Computer-assisted detection of pulmonary embolism: evaluation of pulmonary CT angiograms performed in an on-call setting.
OBJECTIVE
The purpose of the study was to assess the stand-alone performance of computer-assisted detection (CAD) for evaluation of pulmonary CT angiograms (CTPA) performed in an on-call setting.


METHODS
In this institutional review board-approved study, we retrospectively included 292 consecutive CTPA performed during night shifts and weekends over a period of 16 months. Original reports were compared with a dedicated CAD system for pulmonary emboli (PE). A reference standard for the presence of PE was established using independent evaluation by two readers and consultation of a third experienced radiologist in discordant cases.


RESULTS
Original reports had described 225 negative studies and 67 positive studies for PE. CAD found PE in seven patients originally reported as negative but identified by independent evaluation: emboli were located in segmental (n = 2) and subsegmental arteries (n = 5). The negative predictive value (NPV) of the CAD algorithm was 92% (44/48). On average there were 4.7 false positives (FP) per examination (median 2, range 0-42). In 72% of studies <or=5 FP were found, 13% of studies had >or=10 FP.


CONCLUSIONS
CAD identified small emboli originally missed under clinical conditions and found 93% of the isolated subsegmental emboli. On average there were 4.7 FP per examination.
Wittenberg
Rianne
R
Department of Radiology, Academic Medical Centre, Amsterdam, The Netherlands. r.wittenberg@amc.uva.nl
Peters
Joost F
JF
Sonnemans
Jeroen J
JJ
Prokop
Mathias
M
Schaefer-Prokop
Cornelia M
CM
D000293:Adolescent; D000328:Adult; D039602:After-Hours Care / Q000706:statistics & numerical data*; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D000792:Angiography / Q000706:statistics & numerical data*; D001185:Artificial Intelligence; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D010363:Pattern Recognition, Automated / Q000379:methods*; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D011856:Radiographic Image Enhancement / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data*; D055815:Young Adult