Diagnostic performance of minimum and mean apparent diffusion coefficient parameters in evaluation of resectable rectal cancer

Abstract

Objective: To investigate the diagnostic correlations between MinADC and MeanADC values of resectable rectal cancer with tumoral histopathological features.

Methods: This cross-sectional study included 52 rectal cancer patients that were subjected to preoperative MRI and DWI. MeanADC and MinADC values were calculated and correlated with clinicopathological characteristics.

Results: MeanADC and MinADC values correlated statistically significant with tumor histological grade(MeanADC: t= 2.494, p = 0.016; MinADC: t = 2.857, p = 0.006). MeanADC correlated significantly with T-classification (MeanADC: t = 2.678, p = 0.010)and with perineural invasion(MeanADC: t = 2.525, p = 0.015). MeanADC and MinADC statistically correlated significantly with extramural vascular invasion(MeanADC: t = 2.023, p = 0.048; MinADC: t = 2.055, p = 0.045) and CRM invasion MinADC showed statistically significant correlation(MinADC: t=2.657, p=0.011). MinADC values showed higher diagnostic efficacy in discriminating well vs poor and moderately differentiated rectal cancer than MeanADC values, with threshold value of 0.55x10-3mm2/s(sensitivity, 58%; specificity, 90%)but MeanADC values showed higher diagnostic efficacy in discriminating extramural vascular invasion than MinADC values with threshold value of 1.21x10-3mm2/s(sensitivity, 77.8%; specificity, 76.7%).

Conclusion: Pretreatment combination of mean and minimum ADC values used as a non-invasive parameter to evaluate the aggressiveness of rectal cancer.