Variation with Time of the Attenuation Values of Intracranial Hematomas

Bergström, Mats; Ericson, K.; Levander, Bo; Svendsen, P.; Larsson, Stig

doi:10.1097/00004728-197701000-00008

Cited by 87 publications

(16 citation statements)

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“…1a) [9,10]. This is due to the formation of a complex, inhomogeneous mass that contains red blood cells (RBCs), white blood cells (WBCs), and small platelet clumps interspersed with protein-rich serum.…”

Section: Computed Tomographymentioning

confidence: 99%

Intracranial hemorrhage: principles of CT and MRI interpretation

et al. 2001

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Accurate diagnosis of intracranial hemorrhage represents a frequent challenge for the practicing radiologist. The purpose of this article is to provide the reader with a synoptic overview of the imaging characteristics of intracranial hemorrhage, using text, tables, and figures to illustrate time-dependent changes. We examine the underlying physical, biological, and biochemical factors of evolving hematoma and correlate them with the aspect on cross-sectional imaging techniques. On CT scanning, the appearance of intracranial blood is determined by density changes which occur over time, reflecting clot formation, clot retraction, clot lysis and, eventually, tissue loss. However, MRI has become the technique of choice for assessing the age of an intracranial hemorrhage. On MRI the signal intensity of intracranial hemorrhage is much more complex and is influenced by multiple variables including: (a) age, location, and size of the lesion; (b) technical factors (e.g., sequence type and parameters, field strength); and (c) biological factors (e.g., pO2, arterial vs. venous origin, tissue pH, protein concentration, presence of a blood-brain barrier, condition of the patient). We discuss the intrinsic magnetic properties of sequential hemoglobin degradation products. The differences in evolution between extra- and intracerebral hemorrhages are addressed and illustrated.

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Section: Computed Tomographymentioning

confidence: 99%

Intracranial hemorrhage: principles of CT and MRI interpretation

et al. 2001

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“…Similarly, we did not perform CT in patients with focal signs due to conditions which could be diagnosed on clinical grounds alone, such as Bell's palsy. There were, however, 16 patients in this group who had symptoms and signs suggestive of a non-stroke intracranial lesion, which was confirmed by CT in 11. Possibly the remaining five, who did not have Cl scans, in fact had strokes (though this seemed highly uinlikely f1rom the clinical historv).…”

Section: Discussionmentioning

confidence: 67%

“…After review of the histories the clinical features in all 11 cases were still not considered in any way suggestive of clinically definite stroke. Five of the 16 patients with suspected non-stroke lesions did not have CT. All five had histologically proved disseminated malignancy from primary tumours outside the central nervous system and developed slowly progressive focal neurological symptoms and signs suggestive of cerebral metastases. Although none of these five had a CT scan or were seen by a study neurologist, and for 233 (72o0 ) a witness account was obtained.…”

Section: Patients Diagnosed As "Clinically Not Stroke'mentioning

confidence: 98%

Value of computed tomography in patients with stroke: Oxfordshire Community Stroke Project.

Sandercock¹,

Molyneux²,

Warlow³

1985

BMJ

141

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The usefulness of computed tomography (CT) was assessed in 325 consecutive patients with a "clinically definite first stroke" from a community stroke register. CT detected five "non-stroke" lesions (two cerebral gliomas, one cerebral metastasis, and two subdural haematomas), a frequency of 15%. Five patients were identified with cerebellar haemorrhage, but only one survived long enough to have a CT scan. CT was useful in excluding intracranial haemorrhage as the cause of the stroke in four patients receiving anticoagulants and seven receiving antiplatelet treatment; it showed intracranial haemorrhage in one patient taking aspirin. Forty six patients were in atrial fibrillation at the time of their stroke; four had intracranial haemorrhages and three had haemorrhagic cerebral infarcts. Nineteen patients with presumed ischaemic minor stroke were considered suitable for carotid endarterectomy; CT showed small haemorrhages in two.The CT scan provides very useful information in a minority (up to 28%) of patients with first stroke, who can be selected on quite simple criteria: (a) doubt (usually because of an inadequate history) whether the patient has stroke or a treatable intracranial lesion; (b) the possibility of cerebellar haemorrhage or infarction; (c) the exclusion of intracranial haemorrhage in patients who either are already taking or likely to need antihaemostatic drugs or are being considered for carotid endarterectomy; (d) if the patient deteriorates in a fashion atypical of stroke.

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“…In vitro, fibrinolysis of a solid clot decreases attenuation by 15-20 HU, blurring the margin between solid and liquid blood. 13 In CSF where HU counts changed relatively little during the period of observation, red blood cells likely fall away from the solid clot and are removed by the steady flow of CSF, which keeps attenuation values low and maintains a clear interface between clot and CSF. The greater decrease in HU counts in patients treated with rtPA compared with controls in Fig 3 likely reflects a combination of increased lytic activity and perhaps improved CSF flow, especially at t2 when most patients treated with rtPA had opened the lower ventricular system.…”

Section: Discussionmentioning

confidence: 98%