Chest High-Resolution Computed Tomography for chronic suppurative lung disease in late childhood and early adolescence: Radiation dose and image quality evaluation using iDose4 Iterative Reconstruction Algorithm

Magdalini Smarda, Efstathios Efstathopoulos, Agapi Ploussi, Argyro Mazioti, Sophia Kordolaimi, Nikolaos Kelekis, Efthymia Alexopoulou


Purpose: The large number of computed tomography (CT) examinations taking place in everyday clinical practice has increased the risk for radiation-induced carcinogenesis, especially in children with longer life expectancy than adults. The recently developed Iterative Reconstruction (IR) algorithms reduce image noise and therefore radiation exposure. This study compares the iDose4 IR Algorithm with Filtered-Back Projection (FBP) in terms of radiation exposure and image quality (IQ) in 31 chest high resolution CT (HRCT) examinations performed in school-aged children with chronic suppurative lung disease (7-13 years old, weighing >30 kgs).

Material and Methods: Thirteen patients were scanned using the FBP protocol (FBP group) and 18 patients using the iDose4 protocol (iDose group) and reduced tube current-time product (mAs). Both groups were scanned on a 64-detector row CT scanner. The iDose group images were reconstructed with iDose levels 2, 4 and 6. Radiation exposure was estimated, while subjective and objective IQ was evaluated. Unpaired t-test was used for data statistical analysis.

Results: The iDose4 application allowed a significant dose reduction (up to 64%). Subjective image noise was comparable between FBP and iDose4 images, whereas objective image noise was comparable between FBP and iDose level 2 images. Oversmoothing artefacts already described in literature were only noticed in a few cases with iDose level 6, but without significantly affecting the diagnostic acceptability.

Conclusions: The use of the iDose4 IR algorithm in chest HRCT of preadolescent and early adolescent-aged children leads to significant dose reduction, without significantly affecting IQ. Further evaluation with a larger patient sample and lower mAs settings is needed in order to investigate further reduction of exposure parameters in chest HRCT of children weighing more than 30 kgs.


image quality; iterative reconstruction; iDose; radiation dose reduction; chronic suppurative lung disease

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