BackgroundPreliminary semi-quantitative cardiovascular magnetic resonance (CMR) perfusion studies have demonstrated reduced myocardial perfusion reserve (MPR) in patients with angina and risk factors for microvascular disease (MVD), however fully quantitative CMR has not been studied. The purpose of this study is to evaluate whether fully quantitative CMR identifies reduced MPR in this population, and to investigate the relationship between epicardial atherosclerosis, left ventricular hypertrophy (LVH), extracellular volume (ECV), and perfusion.MethodsForty-six patients with typical angina and risk factors for MVD (females, or males with diabetes or metabolic syndrome) who had no obstructive coronary artery disease by coronary angiography and 20 healthy control subjects underwent regadenoson stress CMR perfusion imaging using a dual-sequence quantitative spiral pulse sequence to quantify MPR. Subjects also underwent T1 mapping to quantify ECV, and computed tomographic (CT) coronary calcium scoring to assess atherosclerosis burden.ResultsIn patients with risk factors for MVD, both MPR (2.21 [1.95,2.69] vs. 2.93 [2.763.19], p < 0.001) and stress myocardial perfusion (2.65 ± 0.62 ml/min/g, vs. 3.17 ± 0.49 ml/min/g p < 0.002) were reduced as compared to controls. These differences remained after adjusting for age, left ventricular (LV) mass, body mass index (BMI), and gender. There were no differences in native T1 or ECV between subjects and controls.ConclusionsStress myocardial perfusion and MPR as measured by fully quantitative CMR perfusion imaging are reduced in subjects with risk factors for MVD with no obstructive CAD as compared to healthy controls. Neither myocardial hypertrophy nor fibrosis accounts for these differences.Electronic supplementary materialThe online version of this article (10.1186/s12968-018-0435-1) contains supplementary material, which is available to authorized users.
Purpose
To develop a continuous‐acquisition cardiac self‐gated spiral pulse sequence and a respiratory motion‐compensated reconstruction strategy for free‐breathing cine imaging.
Methods
Cine data were acquired continuously on a 3T scanner for 8 seconds per slice without ECG gating or breath‐holding, using a golden‐angle gradient echo spiral pulse sequence. Cardiac motion information was extracted by applying principal component analysis on the gridded 8 × 8 k‐space center data. Respiratory motion was corrected by rigid registration on each heartbeat. Images were reconstructed using a low‐rank and sparse (L+S) technique. This strategy was evaluated in 37 healthy subjects and 8 subjects undergoing clinical cardiac MR studies. Image quality was scored (1–5 scale) in a blinded fashion by 2 experienced cardiologists. In 13 subjects with whole‐heart coverage, left ventricular ejection fraction (LVEF) from SPiral Acquisition with Respiratory correction and Cardiac Self‐gating (SPARCS) was compared to that from a standard ECG‐gated breath‐hold balanced steady‐state free precession (bSSFP) cine sequence.
Results
The self‐gated signal was successfully extracted in all cases and demonstrated close agreement with the acquired ECG signal (mean bias, –0.22 ms). The mean image score across all subjects was 4.0 for reconstruction using the L+S model. There was good agreement between the LVEF derived from SPARCS and the gold‐standard bSSFP technique.
Conclusion
SPARCS successfully images cardiac function without the need for ECG gating or breath‐holding. With an 8‐second data acquisition per slice, whole‐heart cine images with clinically acceptable spatial and temporal resolution and image quality can be acquired in <90 seconds of free‐breathing acquisition.
Purpose of Review
This article will review the current techniques in cardiac magnetic resonance imaging (CMR) for diagnosing and assessing primary valvular heart disease.
Recent Findings
The recent advancements in CMR have led to an increased role of this modality for qualifying and quantifying various native valve diseases. Phase-contrast velocity encoded imaging is a well-established technique that can be used to quantify aortic and pulmonic flow. This technique, combined with the improved ability for CMR to obtain accurate left and right ventricular volumetrics, has allowed for increased accuracy and reproducibility in assessing valvular dysfunction. Advancements in CMR technology also allows for improved spatial and temporal resolution imaging of various valves and their regurgitant or stenotic jets. Therefore, CMR can be a powerful tool in evaluation of native valvular heart disease.
Summary
The role of CMR in assessing valvular heart disease is growing and being recognized in recent guidelines. CMR has the ability to assess valve morphology along with qualifying and quantifying valvular disease. In addition, the ability to obtain accurate volumetric measurements may improve more precise management strategies and may lead to improvements in mortality and morbidity.
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