Objective To investgate the value of various parameters obtained from monoexponential,biexponential,and stretched exponential diffusion-weighted imaging models in the differential diagnosis of breast lesions.Methods A...Objective To investgate the value of various parameters obtained from monoexponential,biexponential,and stretched exponential diffusion-weighted imaging models in the differential diagnosis of breast lesions.Methods A retrospective study was performed in 54 patients with pathologically confirmed malignant tumors(n=30),benign lesions(n=34)and normal fibroglandular展开更多
Background：Diffusion weighted imaging （DWI）,with the applying of intravoxel incoherent motion model,has showed promising results in obtaining additional information about microperfusion and tubular flow associated ...Background：Diffusion weighted imaging （DWI）,with the applying of intravoxel incoherent motion model,has showed promising results in obtaining additional information about microperfusion and tubular flow associated with morphologic changes in chronic kidney diseases.The study aims to evaluate the potential of T2-weighted signal intensity （SI） and DWI with mono-and bi-exponential models to reflect the serial changes on cisplatin （CP） induced rat renal fibrosis models.Methods：Magnetic resonance exams were performed prior to and 2nd day,4th day,6th day,8th day,2nd week,3rd week and 4th week after CP injection at a 3.0T with an animal coil.Besides T2-weighted images （T2WI）,DWI of 13 b values from 0 to 1500 s/mm^2 was acquired.Apparent diffusion coefficient （ADC）,fluid fraction f,pure diffusivity D and pseudodiffusivity D＊ values were calculated.The regions of interest were placed on cortex （CO）,outer stripe of the outer medulla （OM） and inner stripe of the outer medulla （OM）,parameters were measured and compared among different time points.Five rats were scarified at each time point for pathological examination.Results：OM revealed remarkable hyperintense and broadened before it became an obscure thread,while CO demonstrated moderate hyperintense and IM didn＇t show significant change on T2WI.On all three stripes,ADC values decreased firstly then kept increasing since the 4th day;f values decreased on all stripes; D values had a tendency to increase with fluctuations but the changes didn＇t achieve statistical significance; D＊ values increased at the 2nd day then tended to be steady thereafter.Pathological findings revealed tubules epitheliums swelling followed by inflammation cells infiltration,interstitial fibrosis was observed since the 2nd week.Conclusions：All of T2-weighted SI,ADC,and biexponential models parameters vary during fibrotic process; biexponential model is superior to monoexponential model in separating changes of microperfusion together with tubular flow from pure diffusion.展开更多
With the substantial increase in image transmission,the demand for image security is increasing.Noise-like images can be obtained by conventional encryption schemes,and although the security of the images can be guara...With the substantial increase in image transmission,the demand for image security is increasing.Noise-like images can be obtained by conventional encryption schemes,and although the security of the images can be guaranteed,the noise-like images cannot be directly previewed and retrieved.Based on the rank-then-encipher method,some researchers have designed a three-pixel exact thumbnail preserving encryption(TPE2)scheme,which can be applied to balance the security and availability of images,but this scheme has low encryption efficiency.In this paper,we introduce an efficient exact thumbnail preserving encryption scheme.First,blocking and bit-plane decomposition operations are performed on the plaintext image.The zigzag scrambling model is used to change the bit positions in the lower four bit planes.Subsequently,an operation is devised to permute the higher four bit planes,which is an extended application of the hidden Markov model.Finally,according to the difference in bit weights in each bit plane,a bit-level weighted diffusion rule is established to generate an encrypted image and still maintain the same sum of pixels within the block.Simulation results show that the proposed scheme improves the encryption efficiency and can guarantee the availability of images while protecting their privacy.展开更多
AIM To develop a novel rat model of heterogeneous hepatic injury.METHODS Seventy male Sprague-Dawley rats were randomly divided into a control group(n = 10) and a colchicine group(n =60). A 0.25% colchicine solution(0...AIM To develop a novel rat model of heterogeneous hepatic injury.METHODS Seventy male Sprague-Dawley rats were randomly divided into a control group(n = 10) and a colchicine group(n =60). A 0.25% colchicine solution(0.4 mL/kg) was injected via the splenic vein in the colchicine group to develop a rat model of heterogeneous hepatic injury. An equal volume of normal saline was injected via the splenic vein in the control group. At days 3, 7, and 14 and weeks 4, 8, and 12 after the operation, at least seven rats of the colchicine group were selected randomly for magnetic resonance imaging(MRI) examinations, and then they were euthanized. Ten rats of the control group underwent MRI examinations at the same time points, and then were euthanized at week 12. T2-weighted images(T2 WI) and diffusion weighted imaging(DWI) were used to evaluate the heterogeneous hepatic injury. The heterogeneous injury between the left and right hepatic lobes was assessed on liver sections according to the histological scoring criteria, and correlated with the results of MRI study. RESULTS Obvious pathological changes occurred in the hepatic parenchyma in the colchicine group. Hepatic injury scores were significantly different between the left and right lobes at each time point(P < 0.05). There was a significant difference in apparent diffusion coefficient(ADC) of DWI and liver-to-muscle ratio(LMR) of T2 WI between the left and right lobes of rats in the colchicine group(P < 0.05) at each time point, and similar results were observed between the colchicine and control groups. Besides, there was a significant correlation between hepatic injury scores and ADC values or LMR(r =-0.682, P = 0.000; r =-0.245, P = 0.018).CONCLUSION Injection with colchicine via the splenic vein can be used to successfully develop a rat model of heterogeneous hepatic injury. DWI and T2 WI may help evaluate the heterogeneous injury among liver lobes.展开更多
文摘Objective To investgate the value of various parameters obtained from monoexponential,biexponential,and stretched exponential diffusion-weighted imaging models in the differential diagnosis of breast lesions.Methods A retrospective study was performed in 54 patients with pathologically confirmed malignant tumors(n=30),benign lesions(n=34)and normal fibroglandular
基金This work was supported by grant from Chinese Nature Science Foundation （No. 81171316）.
