FujiFilm SonoSite SII, User Manual Supplement

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38 Measurement references
Pressure Gradient (PGr) in mmHG
Oh, J.K., J.B. Seward, A.J. Tajik. The Echo Manual . 2nd ed., Philadelphia: Lippincott, Williams, and Wilkins,
(1999), p.64.
PGr = 4 * (Velocity)
2
Peak E Pressure Gradient (E PG)
E PG = 4 * PE
2
Peak A Pressure Gradient (A PG)
A PG = 4 * PA
2
Peak Pressure Gradient (PGmax)
PGmax = 4 * VMax
2
Mean Pressure Gradient (PGmean)
PGmean = Average pressure gradient during the flow period
Baumgartner, H., Hung, J., Bermejo, J., et al. “Echocardiographic Assessment of Valve Stenosis: EAE/ASE
Recommendations for Clinical Practice”.
Journal of American Society of Echocardiography . January 2009, p.
4-5.
PG mean = sum(4v
2
)/N
where: v =peak velocity at interval n
N = the number of intervals in the Riemann sum
Pressure Half Time (PHT) in msec
Reynolds, Terry, The Echocardiographer’s Pocket Reference , 2nd Edition, School of Cardiac Ultrasound,
Arizona Heart Institute, (2000), p. 391.
PHT = DT * 0.29 (time required for the pressure gradient to fall half its maximum level)
where: DT = deceleration time
Proximal Isovelocity Surface Area (PISA) in cm
2
Oh, J.K., J.B. Seward, A.J. Tajik. The Echo Manual . 3rd ed., Philadelphia: Lippincott, Williams, and Wilkins,
(2007), p.74-76.
PISA = 2 π r
2
where: r = aliasing radius