Comparison of diagnostic role of diffusion weighted imaging in the differentiation of benign and malignant cervical group of lymph nodes with pathological correlation- a one year obsevational study at kles dr prabhakar kore hospital and mrc, belagavi

Abstract

“Lymphadenopathy” is defined as an abnormality in size and / or alteration in consistency of the lymph nodes. There are around 800 lymph nodes in the entire human body out of which 300 are present in the head and neck region. Common causes of the cervical lymphadenopathy are infection, metastasis from the neck primaries, granulomatous diseases and miscallaneuos conditions like Castleman’s disease, Kikuchi’s disease, Kimura’s disease, Immunoblastic lymphadenopathy and post radiation changes. Most common infection resulting in cervical lymphadenopahy is tuberculosis in India. Most common metastases to the cervical nodes are seen in cases of carcinomas of oral cavity, tongue, larynx and pharynx. Ovareall 57.8% of head and neck cancers occur in Asian continent, with a major bulk of cases seen in India. Out of these, 90% of the head and neck carcinomas are seen to arise from the mucosa of oral cavity and are of squamous cell origin. Ultrasound, computed tomography and magnetic resonance imaging are the preliminary radiological modalities commonly used to diagnose the cases and plan the further management of the patients presenting with cervical lymphadenopathy. Nuclear studies like the Positron emission tomography (PET) and single photon emission CT (SPECT) are also included invariably but lack spatial resolution and may show false positive results due to high FDG take –up in the inflammatory nodes. MRI helps in characterizing the lymph nodes depending on the alteration in signal intensities on T1, T2 and DWI sequences and the Apparent Diffusion Coefficient (ADC) values involving the pathological lymph node. DW- MRI is an emerging, non-invasive modality in the detection of the nodes. It is mainly based on the principle of “Brownian motion” of the water molecules across the cell membranes and shows diffusion restriction in the tissues with high cellularity. It helps in detection of metastasis in subcentimetric nodes in a substantial percentage of neck malignancies which are clinically inevident. The aim of the study was to differentiate the cervical lymphadenopathy into benign and malignant etiology depending on the DW-MR imaging features and ADC values. The objective was to compare the findings of DWI/ ADC of cervical nodes to that of FNAC/ histopathology reports.