Limit Computed Tomography (CT) Scanning in Suspected Renal Colic (Prospective)

Computed tomography (CT) scanning is overused, expensive, and causes cancer. CT scan utilization in the U.S. has increased from an estimated 3 million CTs in 1980 to 62 million per year in 2007. From 2000 through 2006, Medicare spending on imaging more than doubled to $13.8 billion with advanced imaging such as CT scanning largely responsible. CT represents only 11% of radiologic examinations but is responsible for two-thirds of the ionizing radiation associated with medical imaging in the U.S. Recent estimates suggest that there will be 12.5 cancer deaths for every 10,000 CT scans. Renal colic is a common, non-life-threatening condition for which CT is overused. As many as 12% of people will have a kidney stone in their lifetime, and more than one million per year will present to the emergency department (ED). CT is now a first line test for renal colic, and is very accurate. However, 98% of kidney stones 5mm or smaller will pass spontaneously, and CT rarely alters management. A decision rule is needed to determine which patients with suspected renal colic require CT. While the signs and symptoms of renal colic have been shown to be predictable, no rule has yet been rigorously derived or validated to guide CT imaging in renal colic. A subset of patients with suspected renal colic may have a more serious diagnosis or a kidney stone that will require intervention; however the investigators maintain that clinical criteria, point of care ultrasound and plain radiography (when appropriate), will provide a more comparatively effective and safer approach by appropriately limiting imaging.