AIM:To evaluate the feasibility of low contrast medium and radiation dose for hepatic computed tomography(CT) perfusion of rabbit VX2 tumor.METHODS:Eleven rabbits with hepatic VX2 tumor underwent perfusion CT scanning...AIM:To evaluate the feasibility of low contrast medium and radiation dose for hepatic computed tomography(CT) perfusion of rabbit VX2 tumor.METHODS:Eleven rabbits with hepatic VX2 tumor underwent perfusion CT scanning with a 24-h interval between a conventional tube potential(120 k Vp) protocol with 350 mg I/m L contrast medium and filtered back projection,and a low tube potential(80 k Vp) protocol with 270 mg I/m L contrast medium with iterative reconstruction.Correlation and agreement among perfusion parameters acquired by the conventional and low dose protocols were assessed for the viable tumor component as well as whole tumor.Image noise and tumor-to-liver contrast to noise ratio during arterial and portal venous phases were evaluated.RESULTS:A 38% reduction in contrast medium dose(360.1 ± 13.3 mg I/kg vs 583.5 ± 21.5 mg I/kg,P < 0.001) and a 73% decrease in radiation dose(1898.5 m Gy·cm vs 6951.8 m Gy·cm) were observed.Interestingly,there was a strong positive correlation in hepatic arterial perfusion(r = 0.907,P < 0.001;r = 0.879,P < 0.001),hepatic portal perfusion(r = 0.819,P = 0.002;r = 0.831,P = 0.002),and hepatic blood flow(r = 0.945,P < 0.001;r = 0.930,P < 0.001) as well as a moderate correlation in hepatic perfusion index(r = 0.736,P = 0.01;r = 0.636,P = 0.035) between the low dose protocol with iterative reconstruction and the conventional protocol for the viable tumor component and the whole tumor.These two imaging protocols provided a moderate but acceptable agreement for perfusion parameters and similar tumorto-liver CNR during arterial and portal venous phases(5.63 ± 2.38 vs 6.16 ± 2.60,P = 0.814;4.60 ± 1.27 vs 5.11 ± 1.74,P = 0.587).CONCLUSION:Compared with the conventional protocol,low contrast medium and radiation dose with iterative reconstruction has no significant influence on hepatic perfusion parameters for rabbits VX2 tumor.展开更多
Objective To evaluate the feasibility of using a low concentration of contrast medium （Visipaque 270 mgl/mL）, low tube voltage, and an advanced image reconstruction algorithm in head and neck computed tomography ang...Objective To evaluate the feasibility of using a low concentration of contrast medium （Visipaque 270 mgl/mL）, low tube voltage, and an advanced image reconstruction algorithm in head and neck computed tomography angiography （CTA）. Methods Forty patients （22 men and 18 women; average age 48.7 ± 14.25 years; average body mass index 23.9 ± 3.7 kg/m^2） undergoing CTA for suspected vascular diseases were randomly assigned into two groups. Group A （n = 20） was administered 370 mgl/mL contrast medium, and group B （n = 20） was administered 270 mgl/mL contrast medium. Both groups were administered at a rate of 4.8 mL/s and an injection volume of 0.8 mL/kg. Images of group A were obtained with 120 kVp and filtered back projection （FBP） reconstruction, whereas images of group B were obtained with 80 kVp and 80% adaptive iterative statistical reconstruction algorithm （ASiR）. The CT values and standard deviations of intracranial arteries and image noise on the corona radiata were measured to calculate the contrast-to-noise ratio （CNR） and signal-to-noise ratio （SNR）. The beam-hardening artifacts （BHAs） around the skull base were calculated. Two readers evaluated the image quality with volume rendered images using scores from 1 to 5. The values between the two groups were statistically compared. Results The mean CT value of the intracranial arteries in group B was significantly higher than that in group A （P 〈 0.001）. The CNR and SNR values in group B were also statistically higher than those in group A （P 〈 0.001）. Image noise and BHAs were not significantly different between the two groups. The image quality score of VR images of in group B was significantly higher than that in group A （P = 0.001）. However, the quality scores of axial enhancement images in group B became significantly smaller than those in group A （P〈 0.001）. The CT dose index volume and dose-length product were decreased by 63.8% and 64%, respectively, in group B （P 〈 0.001 for both）. Conclusion Visipaque combined with 80 kVp and 80% ASiR provided similar image quality in intracranial CTA with 64% radiation dose reduction compared with the use of lopamidol, 120 kVp, and FBP reconstruc-tion.展开更多
