Use of CT scans in hospital emergency rooms has risen 16% a year since 1995, raising questions about unnecessary radiation exposure and how healthcare costs can be contained against such fervent use of technology.
In a study released Monday in the journal Radiology, researchers found use of CT — computed tomography — procedures increased from 2.7 million nationwide in 1995 to 16.2 million in 2007. The study joins several recent reports showing that the use of sophisticated imaging technology, and the cost associated with it, has grown rapidly.
Meanwhile, little research has been done to show if increased CT scanning, which uses a focused beam of X-rays to provide a well-defined, cross-section view of soft tissues, has benefited patients.
"For people with serious illness, the risk of having a CT exam is outweighed by the benefits," said Dr. David Larson, lead author of the study and a radiologist at Cincinnati Children's Hospital Medical Center. The hard part, he said, is when it's not clear whether the exam will help. "In the past that wasn't such an issue because CT wasn't as available as it is now and it wasn't as good as it is now. But it's increasing on both fronts."
The technology was originally used on trauma patients or to diagnose the cause of headaches and seizures. Today, most hospitals, even in rural areas, have a CT scanner. At a cost of about $400 per body part scanned, it is now a tool for a wide variety of diagnoses.
"In 2001, using it for chest pain was uncommon. Now it's the third most common reason for undergoing a CT in an emergency department," said Larson, who presented the findings in Chicago on Monday at the annual meeting of the Radiological Society of North America.
The study, based on the National Hospital Ambulatory Medical Care Survey — an annual sample of more than 30,000 emergency room visits — found that the top two reasons for ordering a CT in emergency rooms were for abdominal pain and headaches.
The expanding use of CT scans is appropriate in many cases, other radiologists said. They spare doctors from having to guess at a diagnosis and supplant inferior technology, such as using traditional X-rays to look for a kidney stone or a pulmonary angiogram to look for a blood clot in the lungs.
"People have kind of figured out where it's very helpful," said Dr. Elliot Fishman, a professor of radiology and oncology at Johns Hopkins University School of Medicine. The top three applications for CT identified "are applications [for which], over time, CT has been recognized as the exam of choice."
The study also found that CT use was greater in older patients and those later admitted to the hospital, Fishman said. "Those were sicker patients," he said. "If they were admitted to the hospital, there was probably a good reason to do" the scan.
But Larson said more research was needed to verify that CT scans improved patient outcomes. Health insurance companies may force the issue. Insurers increasingly are insisting on approving nonemergency or outpatient CT requests.
Overuse is a concern not just because of cost but because of radiation exposure. Recent studies suggest that patients may be harmed by the overuse of medical imaging technology. In a 2006 report, the National Research Council found that 1 in every 1,000 people who got 10 millisieverts of radiation would develop cancer. A single CT scan of the head, cervical spine, chest, abdomen and pelvis adds up to 37 millisieverts, the report said.
"Patients should understand the risk is low," Larson said. "If the patient or a loved one is very sick with a life-threatening illness or cancer, they really shouldn't be concerned about radiation.
"Otherwise, it's worth having a conversation with the doctor to see if there are alternatives to CT."