MDCTによる肝臓癌スクリーニング検査時の至適設定スライス厚の検討 Evaluation of Appropriate Slice Thickness Setting in Multidetector-row CT Examinations for Screening of Liver Cancer

In this study, we evaluated clinical images to determine appropriate settings for slice thickness in screening examinations for hepatocellular carcinoma and metastatic liver cancer, which are frequently performed in abdominal CT. The clinical images of 15 cases screened for hepatocellular carcinoma and 15 cases screened for metastatic liver cancer were evaluated. The evaluation was visually performed by three abdominal radiologists, and the sensitivity and specificity of each slice thickness were calculated. Results: differences in sensitivity and specificity were not found between slice thicknesses of 2.5 mm and 5.0 mm; however, sensitivity and specificity were low, and confidence was also low at a 10.0 mm slice thickness. Furthermore, when a 5.0 mm slice thickness was adopted, it was shown that radiation dose in limited parts could be reduced greatly to a noise level that compared equally with a study in which a 2.5 mm slice thickness was adopted in another evaluation. Therefore, the objective could be achieved by using a slice thickness of about 5.0 mm in multidetector-row CT examinations for the screening of liver cancer, while controlling patient dose to a minimum.

In this study, we evaluated clinical images to determine appropriate settings for slice thickness in screening examinations for hepatocellular carcinoma and metastatic liver cancer, which are frequently performed in abdominal CT. The clinical images of 15 cases screened for hepatocellular carcinoma and 15 cases screened for metastatic liver cancer were evaluated. The evaluation was visually performed by three abdominal radiologists, and the sensitivity and specificity of each slice thickness were calculated. Results: differences in sensitivity and specificity were not found between slice thicknesses of 2.5mm and 5.0mm ; however, sensitivity and specificity were low, and confidence was also low at a 10.0mm slice thickness. Furthermore, when a 5.0mm slice thickness was adopted, it was shown that radiation dose in limited parts could be reduced greatly to a noise level that compared equally with a study in which a 2.5mm slice thickness was adopted in another evaluation. Therefore, the objective could be achieved by using a slice thickness of about 5.0mm in multidetector-row CT examinations for the screening of liver cancer, while controlling patient dose to a minimum.