Hyperattenuating (“Dense”) Artery

Sheri L. Harder, MD

DIFFERENTIAL DIAGNOSIS

Common

Less Common

Rare but Important

ESSENTIAL INFORMATION

Key Differential Diagnosis Issues

Presence, localization of focal neurologic findings important
High hematocrit/hemoconcentration can mimic “dense MCA sign”!
- Compare to other intracranial vessels!
Diffuse low density brain (anoxia, etc.) makes ALL vessels appear hyperdense, mimics thrombus or SAH!

Helpful Clues for Common Diagnoses

Physiologic Hyperdensity
- Circulating blood in arteries normally slightly hyperdense to brain
  - Especially prominent in newborns with unmyelinated, hypodense brain
  - Diffuse cerebral edema makes vessels appear hyperdense (“false dense MCA sign”)
Cerebral Ischemia-Infarction, Acute
- Acute thrombus in affected vessel (e.g., true “dense MCA sign”)

Helpful Clues for Less Common Diagnoses

Atherosclerosis, Intracranial
- ASVD with microcalcifications can mimic “dense” MCA
Polycythemia
- Can be physiologic (elevated hematocrit in newborns, high altitude, etc.)
- Numerous pathologic causes
Fusiform Aneurysm (ASVD, Non-ASVD)
- Vertebrobasilar > carotid circulation
- Thickened walls may appear hyperdense
- Non-ASVD: Younger; inherited vasculopathy, immune disorder
Dissection
- Most posterior circulation
- Trauma most common etiology
Pseudoaneurysm
- Trauma most common etiology

Helpful Clues for Rare Diagnoses

Devices and Complications
- Coils, balloons, stents, methacrylate, etc.
- Embolized foreign bodies, calcified atheromata can cause hyperattenuating vessel sign