Objective:To explore the feasibility of 60 kV low-dose scanning technique on chest combined with ClearInfinity deep learning reconstruction algorithm in the diagnosis of pediatric mycoplasma pneumonia.Methods:A total of 132 pediatric patients,who admitted to Taihe Hospital Affiliated to Hubei Medical College and were diagnosed as mycoplasma pneumonia,were selected,and all of them underwent computed tomography(CT)scans on chest.They were randomly divided into routine dose group(66 cases),low dose ClearView and ClearInfinity group(66 cases).In the routine dose group,the tube voltage of CT scan on chest was 100 kV,and 50%ClearView iterative algorithm was adopted in this group.The tube voltage of CT scan on chest was 60kV in low dose ClearView and ClearInfinity group,and 50%ClearView iterative algorithm and 50%ClearInfinity deep learning reconstruction algorithm were used respectively to conduct reconstruction.The difference of radiation dose among the three groups was compared.The CT values and standard deviation(SD)values,signal-to-noise ratio(SNR)and contrast-to-noise ratio(CNR)of the region of interest(ROI)of the images of 3 groups were measured and calculated.The images were subjectively evaluated by two diagnostic attending physicians with 10 years of work experience,and the Kappa test was adopted to analyze the consistency of the score results.Results:Compared with the routine dose group,the volume CT dose index(CTDIvol)values,dose-length product(DLP)values and effective radiation dose(ED)values of the low dose ClearView group and ClearInfinity group reduced respectively by 87.58%,87.24%and 88.00%,and the differences were statistically significant(t=4 584.07,63.73,61.27,P<0.01).The noise values of left and right lung of the routine dose group were significantly lower than those of the low dose ClearView group,while were significantly higher than those of ClearInfinity group,and the differences were significant(Z=-9.912,-7.013,P<0.01),and the difference of them between low dose ClearView group and ClearInfinity group was significant(Z=-9.912,P<0.01).The SNR and CNR of left and right lung of low dose ClearView group were significantly lower than those of the routine dose group,with statistically significant(t=-34.810,5.522,P<0.01),while these of the low dose ClearInfinity group were significant higher than them of the routine dose group(t=3.544,-8.674,P<0.05),respectively.The two attending physicians had favorable consistency in the subjective evaluation for images(Kappa>0.75,P<0.01).The subjective score of the routine dose group was not significantly different with that of the low dose ClearInfinity group(P>0.05),but was significantly better than that of the low dose ClearView group(Z=-6.425,P<0.01).Conclusion:For pediatric patients with mycoplasma pneumonia,the 60 kV low dose CT on chest combined with ClearInfinity deep learning reconstruction algorithm can ensure image quality on the premise of reducing radiation,which can ensure the diagnostic effect.

Objective To investigate the changes of microstructure and blood perfusion of thalamus and basal ganglia in patients with untreated depressive disorder using diffusion kurtosis imaging (DKI) and three-dimensional arterial spin labeling (3D ASL) perfusion imaging.Methods Totally 21 untreated patients with depressive disorder (disease group) and 32 healthy volunteers (control group) underwent DKI,3D ASL and routine MR scanning were enrolled.DKI parameters (mean kurtosis [MK],axial kurtosis [Ka],radial kurtosis [Kr],fractional anisotropy [FA],mean diffusivity [MD],axial diffusivity [Da] and radial diffusivity [Dr]) and 3D ASL parameters (cerebral blood flow [CBF]) of bilateral heads of caudate nucleus,thalamus and putamens were measured and compared between the 2 groups.Results Compared with control group,Ka of left caudate head in disease group was significantly higher,while Kr was significantly lower (both P＜ 0.05).Ka of right putamens in disease group was significantly higher than that in control group (P＜0.05).Compared with control group,CBF of left caudate head and bilateral putamens decreased significantly in disease group (all P＜0.05).Conclusion Untreated depressed patients show abnormal DKI parameters and blood perfusion in basal ganglia,which indicating that microstructure integrity is impaired and blood perfusion decreases.The abnormalities in basal ganglia microstructure and blood perfusion may serve as one of the neuroimaging features of depressive disorders.

Objective To observe the impact of walking,running and stair activity on knee meniscus with T1 rho and T2 mapping sequences.Methods Twenty-three participants immediately after 30 minutes of rest,walking,running and stair activity underwent MRI scanning of the right knee,respectively.The 30 minutes rest was conducted before every physical activity.The physical activities were performed randomly to every participant in the morning every other week.T1 rho andT2 values of the meniscus in different physiological activities were estimated.Results T1 rho and T2 values reduced after physiological activities in posterior horn,body of medial meniscus and body of lateral meniscus compared with those of rest state (all P＜50.05).Compared with rest,reduction rate of T1 rho and T2 values of medial meniscus after different physiological activities reduced in the following order:Posterior horn ＞ body ＞ anterior horn,while those of lateral meniscus reduced in the following order:Body ＞ posterior horn ＞ anterior horn.Conclusion T1 rho and T2 mapping sequences are sensitive technologies to monitor the impacts of different activities on knee meniscus.

