What is psychiatric neuroimaging?
Psychiatric neuroimaging is the state-of-the-art and growing field of using modern neuroimaging (brain scans) in order to better understand an individual’s psychiatric condition. Older neuroimaging technology (e.g. SPECT) had little value for psychiatrists to actually help their suffering patients. However, newer diagnostic technologies (such as functional MRI) are adding much more useful data in unraveling the complexity behind psychiatric conditions. And more importantly, modern neuroimaging allows for newer and potentially more powerful treatments (one such example is fMRI-guided TMS).
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Psychiatric neuroimaging does not give a concrete answer or solution to a patient’s condition. Rather, it adds a very useful facet of data for the treatment team: neurologic. It can help to understand an individual’s psychiatric condition from a neurologic perspective: its core biological underpinnings, and how various brain centers (or wiring) may be involved in one’s psychiatric problems.
This may be very helpful in building insight, planning treatment, and ongoing recovery. Psychiatric conditions are complex and can be the result of a combination of many underlying causes. These causes include not only neurological, but also: psychological, personality, social, childhood & developmental, and environmental factors. The neurologic perspective is just one of many possible causes, but a very important one. Until recently, neuroimaging technology was not yet sophisticated enough in order to aid psychiatrists. But now things are changing.
Very few psychiatrists have expertise in neuroimaging. Of the few that do, most are located at university research institutions performing research and not treating patients. Physicians at CNS have been involved in neuroimaging research for over 20 years, including: MRI, fMRI (functional MRI), CT, PET, DTI, and MRS.
Who can benefit?
- Individuals who have been diagnosed with new and concerning psychiatric conditions.
- Patients who have hit roadblocks with traditional treatment or medications.
- Patients and families who are intending to better understand their psychiatric condition from a different, neurologic perspective.
- Patients who wish to map their brain in order to undergo fMRI-guided TMS.
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How is it done?
- Physician orders: The patient has an appointment with their psychiatrist, who then orders the correct set of tests specific for the patient’s symptoms.
- Patient training: Since the functional brain scans are customized for each patient, the patient must undergo a brief training program in order to prepare for the test. Here, the patient learns what to expect during the actual neuroimaging (e.g. they may view certain videos or slideshows and perform certain tasks while in the scan).
- Computer processing: The result is a complex set of data which represents how the patient’s brain responded to the various tests (it is not a simple picture, like for a traditional X-ray or CT scan). The data then undergoes computerized processing and analysis in order to produce meaningful statistics and images. Statistical analysis can be performed where an individual’s specific brain region sizes (or functioning) are compared to hundreds (or thousands) of similarly-aged individuals.
- Reading & interpretation: The neuroimaging clinical team will then discuss the patient, their specific symptoms, analyze their neuroimaging and its data, and make useful observations interpretations. This team is composed of psychiatrists, behavioral neurologists, neuroradiologists, and other neuroimaging experts.
- Report: The team will then use their knowledge in psychiatry, neurology, and recent research studies in order to shed more light on the biological basis of the patient’s psychiatric condition. The patient’s psychiatrist can then use this information in order to modify their treatment plan. One such example if to use the coordinates for fMRI-guided TMS or TBS.
What specific tests are ordered? This will be determined by the ordering psychiatrist and the CNS Neuroimaging Team. It depends on the patient, and their specific set of signs, symptoms and difficulties in life. The following is a list of tests which may be included.
MRI (Magnetic Resonance Imaging):
- Produces clear images of a brain, from numerous slices and numerous angles.
- Brain size and other features can be analyzed visually.
- Computerized analysis can quantitatively show the size of hundreds of individual brain regions.
- Major anatomical abnormalities can be seen, including: masses, tumors, lesions, strokes, or congenital malformations.
- Minor variations can be seen as well, such as atypicalities in an individual’s neuroanatomy, location of important regions, or gyration patterns.
fMRI (Functional MRI):
- Produces images and data on how someone’s brain actually functions.
- Results may shed light on how an individual’s brain processes information – including cognitively as well as emotionally.
- Results can be either typical or atypical.
- Atypical patterns can sometimes be correlated with certain psychiatric conditions. (Link to 2017 fMRI analysis in schizophrenia)
- There are 2 types of fMRI: Resting-state and Stimulated.
Resting fMRI:
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- These are performed when the individual is simply at rest (but not sleeping).
- Results help to understand how an individual’s brain functions when in an average, non-active state.
Stimulated fMRI:
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- Performed while the individual is undergoing certain tasks or tests.
- Specific tasks are chosen by the individual’s doctor and neuroimaging team.
- Computerized analysis produces images of various neural networks, such as those seen in anxiety, depression, or OCD.
- Results can help to understand which neural networks may be involved in a patient’s psychiatric condition.
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DTI (Diffusion Tensor Imaging):
- Produces an image of a patient’s white matter (fiber tracts) – or in other words, the brain’s internal wiring.
- This is contrast to MRI/fMRI, which is a picture of the brain’s grey matter (processing center).
- Is usually helpful in certain neurologic conditions (such as stroke, tumors, or multiple sclerosis).
- Can sometimes be helpful in certain neuropsychiatric conditions (such as traumatic brain injury, concussions, or possibly schizophrenia).
ASL (Arterial Spin Labeling):
- Produces images of how blood perfuses through different regions of the brain.
- Can help reveal if certain regions of the brain are “shut down.”
