Objective

The aim of the study was to compare a pediatric ultralow-dose pectus excavatum computed tomography (CT) protocol versus standard-dose pediatric thoracic CT in terms of radiation dose, subjective and objective image quality, and its ability to detect incidental nonosseous thoracic pathology compared with imaging and clinical reference.

Methods

A single institution radiology database identified a total of 104 ultralow-dose pediatric thoracic CT cases with an equal number of age-matched standard-dose chest CT cases also selected for retrospective analysis. Objective image quality (contrast-to-noise and signal-to-noise ratios) and radiation dose were assessed. Qualitative Likert scorings of the bone, lung, and soft tissues were performed by 2 expert radiologists. Electronic health records of the ultralow-dose cohort were reviewed for at least 1 year to evaluate for potentially missed thoracic pathology and symptoms. Variables were compared using parametric and nonparametric tests in R software 4.0. 5.

Results

The ultralow-dose protocol group had statistically significant reductions (P< 0.001) in the volume CT dose index (0.31±0.19 vs 2.20±1.64 mGy), effective radiation dose (0.14±0.08 vs 1.07±0.86 mSv), and size-specific dose estimates (0.50±0.30 vs 3.43±2.56 mGy) compared with the standard protocol, yielding an 86.51% and 85.32% reduction, respectively. The signal-to-noise ratio (20.49±6.19 vs 36.48±10.20), contrast-to-noise (21.65±6.57 vs 38.47±10.59), and subjective measures of image quality (lung parenchyma [3.07±0.92 vs 4.42±0.47], bony structures [3.30±0.86 vs 4.52±0.51], and surrounding soft tissues [2.57±0.63 vs 3.89±0.65]) were also significantly lower in the ultralow-dose protocol (P< 0.001). No differences were seen in the number and size of pulmonary nodules between groups. Clinical and imaging follow of all 104 patients undergoing ultralow-dose CT demonstrated no evidence of missed thoracic pathology causing symptoms.

Conclusions

Ultralow-dose thoracic CT is an acceptable modality for imaging pediatric patients with pectus excavatum and other conditions primarily causing osseous pathology, with effective radiation dose comparable to plain radiographs and a moderate increase in image noise that did not significantly reduce its ability to detect incidental nonosseous thoracic pathology.