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The widespread use of EVAR has become apparent in the past decades. The favorable perioperative mortality rate (1.1% vs. 4.6% in Hungary and 0.6% vs. 3.8% in the United States) and the totally percutaneous nature of the procedure were the main driving factors of its success. However, major trials focusing on the long-term outcome of EVAR reported higher re-intervention rate with EVAR few years after the index procedure as compared to open repair. It is evident that as the number of EVARs grew over the years, a subsequent rise in the number of graft-related complications occurred. Thus, it was pertinent to adequately address the sequela of EVAR by utilizing advanced imaging techniques, such as dynamic, time-resolved CTA imaging.
In our study we describe the protocol developed for endoleak detection with d-CTA and the use of objective parameters such as time to peak value in endoleak characterization. We found that d-CTA had a 100% accuracy to characterize endoleaks as compared to the standard of care, t-CTA, which showed a 73.7% accuracy, when DSA was the baseline reference.
Regarding the comparison of radiation exposure, the optimized d-CTA scans had a mean (±SD) dose-length product of 1445 (±550) and t-CTA had 1612 (±530) mGy*cm (p=0.255).
During a quantitative analysis of 23 patients, TTP values (mean ±SD) between ROIaorta and ROIendoleak were 1.8 ± 1.8 seconds for type I (n=4), 9.6 ± 3.5 seconds for type II (n=16), and 5.6 ± 1.3 seconds for type III endoleak (n=3), respectively. ∆TTP range was significantly narrower for type I endoleak as compared to type II endoleak.
In our studies d-CTA identified more target vessels contributing to type II endoleaks compared to other modalities (d-CTA, t-CTA, and DSA were 23, 17, and 16, respectively (p=0.009) and 33 vs. 21 vessels, p=0.010 (d-CTA vs DSA).
Our findings indicate that d-CTA was superior in endoleak characterization compared to t-CTA at an equivalent level of radiation. In type II endoleak cases d-CTA identified more vessels contributing to the endoleak as compared to t-CTA or DSA. Additionally, utilizing quantitative parameters such as ∆TTP can further aid differential diagnosis of endoleaks.
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