For assessments of head and neck vasculature, rising analysis means that ultra-high decision (UHR) photon counting detector computed tomography angiography (PCD CTA) could provide key benefits over energy-integrating detector CTA (EID CTA).
For the possible examine, not too long ago revealed within the American Journal of Roentgenology, researchers reviewed information from 103 sufferers (imply age of 61.3) who had head and neck UHR PCD CTA, and in contrast 0.2 mm slice thickness UHR reconstructions of various kernel sharpness to an 0.8 mm slice thickness reference reconstruction at Bv40 kernel sharpness. Using a Likert scale of 1-5 with 5 denoting the very best high quality), two radiologists offered impartial assessments of the reconstructed photos with respect to vessel visualization, gentle plaque delineation and discount of blooming artifacts, in line with the examine.
Compared to the median vessel sharpness of 100.9 HU/mm reported for the reference reconstruction, the researchers famous 121.6 HU/mm for UHR PCD set at a Bv76 kernel and 134.7 HU/mm for UHR PCD at a Bv80 kernel. The examine authors additionally famous that the UHR PCD kernel settings of Bv76 and Bv80 generated a Likert scale score of 5 for small vessel visualization from reviewing radiologists compared to 1 for the reference reconstruction.
Right here one can see discount of a stent blooming artifact and enhanced visualization of the lumen in ultra-high decision photon-counting CTA reconstructions (B and C) compared to the reference picture reconstruction (A). (Photos courtesy of the American Journal of Roentgenology.)
For median stent blooming artifact discount and median gentle plaque delineation, the reference reconstruction was rated with a 1 on the Likert scale by the reviewing radiologist in distinction to a 5 rating for UHR PCD kernel settings of Bv76 and Bv80, in line with the examine authors.
“PCD CTA of the top and neck in UHR mode (slice thickness, 0.2 mm) diminished blooming artifact from calcified plaques or stents whereas bettering visualization of sentimental plaques and small vessels as compared with reference reconstructions reflecting standard medical protocols,” wrote lead examine writer Naying He, M.D., Ph.D., who’s affiliated with the Division of Radiology at Ruijin Hospital and the Shanghai Jiao College Faculty of Drugs in Shanghai, China, and colleagues.
Noting that blooming artifacts on standard CTA can result in overestimation of the scale of calcifications and stents, the researchers famous will increase of the median proper inside carotid artery C2 luminal diameter from 3.8 mm for the reference reconstruction to 4.1 mm and 4.9 mm for the UHR PCD kernel settings of Bv48 and Bv80 respectively.
“Within the current examine, because the vascular kernel energy elevated, the C2 lumen diameter progressively elevated, indicating a progressive discount in blooming artifacts (in step with prior research of the UHR PCD CTA for coronary artery analysis),” added He and colleagues.
Three Key Takeaways
1. Improved vessel visualization and plaque delineation. Extremely-high decision (UHR) photon counting detector computed tomography angiography (PCD CTA) considerably enhances the visualization of small vessels and gentle plaques in comparison with standard energy-integrating detector (EID) CTA. The examine famous increased Likert scale rankings for UHR PCD settings (Bv76 and Bv80), scoring 5 versus 1 for standard protocols.
2. Discount in blooming artifacts. UHR PCD CTA at 0.2 mm slice thickness and elevated kernel strengths reduces blooming artifacts from calcified plaques and stents. This results in extra correct evaluation of vessel luminal diameters with elevated readability and diminished overestimation of stent and calcification sizes.
3. Commerce-offs in picture noise and SNR. Though UHR PCD CTA improves vessel visualization, it comes at the price of elevated picture noise and a decrease signal-to-noise ratio (SNR), notably at increased kernel strengths (e.g., Bv80). The examine suggests choosing kernels primarily based on medical context to assist obtain an acceptable stability between picture high quality and noise.
Whereas the reviewing radiologist rated the upper UHR PCD kernel settings of Bv76 and Bv80 as offering optimum gentle plaque visualization, the examine authors famous that compared to the reference reconstruction, the UHR PCD Bv80 kernel setting had over 10 occasions the median picture noise (60.4 HU vs. 5.7 HU) and a virtually tenfold discount within the signal-to-noise ratio (SNR) (5.7 vs. 56.8).
“Accordingly, in follow, a kernel might be chosen primarily based on the given medical context (e.g., number of a powerful kernel within the presence of a stent),” identified He and colleagues.
(Editor’s word: For associated content material, see “Can Polyenergetic Reconstruction Assist Resolve Streak Artifacts in Photon Counting CT?,” “Meta-Evaluation Reveals Superiority of CT Angiography Over SPECT and Purposeful Testing for Obstructive CAD” and “5-12 months Examine Reveals Vital Overuse of CT Angiography within the ER.”)
In regard to check limitations, the authors acknowledged an absence of comparability between PCD CT and vitality integrating detector (EID) CT, and the usage of one PCD CT gadget to carry out all PCD CTA exams. The researchers conceded that variable matrix dimension throughout kernels could have had an influence on picture noise evaluation. In addition they prompt doable bias with the evaluation of examination reconstructions being carried out in a single session.
