Parkinson’s Disease: Symptoms, Causes, Types & PET CT as a Diagnostic Tool

Parkinson's disease is a degenerative neurological disorder that mainly impacts movement. It is caused by a failure of the brain to maintain nerve cells or by the nerve cells, resulting in impaired bodily and movement functions. Symptoms include shakiness, stiffness, decreased mobility, balance problems, or walking problems.

Parkinson's disease generally occurs later in life; however, there is a wide age range of people with Parkinson's. Symptoms are most often mild in early cases and may mimic the symptoms of other movement disorders. In this regard, detailed medical and neurological evaluation is important. The clinical evaluation may be supplemented with imaging and other tests to further exclude other potential causes of symptoms.

What Is Parkinson’s Disease?

Parkinson's disease is a long-term and progressive condition of the nerves. It mainly affects areas of the brain involved in controlling movement. This can disrupt the brain's smooth and controlled movements. The symptoms of Parkinson's may start gradually. The person might first experience a tremor in one hand and become stiff, slow, or have altered movements when walking. As the disorder worsens, the symptoms with a change in movement may increase. Non-motor symptoms are other symptoms associated with Parkinson's disease. These can include insomnia, constipation, mood changes, fatigue, communication or cognitive issues/dysexecutive functioning.

What Causes Parkinson’s Disease?

There are no known causes of Parkinson's disease. The disease may be caused by a combination of genes and environmental factors. In Parkinson's, nerve cells have been lost or damaged, which reduces the chemical messengers called dopamine, which are important for controlling movement. Low levels of dopamine contribute to numerous movement symptoms that are common in Parkinson's. Genetic mutations might make certain individuals more susceptible to developing Parkinson's. In some cases, environmental exposures may be a factor as well. But it doesn't mean that someone who has a specific risk factor will necessarily get Parkinson's disease.

Symptoms of Parkinson’s Disease

Parkinson's symptoms can be different for each person. These tend to be slowly progressive and can be confined to one side of the body from the outset.

Tremor

One of the most well-known symptoms of Parkinson's disease is a tremor. It can occur in the hand, fingers, or elsewhere in the body and may be more obvious when the affected arm or leg is not moving.

Slow Movement

Everyday tasks may take longer because of Bradykinesia (slowness of movement). Getting up out of a chair, walking around, and tasks demanding fine movements may be hard for an individual.

Muscle Stiffness

Stiffness may be in the arms, legs, neck, or other parts of the body. May cause some discomfort and increase mobility difficulties.

Balance and Walking Problems

As the disease advances, some individuals may experience a postural change, loss of balance, and difficulty with walking. Steps could shorten; difficulty turning and walking may increase.

Other Symptoms

There may be symptoms without a motor component. This can include symptoms such as sleep disturbances, constipation, fatigue, speech changes, depression, anxiety, and cognitive changes. Not everyone with Parkinson’s disease experiences the same combination or severity of symptoms.

Types of Parkinsonism and Parkinson’s Disease

Parkinsonism is a collection of disorders that produce symptoms of movement problems like those common in Parkinson's disease. Other diseases can have symptoms similar to Parkinson's disease, but the most common is Parkinson's.

Idiopathic Parkinson’s Disease

If there is no specific cause, Parkinson's disease is considered idiopathic or Parkinson's with no known cause. It's the most common variety of Parkinsonism more than any other.

Genetic Parkinson’s Disease

Some Parkinson's diseases can be linked to changes in genes that are passed on in families. Genetic forms can be passed on from one generation to the next, and sometimes start at a younger age.

Secondary Parkinsonism

Secondary parkinsonism may be due to another disorder, certain medications, toxins, or brain trauma. It is important to know the underlying cause, as treatment may vary.

Atypical Parkinsonian Disorders

Several neurodegenerative diseases can cause Parkinson-like symptoms, such as multiple system atrophy, progressive supranuclear palsy, and corticobasal degeneration. Certain symptoms, besides the primary symptoms of the disorder, can help doctors differentiate them from the normal Parkinson's.

How Is Parkinson’s Disease Diagnosed?

No single test to confirm Parkinson's disease on its own can be used. The primary diagnosis is made using the patient's history, symptoms, and neurological exam. To rule out other factors that can cause similar symptoms, blood or lab tests and/or brain imaging may be performed. In the neurological examination, a physician may look for normal neurological development, including movement, muscle strength, coordination, reflexes, how you walk, balance, and other neurological functions. As there are multiple movement disorders that may exhibit similar clinical features, detailed clinical assessment is important to ensure a correct diagnosis.

