An abdominal CT scan, which uses X-rays to create cross-sectional pictures of the belly area, is the most common imaging test used for confirming a patient has the condition. Many believe CT scans' higher sensitivity and detailed imaging leads to more rapid diagnosis and cuts the time a patient spends in the emergency department. However, unlike an ultrasound, the test exposes patients to ionizing radiation, which may increase a patient's lifetime risk of developing cancer, according to the FDA.
Researchers investigated whether increased CT use was associated with improved patient outcomes. They looked at a total of 2,759 patients who visited one of 15 geographically diverse academic emergency departments between October 2011 and February 2013, and were randomly assigned by either an ED physician or radiologist to undergo ultrasonography or abdominal CT scan. The physician could order additional imaging later if clinically indicated for the patient.
“Patients in the ultrasonography groups were exposed to a lower total amount of radiation than were patients in the CT group, with no significant difference in high-risk diagnoses with complications, total serious adverse events or related serious adverse events,” the authors concluded. Pain scores, hospital admissions and emergency department readmissions also did not differ significantly between the two groups, the study found.
It's not that a patient should never have CT scans, the authors say, “but rather that ultrasonography should be used as the initial diagnostic imaging test, with further imaging studies performed at the discretion of the physician on the basis of clinical judgment.” The findings were published Wednesday in the New England Journal of Medicine.
In an accompanying editorial, Harvard professor Dr. Gary Curhan agreed, but noted there are pros and cons for each test. The decision to use ultrasound should be balanced against the additional information obtained by a CT, he said, and no matter which method is chosen, it's important to reinforce prevention strategies with patients.
Others have drawn similar conclusions about use of CT scans for detecting kidney stones in the ED.
Research presented in May at the annual meeting of the American Urological Association, found use of ultrasound instead of CT reduced cumulative radiation exposure for patients and also was less expensive. The average costs were higher for those who received a CT scan ($300) than they were among those who received an ultrasound performed by either an emergency department physician ($150) or a radiologist ($200), that study found.
Authors of an American College of Emergency Physicians blog post from January wrote that in 2009, an estimated 497,000 CT scans were performed for the evaluation of renal colic (a symptom of kidney stones) totaling $152 million in medical costs. The CT is the test of choice, but physicians should think twice about using it, wrote Dr. Michelle Lin and Dr. Jeremiah Schuur, both with the emergency department of Brigham and Women's Hospital in Boston.
“Practicing cost-effective care for patients with recurrent renal colic will reduce your patients' exposure to radiation and can shorten their length of stay, both of which will improve their satisfaction,” they said.
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