I66: Occlusion and stenosis of cerebral arteries, not resulting in cerebral infarction

Codes under I66 (Occlusion and stenosis of cerebral arteries, not resulting in cerebral infarction). A ✓ marks a billable (fully specified) code; category codes without a ✓ are not billable on their own.

Code	Description	Billable
I66.0	Occlusion and stenosis of middle cerebral artery	—
I66.01	Occlusion and stenosis of right middle cerebral artery	✓
I66.1	Occlusion and stenosis of anterior cerebral artery	—
I66.02	Occlusion and stenosis of left middle cerebral artery	✓
I66.2	Occlusion and stenosis of posterior cerebral artery	—
I66.03	Occlusion and stenosis of bilateral middle cerebral arteries	✓
I66.3	Occlusion and stenosis of cerebellar arteries	✓
I66.8	Occlusion and stenosis of other cerebral arteries	✓
I66.09	Occlusion and stenosis of unspecified middle cerebral artery	✓
I66.9	Occlusion and stenosis of unspecified cerebral artery	✓
I66.11	Occlusion and stenosis of right anterior cerebral artery	✓
I66.12	Occlusion and stenosis of left anterior cerebral artery	✓
I66.13	Occlusion and stenosis of bilateral anterior cerebral arteries	✓
I66.19	Occlusion and stenosis of unspecified anterior cerebral artery	✓
I66.21	Occlusion and stenosis of right posterior cerebral artery	✓
I66.22	Occlusion and stenosis of left posterior cerebral artery	✓
I66.23	Occlusion and stenosis of bilateral posterior cerebral arteries	✓
I66.29	Occlusion and stenosis of unspecified posterior cerebral artery	✓

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Informational only, not coding or medical advice. Verify against the official ICD-10-CM (FY2026) and your payer's guidelines.

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