Tests for Parkinson’s Disease

Depending on the patient's symptoms, doctors may recommend different investigations.

Neurological Examination

One of the most important components of Parkinson's disease evaluation is a neurological examination. The doctor evaluates movement, tremor, muscle stiffness, balance and coordination, and other neurological signs.

Blood and Laboratory Tests

There is no standard blood test that is useful for the diagnosis of Parkinson's disease. Other tests of the blood, however, may be ordered in an effort to exclude other conditions which may have similar symptoms.

MRI Brain

MRI may be used to examine the brain and look for structural abnormalities or other conditions that could produce Parkinson-like symptoms. A conventional MRI may appear normal in people with Parkinson’s disease, so it cannot independently confirm the diagnosis.

PET Imaging

PET imaging is a functional imaging technique that can provide information about brain metabolism and biochemical activity. Different radiotracers can be used to study different processes in the brain. PET is increasingly important in neurological research and can provide information that may complement clinical findings.

Role of PET CT in Parkinson’s Disease

PET-CT combines PET imaging, which provides functional or molecular information, with CT imaging, which provides anatomical information. PET uses a radiotracer that accumulates in specific tissues or participates in particular biological processes. The PET component can therefore provide information about brain function, while CT helps with anatomical localization. In movement disorders, functional and neurochemical PET imaging can provide information about brain metabolism and chemistry. This may be useful in selected patients when the clinical diagnosis is uncertain or when doctors need additional information to distinguish between different neurological conditions.

However, PET-CT should not be considered a standalone test that confirms Parkinson’s disease in every patient. The diagnosis remains primarily clinical, and imaging findings must be interpreted alongside symptoms, neurological examination, and medical history. Research is also continuing into PET tracers that can target specific biological changes associated with Parkinson’s disease. NINDS research recommendations highlight the development of PET imaging agents for studying alpha-synuclein and other disease-related processes.

How Does a PET CT Scan Work?

For a PET-CT examination, a radiotracer is generally administered through an intravenous injection. The tracer is allowed time to travel through the body and accumulate in the area being evaluated. The patient then lies on the PET-CT scanner while images are acquired. The PET component detects signals from the radiotracer, while the CT component provides anatomical information. The combined images can help specialists understand functional changes in relation to the underlying anatomy. The exact tracer, preparation, and imaging protocol depend on the clinical purpose of the examination.

Is PET CT Safe?

PET-CT is generally considered safe when appropriately recommended. Nuclear medicine examinations use a small amount of radiotracer, and the radiation exposure is considered acceptable for medically indicated diagnostic examinations. Patients should inform the medical team if they are pregnant, may be pregnant, or are breastfeeding. They should also provide information about their medications, allergies, medical conditions, and recent illnesses. Preparation requirements vary according to the type of PET examination.

Why Is Early Evaluation Important?

Parkinson’s disease is progressive, and symptoms can change over time. Early medical evaluation can help identify the cause of movement-related symptoms and distinguish Parkinson’s disease from other neurological disorders with similar features. A timely evaluation can also help doctors develop an appropriate management and follow-up plan. Depending on the patient's symptoms, the evaluation may involve neurological examination, laboratory testing, MRI, PET, or other investigations.

PET CT for Parkinson’s Disease at Molecular Diagnostics and Therapy

At Molecular Diagnostics and Therapy, advanced nuclear medicine and diagnostic imaging services are available to support the evaluation of neurological and other medical conditions. When PET-CT is recommended by a treating physician, the appropriate imaging protocol and radiotracer can be selected according to the clinical requirement. The scan findings should always be interpreted together with the patient's symptoms, neurological examination, and other relevant investigations.

Conclusion

Parkinson's is a progressive disease of the nervous system that can lead to a variety of non-motor symptoms as well as muscle stiffness, tremors, slow movement, and imbalance. While the exact cause is unknown, thought to be due to genetic and environmental factors. There are no single markers that can be used to diagnose Parkinson's disease on their own. The diagnosis is mostly based on clinical history and neurological examination, with laboratory testing and brain imaging tests used to exclude other possible causes and/or add useful information.

PET-CT may become a valuable tool in some movement disorders studies and in neurological research in selected cases for obtaining functional and anatomical information about the brain. PET-CT results must be evaluated by experts as well as clinical signs and symptoms, and not as a single diagnostic procedure. Molecular Diagnostics and Therapy offers highly sophisticated diagnostic and nuclear medicine services to assist physicians in the assessment of complicated neurological problems and in decision-making.