From the June 2017 issue of HealthCare Business News magazine

There are two general classes of NN exams, separated by the type of physiologic process measured, what I call basal and specific physiology. Basal physiology refers to those processes which all cells of the body engage in. All cells require intermediary metabolism in order to generate stored energy. All cells need blood perfusion for the delivery of nutrients and for the elimination of waste products. Specific physiology refers to processes which are not ubiquitous, but rather are specific to certain types of cells. There are different arrays of NN exams for different disorders. These will now be briefly reviewed.

The remarkable prevalence of dementia and cognitive impairment in the older population is creating a public health epidemic for the aging U.S. population. Dementia is a syndrome and has a wide differential diagnosis. Dementia is also the result of chronic illness. Early diagnosis improves management outcomes. Each disorder which causes dementia has its own basal physiology pattern. Thus, basal physiology imaging with cerebral perfusion SPECT (CPS) and glucose metabolism PET (FDG-PET) can have major roles. In addition, the diagnosis of Alzheimer’s disease can be aided by PET amyloid imaging, of which there are now four FDA-approved radiopharmaceuticals. The exact diagnosis of dementia is important in that drugs which are currently used in cognitively impaired patients can have adverse effects if given to the wrong patient. For instance, neuroleptics given to dementia with Lewy bodies patients or acetylcholinesterase inhibitors given to frontotemporal lobar degeneration patients can cause clinical destabilization.


Grading of brain tumors for degree of malignancy guides therapy which is offered to patients. Grading is performed with FDG-PET and slightly less effectively with thallium-SPECT. Although MRI is highly sensitive for pathology, it has poor specificity and many times cannot distinguish between tumor recurrence or treatment effect. This is the main indication for FDG-PET in brain tumors.

Epilepsy affects 1 percent of the population. It is often unclear what the underlying disorder is in patients presenting with episodic neurologic syndromes. There can be changes in the epileptic brain even when patients are seizure-free, or interictally. This can help distinguish epilepsy from transient ischemic attack or other manifestation of cerebrovascular disease and even somatization psychiatric illness. Many epilepsies can also be cured by surgically resecting the seizure focus. CPS during a seizure (ictus) is a standard diagnostic method of epilepsy centers throughout the world.

June 2017 Magazine

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