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PubMed This is a summary of 5 peer-reviewed journal articles Updated
Neurology · Multiple System Atrophy - Parkinsonian type

The Diagnostic Toolkit: Criteria, Imaging, and Tests for MSA-P

At a Glance

Diagnosing Multiple System Atrophy-Parkinsonian type (MSA-P) involves identifying specific motor symptoms, severe autonomic failure, and key MRI markers like putaminal atrophy. A poor or short-lived response to the medication levodopa is also a major clue distinguishing MSA-P from Parkinson's.

Diagnosing Multiple System Atrophy - Parkinsonian type (MSA-P) is a process of assembling a complex puzzle. Because its early symptoms so closely mimic Parkinson’s disease, doctors use a specific set of rules and imaging markers to confirm the diagnosis. Understanding these “rules of the game” can help you audit your own diagnostic journey and have more productive conversations with your care team.

The 2022 MDS Diagnostic Criteria

In 2022, the Movement Disorder Society (MDS) updated the guidelines for diagnosing MSA. These criteria are designed to help doctors identify the disease earlier and with more confidence [1].

  • Clinically Established MSA: This is the highest level of certainty. It requires specific combinations of motor symptoms (like stiffness and slowness), severe autonomic failure (like a major drop in standing blood pressure), and “brain-marker” proof from an MRI or other specialized scans [1].
  • Clinically Probable MSA: This means the diagnosis is very likely but may lack some of the specific “brain-markers” or the extreme severity of autonomic failure required for the “Established” category [1].

One of the biggest clues for doctors is a poor levodopa response. While standard Parkinson’s disease typically responds dramatically to levodopa for many years, only about half of MSA-P patients see an improvement, and that benefit usually fades quickly—often within 3.5 years [1].

Decoding Your MRI Report

When a specialist looks at an MRI for MSA-P, they are looking for specific “signatures” of the disease. Here are the technical terms you might see on your report:

Term What It Means Why It Matters in MSA-P
Putaminal Atrophy Shrinking of the putamen, a brain region that controls movement [2]. This is a hallmark of MSA-P and helps distinguish it from Parkinson’s [1].
T2* Hypointensity “Dark” spots on specific types of MRI scans [3]. This often indicates an abnormal buildup of iron in the brain tissue [1].
Putaminal Rim A bright, thin line or “halo” around the edge of the putamen [2]. This is a “red flag” marker that suggests the support cells in that area are damaged [1].
‘Hot Cross Bun’ Sign A bright, cross-shaped pattern in the pons (part of the brainstem) [1]. While more common in the cerebellar type (MSA-C), it can sometimes appear in MSA-P as the disease progresses [1].

Specialized Diagnostic Tests

Beyond imaging, your doctors may use functional tests to see how your “automatic” systems are working.

  • Urodynamic Testing: This evaluates how well your bladder holds and releases urine. A key “red flag” for MSA is a high post-void residual (PVR) volume—meaning more than 100 mL of urine remains in the bladder after you try to empty it [1][4].
  • Autonomic Testing: This may include a “tilt-table test” to measure how your blood pressure and heart rate react when you are moved from lying down to standing up. A drop of 20 mmHg or more in systolic blood pressure, or a 10 mmHg drop in diastolic blood pressure, within three minutes of standing is a significant diagnostic indicator [1][5].

Common questions in this guide

What are the diagnostic criteria for MSA-P?
The 2022 Movement Disorder Society criteria classify MSA-P as 'Clinically Established' or 'Clinically Probable.' These classifications depend on specific combinations of motor symptoms, the severity of autonomic failure, and specific brain MRI markers.
What does an MRI show for someone with MSA-P?
An MRI for MSA-P often shows putaminal atrophy, which is the shrinking of a brain region that controls movement. Your report might also mention a 'putaminal rim,' signs of iron buildup, or sometimes a 'hot cross bun' sign.
Why do doctors look at my response to levodopa to diagnose MSA-P?
Unlike typical Parkinson's disease, which responds well to levodopa, only about half of patients with MSA-P see improvement. When improvement does happen, it usually fades quickly, helping doctors distinguish between the two conditions.
What is urodynamic testing and why is it used for MSA-P?
Urodynamic testing checks how well your bladder holds and releases urine. A key warning sign for MSA-P is a high post-void residual volume, meaning a large amount of urine stays in your bladder after you try to empty it.
How do doctors test for autonomic failure?
Doctors often use a tilt-table test to measure how your heart rate and blood pressure react when you are moved from a lying to a standing position. A significant drop in blood pressure within three minutes of standing is a strong indicator of MSA.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.Based on the 2022 MDS criteria, is my diagnosis considered 'Clinically Established' or 'Clinically Probable'?
  2. 2.Did my MRI show specific signs of putaminal atrophy or T2* hypointensity that are typical for MSA-P?
  3. 3.Was my post-void residual (PVR) volume high enough to be considered a 'red flag' for MSA?
  4. 4.How would you describe my response to levodopa so far, and how does that affect my diagnosis?
  5. 5.Are there other conditions we are still ruling out, such as Progressive Supranuclear Palsy (PSP)?

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References

References (5)
  1. 1

    The Movement Disorder Society Criteria for the Diagnosis of Multiple System Atrophy.

    Wenning GK, Stankovic I, Vignatelli L, et al.

    Movement disorders : official journal of the Movement Disorder Society 2022; (37(6)):1131-1148 doi:10.1002/mds.29005.

    PMID: 35445419
  2. 2

    A distinct neuromelanin magnetic resonance imaging pattern in parkinsonian multiple system atrophy.

    Simões RM, Castro Caldas A, Grilo J, et al.

    BMC neurology 2020; (20(1)):432 doi:10.1186/s12883-020-02007-5.

    PMID: 33243166
  3. 3

    Differentiation between Parkinson's Disease and the Parkinsonian Subtype of Multiple System Atrophy Using the Magnetic Resonance T1w/T2w Ratio in the Middle Cerebellar Peduncle.

    Wang J, Sugiyama A, Yokota H, et al.

    Diagnostics (Basel, Switzerland) 2024; (14(2)) doi:10.3390/diagnostics14020201.

    PMID: 38248077
  4. 4

    Urodynamic Evaluation in Multiple System Atrophy: A Retrospective Cohort Study.

    Eschlböck S, Kiss G, Krismer F, et al.

    Movement disorders clinical practice 2021; (8(7)):1052-1060 doi:10.1002/mdc3.13307.

    PMID: 34631941
  5. 5

    Is There a Difference in Autonomic Dysfunction Between Multiple System Atrophy Subtypes?

    Garg D, Srivastava AK, Jaryal AK, et al.

    Movement disorders clinical practice 2020; (7(4)):405-412 doi:10.1002/mdc3.12936.

    PMID: 32373657

This information about MSA-P diagnostic criteria and testing is for educational purposes only. Always discuss your specific test results, MRI reports, and symptoms with your neurologist or movement disorder specialist.

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