The international journal of cardiovascular imaging最新文献

Solid-state detector single photon emission computed tomography (SPECT) enables the acquisition of dynamic data for calculation of myocardial blood flow (MBF) and myocardial flow reserve (MFR). Here, we report about our experiences on routine clinical use and robustness using Tc-99 m-sestamibi and Tc-99 m-tetrofosmin. 307 patients underwent dynamic list-mode myocardial perfusion imaging (MPI) and standard static MPI for clinical workup of coronary artery disease on a dedicated cardiac SPECT camera. After exclusion of 33 scans, 274 scans were eligible for MBF and MFR calculation using a 1-tissue-compartment model. Attenuation correction was performed for all patients using an external computed tomogram. Patients underwent stress-only scans, both stress and rest scans or rest-only scans using Tc-99 m-tetrofosmin or Tc-99 m-sestamibi. 30 patients without known cardiovascular comorbidities and without perfusion defect on static scans were compared in a sub analysis. Global stress myocardial blood flow (MBF) was significantly higher than rest MBF (2.3 vs. 1.1 ml/min/g; p < 0.001), and showed a high variability among individuals. Global myocardial flow reserve (MFR) was 2.1 (range 0.5-7.8). An analysis of 30 patients without known cardiovascular comorbidities yielded similar stress MBF measures for Tc-99 m-sestamibi and Tc-99 m-tetrofosmin (3.1 ± 1.2 vs. 2.8 ± 0.9 ml/min/g; p = 0.429). The use of attenuation correction lead to systematically lower MBF measures. Patients who underwent a one-day protocol had notably higher rest MBF (1.2 ± 0.5 vs. 1.0 ± 0.46 ml/min/g; p = 0.009) and consequently a lower MFR. Summed defect scores from standard static scans and presence of cardiovascular comorbidities negatively impacted MBF and MFR. Quantitative SPECT MBF and MFR in a clinical routine setting yields flow measures in range of expectation at an albeit wide range and is comprehensibly linked with results from standard static scan and patients history of cardiovascular diseases. Use of one-day protocols and attenuation correction systematically alters quantitative results. However, SPECT-derived MBF and MFR lack clinical reliability due to less validated reference ranges and high inter-individual variability.

This study aims to evaluate the implementation of concomitant CAD assessment on pre-TAVI (transcatheter aortic valve implantation) planning CTA (CT angiography) aided by CT-FFR (CT-fractional flow reserve) [The CT2TAVI protocol] and investigates the incremental value of CT-FFR to coronary CT angiography (CCTA) alone in the evaluation of patients undergoing CT2TAVI. This is a prospective observational real-world cohort study at an academic health system on consecutive patients who underwent CTA for TAVI planning from 1/2021 to 6/2022. This represented a transition period in our health system, from not formally reporting CAD on pre-TAVI planning CTA (Group A) to routinely reporting CAD on pre-TAVI CTA (Group B; CT2TAVI protocol). All CTAs were retrospective ECG-gated using a dual source 192 slice CT scanner without nitrate or intravenous beta blocker premedication. We assessed downstream ICA and revascularization pre-TAVI and clinical outcomes 30 days and 1 year post-TAVI in both groups. 307 patients were included with 199 patients in Group A and 108 patients in Group B. In Group B, ICA was performed pre-TAVI in only 40.7% of patients. The use of CT-FFR, which was primarily aimed at identifying hemodynamically significant proximal vessel disease, helped avoid downstream invasive testing for 60.5% (23/38) of patients who were deemed to have obstructive proximal vessel disease using CCTA alone or had one or more uninterpretable proximal segments using CCTA. All-cause mortality, cardiovascular mortality, myocardial infarction and need for revascularization at 1-year post-TAVI were comparable between groups with a higher trend toward heart failure hospitalizations in Group A. Routine ICA can safely be deferred pre-TAVI, with the CT2TAVI strategy using modern CT scanners aided by CT-FFR analysis.

Myocardial extracellular volume fraction (ECV) measured via MRI serves as a quantitative indicator of myocardial fibrosis. However, accurate measurement of ECV using MRI in the presence of AF is challenging. Meanwhile, CT could be a promising alternative tool for measuring ECV regardless of sinus rhythm or AF. The purpose of this study was to assess the reliability of estimating ECV using CT in patients with AF by comparing it with MRI-derived ECV. Forty-two patients (n = 42) with AF underwent cardiac CT a median of 12 days before catheter ablation, and cardiac MRI a median of 1 day after catheter ablation. Myocardial ECV measured by CT and MRI was compared. Pre-ablation CT scan was performed in the presence of AF in 25 patients, with the remaining 17 in sinus rhythm (SR). All patients were in SR at the time of MRI post ablation. The average of CT-derived ECVs was 0.277 ± 0.022 and that of MRI-derived ECVs was 0.282 ± 0.019 in patients with AF. The average of CT-derived ECVs was 0.268 ± 0.025 and that of MRI-derived ECVs was 0.278 ± 0.025 in patients with SR at the time of the CT scan. CT and MRI were in good agreement with mean differences of -0.0048 ± 0.027 in AF and - 0.0095 ± 0.0354 in SR. CT-derived ECV in the presence of AF measured before ablation showed good agreement with ECV by MRI in SR after ablation. CT-ECV estimations are reliable and feasible in patients with AF.

