Risk of pulmonary embolism after a negative spiral CT angiogram in patients with pulmonary disease: 1-year clinical follow-up study.
OBJECTIVE
To evaluate the effect of pulmonary disease on diagnostic utility of spiral computed tomographic (CT) angiography in clinical practice.


METHODS
Three hundred thirty-four patients, including 215 patients with pulmonary disease (group 1) and 119 patients with no history of respiratory disorder (group 2), were referred for thin-collimation CT angiography of the pulmonary circulation as the first-line diagnostic test. Patients with negative angiograms who had not received anticoagulation therapy and who could be clinically followed up at 3 months, 6 months, and 1 year were considered in the final study groups (n = 185); 135 patients had lung disease (group 3), and 50 patients had no history of a respiratory disorder (group 4).


RESULTS
Between groups 3 and 4, no significant differences were found in the referral location, age, and risk factors. Confident evaluation of pulmonary arteries down to the subsegmental level was performed in 31 (23%) patients in group 3 and in 15 (30%) in group 4 (P =.5). Three episodes of acute pulmonary embolism (PE), all fatal, were diagnosed in group 3 patients; two cases occurred 14 days and one case occurred 6 months after the negative spiral CT scan. The negative predictive value of spiral CT angiography was 98% (175 of 178) in the study group in which follow-up was performed, with no significant difference between the values in groups 3 (98% [132 of 135]) and 4 (100% [50 of 50]).


CONCLUSIONS
Underlying respiratory disease does not affect the negative predictive value of thin-collimation CT angiography, which appears to be a reliable tool in the work-up in this subgroup of patients with acute PE.
Tillie-Leblond
Isabelle
I
Department of Pulmonology, University Center Hospital Calmette, Lille, France.
Mastora
Ioana
I
Radenne
Fabienne
F
Paillard
Sandrine
S
Tonnel
André-Bernard
AB
Remy
Jacques
J
Remy-Jardin
Martine
M
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000792:Angiography; D016009:Chi-Square Distribution; D005188:False Negative Reactions; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008171:Lung Diseases / Q000150:complications* / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging* / Q000209:etiology*; D012307:Risk Factors; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed / Q000379:methods*