Correlation of Standard Diffusion-Weighted Imaging and Diffusion Kurtosis Imaging With Distant Metastases of Rectal Carcinoma

Purpose: To investigate the correlation of standard diffusion-weighted imaging (DWI) and diffusion kurtosis imaging (DKI) with distant metastases of rectal carcinoma. Materials and Methods: Fifty-eight patients with rectal carcinoma (27 with distant metastasis and 31 with no metastasis) were included in this study. The apparent diffusion coefficient (ADC) value from standard DWI (b values of 0 and 1000 sec/mm(2)), D-app, and K-app from DKI (b values of 0, 700, 1400, and 2000 sec/mm(2)) were acquired with a 3.0T magnetic resonance imaging (MRI) scanner. These quantitative parameters were calculated from the entire tumors. Receiver operating characteristic curve analyses were conducted to assess the utility for discrimination of tumor with distant metastasis and those without metastasis. Parameters were compared using the independent-samples t-test. Results: The histogram metrics 10th percentile of D-app (Dapp-10th) and ADC values (ADC(10th)) were significantly lower in the distant metastasis group than those without metastasis (972.5 +/- 118.8 vs. 1121.3 +/- 133.8x10(-6) mm(2)/s, P=0.03; 809.2 +/- 67.1 vs. 856.2 +/- 72.1x10(-6) mm(2)/s, P=0.03). Dapp-10th showed relatively higher area under the curve (AUC) (0.856 vs. 0.669, P=0.024), and higher specificity (100% vs. 68%) than ADC(10th) did for differentiation of lesions with distant metastasis from those without metastasis. Conclusion: DKI was relatively better than standard DWI in discriminating rectal carcinoma with distant metastasis from those without metastasis.