Intracranial Hemorrhage Evaluation with MRI
Immediate deaths are seen in 25 of acute traumatic head injuries 3. To differentiate between intracranial atherosclerotic plaque, vasculitis, reversible cerebral vasoconstriction syndrome, arterial dissection, and other causes of intracranial arterial narrowing. A section of the skull is removed for an extended period of time, to allow the injured brain to expand and swell without permanent damage. These features suggest rupture of the aneurysm. During the acute phase, the clot retracts, increasing the hematocrit and surrounding edema, which appears as a hyperintense perilesional rim on T2-weighted MRI.
Dating subdural hematomas and plavix, r niall and selena dating will anderson. CT and MR in infants with pericerebral collections and macrocephaly: The chronic component arrow is hypointense on both T1-weighted and T2-weighted imaging. Use of fat-suppression techniques, such as chemical shift imaging or inversion recovery sequences eg, short-tau inversion recovery [STIR] can help differentiate fat from hemorrhage. To recognize the presence of blood. Cavernous hemangiomas have a typical popcorn-like pattern with a well-delineated complex and reticulated core of mixed signal intensity due to hemorrhage in different phases.
A susceptibility effect is present because the RBC membrane remains intact. Hence, continued hypointensity is observed on T2-weighted images. Over several days to weeks, the energy status of the RBC declines, causing a loss of cellular integrity, and the cells lyse. This event marks the beginning of the late subacute phase. As the loss of RBC integrity removes the paramagnetic aggregation responsible for susceptibility-induced T2 relaxation, T2 shortening disappears.
Methemoglobin freely diffuses in the hematoma cavity in a locally homogeneous magnetic field. This pattern lengthens T2 and, hence, increases the signal intensity on T2-weighted imaging. Extracellular methemoglobin further enhances T1 relaxation, which manifests as high signal intensity on T1-weighted images. The diagnosis of subacute subarachnoid hemorrhage is important because rebleeding may occur with subsequent life-threatening hemorrhage. Over months, the hematoma enters the chronic phase.
As methemoglobin is broken down into small degradation products, its shortening effects are lost. The degree of hyperintensity on T1- and T2-weighted images lessens as the concentration of methemoglobin decreases with protein breakdown.
The center of the hematoma may evolve into a fluid-filled cavity with signal intensity characteristics identical to those of CSF. In addition, the walls of the cavity may collapse, leaving a thin slit. As proteins are degraded, iron atoms that are liberated from the heme molecule are scavenged by macrophages and converted into ferritin, which can be recycled. In most cases, the degree of iron deposition overwhelms the recycling capacity, and the excess is locally concentrated into hemosiderin molecules.
The iron in hemosiderin does not have access to water protons and, therefore, exerts only a susceptibility effect without notable dipole-dipole interactions. These processes lead to marked hypointensity seen at the rim of the hematoma on T2-weighted MRIs. This appearance may persist indefinitely. Evolution of Intraparenchymal Hematoma Open Table in a new window.
Like parenchymal hemorrhage, subdural hematoma SDH has 5 distinct stages of evolution and, therefore, 5 appearances on MRI see the image below. Because the dura is well vascularized and because oxygen tension remains high, progression from one stage to another is slower in the lesion than in the brain. The first 4 stages are the same as those for parenchymal hematoma, with the same T1 and T2 characteristics.
The chronic stage is characterized by continued oxidative denaturation of methemoglobin, which leads to the formation of nonparamagnetic hemochromates. Also, no hemosiderin rim is seen in the surrounding hematoma and no tissue macrophages are present.
EDHs are differentiated from SDH on the basis of their classic biconvexity versus medially concavity and on the basis of the intensity of the fibrous dura matter. See the images below. Immediately after SAH, T1 slightly decreases. This change reflects the increase in the hydration layer due to the elevated protein content of the bloody CSF.
This process subtly increases signal intensity in the CSF on T1-weighted images. Therefore, T1 shortening is seldom seen. In this case, a fluid-fluid level or a subarachnoid or intraventricular thrombus may be present. On T1-weighted images, acute SAH may appear as intermediate or high signal intensity in the subarachnoid space.
Magnetic resonance angiography MRA may be useful in the evaluation of aneurysms and other vascular lesions that cause SAH. Factors that limit the utility of MRI in the diagnosis of acute SAH are its low sensitivity for aneurysms less than 5 mm, its inability to depict small aneurysm contour irregularities, and its difficulty in providing high-quality images in patients who are agitated or confused.
