Dementia With Lewy Bodies
Dementia with Lewy Bodies is a type of dementia that shares symptoms with both Alzheimers disease and Parkinsons disease. It may account for around 10 per cent of all cases of dementia but tends to be underdiagnosed. Lewy Bodies are tiny deposits of protein in the nerve cells of the brain. Their presence is linked to low levels of dopamine and a loss of connections between cells.
The symptoms a person experiences will depend partly on where the Lewy bodies are in the brain. Lewy bodies in the striata are closely linked to problems with movement. These are the main feature of Parkinsons disease. Lewy bodies in the outer layers of the brain are linked to problems with mental abilities , which are characteristic of Dementia with Lewy Bodies.
Symptoms in Dementia with Lewy Bodies include problems with attention and alertness which fluctuate over the course of the day. Visual hallucinations are also common and can be very distressing. Up to two thirds of people with Dementia with Lewy Bodies have movement problems. These symptoms are those of Parkinsons disease, and include slowness and rigidity of movement with a blank facial expression.
DaTSCANTM can:
- Provide an early diagnosis of Dementia with Lewy Bodies
- Prevent exposure to medications that may aggrevatesympotms or cause severe reactions.
- Identify commonly occurring and treatable disorders .
Am I Convinced That I Have Pd
Three years after my diagnosis, I am still struggling to find relief from my symptoms and slow the progression of this disease. I exercise, eating a mostly vegan and gluten-free diet, take Sinemet , and use the Neupro transdermal patch. I am working with my current neurologist to fine-tune my medication cocktail.
I had wondered whether I did have PD since Ive never had an aha moment in which I feel somewhat normal after taking medications. People tell me I look fine and they dont observe any external signs of the disease. However, my tremors are internal and I feel horrible and constantly fatigued.
What Doctors Look For When Diagnosing Parkinsons
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:
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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
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Bradykinesia: Slowness of movement in the limbs, face, walking or overall body
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Rigidity: Stiffness in the arms, legs or;trunk
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Posture instability: Trouble with balance and possible falls
Once the patient is at the doctors office, the physician:
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Takes a medical history and does a physical examination.
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Asks about current and past medications. Some medications may cause symptoms that mimic Parkinsons disease.
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Performs a neurological examination, testing agility, muscle tone, gait and balance.
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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.
Diagnosis Of Parkinsons Via Datscan And Clinical Exam Are Similarly Accurate
Despite the DaTscan being available to help diagnose Parkinsons, in most clinical situations, a DaTscan will not add information to what can be gleaned from the clinical exam. One study actually demonstrated that the accuracy of diagnosis in early PD was the same whether the diagnosis was reached using clinical exam or using DaTscan.
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Testing For Parkinsons Disease
There is no lab or imaging test that is recommended or definitive for Parkinsons disease. However, in 2011, the U.S. Food and Drug Administration approved an imaging scan called the DaTscan. This technique allows doctors to see detailed pictures of the brains dopamine system.
A DaTscan involves an injection of a small amount of a radioactive drug and a machine called a single-photon emission computed tomography scanner, similar to an MRI.
The drug binds to dopamine transmitters in the brain, showing where in the brain dopaminergic neurons are.
The results of a DaTscan cant show that you have Parkinsons, but they can help your doctor confirm a diagnosis or rule out a Parkinsons mimic.
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What To Expect During A Datscan
Before the DaTscan, it is essential to discuss the patients medical history with the doctor. For instance, some medications may interfere with the imaging and may need to be discontinued.
The radioactive agent that is injected into the patients bloodstream before the imaging takes some time to reach the striatum region of the brain where cells carrying DaT are usually found. After injection, the patient may need to wait for three to six hours before receiving the SPECT scan to visualize DaT distribution in the brain. The scan itself can take 45 minutes to an hour.
The radiologist will then send the brain scans to the neurologist who will explain the results to the patient.
Imaging Studies Can Differentiate Parkinsons From Other Causes Of Parkinsonism
Catherine L. Gallagher, MD
Although Parkinsons disease remains a clinical diagnosis, imaging studies are an important ancillary test for differential diagnosis of movement disorders. Imaging studies may be used to rule out structural and other causes of parkinsonian symptoms. Single-photon emission computed tomography scans using labeled tracers for dopamine transporters can also be used to confirm parkinsonism or differentiate PD from secondary causes of parkinsonian motor symptoms. Finally, imaging studies are being used in research to better understand the pathophysiology of PD and elucidate causative mechanisms that could be therapeutic targets in the future.
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How Do I Prepare For A Pet Scan
Before undergoing the PET procedure, be sure to tell your doctor of any medication — prescription or over-the-counter — that you are taking, as well as any herbal medications you may be using. It is also very important that you tell the doctor if you are pregnant or think you may be pregnant, since the PET scan can be harmful to an unborn child.
As the test is about to begin, you will be asked to take off clothing that is covering the area of the body to be tested. Depending on the area of your body being tested, you may be asked to undress completely and put on a hospital gown. You will also be asked to remove any dentures, jewelry, or metal objects during the scan, since these items may affect the reading.
How Much Does A Functional Mri Cost
How Much Does a Functional MRI Cost? On MDsave, the cost of a Functional MRI ranges from $488 to $542. Those on high deductible health plans or without insurance can save when they buy their procedure upfront through MDsave. Read more about how MDsave works.
