Portable CT benefits stroke patients

Margaret W. Bushee, margaret.bushee@laurin.com

Stroke, as reported by the National Institute of Neurological Disorders and Stroke (NINDS), is the third leading cause of death in the US, with 700,000 cases diagnosed annually. NINDS recommends that those arriving at an emergency room with signs of acute stroke be given a computed tomography (CT) scan within 25 minutes. Besides confirming the diagnosis, the scan identifies whether the stroke is ischemic – caused by a blood clot blocking a blood vessel – or whether it is bleeding.

According to Dr. David B. Weinreb, a radiology resident at the Hospital of St. Raphael in New Haven, Conn., most stroke patients are taken to small community hospitals, which do not always have a scanner available and, even if the facility does have one, it might not be near the emergency room, creating a time-consuming delay for a patient in distress.

Weinreb, lead author of a recent study on the benefit that stroke patients receive from a portable CT in the emergency room, said that the scanner is essential for the timely treatment of ischemic stroke patients, who must be given tPA (tissue plasminogen activator), a clot dissolver, within a three-hour window. The CT scan also is necessary to verify that there is no bleeding in the brain.

“TPA is usually the only shot we have at clot-induced ischemic strokes,” he said, “but it needs to be administered in a closely monitored situation, because the drug can have extremely adverse effects in those patients whose strokes are instead due to bleeds.”

The study, conducted at North Shore Medical Center-Salem Hospital in Salem, Mass., was presented in December at the annual meeting of the Radiological Society of North America but has yet to be published. Time intervals between physicians’ scan orders and the scans themselves were measured for one month before an eight-slice portable scanner was acquired and for four months after it was installed.

During the one-month period, 127 patients waited 34.55 ±2.2 minutes for a scan, whereas during the four-month period, 281 patients waited 15.88 ±2.4 minutes, or 54 percent of the previous time lapse. Discrete event simulation modeling showed that, when a portable CT was accessible, the delay between onset of symptoms and scan showed a change from 4.16 to 3.76 hours, or a reduction of 9.6 percent.

According to this model, the number of patients who could be provided thrombolytic therapy within the three-hour treatment window would increase 86 percent, from 0.59 to 1.1 percent. The difference, 0.51 percent, could provide a benefit to 3570 patients annually over the 4130 patients who would be treated within this window without the portable CT in the emergency room.

Weinreb concluded that community hospitals with portable CTs would provide stroke patients with the advantage of rapid evaluation. “The hospital’s acquisition of a portable CT scanner facilitated more rapid assessment of acute stroke patients and is anticipated to increase the number of patients to whom thrombolytic therapy can be administered.”