Objective To explore the role of MRI(T1ρ)in the early osteoarthritis,curative efficacy monitoring and speculated that the mechanism of curative effect.Methods (1)(early OA model)A total of 28 New Zealand white rabbits were randomly divided into A,B,C three groups.group A(treatment)and B(control)were both for 1 1 rabbits,and 6 rabbits were considered as blank control group(group C).0.5 mL 1.6% papain was injected into the right knee joint cavity both group A and B according to three times (1,4,7 days).The equivalent dilution was injected into the left knee joint cavity simultaneously.3 weeks after the first injection,and T2 WI,3D-FS-SPGR,and T1ρ mapping in sagittal plain were scanned for three groups.Randomly selected two models pathology test in the group A and B,confirm early OA model is established.(2)(treat models)Then give epimedium lavage to group A two month.The equivalent sterile saline lavage to group B.A certain time (T0 = 0,T1 = 1 mon,T2 = 2 mon)after treated do MR scanned for group A and B.Analysis of the image.T1ρvalues and the cartilage thickness in bilateral femoral condyle cartilage were measured by post-processing software.The all femurs were pathological examined.T1ρvalues and the cartilage thickness were statistic analysis. Results (1)Articular cavity injection of papain can successfully establish early osteoarthritis rabbit model which pathology has been confirmed.T1ρvalues of the experimental (group A,B)were significant higher than of the control side(P<0.05).Cartilage thickness values of the experimental (group A,B)and the control side has no statistical significance(P >0.05).(2)T1ρvalues of the Epimedium treat model (right side)were significant lower than of the pre-treatment that of the preintervention (P <0.05 ).T1ρvalues of the NS treatment (left side)and the pre-treatment has no statistical significance(P>0.05).Conclusion (1)T1ρvalues of the early and advanced stage of OA had increased in various degree,and the values related cartilage matrix composition.(2 )Single herb Epimedium has effective to treat early stages osteoarthritis in knee joint.Spec-ulated that the possible mechanism for treatment common channel in the development of OA,which inhibition protease formation and promote proteoglycan secretion.

Objective To evaluate MR relaxometry techniques and dual-energy X-ray absorptiometry (DXA) for the diagnosis of osteoporotic diseases in rats. Methods Thirty 3-month-old female rats were randomly divided (using completely randomized grouping method) into two groups (each contained 15 rats). Animals in group A without osteoporotic castration were included as normal controls, whereas osteoporotic castration was created in each animal in group B. Three parameters (BMC, BMD, Hbmdl)was measured for both groups by DXA at two time points, one immediately before the castration and another at the 12 th week after the castration. Then animals from the control group and the osteoporotic group went through the following three diagnostic procedures using a 1.5 T MR system: (1) A fast multi echo gradient echo (MEGRE) pulse train sequence with different inter-echo intervals (1000, 500, 400, 300, 200, 100) to obtain the T_2~* value. (2) A multi-echo fast spin echo sequence to obtain the T_2map. (3) A conventional spin-echo (CSE) sequence to obtain the T_1map. The statistical difference between group A and group B was tested by t-test to analyze parameters. And, the most significant parameter for diagnosis ofosteoporotic diseases was picked out from all parameters by Fisher Sequential diseriminant analysis. At the end of experiments, animals were killed and histopathological examination was performed on the femurs of animals from both control and osteoporotic groups. Results (1) Histopathological examination confirmed the presence of osteoperosis in all animals in group B. (2) BMD was picked out from 3 DXA parameters (BMC,BMD,Hbmdl) by fisher stepwise discriminant analysis, and its discriminant rates was 87.6%. (3) All 2-sample t-test results(t=6.20, 4.79, 5.18, 5.22, 5.59, 4.37, 6.14, 5.12, 5.09, 4.99, 5.57, 4.84, 4.07, 2.98, 6.75 individually) for MR relaxometry parameters(T_2~* 1000,R_2~* 1000,T_2~* 500,R-2~* 500,T_2~* 400,R_2~* 400,T_2~* 300,R_2~* 300,T_2~* 200, R_2~* 200, T_2~* 100, R_2~* 100, T_2map, R_2map, T_1map) showed statistically significant differences between groups A and B (P=0.01 for T_2~* map, P=0.00 for all other parameters) except the R_2map(P=0.07). (4) Using fisher stepwise discriminafion method in the analysis of 14 parameters of MR relaxometry techniques and 3 parameters of dual X-ray absorptiometry(T_2~* 1000,T_2~* 500,T_2~* 400,T_2~* 300,T_2~* 200,T_2~* 100,T_2map, R_2~* 1000, R_2~* 500, R_2~* 400, R_2~* 300, R_2~* 2OO, R_2~* 100,T_1map,BMC,BMD,Hbmdl), we found that the most significant difference was from the T_2map and T_1map. Conclusions The MR relaxometry parameter-T_2map in the present study is shown to be appropriate parameter for the diagnosis of osteoperotie diseases, and stability of magnetic field plays an important role in this process. It would be the optimal method to make a diagnosis of osteoporotic diseases with both MR relaxometry and DXA technological means.

