Detection of Incidental Nonosseous Thoracic Pathology on State-of-the-Art Ultralow-Dose Protocol Computed Tomography in Pediatric Patients With Pectus Excavatum

Abstract

The aim of the study was to compare a pediatric ultralow-dose pectus excavatum computed tomography (CT) protocol versus standarddose 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 agematched 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.

Advancements in preoperative imaging of pectus excavatum: a comprehensive review

“…Compared to a general low dose chest-CT of 10 mm slices from the sternal inlet to the costal margin, the mini-CT reduced the effective dose (mSv) by 63% (0.88 versus 0.32 mSv). The effective dose can be brought down even further to less than 0.15 mSv by implementing an ultralow-dose CT protocol ( 18 , 19 ). Gallo-Bernal et al [2022] compared an ultralow-dose CT protocol (70–80 kV; fixed tube current of 50 mAs; slice thickness 2.5 mm) to a standard-dose CT protocol (100–120 kV; variable tube current, smart mA; slice thickness 2.5 mm) by evaluating the effect on image quality as well as the capability to detect non-osseous thoracic pathology ( 18 ).…”

“…The effective dose can be brought down even further to less than 0.15 mSv by implementing an ultralow-dose CT protocol ( 18 , 19 ). Gallo-Bernal et al [2022] compared an ultralow-dose CT protocol (70–80 kV; fixed tube current of 50 mAs; slice thickness 2.5 mm) to a standard-dose CT protocol (100–120 kV; variable tube current, smart mA; slice thickness 2.5 mm) by evaluating the effect on image quality as well as the capability to detect non-osseous thoracic pathology ( 18 ). A scanning range from the thoracic inlet to the level of the adrenal glands was used and scans were reconstructed using adaptive statistical iterative reconstruction, which supports preservation of diagnostic image quality in low-dose CT acquisition.…”