In FLASH-mode coronary PCCT, heart rate variability, not mean heart rate, was the strongest predictor of reduced diagnostic image quality.
Both heart rate and heart rate variability were associated with motion artifacts, but only heart rate variability independently predicted lower image quality.
These findings support the idea that scan mode selection for high-pitch coronary PCCT should pay close attention to rhythm stability, not just absolute heart rate.
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Figure 1. Illustration of diagnostic quality scores of the right coronary artery (RCA) on radial reconstructions of coronary photon-counting computed tomography angiography
Source: Rotkopf et al., International Journal of Cardiovascular Imaging, 2023, Open Access
Protocol
Detail | Value |
|---|
Scanner | NAEOTOM Alpha |
Scan area | Heart |
Scan mode | QuantumPlus ECG-gated ultra-fast high-pitch (FLASH) |
Scan direction | High-pitch spiral |
Tube voltage [kV] | 120 |
Effective mAs [mAs] | n.a. |
IQ level | n.a. |
Dose modulation | CARE Dose4D |
CTDIvol [mGy] | 3.0 ± 1.1 |
DLP [mGy*cm] | 56.5 ± 24.8 |
Rotation time [s] | 0.25 |
Pitch | FLASH / ultra-fast high-pitch |
Matrix | 512 × 512 |
Field of view | Variable, covering whole heart and coronary vessels |
Slice collimation [mm] | 144 x 0.4 |
Slice width [mm] | 0.6 |
Reconstruction increment [mm] | 0.4 |
Reconstruction kernel | Bv40 |
Calcium scoring | Low-dose non-contrast cardiac CT before CTA |
Contrast agent | Imeron 400 |
Contrast volume | 80 mL |
Flow rate | 4–5 mL/s |
Saline chaser | 20 mL NaCl 0.9% |
Patient preparation | IV metoprolol 5–10 mg and sublingual nitroglycerin 0.4–0.8 mg if not contraindicated |
Heart rate assessment | HR during scan |
Heart rate variability | SD of the 5 heartbeats before scan |
Rotkopf LT, Froelich MF, Riffel P, et al. Influence of heart rate and heart rate variability on the feasibility of ultra-fast, high-pitch coronary photon-counting computed tomography angiography. Int J Cardiovasc Imaging. 2023;39(5):1065–1073.
