Fluid in the subcostal cardiac view
What does this subcostal view show? In a twitter poll, more than 50% thought its either pericardial effusion or a pericardial tumor. The correct answer is ascites.
Subcostal view of the heart is relatively easy to obtain in most patients and is commonly used to exclude pericardial effusion on focused exams. Therefore, it is important to know how ascites and pleural effusion (previously discussed) appear in this window to avoid misdiagnosis. Ascites appears anterior to the right cardiac chambers. In these cases, the falciform ligament and liver appear floating in the anechoic fluid. Moreover, extending the examination to the rest of the abdomen will easily demonstrate the presence of ascites and confirm the diagnosis when in doubt. Below is the labeled image.
Below is an excellent image demonstrating ascites, trace pericardial effusion (seen only during systole) and left pleural effusion (note collapsed lung) visualized in subcostal window.
Here is an image showing ascites and right pleural effusion.