Original Research MR Flow Mapping of Dobutamine-Induced Changes in Diastolic Heart Function Bernard P. Paelinck, MD, 1 * Hildo J. Lamb, PhD, 2 Jeroen J. Bax, MD, PhD, 3 Ernst E. van der Wall, MD, PhD, 3 and Albert de Roos, MD, PhD 2 Purpose: To evaluate the ability of MR flow mapping to measure changes in left ventricular filling during -adren- ergic stimulation. Materials and Methods: Mitral flow was measured in 10 healthy volunteers using conventional free breathing fast- field echo (FFE) with a spatial resolution of 2.7  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  0.05). Both early (E) peak filling rate (554 mL/second [433– 497 mL] to 651 mL/second [496 –1096 mL/second]) (P  0.05) and atrial (A) peak filling rate (238 mL/second [183–352 mL/second] to 341 mL/second [230 –538 mL/second]) (P  0.05) increased. These changes, together with the increase in E acceleration peak and A deceleration peak, were con- sistent with facilitated myocardial relaxation. Conclusion: Conventional free breathing FFE has the abil- ity to measure the effects of -adrenergic stimulation on left ventricular filling. Key words: magnetic resonance; diastolic function; flow; dobutamine; heart J. Magn. Reson. Imaging 2004;19:176 –181. © 2004 Wiley-Liss, Inc. STRESS TESTING using the synthetic catecholamine dobutamine has become an established method for the diagnosis of coronary artery disease (1). Recently, do- butamine stress MR imaging has been proposed as an alternative for dobutamine stress echocardiography, yielding better test reproducibility and visualization of wall motion abnormalities with high spatial and tempo- ral resolution independent of echogenicity (2). Diastolic function has been widely assessed using pulsed-wave Doppler echocardiography of transmitral flow. The mi- tral flow pattern represents the transmitral pressure gradient and is characterized by a rapid early (E) ven- tricular filling wave due to suction and a late atrial (A) ventricular filling wave due to atrial contraction. The transmitral pressure gradient depends on different de- grees of elastic recoil, chamber compliance, myocardial relaxation and left atrial pressures (3,4). Changes in mitral flow pattern reflect different states of cardiac disease. Experimental and clinical data have shown myocardial ischemia results in a cascade of events with changes in diastolic function preceding contractile dys- function. Therefore, changes in diastolic parameters are more sensitive and early markers of myocardial ischemia (5,6). However, since stress studies have been focused on systolic wall motion and thickening, studies of diastolic function during dobutamine stimulation have been limited. In the healthy heart -adrenergic stimulation improves left ventricular contraction (ino- tropic effect) and accelerates left ventricular relaxation (lusitropic effect) (7–9). Doppler echocardiography has shown these effects on both systolic and diastolic func- tion parameters (10 –14). Phase-contrast MR imaging has been used to measure transmitral blood flow (15– 17). The accuracy of this technique has been studied in experiments in vitro by means of flow phantoms and comparisons with other techniques such as Doppler echocardiography (16 –19). Usually these phase-con- trast MR techniques have not been respiratory compen- sated. Recently, phase-contrast MR techniques using a segmented acquisition in which the excitations are ac- quired in rapid succession (fast echo-planar imaging [EPI] and turbo-field echo-planar imaging) have been introduced allowing single breath-hold acquisition (20,21). We hypothesized that MR flow mapping could mea- sure the effects of dobutamine infusion on left ventric- ular filling. For this purpose we used the well-validated conventional free breathing nonsegmented phase-con- trast MR technique (fast-field echo [FFE]) (22). MATERIALS AND METHODS The study group consisted of 10 healthy volunteers (five men and five women, mean ages 25.3  2 years). After 1 University Hospital Antwerp, Antwerp, Belgium. 2 Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands. 3 Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands. *Address reprint requests to: B.P.P., Department of Cardiology, Univer- sity Hospital Antwerp, Wilrijkstraat 10, 2650 Edegem, Belgium. E-mail: Bernard.paelinck@uza.be Received March 21, 2003; Accepted October 16, 2003. DOI 10.1002/jmri.10448 Published online in Wiley InterScience (www.interscience.wiley.com). JOURNAL OF MAGNETIC RESONANCE IMAGING 19:176 –181 (2004) © 2004 Wiley-Liss, Inc. 176