文摘Background：Diffusion weighted imaging （DWI）,with the applying of intravoxel incoherent motion model,has showed promising results in obtaining additional information about microperfusion and tubular flow associated with morphologic changes in chronic kidney diseases.The study aims to evaluate the potential of T2-weighted signal intensity （SI） and DWI with mono-and bi-exponential models to reflect the serial changes on cisplatin （CP） induced rat renal fibrosis models.Methods：Magnetic resonance exams were performed prior to and 2nd day,4th day,6th day,8th day,2nd week,3rd week and 4th week after CP injection at a 3.0T with an animal coil.Besides T2-weighted images （T2WI）,DWI of 13 b values from 0 to 1500 s/mm^2 was acquired.Apparent diffusion coefficient （ADC）,fluid fraction f,pure diffusivity D and pseudodiffusivity D＊ values were calculated.The regions of interest were placed on cortex （CO）,outer stripe of the outer medulla （OM） and inner stripe of the outer medulla （OM）,parameters were measured and compared among different time points.Five rats were scarified at each time point for pathological examination.Results：OM revealed remarkable hyperintense and broadened before it became an obscure thread,while CO demonstrated moderate hyperintense and IM didn＇t show significant change on T2WI.On all three stripes,ADC values decreased firstly then kept increasing since the 4th day;f values decreased on all stripes; D values had a tendency to increase with fluctuations but the changes didn＇t achieve statistical significance; D＊ values increased at the 2nd day then tended to be steady thereafter.Pathological findings revealed tubules epitheliums swelling followed by inflammation cells infiltration,interstitial fibrosis was observed since the 2nd week.Conclusions：All of T2-weighted SI,ADC,and biexponential models parameters vary during fibrotic process; biexponential model is superior to monoexponential model in separating changes of microperfusion together with tubular flow from pure diffusion.
基金supported by the Pre-research Project of Songshan Laboratory,China(No.YYJC012022011)the Postgraduate Education Reform and Quality Improvement Project of Henan Province,China(Nos.YJS2022JD26 and SYLAL2023020)+2 种基金the Postgraduate Education Innovation Training Base,China(No.SYLJD2022008)the Science and Technology Project of Henan Province,China(Nos.232102210109 and 232102210096)the Open Foundation of Henan Key Laboratory of Cyberspace Situation Awareness,China(No.HNTS2022019)。
文摘With the substantial increase in image transmission,the demand for image security is increasing.Noise-like images can be obtained by conventional encryption schemes,and although the security of the images can be guaranteed,the noise-like images cannot be directly previewed and retrieved.Based on the rank-then-encipher method,some researchers have designed a three-pixel exact thumbnail preserving encryption(TPE2)scheme,which can be applied to balance the security and availability of images,but this scheme has low encryption efficiency.In this paper,we introduce an efficient exact thumbnail preserving encryption scheme.First,blocking and bit-plane decomposition operations are performed on the plaintext image.The zigzag scrambling model is used to change the bit positions in the lower four bit planes.Subsequently,an operation is devised to permute the higher four bit planes,which is an extended application of the hidden Markov model.Finally,according to the difference in bit weights in each bit plane,a bit-level weighted diffusion rule is established to generate an encrypted image and still maintain the same sum of pixels within the block.Simulation results show that the proposed scheme improves the encryption efficiency and can guarantee the availability of images while protecting their privacy.
基金Supported by the Chinese National Natural Science Foundation,No.81471719
文摘AIM To develop a novel rat model of heterogeneous hepatic injury.METHODS Seventy male Sprague-Dawley rats were randomly divided into a control group(n = 10) and a colchicine group(n =60). A 0.25% colchicine solution(0.4 mL/kg) was injected via the splenic vein in the colchicine group to develop a rat model of heterogeneous hepatic injury. An equal volume of normal saline was injected via the splenic vein in the control group. At days 3, 7, and 14 and weeks 4, 8, and 12 after the operation, at least seven rats of the colchicine group were selected randomly for magnetic resonance imaging(MRI) examinations, and then they were euthanized. Ten rats of the control group underwent MRI examinations at the same time points, and then were euthanized at week 12. T2-weighted images(T2 WI) and diffusion weighted imaging(DWI) were used to evaluate the heterogeneous hepatic injury. The heterogeneous injury between the left and right hepatic lobes was assessed on liver sections according to the histological scoring criteria, and correlated with the results of MRI study. RESULTS Obvious pathological changes occurred in the hepatic parenchyma in the colchicine group. Hepatic injury scores were significantly different between the left and right lobes at each time point(P < 0.05). There was a significant difference in apparent diffusion coefficient(ADC) of DWI and liver-to-muscle ratio(LMR) of T2 WI between the left and right lobes of rats in the colchicine group(P < 0.05) at each time point, and similar results were observed between the colchicine and control groups. Besides, there was a significant correlation between hepatic injury scores and ADC values or LMR(r =-0.682, P = 0.000; r =-0.245, P = 0.018).CONCLUSION Injection with colchicine via the splenic vein can be used to successfully develop a rat model of heterogeneous hepatic injury. DWI and T2 WI may help evaluate the heterogeneous injury among liver lobes.
