High-pitch dual-source CT coronary angiography with low volumes of contrast medium

Objectives

To assess the effect of lower volumes of contrast medium (CM) on image quality in high-pitch dual-source computed tomography coronary angiography (CTCA).

Methods

One-hundred consecutive patients (body weight 65–85 kg, stable heart rate ≤65 bpm, cardiac index ≥2.5 L/min/m²) referred for CTCA were prospectively enrolled. Patients were randomly assigned to one of five groups of different CM volumes (G₃₀, 30 mL; G₄₀, 40 mL; G₅₀, 50 mL; G₆₀, 60 mL; G₇₀, 70 mL; flow rate 5 mL/s each, iodine content 370 mg/mL). Attenuation within the proximal and distal coronary artery segments was analysed.

Results

Mean attenuation for men and women ranged from 345.0 and 399.1 HU in G₃₀ to 478.2 and 571.8 HU in G₇₀. Mean attenuation values were higher in groups with higher CM volumes (P?<?0.0001) and higher in women than in men (P?<?0.0001). The proportions of segments with attenuation of at least 300 HU in G₃₀, G₄₀, G₅₀, G₆₀ and G₇₀ were 89 %, 95 %, 98 %, 98 % and 99 %. CM volume of 30 mL in women and 40 mL in men proved to be sufficient to guarantee attenuation of at least 300 HU.

Conclusions

In selected patients high-pitch dual-source CTCA can be performed with CM volumes of 40 mL in men or 30 mL in women.

Key Points

? High-pitch dual-source coronary angiography is feasible with low contrast media volumes. ? Traditional injection rules still apply: higher volumes result in higher enhancement. ? The patient’s gender is a co-factor determining the level of contrast enhancement. ? Volumes can be reduced down to 30–40 mL in selected patients.