Echo

Question 1

Speed of sound in tissue

Answer 1

1540 m/s

Question 2

Hemisphere surface

Answer 2

2pir^2

Question 3

PISA (standard way)

Answer 3

1. Regurgitant flow rate (ml/s) = hemisphere area (cm^2) * aliasing velocity/nyquist limit (cm/s)
2. EROA (cm^2) = Regurgitant flow (ml/s) / MR velocity (cm/s)
3. RV (ml) = EROA (cm^2) * VTI (cm)
4. RF % = RV/RV+FSV (Ao)

Question 4

PISA (Oyama)

Answer 4

1. RV (ml) = hemisphere area (cm^2) * aliasing velocity (cm/s) * MR duration

Question 5

EROA

Answer 5

EROA (cm^2) = Regurgitant flow rate (ml/s) / peak velocity (m/s)
EROA (cm^2) = RV / VTI

Question 6

Nyquist limit

Answer 6

1/2 PFR

Question 7

Pressure half-time cutoff for aortic regurgitation

Answer 7

<300 (200) msec = severe

>500 msec = mild

Question 8

Mitral stenosis valve area

Answer 8

MS area = 220/PHT