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Obese Gastric Bypass Patients Too Big for Imaging Devices: Presented at RSNA

By Ed Susman

CHICAGO, IL -- November 28, 2007 -- Morbidly obese patients who undergo bariatric surgery and then experience complications are often too big to undergo routine diagnostic tests.

For example, if a person weighs more than 350 lbs -- and is obviously at risk of heart disease -- that individual cannot receive a diagnostic angiography because the standard angiography table cannot support that much weight. And if a computer tomography scan is required and the patient weighs in excess of 450 lbs, that person, likewise will have to undergo risky open surgery because the scanning devices cannot handle that much weight.

"When patients weigh more than 450 lbs, standard diagnostic imaging often cannot be used. In these cases, physicians must resort to other means of diagnosis, such as exploratory surgery or using less accurate or more invasive techniques," said Raul Uppot, MD, Lecturer in Radiology, Harvard Medical School, and Assistant Radiologist, Massachusetts General Hospital, Boston, Massachusetts, United States, in a presentation here at the 93rd Scientific Assembly and Annual Meeting of the Radiological Society of North America (RSNA).

Dr. Uppot and colleagues reviewed records of 1,188 bariatric surgery patients treated at Massachusetts General Hospital from June 1999 through April 2007 to identify patients weighting more than 450 lbs who sought treatment at the emergency department following surgery.

"Morbidly obese people may be too heavy for standard tables used for these devices," said Philip Alderson, MD, James Picker Professor and Chairman of Radiology, Columbia University, New York, New York, United States. "These people may be too large to fit in tubes such as magnetic resonance imagers (MRI). And the excess fat may prove to be too much for standard X-rays to penetrate. It is a problem that we increasingly have to face with these very large individuals."

Dr. Uppot said these limits are especially problematic in light of the increasing number of morbidly obese patients who are undergoing bariatric surgery, which exposes patients to the risk of complications that often require computed tomography (CT) scans or MRI to diagnose.

He said that 27% of bariatric patients who sought emergency treatment following surgery had treatment delayed because they were too big to fit available scanners.

Imaging technology, according to Dr. Uppot, has been designed for leaner patients than those who make up a growing number of morbidly obese Americans. "Standard x-ray has a limit of 350 pounds," he said. "MRI has a 450-lb limit. Open MRI units can accommodate patients up to 550 lbs, but these are usually located outside hospitals and have a lower image quality."

In their study, Dr. Uppot and colleagues found that among the 1,188 patients who underwent bariatric surgery, 44 patients (average weight 504.9 lbs) had complications that required treatment at the emergency department. Of those, 12 patients needed imaging studies but were too large for the standard imaging equipment available at the hospital.

These patients had an average delay of 18 days before their condition was diagnosed correctly and treated. One patient had a delay of 124 days before diagnosis and treatment. This patient, who presented with abdominal pain and weighed 504 lbs, was able to lose 79 lbs while waiting for a definitive diagnosis. As a result the patient fit into a CT scanner, which confirmed nonspecific inflammation as the cause of the pain, Dr. Uppot said.


[Presentation title: Are We Meeting the Imaging Needs of the Obese? A Longitudinal Study of Patients >450 lbs Who Underwent Gastric Bypass Surgery. Abstract SSJ04-06]

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