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Semiquantitative fast flow velocity measurements using catheter coils with a limited sensitivity profile
Author(s) -
Volz Steffen,
Zuehlsdorff Sven,
Umathum Reiner,
Hallscheidt Peter,
Fink Christian,
Semmler Wolfhard,
Bock Michael
Publication year - 2004
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.20170
Subject(s) - signal (programming language) , flow velocity , catheter , blood flow , laminar flow , biomedical engineering , sensitivity (control systems) , flow (mathematics) , flow measurement , materials science , acoustics , nuclear magnetic resonance , physics , mechanics , computer science , radiology , medicine , electronic engineering , engineering , programming language
Flow measurements can be used to quantify blood flow during MR‐guided intravascular interventional procedures. In this study, a fast flow measurement technique is proposed that quantifies flow velocities in the vicinity of a small RF coil attached to an intravascular catheter. Since the small RF coil receives signal from only a limited volume around the catheter, a spatially nonselective signal reception is employed. To enhance signal from flowing blood, and suppress unwanted signal contributions from static material, a slice‐selective RF excitation is used. At a velocity sensitivity of 150 cm/s, a temporal resolution of 2 × TR = 10.2 ms can be achieved. The flow measurement is combined with an automatic slice positioning to facilitate measurements during interventional procedures. The influence of the catheter position in the blood vessel on the velocity measurement was analyzed in simulations. For blood vessels with laminar flow, the simulation showed a systematic deviation between catheter measurement and true flow between −15% and 80%. In four animal experiments, the catheter velocity measurement was compared with results from a conventional ECG‐triggered 2D phase‐contrast (PC) technique. The shapes of the velocity time curves in the abdominal aorta were nearly identical to the conventional measurements. A relative scaling factor of 0.69–1.19 was found between the catheter velocity measurement and the reference measurement, which could be partly explained by the simulation results. Magn Reson Med 52:575–581, 2004. © 2004 Wiley‐Liss, Inc.