the aims of the study were to identify subclinical global systolic function abnormalities and evaluate influencing factors associated with left ventricular (LV) strain parameters in hypertensive subjects using cardiovascular magnetic resonance imaging feature tracking (CMR-FT). The study enrolled 57 patients with essential hypertension (mean age: 43.04 ± 10.90 years; 35 males) and 26 healthy volunteers (mean age: 38.69 ± 10.44 years; 11 males) who underwent clinical evaluation and CMR examination. Compared with controls, hypertensive patients had significantly impaired myocardial strain values while ejection fraction (EF) did not differ. After multivariate regression analyses adjustment for confounders, the global radial strains (GRS) was independently associated with the mean arterial pressure (MAP) and left ventricular mass index (LVMI) (β = −0.219, p = 0.009 and β = −0.224, p = 0.015, respectively; Adjusted R 2 = 0.4); the global circumferential strains (GCS) was also independently associated with the MAP and LVMI (β = 0.084, p = 0.002 and β = 0.073, p = 0.01, respectively; Adjusted R 2 = 0.439); the global longitudinal strains (GLS) was independently associated with the Age and MAP (β = 0.065, p = 0.021 and β = 0.077, p = 0.009, respectively; Adjusted R 2 = 0.289). Myocardial strain can early detect the myocardial damage and may be an appropriate target for preventive strategies before abnormalities of EF. Essential hypertension is defined as a rise in blood pressure which can increase risks for cerebral, cardiac, and renal events with unknown reason 1. Hypertension remains deserving for more attention since it is a potent risk factor for cardiovascular diseases and it may brings considerable morbidity and mortality 1-4. Given the prevalence of hypertension in the population, early identifying subclinical left ventricular (LV) systolic dysfunction among hypertensive subjects might have an important role in assessing the prognosis and choosing treatment strategies. Strain imaging has emerged as a sensitive and powerful tool to detect early and subtle myocardial dysfunction in various cardiac diseases, and may provide a novel method for LV risk assessment in hypertensive patients 5-7. Myocardial strain was first used by cardiovascular magnetic resonance (CMR) tagging in 1988 8. CMR tagging has been the most available and reproducible method to quantify the myocardial deformation and remains the reference standard for evaluating myocardial strain 9,10. However, CMR tagging needs to acquire additional sequences and its post processing is time-consuming. The spatial resolution of tagging is quite low, which is another limitation of tagging. Therefore, CMR tagging has not yet been widely applied in clinical circumstances. Speckle tracking echocardiography (STE) has solved these issues to a large extent, but it is still limited by the observer dependency, signal noise, angle dependency, inadequate acoustic windows and poor image quality 11-13. Cardiovascular magnetic resonance imaging feature tracking (CMR-FT), whic...
Background: This study aimed to evaluate the effects of different iterative reconstruction (IR) algorithms on coronary artery calcium (CAC) score quantification using the reduced radiation dose (RRD) protocol in an anthropomorphic phantom and in patients.Methods: A thorax phantom, containing 9 calcification inserts with varying hydroxyapatite (HA) densities, was scanned with the reference protocol [120 kv, 80 mAs, filtered back projection (FBP)] and RRD protocol (120 kV, 20-80 mAs, 5 mAs interval) using a 256-slice computed tomography (CT) scanner. Raw data were reconstructed with different reconstruction algorithms [iDose 4 levels 1-7 and iterative model reconstruction (IMR) levels 1-3]. Signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and Agatston score (AS) were calculated for each image series. The correction factor was derived from linear regression analysis between the reference image series and other image series with different parameters. Additionally, 40 patients were scanned with the RRD protocol (50 mAs) and reconstructed with FBP, iDose 4 level 4, and IMR level 2. AS was calculated for the 3-group image series, and was corrected by applying a correction factor for the IMR group. The agreement of risk stratification with different reconstruction algorithms was also analyzed.Results: For the phantom study, the iDose 4 and IMR groups had significantly higher SNR and CNR than the FBP group (all P<0.05). There were no significant differences in the total AS after comparing image series reconstructed with iDose 4 (level 1-7) and FBP (all P>0.05), while AS from the IMR (level 1-3) image series were lower than the FBP group (all P<0.05). The tube current of 50 mAs was determined for the clinical study, and the correction factor was 1.14. For the clinical study, the median AS from the iDose 4 and IMR groups were both significantly lower compared to the FBP image series [
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