Computed tomography of the chest with model-based iterative reconstruction using a radiation exposure similar to chest X-ray examination: preliminary observations.
OBJECTIVE
The purpose of this study was to assess the diagnostic image quality of ultra-low-dose chest computed tomography (ULD-CT) obtained with a radiation dose comparable to chest radiography and reconstructed with filtered back projection (FBP), adaptive statistical iterative reconstruction (ASIR) and model-based iterative reconstruction (MBIR) in comparison with standard dose diagnostic CT (SDD-CT) or low-dose diagnostic CT (LDD-CT) reconstructed with FBP alone.


METHODS
Unenhanced chest CT images of 42 patients acquired with ULD-CT were compared with images obtained with SDD-CT or LDD-CT in the same examination. Noise measurements and image quality, based on conspicuity of chest lesions on all CT data sets were assessed on a five-point scale.


RESULTS
The radiation dose of ULD-CT was 0.16 ± 0.006 mSv compared with 11.2 ± 2.7 mSv for SDD-CT (P < 0.0001) and 2.7 ± 0.9 mSv for LDD-CT. Image quality of ULD-CT increased significantly when using MBIR compared with FBP or ASIR (P < 0.001). ULD-CT reconstructed with MBIR enabled to detect as many non-calcified pulmonary nodules as seen on SDD-CT or LDD-CT. However, image quality of ULD-CT was clearly inferior for characterisation of ground glass opacities or emphysema.


CONCLUSIONS
Model-based iterative reconstruction allows detection of pulmonary nodules with ULD-CT with radiation exposure in the range of a posterior to anterior (PA) and lateral chest X-ray.
Department of Radiology, Geneva University Hospital, Rue Gabrielle-Perret-Gentil 4, 1211, Geneva 4, Switzerland.
Angeliki
A
Neroladaki
Diomidis
D
Botsikas
Sana
S
Boudabbous
Christoph D
CD
Becker
Xavier
X
Montet
D000328:Adult; D000368:Aged; D000465:Algorithms; D000704:Analysis of Variance; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008175:Lung Neoplasms / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D011446:Prospective Studies; D011656:Pulmonary Emphysema / Q000000981:diagnostic imaging*; D011786:Quality Control; D011829:Radiation Dosage; D011832:Radiation Injuries / Q000517:prevention & control; D013902:Radiography, Thoracic / Q000009:adverse effects / Q000379:methods*; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D003074:Solitary Pulmonary Nodule / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed / Q000009:adverse effects / Q000379:methods*; D055815:Young Adult