MRI, CTA, and angiography may be adequate for identifying and characterizing lesions to enable early surgery to manage ruptured intracranial aneurysms without a need for intra-arterial digital subtraction angiography in the acute phase of the illness. Primary IVH is rare. It is associated with hypertension, rupture of an aneurysm in the anterior communicating artery, anticoagulation, vascular malformation, moyamoya disease, and intraventricular tumors.
In a retrospective analysis of patients with SAH undergoing diffusion-weighted MR imaging within 72 hours of onset, age-adjusted ADC apparent diffusion coefficient values were globally increased in patients with SAH compared with controls, even in normal-appearing regions, suggesting diffuse vasogenic edema. Cytotoxic edema was also present in patients with SAH and correlated with more severe early injury. Hypertensive hemorrhage is the most common cause of intracranial hemorrhage ICH.
Hypertensive hemorrhage leads to degenerative cerebral microangiopathy characterized by hyalinization of the walls of small arteries and arterioles and, ultimately, fibrinoid necrosis.
Because of hypertension, ICH most commonly involves the lenticulostriate arterial branches of the middle cerebral artery, leading to putaminal or caudate hemorrhage. Large hematomas often dissect into the ventricles, causing intraventricular extension. Infarcted brain tissue has a propensity to bleed, particularly when reperfused in the acute phase.
Hemorrhage due to brain infarction may be recognized because of the associated cytotoxic edema that conforms to an arterial territory. However, this association may be difficult to diagnose when early massive bleeding obscures the underlying infarct.
The risk of venous infarction is higher with bleeding than with arterial infarction. Blood from a ruptured saccular aneurysm enters the subarachnoid space. If it is under great pressure, it occasionally dissects into the brain parenchyma. The locations most commonly involved are the medial frontal lobe adjacent to a ruptured anterior communicating artery or anterior communicating artery or an aneurysm of the anterior cerebral artery and the temporal lobes adjacent to a ruptured aneurysm of the middle cerebral artery.
Vascular malformations, such as arteriovenous malformations AVMs , arteriovenous dural fistulae, and cavernous malformations, can manifest with brain hemorrhage. Both venous angiomas and capillary telangiectasias are generally benign lesions and generally not associated with hemorrhage.
Catheter angiography is often needed to further evaluate AVMs and arteriovenous dural fistula. Areas of increased signal intensity may be due to slow or turbulent flow or thrombosis.
Also seen are areas of hemorrhages in different stages. Cavernous hemangiomas have a typical popcorn-like pattern with a well-delineated complex and reticulated core of mixed signal intensity due to hemorrhage in different phases. Developmental venous anomalies, formerly known as venous angiomas, appear as a stellate tangle of venous tributaries that drain into a large, sharply delineated vein, which often shows high-velocity signal loss.
Contusions frequently occur in the basal anterior frontal and temporal lobes where the brain is adjacent to the bony floor of the anterior and middle cranial fossae. They may be seen in the cortex ipsilateral or contralateral to the side of injury. Contusions can be multiple, and they may be associated with other evidence of trauma, such as skull fracture, subdural hematoma SDH , epidural hematoma EDH , or subgaleal hematoma.
Brain tumors may be associated with significant neovascularity, breakdown of the blood-brain barrier, and an increased risk for hemorrhage. High-grade tumors such as glioblastoma multiforme, and certain metastases eg, melanoma, renal cell carcinoma, thyroid carcinoma, choriocarcinoma are more likely to bleed than others.
Metastases from lung cancer can also bleed. MRI appearances are often atypical and complex because blood of differing ages may be present and admixed with abnormal neoplastic tissue. The evolution of changes in MRI signal intensity is often delayed. Vasogenic edema is greater with brain tumors than with primary ICH, and it persists even into the chronic phase of hematoma. Administration of gadolinium-based contrast medium may reveal tumor enhancement.
CAA often causes hemorrhage in the cortex or in the subcortical white matter of the cerebrum or, in rare instances, the cerebellum. Dissection into the subarachnoid space is common, whereas ventricular extension is uncommon. Other causes of ICH are vasculitis, moyamoya disease , anticoagulation therapy, and coagulopathies. MRA is potentially useful for identifying secondary causes of hemorrhage, such as saccular aneurysm or vascular malformation, which may require urgent intervention.
CTA is also quite useful. Direct signs of dural sinus thrombosis on magnetic resonance venography MRV include absence of the typical high-flow signal intensity from a sinus that does not appear aplastic or hypoplastic on single sections from MRA and the frayed appearance of the flow signal from a sinus after recanalization.
Indirect signs of dural sinus thrombosis include evidence of the formation of collaterals, unusually prominent flow signal from the deep medullary veins, cerebral hemorrhage, visualization of emissary veins, and signs of increased intracranial pressure.
