Minute changes of cerebral parenchymal non-contrast computed tomography attenuation reflect cerebral volume alterations of blood

2021 ◽  
pp. 197140092199898
Author(s):  
Takamitsu Uchizawa
Keyword(s):  
Computed Tomography ◽  
Cerebral Blood Volume ◽  
Haemoglobin Concentration ◽  
Processing Method ◽  
Regional Cerebral Blood ◽  
Hounsfield Units ◽  
Computed Tomography Images ◽  
Regional Cerebral Blood Volume ◽  
Cerebral Parenchyma ◽  
Attenuation Values

Aims Non-infarcted acute cerebral ischaemic areas appear hypo-attenuated on non-contrast narrow-window computed tomography images. We aimed to determine the mechanism underlying minute computed tomography hypo-attenuation and visualise these attenuation changes on non-contrast computed tomography images. Methods The cerebral parenchyma was defined by pixels with attenuation of 20–50 Hounsfield units. We calculated the mean cerebral parenchymal attenuation in non-contrast computed tomography images. We analysed the correlation of complete blood counts with corresponding mean cerebral parenchymal attenuation values using linear regression analysis. Moreover, we developed an image processing method that involved pixel colorisation based on the noise-reduced attenuation value for minute cerebral parenchymal attenuation visualisation. Results Haemoglobin, haematocrit and red blood cell counts positively correlated with mean cerebral parenchymal attenuation values. The cerebral haematocrit is correlated with the blood haematocrit; therefore, cerebral parenchymal attenuation correlated linearly with cerebral haemoglobin concentration. Haemoglobin contents in a pixel partially determine the X-ray absorption dose and attenuation value. Pixel haemoglobin contents are determined by the cerebral volume of blood in a pixel. Image processed computed tomography images reflected cerebral volume of blood and showed the same alterations with regional cerebral blood volume maps of perfusion computed tomography. Conclusions Cerebral parenchymal attenuation correlated with cerebral haemoglobin concentration and cerebral volume of blood. Infarcted cerebral parenchyma shows about 5 Hounsfield units gray matter attenuation decrease. Attenuation decrease by less than 5 Hounsfield units means decreased cerebral volume of blood, indicating a reversible functional change. One cannot recognise minute hypo-attenuation (<5 Hounsfield units) in routine computed tomography images. However, it can be visualised through an image processing method on non-contrast computed tomography images. It may detect pre-infarction cerebral volume of blood and regional cerebral blood volume alterations.

Lingual dermoid cyst with congenital discharging sinus: a rare entity

2012 ◽  
Vol 127 (2) ◽  
pp. 211-214 ◽  
Author(s):  
Z Sun ◽  
L Sun ◽  
Y Gao ◽  
X Ma
Keyword(s):  
Computed Tomography ◽  
English Language ◽  
Fatty Tissue ◽  
Rare Entity ◽  
Hounsfield Units ◽  
Radiological Features ◽  
Computed Tomography Images ◽  
Attenuation Values ◽  
Congenital Fistula ◽  
Language Literature

AbstractObjective:There have been few reports of lingual dermoid cysts with a congenital discharging fistula. We report such a case, which mimicked lipoma on computed tomography, and we discuss relevant clinical and radiological features.Method:We present a case report and a review of the English language literature concerning lingual dermoid cysts either mimicking lipoma or with a congenital discharging sinus.Results:A 35-year-old man presented with a lingual mass associated with a congenital fistula in the midline of the tongue dorsum, which discharged abnormal secretions. Computed tomography images showed that the lesion was well defined and contained homogeneous fatty tissue giving computed tomography attenuation values of −120 Hounsfield units.Conclusion:Lingual dermoid cysts may develop with a midline discharging fistula, and may exhibit radiological similarity to lipomas on computed tomography.

