PLoS: Wantedpatient-centered MRI scanners
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Although MRI tops the lists of most important medical innovations of the last 25 years, its utility has been hampered by patient claustrophobia. Claustrophobia may occur in 35 percent of all cases and lead to an aborted scan or necessitate patient sedation. Such situations can decrease the diagnostic value of the study, limit patient acceptance and reduce workflow, according to Judith Enders, MD, from the department of radiology at Humboldt University in Berlin, and colleagues.
Given recent developments in scanner design, specifically open MRI and short-bore systems, Enders and colleagues sought to assess whether a short-bore or open design is superior in alleviating claustrophobia.
The researchers recruited 174 patients with a minimum score of 1 (on a 0 to 4 scale) on the Claustrophobia Questionnaire and a clinical indication for imaging between June 2008 and August 2009. Patients were randomized to either system. The primary outcomes were incomplete MRI exams due to a claustrophobic event.
Among the 87 patients in the short-bore group, 39 percent reported a claustrophobic event. In the open MRI cohort, 26 percent reported an event. However, the difference did not reach statistical significance.
The researchers wrote, “Although the event rates indicate a potential benefit of open scanners, these exams, whether or not completed, took significantly longer.” Patients who completed their MRI exams remained in the room 31.7 minutes in the short-bore group and 42.1 minutes in the open-bore group.
Patients who had a claustrophobic event remained in the room for 3.8 minutes in the short-bore group and 8.5 minutes in the open group. “This difference was due to a significantly larger number of patients who already rejected imaging when entering the examination room in the short-bore group,” wrote Enders et al. They added that it may be an advantage to detect such events earlier as it may allow for interventions and prevent waste of exam time.
The researchers noted that the claustrophobic event rates remained consistent—at more than 25 percent—regardless of patient characteristics and the anatomical region being scanned.
Enders and colleagues honed in on a few specifics, noting that the most problematic phases of the scan were patient positioning and entry into the exam suite. They also found that the suffocation subscale of the Claustrophobic Questionnaire was the best discriminator to identify patients at increased risk for an event.
The researchers suggested a few avenues for future work, noting the potential of open mobile MR sensors. “Future clinical research should investigate more patient-centered MR scanner designs and their potential to further alleviate claustrophobia,” Enders et al wrote. In addition, they suggested procedural modifications that address the high-event phases of the study, e.g. patient positioning and exam room entry. Finally, further research focused on the Claustrophobic Questionnaire could clarify its predictive value.