Role of Diffusion Weighted Imaging Sequences to Differentiate between Modic Change Type 1 and Spondylodiscitits

Background: Diffusion Weighted Imaging (DWI) has gained increasing use in diagnosing pathology in the spine, and is becoming valuable in the assessment of a variety of diseases including tumor and infection. Modic type 1degenerative ‌changes on conventional MR imaging can mimicor suggest infection, leading to ‌additional costly and sometimes invasiveinvestigations.‌Aims: To study the role of DWI in uncertain (doubtful) cases with overlapping ‌conventional MRI signal features between Modic1 degenerativechange and ‌infectious spondylodiscitis and describe different patterns of diffusionrestriction. Patients and methods: Cross sectional study was done at radiology department of Al-Imamain Al Kadhimain Medical city.Studywas done from October 2021 ‌and November 2022 with a convenient sample of 53patients. The patients were ‌sent for spinalMRI and had clinically suspected to have Modic type 1change or ‌discitis.Conventional MRI with sagittal DWI was done for all patients. Patients ‌were classified as either had Modictype 1 degenerative changes or discitis. Results: Thirty-six of patients (68%) were Modic type 1 degenerative changes and 17 (32%) patients had spondylodiscitis.The definite Claw sign was found ‌among 19(52.8%) of the patients, probableClaw sign found among 10(27.8%), ‌questionable Claw sign foundamong 6(16.7%)of the patients, while none of ‌those (0%) of those with spondylodiscitis had thesesigns. Diffused Abnormal ‌DWI (negative claw sign) signal found among 1(2.8%)of those with Modic 1 in ‌comparison to 3(16.7%) of those with discitis.‌Conclusion: DWI is useful for differentiating Modic type 1 degenerative changes ‌andinfectious spondylodiscitis. The claw sign is useful and accurate sign for ‌distinguishing Modic type 1 endplatedegenerative changes from spondylodiscitis.‌Key words: Diffusion Weighted Imaging, Modic Change, Spondylodiscitits.‌