Advances in determining abdominal aortic aneurysm size and growth

Table 1 Summary of studies comparing between various Dmax measurements

Ref.	Journal, yr	Variables	Main results	Highlights
Lederle et al[31]	J Vasc Surg, 1995	US, CTaxial	US smaller than CTaxial an average of 0.27 cm	Difference < 0.2 cm in 44% and > 0.5 cm in 33% of patients
Jaakkola et al[23]	Eur J Vasc Endovasc Surg, 1996	US, CTaxial	Mean AAA anteroposterior CTaxial-US difference was 2.6 ± 3.9 mm. Mean transverse difference was 0.8 ± 4.4	Interobsever differences < 5 mm in 84% of the US and 91% of the CTaxial recordings
Wanhainen et al[32]	Eur J Vasc Endovasc Surg, 2002	US, CTaxial	In AAAs the mean diameter did not differ significantly	95% of differences between US and CTaxial are expected to be < 8.0 mm in anteroposterior and < 10.6 mm in transverse measurements
Sprouse et al[33]	J Vasc Surg, 2003	US, CTaxial	CTaxial (5.69 ± 0.89 cm) significantly larger than US (4.74 ± 0.91 cm)	Strong correlation between CTmax and US (r = 0.705), but difference < 1.0 cm in only 51% of cases
Singh et al[34]	Eur J Vasc Endovasc Surg, 2004	US, CTaxial	Total: US smaller by -0.11 mm, aortas < 30 mm: US smaller by -0.64 mm, aortas 30-39 mm: CT smaller by 0.67 mm, aortas > 40 mm: CT smaller 1.09 mm	Differences > 5 mm are expected in 8% of patients. Variability increases with increasing diameter
Sprouse et al[35]	Eur J Vasc Endovasc Surg, 2004	US, CTaxial CTorth	Mean CTaxial (58.0 mm) significantly larger than USmax (53.9 mm) or CTorth (54.7 mm). Insignificant difference between US and Dorth	When aortic angulation was < 25°, Daxial (55.3 mm), US (54.3 mm), and Dorth (54.1 mm) were similar. When aortic angulation was > 25°, Daxial (60.1 mm) was significantly larger than US (53.8 mm) and Dorth (55.0 mm)
Manning et al[36]	J Vasc Surg, 2009	US, CTaxial, CTorth	US smaller than CTaxial by 9.6 mm and CTorth by 7.3 mm	Of all CT recordings, diameter perpendicular to the maximal ellipse on axial sections most closely approximates the findings of US and therefore this most closely approximates criteria used in the UKSAT
Foo et al[37]	Eur J Vasc Endovasc Surg, 2011	US, CTorth	US underestimated AAA size compared to CTorth by a mean difference of 0.21 (± 0.39) cm	Limits of agreement were -0.55 to 0.96 cm, exceeding clinical acceptability. 70% of patients with US < 5.5 cm presented CTorth > 5.5 cm
Kontopodis et al[38]	Eur J Radiol, 2013	CTaxial, CTorth	CTaxial greater than CT orth by 2 mm (range: 0-12.3 mm)	20% of the CTs presented Daxial above and Dorth below 5.5 cm which is threshold for repair. Growth rates should be determined with either axial or orthogonal technique not interchanging between methods

AAA: Abdominal aortic aneurysm; CT: Computed tomography; CTorth: Orthogonal maximum diameter measured from CT images; CTaxial: Axial maximum diameter measured from CT images; US: Ultrasonography.