Objective To study the value of diffusion tensor imaging(DTI) in early assessment of prognosis of hypoxic-ischemicencephalopathy(HIE) in new infants. Methods 96 cases of full term infants with HIE underwent DTI examinations at 0～12 days and 6～36 months. Based on clinical diagnostic criteria, 96 cases were divided into three groups: mild, moderate and severe HIE groups. Fractional anisotropy(FA) values in the corpus callosum splenium and the posterior limb of internal capsules were measured. Results (1) Varying degrees of FA groups was significantly different from the same site, increased linearly with time,but the magni-tude of change was different;(2)When FA value of corpus callosum splenium in the cut-off point was ≥0.437,the sensitivity(SE) was 83.8% , the specificity(SP) was 18.6% , ROC area under the curve was 0.903 , 95% confidence interval was from 0.846 to 0.961,standard error was 0.029;when FA value of posterior limb of internal capsule in the cut-off point ≥0.391,SE was 86.5%, SP was 11.9% ,ROC area under the curve was 0.940,95% confidence interval was from 0.898 to 0.984,standard error was 0.022. Conclusion MR DTI examination is of significant value in evaluating early the prognosis of HIE in infants.

0.05). Conclusions DTI is valuable in assessing the directionality and density of white matter and can reflect the age-related physiological changes of white matter in vivo non- invasively.

Objective To compare with the advantage or shortage of several scan series in imaging of normal articular cartilage in knee.The MR manifestation were observed and thickness of different location of cartilage in knee in different series were calulated.Methods The knees of 30 healthy volunteers were imaged with five different MR imaging sequences including T 1-weighted,proton density-weighted,T 2-weighted FSE,STIR and 3D-FS-SPGR.The value of CNR were determined for cartilage versus a saline fluid phantom,marrow fat,and muscle.The MR 2D and 3D manifestation were observed and thickness of different location of cartilage in knee in different series were calculated.Results The value of CNR of 3D-FS-SPGR for cartilage versus a saline fluid phantom,marrow fat,and muscle were compared with other sequences and were significantly different.The values of cartilage thickness with 3D-FS-SPGR were more than those with other series.The mulplaner appearance was observed.There was five-plane manifestation when cartilage thickness was more than 4 mm.The value of cartilage thickness of male and female were 2.63 mm and 2.52 mm,respectively.Conclusion 3D-FS-SPGR sequences have significant advantage compared with other series in imaging normal articular cartilage of knee.The cartilage is show clearly than other sequences.The value of cartilage thickness with 3D-FS-SPGR is more accurate.Moreover it can also provide much information adding to 3D construction of cartilage.

Objective To study the roles of isotropic diffusion weighted imaging and apparent diffusion coefficients (ADC) mapping in diagnosing cerebral infarction, monitoring the development of cerebral infarction and defining the infarction stages.Methods 86 work-ups in 70 patients with cerebral infarction (8 hyperacute, 13 acute, 32 subacute, 11 steady, and 22 chronic) were imaged with both conventional MRI and single-shot echo-planar isotropic diffusion weighted imaging.The change of the infarct lesion in DWI and T_2WI was also analyzed.The average ADC, relative ADC (rADC), and the ADC from center to periphery of the lesion were calculated.Results 8 hyperacute cerebral ischemic regions were revealed at DWI and ADC mapping.Hyperacute and acute infarcts appeared as areas of hyperintensity on DWI, and their average ADC was significantly depressed compared with that of homologous contralateral tissue [(0.698?0.104) ?10 -3 mm 2/s versus (0.990?0.161)?10 -3 mm 2/s; t=-14.372, P

Objective To study the follow-up value of MRI in the sequela hypoxic-ischemic encephalopathy(HIE).Methods MRI features of HIE in 81 neonates were analyzed retrospectively,every child had two cranial MRI scans,the first scan at the end of the newborn stage,the second scan at 4 months to 4 years.There were 66 full-term neonates and 15 preterm neonates.Results Of 81 cases,79 cases were abnormal on second MRI examination,including myelinogenetic abnormal in 59 cases(72.8%),external hydrocephalus(EH) in 53 cases(65.4%),brain malacia in 26 cases(32.1%),cerebaral atrophy in 25 cases(30.1%),white matter decrease in 24 cases(29.6%) and dysplasia of corpus callosum in 9 cases(11.1%).EH(26/35cases) and myelinogenetic abnormal(16/35 cases) in mild HIE group,brain malacia(12/29 cases) in moderate HIE group,cerebaral atrophy(16/17 cases) and white matter decrease(15 /17 cases)in severe HIE group were often seen.Conclusion MRI findings can reflect the pathological changes of sequela of HIE,and provide objective basis for diagnosis and assessment of prognosis.