A BMI-adjusted ultra-low-dose CT angiography protocol for the peripheral arteries-Image quality, diagnostic accuracy and radiation exposure

Markus M Schreiner; Hannes Platzgummer; Sylvia Unterhumer; Michael Weber; Gabriel Mistelbauer; Christian Loewe; Ruediger E Schernthaner

doi:10.1016/j.ejrad.2017.06.002

A BMI-adjusted ultra-low-dose CT angiography protocol for the peripheral arteries-Image quality, diagnostic accuracy and radiation exposure

Eur J Radiol. 2017 Aug:93:149-156. doi: 10.1016/j.ejrad.2017.06.002. Epub 2017 Jun 3.

Authors

Markus M Schreiner¹, Hannes Platzgummer², Sylvia Unterhumer³, Michael Weber⁴, Gabriel Mistelbauer⁵, Christian Loewe⁶, Ruediger E Schernthaner⁷

Affiliations

¹ Section of Cardiovascular and Interventional Radiology, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria. Electronic address: markus.schreiner@meduniwien.ac.at.
² Section of Cardiovascular and Interventional Radiology, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria. Electronic address: hannes.platzgummer@meduniwien.ac.at.
³ Section of Cardiovascular and Interventional Radiology, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria. Electronic address: sylvia.unterhumer@meduniwien.ac.at.
⁴ Section of Cardiovascular and Interventional Radiology, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria. Electronic address: michael.weber@meduniwien.ac.at.
⁵ Institute of Computer Graphics and Algorithms, Technical University of Vienna, Favoritenstraße 9-11, 1040 Vienna, Austria. Electronic address: gabriel.mistelbauer@cg.tuwien.ac.at.
⁶ Section of Cardiovascular and Interventional Radiology, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria. Electronic address: christian.loewe@meduniwien.ac.at.
⁷ Section of Cardiovascular and Interventional Radiology, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria. Electronic address: ruediger@schernthaner.eu.

PMID: 28668409
DOI: 10.1016/j.ejrad.2017.06.002

Abstract

Objectives: To investigate radiation exposure, objective image quality, and the diagnostic accuracy of a BMI-adjusted ultra-low-dose CT angiography (CTA) protocol for the assessment of peripheral arterial disease (PAD), with digital subtraction angiography (DSA) as the standard of reference.

Methods: In this prospective, IRB-approved study, 40 PAD patients (30 male, mean age 72 years) underwent CTA on a dual-source CT scanner at 80kV tube voltage. The reference amplitude for tube current modulation was personalized based on the body mass index (BMI) with 120 mAs for [BMI≤25] or 150 mAs for [25<BMI≤30]. Iterative image reconstruction was applied. The presence of significant stenoses (>70%) was assessed by two readers independently and compared to subsequent DSA. Radiation exposure was assessed with the computed tomography dose index (CTDIvol) and the dosis-length product (DLP). Objective image quality was assessed via contrast- and signal-to-noise ratio (CNR and SNR) measurements. Radiation exposure and image quality were compared between the BMI groups and between the BMI-adjusted ultra-low-dose protocol and the low-dose institutional standard protocol (ISP).

Results: The BMI-adjusted ultra-low-dose protocol reached high diagnostic accuracy values of 94% for Reader 1 and 93% for Reader 2. Moreover, in comparison to the ISP, it showed significantly (p<0.001) lower CTDIvol (1.97±0.55mGy vs. 4.18±0.62 mGy) and DLP (256±81mGy x cm vs. 544±83mGy x cm) but similar image quality (p=0.37 for CNR). Furthermore, image quality was similar between BMI groups (p=0.86 for CNR).

Conclusions: A CT protocol that incorporates low kV settings with a personalized (BMI-adjusted) reference amplitude for tube current modulation and iterative reconstruction enables very low radiation exposure CTA, while maintaining good image quality and high diagnostic accuracy in the assessment of PAD.

Keywords: Body mass index; CT angiography; Digital subtraction angiography; Peripheral arterial disease; Radiation exposure.

MeSH terms

Adult
Aged
Aged, 80 and over
Angiography, Digital Subtraction / methods
Angiography, Digital Subtraction / standards
Arteries / diagnostic imaging
Body Mass Index*
Computed Tomography Angiography / methods*
Computed Tomography Angiography / standards
Female
Humans
Male
Middle Aged
Peripheral Arterial Disease / diagnostic imaging*
Prospective Studies
Radiation Dosage
Radiation Exposure
Radiographic Image Interpretation, Computer-Assisted / methods
Signal-To-Noise Ratio