| Objective:1. To map quantitative characteristics of spectral CT imaging of normal adult human brain, expect to provide basic reference for the study of early cerebral ischemia.2. To investigate quantitative characteristics of spectral CT imaging characteristics of cerebral infarction in different periods.3. To explore the value of spectral CT imaging in diagnosis of early cerebral ischemia.Methods:1.20 cases underwent CT spectral imaging with the negative results were grouped according to the gender and age bracket from 30-45 and 45-60. The CT values, blood (iodine), iodine (water) and water (iodine) of different regions in the brain were measured symmetrically. Statistic analysis was performed.2.36 cases with cerebral infarction of different onset time (1 day,3 day,7 day andl5 day) underwent plain CT with CT spectral imaging mode.The CT value of monochromatic images,blood (iodine), iodine (water) and water (iodine) of infarction, encephalomalacia and its contralateral regions were measured in optimal monochromatic energy images and the slope of the spectral HU curve were calculated, statistic analysis was performed, matching spectral HU curve, basic material box plot of blood(iodine) and water(iodine) to compare.3.27 cases undergone one-stop brain CT (plane scan with CT spectral imaging mode, CTP, CTA) to screen for cerebral apoplexy.9 cases presented with low density on plane scan, cerebral infarction surrounded by ischemic penumbra on CTP; 18 cases presented with negative results on plain scan and low perfusion changes of pre-infarction on CTP, relevant vessels stenosis were found on CTA. Monochromatic energy CT values, blood(iodine),iodine(water) and water(iodine) concentration in spectral monochromatic image areas corresponding to ischemic penumbra, low perfusion on CTP(defined as early cerebral ischemia areas) and contralateral regions were measured and the slope of the spectral HU curve was calculated, statistical analysis were performed. Matching spectral HU curve, basic material box plot of blood(iodine) and water(iodine) of affected and healthy sides to compare.Results:1. The mean CT values of white matter in normal human brain on optimal 70keV monochromatic images were 27.21±1.95HU, (iodine) water:1.5±0.72 (100ug/ cm3),iodine (blood):-0.15±0.07 (mg/cm3),blood (iodine):1036.5±0.93 (mg/ cm3),water (iodine):1023.16±0.9 (mg/cm3). The mean CT values of gray matter in normal human brain on optimal 70keV monochromatic images were 5.82± 2.26HU;(iodine) water:4.41±1.59 (100ug/cm3),iodine (blood):0.1±0.14 (mg/ cm3),blood (iodine):1037.78±2.89 (mg/cm3),water (iodine):1024.36±2.83 (mg/ cm3). All the parameters had no statisticant difference in different age and gender groups (P> 0.05).2. With the onset of cerebral infarction 1 day,3 days,7 days, the CT values decreased,blood (iodine),water (iodine) values decreased slightly; the CT value, blood (iodine),water (iodine) values of lesion were slightly higher in 15 days compared with 1 to 7 days; the CT value,blood (iodine),water (iodine) values of encephalomalacia all decreased sharply compared with 1-15 days.3. The CT values, blood (iodine) and water (iodine) in early cerebral ischemia areas were lower than that in contralateral areas (each P<0.05).Conclusion:1. The CT values of monochromatic images and basic material concentrations of spectral CT imaging in normal adult brain varied in a certain range, that can provide the basic reference for spectral CT imaging study of early cerebral ischemia.2. There were some characteristics of changes in spectral HU curve on monochromatic energy and basic material at different periods of cerebral infarction, that can provide a reference for the energy spectrum CT diagnosis of early cerebral ischemia.3. The analysis of CT values of optimal monochromatic images and the basic material can contribute to the suggestive diagnosis of early cerebral ischemia. |
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