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Is A Spect Scan Worth It
SPECT scans can be useful in bone disorders because areas of concern will often light up on the images. The conditions that can be explored using this technology include: Less visible bone fractures, such as stress fractures. Bone cancer or cancer that has metastasized to areas of bone.
Role Of Dat Scan In Early Diagnosis And Management
Sensitivities and specificities of DaT scan use are as follows:
- Differentiating essential tremor from PD sensitivity 93%; specificity 100%
- Differentiating dementia with Lewy bodies from AD or other dementia sensitivity 93%; specificity 86%
In clinically-uncertain Parkinsonian syndrome, 53% accuracy in early diagnosis without the scan versus 86-90% accuracy with the scan has been reported.
In clinically-uncertain Parkinsonian syndrome, 53% accuracy in early diagnosis without the scan versus 86-90% accuracy with the scan has been reported
In general, Dr Tao reported, 50% or more of patients have their clinical management changed following DaT scan changed, depending on whether the technique is being used by a MDS specialist or not. Non-specialists tend to change clinical management strategies in a greater proportion of patients than specialists.
50% or more of patients have their clinical management changed following DaT scan changed
Essential tremor is not difficult to diagnose in most patients but can sometimes be challenging if it is present with symptoms mimicking Parkinsonism.; And, he reminded the audience, patients with a long-standing essential tremor are also more likely to develop PD and, therefore, become ET/PD.
Cases demonstrate value of DaT scan in clinical practice
Dr Tao warned that certain medicines that bind to the dopamine transporter can interfere with diagnosis, including cannabis, and need to be discontinued prior to DaT scan.
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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.
Imaging And Differential Diagnosis
The core clinical signs of PD include resting tremor, bradykinesia, rigidity, and postural instability. Most patients also experience nonmotor symptoms such as cognitive and emotional changes , dysautonomia, sleep disorders, and sensory disturbances. Many experience prodromal nonmotor symptoms such as anosmia, depression, constipation, and REM sleep behavior. Clinical subtypes of the disease have been identified, including tremor dominant and postural instability gait difficulty . Atypical features may be clues that there are other etiologies that can be differentiated with imaging studies.1 Structural brain imaging is frequently ordered to investigate these cases. In addition, SPECT imaging with DaT may be useful to confirm central nervous system dopamine signaling deficiency in select cases . On DaT scans, normal radiotracer uptake in the striatum forms 2 crescent-shaped regions of activity, mirrored around the median plane. In contrast, in PD, there is asymmetrically decreased activity in the putamen, often with preserved uptake in the caudate nucleus.2,3 A DaT scan is FDA approved for differentiating essential tremor from PD, and is also frequently useful for differentiating drug-induced parkinsonism from PD.
Cerebrovascular Disease
Corticobasal Degeneration
Multiple System Atrophy
Progressive Supranuclear Palsy
Neoplasms
Neurotoxicity
Normal Pressure Hydrocephalus
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Data Extraction And Quality Assessment
Data were extracted by two reviewers independently and were recorded in absolute numbers. Where proportions only were reported the absolute figure was recalculated. Data on clinical utility following imaging with DaTscan, scan technical characteristics ), and baseline characteristics of studied patients were extracted . Change in diagnosis was defined as any change in the patients assigned or suspected diagnosis following disclosure of the results of the imaging scan. Change in management was defined as any changes that the study authors recorded as changes in treatment or further investigations, such as drug changes , referral for counselling or physical therapy following the disclosure of DaT imaging results. Results were compared, and discrepancies between the two reviewers were resolved in a meeting.
Risk of bias assessment was carried out on all studies using an adapted form of the QUADAS-2 checklist amended by the study authors to fit studies of clinical utility, rather than diagnostic accuracy. A copy of the amended QUADAS-2 checklist is provided in Supplementary data . The risk of bias assessment was used independently of the quantitative meta-analysis.
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.
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Referral To A Specialist
If your GP suspects Parkinson’s disease, you’ll be referred to a specialist.
This will usually be:
- a neurologist, a specialist in conditions affecting the brain and nervous system
- a geriatrician, a specialist in problems affecting elderly people
The specialist will most likely ask you to perform a number of physical exercises so they can assess whether you have any problems with movement.
A diagnosis of Parkinson’s disease is likely if you have at least 2 of the 3 following symptoms:
- shaking or tremor in a part of your body that usually only occurs at rest
- slowness of movement
- muscle stiffness
If your symptoms improve after taking a medication called levodopa, it’s more likely you have Parkinson’s disease.
Special brain scans, such as a;single photon emission computed tomography scan, may also be carried out in some cases;to try to;rule out;other causes of;your symptoms.
On The Day Of The Exam
- Drink plenty of fluids and go to the bathroom frequently
- Wear loose comfortable clothing, since you will need to lie still for a period of time.
- Please bring a list of all medications that you are taking; name and dosage.
- We want to make your waiting time as pleasant as possible. Consider bringing your favorite magazine, book or music player to help you pass the time.
- Please leave your jewelry and valuables at home.
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Does The Pet Scan Have Risks
Because radiation is part of a PET scan, there is always a small risk that cells or tissue may have received some damage following the procedure. However, the radiation levels from the tracer that is sent throughout the body are very low.
In addition, following the scan, patients may find that their arm is a little bit sore or that they experience redness where the IV was placed in the arm.
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 Should I Get A Datscan Or Pet Scan To Confirm My Diagnosis Of Parkinsons Disease
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
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