Third-generation dual-source computed tomography of the abdomen: comparison of radiation dose and image quality of 80kVp and 80/150kVp with tin filter

Abstract

ObjectiveTo compare the radiation dose, objective and subjective image quality, and diagnostic performances of 80 kVp and 80/150 kVp with tin filter (80/Sn150 kVp) computed tomography (CT) in oncology patients. MethodsOne hundred forty-five consecutive oncology patients who underwent third-generation dualsource dual-energy CT of the abdomen for evaluation of malignant visceral, peritoneal, extraperitoneal, and bone tumor were retrospectively recruited. Two radiologists independently reviewed each observation in 80 kVp CT and 80/Sn150 kVp CT. Modified line-density profile of the tumor and contrast-to-noise ratio (CNR) were measured. Diagnostic confidence, lesion conspicuity, and subjective image quality were calculated and compared between image sets. ResultsModified line-density profile analysis revealed higher attenuation differences between the tumor and the normal tissue in 80 kVp CT than in 80/Sn150 kVp CT (127 vs. 107, P = 0.05).The 80 kVp CT showed increased CNR in the liver (8.0 vs. 7.6) and the aorta (18.9 vs. 16.3) than the 80/Sn150 kVp CT. The 80 kVp CT yielded higher enhancement of organs (4.9 ± 0.2 vs. 4.7 ± 0.4, P < 0.001) and lesion conspicuity (4.9 ± 0.3 vs. 4.8 ± 0.5, P = 0.035) than the 80/Sn150 kVp CT; overall image quality and confidence index were comparable. The effective dose reduced by 45.2% with 80 kVp CT (2.3 mSv ± 0.9) compared to 80/Sn150 kVp CT (4.1 mSv ± 1.5). ConclusionsThe 80 kVp CT performed similar or better than 80/Sn150 kVp CT for abdominal tumor evaluation with 45.2% radiation dose reduction in oncology patients. Hepatobiliary 25 (17.2) Gastro-small bowel 24 (16.5) Breast 17 (11.7) Genitourinary 14 (9.7) Bronchial 8 (5.5) Others 10 (6.9) Reference standard Liver MRI and PET/CT 48 (33.1) PET/CT 37 (25.5) Pelvis MRI and PET/CT 18 (12.4) PET/CT and spine MRI 17 (11.7) Liver MRI, PET/CT, and surgery 15 (10.3) Liver MRI, PET/CT, and spine MRI 7 (4.8) Liver MRI and surgery 3 (2.0)Note. Data are presented as number (%), unless indicated otherwise.