ABSTRACT
OBJECTIVE: To investigate the diagnostic value of CT colonography for the detection of colorectal polyps. MATERIALS AND METHODS: From December 2004 to December 2005, 399 patients underwent CT colonography and follow-up conventional colonoscopy. We excluded cases of advanced colorectal cancer. We retrospectively analyzed the CT colonography findings and follow-up conventional colonoscopy findings of 113 patients who had polyps more than 6 mm in diameter. Radiologists using 3D and 2D computer generated displays interpreted the CT colonography images. The colonoscopists were aware of the CT colonography findings before the procedure. RESULTS: CT colonography detected 132 polyps in 107 of the 113 patients and conventional colonoscopy detected 114 colorectal polyps more than 6 mm in diameter in 87 of the 113 patients. The sensitivity of CT colonography analyzed per polyp was 91% (41/45) for polyps more than 10 mm in diameter and 89% (101/114) for polyps more than 6 mm in diameter. Thirteen polyps were missed by CT colonography and were detected on follow-up conventional colonoscopy. CONCLUSION: CT colonography is a sensitive diagnostic tool for the detection of colorectal polyps and adequate bowel preparation, optimal bowel distention and clinical experience are needed to reduce the rate of missing appropriate lesions.
Subject(s)
Colonic Polyps/diagnosis , Colonography, Computed Tomographic/methods , Colorectal Neoplasms/diagnosis , Adult , Aged , Aged, 80 and over , Colonoscopy/methods , Contrast Media/administration & dosage , False Negative Reactions , False Positive Reactions , Follow-Up Studies , Humans , Image Processing, Computer-Assisted , Imaging, Three-Dimensional , Iohexol/analogs & derivatives , Middle Aged , Observer Variation , Predictive Value of Tests , Radiographic Image Enhancement/methods , Retrospective Studies , Sensitivity and SpecificityABSTRACT
PURPOSE: The purpose of this article is to assess the correlation between contrast enhancement on CT and the tumor reduction ratio in small cell carcinoma of the lung after first-line chemotherapy. MATERIALS AND METHODS: Twenty-eight patients with small cell carcinoma of lung underwent preenhancement and postenhancement CT scans before and after first-line chemotherapy, followed by second-line chemotherapy in 7 patients who had relapsed. The authors retrospectively analyzed the correlation between the tumor reduction ratio and the CT numbers of contrast enhancement in each case by multiple regression analysis using SPSS. RESULTS: The mean tumor-reduction ratio was 58.2 +/- 43.2% after first-line chemotherapy, and the mean CT enhancement was 33.2 +/- 11.0 Hounsfield units (HU). The correlation coefficient between the tumor reduction ratio and the CT numbers of contrast enhancement was 0.57 (r = 0.32), and p value was < 0.002. After chemotherapy, more than 90% tumor reduction was seen in 11 patients. They revealed an average 41.9 +/- 7.6 HU tumor enhancement. Less than 50% tumor reduction was seen in 10 patients. They revealed an average 26.2 +/- 7.9 HU tumor enhancement. If these criteria of 30 HU contrast enhancement and 80% tumor reduction ratio were applied as a guide for chemotherapy response, the sensitivity, specificity, positive predictive value, and negative predictive value would be calculated as 85.7%, 84.6%, 85.7%, and 84.6%, respectively. CONCLUSION: In small cell carcinoma of the lung, it is statistically proven that the more enhanced tumor on CT, the better response to chemotherapy. Tumor enhancement of 30 HU is a suggestive guide for chemotherapy response in patients with small cell carcinoma.
