Imaging of the intracranial heamorrhage

IMAGING OF INTRACRANIAL HAEMORRHAGES

Abdullah Albakri

Objectives

• Normal anatomy• Physical principles• Intraparenchymal haemorrhage (IPH)• Subarachnoid haemorrhage (SAH)• Subdural haematoma (SDH)• Epidural haematoma (EDH)• New imaging applications

Introduction

• IC haemorrhages constitute a heterogeneous group of disorders

• Occur spontaneously or a result of direct trauma to cranium

• Management is closely related diagnostic modalities

Classification

Intraparenchymal haemorrhage

• The most common risk factors

• Hypertension• Has predictable localisation, supplied

by perforators; putamen > subcortical WM, cerebellum > thalamus > pons

• Deep brain

• Cerebral amyloid angiopathy • Elderly • Lobal in nature (posterior)

• Tumors

Imaging modalities (CT)

• NCCT Still the gold standard in many enters

• Degree of x-ray attenuation is determined by• Hematocrit• Blood clot retraction • Hb content

• Heamorrhge avearaging 60 HU to 100 HU

• 3 phases• Acute• Subacute • Chronic

55 Y old man with BP 220/110 mmHg on admission

Acute haemorrhage• Hyperdense

Subacute haemorrhage• Small• Centripetally

Cerebral amyloid angiopathy

Posterior hemisphere acute hemorrhage, such as those observed in patients with amyloid angiopathy. A, The CT shows a small hemorrhage outside of the perforator territories. B, The hemorrhage is hardly visible in T1-weighted imaging, as would be expected in the acute phase. C, Gradient-refocused echo imaging clearly displays the hemorrhage.

Imaging modalities (CT with contrast)

• The routine utilisation of IV contrast is unwarranted(CONTINUUM: Lifelong Learning in Neurology. Neuroimaging. 14(4, Neuroimaging):37-56, August 2008)

• In general, contrast studies are indicated in patients without a clear underlying aetiology or in patients with haemorrhages in unusual locations(Guidelines for the Management of Spontaneous Intracerebral Hemorrhage in Adults: 2007 Update: A Guideline From the American Heart Association/American Stroke Association Stroke Council, High Blood Pressure Research Council, and the Quality of Care and Outcomes in Research Interdisciplinary Working Group: The American Academy of Neurology affirms the value of this guideline as an educational tool for neurologists)

• To detect hematoma expansion “hot spot”• Tumor

History of hypertension with abrupt left hemiparesis

this patient with oat cell carcinoma of the lung prescnted with new onset seizure.

Imaging modalities (MRI)

• Conventional T1WI/T2WI are not sensitive to blood in hyper acute stage

• GRE MRI sequences are as accurate as CT for detection of IPH(Kidwell CS, Chalela JA, Saver JL, et al. Comparison of MRI and CT for detection of acute intracerebral hemorrhage. JAMA 2004;292: 1823–30.)

• Better than CT in detecting underlying structural abnormalities

• The MR signals are determined by• Paramagnetic effects• Pulse sequence • Hb content

• 5 phases• Hyperacute • Acute • Early subacute • Late subacute • Chronic

Oxy Hb —-> Deoxy Hb —-> Met Hb, hemosideren

Oxy Hb De Hb Met Hb Hemosidderen

DiamagneticHigh H2O

Paramagnetic

Paramagnetic

Paramagnetic

T1 Isointense Isointense Hyperintense Isointense

T2 Hyperintense

Hypointense

IC: Hypointens

eEC:

Hyperintense

Hypointense

Case courtesy of Dr Frank Gaillard, radiopaedia.org

Hyperacute hematoma: In this image , it can be observed on sagittal T1-weighted MR a isointense hematoma and axial T2-weighted MR the hematoma is hyperintense. It is located in the right cerebellar hemisphere.

HyperacuteBlood extravasate Intact RBCsIC oxy HbDimagneticHigh water content

Acute Hematoma: Sagittal T1-weighted MR shows a isointense hematoma (arrows) surrounded by a hyperintense halo. Axial T2-weighted MR shows a hypointensity. It corresponds to an acute hematoma (8 hours of evolution). There is also another hematoma of different time of evolution.

Acute

Intact hypoxic RBCsDeoxy HbParamagnetic

Early subacute Hematoma: The hematoma is hyperintense on T1-weighted MRI and hypointense on T2-weighted MRI, due to methemoglobin inside intact red blood cells.

Early subacute

Clot retractionMet HbParamagnetic

Late Subacute intracerebral Hematoma: 67 year-old-male. On sagittal T1- weighted and axial T2-weighted MRI a hyperintense intracerebral hematoma is seen, located in the right cerebral hemisphere. Hyperintensity is due to extracellular methemoglobin. (25 days of evolution).

