The value of diffusion kurtosis magnetic resonance imaging for assessing treatment response of neoadjuvant chemoradiotherapy in locally advanced rectal cancer.

ABSTRACT

OBJECTIVES: To evaluate the feasibility and value of diffusion kurtosis (DK) imaging in assessing treatment response to neoadjuvant chemoradiotherapy (CRT) in patients with locally advanced rectal cancer (LARC). METHODS: Forty-one patients were included. All patients underwent pre- and post-CRT DCE-MRI on a 3.0-Tesla MRI scanner. Imaging indices (D app , K app and ADC values) were measured. Change value (∆X) and change ratio (r∆X) were calculated. Pathological tumour regression grade scores (Mandard) were the standard reference (good responders pTRG 1-2; poor responders pTRG 3-5). Diagnostic performance was compared using ROC analysis. RESULTS: For the pre-CRT measurements, pre-D app-10th was significantly lower in the good responder group than that of the poor responder group (p = 0.036). For assessing treatment response to neoadjuvant CRT, pre-D app-10th resulted in AUCs of 0.753 (p = 0.036) with a sensitivity of 66.67 % and a specificity of 77.78 %. The r∆D app had a relatively high AUC (0.859) and high sensitivity (100 %) compared with other image indices. CONCLUSIONS: DKI is feasible for selecting good responders for neoadjuvant CRT for LARC. KEY POINTS • LARC responded well after neoadjuvant chemoradiotherapy with lower pre-D app-10th . • LARC responded well with greater increases in mean ADC and D app . • The change ratio of D app (r∆D app ) had a relatively better diagnostic performance.