Text extraction is the key step in the character recognition;its accuracy highly relies on the location of the text region. In this paper, we propose a new method which can find the text location automatically to solv...Text extraction is the key step in the character recognition;its accuracy highly relies on the location of the text region. In this paper, we propose a new method which can find the text location automatically to solve some regional problems such as incomplete, false position or orientation deviation occurred in the low-contrast image text extraction. Firstly, we make some pre-processing for the original image, including color space transform, contrast-limited adaptive histogram equalization, Sobel edge detector, morphological method and eight neighborhood processing method (ENPM) etc., to provide some results to compare the different methods. Secondly, we use the connected component analysis (CCA) method to get several connected parts and non-connected parts, then use the morphology method and CCA again for the non-connected part to erode some noises, obtain another connected and non-connected parts. Thirdly, we compute the edge feature for all connected areas, combine Support Vector Machine (SVM) to classify the real text region, obtain the text location coordinates. Finally, we use the text region coordinate to extract the block including the text, then binarize, cluster and recognize all text information. At last, we calculate the precision rate and recall rate to evaluate the method for more than 200 images. The experiments show that the method we proposed is robust for low-contrast text images with the variations in font size and font color, different language, gloomy environment, etc.展开更多
Background: Chronic kidney disease patients are at a greater risk for nephropathy requiring dialysis after percutaneous coronary intervention. Such patients are usually deferred due to fear of “Renalism”.?Objectives...Background: Chronic kidney disease patients are at a greater risk for nephropathy requiring dialysis after percutaneous coronary intervention. Such patients are usually deferred due to fear of “Renalism”.?Objectives This study assesses the outcome of Low dose contrast protocol during PCI in CKD patients whose e-GFR 60 ml/min/1.72 m and investigates a safety margin for contrast use in these high-risk categories.?Methods: Patients were into three groups according to CV/e-GFR ratio: Group (A) low-dose: CV/e-GFR ratio 2.0 Group (B) medium-dose: CV/e-GFR ratio > 2.0 and × bodyweight\s.creatinine). Group (C) high-dose: CV/e-GFR ratio > MACD. Results: A total of 73 patients were enrolled. Average age was 54 ± 8 years,81.4% were male and 18.6% were females and 52% were diabetic. Mean baseline e-GFR was 40 ± 8.0 ml/min/1.73m2. Contrast Volume used in group A was (58.26 ± 15.05) (n = 24), in group B (109.42 ± 17.11) (n = 26) and in group C (304.5 ± 60.30) (n = 23), respectively. The incidences of CI-AKI in the 3 groups were 0%, 11.5% and 35%, respectively (p = 0.02). All-cause death 0%, 17% and introduction of maintenance hemo dialysis was 0%, 11.5% and 26%, respectively (p Conclusion: Low dose contrast protocol is safe, effective and easily applicable technique without CI-AKI or death.展开更多
目的探讨高频超声造影(CEUS)在浅表肝脏局灶性病变(FLLs)检出及诊断中的临床价值。方法选取我院浅表FLLs患者38例,共63个病变,分别使用低频凸阵探头和高频线阵探头对患者进行CEUS检查,比较低频CEUS与高频CEUS在病变可见度评分、检出率...目的探讨高频超声造影(CEUS)在浅表肝脏局灶性病变(FLLs)检出及诊断中的临床价值。方法选取我院浅表FLLs患者38例,共63个病变,分别使用低频凸阵探头和高频线阵探头对患者进行CEUS检查,比较低频CEUS与高频CEUS在病变可见度评分、检出率和良恶性鉴别诊断中的差异。结果浅表FLLs在高频CEUS下平均可见度评分和检出率分别为(3.62±0.79)分、93.7%(59/63),均显著高于低频CEUS[(2.44±1.04)分、57.1%(36/63)],差异均有统计学意义(均P<0.05)。高频CEUS对最大径≤1 cm FLLs、最大径1~2 cm FLLs和肝转移瘤的检出率均显著高于低频CEUS[96.7%(29/30)vs.46.7%(14/30)、92.6%(25/27)vs.66.7%(18/27)、100%(26/26)vs.57.7%(15/26)],差异均有统计学意义(均P<0.001)。高频CEUS鉴别诊断浅表FLLs良恶性的灵敏度、准确率分别为92.9%、91.7%,均高于低频CEUS(78.6%、77.8%),差异均有统计学意义(均P<0.05)。结论高频CEUS在提高浅表FLLs的检出率和定性诊断方面均有明显优势,具有重要的临床价值。展开更多
Most of the melanoma cases of skin cancer are the life-threatening form of cancer.It is prevalent among the Caucasian group of people due to their light skin tone.Melanoma is the second most common cancer that hits th...Most of the melanoma cases of skin cancer are the life-threatening form of cancer.It is prevalent among the Caucasian group of people due to their light skin tone.Melanoma is the second most common cancer that hits the age group of 15–29 years.The high number of cases has increased the importance of automated systems for diagnosing.The diagnosis should be fast and accurate for the early treatment of melanoma.It should remove the need for biopsies and provide stable diagnostic results.Automation requires large quantities of images.Skin lesion datasets contain various kinds of dermoscopic images for the detection of melanoma.Three publicly available benchmark skin lesion datasets,ISIC 2017,ISBI 2016,and PH2,are used for the experiments.Currently,the ISIC archive and PH2 are the most challenging and demanding dermoscopic datasets.These datasets’pre-analysis is necessary to overcome contrast variations,under or over segmented images boundary extraction,and accurate skin lesion classification.In this paper,we proposed the statistical histogram-based method for the pre-categorization of skin lesion datasets.The image histogram properties are utilized to check the image contrast variations and categorized these images into high and low contrast images.The two performance measures,processing time and efficiency,are computed for evaluation of the proposed method.Our results showed that the proposed methodology improves the pre-processing efficiency of 77%of ISIC 2017,67%of ISBI 2016,and 92.5%of PH2 datasets.展开更多
