Abstract
Background: Pulmonary embolism (PE) associated with Mycoplasma pneumoniae pneumonia (MPP) in children has already attracted more attention. We aimed to evaluate the application of dual-energy spectral CT in diagnosing PE in children with MPP.Methods: Eight-three children with MPP and highly suspected PE, underwent CT pulmonary angiography (CTPA) with spectral imaging mode. Noise, clot-to-artery contrast-to-noise ratio, image quality and diagnosis confidence were calculated and assessed on nine monochromatic image sets (40 to 80keV). CTPA images were observed for the presence, localization, and embolic degrees of PE. Emboli were divided between intra and extra-consolidation. For extra-consolidation clots, iodine concentration (IC) of perfusion defects and normal lung, perfusion defects of 4 children before and after the treatment were measured and compared. For intra-consolidation clots, IC of consolidation areas with clots and consolidation areas without clot were measured and compared.Results: The optimal energy level for detecting PE in children was 55 keV. 116 clots (29 extra consolidations) were found in 25 children, IC of defect regions associated with PE was 0.69±0.28mg/mL (extra-consolidations) and 0.90±0.23mg/mL (intra-consolidations), both significantly lower than the 2.76±0.45mg/mL in normal lungs and 10.25±1.76mg/mL in consolidations without clots (P<0.001). Significant difference was found in the presence or absence of perfusion defects between occlusive clots and nonocclusive clots(P<0.001). IC of the perfusion defects significantly increased after treatment (P<0.001).Conclusions: In spectral CTPA 55 keV images optimize PE detection for children. and MD images quantify pulmonary blood flow of PE, and may help to detect small clots and quantify embolic degrees.
Dual energy spectral CT imaging of pulmonary embolism with Mycoplasma pneumoniae pneumonia in children
