What used to be invisible in artery walls can no longer hide with technology now being used by cardiologists at McLaren Regional Medical Center. Since January, these heart care specialists have been using a new diagnostic tool to literally see the anatomy of patients' arteries from inside the body. McLaren was the first hospital in Michigan to use Optical Coherence Tomography (OCT), manufactured by St. Jude Medical, it is a leading imaging technology that aids physicians in the diagnosis and treatment of cardiovascular disease during cardiac catheterization. You may be familiar with this common procedure in which a long, thin, flexible tube called a catheter is put into a blood vessel in the groin, arm or neck and threaded through the body to the heart. It is most often done to evaluate chest pain.
Optical Coherence Tomography is also catheter guided, and is made up of a camera and light system that is also inserted into the body through a blood vessel. The system uses near-infrared light to create high-resolution images that allow physicians to visualize and measure important vessel characteristics otherwise invisible or difficult to assess with other imaging technology. Currently, fluoroscopy is the standard imaging technology used in catheterization labs. During a fluoroscopy procedure, an x-ray beam is passed through the body. The image is transmitted to a monitor so that the body part and its motion can be seen in detail. The detail is provided by a contrast die injected by coronary angiography, a very small tube (catheter) also inserted through the groin, arm, or neck to the heart, or the arteries supplying blood to the heart, where the die is then released for viewing via the x-ray.
"As useful as fluoroscopy and angiography are for most cases, they cannot provide the anatomical detail that OCT can," states Dr. Jeffrey Harris, interventional cardiologist and Medical Director of McLaren's Cath Lab. "When something we are looking at through fluoroscopy is questionable we can now use OCT to actually see anything of concern, whether it be the true density of a blockage, any anatomical defects or complex anatomy, or even hidden blood clots. This affords the cardiologist better placement of stents, optimizing treatment during the catheterization and in planning future treatment."
The superior quality comes from the imaging being 10 times greater than fluoroscopy and intravascular ultrasound (IVUS) which uses high frequency sound waves to produce an image from inside the arteries. In comparison fluoroscopy provides a two-dimensional image, IVUS shows a cross sectional image versus OCT which is three-dimensional and enhanced as mentioned above. Not only does OCT assist physicians in determining stent placement but it is also beneficial in selecting stent size by providing precise measurements of lesion dimensions and vessel size and structure.
"OCT is an example of how advancements in technology can really show us what is going on in the arteries by allowing us a level of visualization that shows the true differentiation in a person's coronary anatomy," says Dr. Harris. "This will result in good outcomes becoming even better for patients."