff value of 5 mm, the nodal metastasis rate
in the group with values >5 mm was 52%, and for those <5 mm was 24%, both of which
were significantly different (P = 0.040). Pearson’s correlation coefficient of HP
depth and T1WGd MRI depth was 0.851 (P < 0.001) suggesting that HP depth shows a strong
correlation with T1WGd MRI depth. Conclusion: MRI is the imaging modality of choice for evaluation of tongue carcinoma as MRI
helps in accurate staging of the tumor using TNM classification which is crucial for
optimizing treatment options. The current study shows a high correlation between MRI
and histopathological findings regarding thickness of tumor and depth of invasion.
MRI and histopathology assessments of tumor spread were equivalent to within 0.5 mm
DOI. Estimation of invasion depth using MRI as a preoperative study in oral tongue
carcinoma is essential in planning surgical treatment strategies such as the extent
of elective neck dissection. Invasion depth, which greatly affects occult node metastases,
must be included in the TNM staging of oral tongue carcinoma.
Keywords
Depth of invasion - magnetic resonance imaging - tumor node metastasis staging - tongue
carcinoma
