PET Scan Predicts If Patients Will Wake Up From Coma

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When a family member is in a coma after a head trauma, you might give anything to know whether that person will ever wake up. Now researchers have found a way to use accessible PET Scans to accurately predict whether an unconscious person will recover.

Only the most severe traumatic brain injuries result in coma or long-term unconsciousness. When they happen, it can feel like your entire family’s life is on hold, waiting for your loved one to wake up. But as a person remains unconscious for days or weeks, even months, it can be hard to know whether he or she will ever wake up.

Now, researchers may have found a way to answer that question. Researchers from the University of Copenhagen Johan Stender and Ron Kupers, also of Yale University, have published a study showing how doctors can use PET scans to predict coma recovery.

The study tracked 131 patients with disorders of consciousness, including coma, minimally conscious states, and vegetative states, along with 28 healthy control samples. Researchers used PET Scans to measure the glucose being consumed by the patients’ brains.  They found that patients in a state of unresponsive wakefulness had 38% as much activity in the most active hemisphere of their brains as the healthy controls. For minimally conscious patients, that number increased to 58%.

Through analysis, the researchers were able to determine that patients below a well-defined threshold of 42% of normal cortical activity were fully unconscious and would not recover within 1 year. Patients above that threshold showed signs of awareness at the initial examination or had recovered responsiveness at the 1 year mark. Using this threshold, the research team was able to predict which patients would regain consciousness with 88% accuracy.

“In nearly all cases, whole-brain energy turnover directly predicted either the current level of awareness or its subsequent recovery,” says Ron Kupers … “In short, our findings indicate that there is a minimal energetic requirement for sustained consciousness to arise after brain injury.”

That minimal energetic requirement will potentially prove useful to doctors trying to advise patients’ families on whether to pursue treatment or withdraw artificial life support. Clinicians can use this PET Scan and threshold calculation to help families understand which patients will recover and which will never wake up from their coma. When patients fall below the threshold, family members will be better informed to decide when it is time to withdraw life-sustaining treatment.

The decision to “pull the plug” on a catastrophically injured family member is heart-breaking. Nothing will make it easy. But by using this test, doctors may be able to provide some certainty to family members and help them to make the right choice.

David Christensen is a brain injury expert at Christensen Law in Southfield, Michigan. He helps the families of TBI patients collect auto insurance benefits after a crash. If your loved one is in a coma, contact Christensen Law for a free consultation to get help with medical expenses.