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Objective To explore the value of single source dual energy CT for quantitative measurement of liver fat fraction in the rabbit model of nonalcoholic fatty liver disease(NAFLD).Methods Thirty male New Zealand rabbits were randomly divided into five groups.Six rabbits were fed with standard chow as a control group for 3 weeks.TwentyGfour rabbits were divided into four groups and fed with highGfat, highGcholesterol diet to reach different stage of NAFLD model for 1 ,3 ,4 and 8 weeks respectively before dualGenergy CT scanning.1 40 keV polychromatic CT values (QC),70 keV monochromatic CT values (Mono 70 keV),slope,effective atomic number (EffectiveGZ)and fat concentration based on dualGenergy CT fat decomposition (Fat/Water)were measured.Liver samples were obtained to measure the fat fraction and staged according to Burnt staging system.Correlations between different CT indexes and fat fraction were analyzed.ROC was used to evaluate the diagnosis efficacy of different parameters.Results Correlation between fat concentration based on dualGenergy CT fat decomposition and fat fraction (r＝0.936)was better than that between 140 keV polychromatic CT values (r＝－0.838)and 70 keV monochromatic CT values (r＝－0.906),as well as effective atomic number (r＝－0.858)and slope (r＝0.863).In terms of diagnostic performance of material decomposition fat imaging,the values of area under the curve were 0.944 (stage 0 vs.stage 1 or more severe),0.995 (stage 1 or less severe vs.stage 2 or more severe)and 1 (stage 2 or less severe vs.stage 3)with optimal cutoff values of 59.310,99.5 17 and 22 3.02 3 mg/cm3 ,respectively.Conclusion The dualGenergy CT can quantitatively measure liver fat concentration as a noninvasive surrogate bioGmarker in the rabbit model of nonalcoholic fatty liver disease.DualGenergy CT derived material decomposition fat images can provide more diagnostic information at the early stage of NAFLD.
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The paper described the hemodynamics of blood flow based on fluid mechanics and its corresponding formulas, and revealed the limitation of blood flow velocity measurement for non-laminar flow when using the conventional pulse wave Doppler. The paper demonstrated the calculation of turbulence for blood flow based on velocity directions and quantified the turbulence according to the presented formulas. Two methods were introduced and the simulated results were analyzed. An example using real data based on ultrasound vector flow imaging for calculating the turbulence of blood flow was presented in the end.
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Blood Flow Velocity , UltrasonographyABSTRACT
Objective To investigate the relationship between the ratio of signal intensity of fluid-attenuated inversion recovery (FLAIR)sequence lesion side／contralateral side and the onset time of acute ischemic stroke. Methods Forty-three consecutive patients with acute ischemic stroke admitted to the Department of Neurology,Dongguan Hospital of Traditional Chinese Medicine from November 2016 to January 2018 were enrolled retrospectively. They were all first onset and were diagnosed by MRI,and the onset time was 0. 5 to 6. 0 h. According to the time window of effective rescue of the penumbra,43 patients were divided into a ≤4. 5 h group (n＝19)and a ＞4. 5-6. 0 h group (n＝24). The signal intensity values of FLAIR, diffusion-weighted imaging,signal intensity of apparent diffusion coefficient sequence on the lesion side and contralateral brain tissue in the two groups of patients were measured respectively,and the relative signal intensity (RSI)was calculated and compared between the two groups. Taking RSI as the dependent variable and onset time as the independent variable,a general linear regression analysis was performed. Results (1)In FLAIR sequence,the signal intensity value and RSI value of patients in the≤4. 5 h group were lower than those in the ＞4. 5-6. 0 h group. There were significant differences between the 2 groups (disease side signal intensity value:531 ± 109 vs. 681 ± 306,t ＝2. 04;RSI value:1. 19 ± 0. 13 vs. 1. 45 ± 0. 18,t＝5. 29,all P＜0. 05). There was no significant difference in the signal intensity values on the contralateral sides between the two groups (P＞0. 05). (2)In diffusion weighted imaging and apparent diffusion coefficient sequence,there were no significant differences in the signal intensity value and RSI value on the disease side and the contralateral side between the the≤4. 5 hours group and the ＞4. 5-6. 0 h group (all P＞0. 05). (3)In the FLAIR sequence,with the prolongation of the time of the disease,RSI gradually increased,and was positively correlated (r＝0. 756,P＜0. 01). Conclusions The quantitative measurement of the disease side／contralateral side of FLAIR sequence might reflect the onset time of acute ischemic stroke. Its RSI value increased with the prolonged onset time.
