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Patients with necrotizing pancreatitis typically undergo repeated computed tomography ( CT ) scanning, exposing them to high doses of ionizing radiation, yet many of these CT scans do not lead to changes in management.

In a presentation here at Digestive Diseases Week 2010, Chad G. Ball, MD, from Indiana University in Indianapolis, told attendees that the use of CT scans should be reduced in patients with necrotizing pancreatitis, and that when CT scans are deemed necessary, lower doses of radiation should be used.

"There has been an explosion in indications for the use of CT scans, along with a 6-fold increase in per capita radiation exposure from medical imaging. CT is the gold standard for patients with pancreatitis, but the ubiquitous use of CT imaging for this condition raises substantial public health concerns and mandates a careful reassessment of its utility," Dr. Ball asserted.

Dr. Ball and his coinvestigators conducted a retrospective review of all patients referred to a tertiary care center for the treatment of necrotizing pancreatitis from 2003 to 2007. The study was designed to determine the frequency of use of CT imaging, the effective radiation dose per patient, the rate of change in therapeutic intervention after CT, and the mean direct hospital costs for these patients.

Of 1290 patients with acute pancreatitis, 238 cases (18%) were necrotizing. Mean age was 53 years, 62% were male, mean length of hospital stay was 27 days, mean length of stay in the intensive care unit (ICU) was 7 days, and mortality was 9%. The median number of abdominal CT scans received was 5 (range, 1 to 28).

"Mean length of stay in the ICU increased linearly with the number of CT scans," Dr. Ball reported.

He explained that the average "effective dose" of radiation delivered varies according to the type of scanner used. Patients who undergo dual-phase scans are exposed to the highest effective dose, which is 63 mSv; these scans were used in 60% of the patients with necrotizing pancreatitis.

"This radiation exposure is higher than that from more than 3000 chest x-rays, and is much higher than other occupational exposures. However, patients with necrotizing pancreatitis have a reduced life expectancy, and less time to manifest radiation-induced cancers," Dr. Ball said.

CT scans changed interventions only 20% of the time in the overall study, and only 31% of the time in those who were most severely ill. "This is a low percentage," he noted.

The costs of treating patients increased stepwise in a linear fashion, parallel with the number of scans (P < .05); the scans themselves accounted for 5% of total hospital cost.

Restraint Urged

The formal discussant of this paper, Jeffrey Matthews, MD, from the University of Chicago in Illinois, urged restraint in the use of CT scans among all hospitalized patients, not just those with necrotizing pancreatitis.

"This is a larger question of diagnostic restraint," he said. "We should be optimizing the number of times we order a CT scan and it changes management."

He acknowledged that repeat scans are needed to document the progression of necrotizing pancreatitis. However, Dr. Ball said that although dual-phase scans are not needed, they were performed in 60% of the study population.

"This is an opportunity to reduce radiation exposure," Dr. Matthews said.

At the University of Chicago, he and his colleagues are monitoring "the reflexive ordering of multiphase studies" in patients with necrotizing pancreatitis, in an attempt to reduce the phases and frequency of these studies.

He suggested that the use of magnetic resonance imaging (MRI) could reduce the need for multiphase studies, but said that "surgeons prefer CT to MRI."

Source: Medscape Today

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