Sequence optimization to reduce velocity offsets in cardiovascular magnetic resonance volume flow quantification -- A multi-vendor study

Rolf, Marijn P.; Hofman, Mark B. M.; Gatehouse, Peter D.; Markenroth-Bloch, Karin; Heymans, Martijn W.; Ebbers, Tino; Graves, Martin J.; Totman, John J.; Werner, Beat; van Rossum, Albert C.; Kilner, Philip J.; Heethaar, Rob M.
January 2011
Journal of Cardiovascular Magnetic Resonance (BioMed Central);2011, Vol. 13 Issue 1, p18
Academic Journal
Purpose: Eddy current induced velocity offsets are of concern for accuracy in cardiovascular magnetic resonance (CMR) volume flow quantification. However, currently known theoretical aspects of eddy current behavior have not led to effective guidelines for the optimization of flow quantification sequences. This study is aimed at identifying correlations between protocol parameters and the resulting velocity error in clinical CMR flow measurements in a multi-vendor study. Methods: Nine 1.5T scanners of three different types/vendors were studied. Measurements were performed on a large stationary phantom. Starting from a clinical breath-hold flow protocol, several protocol parameters were varied. Acquisitions were made in three clinically relevant orientations. Additionally, a time delay between the bipolar gradient and read-out, asymmetric versus symmetric velocity encoding, and gradient amplitude and slew rate were studied in adapted sequences as exploratory measurements beyond the protocol. Image analysis determined the worst-case offset for a typical great-vessel flow measurement. Results: The results showed a great variation in offset behavior among scanners (standard deviation among samples of 0.3, 0.4, and 0.9 cm/s for the three different scanner types), even for small changes in the protocol. Considering the absolute values, none of the tested protocol settings consistently reduced the velocity offsets below the critical level of 0.6 cm/s neither for all three orientations nor for all three scanner types. Using multilevel linear model analysis, oblique aortic and pulmonary slices showed systematic higher offsets than the transverse aortic slices (oblique aortic 0.6 cm/s, and pulmonary 1.8 cm/s higher than transverse aortic). The exploratory measurements beyond the protocol yielded some new leads for further sequence development towards reduction of velocity offsets; however those protocols were not always compatible with the time-constraints of breath-hold imaging and flow-related artefacts. Conclusions: This study showed that with current systems there was no generic protocol which resulted into acceptable flow offset values. Protocol optimization would have to be performed on a per scanner and per protocol basis. Proper optimization might make accurate (transverse) aortic flow quantification possible for most scanners. Pulmonary flow quantification would still need further (offline) correction.


Related Articles

  • Modelling the bioelectric behaviour of halo pin-patient structures during magnetic resonance imaging. Saari, A.; Runciman, R. J.; Hayward, G. // Proceedings of the Institution of Mechanical Engineers -- Part H;May2004, Vol. 218 Issue 3, p159 

    Bioelectric compatibility of electrically conductive halo fixation devices and magnetic resonance (MR) imaging has been largely based on resulting image quality. Previous studies have focused primarily on improving image quality and, although the electrical characteristics of the system during...

  • Electromagnetic Imaging Using Probe Arrays. Mook, Gerhard; Michel, Fritz; Simonin, Jouri // Strojniski Vestnik / Journal of Mechanical Engineering;Mar2011, Vol. 57 Issue 3, p227 

    Electromagnetic methods like eddy current technique do not provide images but merely produce local signals in a difficult-to- understand measurement plane. Trials to generate images comparable to x-rays are mostly based on costly and time consuming mechanical surface scanning. The paper presents...

  • LABORATORY POD DATA ACQUISITION FROM INNER LAYER CRACKS IN SIMULATED AIRFRAME STRUCTURES. Larson, Brian; Madison, Erin; Nakagawa, Norio // AIP Conference Proceedings;3/3/2009, Vol. 1096 Issue 1, p1840 

    This paper discusses the acquisition and processing of experimental data collected using a low frequency eddy current sliding probe to inspect aluminum, simulated airframe structure for inner layer cracks. This effort is part of a model-assisted probability of detection (MAPOD) study aimed at...

  • Considerations for Using Phased Array Ultrasonics in a Fully Automated Inspection System. Kramb, V. A.; Olding, R. B.; Sebastian, J. R.; Hoppe, W. C.; Petricola, D. L.; Hoeffel, J. D.; Gasper, D. A.; Stubbs, D. A. // AIP Conference Proceedings;2004, Vol. 700 Issue 1, p817 

    The University of Dayton Research Institute (UDRI) under contract by the US Air Force has designed and constructed a fully automated ultrasonic inspection system for the detection of embedded defects in rotating gas turbine engine components. The system performs automated inspections using the...

  • A Database Design for the Storage and Statistical Analysis of Impedance Data for the Characterization of Noise In Eddy-Current Scans. Nelson, D. L.; Johnson, M. J.; Nakagawa, N. // AIP Conference Proceedings;2004, Vol. 700 Issue 1, p613 

    This database design is associated with a research program aiming at characterizing eddy-current noise sources by scanning approximately thirty Inconel and titanium-alloy flat-plate specimens. By nature, such a project generates a large amount of data, as any one specimen may be scanned with...

  • Eddy-Current Testing with GMR Magnetic Sensor Arrays. Smith, C. H.; Schneider, R. W.; Dogaru, T.; Smith, S. T. // AIP Conference Proceedings;2004, Vol. 700 Issue 1, p406 

    The advent of GMR magnetic sensors and GMR sensor arrays with frequency-independent sensitivity offers improvements in speed, depth, and resolution in eddy-current testing. Arrays of GMR magnetic sensors allow rapid scanning of an area for defects in a single pass. The small size and low power...

  • Metallurgical and Technological Request for High Purity Niobium in SRF Application. Singer, W. // AIP Conference Proceedings;2006, Vol. 837 Issue 1, p51 

    Properties of niobium are analyzed regarding application in superconducting radio frequency accelerator systems. High purity niobium should meet the tough specification. Interstitially dissolved impurities like oxygen, nitrogen and carbon should be kept under few wt. ppm. Hydrogen can under...

  • A Novel Multi-Frequency Eddy Current Measurement Technique for Materials Characterization. Ko, Ray T.; Blodgett, Mark P.; Sathish, Shamachary; Boehnlein, Thomas R. // AIP Conference Proceedings;2006, Vol. 820 Issue 1, p415 

    In an effort to meet the needs for high frequency eddy current measurements and be able to distinguish small conductivity variations in different materials, a new eddy current module capable of measuring magnitude, phase, and frequency shift was developed and integrated into a general-purpose...

  • 2015 WFNDEC Eddy Current Benchmark Modeling of Impedance Variation in Coil Due to a Crack Located at the Plate Edge. Rocha, João Vicente; Camerini, Cesar; Pereira, Gabriela // AIP Conference Proceedings;2016, Vol. 1706 Issue 1, p1 

    The 2015 World Federation of NDE Centers (WFNDEC) eddy current benchmark problem involves the inspection of two EDM notches placed at the edge of a conducting plate with a pancake coil that runs parallel to the plate's edge line. Experimental data consists of impedance variation measured with a...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics