CTPA Protocols

Computed tomography pulmonary angiography, or CTPA, is a diagnostic test used to evaluate the blood vessels and tissues in a patient's lungs, explains RadiologyInfo.org. One of the primary indications for CTPA testing is a suspected pulmonary embolism, or artery blockage in the lungs, which is a life-threatening medical emergency.

Preparation

• Prior to the start of scanning, the patient will lie down on the scanning table, either on his back, side or stomach. He may require straps to better enable him to hold his position. A nurse or technician will then insert a needle into the patient's vein to inject the contrast material. The most common contrast materials are iodine, barium and barium sulfate.

During the Scan

• The table moves into the scanning area. During the scan, an automatic injection machine will continue to control the flow of the contrast material. In addition to refraining from any unnecessary movement, the patient may be asked to hold his breath for brief intervals to avoid creating false images, or "artifacts," on the scans.

After the Scan

• The scanning process itself takes only seconds, but after it is over, the patient will remain on the examination table while a technologist reviews the scans to ensure that they are clear. Once she has confirmed that the scans are free from artifacts, the IV is removed and the patient may dress and leave the facility.