ICD-10-CM category
I66 Occlusion and stenosis of cerebral arteries, not resulting in cerebral infarction
I66 is a category, not a billable code. Report one of the 15 complete codes below.
Codes in I66
- I66.01Occlusion and stenosis of right middle cerebral artery
- I66.02Occlusion and stenosis of left middle cerebral artery
- I66.03Occlusion and stenosis of bilateral middle cerebral arteries
- I66.09Occlusion and stenosis of unspecified middle cerebral artery
- I66.11Occlusion and stenosis of right anterior cerebral artery
- I66.12Occlusion and stenosis of left anterior cerebral artery
- I66.13Occlusion and stenosis of bilateral anterior cerebral arteries
- I66.19Occlusion and stenosis of unspecified anterior cerebral artery
- I66.21Occlusion and stenosis of right posterior cerebral artery
- I66.22Occlusion and stenosis of left posterior cerebral artery
- I66.23Occlusion and stenosis of bilateral posterior cerebral arteries
- I66.29Occlusion and stenosis of unspecified posterior cerebral artery
- I66.3Occlusion and stenosis of cerebellar arteries
- I66.8Occlusion and stenosis of other cerebral arteries
- I66.9Occlusion and stenosis of unspecified cerebral artery
Outside the US? I66 in the international WHO ICD-10 lists its inclusion and exclusion notes.
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ICD-10-CM is developed by the National Center for Health Statistics (NCHS), Centers for Disease Control and Prevention, U.S. Department of Health and Human Services, and is based on the WHO ICD-10. Codes and titles are reproduced unchanged from the FY2026 code list (effective 1 October 2025). Their use here does not imply endorsement by CDC, HHS or the U.S. Government. Changes effective on or after 1 October 2026 may not be reflected yet; check the current release at cdc.gov or cms.gov before submitting claims.
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