Open letter in response to NYT article from July 31, 2010 “The Radiation Boom After Stroke Scans, Patients Face Serious Health Risks” By WALT BOGDANICH
posted by Michael H. Lev and Max Wintermark
Every year in the United States, more than three quarters of a million people have a stroke, and approximately every 3 minutes someone dies from a stroke. A significant portion of stroke victims are young, and left with a devastating handicap for the rest of their lives. The monetary and societal costs of stroke represent a major economic challenge to the healthcare system. With stroke – as with heart attack – rapid treatment is essential to limit the extent of irreversible brain injury (“time-is-brain”), and rapid determination of the cause and degree of existing brain injury can be critical in deciding treatment.
CT perfusion imaging is a quick, widely available test that displays information about blood flow to the brain that can help diagnose, treat, and predict outcome in stroke patients. When MRI is not readily available or contraindicated, CT perfusion imaging provides the best possible estimate of brain tissue likely to die without urgent, advanced therapies, including arterial “clot busting” drugs and blood clot retrieval devices. CT perfusion imaging can also help classify reversible brain injury (“transient ischemic attacks”) that – like cardiac angina – may not require such immediate, aggressive treatment, as well as evaluate brain injury caused by arterial spasm due to bleeding from aneurysm rupture.
Published protocols for performing CT perfusion imaging at “as low a radiation dose as reasonably achievable” – a principle endorsed by the American College of Radiology and American Society of Neuroradiology – have circulated in the medical community for over a decade. Strict protocol rules and oversight radiation protection personnel at most medical centers ensure that optimal image quality is maintained with a total radiation exposure often considerably lower than the current FDA recommended maximum dose. Indeed, in an early, highly quoted study …