At its inception in the 1990s, a telestroke consult required that the physician use a fixed workstation and in some cases a second computer for documentation of the encounter or reviewing films. However, because the “time is brain” concept mandates instant access to the patient for a rapid evaluation for potential therapy, this was not an ideal 24/7 telestroke model.
Telemedicine workstations continue to exist in the hospital or physician's office, but are complemented by more mobile technology options such as laptops, tablets, and smart phones. Cloud-based technology (circa 2006) facilitated doing telestroke consultations using these mobile technologies. Consultations can be provided wherever there is a secure Internet connection and via “hot spot”–generating cellular connections. These advances allow the provider significant access to web-based tools for documentation, imaging, and electronic medical records review.
Furthermore, telestroke-tailored, software-bundled applications allow for live video consultation (VC) encounters, with the consultation documentation and the HCT imaging for review, all into one convenient screen. The development of “multipoint” capacity, having more than two terminals connected by a single communications channel, allows for two or more physicians to join the VC encounter and confer on the clinical case. For example, the neurointerventionalist can enter the call to discuss the candidacy of a patient with the stroke neurologist “live” and directly with the ED physician, the patient, and/or their family.
Brain/Vascular Imaging Transfer (Teleradiology)
First conceived in 1982, Picture Archiving and Communication Systems (PACS) is a medical imaging-based technology that provides convenient access to images from multiple modalities. PACS allows electronic images and reports to be rapidly transmitted digitally via a PACS link. In the United States, the University of Kansas developed one of the first PACS, and the University of California Los Angeles deployed pilot PACS in their pediatric radiology department. The first filmless fully digital radiology department using PACS was in the Danube Hospital in Vienna in 1991. The current PACS is critical for fast interpretation of head CT scans in the evaluation of the stroke patient who may qualify for the time-sensitive thrombolytic TPA. Today, most PACS can be accessed securely using cellular or Internet connections.
Telestroke patient imaging includes an emergency noncontrast CT brain scan to identify any intracranial hemorrhage (which is a contraindication for thrombolytic treatment). In selected cases, CT angiography of the head and neck, brain magnetic resonance imaging (MRI), and/or magnetic resonance (MR) angiography are obtained. A newer modality, a multiphase CT, has been used to assist in the selection of patients who may benefit from thrombectomy. This technique generates time-resolved cerebral angiograms of brain vasculature from the skull base to the vertex in three phases after contrast material injection. By evaluating the potential for collateral vessels at the later phases, the teleprovider can better predict outcome.
VC equipment has advanced tremendously since the first “peer to peer” VC device proposed by AT&T at the New York's World's Fair in the 1960s. The technology improved with the introduction of the Network Video Protocol, and in the 1980s, the availability of digital transmission of voice and video by electrical pulses, through the Integrated Services Digital Network. In 1991, IBM introduced the first personal computer VC product, followed by Multipoint VC by Apple Macintosh. In 1995 the first VC occurred internationally between North America and Africa. During this time frame, high-capacity broadband services and more powerful computing processors followed high-definition systems, “icloud” applications, and lower-cost video-capturing technologies, leading to today's highly sophisticated VC equipment and systems. A critical shift occurred from company-based proprietary equipment and software to standards based technology. The Unified Communications Interoperability Forum (UCIF), a nonprofit alliance between communications vendors, was launched in May 2010. The UCIF created VC standards and protocols to ensure interoperability regardless of the platform.
Telestroke VC equipment requires the ability to perform an observational bedside assessment that includes components of alertness and cognition, vision, speech, motor, sensory, and coordination (ie, NIHSS). Optimally the system has a high-definition, remote-controlled video camera with a “pan-tilt” and zoom capability, or “PTZ,” camera. In addition, omnidirectional microphones are essential for quality sound transmission.
Current Internet speeds can easily handle transmission of most radiological images required to evaluate the patient. Cellular 4G (50 Mbps download/350 Mps upload), broadband wireless (600 Mbps – 2007), and LAN/fiber-optics (10 Gbs – 2010) will undoubtedly continue to advance in the future. Initiatives to expand the footprint for telemedicine include federal programs, such as the FCC's Connect America Fund (https://www.fcc.gov/encyclopedia/connecting-america) and HRSA's regional funding of Telehealth Resource Centers (http://www.telehealthresourcecenter.org).
The evolution of mobile media, or m-health, will also shape the future application of mobile technologies in telestroke. 38 Telestroke assessments have been validated across a range of mobile endpoints, including smart phones and tablet-based devices. 39–41 Advances in mobile imaging may lead to the ability to evaluate brain hemorrhage using handheld devices in the future. 42
Regarding security, telestroke providers must ensure that telemedicine networks are secure and encrypted. Although this is crucial, doing so without compromising the real-time flow of voice and video is challenging. The American Telemedicine Association has issued guidelines for a variety of subspecialties, and currently, FIPS 140-2, known as the Federal Information Processing Standard, is the U.S. government security standard used to accredit software encryption standards and lists encryption techniques such as AES (Advanced Encryption Standard) as providing acceptable levels of security. 43 All providers must use extreme caution and restraint in using personal devices to provide clinical care.