UHR photon-counting CCTA achieved high diagnostic accuracy for detecting CAD in a high-risk TAVR population, despite severe calcification and prior stent placement.
Image quality was excellent overall, with 97.8% of coronary segments rated diagnostic and 79% rated good or excellent.
The study suggests that UHR PCCT may help reduce unnecessary invasive coronary angiography in pre-TAVR patients by providing reliable noninvasive coronary assessment.
Figure 2. Ultrahigh-resolution (UHR) coronary CT angiography (CCTA) in an 85-year-old man before transcatheter aortic valve replacement. Despite a stent in the right coronary artery and very severe coronary sclerosis with an Agatston score of 4162, diagnostic visualization of the coronary arteries succeeded, and obstructive coronary artery disease was excluded on CT images. (A) Three-dimensional cinematic rendering of the heart. The stent (arrowhead) is visible in the middle segment of the right coronary artery. (B) UHR CCTA with 0.2-mm axial sections. The lumen (arrow) of the severely calcified distal left anterior descending artery can be assessed without artifacts. (C) Curved multiplanar reformations of the right coronary artery with a diagnostic display of the stent lumen (arrowhead). (D) Invasive coronary angiography enables exclusion of in-stent stenosis.
Source: Hagar et al., Radiology, 2023, CC BY 4.0
Protocol
Detail | Value |
|---|
Scanner | NAEOTOM Alpha |
Software | VA50 |
Scan area | Heart |
Scan protocol | Unenhanced calcium scoring scan, followed by contrast-enhanced ECG-gated UHR CCTA, followed by aortoiliac CTA |
Scan mode | Quantum HD Retrospective ECG-gated dual-source helical |
Tube voltage [kV] | 120 or 140 |
Effective mAs [mAs] | n.a. |
IQ level | n.a. |
Dose modulation | Automated tube current modulation and ECG pulsing 20–80% of R-R interval |
CTDIvol [mGy] | 67.7 ± 19.2 for UHR CCTA |
DLP [mGy*cm] | 936 ± 278 for UHR CCTA |
Effective dose [mSv] | 13.3 ± 4.2 for UHR CCTA |
Rotation time [s] | 0.25 |
Pitch | 0.2 |
Matrix | 1024 × 1024 |
Field of view [mm] | 180 × 180 |
Slice collimation [mm] | 120 × 0.2 |
Slice width [mm] | 0.2 |
Reconstruction increment [mm] | 0.1 |
Reconstruction kernel | Bv56 |
Iterative reconstruction | QIR3 |
Contrast agent | Iopromide, Ultravist 370 mg iodine/mL |
Contrast volume | 70 mL contrast + 30 mL contrast mixed with 40 mL saline |
Flow rate | 5.0 mL/s |
Bolus triggering | Bolus tracking |
Patient preparation | No beta-blockers, no nitroglycerin |
Coronary calcium scoring | Unenhanced scan before UHR CCTA |
Hagar MT, Soschynski M, Saffar R, et al. Accuracy of Ultrahigh-Resolution Photon-counting CT for Detecting Coronary Artery Disease in a High-Risk Population. Radiology. 2023;307(5).
