• Children Suspected of Having Pulmonary Embolism: Multidetector CT Pulmonary Angiography—Thromboembolic Risk Factors and Implications for Appropriate Use

    Radiology: Volume 262: Number 1 -January 2012

    Edward Y. Lee, MD, MPH Sunny K. S. Tse, FRCR, MMed David Zurakowski, PhD Victor M. Johnson, MA Nam Ju Lee, MD Donald A. Tracy, MD Phillip M. Boiselle, MD

    Purpose: To evaluate thromboembolic risk factors for pulmonary embo­lism (PE) detected by using computed tomographic (CT) pul­monary angiography in children and to determine whether such information could be used for more appropriate use of CT pul­monary angiography in this patient population.

    Materials and Methods: The institutional review board approved this HIPAA-compliant ret­rospective study and waived the need for patient informed consent. Two hundred twenty-seven consecutive CT pulmonary angiography studies in 227 pediatric patients who underwent CT pulmonary angiography for clinically suspected PE at a single large pediatric referral hospital between July 2004 and March 2011 were evalu­ated. Age, sex, referral setting, and D-dimer result, as well as seven possible risk factors, were compared between patients with and those without PE. Multiple logistic regression modeling was used to identify the independent risk factors of PE. Receiver operating characteristic curve analysis was applied to determine the optimal cutoff number of risk factors for predicting a positive CT pulmonary angiography result for PE in children.

    Results: Thirty-six (16%) of 227 CT pulmonary angiography studies were positive for PE. Five risk factors, including immobilization (P < .001), hypercoagulable state (P = .003), excess estrogen state (P = .002), indwelling central venous line (P < .001), and prior PE and/or deep venous thrombosis (P < .001), were found to be significant independent risk factors for PE. With use of two or more risk factors as the clinical threshold, the sensitivity of a positive PE result was 89% (32 of 36 patients), and the spec­ificity was 94% (180 of 191 patients).

    Conclusion: It is unlikely for CT pulmonary angiography results to be positive for PE in children with no thromboembolic risk factors. The use of risk factor assessment as a first-line triage tool has the potential to guide more appropriate use of CT pulmonary angiography in children, with associated reductions in radiation exposure and costs.