Parametric mapping has become a standard of care technique for the non-invasive assessment of myocardial edema and fibrosis. Conventional MOLLI-based T1 mapping is susceptible to many confounding effects particularly in the pediatric population. The requirement for compliant breath holds is a major limitation for younger or more ill patients. The advent of free-breathing SASHA-based multi-parametric mapping with motion correction therefore offers a significant advantage in pediatric cohorts. With IRB approval and consent/assent, children and adults with congenital heart disease underwent both conventional breath-held MOLLI-based T1 and T2 TrueFISP mapping as well as free-breathing multi-parametric SASHA assessment in the context of a clinically indicated study on a 1.5T magnet. A total of 71 subjects with mean age of 19.3 ± 8.6 years were scanned. Free-breathing multiparametric SASHA T1 and T2 values were moderately correlated with breath-held MOLLI/T2p-bSSFP (r = 0.52). Importantly free-breathing SASHA-based T1 maps were able to discriminate between patients with late gadolinium enhancement with a statistically significant difference in mean T1 values (p = 0.03). Free-breathing multiparametric SASHA allows for reliable myocardial characterization with moderate correlation to conventional breath-held T1 and T2 mapping techniques in a small and heterogenous sample of pediatric and congenital cardiac subjects.

Artificial intelligence-based quantitative coronary angiography (AI-QCA) was introduced to address manual QCA's limitations in reproducibility and correction process. The present study aimed to assess the performance of an updated AI-QCA solution (MPXA-2000) in lesion detection and quantification using manual QCA as the reference standard, and to demonstrate its superiority over visual estimation. This multi-center retrospective study analyzed 1,076 coronary angiography images obtained from 420 patients, comparing AI-QCA and visual estimation against manual QCA as the reference standard. A lesion was classified as 'detected' when the minimum lumen diameter (MLD) identified by manual QCA fell within the boundaries of the lesion delineated by AI-QCA or visual estimation. The detected lesions were evaluated in terms of diameter stenosis (DS), MLD, and lesion length (LL). AI-QCA accurately detected lesions with a sensitivity of 93% (1705/1828) and showed strong correlations with manual QCA for DS, MLD, and LL (R² = 0.65, 0.83 and 0.71, respectively). In views targeting the major vessels, the proportion of undetected lesions by AI-QCA was less than 4% (56/1492). For lesions in the side branches, AI-QCA also demonstrated high sensitivity (> 92%) in detecting them. Compared to visual estimation, AI-QCA showed significantly better lesion detection capability (93% vs. 69%, p < 0.001), and had a higher probability of detecting all lesions in images with multiple lesions (86% vs. 33%, p < 0.001). The updated AI-QCA demonstrated robust performance in lesion detection and quantification without operator intervention, enabling reproducible vessel analysis. The automated process of AI-QCA has the potential to optimize angiography-guided interventions by providing quantitative metrics.

The use of conventional contrast agents in computed tomography (CT) and magnetic resonance (MR) imaging is often limited in patients with chronic kidney disease (CKD) due to potential nephrotoxicity. Ferumoxytol, originally developed for iron supplementation, has emerged as a promising alternative MR contrast agent that is safer for patients with CKD. This study aims to present our center's experience with ferumoxytol as a contrast agent in CKD patients. We retrospectively reviewed 24 MR imaging studies of the chest, abdomen, and pelvis performed in CKD patients at our center. All patients were deemed suitable for ferumoxytol administration, receiving a dose of 4 mg/kg with post-injection monitoring. The imaging quality of the ascending, descending, suprarenal and infrarenal aortic segments was assessed by three independent observers using a qualitative scoring system (nondiagnostic, poor vascular definition, good vascular definition, and excellent vascular definition). Quantitative analyses, including signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and heterogeneity index, were also performed. No adverse reactions to ferumoxytol were observed. Of the 72 vascular segments evaluated, 90.8% of the images were rated as excellent vascular definition, and 9.2% were rated as good vascular definition. Inter-observer agreement was substantial (k = 0.647), with no statistically significant differences in ratings between observers. Ferumoxytol is a safe and effective alternative to conventional contrast agents for MR vascular imaging, particularly in patients with renal insufficiency. These findings support its selective use in appropriate clinical scenarios, offering a reliable imaging option for CKD patients.

Dynamic chest radiography (DCR) can estimate haemodynamic parameters in heart failure (HF). However, no studies have evaluated its ability to determine cardiac systolic function in HF. This experimental study investigates the correlation between left ventricular (LV) ejection fraction (LVEF) and DCR image parameters in HF. Ninety-one patients with acute HF (median age, 58 years; males, 75%) (cardiologist diagnosis using the Framingham criteria) underwent DCR and transthoracic echocardiography after treatment for the uncompensated phase of HF. The LV apex pixel value (PV) change was measured by DCR. Correlations between the PV change and LVEF, as well as sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) of DCR, were evaluated. LVEF and LV apex PV change were correlated in all patients (R = 0.428, P < 0.001) and in patients with LVEF < 50% (n = 38; R = 0.355, P = 0.029), < 40% (n = 31; R = 0.343, P = 0.059), and < 30% (n = 23; R = 0.321, P = 0.135). There was no significant correlation for patients with LVEF ≥ 50% (n = 53; R = - 0.004, P = 0.980). The LV apex PV change rate cutoff values for identifying LVEF < 50%, < 40%, and < 30% were 9.3% (AUC: 0.761, sensitivity: 0.698, specificity: 0.789, P < 0.001), 5.5% (AUC: 0.765, sensitivity: 0.883, specificity: 0.645, P < 0.001), and 5.5% (AUC: 0.767, sensitivity: 0.838, specificity: 0.696, P < 0.001), respectively. DCR may be useful to identify LV systolic dysfunction based on LVEF in acute HF.