基金National Natural Science Foundation of China,No.NSFC 81171389Key Program of Basic Research from Shanghai Municipal Science and Technology Commission,No.12JC1406500the Program of Shanghai Municipal Health Outstanding Discipline Leader,No.XBR 2013110
文摘AIM:To evaluate the feasibility of low contrast medium and radiation dose for hepatic computed tomography(CT) perfusion of rabbit VX2 tumor.METHODS:Eleven rabbits with hepatic VX2 tumor underwent perfusion CT scanning with a 24-h interval between a conventional tube potential(120 k Vp) protocol with 350 mg I/m L contrast medium and filtered back projection,and a low tube potential(80 k Vp) protocol with 270 mg I/m L contrast medium with iterative reconstruction.Correlation and agreement among perfusion parameters acquired by the conventional and low dose protocols were assessed for the viable tumor component as well as whole tumor.Image noise and tumor-to-liver contrast to noise ratio during arterial and portal venous phases were evaluated.RESULTS:A 38% reduction in contrast medium dose(360.1 ± 13.3 mg I/kg vs 583.5 ± 21.5 mg I/kg,P < 0.001) and a 73% decrease in radiation dose(1898.5 m Gy·cm vs 6951.8 m Gy·cm) were observed.Interestingly,there was a strong positive correlation in hepatic arterial perfusion(r = 0.907,P < 0.001;r = 0.879,P < 0.001),hepatic portal perfusion(r = 0.819,P = 0.002;r = 0.831,P = 0.002),and hepatic blood flow(r = 0.945,P < 0.001;r = 0.930,P < 0.001) as well as a moderate correlation in hepatic perfusion index(r = 0.736,P = 0.01;r = 0.636,P = 0.035) between the low dose protocol with iterative reconstruction and the conventional protocol for the viable tumor component and the whole tumor.These two imaging protocols provided a moderate but acceptable agreement for perfusion parameters and similar tumorto-liver CNR during arterial and portal venous phases(5.63 ± 2.38 vs 6.16 ± 2.60,P = 0.814;4.60 ± 1.27 vs 5.11 ± 1.74,P = 0.587).CONCLUSION:Compared with the conventional protocol,low contrast medium and radiation dose with iterative reconstruction has no significant influence on hepatic perfusion parameters for rabbits VX2 tumor.
文摘Objective To evaluate the feasibility of using a low concentration of contrast medium （Visipaque 270 mgl/mL）, low tube voltage, and an advanced image reconstruction algorithm in head and neck computed tomography angiography （CTA）. Methods Forty patients （22 men and 18 women; average age 48.7 ± 14.25 years; average body mass index 23.9 ± 3.7 kg/m^2） undergoing CTA for suspected vascular diseases were randomly assigned into two groups. Group A （n = 20） was administered 370 mgl/mL contrast medium, and group B （n = 20） was administered 270 mgl/mL contrast medium. Both groups were administered at a rate of 4.8 mL/s and an injection volume of 0.8 mL/kg. Images of group A were obtained with 120 kVp and filtered back projection （FBP） reconstruction, whereas images of group B were obtained with 80 kVp and 80% adaptive iterative statistical reconstruction algorithm （ASiR）. The CT values and standard deviations of intracranial arteries and image noise on the corona radiata were measured to calculate the contrast-to-noise ratio （CNR） and signal-to-noise ratio （SNR）. The beam-hardening artifacts （BHAs） around the skull base were calculated. Two readers evaluated the image quality with volume rendered images using scores from 1 to 5. The values between the two groups were statistically compared. Results The mean CT value of the intracranial arteries in group B was significantly higher than that in group A （P 〈 0.001）. The CNR and SNR values in group B were also statistically higher than those in group A （P 〈 0.001）. Image noise and BHAs were not significantly different between the two groups. The image quality score of VR images of in group B was significantly higher than that in group A （P = 0.001）. However, the quality scores of axial enhancement images in group B became significantly smaller than those in group A （P〈 0.001）. The CT dose index volume and dose-length product were decreased by 63.8% and 64%, respectively, in group B （P 〈 0.001 for both）. Conclusion Visipaque combined with 80 kVp and 80% ASiR provided similar image quality in intracranial CTA with 64% radiation dose reduction compared with the use of lopamidol, 120 kVp, and FBP reconstruc-tion.
