ULTRASOUND OF PERICARDIAL EFFUSION
  1. Normal Pericardium:
    A thin rim of pericardial fluid (<2 mm) is normal and of no clinical significance. It is visualized as an echo-free rim along the ventricles and atrioventricular groove on either gray scale images or on M-mode echocardiography.
  2. Normal Variant:
    Using older equipment an acoustic "dropout" zone was confused with increased pericardial fluid.
  3. Gray scale imaging -
    Pericardial fluid = an echo free separation of the epicardium from the myocardium by ³2 mm.

 

·         M-mode doppler imaging –

 

·         Color doppler imaging - DeVore and Horenstein (2) demonstrated that pericardial fluid can be detected on color doppler, and that color doppler signals in the pericardial space were opposite in direction to the color doppler signals within the ventricles. This phasic movement of the pericardial fluid is secondary to the phasic changes in the dimension of the pericardial space.

1.      During ventricular systole – pericardial space around the ventricles expand and pericardial fluid moves into this space.

2.      During ventricular diastole – pericardial space disappears as the ventricles expand resulting in the fluid moving out of this space.

3.      The spectral waveform from the pericardial fluid consists of biphasic diastolic flow and monophasic systolic flow (3).

 

 

 

 

 

Video clip of Pericardial Effusion on color doppler imaging

 

 

REFERENCES
  1. Jeanty P, Romero R, Hobbins JC. Fetal pericardial fluid: A normal finding of the second half of gestation. Am J Obstet Gynecol 1984;149:529.
  2. DeVore GR, Horenstein J. Color doppler identification of pericardial effusion in the fetus. Ultrasound Obstet Gynecol 1994;4:1150120.
  3. Yoo S –J, Min J –Y, Lee Y –H. Normal pericardial fluid in the fetus: color and spectral doppler analysis. Ultrasound Obstet Gynecol 2001;18:248-252.