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Objective To measure the parameters of bronchus and peripheral pulmonary small vessel in the early simple pulmonary contusion, and to explore the changes of bronchial and pulmonary small blood vessels after pulmonary contusion.Methods The chest CT images of 30 patients with early simple pulmonary contusion were collected retrospectively,images were then automatically segmented using FACT-Digital lung TM software.Ipsilateral,contralateral bronchial parameters (luminal cross-sectional area,wall thickness,internal and external diameter,inner and outer circumference and luminal density)and pulmonary small vessel parameters (number of vessels in the visual area,total blood vessel area)for 33 pulmonary contusion cases were measured respectively,finally,correlation between lung contusion area and bronchial and small vessel parameters were analyzed.Results Ipsilateral bronchial parameters (luminal cross-sectional area, wall thickness,internal and external diameter,inner and outer circumference and luminal density)and pulmonary small vessel parameters (number of vessels in the visual area,total blood vessel area)were greater than those in the contralateral(P<0.05).The area of pulmonary contusion was not associated with bronchial parameters nor pulmonary small vessel parameters.Conclusion Quantitative CT analysis can intuitively show the changes of bronchial and pulmonary small blood vessels in patients with early simple pulmonary contusion.
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The current proxy indicators and quantitative strategy were summarized for cognitive reserve,the findings of cognitive reserve was discussed then in brain aging and Alzheimer's disease,and some future research directions were presented about cognitive reserve.The reserve of brain explains the disjunction between clinical symptoms and the degree of brain damage,whereby some people can tolerate more of age-related or Alzheimer's disease pathology than others and maintain brain function.The cognitive reserve hypothesis has been widely used in epidemiological and neuroimaging studies,but it lacks a unified quantitative indicator.The future research of cognitive reserve should be focused on the development of quantitative indicators that cover a variety of potential factors dynamically.
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The current proxy indicators and quantitative strategy were summarized for cognitive reserve,the findings of cognitive reserve was discussed then in brain aging and Alzheimer's disease,and some future research directions were presented about cognitive reserve.The reserve of brain explains the disjunction between clinical symptoms and the degree of brain damage,whereby some people can tolerate more of age-related or Alzheimer's disease pathology than others and maintain brain function.The cognitive reserve hypothesis has been widely used in epidemiological and neuroimaging studies,but it lacks a unified quantitative indicator.The future research of cognitive reserve should be focused on the development of quantitative indicators that cover a variety of potential factors dynamically.
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With developing technology, quantitative analysis of gait and balance has been much interested in last decade. In gait analysis, three-dimensional motions capture and gait analysis using foot pressure is widely used. For measuring balance, posturography with force plate especially dynamic intervention has been developed. Recently wearable device containing accelerometer and gyro-sensor can assess long term monitoring for real living situation beyond lab based environment. Future studies of validity and reliability of quantitative analysis is necessary for clinical implication.
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Foot , Gait , Postural Balance , Reproducibility of ResultsABSTRACT
Objective To investigate how the clinical laboratory conducting the verification of analytical measurement range (AM R) of quantitative items detected by the biochemical analyzer according to the requirements of the international standards by verifying the serum creatinine AMR for ensuring the accuracy and reliability of detection results .Methods The enzyme method was adopted to detect the 7‐concentration levels test specimens of CAP linear range proficiency test on the Roche Cobas 501 biochemical analyzer .These 7 specimens target values covered the low ,middle and high values of creatinine AMR marked by the manufacturer′s instructions .Each specimen was detected twice and the mean value was taken ,then the bias between the mean value and target value was calculated .In addition ,referring to the requirements of CLSI guiding document EP6‐P ,the patients′fresh serum contai‐ning high value creatinine was collected ,then mixed with certain proportion and centrifuged .The mixture concentration was calcu‐lated and served as the high value specimen(H) ,and the low value specimen was obtained by the same treatment .Then the high and low value specimens were dispensed with the relations of 5L ,4L+1H ,3L+2H ,2L+3H ,1L+4H and 5H and formed the series specimens .The creatinine levels in each specimen was detected on the Roche Cobas 501 biochemical analyzer ,each specimen was de‐tected 4 times .The obtained data were performed the regression analysis .Results The bias of 7‐level CAP specimen and target val‐ue was less than the allowable error ± 7 .5% [(1/2 × TE)% ] set by the clinical laboratory of the Beijing Sanfine Hopsital .The re‐gression equation of fresh mixed serums from patients was Y =0 .988 6X+16 .614 ,b=0 .988 6 ,between 0 .97 -1 .03 ,intercept a and 0 ,ta 0 .05 ,which showed no significant difference between intercept and 0 ,the regression line was through 0 point in fact .Conclusion The verification of creatinine AMR marked by the manufacturer′s instructions is passed ,which can be adopted by the clinical laboratory .
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The Bland-Altman method has been widely used for consistency evaluation in the field of medicine .However, fre-quent errors in the application of the method seriously affect the quality of researches .This review focuses on the studies of the Bland-Altman method , the status quo and common problems in its application , and standards for related reports .
