CT and MRI overused, unnecessary in mild acute pancreatitis

By Staff News Brief

Cross-sectional abdominal imaging examinations do not alter the medical management of patients with suspected mild cases of acute pancreatitis. Cost savings could be significant if a computed tomography (CT) or magnetic resonance imaging (MRI) examination could be postponed for at least 48 hours to determine if advanced diagnostic imaging really is needed, according to the authors of a recent study.

The annual cost to treat acute pancreatitis in the United States alone is estimated to be $2.5 billion for 240,000 hospital admissions and 330,000 emergency department visits.1 The majority of patients diagnosed with acute pancreatitis have have only mild, self-limiting cases, according to researchers at Emory University School of Medicine. They conducted an analysis published in the September-October issue of the Annals of Gastroenterology, their findings supporting the ACR Appropriateness Criteria® recommending transabdominal ultrasound, not CT or MRI, as the initial examination.

The guidelines developed by the American College of Radiology (ACR) give a transabdominal ultrasound a rating of 9 out of 10, an examination “essential to assess for gallstones” if patients are presenting with the first episode of acute pancreatitis and also is useful to assess for choledocholithiasis, gallstones in the bile duct. MRI is ranked 4 and CT 3, which the guidelines consider “usually not appropriate” in the first 48 to 72 hours. Beyond this period, an abdominal CT with contrast is rated 8, and recommended as “the single best, most practical examination.”2

However, this advice is often ignored say the authors, who practice at Grady Memorial Hospital in Atlanta, GA, and hypothesized that contrast-enhanced CT or MRI ordered within 48 hours for patients presenting with their first episode of pancreatitis does not affect patient management.

Paul Reynolds, MD, of the Division of Digestive Diseases, and colleagues identified 166 patients admitted to Grady with symptoms of acute pancreatitis over a 5-year period starting in 2010. Of these, 105 patients had either contrast-enhanced CT or MRI exams on the first or second day of hospital admission, and 24% had an additional repeat examination while hospitalized. Only 50 patients had transabdominal ultrasound as their only imaging examination.

The authors reported that 26% had normal findings and 53% had uncomplicated pancreatitis. Only 10% of the patients had local complications of pancreatitis. The complications included pancreatic necrosis (5 patients), acute fluid collection (4 patients), and pseudocyst (1 patient). Seven patients had biliary duct dilatation on contrast-enhanced CT, but because five patients had also undergone transabdominal ultrasound which identified the condition, the CT exam did not contribute to patient management.

They also determined that management was not affected for 18 patients who had repeat imaging within seven days, or for seven patients who had imaging for local complications more than seven days after admission.

Of 105 patients, only two, one with biliary ductal dilatation and a pancreatic mass and the other with Crohn’s disease, benefitted from CT., which changed their clinical management.

Besides preventing unnecessary radiation exposure, the analysis found that cost savings extend beyond radiology and include unneeded consultations, additional tests, or medication adjustments. “Early and repeated cross-sectional imaging is frequently performed in patients who present with acute, mild pancreatitis, but very rarely does this strategy lead to information that would not have been known if guideline-based practice had been followed,” the authors wrote.

Saurabh Chalwa, MD, associate professor of medicine and the director of endoscopy at GMH, told Applied Radiology that the hospital’s emergency physicians and administrators were surprised by the results of the study. “The intent of this study was to do a data-driven educational intervention, which we are currently in the process of implementing,” he said. Grady does not yet have clinical decision support software for radiology examinations. 

“I think the responsibility for ordering the correct imaging exam should be with the ordering clinician and not a radiologist,” said Dr. Chalwa. “In a busy hospital, it is not practical for a radiologist to review the indications for all ordered imaging exams. However, periodic audits and non-threatening feedback and education regarding the futility of unnecessary testing have been shown to go a long way in changing prevalent practices.”

REFERENCES

  1. Reynolds PT, Brady EK, Chawla S. The utility of early cross-sectional imaging to evaluate suspected acute mild pancreatitis. Ann Gastroenterol. 2018;31(5):628-632.
  2. American College of Radiology. ACR Appropriateness Criteria®. Acute Pancreatitis. Accessed at https://acsearch.acr.org/docs/69468/Narrative/ on October 21, 2018.
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CT and MRI overused, unnecessary in mild acute pancreatitis.  Appl Radiol. 

By Staff News Brief| November 12, 2018

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