Tailored CT angiography in follow-up after endovascular aneurysm repair (EVAR): combined dose reduction techniques

Abstract

Background

Endovascular aneurysm repair (EVAR) requires lifelong surveillance by computed tomography angiography (CTA). This is attended by a substantial accumulation of radiation exposure. Iterative reconstruction (IR) has been introduced to approach dose reduction.

Purpose

To evaluate adaptive statistical iterative reconstruction (ASIR) at different levels of tube voltage concerning image quality and dose reduction potential in follow-up post EVAR.

Material and Methods

One hundred CTAs in 67 patients with EVAR were examined using five protocols: protocol A (n = 40) as biphasic standard using filtered back projection (FBP) at 120 kV; protocols B (n = 40), C (n = 10), and D1 (n = 5) biphasic using ASIR at 120, 100, and 80 kV, respectively; and protocol D2 (n = 5) with a monophasic splitbolus ASIR protocol at 80 kV. Image quality was assessed quantitatively and qualitatively. Applied doses were determined.

Results

Applied doses in ASIR protocols were significantly lower than FBP standard (up to 75%). Compared to protocol A, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) (e.g. arterial CNR intra-/extra-stent lumen: A = 35.4 ± 13.5, B = 34.2 ± 10.0, C = 29.6 ± 6.8, D1 = 32.1 ± 6.3, D2 = 40.8 ± 23.1) in protocol B were equal and in protocols C and D equal to partially inferior, however not decisive for diagnostic quality. Subjective image quality ratings in all protocols were good to excellent without impairments of diagnostic confidence (A–D2: 5), with high inter-rater agreement (60–100%).

Conclusion

ASIR contributes to significant dose reduction without decisive impairments of image quality and diagnostic confidence. We recommend an adapted follow-up introducing ASIR and combined low-kV in the long-term surveillance after EVAR.

Keywords

Computed tomography angiography (CTA)stents interventional aorta aneurysms

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References

Maddu

Telleria

Shuaib

et al.

Nontraumatic acute aortic emergencies: Part 2, Pre- and postsurgical complications related to aortic aneurysm in the emergency clinical setting. Am J Roentgenol 2014; 202: 666–674.

Sampson

Norman

Fowkes

et al.

Estimation of global and regional incidence and prevalence of abdominal aortic aneurysms 1990 to 2010. Glob Heart 2014; 9: 159–170.

Prinssen

Wixon

Buskens

et al.

Surveillance after endovascular aneurysm repair: diagnostics, complications, and associated costs. Ann Vasc Surg 2004; 18: 421–427.

Mita

Arita

Matsunaga

et al.

Complications of endovascular repair for thoracic and abdominal aortic aneurysm: an imaging spectrum. Radiographics 2000; 20: 1263–1278.

Liaw

Clark

Gibbs

et al.

Update: Complications and management of infrarenal EVAR. Eur J Radiol 2009; 71: 541–551.

Bauchaortenaneurysma und Beckenarterienaneurysma (S2). Leitlinien zu Diagnostik und Therapie in der Gefäßchirurgie , Berlin, Heidelberg: Springer, 2010.

Moll

Powell

Fraedrich

et al.

Management of abdominal aortic aneurysms clinical practice guidelines of the European society for vascular surgery. Eur J Vasc Endovasc Surg 2011; 41(Suppl 1): S1–S58.

Hansen

Kaza

Maturen

et al.

Evaluation of low-dose CT angiography with model-based iterative reconstruction after endovascular aneurysm repair of a thoracic or abdominal aortic aneurysm. Am J Roentgenol 2014; 202: 648–655.

Nyheim

Staxrud

Jorgensen

et al.

Radiation exposure in patients treated with endovascular aneurysm repair: what is the risk of cancer, and can we justify treating younger patients?. Acta Radiol 2017; 58: 323–330.

10.

Gervaise

Osemont

Lecocq

et al.

CT image quality improvement using adaptive iterative dose reduction with wide-volume acquisition on 320-detector CT. Eur Radiol 2012; 22: 295–301.

11.

Lehti

Nyman

Soderberg

et al.

80-kVp CT angiography for endovascular aneurysm repair follow-up with halved contrast medium dose and preserved diagnostic quality. Acta Radiol 2016; 57: 279–286.

12.

Willemink

de Jong

Leiner

et al.

Iterative reconstruction techniques for computed tomography Part 1: technical principles. Eur Radiol 2013; 23: 1623–1631.

13.

Willemink

Leiner

de Jong

et al.

Iterative reconstruction techniques for computed tomography part 2: initial results in dose reduction and image quality. Eur Radiol 2013; 23: 1632–1642.

14.

Kahn

Grupp

Rotzinger

et al.

CT for evaluation of potential renal donors - how does iterative reconstruction influence image quality and dose?. Eur J Radiol 2014; 83: 1332–1336.

15.

Hung

Sun

et al.

How far can the radiation dose be lowered in head CT with iterative reconstruction? Analysis of imaging quality and diagnostic accuracy. Eur Radiol 2013; 23: 2612–2621.

16.

Beister

Kolditz

Kalender

. Iterative reconstruction methods in X-ray CT. Phys Med 2012; 28: 94–108.

17.

Schabel

Fenchel

Schmidt

et al.

Clinical evaluation and potential radiation dose reduction of the novel sinogram-affirmed iterative reconstruction technique (SAFIRE) in abdominal computed tomography angiography. Acad Radiol 2013; 20: 165–172.

18.

Deak

Smal

Kalender

. Multisection CT protocols: sex- and age-specific conversion factors used to determine effective dose from dose-length product. Radiology 2010; 257: 158–166.

19.

Landis

Koch

. The measurement of observer agreement for categorical data. Biometrics 1977; 33: 159–174.

20.

Boning

Schafer

Grupp

et al.

Comparison of applied dose and image quality in staging CT of neuroendocrine tumor patients using standard filtered back projection and adaptive statistical iterative reconstruction. Eur J Radiol 2015; 84: 1601–1607.

21.

Boning

Kahn

Kaul

et al.

CT follow-up in patients with neuroendocrine tumors (NETs): combined radiation and contrast dose reduction. Acta Radiol 2017. doi: 10.1177/0284185117726101.

22.

Shuman

Green

Busey

et al.

Model-based iterative reconstruction versus adaptive statistical iterative reconstruction and filtered back projection in liver 64-MDCT: focal lesion detection, lesion conspicuity, and image noise. Am J Roentgenol 2013; 200: 1071–1076.

23.

de Bucourt

Muhler

Kroncke

et al.

Endoleak after endovascular aneurysm repair: evaluation of a single-acquisition CTA protocol using a prebolus. J Endovasc Ther 2011; 18: 771–778.

24.

Kalva

Sahani

Hahn

et al.

Using the K-edge to improve contrast conspicuity and to lower radiation dose with a 16-MDCT: a phantom and human study. J Comput Assist Tomogr 2006; 30: 391–397.

25.

Cicchetti

Feinstein

. High agreement but low kappa: II. Resolving the paradoxes. J Clin Epidemiol 1990; 43: 551–558.

26.

Feinstein

Cicchetti

. High agreement but low kappa: I. The problems of two paradoxes. J Clin Epidemiol 1990; 43: 543–549.

27.

Andreucci

Faga

Pisani

et al.

Acute kidney injury by radiographic contrast media: pathogenesis and prevention. Biomed Res Int 2014; 2014: 362725.