Low-radiation and high image quality coronary computed tomography angiography in “real-world” unselected patients

Abstract

AIMTo determine the radiation dose and image quality in coronary computed tomography angiography (CCTA) using state-of-the-art dose reduction methods in unselected “real world” patients.METHODSIn this single-centre study, consecutive patients in sinus rhythm underwent CCTA for suspected coronary artery disease (CAD) using a 320-row detector CT scanner. All patients underwent the standard CT acquisition protocol at our institute (Morriston Hospital) a combination of dose saving advances including prospective electrocardiogram-gating, automated tube current modulation, tube voltage reduction, heart rate reduction, and the most recent novel adaptive iterative dose reconstruction 3D (AIDR3D) algorithm. The cohort comprised real-world patients for routine CCTA who were not selected on age, body mass index, or heart rate. Subjective image quality was graded on a 4-point scale (4 = excellent, 1 = non-diagnostic).RESULTSA total of 543 patients were included in the study with a mean body weight of 81 ± 18 kg and a pre-scan mean heart rate of 70 ± 11 beats per minute (bpm). When indicated, patients received rate-limiting medication with an oral beta-blocker followed by additional intravenous beta-blocker to achieve a heart rate below 65 bpm. The median effective radiation dose was 0.88 mSv (IQR, 0.6-1.4 mSv) derived from a Dose Length Product of 61.45 mGy.cm (IQR, 42.86-100.00 mGy.cm). This also includes what we believe to be the lowest ever-reported radiation dose for a routine clinical CCTA (0.18 mSv). The mean image quality (± SD) was 3.65 ± 0.61, with a subjective image quality score of 3 (“good”) or above for 93% of patient CCTAs.CONCLUSIONCombining a low-dose scan protocol and AIDR3D with a 320-detector row CT scanner can provide high quality images at exceptionally low radiation dose in unselected patients being investigated for CAD.

Higher Iodine Concentration Enables Radiation Dose Reduction in Coronary CT Angiography

“…In the BMI approximation (24.7 § 2.2 vs. 24.8 § 2.9 kg/ m 2 ), the ED in the FLD group was significantly lower (2.6 § 0.8 mSv) when compared to the Ko study (19). For a total of 28 patients with a BMI 25 kg/m 2 (26.8 § 1.1 kg/m 2 ) in the FLD group, the ED (0.80 § 0.13 mSv) was significantly lower than that the study conducted by Rochitte et al (20) (BMI = 27 kg/m 2 and ED = 3.16 [2.82-3.63 mSv]) and similar with recent studies in which the BMIs of the patients were unknown (0.71-0.88 mSv) (12,21,22). Although decreases in radiation dose were associated with a concomitant increase in image noise and a possibility of reduction in overall image quality, we succeeded in maintaining a constant SNR and CNR on axial images or CPR reconstructions enabling adequate depiction of the coronary in the FLD group by increasing the iodine delivery rate (IDR).…”

Ten things to know about ten imaging studies: A preventive cardiology perspective (“ASPC top ten imaging”)

“…[ 37 , 38 ]. Procedure Invasiveness Patient radiation exposure * Contemporary coronary artery calcium CT (CAC) Noninvasive, no contrast ~ 1 mSv [ 39 , 40 , 41 ] Contemporary coronary CT angiography (CCTA) Requires injection of contrast material (i.e., iodine) 1.0 - 5 mSv ⁎⁎ [ 42 , 43 , 44 , 45 ] Cardiac ultrasound / echocardiogram Noninvasive. If unable to physically exercise, then dobutamine may be injected to mimic exercise.…”

The Incremental Role of Coronary Computed Tomography in Chronic Coronary Syndromes

“…For example, an effective dose of 8.3 ± 3.4 mSv was reported for 320-detector-row CT scanners, due to tube current and X-ray emission modification based on the patient's body size [22]. Several years later, an even lower radiation dose, till less than 1 mSV, was achieved with faster gantry rotation times and other technical improvements, though providing an excellent image quality over a wide range of body sizes and heart rates at lower radiation dose [23,24]. Table 2 underlines the different radiation exposure ranges for different CT modalities.…”