Over the past 20 years, the use of CT in the emergency department (ED) has more than tripled, but it’s not clear what effect it has on physicians’ diagnoses. Since CT comes with a high cost and radiation dose, it’s important to know how useful it really is.

“It’s more of an issue of whether the risk-benefit calculus is the right one,” says Dr. Pari Pandharipande, director of the Massachusetts General Hospital Institute of Technology Assessment. “That is a source of ongoing policy dialogue in the health care community regarding CT.” Pandharipande and her fellow researchers decided to investigate what effect CT has on ED physicians’ diagnoses and management decisions. Over the course of 15 months, they assessed CT use at four U.S. academic medical centers.

The ED physicians participating in the study evaluated patients with abdominal pain, chest pain/shortness of breath and headaches, and filled out a survey after their initial evaluation that gauged their confidence in their diagnoses, and another survey after receiving results from the CT exam that asked if their initial diagnosis changed.

After 245 physicians completed both surveys for 1,280 patients, the researchers found that after CT, the physicians’ initial diagnoses changed for 51 percent of patients with abdominal pain, 42 percent of patients with chest pain/shortness of breath and 24 percent of patients with headache. In addition, CT helped them either confirm or rule out alternative diagnoses 95 to 97 percent of the time for all indications.

“We always want to try to get rid of unnecessary tests — it’s better for people not to have tests that they don’t need,” says Pandharipande. “With this study, we had fairly pronounced results in terms of changes in physician decision-making before and after CT.” Though CT led many physicians to change their diagnoses, that doesn’t preclude the need to constantly get better at trying not to order studies patients don’t need, she adds. The proportion of patients who had diagnoses that changed can either be viewed as a large number or it could be viewed as having a lot of room for improvement, says Pandharipande.

The use of CT in the ED will likely continue to increase because of the unique window it offers into a patient’s health. The risks associated with the technology will also remain, but manufacturers are working to lessen them.

Faster scans and lower dose
In trauma situations, ED physicians must make decisions fast without sacrificing accuracy. Also, health care reform is demanding that they take into account quality and costs more than ever before. Memorial University Medical Center (MUMC) in Savannah, Georgia, has over 95,000 emergency visits and almost 3,000 trauma patients per year. When it had to update its CT systems in 2011, the facility decided to install Toshiba’s Aquilion ONE CT.

One of the major concerns about using CT is the radiation dose. To address that, Toshiba built its Adaptive Iterative Dose Reduction 3D (AIDR 3D) technology into the system, which has been shown to lower radiation exposure by up to 75 percent compared to traditional filtered back projection reconstruction.

With the technology, MUMC was able to maintain lower dose for any patient shape and size without compromising image quality. It was especially useful for pediatric patients because of the harmful effects that radiation can have on children. Many of the other major manufacturers offer iterative reconstruction technology for their CT systems. Philips Healthcare has its iDose 4 iterative reconstruction technique, GE has its ASiR dose reduction technology and Siemens has its ADMIRE technology.

ADMIRE, which is Siemens’ third-generation iterative reconstruction technology, makes images appear as though the patient has received 100 percent dose, despite the fact that the dose has been significantly reduced, says Christine Ziemba-Landon, CT product manager at Siemens. “Even though we have reduced the radiation dose upfront, ADMIRE allows us to clean that image up, reduce artifacts and give them the appearance of a really nice image,” she adds. To significantly reduce the dose, ADMIRE is combined with Siemens’ Stellar Detector, X-CARE and CARE kV technologies. “The industry is saying, ‘You need to reduce radiation,’ and the only way you can do that is by using dose reduction features,” says Ziemba-Landon.

When patients with metal prosthetics or gunshot-wound victims with bullets inside their body require CT exams, physicians usually have to accept that the image quality will suffer. The metal artifacts can hide anatomical structures that the physicians need to see.

However, Toshiba’s Single Energy Metal Artifact Reduction (SEMAR) technology minimizes the streaks and artifacts on images that metal objects cause. MUMC was able to provide more information to the radiologists, which led to more accurate diagnoses and better overall outcomes for the patients. The Aquilion ONE can perform a cardiac CT in one rotation or .35 seconds, compared to standard CTs that can do that in five to six seconds. In addition, it provides 16 centimeters of coverage compared to typical scanners, which only cover four centimeters.

