This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiac and Pericardiac Imaging, Subject name: Radiology
Plethoric non collapsible IVC on echocardiography denotes? 
Select and explain. 
A. Budd chiari syndrome, B. Hepatic venous malformation, C. Right heart failure, D. IVC thrombosis
C: Right heart failure
Answer: C: Right heart failure 
Explanation: Ans CIn Heart failure increasing IVC diameter is associated with a worse prognosis Q. The IVC diameter is a summary measure of cardiac function as well as a marker of venous congestion. Measurements of IVC collapse are commonly reported as the "collapsibility index" Q which is calculated as (maximum) IVC diameter on expiration - minimum IVC diameter on inspiration/maximum IVC diameter on expiration). Mean IVC diameter correlates with CVPQ.