- Can help reveal if regions are operating in an asymmetric or atypical fashion.
MRS (Magnetic Resonance Spectroscopy):
- Measures the biochemical composition in specific regions of the brain.
- Can compare the neurochemistry of normal brain tissue with abnormal tissue.
- Classically is used to detect tissue changes in stroke and epilepsy.
- Increasingly being used to detect early changes in psychiatric conditions. (Link to article on MRS in pre-schizophrenia – Journal of American Medical Association 2016).
Why aren’t more doctors using psychiatric neuroimaging? Many doctors are beginning to use psychiatric neuroimaging. But for numerous reasons, many are not. These reasons include:
- Training: Psychiatry training does not include education on neuroimaging. As the field continues to grow, one day this will change. Other medical specialties are more familiar with neuroimaging, such as neurologists and neuroradiologists.
- Awareness: Many physicians are simply not yet aware of the rapidly growing body of recent research regarding psychiatric neuroimaging and its helpfulness. As a phsyician, it is challenging to stay updated on current research.
- Technology: Historically, neuroimaging wasn’t very helpful in aiding psychiatrists in the treatment of their patients. Psychiatrists can (and should) be very protective of their patients’ seeking advice from potentially unhelpful sources. Psychiatrists believe in hope, but not in providing a false sense of hope. In past decades, some scientists made overly-enthusiastic promises about psychiatric neuroimaging before it was truly ready. And because of this, many psychiatrists are (rightfully) skeptical of neuroimaging. Luckily, neuroimaging technology has recently rapidly advanced.
- Cost: Many functional neuroimaging studies are not yet covered by insurance companies. This leaves the patient with the burden of paying for the non-trivial cost of neuroimaging. Hopefully, one day this will change. But it can take a long time for insurance companies to begin paying for medical tests and treatments. For example, it took many years for insurance companies to agree to pay for a PET scan in diagnosing Alzheimer’s dementia.
- Access: Many physicians and patients simply do not live in areas which possess the advanced neuroimaging equipment which is necessary for psychiatric neuroimaging.
How new is psychiatric neuroimaging? Psychiatric neuroimaging technology is relatively new and rapidly advancing. Historically, neuroimaging technology wasn’t helpful in treating individual patients (but this is beginning to change). Psychiatric conditions, when neurologic in origin, are disorders of very small neural networks which are not functioning correctly (due to genetic, development, physiologic, electrical, or chemical reasons). They can be very difficult to “see.”
- 1960’s: Early neuroimaging technology (for example, CT scans) were somewhat crude and helpful only in identifying large and obvious medical problems (e.g. brain tumors or emergency bleeds), but not for psychiatric conditions. Tumors can be large and relatively easily seen on CT scans. In contrast, psychiatric conditions generally do not consist of large anatomical abnormalities.
- SPECT scans were also crude. Although some doctors over-promised their usefulness for psychiatric conditions, they are generally helpful in medical conditions such as infection, stroke, dementia, and epilepsy.
- 1980’s: neuroimaging technology continued to advance (e.g. PET scans). It began to be particularly useful in research settings where hundreds (or thousands) of subjects were being analyzed. Subtle patterns in various psychiatric problems slowly started to emerge. However, these patterns weren’t yet detectable on an individual basis – but only in large studies.
- 1990’s: technology made enormous advancements with the development of MRI and fMRI. Although still mainly useful in a research setting when hundreds of images were being compared, more of the biological underpinnings of psychiatric conditions were revealed (such as atrophy – or loss of volume – in certain brain regions such as in dementia or schizophrenia), .
- 2000’s: Explosion in neuroimaging technology (e.g. 3D fMRI, Resting BOLD, DTI, GRE field mapping).
- 2010’s: Scientists began collaborating on national and international levels to build large data sets and software to help in research as well as clinical settings. Examples include the ADNI, Human Connectome, and Freesurfer projects. Many of these projects were founded at UCLA, USC, or Harvard. Similar to the human genome project, for the first time in history, scientists have an abundance of data – but the challenge is figuring out how this data applies to individual patients.
Is this similar to other trendy brain scans (e.g. SPECT neuroimaging)? No. SPECT neuroimaging is a technology which is over 50 years old, and is extremely controversial for helping psychiatric conditions. Most psychiatrists don’t believe that a crude picture of the brain can “tell” a doctor which medication to prescribe. An analogy would be of an X-ray telling a doctor which medication to prescribe for diabetes: it just doesn’t make sense. Diabetes is a problem of glucose receptors, which cannot yet be seen by an image.
In contrast, modern psychiatric neuroimaging combines multiple FDA-approved tools in order to analyze brain structure and function (e.g. MRI, DTI, etc). Whereas SPECT has very little research backing it up, the above tools have an enormous amount of research (including the US National Institute of Health). Our goal isn’t to “tell” the psychiatrist what to prescribe. Rather, our goal is to add additional information to the psychiatrist’s toolkit to aid in understanding why a patient may be having psychiatric difficulties: specifically, from a neurologic & biological perspective. This may help educate the patient and their loved ones and possibly aid the psychiatrist in their treatment planning. One such example of a possible treatment is fMRI-guided TMS (Transcranial Magnetic Stimulation). Psychiatric neuroimaging can help the doctor more precisely localize which brain centers to target with TMS. An analogy would be of a surgeon using an MRI to locate which bones or ligaments on which to operate.
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