Correlations between intravoxel incoherent motion (IVIM) parameters and histological findings in rectal cancer: preliminary results

// Alexey Surov 1, 2 , Hans Jonas Meyer 2 , Anne-Kathrin Hohn 3 , Curd Behrmann 2 , Andreas Wienke 4 , Rolf Peter Spielmann 2 , Nikita Garnov 1 1 Department of Radiology, Martin Luther University Halle-Wittenberg, Halle, Germany 2 Department of Diagnostic and Interventional Radiology, University of Leipzig, Leipzig, Germany 3 Department of Pathology, University of Leipzig, Leipzig, Germany 4 Institute of Medical Epidemiology, Biostatistics, and Informatics, Martin Luther University Halle-Wittenberg, Halle, Germany Correspondence to: Alexey Surov, email: Alexey.Surov@medizin.uni-leipzig.de , Alex.surow@medizin.uni-halle.de Keywords: rectal cancer, diffusion weighted imaging, intravoxel incoherent motion, histopathology, tumor grading Received: November 11, 2016     Accepted: January 24, 2017     Published: February 27, 2017 ABSTRACT Our purpose was to correlate different intravoxel incoherent motion (IVIM), histopathological and clinical parameters in rectal cancer. 17 patients with histologically proven rectal cancer investigated on a 3.T device were included into the study. DWI was performed using a multi-slice single-shot echo-planar imaging sequence with b values of 0, 50, 200, 500 and 1000 s/mm. 2 A polygonal region of interest was drawn within the tumors on every b image. The following parameters were retrieved from IVIM: apparent diffusion coefficient (ADC), true diffusion (D), pseudo diffusion coefficient (D*), perfusion factor (f), and relative perfusion f·D*. In every case, cell count, nucleic areas, proliferation index KI 67, and microvessel density were estimated on histopathological specimens. Pearson’s correlation coefficient was used to analyze the association between the parameters. ADC correlated well with KI 67 index and D tended to correlate with cell count and KI 67. ADC and D tended to correlate with total nucleic area. The perfusion factor f correlated well with stained vessel area, total vessel area, and vessel count. D* and fD* correlated with mean vessel diameter. Distant metastasized tumors had higher D* and fD* values. IVIM parameter reflected different clinical and histopathological features in rectal cancer.