Evaluation of T2 value for detection of metastatic cervical lymph node in head and neck squamous cell carcinoma compared with 18F-FDG PET/CT

Abstract

Background: Difference in the staging of head and neck cancer leads to different treatments and managements
of the patients to minimize mortality and improve long-term health and social consequences.

Objective: This study aimed to utilize the T2 signal value on T2WI for early detection of metastatic lymph nodes.

Methods: We retrospectively reviewed 18-fluoro-deoxyglucose positron emission tomography/computed
tomography (18F-FDG PET/CT) and magnetic resonance imaging (MRI) results of patients with head and neck
squamous cell carcinomas, from January 2012 to February 2018. The ratio between the T2 signal values of the
lymph nodes and sternocleidomastoid muscles were calculated for each lymph node. Analytical comparisons
between T2 signal value ratios of the lymph nodes with and without 18F-FDG PET uptake were performed.
The differences of T2 signal value ratios in pre-treatment and post-radiation lymph nodes were analyzed.

Results: Twenty-six patients were recruited, with 54 lymph nodes in the suspected malignant group and 50
lymph nodes from the suspected benign group. There was no significant T2 signal value ratios in the suspected
metastatic as compared with benign nodes. However, the minimum T2 signal value ratio of the suspected benign
group was not lower than 1.5. The receiver operating characteristic (ROC) analysis of the mean T2 signal
value ratio at cut-off value of 1.33 showed an area under the curve (AUC) of 0.55, a sensitivity of 57.14% and
a specificity of 56.25%. History of previous radiation on the neck region showed significantly decreased T2 signal
value ratios when both groups of lymph nodes were combined and in the suspected benign group. Inter-observer
reliability was excellent (ICC 0.870).

Conclusions: No cut-off T2 signal value ratio exhibits high sensitivity or specificity for detection of metastatic
lymph nodes.