Late subacute

Cell lysisMet HbParamagnetic

Chronic hematoma: Sagittal T1-weighted MRI and axial T2-weighted MRI in the same patient, show a hypointense hematoma in chronic phase (5 months of evolution). There is, also dilatation of the right lateral ventricle due to adjacent parenchymal atrophy

Chronic

MacrophagesHemosiderinSuperpaeamagnetic

Practical approach• Hyperintensity in T1WI automatically classifies

hematoma as subacute• If so, hyper intensity in T2WI places the

hematoma in late subacute• If the hematoma is isointense on T1WI, the nest

step is to identify the presence of conspicuous hypointense rim on T2WI to classify is as chronic

• If hypointense rim is absent and the hematoma is hyperintense, the lesion is clearly hyperacute

• CONTINUUM: Lifelong Learning in Neurology. Neuroimaging. 14(4, Neuroimaging):37-56, August 2008

Subarachnoid hemorrhage

• The subarachnoid space filled with RBCs suspended within CSF

• Could be traumatic or non-traumatic

• Symptoms develop either to bleeding of mass effect

Imaging modalities

• CT• CT is over 90% sensitive with hyper sense blood seen in

SAS and BCs• Difficult to detect if

• Hematocrit is low• Small haemorrhage • Delayed scanning

• ?

• MRI• Difficult to detect by conventional T1WI/T2WI• FLAIR

• CTA• To detect site of vascular malformation

21-YEAR-OLD MAN COLLAPSED IMMEDIATELY AFTER A LINE OF COCAINE

NCCT SHOWS BLOOD IN THE INTERRHEMISPHCRIC FISSURE AND IN THE DEPENDENT PORTIONS OF THE

LATERAL VENTRICLES.

Lateral view from a digitalsubtractionangiogramdemonstratesalargeanteriorcommunic

atingarte.ryaneurysm(arrow).Ovuhalfofdrugabusers with intracra.ni.al hemorrhage will be found to have an underlying

aneurysm or arteriovenous malformation

Subarachnoid hemorrhage, unenhanced CT scans. Subarachnoid hemorrhage is frequently the result of a ruptured aneurysm. Blood may be most easily visualized within the basal cisterns (solid white arrows in A), in the fissures (dotted white arrows in B), and interdigitated in the subarachnoid spaces of the sulci (dashed white arrow in C). The region of the falx may become hyperdense, widened, and irregularly marginated (solid black arrow in C).

SUBARACHNOID HEMORRHAGE

FLAIR IMAGE

Epidural Hematoma

• Results from trauma, associated with skull fracture (95%)

• Arterial in origin, MMA• Temporal or temporoparietal• The underlying brain may be spared• Almost always acute

EPIDURAL HEMATOMAS

• High density, extra axial Lenticular appearance

• Not cross sutures

Subdural hematoma• Occur in subdural space • Caused by traumatic tearing of bridging

veins (deceleration) • 3 stages• Associated with significant brain injury

due to mass effect• No consistence relationship to skull

fracture

Acute

Subacute

Chronic

SUBDURAL HEMATOMAS

• High attenuation semilunar appearance• Can cross sutures

Acute on chronic

Subdural hematomasSUBDURAL HEMATOMAS

Epidural H. Subdural H.• Convex inner margin• Can cross midline• Almost always acute (post traumatic)

• Concave inner margin• Can not cross midline• Almost always acute

Intraventricular Hemorrhage

• Commonly seen in patients with head injury

• Occur by several mechanisms• Risk of obstructive hydrocephalus • On CT, hyperdense material, layering

dependently

Direct extension Retrograde flow

New imaging applications

Conclusion

References • William E, B., Clyde H. (2012). Fundamentals of Diagnostic

Radiology. LWW

• IMAGING OF INTRACRANIAL HEMORRHAGE. Gomez, Camilo R. CONTINUUM: Lifelong Learning in Neurology. 14(4, Neuroimaging):37-56, August 2008

• Imaging of intracranial haemorrhage. Kidwell, Chelsea S et al.. The Lancet Neurology , Volume 7 , Issue 3 , 256 - 267

• Guidelines for the Management of Spontaneous Intracerebral Hemorrhage in Adults: 2007 Update: A Guideline From the American Heart Association/American Stroke Association Stroke Council, High Blood Pressure Research Council, and the Quality of Care and Outcomes in Research Interdisciplinary Working Group: The American Academy of Neurology affirms the value of this guideline as an educational tool for neurologists