title: Quantification of aortic distensibility in abdominal aortic aneurysm using ECG-gated multi-detector computed tomography.
abstract: OBJECTIVE
  To detect distensibility changes that might be an indicator for an increased risk of rupture, cross-sectional area changes of abdominal aortic aneurysms (AAA) have been determined using ECG-gated CT.
  
  
  METHODS
  Distensibility measurements of the aorta were performed in 67 patients with AAA. Time-resolved images were acquired with a four detector-row CT system using a modified CT-angiography protocol. Pulsatility-related cross-sectional area changes were calculated above and at AAA level by semiautomatic segmentation; distensibility values were obtained using additional systemic blood pressure measurements. Values were compared for small Ø<5 cm (n=44) and large Ø>5 cm (n=23) aneurysms.
  
  
  RESULTS
  The aorta could be segmented successfully in all patients. Upstream AAA distensibility D was significantly higher than at AAA level for both groups: means above AAA (at AAA) D(above)=(1.3+/-0.8) x 10(-5) Pa(-1) (D(AAA )=(0.6+/-0.5) x 10(-5) Pa(-1)) t-test p(D)<0.0001. Differences of the distensibility between smaller and larger aneurysms were not found to be significant.
  
  
  CONCLUSIONS
  Distensibility can be measured non-invasively with ECG-gated CT. The reduction of distensibility within aneurysms compared to normal proximal aorta is subtle; the lack of difference between both small and large aneurysms suggests that this reduction occurs early in the aneurysm's development. Hence, reduced distensibility might be a predictive parameter in patients with high risk of aortic disease.
authors.affiliation: Department of Radiology, Medical Physics in Radiology, Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany. m.ganten@dkfz-heidelberg.de
authors.forename: Maria-Katharina
authors.initials: MK
authors.lastname: Ganten
authors.forename: Ute
authors.initials: U
authors.lastname: Krautter
authors.forename: Hendrik
authors.initials: H
authors.lastname: von Tengg-Kobligk
authors.forename: Dittmar
authors.initials: D
authors.lastname: Böckler
authors.forename: Hardy
authors.initials: H
authors.lastname: Schumacher
authors.forename: Wolfram
authors.initials: W
authors.lastname: Stiller
authors.forename: Stefan
authors.initials: S
authors.lastname: Delorme
authors.forename: Hans-Ulrich
authors.initials: HU
authors.lastname: Kauczor
authors.forename: Günter W
authors.initials: GW
authors.lastname: Kauffmann
authors.forename: Michael
authors.initials: M
authors.lastname: Bock
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D000792:Angiography; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging / Q000503:physiopathology; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D014057:Tomography, X-Ray Computed / Q000379:methods*