Quantitative Measurement of Blood Flow Using Perfusion CT for Assessing Clinicopathologic Features and Prognosis in Patients with Rectal Cancer

PURPOSE: The ability to evaluate clinicopathologic features and prognosis before surgery by contrast-enhanced CT would be valuable for managing rectal cancer. This study was designed to evaluate the clinical usefulness of perfusion CT in patients with rectal cancer before surgery. METHODS: Forty-four consecutive patients (27 men, 17 women; median age, 63.6 years) with rectal cancer underwent perfusion CT before surgery. We retrospectively investigated the correlations between tumor blood flow generated by perfusion CT and clinicopathologic features. RESULTS: There was a significant correlation between blood flow and wall invasion (P = 0.04). Well-differentiated tumors showed significantly higher blood flow than moderately differentiated tumors (P = 0.03). There was a significant tendency for tumors with low blood flow to show lymph node metastasis (P = 0.0005), vascular invasion (P = 0.004), lymphatic invasion (P = 0.04), and distant metastasis (P = 0.0005). For blood flow, accuracy was 75% for detection of tumors with lymph node metastasis if the cutoff point was set at 55 ml/100 g per minute. Patients with high blood flow tumors survived significantly longer than those with low blood flow tumors (P = 0.002). CONCLUSIONS: Blood flow of rectal cancers may be useful to evaluate pathologic features and prognosis before surgery.