Evaluation of pulmonary embolism in pediatric patients with nephrotic syndrome with dual energy CT pulmonary angiography.

RATIONALE AND OBJECTIVES: The purposes of this study were to evaluate the prevalence of pulmonary embolism (PE) and renal vein thrombosis in pediatric patients with nephrotic syndrome using combined dual-energy (DE) computed tomographic (CT) pulmonary angiography (CTPA) and renal CT venography and to evaluate whether DE CTPA can improve the detection of PE in these children.

MATERIALS AND METHODS: Thirty-two children (aged ≤ 18 years) were included in this study. All children underwent contrast-enhanced DE CTPA and renal CT venography; seven also underwent follow-up DE CTPA and renal CT venography. The presence of PE was determined by (1) CTPA derived from the average weighted 120-kVp images and (2) DE CTPA using dedicated DE software (syngo DE Lung PBV and syngo DE Lung Vessels), which can extract the iodine contents in lung parenchyma and pulmonary arteries. The prevalence and anatomic distribution of PE on CTPA from the average weighted 120-kVp images and DE CTPA and of renal vein thrombosis on CT venography were recorded by two radiologists in consensus; χ(2) tests were used to compare the difference in the detection rate of PE between DE CTPA and conventional CTPA.

RESULTS: Of 32 children, nine (28.1%) had PE on the basis of the comprehensive DE CT pulmonary angiographic evaluation (CTPA from average weighted 120-kVp images and perfusion images and vascular images generated using the DE CT software). PE was localized in the lobar pulmonary artery in five patients (55.6%), the segmental pulmonary artery in six (66.7%), and the subsegmental pulmonary artery in five (55.6%). PE was distributed in the right upper lobe in two patients (22.2%), the right middle lobe in two (22.2%), the right lower lobe in five (55.6%), and the left lower lobe in six (66.7%). Compared to the CTPA derived from average weighted 120-kVp data, comprehensive DE CTPA showed solitary subsegmental PE in one additional patient (nine vs eight patients), one additional segmental (11 vs 10 segments), and four additional subsegmental pulmonary emboli (two vs six subsegmental pulmonary emboli) (P > .05 for all). Eight children (25%) had renal vein thrombosis extending to the inferior vena cava (n = 5).

CONCLUSIONS: The prevalence of PE was 28.1% and that of renal vein thrombosis 25.0% in the pediatric population with nephrotic syndrome on the basis of our small cohort. DE CTPA has the potential to improve the detection of PE in the pediatric population.