[Contribution of early systole to total antegrade flow volume in breath-hold phase-contrast flow measurements].
OBJECTIVE
To evaluate the contribution of early systole for the assessment of antegrade aortic flow volume by breath-hold velocity-encoded magnetic resonance (MR) flow measurements.


METHODS
Expiratory breath-hold fast low-angle shot (FLASH) phase-contrast flow measurements (temporal resolution tRes 61 msec, shared phases) perpendicular to the proximal ascending aorta and short axis true fast imaging with steady-state precession (TrueFISP) cine MR ventriculometry (tRes 34.5 msec) were performed in ten healthy male volunteers on a 1.5 T MR system (Sonata, Siemens Medical Solutions). Antegrade aortic flow volume (AFV) and left ventricular stroke volume (LV-SV) were evaluated using Argus Ventricular Function and Argus Flow Software, version MR 2002B (Siemens Medical Solutions). A beta release of Argus Flow MR 2004A allowed interpolation of the flow up-slope during early systole to the preceding R-wave trigger. The respective intraindividual median differences between the AFV of each flow evaluation and LV-SV as well as between both AFV measurements were calculated and compared using the sign test for paired samples.


RESULTS
Non-interpolated AFV significantly deviated from LV-SV (p = 0.006), underestimating the latter by 13.1 mL (13 %). Interpolating aortic flow during early systole significantly increased AFV by 10.8 mL (13 %) compared to the flow evaluation which did not take early systole into account (p = 0.006). AFV with interpolation of early systolic flow agreed well with LV-SV (median difference - 3.0 mL or - 3 %, respectively), and no significant difference between these measurements was found (p = 1.0).


CONCLUSIONS
Flow during early systole contributes substantially to total forward flow volume in the ascending aorta. Interpolation of the early systolic up-slope is therefore recommended for the evaluation of breath-hold phase-contrast flow measurements.
Kunz
R P
RP
Klinik und Poliklinik für Radiologie, Klinikum der Johannes Gutenberg-Universität, Mainz. kunz@radiologie.klinik.uni-mainz.de
Oellig
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Krummenauer
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Oberholzer
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Neeb
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D
Vomweg
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TW
Horstick
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Kreitner
K-F
KF
D000328:Adult; D001011:Aorta / Q000033:anatomy & histology / Q000502:physiology*; D016477:Artifacts; D001783:Blood Flow Velocity / Q000502:physiology; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009068:Movement; D015203:Reproducibility of Results; D012119:Respiration; D012680:Sensitivity and Specificity; D013318:Stroke Volume / Q000502:physiology*; D013599:Systole / Q000502:physiology*; D016277:Ventricular Function, Left / Q000502:physiology*