Accuracy of serial screening for abdominal aortic aneurysms by ultrasound.
OBJECTIVE
To assess the accuracy of screening for abdominal aortic aneurysms (AAAs) by ultrasound (US).


METHODS
An aneurysm screening programme in Huntingdon.


METHODS
False negative tests were identified by tracing all patients with a ruptured aneurysm who were screened and then finding the number classified as normal on US. False positive tests were identified by calculating the number of aneurysmal aortas on US that were classified as normal on CT. Measurement variability of the infrarenal aortic diameter between US and CT was estimated.


RESULTS
14 out of 93 patients with a ruptured AAA since 1991 had been screened. No ruptured aneurysm had been classified as normal on US. All 64 patients with an AAA larger than 4.5 cm on US had their aneurysm confirmed on CT. The mean difference between CT and US measurements was 4 mm. The limit of variability between CT and US was 12 mm.


CONCLUSIONS
No false negative scans were found using a cut off point of 3 cm as abnormal. No false positives were found if subjects with an AAA exceeding 4.5 cm were referred for further procedures. A serial US screening policy has excellent screening performance, justifying its use as a screening tool.
Wilmink
A B M
AB
Birmingham Heartlands Hospital, Birmingham UK Medway Hospital, Gillingham, UK. abmw100@doctors.org.uk
Forshaw
M
M
Quick
C R G
CR
Hubbard
C S
CS
Day
N E
NE
D017542:Aneurysm, Ruptured / Q000517:prevention & control; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods*; D011237:Predictive Value of Tests; D015397:Program Evaluation; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography