[Flow quantification of intracardiac shunt volumes using MR phase contrast technique in the breath holding phase].
OBJECTIVE
Comparison of a breath-hold, velocity-encoded, phase-difference magnetic resonance (MR) sequence for intracardiac shunt flow measurement with the invasive shunt size determination by oximetry.


METHODS
10 patients with different cardiac shunts (6 ASD/3 VSD/1 PDA) and four healthy individuals were investigated using a 1.5 Tesla Siemens Vision system. For flow measurements a breath-hold, velocity-encoded, phase-difference magnetic resonance (MR) sequence was used ('through plane', FLASH 2D-sequence, TR/TE 110/5 ms, 'velocity encoding' 250 cm/s). Mean flow (ml/R-R interval) in the ascending aorta, the pulmonary trunk, and the right and left pulmonary arteries was determined. The ratio of the mean flow in the pulmonary circulation (Qp: sum of the mean flows in the right and left pulmonary arteries) and the systemic circulation (Qs: mean flow in the proximal aorta) was compared with the Qp/Qs ratios determined by the invasive oxymetric technique. Oximetry was performed within 24 hours after MR imaging.


RESULTS
In the 4 healthy individuals MR flow measurement yielded a Qp/Qs ratio of 0.96 +/- 0.15. In the 10 patients with the various shunt defects, the non-invasive shunt determination by MR gave a Qp/Qs ratio of 2.09 +/- 0.67. The percentage of the calculated shunt sizes was 47.05 +/- 17.45%. In the comparison with the results determined by the invasive oxymetric technique, the MR data showed a strong correlation of r = 0.87.


CONCLUSIONS
Breath-hold, velocity-encoded, phase-difference MR-technique enables a reliable quantification of cardiac shunts within a short acquisition time.
Kalden
P
P
Klinik und Poliklinik für Radiologie, Johannes-Gutenberg-Universität Mainz. kalden@radiologie.klinik.uni-mainz.de
Kreitner
K F
KF
Voigtländer
T
T
Roberts
H
H
Roberts
T
T
Krummenauer
F
F
Becker
D
D
Wittlinger
T
T
Meyer
J
J
Thelen
M
M
D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity / Q000502:physiology; D004374:Ductus Arteriosus, Patent / Q000175:diagnosis* / Q000503:physiopathology; D004867:Equipment Design; D005260:Female; D006344:Heart Septal Defects, Atrial / Q000175:diagnosis* / Q000503:physiopathology; D006345:Heart Septal Defects, Ventricular / Q000175:diagnosis* / Q000503:physiopathology; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D008297:Male; D008875:Middle Aged; D010092:Oximetry / Q000295:instrumentation; D011652:Pulmonary Circulation / Q000502:physiology; D012680:Sensitivity and Specificity
Flussquantifizierung von intrakardialen Shuntvolumina unter Verwendung der MR-Phasenkontrast-Technik in Atemanhaltephase.