Magnetic resonance imaging: dynamic contrast enhancement and diffusion-weighted imaging to identify malignant cervical lymph nodes

Murilo Bicudo Cintra,Antonio Carlos Dos Santos,Hilton Ricz,Mahmood F Mafee

doi:10.1590/0100-3984.2017.0005

Murilo Bicudo Cintra, Antonio Carlos Dos Santos + Show 2 more

Open Access

https://doi.org/10.1590/0100-3984.2017.0005

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Abstract

ObjectiveTo examine the potential of two magnetic resonance imaging (MRI) techniques-dynamic contrast enhancement (DCE) and diffusion-weighted imaging (DWI)-for the detection of malignant cervical lymph nodes.Materials and MethodsUsing DCE and DWI, we evaluated 33 cervical lymph nodes. For the DCE technique, the maximum relative enhancement, relative enhancement, time to peak enhancement, wash-in rate, wash-out rate, brevity of enhancement, and area under the curve were calculated from a semi-quantitative analysis. For the DWI technique, apparent diffusion coefficients (ADCs) were acquired in the region of interest of each lymph node. Cystic or necrotic parts were excluded. All patients underwent neck dissection or node biopsy. Imaging results were correlated with the histopathological findings. None of the patients underwent neoadjuvant treatment before neck dissection.ResultsRelative enhancement, maximum relative enhancement, and the wash-in rate were significantly higher in malignant lymph nodes than in benign lymph nodes (p < 0.009; p < 0.05; and p < 0.03, respectively). The time to peak enhancement was significantly shorter in the malignant lymph nodes (p < 0.02). In the multivariate analysis, the variables identified as being the most capable of distinguishing between benign and malignant lymph nodes were time to peak enhancement (sensitivity, 73.7%; specificity, 69.2%) and relative enhancement (sensitivity, 89.2%; specificity, 69.2%).ConclusionAlthough DCE was able to differentiate between benign and malignant lymph nodes, there is still no consensus regarding the use of a semi-quantitative analysis, which is difficult to apply in a clinical setting. Low ADCs can predict metastatic disease, although inflammatory processes might lead to false-positive results.

Highlights

Malignant cervical lymph nodes constitute a negative prognostic indicator in the treatment of head and neck cancer[1,2,3,4]
No statistically significant differences were found among the apparent diffusion coefficients (ADCs), wash-out rate (WoR), brevity of enhancement (BrevE), and area under the curve (AUC) values in terms of their capacity to differ
No statistically significant differences were found among the ADC, WoR, BrevE, and AUC values in terms of their capacity to differentiate between malignant and benign lymph nodes

Summary

Introduction

Malignant cervical lymph nodes constitute a negative prognostic indicator in the treatment of head and neck cancer[1,2,3,4]. The development of noninvasive imaging biomarkers for use in treatment planning has the potential to improve treatment strategies Anatomical imaging techniques such as ultrasound, contrast-enhanced computed tomography, and contrastenhanced magnetic resonance imaging (MRI) are capable of detecting enlarged lymph nodes[5,6,7,8], in the cervical chains. Such techniques are less sensitive for identifying malignancy in some cases[9]. Ultrasound-guided fine needle aspiration biopsy of lymph nodes is capable of detecting malignancy, it is an invasive method that is operator-dependent and has a high rate of false-negative results[10]

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