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

• Published in: European journal of radiology 2017-08, Vol.93, p.149-156
• Main Authors: Schreiner, Markus M, Platzgummer, Hannes, Unterhumer, Sylvia, Weber, Michael, Mistelbauer, Gabriel, Loewe, Christian, Schernthaner, Ruediger E
• Format: Article
• Language: English
• Subjects: 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; CT angiography; Digital subtraction angiography; Female; Humans; Male; Middle Aged; Peripheral arterial disease; Peripheral Arterial Disease - diagnostic imaging; Prospective Studies; Radiation Dosage; Radiation Exposure; Radiographic Image Interpretation, Computer-Assisted - methods; Radiology; Signal-To-Noise Ratio
• ISSN: 0720-048X; 1872-7727
• 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 80 kV 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 ± 0.55 mGy vs. 4.18 ± 0.62 mGy) and DLP (256 ± 81 mGy x cm vs. 544 ± 83 mGy 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.