Diagnostic value of magnetic resonance lymphography in preoperative staging of clinically negative necks in squamous cell carcinoma of the oral cavity: a pilot study.

Pilot study evaluating the diagnostic value of magnetic resonance lymphography (MRL) compared with conventional imaging techniques in the preoperative staging of the clinically (palpable) negative neck (cN0) in squamous cell carcinoma of the oral cavity (SCCOC). Patients with SCCOC without clinical evidence of lymph node metastasis and scheduled for surgery underwent MRL in combination with ultrasound with or without fine needle aspiration cytology and multi-detector computer tomography. MRL images were interpreted by 2 independent radiologists. All patients were planned for resection of the primary tumor and a selective neck dissection of levels I-III. Histopathologic results were evaluated as the gold standard and compared with preoperative findings. One of nine evaluated patients had a metastatic node on histopathologic analysis. In all but 1 patient, MRL showed possible metastatic spread in at least 1 node. On a node-to-node basis, negative predictive value (NPV) and sensitivity reached 100% for 1.5- en 3Tesla (T) MRL, specificity reached 92% at 1.5T and 93% at 3T MRL, and positive predictive value (PPV) was 8% at 1.5T MRL, for both radiologists. PPV at 3T MRL was 10% and 9%, for radiologists I and II, respectively. This pilot study shows that MRL has a high NPV based on a node-to-node analysis. However, its PPV was only 10%, and therefore its use as a single imaging technique in the preoperative staging of the cN0 neck in SCCOC seems to be limited. Further studies are needed to confirm these data.

Diagnostic accuracy and additional value of diffusion-weighted imaging for discrimination of malignant cervical lymph nodes in head and neck squamous cell carcinoma.

INTRODUCTION: The aim was to determine the diagnostic accuracy and additional value of diffusion-weighted imaging for detection of malignant lymph nodes in head and neck squamous cell carcinoma. METHODS: Two hundred nineteen lymph nodes, predominantly smaller than 10 mm (95.4%), in 16 consecutive patients were evaluated at 1.5 T. Lymph nodes were evaluated for maximum short axial diameter, morphological criteria, and apparent diffusion coefficient (ADC) values (b = 0 and b = 1,000 s/mm(2)). Sensitivity, specificity, positive and negative predictive values as well as diagnostic odds ratios (DORs) and areas under the curves (AUCs) of ROC curves were calculated for the various magnetic resonance imaging (MRI) criteria individually and in combination. Histological examination of lymph nodes in the neck dissection specimen was the gold standard to determine malignant involvement. RESULTS: The optimal ADC threshold was 1.0 x 10(-3) mm(2)/s. Using this cutoff point, sensitivity and specificity were 92.3% and 83.9%, respectively. When used in combination with size and morphological criteria, ADC value <1.0 x 10(-3) mm(2)/s was the strongest predictor of presence of metastasis (DOR = 97.6). A model which added ADC values to the other MRI criteria performed significantly better than a model without ADC values: AUC = 0.98 versus AUC = 0.91 (p = 0.036). CONCLUSION: In this study, with predominantly small lymph nodes, the ADC criterion is the strongest independent predictor of presence of metastasis. The use of ADC values in combination with the other MRI criteria significantly improves the discrimination between malignant and benign lymph nodes.