Sometimes referred to as a Nuclear Stress Test, this diagnostic imaging study is most often used to evaluate blood flow to the heart’s muscle tissue (myocardium), as well as myocardial scarring or infarction (heart attack), in order to diagnose and assess the significance of coronary artery disease (CAD). A myocardial perfusion imaging study might be performed when a traditional exercise stress test fails to produce a clear diagnosis of coronary artery disease. It is also used to assess tissue viability after a heart attack and to verify the results of a bypass operation. Myocardial perfusion imaging may be performed at rest, or more commonly, in conjunction with cardiac stress using exercise or pharmacologic stimulation. A small amount of a gamma-emitting radioisotope is administered intravenously and the patient is placed under a specialized camera. The most common camera is comprised of two detectors that move around the patient to cover 360° and create several images. The advantage of the dual-headed detectors is that only a 180° rotation is necessary, cutting imaging time in half. The images captured by the detectors are reconstructed to produce an image of the heart. A comparison of the images will determine if blood flow is being restricted by a blockage in the coronary artery. See the links below for more information, or to learn about the innovators behind this technology.

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Angiography is commonly used to diagnose coronary artery blockage but is also used to examine the brain, kidneys, lungs, legs and neck. It is useful in identifying brain aneurysms or the cause of internal bleeding or plaque deposits in the carotid artery, which could lead to a stroke. A catheter—a small tube—is inserted into the artery through an incision in the skin and guided to the area being examined. A contrast solution containing iodine is then injected into the bloodstream so that blood vessels appear white in the images produced by the x-rays, allowing doctors to see blood vessels in specific areas of the body. See the links below for more information, or to learn about the innovators behind this technology.

Better known as a CT scan, this medical innovation has proven extremely beneficial in diagnosing conditions related to the head, lungs, pelvis, and heart. CT scans build upon x-ray technology to produce cross-sectional views of an area of the body. Multiple x-rays produce a series of pictures—called slices—that are assembled by a computer to produce a multi-dimensional image that is displayed on a monitor or printed page. A contrast agent containing iodine injected into the bloodstream enhances the images so that blood vessels appear white in the images produced by the x-rays, allowing doctors to see blood vessels and other elements of the circulatory system in specific areas of the body. New multi-slice CT scanners, which take multiple images in a single rotation, have enhanced the value of this technology, with the 64-slice CT scan being especially useful in diagnosing coronary artery disease (CAD). The short 5-13 second scan time and accuracy of the results make the 64-slice CT scan a viable alternative for patients unable to complete a stress test. Multi-slice CT scans have also proven beneficial in detecting tumors of the colon and complications following lung transplants. See the links below for more information, or to learn about the innovators behind this technology.

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Better known as MR imaging, this sectional technique relies on strong magnetic fields and radio waves to produce detailed images of organs, soft tissue, bone and virtually all other internal body structures. This ability to show detailed structures and assess function makes MR an invaluable diagnostic tool. During MR, a narrow tube moves the patient through a tunnel-like structure, radio waves pass through a magnetic field around the patient, and a 3-D image of the internal structures is created. Injectable contrast media is utilized in MR as well as CT, but the reasons for use and how it works is different than in CT. In x-ray and CT it is used to block light from passing through the area being studied. In MR, the contrast works by altering the local magnetic field in the tissue being examined. The image created can then be studied from many different angels on a computer monitor. MR images show differences in water content among various body tissues making MR especially well-suited to detecting disorders that increase fluid in diseased areas of the body, such as those affected by tumors, infection and in-flammation.

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Most people associate ultrasound with pregnancy, but it has a wide variety of uses. Ultrasound uses high-frequency sound waves to examine internal organs—such as the heart, liver, and kidneys—to detect changes in size and function as well as spot tumors. Doppler ultrasound, which examines blood flowing through a blood vessel, can be used to identify clots or narrowing caused by plaque, allowing physicians to identify candidates for angioplasty. A transducer is placed on the body and emits sound waves, which are reflected as echoes that are processed to create an image. Advances in ultrasound technology have enabled the production of three-dimensional images as well as traditional flat images. See the links below for more information, or to learn about the innovators behind this technology.