After developing and implementing a tiered MRI prioritization system based on patient severity, the emergency department at Lahey Hospital & Medical Center in Massachusetts successfully cut its overall average order-to-imaging start times from 4.1 hours to 2.7 hours.

The radiologists and ED members behind the win describe their project in an article published online June 27 in Current Problems in Diagnostic Radiology.

The site of the study was a 24/7 suburban tertiary care, comprehensive stroke and Level II trauma center with three onsite MRI scanners.

During the project, Juan Small, MD, MSc, Jacob Kim, MD, and colleagues assigned ED patients to one of three unambiguous, hierarchically defined tiers—critical, emergent or urgent (tier 1, tier 2 and tier 3, respectively)—upon initial assessment.

Each tier was accompanied by consensus-driven guiding clinical definitions:

Tier 1: Critical patient in need of immediate response. “A patient’s life or limb is at risk,” the definition reads, “or the patient may need TPA” (for tissue Plasminogen Activator, the blood-clot dissolver). “Only 1 body part will be scanned, and the result will drive major changes in medical management.”

Tier 2: Emergent patient in need of rapid response. “Only 1 body area should be scanned. The results will drive major changes in the medical management, with the intention to treat.”

Tier 3: Urgent patient in need of emergency-level medical care.

This system replaced traditional order prioritization, which uses often-ambiguous nominal categories such as STAT, “wet reads,” urgent, as soon as possible or routine, the authors note.

They also tied each prospective imaging order to a specific target for order-to-imaging start time.

Retrospectively analyzing various month-by-month performance indicators of the tiered system one year after implementation, the researchers found average overall wait time from order time to begin scan time for all ED MRIs decreased from 245 minutes (4.1 hours) at baseline to less than 136 minutes (2.7 hours).

They also found an inverse relationship existed between ED MRI order-to-imaging start time and the tier severity into which the patient was stratified.

Further, only 4 percent of the ED-specific volume was truly critical (tier 1), while tier 3 MRI exams constituted an eye-opening 75 percent of the ED volume.

Finally, month-by-month quality assurance analysis showed consistent completion of exams under or close to the target times tied to each tier, the authors report.

“Our systematic approach allowed us to effectively determine the order of importance for each ED MRI imaging order,” Small and colleagues write. “By setting unambiguous explicit priorities, we were able to judiciously allocate MRI resources for appropriately timed and effective services. Our current ability to accurately predict a target performance time allows us to set accurate expectations for both providers and patients.”