Role of Diffusion MRI Study in Assessment of Colorectal Tumor Response after Chemoradiotherapy

Ahmed, Khaled Abd El-Baky; Elrakhawy, Mohamed Magdy; El Shahat, Ahmed Mohamed; Gohar, Omnia Hassan; Abo Shanab, Waleed Said

doi:10.21608/muj.2024.279453.1166

Role of Diffusion MRI Study in Assessment of Colorectal Tumor Response after Chemoradiotherapy

Document Type : Research project

Authors

¹ Faculty of Medicine – Port said University

² Faculty of medicine Mansoura University

³ Diagnostic Radiology Department Ministry of Health Specialized Damietta Hospital

⁴ Surgical Oncology Department, Ministry of Health, Damietta Oncology Institute

⁵ Assistant Professor of diagnostic radiology, faculty of medicine, Port Said University

10.21608/muj.2024.279453.1166

Abstract

Objective: To address the role of DWI-MRI in measurements of ADC [pre, post CRT] for pre-treatment prediction of outcome and early detection of response in patients having CRC
Methods: study was conducted on 40 cases selected from patients presented to Damietta Oncology Institute with CRC to whom DWI-MRI examinations of lower abdomen before and after CRT were performed. All patients underwent histopathological assessment , which serve as the benchmark for local staging following CRT. The studied cases were classified into 3 groups according to response to CRT: stable disease (no response to treatment), partial response (decrease of at least one level in T or N staging in comparison to baseline MRI), and complete response (disappearance of any evidence of tumor cells in surgical specimen).
Results: For detection of CRC; diagnostic accuracy of conventional MRI (66.5%), sensitivity (69%) and specificity (63.6%). DWI MRI showed diagnostic accuracy (80%), sensitivity (72.7%) and specificity (82.7%). optimal ADC post CRT cutoff value of 1.18 × 10−3 mm2/s revealed best accuracy (92.5%), sensitivity (82%), specificity (96.6%) in assessing tumor response after CRT. ADC value is significantly lower in poorly differentiated tumors.
Conclusion: ADC exhibits significant utility in assessing the response of tumors following treatment, metastatic nodesassessment . Hence, ADC facilitates the development of a suitable treatment strategy. In patients having locally advanced colorectal cancer, utilization of DWI with ADC value in conjunction with conventional MRI demonstrates superior accuracy in tumor grade correlation, staging and evaluating response to neo-adjuvant CRTcompared to exclusive reliance on conventional MRI.

Keywords