CT scan not enough. Brain death still requires clinical evaluation
A brainstem CT scan cannot be used as a standalone tool to confirm brain death, according to a study conducted in 15 intensive care units in Canada. Despite its high sensitivity, imaging tests too often report false positives. Experts emphasize that final diagnosis should still be based on a thorough clinical examination.
Brain death is a borderline state – medically, ethically and legally. Its diagnosis determines the end of therapy and often also the initiation of the organ donation procedure. Therefore, each diagnostic method must be as certain as possible. A team of scientists from the University of Montreal checked whether computed tomography of the brain perfusion and CT angiography can be sufficient to pronounce brain death. As it turned out – they cannot.
The study included 282 patients in intensive care units. All underwent a clinical examination at the bedside , including an apnea test, and brain scans —perfusion and angiography—done within two hours of the clinical examination. Imaging was assessed by independent neuroradiologists blinded to the bedside examination results.
The sensitivity of brainstem perfusion tomography was 98.5% , meaning the test accurately detected almost all cases of brain death. But the specificity—the ability to exclude patients who are still alive—was much lower: just 74.4% . That means that one in four patients could be mistakenly declared dead.
Scientists emphasize that even high test sensitivity is not enough if specificity remains too low. False positive results carry serious risks – especially when death is at stake.
Neither CT perfusion nor CT angiography met previously established accuracy criteria of exceeding 98% sensitivity and specificity, concluded the authors of the study published in JAMA Neurology .
Imaging tests, although increasingly refined, cannot completely replace clinical examination . Their role is auxiliary – useful when the result of a clinical examination is ambiguous and the patient's condition prevents a full assessment. This is an important reminder at a time when medicine is eager to reach for technology as a shortcut.
- Brain death lies at a tense intersection of intensive care medicine, ethics, and the logistics of organ donation, the authors write.
And they add that careless decisions can lead to a situation straight out of Edgar Allan Poe's stories - a terrifying mistake between life and death. That's why it's so important that new tools don't overshadow the basics: careful clinical judgment, physician experience and caution in borderline decisions.
Source: medicalxpress.com
Updated: 23/06/2025 19:30
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