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  5. I66
  6. 2024 ICD-10-CM Code I66.0
Version 2024
Non-Billable Code

2024 ICD-10-CM Diagnosis Code I66.0

Occlusion and stenosis of middle cerebral artery

ICD-10-CM Code:
I66.0
ICD-10 Code for:
Occlusion and stenosis of middle cerebral artery
Is Billable?
Not Valid for Submission
Code Navigator:

Code Classification

  • Diseases of the circulatory system
    (I00–I99)
    • Cerebrovascular diseases
      (I60-I69)
      • Occlusion and stenosis of cerebral arteries, not resulting in cerebral infarction
        (I66)

I66.0 is a non-specific and non-billable diagnosis code code, consider using a code with a higher level of specificity for a diagnosis of occlusion and stenosis of middle cerebral artery. The code is not specific and is NOT valid for the year 2024 for the submission of HIPAA-covered transactions. Category or Header define the heading of a category of codes that may be further subdivided by the use of 4th, 5th, 6th or 7th characters.

Specific Coding Applicable to Occlusion and stenosis of middle cerebral artery

Non-specific codes like I66.0 require more digits to indicate the appropriate level of specificity. Consider using any of the following ICD-10-CM codes with a higher level of specificity when coding for occlusion and stenosis of middle cerebral artery:

  • Use I66.01 for Occlusion and stenosis of right middle cerebral artery - BILLABLE CODE

  • Use I66.02 for Occlusion and stenosis of left middle cerebral artery - BILLABLE CODE

  • Use I66.03 for Occlusion and stenosis of bilateral middle cerebral arteries - BILLABLE CODE

  • Use I66.09 for Occlusion and stenosis of unspecified middle cerebral artery - BILLABLE CODE

Index to Diseases and Injuries References

The following annotation back-references for this diagnosis code are found in the injuries and diseases index. The Index to Diseases and Injuries is an alphabetical listing of medical terms, with each term mapped to one or more ICD-10-CM code(s).

Patient Education


Brain Diseases

Your brain is the control center of your body. It controls your thoughts, memory, speech, and movement. It regulates the function of many organs. It's part of your nervous system, which also includes your spinal cord and peripheral nerves. The nervous system sends signals between your brain and the rest of the body. Your nerves take in information from your senses and send it to the brain to be processed. Your brain and nerves also communicate to help you move and to control your body's functions.

When the brain is healthy, it works quickly and automatically. But when you have a brain disease, it may affect how well you can function and do your daily activities. Some common brain diseases include:

  • Brain tumors, which can press on nerves and affect brain function.
  • Degenerative nerve diseases, which can affect many of your body's activities, such as balance, movement, talking, breathing, and heart function. Types include Alzheimer's disease and Parkinson's disease.
  • Encephalitis (inflammation in the brain), which can lead to problems such as vision loss, weakness, and paralysis.
  • Genetic brain disorders, which are caused by changes in genes (also called variants or mutations). These disorders can affect the development and function of the brain.
  • Strokes, which can cause a loss of brain cells and can affect your ability to think clearly.
  • Traumatic brain injuries (TBIs), which can affect brain function. They may range from mild to severe. The effects of a TBI may be temporary or permanent.

The symptoms of brain diseases vary widely, depending on the specific problem. In some cases, damage is permanent. In other cases, treatments such as surgery, medicines, or therapies such as physical, occupational, and speech therapies, may cure the disease or improve the symptoms.


[Learn More in MedlinePlus]

Code History

  • FY 2024 - No Change, effective from 10/1/2023 through 9/30/2024
  • FY 2023 - No Change, effective from 10/1/2022 through 9/30/2023
  • FY 2022 - No Change, effective from 10/1/2021 through 9/30/2022
  • FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016. This was the first year ICD-10-CM was implemented into the HIPAA code set.