Every year, nearly 8 million new cases of dementia are diagnosed worldwide, according to the World Health Organization. Diagnosis of Alzheimer’s disease is made in 60 to 80% of these cases, yet when post-mortem brain evaluations are made, around 20 to 30% of these Alzheimer’s diagnoses are found to be incorrect. More accurate diagnosis tools are urgently needed.
Positron emission tomography (PET) is a medical imaging modality that uses radioactive tracer materials and special imaging equipment to evaluate the function of tissue and organs. PET allows radiologists to identify bodily changes taking place at the cellular level, including, for example, increased glucose metabolism in cancerous tumors. Researchers have found promising preliminary results for a new type of PET imaging for Alzheimer’s, though other imaging methods remain the current clinical standard for doing so.
Currently Used Medical Imaging Modalities for Diagnosing Alzheimer’s
Neuroimaging in suspected cases of Alzheimer’s disease currently looks for nonspecific brain features, like atrophy, but atrophy is a late feature of the disease. Magnetic resonance imaging (MRI) is the preferred type of imaging in these cases, because it allows for accurate brain volume calculations, including the size of the hippocampus and other structures.
MRI and computed tomography (CT) imaging are used not so much for diagnosing Alzheimer’s disease as for excluding reversible causes of dementia, like brain tumors and other causes of dementia, such as stroke. But there are some indicators of cognitive diseases like Alzheimer’s on imaging studies. For example, atrophy of the temporal lobe is more predictive of cognitive decline than it is of small-vessel disease in the brain. But so far there’s not a singular imaging modality that reliably indicates Alzheimer’s disease.
Florbetaben PET as a Negative Indicator for Alzheimer’s
A type of PET imaging called Florbetaben PET is a new type of imaging study that may be valuable as a negative indicator for Alzheimer’s. In other words, a negative Florbetaben test appears to reliably indicate the absence of the kind of brain plaques that would indicate Alzheimer’s. While this isn’t a test that can say, “Yes, this person has Alzheimer’s,” it may be able to say with confidence, “No, this person does not have Alzheimer’s,” which is an improvement over typical imaging capabilities used today.
A recent study compared this type of PET imaging with post-mortem histopathology in patients who had undergone florbetaben PET and then agreed to donate their brains to science. Seventy-four brains were evaluated, and researchers found that florbetaban PET allowed for reliable detection and exclusion of amyloid pathology associated with Alzheimer’s disease. Existing diagnosis tools for Alzheimer’s are not that accurate, so the ability to rule out the disease offers more clarity for doctors.
Other Potential Uses for This Type of PET Imaging
Florbetaben PET may have other diagnostic uses as well. PET can be used throughout the body, and this particular method could be used to detect plaques in muscles that indicate a condition called inclusion body myositis. Amyloid plaque formation in muscles appears to follow the same mechanism as it does in the brain, and precursor proteins can be observed in muscles as well. Other tracers are also being studied, so radiologists could potentially have new diagnostic tools available in coming years to help make Alzheimer’s disease diagnosis more accurate and specific than it is currently.
Neuroimaging Is Just One Part of Diagnosing Alzheimer’s Disease
Neuroradiology specialists like Carl Raboi, MD and Richard Spira, MD of SteleRAD play an essential role in diagnosing the causes of dementia and other neurological symptoms. By staying informed on the latest techniques and research, all of SteleRAD’s Board-certified owner-operators are able to offer unmatched expertise throughout South Florida. If your hospital, imaging center, or medical practice could benefit from the outstanding services offered by the radiologists of SteleRAD, we encourage you to call 954-358-5250 or contact us online at any time.