Ultra Low Dose chest CT (ULD-CT) is an unenhanced CT examination acquired at a radiation dose lowered to that of a PA and lateral chest x-ray, i.e. a DLP < 20mGy.cm / Effective Dose <0.3mSv. Its image quality is degraded, yet remains diagnostic in many clinical scenarios, with a rapidly growing interest in the literature. Established indications of ULD-CT are therefore increasing, and its non-inferiority compared to the reference “full dose” chest CT iscurrently demonstrated for: the detection of solid nodules the screening of asbestos-related...

ULD CT examinations 25 normal or subnormal examinations were selected by one chest radiologist from a previous IRB-approved prospective study. All 25 patients underwent two successive unenhanced chest CT acquisitions on a second-generation 320-row scanner (Aquilion One Vision Edition, Toshiba Medical Systems, Japan) with: one standard "full dose" acquisition: 120kV and auto-mA (80-700) one ULD acquisition: 135kV and 10mA both acquired with a pitch of 0.813, a tube rotation of 0.275sec, a collimation of 0.5*80mm and reconstructed at a slice-thickness of 1mm every 0.8mm with...

Population CT examinations of 15 men and 10 women were analyzed. Mean age of patients was 64.7±11.6 years old (range 35-91). Mean BMI was26.2 ±4.3 kg/m² (range 17-33). Radiation Dose Mean Dose Length Product of the ULD acquisition was 15.6±1.9mGy.cm (Effective Dose: 0.22mSv) versus 219±108mGy.cm (ED: 3mSv) for the full dose acquisition. Quantitative evaluation A PSNR increase was demonstrated for all denoised ULD images, with a maximum obtained at a β coefficient of 4.4±2.8, i.e. for β2 or β5 denoised sets. The mean PSNR increase...

We have demonstrated that NLM image-domain denoising is quantitatively and qualitatively efficient in improving ULD unenhanced chest CT, with increase of bothsubjective as well as objective image quality when using a β coefficient of 1-2. The difference in the optimal β coefficient between the qualitative and the quantitative evaluation (1-2 versus 4) could be explained by two points : the reference full dose acquisition is not rigorouslynoiseless, and therefore the PSNR calculation is, to some extent,biased. the registration is not strictly perfect, and therefore more...

MickaëlOHANA Email me !orFollow me onTwitter! AissamLABANI Mi-YoungJEUNG Claire LUDES CatherineROY Department of Cardiovascular and Chest Diagnostic Imaging Nouvel Hôpital Civil Strasbourg University Hospital France Christophe COLLET Fabrice HEITZ François ROUSSEAU Vincent NOBLET MIV - Department of Models, Images & Vision iCube Laboratory - Telecom Physics Strasbourg Illkirch France

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