Clinical studyImage Quality of Virtual Noncontrast Images Derived from Dual-energy CT Angiography after Endovascular Aneurysm Repair
Section snippets
Patient Population
Between July 2007 and September 2008, 58 patients (48 men, 10 women; average age, 69.9 years ± 9.4; range, 47–75 y) underwent 70 dual-energy CT examinations after endovascular repair of aortic aneurysms. Time interval between EVAR and CT examination was 327 days ± 383. The study was approved by our institutional review board and all patients provided written informed consent prior to their participation in the trial.
For each patient, the body mass index was calculated (in kg/m2) by dividing
Patients
All patients underwent dual-energy CT without complications. Fifty of the patients had an abdominal, y-shaped stent-graft and eight had thoracic stent-grafts.
In session 1, with virtual noncontrast and dual-energy venous-phase imaging, 24 endoleaks were observed in 22 patients among the 70 CT examinations. Eight endoleaks were classified as type I (type Ia, n = 5; type Ib, n = 3). Eleven endoleaks were classified as type II (Fig 2) and five as type III. No cases of stent displacement or rupture
Discussion
Our quantitative and qualitative analysis of virtual noncontrast and true noncontrast images underlines that dual-energy CT–based virtual noncontrast images are a reasonable approximation of true unenhanced single-energy CT images, both in image quality parameters and in detection sensitivity for endoleaks. Although virtual noncontrast image quality is somewhat inferior, overall acceptance for diagnostic reading in patients who had undergone EVAR was good. Three nondiagnostic ratings were
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None of the authors have identified a conflict of interest.
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W.H.S. and A.G. contributed equally to this work.