title: Sub-milliSievert ultralow-dose CT colonography with iterative model reconstruction technique.
abstract: Purpose. The purpose of this study was to evaluate the technical and diagnostic performance of sub-milliSievert ultralow-dose (ULD) CT colonograpy (CTC) in the detection of colonic and extracolonic lesions. Materials and Methods. CTC with standard dose (SD) and ULD acquisitions of 64 matched patients, half of them with colonic findings, were reconstructed with filtered back projection (FBP), hybrid (HIR) and iterative model reconstruction techniques (IMR). Image noise in six colonic segments, in the left psoas muscle and aorta were measured. Image quality of the left adrenal gland and of the colon in the endoscopic and 2D view was rated on a five point Likert scale by two observers, who also completed the reading of CTC for colonic and extracolonic findings. Results. The mean radiation dose estimate was 4.1 ± 1.4 mSv for SD and 0.86 ± 0.17 mSv for ULD for both positions (p < 0.0001). In ULD-IMR, SD-IMR and SD-HIR, the endoluminal noise was decreased in all colonic segments compared to SD-FBP (p < 0.001). There were 27 small (6-9 mm) and 17 large (≥10 mm) colonic lesions that were classified as sessile polyps (n = 38), flat lesions (n = 3), or as a mass (n = 3). Per patient sensitivity and specificity were 0.82 and 0.93 for ULD-FBP, 0.97 and 0.97 for ULD-HIR, 0.97 and 1.0 for ULD-IMR. Per polyp sensitivity was 0.84 for ULD-FBP, 0.98 for ULD-HIR, 0.98 for ULD-IMR. Significantly less extracolonic findings were detected in ULD-FBP and ULD-HIR, but in the E4 category by C-RADS (potentially important findings), the detection was similar. Conclusion. Both HIR and IMR are suitable for sub-milliSievert ULD CTC without sacrificing diagnostic performance of the study.
authors.affiliation: Department of Radiology, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague , Prague , Czech Republic.
authors.forename: Lukas
authors.initials: L
authors.lastname: Lambert
authors.affiliation: Department of Imaging Methods, St. Anne's University Hospital in Brno , Brno , Czech Republic.
authors.forename: Petr
authors.initials: P
authors.lastname: Ourednicek
authors.affiliation: First Department of Surgery, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague , Prague , Czech Republic.
authors.forename: Jan
authors.initials: J
authors.lastname: Briza
authors.affiliation: Clinical Science & Application Computed Tomography, Philips Healthcare , Best , The Netherlands.
authors.forename: Walter
authors.initials: W
authors.lastname: Giepmans
authors.affiliation: Department of Radiology, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague , Prague , Czech Republic.
authors.forename: Jiri
authors.initials: J
authors.lastname: Jahoda
authors.affiliation: Department of Imaging Methods, St. Anne's University Hospital in Brno , Brno , Czech Republic.
authors.forename: Lukas
authors.initials: L
authors.lastname: Hruska
authors.affiliation: Department of Radiology, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague , Prague , Czech Republic.
authors.forename: Jan
authors.initials: J
authors.lastname: Danes
keywords: CT colonography; Iterative reconstruction technique; Low-dose; Polyp