RATIONALE AND OBJECTIVES: Concerns for patient's risk of radiation-induced cancer have increased demand for reduced-dose coronary computed tomography angiography (CCTA). Previous comparisons of full and reduced-dose CCTA were not conclusive, because results were compared in different groups of patients. Presented here are results in patients examined by a widely used full dose CCTA protocol and a new low-dose alternative. MATERIALS AND METHODS: Standard full-dose and low-dose CCTA with tube voltages of 120/100 kV were applied on 70 patients with intermediate probability of coronary artery disease (CAD). Both protocols used prospective electrocardiogram-gated acquisition on a 320-detector row CT scanner, whereas at low-dose CCTA the phase window was increased from 10% to 75% of R-R interval. RESULTS: Despite a mean dose reduction of 80%, from 4.9 ± 0.98 to 0.98 ± 0.24 mSv, visual image quality was not significantly affected at the low-dose protocol. Contrast level, image noise, and CNR for both protocols were similar in the majority of coronary segments. CNR for standard and low-dose protocol were 23.7 ± 17.1 and 23.2 ± 26.8, P = NS. Correlation between visual image quality and heart rate variability was strong at low dose: r = -0.58, P = .01, and absent at full dose: r = -0.07, P = .77. CONCLUSION: Image quality of blood vasculature is generally not affected by 80% CCTA dose reduction applied to standard prospective electrocardiogram-gated acquisition. The performance at the low-dose protocol owes to the increased phase window, enhancing image quality at the cost of sensitivity to heart rate variability as compared with standard CCTA.
RATIONALE AND OBJECTIVES: Concerns for patient's risk of radiation-induced cancer have increased demand for reduced-dose coronary computed tomography angiography (CCTA). Previous comparisons of full and reduced-dose CCTA were not conclusive, because results were compared in different groups of patients. Presented here are results in patients examined by a widely used full dose CCTA protocol and a new low-dose alternative. MATERIALS AND METHODS: Standard full-dose and low-dose CCTA with tube voltages of 120/100 kV were applied on 70 patients with intermediate probability of coronary artery disease (CAD). Both protocols used prospective electrocardiogram-gated acquisition on a 320-detector row CT scanner, whereas at low-dose CCTA the phase window was increased from 10% to 75% of R-R interval. RESULTS: Despite a mean dose reduction of 80%, from 4.9 ± 0.98 to 0.98 ± 0.24 mSv, visual image quality was not significantly affected at the low-dose protocol. Contrast level, image noise, and CNR for both protocols were similar in the majority of coronary segments. CNR for standard and low-dose protocol were 23.7 ± 17.1 and 23.2 ± 26.8, P = NS. Correlation between visual image quality and heart rate variability was strong at low dose: r = -0.58, P = .01, and absent at full dose: r = -0.07, P = .77. CONCLUSION: Image quality of blood vasculature is generally not affected by 80% CCTA dose reduction applied to standard prospective electrocardiogram-gated acquisition. The performance at the low-dose protocol owes to the increased phase window, enhancing image quality at the cost of sensitivity to heart rate variability as compared with standard CCTA.
Authors: Sock Keow Tan; Chai Hong Yeong; Raja Rizal Azman Raja Aman; Kwan Hoong Ng; Yang Faridah Abdul Aziz; Kok Han Chee; Zhonghua Sun Journal: Br J Radiol Date: 2018-03-29 Impact factor: 3.039
Authors: M C Williams; N W Weir; S Mirsadraee; F Millar; A Baird; F Minns; N G Uren; G McKillop; R K Bull; E J R van Beek; J H Reid; D E Newby Journal: Clin Radiol Date: 2013-07-06 Impact factor: 2.350