Second, CT scans provide valuable information about the stone that is simply not possible to obtain with US, which can guide management options and optimize therapy for the patient. Some of the characteristics that are lacking with US measurement include stone size, location, and density, how far the stone is from the skin, and the exact anatomical relationship with the GU system. This can guide therapy in a number of ways. For example, the Hounsfield Unit reading in a CT scan can determine density of the stone and the likelihood of success using shockwave lithotripsy for treatment. Additionally, as opposed to US, a CT scan can accurately determine whether or not a stone is impacted based on the Hounsfield Unit measurement from the scan. This can help a surgeon decide if they should pre-stent the patient, hold anti-platelet agents, or pre-treat with alpha blockers before definitive management. The Hounsfield Unit readings can also be used to look at bone mineral density in the vertebral bodies and this can be especially helpful for determining in the patient has osteopenia or osteoporosis.
Finally, Dr. Monga advocates for the use of CT’s by dispelling the fear of radiation risks associated with this imaging modality. Data presented show that the absolute increase in lifetime cancer risk from a CT scan is only .02% per scan. He also offers alternatives to the standard radiation dose, such as through low dose CT scans, which provides similarly high sensitivity for diagnosing stones, and iterative reconstruction technology, which provides a high quality image with a lower dose of radiation. In sum Dr. Monga re-emphasizes that CT scans, when used appropriately, do not meaningfully increase one’s radiation risk and are necessary for guiding management strategies.
Presented by: Manoj Monga, Head of the Endourology Unit, Cleveland Clinic Foundation
Written by: Max Towe, medical writer for UroToday.com at the 36th World Congress of Endourology (WCE) and SWL - September 20-23, 2018 Paris, France
Read: Radiations Risk: Much Ado about Nothing? – Radiationless Surgery