- A BART scan of the forearm. The brachial artery vascular reactivity test (BART) is designed to look at the function of the endothelium (the blood vessel lining) using high-resolution ultrasound. This is a non-invasive test. The test is performed with the subject lying down. A blood pressure cuff is placed on the right forearm, just below the bend in the elbow. This cuff is attached to an automatic cuff inflator. The sonographer will hold an ultrasound transducer over the subject's left arm artery (brachial), their upper arm, and measure the size and the blood flow in the artery at baseline. Then the sonographer will inflate a blood pressure cuff over the lower arm for about 5 minutes. After the cuff is released the sonographer will take a picture of the size and blood flow in the artery for 2 minutes after the cuff is released. This test measures the ability of the brachial artery to get bigger (dilate) when exposed to increased blood flow; this ability is a measure of the health of the blood vessel lining. This test may cause temporary numbness and tingling.