流量 = PISA * Va
其中:
PISA = 近端等速表面積
Va = 失真流速
壓力梯度 (PGr),單位 mmHG
Oh, J.K., J.B. Seward, and A.J. Tajik. The Echo Manual. 3rd Edition, Philadelphia: Lippincott, Williams, and Wilkins,
(2007), 63-66.
2
PGr = 4 * ( 流速 )
峰值 E 壓力梯度 (E PG)
2
E PG = 4 * PE
峰值 A 壓力梯度 (A PG)
2
A PG = 4 * PA
峰值壓力梯度 (PGmax)
2
PGmax = 4 * PV
平均壓力梯度 (PGmean)
Echocardiographic Assessment of Valve Stenosis: EAE/ASE Recommendations for Clinical Practice Journal of
American Society of Echocardiography, (January, 2009), 4-5.
2
PG mean = sum(4v
)/N
其中:
v = 間隔 n 之峰值流速
N = Riemann 總和中的間隔數量。
壓差減半時間 (PHT),單位 msec
Oh, J.K., J.B. Seward, A.J. Tajik. The Echo Manual. 3rd ed., Philadelphia: Lippincott, Williams, and Wilkins, (2007),
73-74.
PHT = DT * 0.29
其中:
DT = 減速時間
SonoSite Edge II 超音波儀器
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