A 68-year-old man with hypertension presents with sudden onset hemiparesis and headache. CT head shows a hyperdense lesion in the basal ganglia with surrounding hypodensity. Which imaging feature best distinguishes hypertensive intracerebral hemorrhage from amyloid angiopathy-related hemorrhage?

Explanation

## Distinguishing Hypertensive ICH from Amyloid Angiopathy ICH ### Location: The Primary Discriminator **Key Point:** The anatomical location of the hemorrhage is the most reliable imaging discriminator between hypertensive intracerebral hemorrhage (ICH) and cerebral amyloid angiopathy (CAA). | Feature | Hypertensive ICH | Amyloid Angiopathy ICH | |---------|------------------|------------------------| | **Typical location** | Deep structures: basal ganglia, thalamus, pons, cerebellum | Lobar (cortical) and subcortical | | **Vessel affected** | Lipohyalinotic small penetrating arteries | Amyloid-laden cortical vessels | | **Number of bleeds** | Usually solitary, large | Often multiple (microhemorrhages) | | **SWI/GRE findings** | Single large bleed | Multiple microhemorrhages ("blooming" on GRE) | | **Recurrence risk** | Lower if BP controlled | Higher; lobar location predicts recurrence | | **Age of onset** | Any age with HTN; typically 40–70 years | Elderly (>70 years); often normotensive | ### Pathophysiology Underlying Location **High-Yield:** Hypertensive ICH occurs because chronic hypertension causes **lipohyalinosis** of small penetrating arteries (Charcot-Bouchard aneurysms) that supply the deep gray matter and brainstem. These vessels rupture, causing large, solitary hemorrhages. Amyloid angiopathy causes hemorrhage in **cortical and subcortical vessels** because amyloid-β deposits in the media of small cortical arteries, weakening them. This predisposes to multiple microhemorrhages and recurrent lobar bleeds. ### Imaging Pearls **Clinical Pearl:** Susceptibility-weighted imaging (SWI) or gradient-recalled echo (GRE) sequences are exquisitely sensitive for detecting microhemorrhages. Multiple microhemorrhages (especially in a lobar distribution) are a hallmark of CAA and predict future hemorrhagic events. **Warning:** Do not confuse the presence of mass effect or acute presentation — both can occur in either condition. Mass effect depends on bleed size, not etiology. Acute presentation is universal in both. ### Mnemonic **Mnemonic:** **DEEP** = **D**eep structures = hypertensive; **LOBAR** = amyloid (Lobar = Amyloid). [cite:Harrison 21e Ch 445; Robbins 10e Ch 28]