MR flow mapping of dobutamine‐induced changes in diastolic heart function

Abstract

Purpose:To evaluate the ability of MR flow mapping to measure changes in left ventricular filling during ␤-adrenergic stimulation. Materials and Methods:Mitral flow was measured in 10 healthy volunteers using conventional free breathing fastfield echo (FFE) with a spatial resolution of 2.7 ϫ 2.2 mm and a temporal resolution of 22 msec. The sequence was repeated during dobutamine infusion (20 g/kg/minute).Results: Stroke volume increased from a median of 99 mL (range: 68 -142 mL) (Note: values as presented are medians and ranges, throughout) to 114 mL (87-180 mL) (P Ͻ 0.05). Both early (E) peak filling rate (554 mL/second [433-497 mL] to 651 mL/second [496 -1096 mL/second]) (P Ͻ 0.05) and atrial (A) peak filling rate (238 mL/second [183-352 mL/second] to 341 mL/second [230 -538 mL/second]) (P Ͻ 0.05) increased. These changes, together with the increase in E acceleration peak and A deceleration peak, were consistent with facilitated myocardial relaxation. Conclusion:Conventional free breathing FFE has the ability to measure the effects of ␤-adrenergic stimulation on left ventricular filling.

Myocardial ischemia in asymptomatic adults with repaired aortic coarctation

“…Excellent data has accumulated over the past several years validating multislice CT coronary angiography for detection of vessel wall disease compared to intracoronary ultrasound. In addition, we used standard inflow and tissue velocity measurements [18,19] that have been well-correlated with echocardiography for measurement of diastolic function compared to invasivelymeasured left ventricular end-diastolic pressures.…”

“…6. Transmitral flow measurements were obtained with a retrospectively electrocardiographically triggered Flash phase-contrast MR technique with a velocity sensitivity of 130 cm/s [18]. Myocardial tissue velocities were measured using this phase-contrast MR sequence with velocity encoding of 30 cm/s [19].…”

Doppler Echocardiography

“…Although CMR is known as the modality of choice for the evaluation of global LV function [20,21], systolic function and myocardial viability [22,23], Doppler echocardiography remains the clinical reference for the evaluationo fd i a s t o l i cd y s f u n c t i o n [4,24,25]. Several CMR studies, based on volume variation curves extracted from cine images [26][27][28][29] or on velocity and flow rate curves extracted from PC images [8][9][10][11][12][13][14][15], reported capabilities of this modality for the assessment of diastolic function. However, despite these methodological developments and the recent technological improvements in PC-CMR sequences, the use of CMR in clinical evaluation of diastolic function remains limited because of the lack of automated methods designed for the analysis of PC images.…”

“…However, despite these methodological developments and the recent technological improvements in PC-CMR sequences, the use of CMR in clinical evaluation of diastolic function remains limited because of the lack of automated methods designed for the analysis of PC images. Indeed, most of the PC-CMR studies previously presented in the literature were based on manual positioning of ROIs on each phase of the cardiac cycle [8][9][10][11][12][13][14][15]. This manual positioning is time-consuming [30] and subjective [8], leading to inter-and intra-operator variability, as reflected by the previously reported variability coefficient of 10% [31].…”

“…Furthermore, several studies demonstrated the usefulness of phase-contrast (PC) CMR in the measurement of some of the aforementioned conventional diastolic parameters [6][7][8]. However, these analyses were mostly based on manual positioning of regions of interest (ROIs) within the transmitral flow area or the myocardium on multiple phases [8][9][10][11][12][13][14][15]. This manual positioning of ROIs is time-consuming and operator-dependent.…”