This prospective study compared 0.2-mm ultra-high-resolution (UHR) PCCT with 1-mm standard-resolution 40-keV VMI for abdominal CTA in 94 participants, equally divided between full-dose and low-dose protocols. Standard-resolution 40-keV VMI provided significantly higher SNR and CNR than all UHR reconstructions.
UHR reconstruction nevertheless improved vessel sharpness, particularly with the sharper Bv56 and Bv60 kernels, but the associated increase in image noise reduced overall image quality. The smoother Bv48 UHR reconstruction provided the best balance, with overall quality comparable to standard-resolution 40-keV VMI.
Importantly, abdominal artery visibility was broadly comparable across full- and low-dose reconstructions. The authors therefore favor 1-mm low-dose 40-keV VMI for routine abdominal CTA, while 0.2-mm UHR Bv48 may be valuable when very thin slices and visualization of distal vascular segments are specifically required.
Access publication
Figure 5. Representative example of two participants who both underwent full-dose scan. A A 71-year man with a BMI of 19.7 kg/m2 underwent abdominal CTA using a FD protocol with CTDIvol, DLP, SSDE, and effective dose of 6.23 mGy, 212.0 mGy·cm, 9.06 mGy, and 3.18 mSv, respectively. The data were reconstructed into FD_UHR_Bv48, FD_UHR_Bv56, FD_UHR_Bv60, FD_SR_Bv40 images, respectively. The UHR images have higher image noise, but better vessel sharpness. The overall quality of FD_UHR_Bv48, and FD_SR_Bv40 images are comparable. The FD_UHR_Bv56 and FD_UHR_Bv60 images presented better vessel sharpness than but were damaged by higher image noise. B–D Another 57-year woman with a BMI of 20.8 kg/m.2 underwent abdominal CTA using a FD protocol with CTDIvol, DLP, SSDE, and effective dose of 4.06 mGy, 111.0 mGy·cm, 6.25 mGy, and 1.67 mSv, respectively. The data were reconstructed into FD_UHR_Bv48, and FD_SR_Bv40 images, respectively. B The left gastric artery is only visible in axial FD_UHR_Bv48 images (solid arrow), and the soft tissue between the abdominal aorta and celiac trunk were better depicted (open arrow). C There were more visible vascular segments of left renal artery in coronal FD_UHR_Bv48 images than FD_SR_Bv40 images (solid arrow). D The left renal artery can be better visualized to the more distal vascular segments in volume-rendered FD_UHR_Bv48 images than FD_SR_Bv40 images (solid arrow). The volume-rendered FD_UHR_Bv48 images allowed more visible vascular segments of superior mesenteric artery (open arrow).
Protocol
Detail | Value |
|---|
Scanner | NAEOTOM Alpha |
Software | Syngo.CT VA50-SP1; syngo.via VB60 |
Scan area | Abdominal CTA |
Scan mode | UHR |
Acquisition mode | PCCT |
Tube voltage [kV] | 120 |
Effective mAs [mAs] | CARE Dose4D automatic |
IQ level | 145 full dose; 90 low dose |
Dose modulation | CARE Dose4D |
CTDIvol [mGy] | Protocol-dependent; significantly lower with low-dose protocol |
DLP [mGy·cm] | Protocol-dependent; significantly lower with low-dose protocol |
Temporal resolution [ms] | n.a. |
Rotation time [s] | 0.50 |
Pitch | 0.8 |
Matrix | Automatically adjusted |
Field of view [mm] | Automatically adjusted |
Detector slice collimation | 120 × 0.2 mm |
Acquisition slice thickness | 0.2 mm |
Slice width [mm] | UHR: 0.2; SR: 1.0 |
Reconstruction increment [mm] | UHR: 0.2; SR: 0.7 |
Reconstruction kernel | UHR: Bv48, Bv56, Bv60; SR: Bv40 |
Iterative reconstruction | UHR: QIR 4; SR: QIR 3 |
Reconstruction | UHR polychromatic vs standard-resolution 40-keV VMI |
Reconstruction comparison | FD_UHR_Bv48, FD_UHR_Bv56, FD_UHR_Bv60, FD_SR_Bv40, LD_UHR_Bv48, LD_SR_Bv40 |
Contrast agent | Ultravist 370 |
Contrast volume | 1.5 mL/kg |
Saline flush | n.a. |
Injection rate | 3.0 mL/s |
Bolus triggering | Abdominal aorta |
Arterial phase | 12-s delay after aortic enhancement |
Additional reconstructions | Axial, coronal, volume-rendered images |
Key Results
Parameter | Main finding |
|---|
Study population | 94 participants; 47 full dose + 47 low dose |
SNR / CNR | Significantly higher with 1-mm 40-keV VMI than UHR, P < 0.001 |
Vessel sharpness | Highest with UHR Bv56/Bv60, but with substantially more noise |
Best UHR balance | 0.2-mm Bv48 provided comparable overall quality to 40-keV VMI |
Artery visibility | No significant overall difference among the six reconstruction series |
Preferred strategy | Low-dose 1-mm 40-keV VMI for routine CTA; 0.2-mm UHR Bv48 when thinner slices are required |
Source:
Zhang H, Xing Y, Wang L, Hu Y, Xu Z, Chen H, Lu J, Yang J, Ding B, Hu W, Zhong J. Ultra-High-Resolution Photon-Counting Detector CT Benefits Visualization of Abdominal Arteries: A Comparison to Standard-Reconstruction. Journal of Imaging Informatics in Medicine. 2025;38:1891–1903. doi:10.1007/s10278-024-01232-5.
