Value of dynamic contrast-enhanced MRI in the diagnosis of acute radiation-induced rectal injury in patients with rectal cancer: A comparison with endoscopy

AbstractObjectives To investigate the diagnostic value of dynamic contrast-enhanced MRI (DCE-MRI) quantitative parameters in acute radiation-induced rectal injury (RRI) among patients with rectal cancer. Methods This retrospective study included patients confirmed to rectal cancer who underwent rectal MRI (including a DCE-MRI sequence) and endoscopy after neoadjuvant chemoradiotherapy from November 2014 to July 2022. The enrolled patients were divided into an acute RRI group and a non-acute RRI group based on Vienna rectoscopy score. Two radiologists independently measured DCE-MRI quantitative parameters (including the forward volume transfer constant Ktrans, rate constant kep, and fractional extravascular extracellular space volume ve) and thickness of rectal wall. Receiver operating characteristic curve analysis was performed to analyze statistically significant parameters. Results Forty-nine patients (median age, 58 years; interquartile range, 14 years; 34 men) were enrolled, 28 of whom were in the acute RRI group. Ktrans in patients with acute RRI was significantly lower compared to those without acute RRI (0.049 min−1 vs 0.107 min−1; P Ktrans was 0.80. With a Ktrans cutoff value of 0.079 min−1, the sensitivity and specificity were 93 % and 67 %, respectively. Conclusion Ktrans demonstrated moderate performance in diagnosing acute RRI, providing a non-invasive and objective basis for managing and treating rectal cancer patients with acute RRI.