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Can A Dat Scan Detect Dementia

What’s Hot In Pd Should I Get A Datscan Or Pet Scan To Confirm My Diagnosis Of Parkinsons Disease

Can a brain scan indicate that someone is susceptible to dementia or Alzheimer’s?

This past month, the FDA approved DaTscan , a radiopharmaceutical agent which is injected into a patients veins in a procedure referred to as SPECT imaging. DaTscan is an important addition because it is anticipated to be more widely available than other techniques and it has received several major endorsements from leading scientists.

One of the most frequently asked questions about Parkinson’s disease on the Parkinson’s Foundation Ask the Doctor forum is whether or not to pursue DaT or PET scanning to confirm a diagnosis of Parkinsons disease. In this months Whats Hot column, we offer a review of the subject in light of the recent FDA approval.

If you have already received a diagnosis from an expert, and are responding well to dopaminergic therapy, in most cases of Parkinsons disease, PET and SPECT scans would not add any new information and therefore likely to be unnecessary. In cases where the expert is not sure of the diagnosis is it essential tremor or Parkinsons, for example– or where a potentially risky procedure is being considered , it is reasonable for your doctor to recommend a PETscan or DaTscan. It is important to keep in mind that PET and SPECT scans should be performed only by experienced neurologists who have executed a large volume of Parkinsons disease scans, because experience is important in accurately reading these imaging results.

Selected References

Images:

What Are The First Signs Of Lewy Body Dementia & Can An Mri Detect Lewy Body Dementia

Lewy body dementia is an advanced brain disorder. The Lewy bodies build-up in portions of the brain which regulate movement, cognition, and behaviour. This disease affects the bodys autonomic body functions, like temperature regulation, blood pressure control, bowel, and bladder function. Lewy body dementia is considered as the second most prevalent kind of progressive dementia that follows Alzheimers disease dementia.

New Diagnostic Standards For Parkinsons

Until recently, the gold-standard checklist for diagnosis came from the U.K.s Parkinsons Disease Society Brain Bank. It was a checklist that doctors followed to determine if the symptoms they saw fit the disease. But thats now considered outdated. Recently, new criteria from the International Parkinson and Movement Disorder Society have come into use. This list reflects the most current understanding of the condition. It allows doctors to reach a more accurate diagnosis so patients can begin treatment at earlier stages.

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How Does The Datscantm Work

The radiopharmaceutical, or tracer, which is used in DaTSCANTMis Iodine-123 Ioflupane. It is injected into the vein after administering a thyroid blocking agent in the form of oral potassium iodide. This is to prevent unnecessary accumulation of the radiopharmaceutical in the thyroid gland.

The DaTSCANTM binds to the presynaptic dopamine transporters in the brain, in particular the striatal region of the brain. In Parkinsons disease and Dementia with Lewy Bodies there is a marked reduction in dopaminergic neurons in the striatal region. The tracer binds to the dopamine transporters and gives a semi-quantitative measure and spatial distribution of the transporters.

The scan itself is a single photon emission computed tomography scan of the brain. The patient lies down on the examination couch with their head positioned in the headrest. Often a gentle head restraint is used to minimise motion. The gamma camera rotates around the patients head for approximately 30-45 minutes. During this time, it is important that the patient lies still as a three-dimensional image of the distribution of the dopamine receptors in the brain is being created.

Most patients will tolerate the scan very well, and we are used to performing the scans in patients with a tremor. In patients with suspected dementia, it is very useful to liaise with a carer to make sure the patient can attend the appointment. It is also reassuring for the patient to have their carer next to them during the scan.

