International Research Journal of Pharmacy and Medical Sciences ISSN (Online): 2581-3277 9 Ansam Moyaser Othman, Tara Farooq Kareem, Loban Fadhil Alwan Al-Hilli, and Mohammed Al-Hilli, “Diffusion Weighted MRI in Differentiating Benign from Malignant Cervical Lymph Nodes,” International Research Journal of Pharmacy and Medical Sciences (IRJPMS), Volume 7, Issue 6, pp. 9-13, 2024. Diffusion Weighted MRI in Differentiating Benign from Malignant Cervical Lymph Nodes Ansam Moyaser Othman 1 , Tara Farooq Kareem 2 , Loban Fadhil Alwan Al-Hilli 3 , Mohammed Al-Hilli 4 1 MBCHB CABMS, Radiology Department, Al Yarmouk Teaching Hospital, Baghdad, Iraq 2 MBCHB, CABMS, Consultant Radiologist, Lecturer at College of medicine University of Baghdad 3 MBCHB, CABMS, Radiology Department, Baghdad hospital, Medical city complex, Baghdad, Iraq 4 Consultant Radiologist, M.B.Ch.B - F.I.B.M.S Corresponding author: Tara Farooq Kareem, Email: tarafaroukkareem@gmail.com Abstract— Background: The evaluation of cervical lymph nodes is essential for the diagnosis and staging of malignancies, as well as for treatment planning and monitoring. While ultrasound imaging, contrast-enhanced computed tomography, and contrast-enhanced MRI facilitate the identification of enlarged cervical lymphadenopathies, none of these modalities achieves optimal accuracy. Objectives: To evaluate the diagnostic efficacy of DWI in the assessment of cervical lymph nodes in a cohort of Iraqi patients, some of whom had head and neck cancer. Methods: A prospective study conducted at the Oncology Teaching Hospital, Medical City, involved a total of 39 patients with enlarged cervical lymph nodes. They were examined utilizing 1.5 T MRI. DWI was conducted with b values of 0 and 1,000 s/mm². The short axis diameter and ADC values (minimum, maximum, and mean) were assessed for benign and malignant neck lymph nodes, and the results were compared with histological findings obtained through either fine needle aspiration or excisional biopsy. The optimal ADC thresholds were assessed using receiver operating characteristic (ROC) curves to distinguish between cancer and benign neck lymph nodes. Result: The histopathological analysis of included cervical lymph nodes indicated that 56.4% (n=22) were benign, whereas 55% (n=44) were malignant neck lymph nodes, respectively. The ADC values of malignant cervical lymph nodes were significantly lower than those of benign cervical lymph nodes (p < 0.001); 0.6771 ± 0.145 × 10^- 3 mm²/s compared to 1.067 ± 0.257 × 10^-3 mm²/s (mean ADC). The ideal mean ADC threshold was 0.965 x 10^-3 for differentiating cancer from benign cervical lymph nodes, exhibiting a sensitivity of 95.5% and a specificity of 88.2%. Conclusion: MR diffusion imaging and ADC values serve as a non-invasive modality that significantly aids in the evaluation of cervical lymph nodes in head and neck cancer, exhibiting high sensitivity, specificity, and accuracy. Keywords— DWI, MRI, neck lymph nodes, Head and neck cancer, metastasis. I. INTRODUCTION ead and neck cancer ranks as the sixth most common malignancy globally, accounting for approximately 6% of all cancer diagnoses and 1–2% of cancer-related deaths (1). The evaluation of cervical nodes is essential for the diagnosis and staging of malignancies, as well as for treatment planning and monitoring. While ultrasound imaging, contrast- enhanced computed tomography, and contrast-enhanced MRI facilitate the identification of enlarged cervical lymphadenopathies, none of these modalities achieves optimal accuracy (2). Ultrasound-guided fine needle aspiration biopsy (US-FNAB) of lymph nodes is a precise method; nonetheless, it is invasive, operator-dependent, and associated with a significant incidence of false-negative results. Moreover, imaging metrics including shape, size, internal architecture, extranodal diffusion, and vascular characteristics have been demonstrated to be reliable (3). Single photon emission computed tomography (SPECT) and positron emission tomography (PET) are contemporary imaging modalities that provide functional information regarding blood flow and glucose metabolism; nevertheless, they entail higher radiation exposure, are costly, have limited availability, and possess relatively low spatial resolution (4, 5). MRI, either independently or in conjunction with PET scans, offers multiple methodologies for evaluating tissue and intracellular properties in oncology, including PET imaging parameters, MRS, DTI, DKI, and DWI (ADC) (6). DWI, a non- invasive PET/MRI imaging modality, delineates tissues by the displacement motion of water molecules (Brownian motion) as determined by Apparent Diffusion Coefficient (ADC) values (7). The ADC map quantifies the extent of signal loss in biological tissue, attributable to the mobility of water molecules, which causes phase dispersion of the spin. As a result, the diffusion sequences undergo signal degradation. The ability to differentiate malignant from normal lesions using DWI/ADC in a clinical context is a recurring and significant inquiry. It has been established that benign lymph nodes display elevated ADC values compared to malignant lymph nodes. To aid clinicians in distinguishing between malignant and benign nodes, it is essential to define practical threshold values for daily application, regardless of the invasive procedures utilized to determine the nature of these nodes. The latest meta-analysis indicates that studies utilizing DWI/ADC to distinguish between benign and malignant nodes demonstrated a restricted efficacy owing to the broad spectrum of ADC thresholds and the limited sample size. This study aimed to investigate the usefulness of DWI in cervical lymph nodes and cancer and to evaluate the diagnostic utility of ADC in identifying malignant lymph nodes by determining the cutoff value with the best sensitivity and specificity. H