Intravascular Ultrasound (IVUS)
Transesophageal Echocardiogram (TEE)
A transesophageal echocardiogram or TEE utilizes the insertion of a transducer attached to the tip of a thin tube, or endoscope into the esophagus to visualize the heart, as the esophagus provides optimal viewing. Use of a TEE study provides better and clearer images of the heart and its structures for this reason. TEE can be used as an effective alternative to TTE, if images produced by the TTE are obstructed or unclear due to obesity, bone structure or scarring on the chest wall and certain lung diseases. TEE can be especially useful when evaluating disease of the left upper chamber of the heart (aorta) or valve infection, as these areas are not as clearly visible in a TTE. It is also a useful in detection of abnormal masses inside or outside the heart, identification of clots and causes of strokes and ministrokes, and looking for aortic dissection in a critically ill patient when CT and MRI are not feasible diagnostic options.
Fractional flow reserve (FFR)
Fractional flow reserve (FFR) is defined as the pressure beyond the coronary stenosis relative to the pressure before the stenosis. After cardiac catheterization FFR is measured to determine need for a coronary intervention when blockages may appear to be borderline severe on angiogram.