A nuclear stress test is an imaging procedure used to evaluate how blood flows to the heart muscle both at rest and during physical stress, often induced by exercise or medication. The test involves injecting a small amount of a radioactive tracer into the bloodstream, which is then detected by a special camera to create pictures of the heart. Careful preparation, starting with selecting the right attire, is required for accurate results and patient safety. The clothing chosen directly impacts the technical success of the imaging and safety during physical exertion.
Choosing Clothing for Comfort and Movement
The stress component typically involves walking on a treadmill or riding a stationary bike to increase heart rate and blood flow. Therefore, clothing should prioritize comfort and ease of movement, similar to moderate workout attire. Loose-fitting, two-piece clothing is recommended, such as athletic shorts or sweatpants paired with a t-shirt or short-sleeved top. Breathable fabrics like cotton or moisture-wicking synthetics are best to manage perspiration during physical activity.
Wearing layers is practical, as the imaging room where the gamma camera is located may be cooler than the exercise area. Technicians need unobstructed access to the chest and arms to place EKG leads directly onto the skin and frequently use a blood pressure cuff. A short-sleeved shirt is ideal for easy placement of the intravenous (IV) line used to administer the radioactive tracer and for blood pressure monitoring.
Mandatory Metal and Accessory Restrictions
The most crucial preparation relates to the imaging portion of the test, where metal objects must be completely avoided. A specialized gamma camera detects the radioactive tracer in the heart to create detailed images. Any metal positioned over the chest or near the camera’s field of view interferes with tracer detection and creates image artifacts, appearing as shadows or distortions. These artifacts can obscure the heart, making it difficult for the cardiologist to accurately interpret blood flow patterns, potentially leading to inconclusive results.
To prevent this interference, patients must avoid all clothing and accessories that contain metal, especially near the chest or torso. This includes underwire bras, shirts or pants with metal zippers, metal snaps, or large belt buckles. Accessories such as watches, necklaces, metal hair clips, and body piercings must be removed before the test begins. It is best to wear simple, non-metallic undergarments and outerwear, as even coins or keys left in pockets can cause issues.
Essential Footwear Requirements
The footwear chosen is directly linked to patient safety during the physical stress portion of the test. To ensure stability and prevent falls on the treadmill, patients must wear closed-toe athletic shoes, such as sneakers or running shoes. These shoes provide the necessary support and traction required for walking or jogging at increasing speeds and inclines.
Footwear that is open-toed, backless, or lacks support should be avoided. This includes sandals, flip-flops, high heels, and dress shoes, which pose a tripping hazard or fail to protect the foot during exercise. Comfortable, rubber-soled walking shoes are essential preparation for a safe and successful exercise segment.
Final Preparation Checklist (Non-Clothing Items)
Beyond clothing, several non-attire preparations are necessary to ensure the physiological accuracy of the test results. Patients are typically required to fast for four to six hours before the procedure, consuming only water. Fasting ensures the radioactive tracer distributes correctly and prevents interference during the imaging process.
A primary restriction is the avoidance of all caffeine for 12 to 24 hours prior to the test. Caffeine, found in coffee, tea, soda, chocolate, and some decaffeinated products, can interfere with pharmacological stress agents used to simulate exercise. Patients must also consult with their physician about which prescription medications to hold. Drugs like beta-blockers or calcium channel blockers can lower the heart rate and mask the true extent of coronary artery disease. Bring an updated list of all medications and supplements, as well as an insurance card, to the appointment.