I66
ICD-10Non-billable categoryOccls and stenosis of cereb art, not rslt in cerebral infrc
Official ICD-10-CM descriptor (FY2026)
Occlusion and stenosis of cerebral arteries, not resulting in cerebral infarction
I66 is a category heading, not a billable code. CMS does not accept it on a claim; report one of the more specific codes beneath it.
Includes
- embolism of cerebral artery
- narrowing of cerebral artery
- obstruction (complete) (partial) of cerebral artery
- thrombosis of cerebral artery
Excludes1
Not coded here. An Excludes1 code should never be reported at the same time as the code above it.
- Occlusion and stenosis of cerebral artery causing cerebral infarction (I63.3-I63.5)
More specific codes under I66
- I66.0Occlusion and stenosis of middle cerebral arterycategory
- I66.1Occlusion and stenosis of anterior cerebral arterycategory
- I66.2Occlusion and stenosis of posterior cerebral arterycategory
- I66.3Occlusion and stenosis of cerebellar arteries
- I66.8Occlusion and stenosis of other cerebral arteries
- I66.9Occlusion and stenosis of unspecified cerebral artery
Where this code sits
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ICD-10-CM FY2026. Centers for Medicare & Medicaid Services (CMS) / National Center for Health Statistics (NCHS), “2026 ICD-10-CM Code Descriptions in Tabular Order” (icd10cm_order_2026.txt). Download the original file from cms.gov. Public domain (US Government work). Descriptors, billable flags and instructional notes on this page are reproduced from that file without modification. Krasyn adds no clinical guidance.