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Globally, stroke is the second leading cause of death above the age of 60 years, and the fifth leading cause of death in people aged 15-59 years old. In many developed countries the incidence of stroke is declining even though the actual number of strokes is increasing because of the aging population. In the developing world, however, the incidence of stroke is increasing. In China, 1.3 million people have a stroke each year and 75% live with varying degrees of disability as a result of stroke. The predictions for the next two decades suggest a tripling in stroke mortality in Latin America, the Middle East, and sub-Saharan Africa.

Providing advanced stroke diagnosis

The computed tomography (CT) image below was captured by Philips Healthcare's newest computed tomography (CT) scanner, the Brilliance iCT. Below, the image on the left shows damage caused by a type of stroke known as a large medial cerebral artery (MCA) infarct. The MCA is the largest cerebrovascular artery, and is the most prone to cerebrovascular accidents. In this CT image below, damage from the stroke can be seen on the left side of the patient's brain. To provide a frame of reference, the image on the right (below) is an example of a CT scan of a normal brain, without any stroke damage, to provide a frame of reference and illustrate the effects of stroke on the brain.

Common symptoms experienced during an MCA stroke, such as the one depicted in first CT image, may vary. They may include paralysis or weakening and reduced sensitivity on the right side of the patient's body, and loss of vision in the right visual field of both eyes. In addition, the patient's ability to speak would likely be impaired, as well as others understanding the patient's speech. The patient may have right-left confusion, a loss of the ability to distinguish the fingers on the hand, and a deficiency in the ability to write or comprehend mathematics. Lastly, changes in the sensation of touch, pain or temperature may occur.

Philips Healthcare provides a comprehensive clinical solution to help clinicians treat stroke patients. Our solution includes the advanced imaging capabilities of the Brilliance line of computed tomography (CT) scanners- including the Brilliance iCT- and the Advanced Brain Perfusion application. This application permits rapid diagnosis and supports physiologically-based treatment decisions via Philips' innovative Summary Maps-- to quickly identify potentially salvageable brain tissue.

Philips researches decision support software to facilitate stroke care

When someone suffers a stroke, every second counts. According to the World Health Organization, more than 15 million people suffer from stroke each year worldwide. When stroke hits, rapdi treatment can make the difference between life and death as oxygen-deprived brain cells begin to die at the alarming rate of 32,000 per second.

Stroke is the third leading cause of death and the number one cause of disability in North America and Western Europe. But the number of healthy survivors could be much larger if treatment is administered more rapidly. Unless a stroke is treated within a few hours, victims are likely to suffer significant, and often permanent, disability - if not death.

Rule of thirds

According to Jon Barrick, Chief Executive of The Stroke Association, "Stroke clinicians talk about a 'rule of thirds' with stroke - that a third are likely to die, a third become permanently disabled and a third recover. We believe that 'rule of thirds' can and should, urgently, be broken. If the time between the onset of a stroke and diagnosis was no more than three hours, a significant number of people could have a much better chance of avoiding death or becoming disabled. All too often, there are severe delays."

Many of the delays Dr Barrick refers to are often a result of the varying symptoms of stroke that can differ widely from one patient to another and often mimic other conditions. Adding to the difficulty of diagnosis, the signs of a stroke may begin suddenly or develop over many days - sometimes even temporarily improving - depending upon the type of stroke and area of the brain affected.

To ensure that potential stroke patients get treatment as quickly as possible, emergency paramedics must make a preliminary diagnosis within minutes. To help them, screening tools, such as the Los Angeles Prehospital Stroke Screen (LAPSS), have been developed to give paramedics a set of questions and a corresponding decision 'tree' to help determine if a stroke alert should be sent to the nearest hospital.

When time is critical

The rapid rate of new healthcare technology begs the question: surely we can find a way to speed up the treatment process? It's possible, but quick treatment demands quick diagnosis.

