Role of Diffusion Weighted MRI in the Differentiation between Benign and Metastatic Abdomino Pelvic Lymph Nodes
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- Category: Vol. 84, September 2016
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Role of Diffusion Weighted MRI in the Differentiation between Benign and Metastatic Abdomino Pelvic Lymph Nodes, MOHAMED ESSAM, HANEY A. SAMI, MARWA S.A. EL-NAFARAWY and AHMED EL-ASHWAH
Abstract
Background: Evaluation of lymph node metastasis is essential for oncologic staging as it affects the treatment plan and the patient's prognosis. Histopathological analysis is the most accurate method for the differentiation between benign and malignant lymph nodes. However tissue sampling in the abdomen and pelvis is challenging and can lead to false-negative results due to inadequate sampling. Recently PET-CT is used for imaging of lymph node metastasis through the use of the standard maximum uptake value (SUV max), however, it carries risks of exposure to radioactive material and is expensive. On the other hand, diffusion weighted MRI (DWI) does not require the use of radioactive material or even contrast media. Moreover, it can be performed in a relatively short amount of time and is inexpensive.
Aim of the Work: The purpose of this study is to study the value of diffusion weighted MRI in the differentiation between benign from metastatic lymph nodes in comparison to PET-CT.
Patients and Methods: Thirty cases; 21 males and 9 females with known malignancy were included in this study with an age range from 23 to 82 (average age is 57). The study was performed in the period from May 2013, till January 2015. Full clinical history of all patients was taken and their laboratory investigations, histopathological data and previous imaging were reviewed. Conventional and diffusion weighted MRI and PET-CT studies were performed for lymph nodes evaluation.
Results: The ADC values were significantly lower in metastatic lymph nodes (mean ADC value is 0.91±0.17 X 10–3mm2/sec) than in benign lymph nodes (mean ADC value is 1.31±0.20mm2/sec). The difference between the mean ADC values of benign and malignant lymph nodes was statistically significant (p<0.0001). There was a statistically significant inverse correlation between the ADC values and the SUV max values suggesting that DWI can also provide additional data on the pathophysiology of tumors similar to that provided by the SUV in PET CT.