On A Roll
Mobile imaging units are proving their utility in many ways.
In an effort to reach patients either more quickly or at all, a growing number of health systems are loading their imaging capabilities on wheels and taking their "show" on the road. Here's a look at three mobile imaging units—one for stroke, one for lung cancer screening, and one for breast cancer screening for women veterans—that are directly bringing needed health care to patients where they live.
Time Savings The University of Tennessee (UT) Health Science Center College of Medicine launched its comprehensive mobile stroke unit in the summer of 2016. It serves the entire city of Memphis and is on the road 15 days per month from morning until early evening. "The number of stroke calls goes down after dinner and, because of that, we operate from 8 AM to 8 PM," says Andrei V. Alexandrov, MD, RVT, chairman of the department of neurology at UT Health Sciences Center and Semmes-Murphey Professor.
The mobile stroke unit answers about four or five 911 calls a day. "Fifty percent of the time, dispatchers call you to the scene for a stroke, and it's not a stroke," says Anne W. Alexandrov, PhD, RN, CCRN, NVRN-BC, ANVP-BC, AGACNP-BA, FAAN, chief nurse practitioner (NP) for the mobile stroke unit and a professor with the UT Health Science Center's College of Nursing. However, if the NP on site suspects that the patient likely had or is having a stroke, she can arrange for a head and neck CT to be done onboard within minutes in a driveway or on the street outside the patient's location. The only caveat is that the mobile unit must be parked on level ground for the scan to be performed. The driver of the truck is tasked with making certain that it is.
The mobile stroke unit has a Siemens Healthineers 16-slice CT scanner. Because it is 16-slice, it became the first mobile stroke unit in the world to achieve accreditation from the Intersocietal Accreditation Commission. In May 2018, it received a three-year accreditation in the areas of neurological CT, acute stroke, and vascular CT angiography (CTA).
The Siemens scanner has an ultrafast scanning time and a large donut, Anne Alexandrov says. "Because of this, we can get CTA from the aortic arch straight up through the entire brain. Other mobile stroke units that are out there are using 8-slice CTs with small donuts, so if they choose to perform CTA it will include only the circle of Willis." The Siemens scanner takes only about 3 1/2 minutes for both the noncontrast CT and the CTA to be completed and ready for review.
The onsite NP looks at the CT scan as it is being acquired and determines whether the patient is bleeding. She also determines whether to administer the clot-dissolving drug tPA after consulting with the vascular neurologist on call. The sooner tPA is administered, the more effective it is likely to be.
The results of the scan are saved onto a USB stick and transported with the patient to the hospital. Then, it is uploaded to the hospital's PACS, and later it is officially read for the record. The scan quality allows patients to go directly through the emergency department and into the interventional suite without stopping for additional scanning, Anne Alexandrov says. "We've never once had to repeat the scanning in the hospital because of image quality. Our mobile stroke unit is essentially the emergency department for these patients." The patients are scanned exactly the same way they would be scanned in radiology departments, Andrei Alexandrov adds.
"Our median time from arrival on the scene to administration of tPA in the field is 13 minutes," Andrei Alexandrov says. The unit is operating on a 15-day schedule as part of a multicenter study aiming to demonstrate that mobile stroke units treat patients faster, are as safe as hospitals, and, possibly, produce better outcomes because of ultraearly treatment, he says. Several mobile stroke units are in use throughout the country, in Houston—which was the first unit in the United States and third in the world; Cleveland; Denver; Toledo, Ohio; Los Angeles; Chicago; New York; and Atlanta. Northwestern Medicine's Central DuPage Hospital in Winfield, Illinois, has the only other 16-slice CT aboard its mobile stroke unit, which launched in 2017.
The 15-day per month schedule will allow researchers to compare data and see whether faster treatment time translates to better patient outcomes. The goal of the mobile stroke unit is to be able to diagnose and treat stroke within what's known as the "golden hour," the first 60 minutes after the onset of symptoms. "We have collected every case over the last two years, and we already know that we are treating stroke patients on average 72 minutes faster if they are picked up by the mobile stroke unit," Andrei Alexandrov says.
Andrei Alexandrov is certain that more health systems will employ mobile units, especially now that the Centers for Medicare & Medicaid Services is moving toward better reimbursement of telehealth services, including administering tPA in the field. "I have a feeling that mobile stroke units are here to stay," he says.
Reaching Out As with stroke, the sooner patients are diagnosed and treated for lung cancer, the greater their chance of survival. Most patients with lung cancer don't have symptoms until the disease is adv