U.S., Canadian Hospitals’ Stroke Imaging -- and Results -- Differ

June 3, 2011
Todd Neff

The study’s focus was on the use of CT, MRI, ultrasound and x-ray imaging given the American hospital’s far greater capacity of scanners.

 A team of American and Canadian researchers analyzing five years of patient data have found significant differences in the role of imaging with stroke patients at major hospitals in Boston and Ottawa. Most strikingly, the rate of stroke-related MRI scans at Boston’s Beth Israel Deaconess Medical Center was nearly twice that of the dual-campus Ottawa Hospital (95.75 scans per 100 patients vs. 41.39 scans per 100 patients).

In this retrospective study, authors led by Max P. Rosen, MD, MPH, of Beth Israel Deaconess and the Harvard Medical School, used data on 918 American and 1,759 Canadian patients admitted from October 2002-December 2006. The study’s focus was on the use of CT, MRI, ultrasound and x-ray imaging given the American hospital’s far greater capacity of MRI scanners (six in the 600-bed American hospital, versus two in the 950-bed Canadian hospital), its slight advantage in CT scanners (seven vs. five), and its 24/7 availability of both scanners (The Canadian systems had service gaps on weekends).

The Canadian hospital, the authors found, used comparatively more CT scans (36% of patients) than its American counterpart (26%), as well as more x-rays (49% vs. 39%).

The study also found that that statistically fewer patients in Boston died in the hospital (7.08% versus 11.31% in Ottawa), which may or may not have been attributable to differences in diagnostic imaging. To establish that, the authors suggest, a prospective, randomized study is needed.

Still, Rosen said, “Our study demonstrates that for patients presenting with symptoms of acute stroke, differences in scanning capacity (CT and MRI) may shape aspects of clinical management.”

There may have been other factors at play. The American hospital used a stroke protocol at the time of study while the Canadian one did not. The American hospital also used more anticoagulants (60% of U.S. patients received them versus 47% of the Canadian patients), and Beth Israel Deaconess shorter discharge time may have played a role, the authors conclude.

The study: http://www.jacr.org/article/S1546-1440(11)00068-8/abstract
Reference:  Rosen et al, Imaging Workup of Patients with Stroke, Journal of the American College of Radiology, Vol. 8, No. 6, June 2011.