What Doctors Look For When Diagnosing Parkinsons

DaT scan from a patient without Parkinson

Certain physical signs and symptoms noticed by the patient or his or her loved ones are usually what prompt a person to see the doctor. These are the symptoms most often noticed by patients or their families:

  • Shaking or tremor: Called resting tremor, a trembling of a hand or foot that happens when the patient is at rest and typically stops when he or she is active or moving

  • Bradykinesia: Slowness of movement in the limbs, face, walking or overall body

  • Rigidity: Stiffness in the arms, legs or trunk

  • Posture instability: Trouble with balance and possible falls

Once the patient is at the doctors office, the physician:

  • Takes a medical history and does a physical examination.

  • Asks about current and past medications. Some medications may cause symptoms that mimic Parkinsons disease.

  • Performs a neurological examination, testing agility, muscle tone, gait and balance.

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Why Choose Independent Imaging For My Datscan

Independent Imaging has been putting patients first for over 30 years. Our imaging centers in Wellington, Belle Glade, Lake Worth, and Royal Palm Beach, Florida are fully accredited by the American College of Radiology. Our board-certified radiologists are happy to answer any questions you may have, and we offer extended hours six days a week to accommodate our patients and referring physicians.

If you or a loved one would like to schedule a DaTSCAN, or any of the other imaging services we offer, please call today, or submit an appointment request online.

Should I Get A Datscan Or Pet Scan To Confirm My Diagnosis Of Parkinsons Disease

You can find out more about NPFs National Medical Director, Dr. Michael S. Okun, by also visiting the NPF Center of Excellence, University of Florida Center for Movement Disorders & Neurorestoration.

This past month, the FDA approved DaTscan , a radiopharmaceutical agent which is injected into a patients veins in a procedure referred to as SPECT imaging. DaTscan is an important addition because it is anticipated to be more widely available than other techniques and it has received several major endorsements from leading scientists.

One of the most frequently asked questions about Parkinsons disease on NPFs Ask the Doctor web-based forum is whether or not to pursue DaT or PET scanning to confirm a diagnosis of Parkinsons disease. In this months Whats Hot column, we offer a review of the subject in light of the recent FDA approval.

The new DaT scans use a substance that tags a part of a neuron in the brain where dopamine attaches to it, showing the density of healthy dopamine neurons. Thus, the more of the picture that lights up, the more surviving brain cells. If the parts of the brain where dopamine cells should be remain dark in the scan, an expert reader may diagnose early brain degeneration. This could mean either Parkinsons disease or parkinsonism.

An example DaTscan is shown below and it demonstrates essential tremor on the left , and a parkinsonian syndrome on the right .

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Outlook For Dementia With Lewy Bodies

How quickly dementia with Lewy bodies gets worse varies from person to person.

Home-based help will usually be needed, and some people will eventually need care in a nursing home.

The average survival time after diagnosis is similar to that of Alzheimer’s disease around 6 to 12 years. But this is highly variable and some people live much longer than this.

If you or a loved one has been diagnosed with dementia, remember that you’re not alone. The NHS and social services, as well as voluntary organisations, can provide advice and support for you and your family.

How A Diagnosis Is Made

How to get a diagnosis of dementia?

The bedside examination by a neurologist remains the first and most important diagnostic tool for Parkinsons disease . Researchers are working to develop a standard biological marker such as a blood test or an imaging scan that is sensitive and specific for Parkinsons disease.

A neurologist will make the diagnosis based on:

  • A detailed history of symptoms, medical problems, current and past medications. Certain medical conditions, as well as some medications, can cause symptoms similar to Parkinsons.
  • A detailed neurological examination during which a neurologist will ask you to perform tasks to assess the agility of arms and legs, muscle tone, gait and balance, to see if:
  • Expression and speech are animated.
  • Tremor can be observed in your extremities at rest or in action.
  • There is stiffness in extremities or neck.
  • You can maintain your balance and examine your posture.
  • You may notice that a neurologist records your exam into a table, called Unified Parkinsons Disease Rating Scale . This is a universal scale used by neurologists and movement disorder specialists to comprehensively assess and document the exam of a person with PD at a baseline, judge the effect of medication and track the progression of disease during future visits.
  • Most commonly, people with PD respond well to dopaminergic medications. Lack of response to medications may prompt the doctor to seek an alternative diagnosis such as atypical parkinsonism and order further testing such as an MRI of the brain.
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    Comparison Between Dlb And Pdd

