Hyperdense MCA Sign: NEET PG Radiology
1. The Concept
The Hyperdense MCA Sign is an early, highly specific sign of an acute ischemic stroke caused by an embolus or thrombus occluding the middle cerebral artery (MCA).
2. High-Yield Essentials
- Appearance: A bright, white (hyperdense) segment within the MCA on a non-contrast CT (NCCT) scan. It looks significantly brighter than the contralateral, healthy MCA.
- Specificity: Highly specific (approaching 100%) for an acute MCA clot.
- Sensitivity: Low sensitivity. The sign is absent in many stroke cases, so a negative scan does not rule out a stroke.
3. Differential Diagnosis
| Condition | Key Distinction |
|---|---|
| Calcified Arteries | Seen in elderly patients with atherosclerosis; usually bilateral and continuous along the vessel. |
| Elevated Hematocrit | Can cause generalized vessel hyperdensity; check for bilateral involvement. |
4. Management & Clinical Pearls
- Diagnostic Action: If this sign is present on an initial NCCT, it strongly supports the decision for mechanical thrombectomy in patients who meet the criteria.
- Timing: It is one of the earliest markers of ischemia, often visible within the first 90 minutes of symptom onset.
- Practice Resources: For further study, clinical vignettes, and high-yield question banks, visit mymedschool.org.