Dynamic magnetic resonance imaging of cervical lymph nodes in patients with oral cancer: utility of the small region of interest method in evaluating the architecture of cervical lymph nodes

Objective  Our purpose was to evaluate the utility of the small region of interest (ROI) method to detect the architecture of cervical lymph nodes and the specificity of time-intensity curves for tissue present in cervical lymph nodes. Methods  Specimens were taken from 17 lymph nodes of eight patients (ten sides of the neck) with oral squamous cell carcinoma who underwent dynamic contrast-enhanced magnetic resonance imaging (MRI) and neck dissection between 2005 and 2007 at our hospital. Two methods of constructing time-intensity curves were compared: the conventional method that uses relatively large ROIs, and a new method that uses small ROIs. Curves made with the small ROI method were then compared to histopathological findings for dissected lymph nodes. Results  The small ROI method allowed differences in signal intensity to be discerned at the tissue level, which was not possible with the conventional large ROI method. Curves for normal lymphoid tissue tended to be type I, those for tumor cells tended to be type II, and those for keratinization/necrosis tended to be types III and IV, indicating that time-intensity curves can be specific to tissue type within lymph nodes. Conclusion  The small ROI method was useful for evaluation of the architecture of cervical lymph nodes.