    Attempts to compare GM loss between DLB and PDD have revealed a pattern of more pronounced GM loss in DLB compared to PDD, which is in line with the fact that DLB encompasses greater amyloid burden . It is important to note, however, that localisations of GM reductions in DLB relative to PDD vary amongst different studies. For example, Burton et al. were unable to identify distinct cortical atrophy profiles of DLB and PDD , but Beyer et al. reported GM reductions in the temporal, parietal and occipital lobes in DLB using a voxel-based morphometry approach . Alongside the temporal and parietal atrophy, Lee et al. also reported occipital and striatal GM reductions in DLB . Studies investigating correlation patterns between brain structure and clinical and neuropsychiatric manifestations of the disease, revealed that decreased GM volume of the anterior cingulate, right hippocampus and amygdala were associated with cognitive performance , whilst reduced GM volume in the left precuneus and inferior frontal lobe correlated with visual hallucinations in DLB, but not in PDD .

    Brain Imaging: What Does It See In Dlb

    24 Dec 2015

    At the International Dementia with Lewy Body Conference, held December 1-4 in Fort Lauderdale, Florida, brain imaging emerged as a promising adjunct to figuring out exactly what is going on in a patients brain during life. Given that the clinical diagnosis often misses DLB , and the pathological confirmation comes too late to help the patient, researchers are exploring imaging techniques to bridge this gap. This has created an increasingly varied research field.

    MRI has been around the longest, but appears to be the least powerful in DLB. Showing MRIs from autopsy-confirmed cases, John OBrien of Newcastle University, U.K., confirmed the general finding that the hippocampus in DLB does not shrink much. This finding has become part of the consensus diagnostic criteria. Because it is visible even on CT scans, which are widely available in routine clinical care, this finding is often used to support a diagnosis. And yet, it is not true in all cases, for example those with abundant tau pathology in the hippocampus . In addition, OBrien noted more recent research findings that some cases of clinical DLB do have measurable atrophy elsewhere in the brain. This takes the form of subtle thinning in the insula area of the cortex, as well as in basal ganglia and other subcortical regions. Serial imaging in research studies suggests that this ongoing atrophy is related to concurrent Alzheimers pathology, OBrien said.

    Better Than the Clinician?

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    Low Dopamine Transporter Uptake In Basal Ganglia Demonstrated By Spect Or Pet

    Low dopamine transporter uptake in the basal ganglia, measured with I-FP-CIT SPECT imaging or fluorodopa PET, is clinically useful in distinguishing DLB from AD. A retrospective study showed that DaTSCAN findings were concordant with the outcome clinical DLB diagnosis in 95% cases. A systematic meta-analysis of published studies on DLB diagnostic accuracy of presynaptic dopaminergic imaging with DaTSCAN revealed 86.5% sensitivity and 93.6% specificity differentiating DLB from non-DLB.

    What Are The Limitations Of The Test

    Lewy

    Currently, DaTscan that is in clinical use is not quantitative, which means that the test is not designed to determine how impaired the dopamine system is just whether it is or not. This means that the test is not used to tell you whether the disease has progressed over time and is not used to follow a patients disease. It also is not used currently as a clinical test to screen for the disease before motor symptoms are evident. Because of these limitations, the search continues for additional measurable indicators, known as biomarkers, to help diagnosis and manage PD.

    Tips and Takeaways

    • DaTscan is a test that can help in the diagnosis of PD, although in most situations a clinical exam done by a neurologist offers the same information.
    • Neurologists are skilled to diagnose PD through a clinical exam. While the exam to some may seem very basic and thus a PD diagnosis subjective or questionable, neurologists are well-trained to assess and diagnose with confidence.
    • DaTscan may be useful in distinguishing PD from certain conditions, but not from others, so talk with your neurologist about whether DaTscan would be useful in your specific situation.
    • DaTscan is not a test used for monitoring PD progression. It can be used to help clarify a PD diagnosis, but it is not a test you would undergo multiple times during the course of your disease.