On MRI, hemorrhage is occasionally confused with other pathologies or conditions that cause hyperintensity on T1-weighted images. Examples are lesions containing fat, protein, calcification, and melanin. On T1-weighted images, melanotic metastases have hyperintensity similar to that of intracellular and extracellular methemoglobin.
However, metastases from melanoma less commonly display susceptibility on gradient recalled-echo images, and they typically show some contrast enhancement. Lesions containing fat, such as lipomas or dermoids , are also hyperintense on T1-weighted images.
Fat appears hypointense on conventional spin-echo T2-weighted images and hyperintense on turbo fast spin-echo T2-weighted images. Use of fat-suppression techniques, such as chemical shift imaging or inversion recovery sequences eg, short-tau inversion recovery [STIR] can help differentiate fat from hemorrhage.
The presence of a chemical shift artifact may also indicate a fatty lesion. Hemorrhagic metastases usually show intense contrast enhancement, which is not seen in bland hematomas.
Calcification may mimic hemorrhage, as both result in profound hypointensity on gradient-echo images. However, differences in the morphology and location of the abnormal signal intensity and in the clinical presentation suffice to distinguish the two. CT may also help differentiate these entities. As hemorrhage evolves, it passes through 5 well-defined and easily identified stages, as seen on MRI. Knowledge of these stages may be useful for dating a single hemorrhagic event or for ascertaining if multiple hemorrhagic events occurred at different times.
MRI is also more specific than CT in determining the age of a hemorrhage. Magnetic Resonance Imaging of the Brain and Spine. Hemorrhage and brain iron. MR pattern of hyperacute cerebral hemorrhage. J Magn Reson Imaging. Lanzman B, Heit JJ. Top Magn Reson Imaging.
Imaging of brain metastases. Magnetic resonance imaging versus computed tomography for identification and quantification of intraventricular hemorrhage. J Stroke Cerebrovasc Dis. Conventional and high-resolution vessel wall MRI of intracranial aneurysms: MR appearance of hemorrhage in the brain. MR characteristics of subdural hematomas and hygromas at 1. MRI features of intracerebral hemorrhage within 2 hours from symptom onset.
Rapid MRI evaluation of acute intracranial hemorrhage in pediatric head trauma. Detection of hyperacute primary intraparenchymal hemorrhage by magnetic resonance imaging. Satoh S, Kadoya S. Magnetic resonance imaging of subarachnoid hemorrhage. Neuroimaging Clin N Am. Diffusion-weighted signal patterns of intracranial haemorrhage. Double inversion recovery MR sequence for the detection of subacute subarachnoid hemorrhage.
Retrospective review of previous minor leak before major subarachnoid hemorrhage diagnosed by MRI as a predictor of occurrence of symptomatic delayed cerebral ischemia. Guidelines for the Management of Spontaneous Intracerebral Hemorrhage: Wu Q, Li MH. Sign Up It's Free! If you log out, you will be required to enter your username and password the next time you visit.
Share Email Print Feedback Close. Practice Essentials The appearance and evaluation of intracranial hemorrhage on MRI see the images below primarily depend on the age of the hematoma and on the imaging sequence or parameters eg, T1 weighting, T2 weighting. Axial T1-weighted image T1W shows isointense to hypointense lesion in the right temporoparietal region that is hyperintense on T2-weighted T2W imaging and with susceptibility appearing as low signal intensity due to blood on gradient-echo GRE images.
Of course, trauma can be a cause for ICVT and subdural hemorrhage alike. Finally, there has been recent controversy raised over whether hypoxic ischemic encephalopathy HIE is a potent cause of SDH which may mimic the features of abusive head trauma.
Of course, childbirth related subdural hemorrhage may occur in conjunction with HIE without a causal relationship. Finally In addition to the key observations that the radiologist must make in the setting of suspected abusive head trauma, there must be an awareness that some disorders may either as a result of mechanical distortion or neurodegeneration predispose to the development of non-traumatic SDH Table 3.
It is worth remembering that physical abuse is more common among children with chronic illness. The radiologist shoulders an important responsibility when it comes to reporting imaging findings suggesting abusive head trauma. The law is clear in this regard. For the radiologist, there is a legal responsibility to report findings suspicious for AHT. These guidelines are outlined by the American College of Radiology, and can be reviewed at http: Documentation of the individual contacted, the method of communication, the date and time are minimal requirements.