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Objective To evaluate the diagnostic and staging value of orbital structures quantitative measurement with 3T mag-netic resonance imaging in patients with Graves’ophthalmopathy (GO).Methods Twenty-three GO patients (patient group)and eighteen healthy volunteers (contrast group)were enrolled.Quantitative measurement of orbital structures including exophthalmos values,fatty tissue thickness of the inner side of eye balls,cross-sectional areas of extraocular muscles and signal intensity ratios of extraocular muscles to the ipsilateral temporal muscles (SIR values),and they were compared between two groups.Correlations be-tween the quantitative values and clinical active score (CAS)were accessed.Receiver operating characteristic (ROC)analysis was performed to evaluate the most relevant quantitative parameter and its diagnostic value in discriminating active from inactive GO pa-tients.Results There were significant differences between the GO group and contrast group regarding to all the quantitative parame-ters (P <0.05).Strong correlation was found between SIR values and CAS (r =0.730,P <0.001 ).Significant difference of SIR was found between patients with active GO and inactive GO (P =0.002),and a cut off value of 3.25 might be the critical threshold value,with diagnostic sensitivity of 81.8% and specificity of 83.3% respectively.Conclusion Quantitative measurement of orbital structures with 3T MR imaging could provide assistant in diagnosing and staging of GO.
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Objective To discuss the setting problem of control limit for quality control chart during the statistical quality con-trol procedure of clinical laboratory quantitative measurement.Methods The normality test of the monthly quality control data for 3 items of albumin (ALB),alanine aminotransferase (ALT)and creatinine (Cr)was performed by using the SPSS 14.0 statistical software and which was compared with the cumulated data.Results Among 30 groups of data,the normality test was inconformity in 18 groups,among 30 groups of mean t test,the differences in 20 groups showed statistical significance(P <0.05).Therefore,the calculated means and standard deviation(SD)in short term could not be directly set as the control limit of the quality control chart. Conclusion Setting the control limit of internal quality control in clinical laboratory quantitative measurement should be according to the guidance of C24-A3 document in CLSI.The SD estimated value obtained from large amount stable quality control data or the 6-month cumulative values is recommended to be used as SD of the new batch number,which should be regularly assessed.
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Objective To design and optimize the MRS pulse sequence which used to measure gamma-aminobutyric acid(GABA) in vivo. Methods In-depth research for the MRS sequence was carried out and a theoretical analysis and simulation by software using product-operator algebra for the design and optimization of pulse sequence was discussed. Results Through the simulation of MRUI software, Cr signal at ?3.0 was seen to be suppressed and the weak GABA signal was displayed clearly. Conclusion The sequence was designed and optimized. Method to increase the efficiency and the stability of the measurement was studied. Our research gives theoretical preparation for the coming programming work.
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Phase contrast magnetic resonance imaging techniques can be used to evaluate the to-and-fro motion of cerebrospinal fluid(CSF) throughout CSF pathways between the ventricles and subarachnoid space of the brain and spine. This CSF motion is due to transmitted cardiac pulsation from systolic expansion of the cerebral hemispheres. To cover the entire cardiac cycle, peripheral cardiac triggering was used. Using this technique, we analyzed quantitative CSF motion over a cardiac cycle to distinguish normal CSF flow from that seen in hydrocephalus. We tested the reproducibility of the aqueductal CSF signal intensity on a phase contrast cine MR sequence in 28 patients with normal ventricle. Sixteen patients with obstructive hydrocephalus and 11 patients with normal pressure hydrocephalus(NPH) were investigated with the sequence before and after CSF diversion. The peak CSF flow velocity in aqueduct was significantly increased in patients with NPH and significantly decreased in patients with obstructive hydrocephalus(NPH group: 6.71cm/sec, control group: 2.94cm/sec, obstructive group; less than 1.0cm/sec). After LP shunting in NPH group, retrograde flow signal curves were anterogradely converted and the peak flow velocities were somewhat decreased(mean: 5.10cm/sec). The clinical diagnosis of NPH was well correlated with the results of cine MRI. After endoscopic third ventriculostomy in obstructive group, we could note increased CSF flow velocity both at prepontine cistern and precordal subarachnoid space with markedly increased flow at prepontine cistern. Phase contrast cine MRI is useful in evaluatng the CSF dynamics in patients with hyperdynamic aqueductal CSF (NPH) or aqueductal obstruction(obstructive hydrocephalus).
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Humans , Brain , Cerebrospinal Fluid , Cerebrum , Diagnosis , Hydrocephalus , Magnetic Resonance Imaging , Magnetic Resonance Imaging, Cine , Spine , Subarachnoid Space , VentriculostomyABSTRACT
0.05). It suggested that the 3 D quantitative measurement is a useful technique for the diagnosis of diseases in the base of the middle cranial fossa region,so that it is useful for surgical planning.