Open MRI reduces patient claustrophobia, study confirms

Wednesday 19th December 2007

MRI offers powerful diagnostic information for various diseases and conditions. But no matter how useful the modality is in the abstract, if patients cannot relax enough to allow the scan to be performed, it will have no practical effect.

Researchers in the department of radiology at the Charité Campus Mitte in Berlin, Germany, evaluated how much claustrophobia was mitigated by using MRI scanners with 97% acoustic noise reduction and a short and wide magnetic bore versus conventional scanners.

Dr Marc Dewey presented the study's findings at the 2007 RSNA meeting in Chicago, USA.

One to 15% of all patients who undergo MRI experience claustrophobia, with an average of 2.3% having claustrophobia that hinders the exam from being performed, according to Dr Dewey.

And since these figures were based on studies of fewer than 18,000 patients, the number of people affected by claustrophobia during MRI was probably much higher.

"More than 30 million MR scans are conducted each year around the world, but with the small study populations that have been used, we actually don't know the real impact of claustrophobia on patients," Dr Dewey said.

The study included 55,734 consecutive patients over the course of eight years, from 1997 to 2005.

Dr Dewey and his colleagues performed multiple logistic regression analysis to adjust for the nonrandomised design of the study and calculated adjusted odds ratios.

Women, middle-aged people and patients undergoing head-first examinations demonstrated the highest levels of claustrophobia, Dr Dewey said.

Of the total cohort, 42,998 patients had claustrophobic reactions on a conventional MR scanner, while 12,736 patients had claustrophobic reactions on an open scanner.

Sedation was necessary in 610 patients and was effective: only two of those 610 were unable to continue with the exam despite the sedation.

The group found that the rate of claustrophobic reactions was lower with the open MRI scanner, at 0.7%, than it was with the conventional scanner, at 2.1%.

"The claustrophobia rate was reduced by a factor of three just by using this patient-friendly scanner," Dr Dewey said.

"With the conventional scanner, we had one claustrophobic event each day, but with the modern scanner, we have one event every 30 days."

Why is it important to reduce claustrophobia? Because claustrophobia affects patients as well as the efficacy of the practice.

"Bringing the patient into the focus of medical innovations has the potential to reduce costs, improve workflow, and increase clinical utility of MRI imaging," Dr Dewey said.

RSNA