Potential role for CT colonography in screening for aortic aneurysm
Familiar with the challenges facing implementation of a national
screening programme for colorectal cancer, we read with interest the
article and accompanying editorial promulgating abdominal aortic aneurysm
screening, based on the Gloucestershire experience (1). The role of
computed tomographic colonography (CT colonography or virtual colonoscopy)
is evolving and could potentially benefit such a programme.
CT colonography is a widely available technique examining both the
entire colorectum and extracolonic organs (2). The abdominal aorta is
always well visualised throughout its length allowing easy size assessment
and, unlike portable ultrasound, multi-planar reconstructions can be
instantly produced to provide recognisable and detailed anatomical
information for the surgeon.
In the UK, virtual colonoscopy is increasingly used as an alternative
to barium enema for symptomatic patients, particularly in frail or elderly
groups. In the USA however, there is a strong political lobby to include
virtual colonoscopy as one of the primary colorectal cancer screening
options reimbursed by the larger insurance agencies. If successful, large
numbers of eligible screenees will have their aorta examined, identifying
many of those with aneurysmal formation at an earlier age (50 to 70
years). Moreover, women in whom 28% of aneurysmal rupture deaths occur
would be examined (3) (they are currently excluded from the aneurysm
screening strategy adopted in Gloucestershire).
Although it could be sensibly argued that this approach is merely
whole-body screening by the back door, if properly targeted to the right
age and risk groups, then there is an opportunity to combine resources,
which might be popular with both the public and politicians alike.
1.Earnshaw JJ, Shaw E, Whyman MR, Poskitt KR, Heather BP. Screening
for abdominal aortic aneurysms in men. BMJ 2004;328:1122-4
2.Halligan S, Fenlon HM. Virtual colonoscopy. BMJ 1999; 319:1249-52
3.Law MR, morris J, Wald NJ. Screening for abdominal aortic
aneurysms. J Med Screen 1994; 1:110-6
All three authors provide remunerated advice to Medicsight, a CT software development company.
Competing interests: No competing interests