Detection of pericardial effusion was the earliest clinical application of echocardiography. Diagnosing large effusions is a non issue .Assessing minimal effusions (Systolic vs diastolic echo free space) and associated thickened pericardium is tough even after 50 years of echocardiography.
Mainly , we are limited by the resolution power of echo. Further , lack of echocardiographic landmark for visceral layer of pericardium (It is same as epicardium !) makes diagnosis of thickened pericardium a real tough exercise.It is said , normal pericardium is less than 4mm .
Where to measure it ? how to measure is still not clear.
Why differentiating minimal pericardial effusion from thickened pericardium is important ?
- Mild pericardial effusion is largely a benign finding in vast majority.
- But , even a minimally thickened pericardium due to active inflammation can be significant.
- Sticky pericardial effusion predispose to thickening and constriction.
- Early recognition of this dreaded pericardial pathology is essential to interrupt the inflammatory process.
- In CRF (With or without dialysis) even a minimal pericardial effusion can denote a dismal outcome .
Here is a link to Horowitz classification of mild pericardial effusion ...
http://circ.ahajournals.org/cgi/reprint/50/2/239
It could help us understand, How thickened pericardium presents in echo. Of course, CT and MRI now have increased sensitivity for diagnosing pericardial thickening.
Dr.S.Venkatesan MD 