Diagnostic value of CT and MRI in the detection of paratracheal lymph node metastasis

The presence of paratracheal lymph node (PTLN) metastasis harbours a worse prognosis. Uniform guidelines on PTLN dissection are missing, mainly because of the value of diagnostic techniques for the detection of PTLN metastasis are not clear. This study is performed to identify CT and MRI criteria for detection of PTLN metastasis. 149 patients who underwent laryngectomy and a PTLN dissection between 1990 and 2010 were included. Patient, tumour, treatment and follow up data were collected. On computed tomography (CT) and magnetic resonance imaging (MRI) different test criteria were examined. Considering PTLN with a maximal axial diameter of ≥5 mm as positive predicts PTLN metastasis best: sensitivity and specificity 70% and 36% (CT) and 50% and 71% (MRI). Other risk factors for PTLN metastasis were subglottic extension of the tumour (sensitivity is 45%) and clinical positive neck status (sensitivity is 59%). When atleast one of these risk factors was present and the status of PTLN was considered positive, a high sensitivity (90% for CT and 100% for MRI) and a lower specificity (19% for CT and 32% for MRI) was found. If atleast one of the risk factors such as subglottic extension, clinical positive neck and PTLN with a maximal axial diameter of ≥5 mm is present, sensitivity and negative predictive value for the prediction of PTLN metastasis are high, but the specificity is low. These risk factors can be used to select laryngectomy patients for PTLN dissection.