The purpose of this evidence-based review was to evaluate the current status of the performance of CT colonography and clinical indications in Japan. Japanese National CT Colonography Trial and UMIN6665 study revealed that the accuracy of the detection of colorectal neoplasia was as high as colonoscopy performed by board-certified colonoscopists. Interpretation by gastroenterologists and radiologists was accurate for the detection of polypoid neoplasms, but less so for nonpolypoid neoplasms. UMIN9278 study showed low-dose CTC with iterative reconstruction reduced the radiation dose by 75% (mean effective radiation exposure, 0.46mSv) without image quality degradation compared to routine-dose CTC with filtered back projection. UMIN9278 study revealed colonic distention was significantly improved by automated carbon dioxide insufflation, but not by the administration of hyoscine butylbromide. When colonoscopy is contraindicated or not possible, CT colonography is an acceptable and equally sensitive alternative for patients as a diagnostic test for colorectal neoplasia. The combination of sigmoidoscopy and barium enema is also acceptable.

View full abstract

AIM: Chronic active gastritis and mucosal atrophy develop from Helicobacter pylori (H. pylori)-infected gastric mucosa. Therefore, to diagnose H. pylori infection with an X-ray examination, it is important to recognize the gastritis and mucosal atrophy of X-ray findings. The present study measured the efficacy of our training based on X-ray image-reading of chronic active gastritis and mucosal atrophy.
SUBJECTS and METHODS: The subjects were 38 radiological technologists and doctors engaged in gastric cancer X-ray screening (31 were radiological technologists). To verify diagnostic accuracy, we used X-ray images with H. pylori IgG antibody serum titer. The diagnostic accuracy was compared before and after the training session.
RESULTS: Our results indicated that the sensitivity and the specificity of diagnosis pre-training were 76.3% and 82.9%. After the training, these values increased to 93.2% and 89.7%, respectively (P<0.05).
CONCLUSION: We confirmed the effectiveness of our X-ray image-reading training for diagnosing H. pylori infection.

View full abstract

Although there are some difficulties in the management of the ABC classification system of gastric cancer risk assessment, there have been few systematic reports on them. We evaluated the 5-year follow-up conditions of the examinees who had undergone the ABC classification system. We reviewed the follow-up status in our and other institutions for 706 examinees (427 of Group A, 202 of Group B, 68 of Group C and 9 of Group D) who had undergone the classification at our institution in 2010. We investigated other institutions by mail. The results were as follows; 1) the rate of collecting questionnaires was 46% and was low; 2) the rate of examinees who underwent endoscopy or X-ray examinations within the first one year was 80∼90% and was high in all groups; 3) But it decreased to 50∼60 % after the second year, and did not increase after the third year. Based on these results and the importance of the management, we think that we should encourage examinees who had undergone the ABC classification system to receive gastric cancer screening examinations after the third year. Furthermore, we have begun a randomized control trial to evaluate the efficacy of encouraging examinees to have screening tests.

View full abstract

Aim: There have been few reports on interval colorectal cancer in persons undergoing screening by the immunochemical fecal occult blood test (iFOBT). We investigated the characteristics of interval colorectal cancer among participants in an iFOBT screening program. Methods: Interval colorectal cancer was defined as invasive cancer diagnosed by another test within the next fiscal year after a negative iFOBT, while positive colorectal cancer was defined as invasive cancer diagnosed by screening or another test within the next fiscal year after a positive iFOBT. The gender, age, screening history, stage, location, and histological features were compared between interval cancer and positive cancer, and cluster analysis was performed to classify interval cancer. Medical records of the subjects were linked with data on confirmed colorectal cancers from the Gunma Cancer Registry to identify interval and positive cancers. Results: Among 27,799 persons undergoing iFOBT, 10 interval cancers and 69 positive cancers were detected. Ninety percent of interval cancers were detected by annual screening. Persons with interval cancer were more likely to be female and elderly than that those with positive cancer. Interval cancers were significantly more likely to be of higher stage and to involve the cecum compared with positive cancers. Cluster analysis identified two clusters of interval cancers, which were “Elderly Advanced Right Colon” and “Non-elderly Rectal.” Conclusions: Interval cancer showed characteristic features with respect to gender, age, location, and stage. iFOBT appears to be less effective for detecting cancer of the right colon in elderly persons.

View full abstract