نقش تزریق IVIM و DCE در پیش بینی پاسخ در بیماران مبتلا به سرطان رکتوم پس از شیمی درمانی

Despite advances in multi-modality treatment strategies for locally advanced rectal cancer and improvements in loco-regional control, there is still a considerable variation in response to neo-adjuvant chemo-radiotherapy (CRT). Accurate prediction of response to neo-adjuvant CRT would enable early stratification of management according to good responders and poor responders, in order to adapt treatment to improve therapeutic outcomes in rectal cancer. Clinical studies in IVIM and dynamic contrast enhanced (DCE) MRI have shown promising results for the prediction of therapeutic response in rectal cancer. Intravoxel incoherent motion DWI (IVIM-DWI) is on the basis of a bi-exponential model with the ability to quantitate the pure diffusion motion and perfusion-related motion of water molecules without the administration of gadolinium agent. Thus, IVIM-DWI is theoretically superior to conventional DWI in providing the information of tumor microenvironment related to treatment effect. Indeed, pretreatment IVIM-DWI is reportedly more powerful than traditional DWI in prediction response of LARC to nCRT. However, the performances of the baseline IVIM-DWI parameters on predicting CRT are conflicting across prior investigations on LARC. A possible reason is that the findings in the above-mentioned reports were based on the mean or percentiles values of IVIM-DWI parameters, which may not adequately reflect intratumoral heterogeneity, a feature closely associated with therapeutic re