What is balloon diameter measured in?

The correct answer relates to the standard practice in interventional radiology and vascular intervention. Balloon diameter is typically measured in millimeters when the balloon is inflated to its nominal pressure. This measurement represents the diameter at which the balloon is designed to function optimally, ensuring that it effectively dilates the vessel or site of interest without exceeding appropriate limits that could cause injury to surrounding tissues.

The measurement in millimeters provides a precise understanding of the size of the balloon at a specific pressure, which is crucial in planning interventions. Clinicians rely on this accurate measurement to choose the appropriate balloon size to match the diameter of the vessel to be treated, ensuring efficacy and safety during procedures.

Other options do not align with standard practice in this context: centimeters may be used in some reports but are less common for balloon measurement; inches are not a standard measurement for medical devices like balloons; and liters are unrelated to the sizing of balloons, as they pertain to capacity rather than diameter.