Effects of subarachnoid hemorrhage on cerebral blood volume, blood flow, and oxygen utilization in humans

1977 ◽  
Vol 46 (4) ◽  
pp. 446-453 ◽  
Author(s):  
Robert L. Grubb ◽  
Marcus E. Raichle ◽  
John O. Eichling ◽  
Mokhtar H. Gado
Keyword(s):  
Blood Flow ◽  
Subarachnoid Hemorrhage ◽  
Blood Volume ◽  
Cerebral Vasospasm ◽  
Cerebral Blood Volume ◽  
Neurological Deficits ◽  
Regional Cerebral Blood ◽  
Oxygen Utilization ◽  
Ruptured Intracranial Aneurysm ◽  
Regional Cerebral Blood Volume

✓ Forty-five studies of regional cerebral blood volume (rCBV), regional cerebral blood flow (rCBF), and regional cerebral oxygen utilization (rCMRO2) were performed in 30 patients undergoing diagnostic cerebral angiography for evaluation of a subarachnoid hemorrhage due to a ruptured intracranial aneurysm. Tracer methods employing radioactive oxygen-15 were used to measure rCBV, rCBF, and rCMRO2. The patient studies were divided into groups based on their neurological status and the presence or absence of cerebral vasospasm. Subarachnoid hemorrhage, with and without vasospasm, produced significant decreases in CBF and CMRO2. In general, patients with more severe neurological deficits, and patients with more severe degrees of vasospasm, had a more marked depression of CBF and CMRO2. The most striking finding was a significant (p < 0.001) increase in CBV (to 58% above normal) in patients with severe neurological deficits associated with severe cerebral vasospasm. This large increase suggests that cerebral vasospasm consists of constriction of the large, radiographically visible extraparenchymal vessels accompanied by a massive dilation of intraparenchymal vessels.

Variations in the measurement of regional cerebral blood volume by cat

1978 ◽  
Vol 2 (2) ◽  
pp. 63-68 ◽  
Author(s):  
Jean-Marie Caillé ◽  
Philippe Constant ◽  
Jean Billerey ◽  
Anne-Marie Renou
Keyword(s):  
Blood Volume ◽  
Cerebral Blood Volume ◽  
Regional Cerebral Blood ◽  
Regional Cerebral Blood Volume

scholarly journals Measurement of Glucose Utilisation with [18F]2-Fluoro-2-Deoxy-D-Glucose: A Comparison of Different Analytical Methods

1987 ◽  
Vol 7 (2) ◽  
pp. 161-172 ◽  
Author(s):  
Adriaan A. Lammertsma ◽  
David J. Brooks ◽  
Richard S. J. Frackowiak ◽  
Ronald P. Beaney ◽  
Sigrid Herold ◽  
...  
Keyword(s):  
Blood Volume ◽  
Rate Constants ◽  
Analytical Methods ◽  
Cerebral Blood Volume ◽  
Normal Subjects ◽  
Inhalation Technique ◽  
Regional Cerebral Blood ◽  
Glucose Utilisation ◽  
Regional Cerebral Blood Volume ◽  
Dynamic Techniques

A number of different analytical methods were applied to dynamic scans obtained with [18F]2-fluoro-2-deoxy-d-glucose and positron emission tomography. In particular, methods applying three, four, standard, or no rate constants were compared in four studies on three normal subjects. In addition, regional cerebral blood flow, oxygen utilisation, and blood volume were measured using the oxygen-15 steady-state inhalation technique. There was a large difference between values of glucose utilisation obtained with the various analytical methods, in particular between methods using three or four rate constants. This difference was not due to contamination of the tracer with [18F]2-fluoro-2-deoxy-d-mannose. For dynamic techniques, the separate measurement of regional cerebral blood volume was essential. Static techniques (single scans with standard or no rate constants) were best related to dynamic techniques utilising four rate constants. From the results, it followed, however, that these static techniques can only be applied clinically if relatively large disturbances of glucose metabolism and no changes in rate constants are anticipated. The lumped constant was assessed from the combined measurement of oxygen and glucose utilisation and was higher than previously reported.

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