Potential value of aneurysm sac volume measurements in addition to diameter measurements after endovascular aneurysm repair.
OBJECTIVE
To investigate the value of aneurysm sac volume measurement in addition to diameter measurements based on computed tomographic angiography (CTA) after endovascular aneurysm repair (EVAR).


METHODS
Interrogation of a vascular database identified 56 patients (51 men; median age 77 years, range 59-92), 28 with an endoleak and 28 without, who had digital CTA data available at baseline (first postoperative scan) and at 1 and 2 years after EVAR. Total aneurysm volume, transverse maximum diameter (TMD), and orthogonal maximum diameter (OMD; perpendicular to the aortic center lumen line) were compared for all patients and between those with and without endoleak. Differences of 5% for volume and 5 mm for diameters were considered a significant change. Kappa statistics were used to compare measurements.


RESULTS
Volumetry detected aneurysm growth in 32 (24%) of 131 scans, which was reflected by TMD in 12 (38%) and by OMD in 14 (44%). Eighteen scans with increasing aneurysm volume were measured in patients with endoleaks, which was documented by TMD in 6 (33%) and by OMD in 8 (44%). Fourteen volume increases were measured in patients without endoleak; both TMD and OMD documented only 43%. Volumetry detected aneurysm shrinkage in 71 (54%) of 131 scans [detected by TMD in 38 (54%) and by OMD in 37 (52%)]. Thirty-two volume decreases were measured in patients with an endoleak, noted by TMD in 18 (56%) and OMD in 14 (44%). Thirty-nine scans showed decreasing volumes in patients without endoleaks; the TMD corresponded in 20 (51%) and the OMD in 23 (59%). The kappa agreements for volume increase were 0.42 (TMD) and 0.35 (OMD) and for volume decrease 0.48 (TMD) and 0.47 (OMD); different thresholds of change produced similar moderate-range kappa values (0.3-0.6).


CONCLUSIONS
Volumetry detects sac size changes that are not reflected in diameter measurements. Vice versa, diameters can increase without a total volume increase, which might indicate a variety of morphological aneurysm changes. The agreement between volume and diameter measurements using different cutoff values is equally moderate. Volume measurements should be performed in addition to diameter measurements.
van Keulen
Jasper W
JW
Departments of Vascular Surgery, University Medical Center Utrecht, The Netherlands.
van Prehn
Joffrey
J
Prokop
Mathias
M
Moll
Frans L
FL
van Herwaarden
Joost A
JA
D000368:Aged; D000369:Aged, 80 and over; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging* / Q000601:surgery*; D001027:Aortography / Q000379:methods*; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation / Q000295:instrumentation; D019992:Databases as Topic; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011475:Prosthesis Failure; D015607:Stents; D013997:Time Factors; D036542:Tomography, Spiral Computed; D016896:Treatment Outcome