Time equals brain
CT is not only making strides inside of the hospital — it’s also starting to be used in ambulances for stroke patients. The trend originally started a few years ago in Germany, but it is now making its way to the U.S. Cleveland Clinic, The University of Texas Health Science Center at Houston (UTHealth), Mercy St. Vincent Medical Center and the University of Colorado Hospital are a few of the institutions leading the way with this concept. Cleveland Clinic deployed its first mobile stroke unit in June 2014 equipped with Neurologica’s CereTom mobile CT scanner.

The unit looks like an ambulance on the outside, but inside it is equipped with a portable CT scanner and a staff made up of a paramedic, critical care nurse, CT technologist and EMS driver. The CT is used to image the patient’s brain and determine whether the stroke is caused by a blood clot or ruptured blood vessel.

If a blood clot is the cause, the medical team can administer the intravenous tissue plasminogen activator (tPA) within three hours to try to break up the clot and that may improve the chance of recovery. TPA is currently underutilized since mobile stroke units are not yet the standard of care and only a small portion of patients arrive at the ED within three hours of the time they were last known to be well, according to the Massachusetts Department of Health and Human Services. UTHealth’s mobile stroke unit is also equipped with the CereTom CT.

At the American Stroke Association’s International Stroke Conference 2015 in March, UTHealth reported that it was able to administer stroke treatment within 10 to 18 minutes of arrival and that over the course of nine weeks, two patients per week were treated with tPA and 40 percent were treated within the first hour from onset.

Mobile stroke units are equipped with portable CTs because of their small footprint, but Siemens Healthcare has a mobile stroke unit currently in production that is equipped with its SOMATOM Scope CT, which received FDA approval in September 2014. Even though it’s not a mobile system, it only requires 130.2 square feet of space.

“The idea behind it is that you can potentially eliminate spending time in the ED in situations where time plays a critical factor in positive outcomes,” says Dena Bobbett, product manager of neuroradiology and emergency department CT marketing at Siemens. “You could go straight to CT if you wanted to get a neuro perfusion study or you could go straight to the angiography suite.”

Nearly automatic ultrasound
Just like CT, ultrasound is also making its way into ambulances. Last year, six emergency vehicles in the Dallas and Forth Worth metropolitan areas deployed Samsung Electronic America’s PT60A ultrasound to diagnose trauma, internal bleeding, acute abdominal pain and cardiac arrest. During a trial that started in July 2014, the emergency vehicles made 91 emergency calls by October. In one case, a patient was experiencing abdominal pain and the paramedics used the PT60A and found the patient’s liver was bleeding.

The paramedics transmitted those images, in real time with Trice Imaging’s mobile encryption and image management system, to the hospital and the staff was able to make sure the right specialists would b available when the patient arrived. For point-of-care ultrasound systems used inside of the hospital, there is a trend toward a fit-for-purpose ultrasound designed specifically for the emergency space. Ultrasound systems are also being designed specifically for the critical care and anesthesia fields.

With traditional ultrasound, a clinician’s job is to get an image that is so compelling that it influences another physician to do something. But with point-of-care ultrasound, the physicians’ only job is to convince themselves. “They both care about image quality and they both care about seeing well, but their purposes are quite different,” says Paul Mullen, general manager of point-of-care ultrasound at GE Healthcare. Industry experts believe that hand-held, pocket-sized ultrasound systems will eventually replace stethoscopes in the ED. A few of the systems on the market are GE’s Vscan, Siemens’ ACUSON Freestyle, Philips’ Lumify and SonoSite’s iViz.

When patients show up in the ED with very low blood pressure, the physicians are usually worried about them surviving. When the physician uses the point-of-care ultrasound to image the patient’s heart, it might be determined that the left ventricle is slightly small. The physician would then lift the patient’s leg to allow the blood to flow out of the leg and into the inferior vena cava vein, which should then fill the left ventricle. If it does, the physician will see a nice cardiac response and give fluids to the patient to deal with dehydration.

“You need to completely change the workflow of the ultrasound machine and show that you can facilitate this quick train of thinking,” says Mullen. “The imaging happens nearly automatically — it doesn’t have to be perfect, but it has to be nearly automatic because no one wants to take the time to push buttons.”

Mullen believes that point-of-care ultrasound will replace other modalities like CT or MR when imaging pediatric patients in the ED. Because of the harmful effects radiation may have on children, hospitals are looking to avoid exposing them to it. Point-of-care ultrasound will also replace other modalities when speed is a major priority. For example, resuscitation is a case where there is no time to perform a CT exam. “I think that where possible we are going to ultrasound, instead of using radiating technology for the care of the most vulnerable patients we have,” says Mullen.