Radiation exposure from CT scans for the diagnosis of acute pancreatitis is significant, even though the condition is often easily diagnosed with laboratory tests, Dr. Desiree E. Morgan and her colleagues reported.
Dr. Morgan of the department of radiology at the University of Alabama at Birmingham ck her colleagues looked at 869 patients who had 1,036 admissions for acute pancreatitis between October 2001 and September 2006 (mean age 51 years; 65% women). The most common etiologies included gallstones (32%) and alcohol abuse (23%).
Most patients (746 of 869) had a single hospital admission with a mean stay of 9.4 days. Those with multiple stays had a mean of 2.5 stays and 15.9 days.
Of 869 patients, 566 (65%) had at least one abdominopelvic CT scan. A total of 220 patients underwent one CT scan, 135 patients had two, and 211 received three or more.
“Patients with [Balthazar CT severity] grades A-C had mean total effective radiation dose estimated at 43.4 mSv … which was less than those with grades D-E,” who had a mean of 77.8 mSv, they wrote (Clin. Gastroenterol. Hepatol. 2010;8:303–8).
There was no correlation between CT scans and patient age. Indeed, a grade A patient aged 30 years or younger had a higher mean effective radiation dose estimate (34.38 mSv) than did a patient older than 70 years (33.78 mSv). The same pattern was seen in grade E patients (68.82 mSv vs. 57.91 mSv).
“Since the impact of radiation dose on cancer risk is greatest in young patients and less significant in older patients, we are alarmed that there was no attempt to limit exposure by employing alternate imaging strategies in our younger patients with severe pancreatitis,” they said. These might include “educating referring physicians about imaging utilization” and “performing single phase rather than multiphasic exams.”
Abdominal imaging using newer MRI units capable of breathing-independent MRI sequences and more rapid examinations also may be a valid alternative to CT, they added.
Dr. Morgan conceded several limitations to the study, including the fact that “individual patients' radiation exposure estimate was calculated using published average CT effective dose estimates rather than true measurement at the time of scanning.” However, “because our calculations did not take into account CT scans of other body regions in our patients or CTs obtained elsewhere … we have likely underestimated exposure,” she added.
“In the U.S., the average person receives an effective dose of about 3 mSv per year from naturally occurring radioactive materials and radiation from space. A typical CT scan produces the equivalent of more than 3 years of natural, background radiation,” the authors noted. “Discussion … regarding the merits and appropriateness of additional CTs in younger acute pancreatitis patients should be a priority.”
Disclosures: Dr. Morgan and her colleagues reported no relevant conflicts of interest.