Aortic dual-energy CT angiography with low contrast medium injection rate

Abstract

The contrast medium (CM) induced nephropathy required new CT imaging protocol. This study evaluated the feasibility of low contrast medium (CM) volume and injection flow using aortic dual-energy CT (DECT) angiography with nonlinear blending technique. Sixty patients were randomly assigned to two groups: control group (n = 30), single-energy CT 70 ml CM at injection rate of 5 ml/s; study group (n = 30), DECT mode, 0.5 ml per kg of patient weight CM at injection rate = (weight × 0.5 ml/kg)/(4 + scan time). Non-linear blending technique was used for dual-energy images. Mean attention, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of aorta were compared. The level of visible renal artery branches was scored. There was no significant difference between the two groups in the mean aortic attention, SNR and CNR (all P > 0.05). Significant difference was showed in CM injection rate (p < 0.001) and volume (P < 0.001). The renal artery score had no statistically significant difference (P = 0.771). Compared conventional scan and CM injection protocol, DECT with non-linear blending technique maintained the image quality of aortic CT angiography with reduced CM volume and flow rate, which could reduce the risks associated with CM injection.

Update on Cardiovascular Applications of Multienergy CT

“…This was demonstrated for coronary CT angiography in a prospective randomized trial, where the use of 35 mL of iodinated contrast material and VM images at 60 keV resulted in the same diagnostic interpretability, SNR, and CNR as with a conventional coronary CT angiogram with 80 mL of contrast agent (21). Similar techniques using low doses of contrast material have been investigated in aortic (Fig 3) and lower-extremity CT angiography (22)(23)(24). Contrast dose reduction techniques may subsequently have implications for reducing the risk for contrast-induced nephropathy, particularly in atrisk patients with marginal renal function, although this has yet to be demonstrated prospectively in the literature.…”

CT angiography of the aorta using 80 kVp in combination with sinogram‐affirmed iterative reconstruction and automated tube current modulation: Effects on image quality and radiation dose

“…For future investigations a combination of a high IDR (highly concentrated contrast medium and high injection rate), a reduced tube potential of 70–80 kVp and advanced IR technique seems to be promising to further optimize radiation and contrast medium dose in CTA. New technical developments can help to improve patient care, such as dual‐energy CT (DECT) providing virtual non‐contrast images or novel X‐ray tubes providing higher tube current time products and enable even further tube potential reduction . Initial studies regarding DECT were recently published with non‐linear blending technique leading to a significant reduction of applied contrast material in aortic CTA .…”

“…New technical developments can help to improve patient care, such as dual‐energy CT (DECT) providing virtual non‐contrast images or novel X‐ray tubes providing higher tube current time products and enable even further tube potential reduction . Initial studies regarding DECT were recently published with non‐linear blending technique leading to a significant reduction of applied contrast material in aortic CTA . However, as these techniques are not extensively available, low‐kVp examinations will remain a helpful tool to reduce either radiation dose or the amount of contrast material in order to improve patient safety.…”

Iterative reconstruction in single-source dual-energy CT angiography: feasibility of low and ultra-low volume contrast medium protocols

“…The injection rates for the study groups were calculated as: (CM volume)/ (delay time 1 exposure time). 9 The volume of follow-up saline tracer for Groups B and C was selected as 30, 40 or 50 ml, whichever is the closest to the applied CM volume. The injection rate of the saline tracer was the same as that of the CM.…”

“…A close relationship between the CM volume and occurrence of contrastinduced nephropathy has been demonstrated in the literature, 7,8 and the CM injection rate is noted to be positively correlated to the risk of intravenous access failure, particularly for patients with poor peripheral venous status. 9 Moreover, the increasing potential of radiation-induced malignancies from CT strongly motivate the reduction of radiation exposure in clinical practices. [10][11][12] Hence, minimal volume and injection rate of CM with low radiation dose is preferred for patients.…”