Evaluation of Deep Vein Thrombosis With Reduced Radiation and Contrast Material Dose at Computed Tomography Venography.
Circ J. 2012 Jul 11;
Authors: Oda S, Utsunomiya D, Funama Y, Shimonobo T, Namimoto T, Itatani R, Hirai T, Yamashita Y
Background:?Computed tomography venography (CTV) is clinically useful and widely available for the detection of deep vein thrombosis. Disadvantages of CTV are the need for a larger amount of i.v. contrast material (CM) and radiation exposure. A low-tube-voltage technique with iterative reconstruction may overcome this problem. The aim of this study was to investigate the effects of hybrid iterative reconstruction (HIR) on image quality at low-tube-voltage CTV. Methods and Results:?Forty patients (26 women, 14 men; mean age, 59.2±18.3 years) underwent CTV under an 80- or 120-kV protocol (CT dose index volume=10.3mGy vs. 14.9mGy, CM dose=540mgI/kg vs. 690mgI/kg) on a 64-detector CT. Quantitative parameters (ie, venous attenuation, image noise, and contrast-to-noise ratio [CNR]) were calculated and the image quality was scored on a 4-point scale. In step 1, the 80- and 120-kV protocols were compared under filtered back projection (FBP). In step 2, the 80-kV protocol with HIR was compared with the 120-kV protocol with FBP. In step 1, the visual scores were significantly higher under the 120-kV protocol; there was no significant difference in CNR between the protocols. In step 2, CNR was significantly higher under the 80-kV protocol with HIR than the 120-kV protocol with FBP. The visual scores of the 2 protocols were comparable. Conclusions:?The 80-kV CTV with HIR allows for a reduction in the radiation dose by 30% and the CM dose by 20% without image quality degradation.
PMID: 22784997 [PubMed - as supplied by publisher]