As a mandatory reporter, the radiologist is protected from civil and criminal prosecution by Shield Laws that exist within the United States. Subdural Hemorrhage in Abusive Head Trauma: Imaging Challenges and Controversies. J Am Osteopath Coll Radiol. Background of abusive head trauma In the neonate, infant, or young child who has suffered from non-accidental injury, abusive head trauma AHT is acknowledged as the most common cause of fatality and long term morbidity with approximately 1, fatalities and 18, seriously disabled infants and children annually in the USA.
Imaging goals in the evaluation of abusive head trauma The goals for the medical imaging physician who is responsible for interpreting brain CT and MRI examinations for the pediatric patient with suspected abusive head trauma are clearly defined.
Birth related subdural hemorrhage Birth related SDH can lead to confusion and controversy particularly when SDH is detected in a young infant. Subdural hemorrhage and intracranial venous thrombosis In the differential diagnostic consideration of non-traumatic causes of SDH, some authors opine and testify to the fact that intracranial venous thrombosis ICVT may lead to the development of SDH that mimics the SDH of abusive head trauma.
Hypoxic ischemic encephalopathy and subdural hemorrhage Finally, there has been recent controversy raised over whether hypoxic ischemic encephalopathy HIE is a potent cause of SDH which may mimic the features of abusive head trauma. Neuroimaging of abusive head trauma. Medina LS, et al. Imaging of nonaccidental head injury. Evidence-Based Imaging in Pediatrics ; Neuroimaging of nonaccidental head trauma; pitfalls and controversies. Pediatric Radiol ; Barnes P, Krasnokutsky M.
Top Magn Reson Imaging ; Wang CT, Holton J. Total estimated cost of child abuse neglect in the United States. Prevent Child Abuse America Web site. Subdural hematoma and non-accidental head injury in children.
Assessment of the nature and age of subdural collections in nonaccidental head injury with CT and MRI. Pediatric Radiol, ; Eur Radiol, ; MR characteristics of subdural hematomas and hygromas at 1.
The computed tomographic attenuation and the age of subdural hematomas. J Korean Med Sci ; Imaging of head injuries in infants: J Neurosurg Pediatrics 1 ; CT mimic of recurrent episodes of bleeding in the setting of child abuse. Magnetic resonance in imaging of chronic subdural hematoma. Neurosurg Clin N Am. Comparison of accidental and nonaccidental traumatic head injury in children on noncontrast computed tomography.
Comparison of intracranial computed tomographic findings in pediatric abusive and accidental head trauma. Pediatr Rad ; Munro D, Merritt H. Surgical pathology of subdural hematoma. Based on a study of cases. The aetiology of subdural hematoma: J Nerv Ment Dis. Intacranial hemorrhage and rebleeding in suspected victims of abusive head trauma: Child Maltreat ; 7: Intracranial hemorrhage in term with newborns: Pediatr Neurol ; Prevalence and evolution of intracranial hemorrhage in asymptomatic term infants.
Sonographic findings in infants with macrocrania. CT and MR in infants with pericerebral collections and macrocephaly: Benign enlargement of the subarachnoid spaces versus subdural collections. Subdural hygroma versus atrophy on MR brain scans: Subdural hematoma in infants: Data from a prospective series and critical view of the literature.
Subdural hematomas in infants with benign enlargement of the subarachnoid spaces are not pathognomonic for child abuse. Ravid S, Maytal J. Influence of the benign enlargement of the subarachnoid space on the bridging veins strain during a shaking event: Int J Legal Med. Spektor Amodio, Pramanik B et al. Spontaneous development of bilateral subdural hematomas in an infant with benign infantile hydrocephalus: Pediatr Radiol ;
Imsges: dating subdural hematoma mri
To localize and differentiate hemorrhages extra-axial versus intra-axial:
Late subacute hemorrhage see the following image MR images show late subacute hemorrhage in both thalamic regions in a patient with known cerebral malaria. This dipole-dipole interaction shortens both T1 and T2 relaxation times, with a greater effect on T1 than on T2.
Using MR as a means of dating subdural hemorrhage is even more complex than CT dating for reasons mentioned above. Histologic dating of subdural hematomas is imprecise, and caution must be. Elderly people are at higher risk for chronic subdural hematoma because brain shrinkage causes these tiny veins to be more stretched and more vulnerable to tearing. SDH of accidental cause was more homogeneous, unilateral and coup to the site of impact Fig dating subdural hematoma mri. A susceptibility effect is present when iron atoms are compartmentalized in the RBC membrane. Practice Essentials The appearance and evaluation of intracranial hemorrhage on MRI see the dating subdural hematoma mri below primarily depend on the age of the hematoma and on the imaging sequence or parameters eg, T1 weighting, T2 weighting. A relatively minor head injury can cause subdural hematoma in people with a bleeding tendency.
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