Incidence of pulmonary embolism in younger versus older patients using CT

OBJECTIVE: The aim of this study is to compare the incidence of pulmonary embolism (PE) on computed tomography (CT) studies between younger and older patients to determine if there is an age-related bias for overutilization of CT pulmonary angiography (CTPA) in younger patients. MATERIAL AND METHODS: Six hundred thirty-one consecutive CTPA cases for suspected acute PE between 11/10/2003 and 3/19/2004 were retrospectively studied. Of these 631 cases, 59 patients were found to have clots in the pulmonary arteries (ranging from central to subsegmental PA). CTPA was performed using multidetector CT at 1.25-mm collimation, 120 kVp, 320 mA. Patients were categorized by gender and age: A, less than 20 (n=11); B, 20 to 29 (n=44); C, 30 to 39 (n=59); D, 40 to 49 (n=90); E, 50 to 59 (n=120); F, 60 to 69 (n=114); G, 70 to 79 (n=104); H, 80 to 89 (n=72); I, 90 or more (n=21). The incidences of PE were calculated in each gender and age group. To compare the incidence of PE between younger and older groups, they were divided into 2 groups at the ages of 40 (<39 and ≥40), 50 (<49 and ≥50), and 60 (<59 and ≥60). Statistical analysis was performed using the χ test. RESULTS: The incidences of PE were 11.9% in males (A, 0%; B, 17.6%; C, 10%; D, 8.3%; E, 13.3%; F, 6.9%; G, 17.5%; H, 23.5%; I, 0%), 7.7% in females (A, 0%; B, 7.4%; C, 5.1%; D, 12.5%; E, 4.2%; F, 14.5%; G, 7.8%; H, 5.5%; I, 0%), and 9.4% in total patients (A, 0%; B, 11.1%; C, 6.8%; D, 11.1%; E, 7.5%; F, 10.5%; G, 11.5%; H, 9.7%; I, 0%). No significant differences in the incidences of PE were observed when patients were divided at the age of 40 (male, female, total; P=1.0, 0.6252, 0.7220), at the age of 50 (male, female, total; P=0.6748, 0.6879, 1.0), or at the age of 60 (male, female, total; P=0.8458, 0.7046, 0.6820). CONCLUSION: No statistically significant difference in the incidence of PE was observed between younger and older patients. Our findings suggest that there is no age-related bias for overutilization of CT angiography (CTA) in younger patients.