[Dynamic cartography of flow patterns by cine-MRI. Presentation of the technique and preliminary results for major vessels].
The authors report the principles, experimental evaluation and clinical approach of a method for dynamic imaging of flow patterns by NMRI, based upon the phase modulation technique. The imaging method is based upon gradient echo, functioning in "cine" and "flow compensated" mode. Modifications in this sequence enable attribution to the moving spins phase of a value which is considered to be proportional to the flow rate. A map of rates is then obtained from the phase image. Calibration of this sequence in vitro has shown excellent correlations between flow rate and the phase information thus obtained: r always > 0.98 for rates up to m/s. The first results obtained in vivo for the thoracic and abdominal aorta, in 11 control subjects, show that the technique is suitable for the study of pulsatile blood flow, providing very detailed information concerning the spatial distribution of flow rates. Mean flow in the suprarenal abdominal aorta (4.6 +/- 1.6 l/min) is 32% greater than that in the inferior vena cava (3.1 +/- 1 l/min), corresponding to an estimation of portal vein flow of 1.5 l/min. Practical limitations related to the use of a resistive magnet are nevertheless stressed and the authors list the technical aspects necessary for the better clinical utilisation of this non-invasive flowmetric technique. A review of the current literature forms the basis for an assessment of the potential importance of dynamic and quantitative NMRI of flow patterns in the cardiovascular area.
Service de Cardiologie, Hôpital de Hautepierre, CHU, Strasbourg.
P
P
Germain
J
J
Baruthio
D
D
Wecker
G
G
Roul
A
A
Koegler
J M
JM
Mossard
P
P
Bareiss
J
J
Chambron
A
A
Sacrez
D001011:Aorta / Q000502:physiology; D001783:Blood Flow Velocity; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D014682:Vena Cava, Inferior / Q000502:physiology
Cartographie dynamique des flux par ciné-IRM. Présentation de la technique et résultats préliminaires sur les gros vaisseaux.