A pilot study on correlations between preoperative intravoxel incoherent motion MR imaging and postoperative histopathological features of rectal cancers

Background: To explore the role of intravoxel incoherent motion (IVIM) magnetic resonance (MR) imaging in predicting the histopathological features of rectal cancers preoperatively. Methods: Forty-six patients with a diagnosis of rectal cancer through endoscopic biopsy were prospectively enrolled and underwent IVIM MR imaging (12 b values: 0-1,200 s/mm(2)) before surgery. Apparent diffusion coefficient (ADC), pure diffusion coefficient (D), perfusion-related incoherent microcirculation (D*) and perfusion fraction (f) values of the lesions were obtained and compared among rectal cancers with different histopathological features, including maximum diameter, pathological type, differentiation degree, TNM stage, lymphovascular and neural invasion status. Results: The f and D* values of rectal cancers with lymphovascular invasion (LVI) were significantly higher than those without LVI (P = 0.034, 0.037, respectively). And the LVI rate differed significantly among rectal cancers with different pN stages (P = 0.003). Conclusions: We demonstrated that the f value derived from IVIM MR imaging might be useful to predict LVI status of rectal cancers preoperatively, which required further confirmation in a larger cohort.