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    Dr. Rebecca Gilbert

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    What Happens During A Datscan

    During a DaTSCAN, a very small amount of tracer, specific for the organ or tissue to be scanned, is injected into a vein by a nuclear medicine technologist. Images may be taken during the injection, immediately after the injection, or following a delayed period to allow the tracer to distribute to the organ or tissue of interest. The gamma rays emitted by the tracer are detected by a special camera that is positioned near the organ or part of the body being imaged.

    You will need to remain very still for the camera, but it will not touch you. The radiation from a nuclear medicine procedure is comparable to that received during a routine X-ray. The tracer only remains in the body for a short period of time before being eliminated in the urine or stool.

    Who Is Datscan For

    DaTscan is not necessary for every Parkinsons patient. For most, the distinct clinical symptoms such as slowness of movement, tremors, and stiffness are sufficient to reach a diagnosis, and the information generated through the scan may not be new and will not alter their treatment plans.

    However, in patients with unclear symptoms that overlap with other neurological conditions and for those who do not respond to treatment, DaTscan can be necessary to reach a diagnosis.

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    What’s Hot In Pd An Update On Dat Scanning For Parkinsons Disease Diagnosis

    In 2011, the FDA approved a diagnostic test for Parkinsons disease. The DaTscan is a radiopharmaceutical agent which is injected into a patients veins in a procedure referred to as SPECT imaging. DaTscan, when it was approved, was considered an important addition to the armamentarium of the bedside clinician. In 2011 I wrote a Whats Hot column on DAT scanning, and this month I will update that posting and bring everyone up to date on the impact of this test.

    One of the most frequently asked questions about Parkinsons disease on NPFs Ask the Doctor web-based forum is whether or not to pursue DaT or PET scan to confirm a diagnosis of Parkinsons disease. The short answer is that the DaT test is over-used in clinical practice, and is only FDA approved to distinguish potential Parkinsons disease from essential tremor. In fact, the test only tells the clinician if there is an abnormality in the dopamine transporter, and does not actually diagnose Parkinsons disease . PET is also overused, though it can be a more powerful diagnostic tool when in the right expert hands.

    The new DaT scans use a substance that “tags” a part of a neuron in the brain where dopamine attaches to it, thus showing the density of healthy dopamine neurons. Thus, the more of the picture that “lights up”, the more surviving brain cells. Dark areas could mean either Parkinsons disease or parkinsonism.

    Selected References

    Why Would My Doctor Order A Datscan

    What is dementia with Lewy bodies?

    Your doctor may order a DaTSCAN to confirm or rule out a diagnosis, or to see how a medication is affecting your brain or internal organs. SPECT scans may also be ordered to help diagnose or monitor conditions affecting the bones and the internal organs, especially the heart and the brain, and even to manage and stage cancer.

    DaTSCAN allows physicians to see which areas of the brain are responding to various stimuli, making it particularly helpful in confirming diagnoses as movement disorders such as Parkinsons Disease, Parkinsonian Syndrome, and Essential Tremor. DaTSCAN can also be helpful in diagnosing and treating traumatic brain injury , attention deficit disorder , attention deficit hyperactivity disorder , and more.

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    Tests For Dementia With Lewy Bodies

    There’s no single test for dementia with Lewy bodies.

    The following may be needed to make a diagnosis:

    • an assessment of symptoms for example, whether there are typical symptoms of dementia with Lewy bodies
    • an assessment of mental abilities this will usually involve a number of tasks and questions
    • blood tests to rule out conditions with similar symptoms
    • brain scans, such as an MRI scan, CT scan or a SPECT scan these can detect signs of dementia or other problems with the brain

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