Roosha Parikh

Purpose of review: Photon-counting detector computed tomography (PCD-CT) is an emerging technology that addresses key limitations of conventional coronary CT angiography, including calcium blooming, stent-related artifacts, and limited spatial resolution. This review summarizes recent evidence regarding the diagnostic performance and clinical impact of PCD-CT in the evaluation of coronary artery disease (CAD) and discusses its potential role in contemporary cardiovascular imaging. Recent findings: Recent studies demonstrate that PCD-CT provides superior spatial resolution, improved contrast-to-noise ratio, and reduced blooming artifacts compared with conventional energy-integrating detector CT. Clinical investigations have shown improved diagnostic accuracy for detecting obstructive CAD, particularly in patients with heavy coronary calcification, older patients and coronary stents. Large observational studies report higher specificity, improved positive predictive value, fewer indeterminate examinations, reduced invasive coronary angiography referrals, and greater revascularization yield. Emerging applications include advanced plaque characterization, extracellular volume quantification, and ultra-low-dose radiation and contrast imaging. Summary: Current evidence suggests that PCD-CT represents a transformative advancement in noninvasive coronary imaging. Beyond improving diagnostic accuracy, PCD-CT may enhance clinical decision-making, reduce unnecessary downstream testing, and expand the role of CT in comprehensive cardiovascular assessment. Future multicenter outcome studies and standardized imaging protocols will be essential to establish its long-term clinical and economic value.

Background/Objectives: Aortic valve calcification is commonly evaluated using 3.0 mm true non-contrast (TNC) computed tomography (CT) images. This study evaluates the reproducibility of virtual non-contrast (VNC) reconstructions at different slice intervals using photon-counting detector CT (PCD-CT). Methods: In this retrospective study, we included 279 consecutive patients, who underwent PCD-CT for evaluation of native aortic valve between February 2023 and December 2023 with both TNC and VNC images at 3.0 and 1.5 mm slice intervals. Aortic valve calcium score (AVCS) and aortic valve calcium volume (AVCV) were compared between the two methods using paired t-tests. Agreement for continuous variables was assessed using inter-class coefficients (ICCs). Cohen’s Kappa (κ) was calculated to evaluate the agreement between different modalities in diagnosing severe AV calcification. Results: Compared to the standard, TNC images at 1.5 mm intervals showed higher AVCS (mean difference: −290 ± 418, p < 0.001), with high reproducibility between techniques (CS: ICC 0.969, [IQR 0.962, 0.975]). Compared with reference, VNC showed no significant differences in AVCS at either slice intervals, with excellent reproducibility (3.0 mm, ICC 0.970 [0.963, 0.976]; 1.5 mm, ICC 0.971 [0.964, 0.977]). Compared to TNC 3.0 mm, strong concordance was observed using other reconstruction techniques in assessing severe AV calcification (κ = 0.81 [95% CI: 0.74–0.88], 0.83 [95% CI: 0.76–0.90], and 0.83 [95% CI: 0.76–0.90] for TNC at 1.5 mm, VNC at 3.0 mm, and 1.5 mm, respectively), with low misclassification rates. Conclusions: Our study highlights high reproducibility in the evaluation of AVCS by VNC reconstruction at 3.0 and 1.5 mm intervals compared with reference offering a reliable alternative with an excellent diagnostic accuracy.

Background: Cardiovascular risk assessment relies heavily on coronary calcium scoring. With an emphasis on varying slice increments, this study investigates the effectiveness of true and virtual non-contrast reconstructions on photon-counting CT. Reconstruction methods’ effects on calcium severity classifications are critical to the improvement in imaging techniques. Methods: This study comprised 77 participants (mean age: 63 ± 10 years, 43% female), of whom 0 had a coronary artery calcium score (CACS) of zero. In contrast to true non-contrast (TNC) 3 × 3 mm, the reconstructions included TNC 3 × 1.5 mm, virtual non-contrast (VNC) 3 × 3 mm, and VNC 3 × 1.5 mm. Agatston units served as the basis for classifications into standard clinical diagnostic categories. Results: High concordance between acquisition types was revealed by interclass correlation values (0.97–0.99). Comparing TNC 3 × 1.5 mm reconstructions to their VNC counterparts, misclassifications were less common (Cohen Kappa = 0.94). (K = 0.83–0.85). Significant differences in the average calcium scores and rates of misclassification highlighted the impact of reconstruction methods on precise evaluations. Conclusions: VNC methods demonstrated high agreement; however, with a small rate of misclassifications as compared to the gold standard method. VNC CACS may help optimize workflows but may need differing cutoffs as compared to traditional methods.