Bubble Study

Question 1

What are the clinical benefits of a bubble study?

Answer 1

Used to roll out intracardiac right to left shunting and intrapulmonary shunting.

Intracardiac right to left shunting can indicate serious cardiovascular issues, while intrapulmonary shunting involves the presence of bubbles in the left atrium after five seconds.

Question 2

What is the mechanism of a shunt in relation to a PFO?

Answer 2

Typically less bubble seen in a PFO; atrial septal aneurysm shows hyper movement of the fossa ovalis tissue.

A PFO (Patent Foramen Ovale) is a type of shunt that can allow blood to flow between the chambers of the heart inappropriately.

Question 3

What conditions are associated with a PFO?

Answer 3

• Transit ischemic attack (TIA) or cerebrovascular accident (CVA)
• Paradoxical emboli: transient movement of a thrombus across a PFO causing TIA or CVA.

A paradoxical embolism occurs when a blood clot moves from the venous system to the arterial system through a shunt.

Question 4

What equipment is typically used for a bubble study?

Answer 4

• 210 mL saline flush
• 118 gauge needle
• Three-way stopcock.

Question 5

What is the protocol for a bubble study?

Answer 5

• Inject saline with room air, agitated between two syringes
• Acquire for chamber view
• Begin acquiring before bubbles enter the right heart
• Acquire at least 10 beats after contrast appearance.

If bubbles cross in less than five beats, there is a PFO or ASD; if bubbles show up in the left heart greater than five beats, there is an intrapulmonary shunt.

Question 6

What is the typical size of red blood cells?

Answer 6

6 to 8 µm.

Question 7

What is the bubble size of ultrasound enhancing agents (UEA)?

Answer 7

Typically less than 10 µm.

UEA bubbles are small to allow traversal through the pulmonary vascular.

Question 8

What are the indications for imaging with ultrasound enhancing agents?

Answer 8

• Suboptimal image quality
• Roll out masses
• Apical hypertrophy
• Pseudoaneurysms.

Ultrasound enhancing agents help visualize endocardial border definition for tracing ejection fraction percent and enhancing the Doppler signal for the TR jet.

Question 9

What myocardial index is recommended when using contrast?

Answer 9

Less than three.