Evaluation of rectal carcinoma response to neoadjuvant treatment using multiparametric imaging on 3T MRI scanner
Abstract
Aim: Evaluation of capability of multiparametric MR imaging in the prediction and evaluation of response to neoadjuvant chemoradiotherapy in locally advanced rectal carcinoma. Metod: We performed a retrospective analysis of multiparametric MRI examinations on 3T scanner and histological findings in 22 patients before and after neoadjuvant chemoradiotherapy.
In addition to the standard noncontrast and postcontrast MRI, the examinations included dynamic contrast-enhanced scans and diffusion-weighted images. Results: The assessment of tumor staging using only noncontrast MRI and nondynamic postcontrast scans has a tendency to overestimate the extent of tumors in the group of neoadjuvant treatment responders.
If we compared pharmakokinetic parameters and apparent diffusion coefficient (ADC) values from the baseline MRI within the group of responders and nonresponders, we find significantly lower value for the parameter V in the group of responders (p = 0,013), differencies in all other parameters were nonsignificant. Comparison of the results of the baseline examination with examination after treatment separately in the group of responders and nonresponders, we found statistically significant changes in values ADC (p < 0,001), Kttims (p < 0,001), Kp (p = 0,002) and iAUC (p = 0,048) in the group of responders.
In the group of non-responders is a statistically significant difference only in the parameter V (p = 0,027). Conclusion: From our research it is noticeable that although MRI is the most sensitive method for evaluation of the advanced stages of rectal cancer, is impossible to use it for prediction of the therapeutic effect in patients before neoadjuvant chemoradio-therapy It seems, that based of the comparison of results of pharmakokinetic analysis and ADC values from baseline and post-treatment MRI, it is possible to select patients with good response to the treatment, that can be candidates for less radical surgery or Watch and Wait protocol.