Adenomatous Polyposis Coli ; genetics ; pathology ; Colonic Neoplasms ; classification ; genetics ; pathology ; Colorectal Neoplasms, Hereditary Nonpolyposis ; diagnosis ; genetics ; DNA Glycosylases ; metabolism ; Humans ; Intestinal Polyps ; pathology ; Lymphatic Metastasis ; Neoplasm Staging ; Neuroendocrine Tumors ; classification ; pathology ; Precancerous Conditions ; pathology ; Rectal Neoplasms ; classification ; genetics ; pathology ; World Health Organization

PURPOSE: To investigate the correlations between parameters of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and prognostic factors in rectal cancer. MATERIALS AND METHODS: We studied 29 patients with rectal cancer who underwent gadolinium contrast-enhanced, T1-weighted DCE-MRI with a three Tesla scanner prior to surgery. Signal intensity on DCE-MRI was independently measured by two observers to examine reproducibility. A time-signal intensity curve was generated, from which four semiquantitative parameters were calculated: steepest slope (SLP), time to peak (Tp), relative enhancement during a rapid rise (Erise), and maximal enhancement (Emax). Morphologic prognostic factors including T stage, N stage, and histologic grade were identified. Tumor angiogenesis was evaluated in terms of microvessel count (MVC) and microvessel area (MVA) by morphometric study. As molecular factors, the mutation status of the K-ras oncogene and microsatellite instability were assessed. DCE-MRI parameters were correlated with each prognostic factor using bivariate correlation analysis. A p-value of <0.05 was considered significant. RESULTS: Erise was significantly correlated with N stage (r=-0.387 and -0.393, respectively, for two independent data), and Tp was significantly correlated with histologic grade (r=0.466 and 0.489, respectively). MVA was significantly correlated with SLP (r=-0.532 and -0.535, respectively) and Erise (r=-0.511 and -0.446, respectively). MVC was significantly correlated with Emax (r=-0.435 and -0.386, respectively). No significant correlations were found between DCE-MRI parameters and T stage, K-ras mutation, or microsatellite instability. CONCLUSION: DCE-MRI may provide useful prognostic information in terms of histologic differentiation and angiogenesis in rectal cancer.
Adult ; Aged ; Aged, 80 and over ; Cell Differentiation ; Contrast Media/*pharmacology ; DNA Mutational Analysis ; Female ; Gadolinium/pharmacology ; Genes, ras ; Humans ; Magnetic Resonance Imaging/*methods ; Male ; Microcirculation ; Microsatellite Instability ; Middle Aged ; Neoplasm Staging ; Neovascularization, Pathologic ; Prognosis ; Rectal Neoplasms/*diagnosis/genetics/*pathology ; Retrospective Studies ; Time Factors