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ICD-10-CM 2027

ICD-10 code for circle of Willis aneurysm

I67.1

Cerebral aneurysm, nonruptured

✓ Billable / specific

From the official ICD-10-CM alphabetic index entry “Aneurysm (anastomotic) (artery) (cirsoid) (diffuse) (false) (fusiform) (multiple) (saccular) › circle of Willis”. Page updated September 29, 2026.

About coding circle of Willis aneurysm

The ICD-10-CM code for circle of Willis aneurysm is I67.1 (Cerebral aneurysm, nonruptured). The official index lists 3 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on I67.1.

Within I67 (other cerebrovascular diseases), I67.1 is specifically for cerebral aneurysm, nonruptured. Related codes cover dissection of cerebral arteries, nonruptured (I67.0), cerebral atherosclerosis (I67.2), progressive vascular leukoencephalopathy (I67.3), hypertensive encephalopathy (I67.4), Moyamoya disease (I67.5), nonpyogenic thrombosis of intracranial venous system (I67.6), cerebral arteritis, not elsewhere classified (I67.7), other specified cerebrovascular diseases (I67.8) and 1 more.

Don't report I67.1 together with the conditions in its Excludes1 note: congenital cerebral aneurysm, nonruptured (Q28.-) and ruptured cerebral aneurysm (I60.7).

It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.

More specific circle of Willis aneurysm codes (official index)

  • congenital Q28.3 — Other malformations of cerebral vessels
  • ruptured I60.6 — Nontraumatic subarachnoid hemorrhage from other intracranial arteries
  • ruptured I60.6 — Nontraumatic subarachnoid hemorrhage from other intracranial arteries

Don't confuse with (Excludes1 for I67.1)

  • congenital cerebral aneurysm, nonruptured (Q28.-)
  • ruptured cerebral aneurysm (I60.7)

Common questions about circle of Willis aneurysm ICD-10 codes

What is the ICD-10 code for circle of Willis aneurysm?

I67.1 — Cerebral aneurysm, nonruptured. More specific codes apply when the documentation supports them: Q28.3, I60.6, I60.6.

What is the ICD-10 code for congenital circle of willis aneurysm?

Q28.3 — Other malformations of cerebral vessels.

What is the ICD-10 code for ruptured circle of willis aneurysm?

I60.6 — Nontraumatic subarachnoid hemorrhage from other intracranial arteries.

Is I67.1 billable?

Yes. I67.1 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can I67.1 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict I67.1 as a principal diagnosis.

Is I67.1 a CC or MCC?

No. I67.1 is neither a CC nor an MCC under MS-DRG v44.0.