The new 'Stroke Angel' software, developed by Philips Research, helps accelerate the process from the start. Running on a standard handheld computer, the Stroke Angel helps paramedics determine if the victim has indeed suffered a stroke by computerizing standard screening tools such as the LAPSS. Using the victim's information as entered by the paramedic, the Stroke Angel assesses the situation and then recommends whether or not to send a stroke alert.

It also pinpoints the most suitable stroke-care unit (for example, the nearest hospital with a dedicated stroke team). This is key, as often paramedics don't know or remember which hospitals are equipped to give stroke victims the life-saving treatment that some require. In fact, several studies have shown that stroke patients fare significantly better when treated by dedicated stroke teams with specialized protocols.

Speeding up the diagnosis process even further, the Stroke Angel wirelessly transmits the stroke alert to the hospital together with the victim's screening information. This gives the hospital time to make preparations - such as alerting the stroke team and freeing up critical resources such as a CT or MRI scanner so that diagnosis and treatment can begin as soon as the patient arrives.

The right diagnosis

Once the patient arrives at the hospital, stroke diagnosis is still not easy - even for experienced stroke specialists. All too often, stroke patients suffer from disorientating symptoms that can cause confusion and disable the patient's ability to communicate clearly with doctors. And a doctor must not only determine if the patient has suffered from a stroke but also which type of stroke from several possibilities - a life or death decision in itself.

The two most common types of stroke are ischemic stroke and hemorrhagic stroke. Ischemic stroke, which accounts for around 80% of stroke cases, is caused by a blocked blood vessel typically due to a blood clot, which blocks blood flow to a certain part (or parts) of the brain. Blood clots can form either within the brain itself or travel to the brain from other areas of the body.

The second most common type of stroke is hemorrhagic stroke caused by bleeding within the brain or surrounding tissues resulting from a ruptured blood vessel. This type of stroke not only prevents blood from reaching parts of the brain but can also damage brain tissue around the hemorrhage site and result in a build-up of pressure in the skull, causing extensive and often life-threatening damage.

Different treatments

Making a so-called 'differential diagnosis' between these two types of stroke is extremely important because the treatments are radically different. In fact, the treatment for ischemic stroke can be fatal if administered to a hemorrhagic stroke victim. For this and many other reasons, stroke is a potentially life-threatening condition that can deteriorate quickly unless the right diagnosis and treatment decisions are made. With the pressure on, doctors have to be vigilant at every point in the care cycle.

To help with this, Philips Research created the 'Stroke Navigator' to provide hospital clinicians with a valuable tool to support and coordinate diagnosis and treatment. Linked to the hospital's patient information system, it builds a complete patient profile based on the screening information and patient history, then tracks every procedure performed together with test results. This information is combined with pre-programmed expert knowledge, probability rates and clinical decision guidelines for the treatment of stroke. The Stroke Navigator then analyzes the situation and gives diagnostic and therapeutic support and suggestions.

"With Stroke Angel and Stroke Navigator, we've tried to bring more simplicity to stroke diagnosis by making it easier for paramedics and physicians to pull together all the information they need to make the best decisions," explains Charles Lagor, Senior Research Member at the North American division of Philips Research.

With the right information, for example, the Stroke Navigator can provide a continuously updated probability of whether the patient has suffered an ischemic stroke, a hemorrhagic stroke or whether the patient is a so-called 'stroke mimic' (someone suffering from a non-vascular disease that produces stroke-like symptoms). Then, based on the guidelines and probabilities, the Stroke Navigator suggests the appropriate next steps for treatment, together with single-click operations to initiate them - such as requesting an urgent CT scan.

"Such tools don't require the development of new technology," Charles notes. "What they do require is a thorough understanding of clinician and patient needs so that you can apply existing technologies in innovative ways."

Following a stroke, victims cannot afford to lose time. In fact, every minute that goes by is a matter of life or death. And in this fight for survival, combining technology and innovation can have a real impact: it can save lives.