Detection of pulmonary nodules: a clinical study protocol to compare ultra-low dose chest CT and standard low-dose CT using ASIR-V

Marie Ludwig; Emilie Chipon; Julien Cohen; Emilie Reymond; Maud Medici; Anthony Cole; Alexandre Moreau Gaudry; Gilbert Ferretti

doi:10.1136/bmjopen-2018-025661

Detection of pulmonary nodules: a clinical study protocol to compare ultra-low dose chest CT and standard low-dose CT using ASIR-V

BMJ Open. 2019 Aug 15;9(8):e025661. doi: 10.1136/bmjopen-2018-025661.

Authors

Marie Ludwig^{1

2}, Emilie Chipon^{3

4}, Julien Cohen^{1

2}, Emilie Reymond¹, Maud Medici^{3

4}, Anthony Cole^{1

2}, Alexandre Moreau Gaudry^{3

4}, Gilbert Ferretti^{1

2}

Affiliations

¹ Service de radiologie et imagerie médicale, pôle imagerie, Centre Hospitalier Universitaire Grenoble Alpes, Grenoble, France.
² Faculte de Medecine, Universite Grenoble Alpes, La Tronche, France.
³ CIC 1406, INSERM, Grenoble, France.
⁴ Pôle recherche, Centre Hospitalier Universitaire Grenoble Alpes, Grenoble, France.

Abstract

Introduction: Lung cancer screening in individuals at risk has been recommended by various scientific institutions. One of the main concerns for CT screening is repeated radiation exposure, with the risk of inducing malignancies in healthy individuals. Therefore, lowering the radiation dose is one of the main objectives for radiologists. The aim of this study is to demonstrate that an ultra-low dose (ULD) chest CT protocol, using recently introduced hybrid iterative reconstruction (ASiR-V, GE medical Healthcare, Milwaukee, Wisconsin, USA), is as performant as a standard 'low dose' (LD) CT to detect non-calcified lung nodules ≥4 mm.

Methods and analysis: The total number of patients to include is 150. Those are referred for non-enhanced chest CT for detection or follow-up of lung nodule and will undergo an additional unenhanced ULD CT acquisition, the dose of which is on average 10 times lower than the conventional LD acquisition. Total dose of the entire exam (LD+ULD) is lower than the French diagnostic reference level for a chest CT (6.65 millisievert). ULD CT images will be reconstructed with 50% and 100% ASiR-V and LD CT with 50%. The three sets of images will be read in random order by two pair of radiologists, in a blind test, where patient identification and study outcomes are concealed. Detection rate (sensitivity) is the primary outcome. Secondary outcomes will include concordance of nodule characteristics; interobserver reproducibility; influence of subjects' characteristics, nodule location and nodule size; and concordance of emphysema, coronary calcifications evaluated by visual scoring and bronchial alterations between LD and ULD CT. In case of discordance, a third radiologist will arbitrate.

Ethics and dissemination: The study was approved by the relevant ethical committee. Each study participant will sign an informed consent form.

Trial registration number: NCT03305978; Pre-results.

Keywords: iterative reconstruction; low dose computed tomography; lung cancer screening; pulmonary nodule; ultra low dose computed tomography.

Publication types

Comparative Study
Research Support, Non-U.S. Gov't

MeSH terms

Adult
Algorithms*
Early Detection of Cancer / methods*
Female
Humans
Lung Neoplasms / diagnosis*
Male
Middle Aged
Multiple Pulmonary Nodules / diagnosis*
Radiation Dosage
Reproducibility of Results
Tomography, X-Ray Computed / methods*

Associated data

ClinicalTrials.gov/NCT03305978