Introduction: In India newly diagnosed Rectal cancer cases in 2021 were 15,8881. Multiparametric MRI has become mandatory for evaluation of patients newly diagnosed with rectal cancer because it can help accurately stage the disease, impact the choice to give neoadjuvant therapy or proceed with up-front surgery, and even direct surgical dissection planes2.  Multiparametric MRI of the rectum refers to addition of diffusion and perfusion-weighted sequences to conventional rectal MRI. This technique, which is focused on tumor biology, is relatively new3-5. There are only limited number of articles on this topic in the literature in North India. As such Dynamic contrast enhanced MRI and Diffusion weighted imaging remains an active area of ongoing research. Multiparametric MRI has the potential to evaluate and predict circumferential resection margin, extramural invasion and extramural venous invasion with high accuracy. In addition, studies have shown that it is a reproducible technique with high specificity (92%) for predicting a negative circumferential resection margin (CRM), depth of invasion beyond muscularis propria and relationship of the tumor with the CRM6. Characterization of lymph nodes based on morphologic criteria along with multiparametric imaging may help in diagnosing metastatic lymph nodes.  

Results: Total 40 patients were enrolled in this study. Dynamic contrast enhanced and diffusion weighted sequences gave most significant results, where the exact localization of tumor was done. In our study, pre NACRT patients  DWI is 95% sensitive and DCE MRI is 97.5% sensitive, in  post NACRT patients T1 is 60% sensitive,  oblique axial T2 is 70% sensitive,  DWI is 82.5% sensitive in diagnosing the tumor and 90% with DCE MRI. As per the study conventional sequences in post NACRT patients are less sensitive in T staging due to the post NACRT fibrosis and necrosis.

Conclusion: Among conventional sequences oblique axial T2 weighted imaging with minimal spacing and slice thickness along with post contrast T1 images allow the most accurate assessment of residual tumour. In novel sequences DWI and dynamic contrast imaging also shows accurate results and should be added to routine sequences if possible.