Intracranial Hemorrhage (ICH)

Diagnosis Definition

• Intracranial hemorrhage (ICH) can be intracerebral (within the brain) and extracerebral (e.g., subarachnoid, subdural, and epidural)
• The most common cause of ICH between ages 45 and 70 is hypertensive hemorrhage
• Cerebral amyloid angiopathy (CAA) is also an important cause of spontaneous ICH in the elderly
• Tumors with a propensity to bleed include glioblastoma multiforme and vascular metastatic lesions including melanoma, thyroid carcinoma, renal cell carcinoma, and choriocarcinoma
• Other common causes of ICH are coagulopathy, trauma, vascular malformations, vasculitis and hemorrhagic infarction

Imaging Findings

• The MR appearance of ICH is complex and depends primarily on whether the blood is in the deoxyhemoglobin, intracellular methemoglobin, extracellular methemoglobin, or hemosiderin state
• Hypertensive hemorrhage most commonly occurs in the deep gray matter, brainstem and cerebellum, often with intraventricular extension
• Compared with hypertensive ICH, CAA typically spares basal ganglia, uncommonly extends intraventricularly, and is associated with different ages of lobar hemorrhage
• Tumor-associated hemorrhage is heterogeneous in appearance due to mixed signals of hemorrhage, nonhemorrhagic tumor tissue, cystic/necrotic change, and greater degrees of vasogenic edema

KEY IMAGES

Pearls

• MRI gradient echo and susceptibility-weighted imaging is superior to CT in detecting chronic hemorrhages and microbleeds, and better at identifying underlying etiology including structural lesions
• Contrast-enhanced MRI can show rim enhancement of metastatic lesions as well as subacute hematomas

References

1. Heit JJ, Iv M, Wintermark M. Imaging of intracranial hemorrhage. J Stroke 2017; 19(1):11-27
2. William WG Jr. MRI of intracranial hemorrhage. Contemporary Diagnostic Radiology 2016; 39(10):1-6