ULTRA HIGH FIELD MR CAROTID VESSEL WALL IMAGING: COMPARISON BETWEEN 7T AND 3T

Cardiovascular Aspects of Radiolog

Stress increases intracardiac 4D flow cardiovascular magnetic resonance -derived energetics and vorticity and relates to VO2max in Fontan patients

BACKGROUND: We hypothesize that dobutamine-induced stress impacts intracardiac hemodynamic parameters and that this may be linked to decreased exercise capacity in Fontan patients. Therefore, the purpose of this study was to assess the effect of pharmacologic stress on intraventricular kinetic energy (KE), viscous energy loss (EL) and vorticity from four-dimensional (4D) Flow cardiovascular magnetic resonance (CMR) imaging in Fontan patients and to study the association between stress response and exercise capacity. METHODS: Ten Fontan patients underwent whole-heart 4D flow CMR before and during 7.5 μg/kg/min dobutamine infusion and cardiopulmonary exercise testing (CPET) on the same day. Average ventricular KE, EL and vorticity were computed over systole, diastole and the total cardiac cycle (vorticity_volavg cycle, KEavg cycle, ELavg cycle). The relation to maximum oxygen uptake (VO2 max) from CPET was tested by Pearson's correlation or Spearman's rank correlation in case of non-normality of the data. RESULTS: Dobutamine stress caused a significant 88 ± 52% increase in KE (KEavg cycle: 1.8 ± 0.5 vs 3.3 ± 0.9 mJ, P < 0.001), a significant 108 ± 49% increase in EL (ELavg cycle: 0.9 ± 0.4 vs 1.9 ± 0.9 mW, P < 0.001) and a significant 27 ± 19% increase in vorticity (vorticity_volavg cycle: 3441 ± 899 vs 4394 ± 1322 mL/s, P = 0.002). All rest-stress differences (%) were negatively correlated to VO2 max (KEavg cycle: r = - 0.83, P = 0.003; ELavg cycle: r = - 0.80, P = 0.006; vorticity_volavg cycle: r = - 0.64, P = 0.047). CONCLUSIONS: 4D flow CMR-derived intraventricular kinetic energy, viscous energy loss and vorticity in Fontan patients increase during pharmacologic stress and show a negative correlation with exercise capacity measured by VO2 max

Improved myocardial scar characterization by super-resolution reconstruction in late gadolinium enhanced MRI

Image resolution is an important factor for accurate myocardial scar assessment from late gadolinium enhanced (LGE) MR. It has been shown that the conventionally used short-axis (SA) LGE acquisition with anisotropic resolution may overestimate the scar size due to partial volume effect, undermining the prognostic and diagnostic accuracy of LGE MRI in critical clinical applications. In this work, we present a method for combining three complementary anisotropic orthogonal LGE sequences of the heart region into a single isotropic volume. Our algorithm is based on the super-resolution reconstruction technique and employs joint localized gradient-correlation-based technique for compensation of breathing motion. The proposed method was validated on the gold standard electroanatomical voltage mapping (EAVM) data of 15 post-infarction patients. The reconstructed myocardial scar image demonstrated improved agreement with the EAVM compared to the conventional SA image, especially at the clinically significant gray zone region