Prospective Study of Low-Radiation and Low-Iodine Dose Aortic CT Angiography in Obese and Non-Obese Patients: Image Quality and Impact of Patient Characteristics.

Claudius Melzig,Fabian Rengier,Hans-Ulrich Kauczor,Andrea Steuwe,Sibylle Stoll,Sasan Partovi,Dittmar Böckler,Matthias A Fink

doi:10.3390/diagnostics12030675

Abstract

The purpose of this study was to prospectively analyse image quality and radiation dose of body mass index (BMI)-adapted low-radiation and low-iodine dose CTA of the thoracoabdominal aorta in obese and non-obese patients. This prospective, single-centre study included patients scheduled for aortic CTA between November 2017 and August 2020 without symptoms of high-grade heart failure. A BMI-adapted protocol was used: Group A/Group B, BMI < 30/≥ 30 kg/m2, tube potential 80/100 kVp, total iodine dose 14.5/17.4 g. Intraindividual comparison with the institutional clinical routine aortic CTA protocol was performed. The final study cohort comprised 161 patients (mean 71.1 ± 9.4 years, 32 women), thereof 126 patients in Group A (mean BMI 25.4 ± 2.8 kg/m2) and 35 patients in Group B (34.0 ± 3.4 kg/m2). Mean attenuation over five aortoiliac measurement positions for Group A/B was 354.9 ± 78.2/262.1 ± 73.0 HU. Mean effective dose for Group A/B was 3.05 ± 0.46/6.02 ± 1.14 mSv. Intraindividual comparison in 50 patients demonstrated effective dose savings for Group A/B of 34.4 ± 14.5/25.4 ± 14.1% (both p < 0.001), and iodine dose savings for Group A/B of 54/44.8%. Regression analysis showed that female sex and increasing age were independently associated with higher vascular attenuation. In conclusion, BMI-adapted, low-radiation and low-iodine dose CTA of the thoracoabdominal aorta delivers diagnostic image quality in non-obese and obese patients without symptoms of high-grade heart failure, with superior image quality in females and the elderly.

Highlights

Computed tomography angiography (CTA) is the imaging modality of choice for diagnosis, follow-up, and preoperative planning of most aortic diseases [1–3]
Regression analysis showed that female sex and increasing age were independently associated with higher vascular attenuation
Regression analysis revealed that female sex and increasing age were independently associated with higher vascular attenuation after adjustment for body mass index (BMI), tube potential, and tube current

Summary

Introduction

Computed tomography angiography (CTA) is the imaging modality of choice for diagnosis, follow-up, and preoperative planning of most aortic diseases [1–3]. Studies achieved a mean ED of 4.4–9.6 mSv and mean total iodine doses of 10.5–41 g for CTA of the thoracoabdominal aorta and demonstrated diagnostic image quality of low tube potential protocols for non-obese patients [8,9,11,13–15]. Previous studies suggested insufficient image quality of low tube potential protocols for obese patients, excluded patients with a BMI ≥ 30 kg/m2, did not report the body weight and body mass index (BMI), or optimised only either radiation or iodine dose [8,9,11,13–15]. Our hypothesis was that radiation and iodine dose for aortic CTA could be reduced for both non-obese and obese patients by means of an optimised, BMI-adapted CTA protocol. The purpose of this study was to prospectively analyse image quality and radiation dose of an optimised, BMI-adapted low-radiation and low-iodine dose CTA protocol for the thoracoabdominal aorta in non-obese and obese patients, and to investigate the impact of patient characteristics on the image quality of the low-dose CTA protocol

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