文摘Text extraction is the key step in the character recognition;its accuracy highly relies on the location of the text region. In this paper, we propose a new method which can find the text location automatically to solve some regional problems such as incomplete, false position or orientation deviation occurred in the low-contrast image text extraction. Firstly, we make some pre-processing for the original image, including color space transform, contrast-limited adaptive histogram equalization, Sobel edge detector, morphological method and eight neighborhood processing method (ENPM) etc., to provide some results to compare the different methods. Secondly, we use the connected component analysis (CCA) method to get several connected parts and non-connected parts, then use the morphology method and CCA again for the non-connected part to erode some noises, obtain another connected and non-connected parts. Thirdly, we compute the edge feature for all connected areas, combine Support Vector Machine (SVM) to classify the real text region, obtain the text location coordinates. Finally, we use the text region coordinate to extract the block including the text, then binarize, cluster and recognize all text information. At last, we calculate the precision rate and recall rate to evaluate the method for more than 200 images. The experiments show that the method we proposed is robust for low-contrast text images with the variations in font size and font color, different language, gloomy environment, etc.
文摘Background: Chronic kidney disease patients are at a greater risk for nephropathy requiring dialysis after percutaneous coronary intervention. Such patients are usually deferred due to fear of “Renalism”.?Objectives This study assesses the outcome of Low dose contrast protocol during PCI in CKD patients whose e-GFR 60 ml/min/1.72 m and investigates a safety margin for contrast use in these high-risk categories.?Methods: Patients were into three groups according to CV/e-GFR ratio: Group (A) low-dose: CV/e-GFR ratio 2.0 Group (B) medium-dose: CV/e-GFR ratio > 2.0 and × bodyweight\s.creatinine). Group (C) high-dose: CV/e-GFR ratio > MACD. Results: A total of 73 patients were enrolled. Average age was 54 ± 8 years,81.4% were male and 18.6% were females and 52% were diabetic. Mean baseline e-GFR was 40 ± 8.0 ml/min/1.73m2. Contrast Volume used in group A was (58.26 ± 15.05) (n = 24), in group B (109.42 ± 17.11) (n = 26) and in group C (304.5 ± 60.30) (n = 23), respectively. The incidences of CI-AKI in the 3 groups were 0%, 11.5% and 35%, respectively (p = 0.02). All-cause death 0%, 17% and introduction of maintenance hemo dialysis was 0%, 11.5% and 26%, respectively (p Conclusion: Low dose contrast protocol is safe, effective and easily applicable technique without CI-AKI or death.
文摘目的探讨高频超声造影(CEUS)在浅表肝脏局灶性病变(FLLs)检出及诊断中的临床价值。方法选取我院浅表FLLs患者38例,共63个病变,分别使用低频凸阵探头和高频线阵探头对患者进行CEUS检查,比较低频CEUS与高频CEUS在病变可见度评分、检出率和良恶性鉴别诊断中的差异。结果浅表FLLs在高频CEUS下平均可见度评分和检出率分别为(3.62±0.79)分、93.7%(59/63),均显著高于低频CEUS[(2.44±1.04)分、57.1%(36/63)],差异均有统计学意义(均P<0.05)。高频CEUS对最大径≤1 cm FLLs、最大径1~2 cm FLLs和肝转移瘤的检出率均显著高于低频CEUS[96.7%(29/30)vs.46.7%(14/30)、92.6%(25/27)vs.66.7%(18/27)、100%(26/26)vs.57.7%(15/26)],差异均有统计学意义(均P<0.001)。高频CEUS鉴别诊断浅表FLLs良恶性的灵敏度、准确率分别为92.9%、91.7%,均高于低频CEUS(78.6%、77.8%),差异均有统计学意义(均P<0.05)。结论高频CEUS在提高浅表FLLs的检出率和定性诊断方面均有明显优势,具有重要的临床价值。
基金supported by the School of Computing,Faculty of Engineering,Universiti Teknologi Malaysia,Johor Bahru,81310 Skudai,Malaysia.
文摘Most of the melanoma cases of skin cancer are the life-threatening form of cancer.It is prevalent among the Caucasian group of people due to their light skin tone.Melanoma is the second most common cancer that hits the age group of 15–29 years.The high number of cases has increased the importance of automated systems for diagnosing.The diagnosis should be fast and accurate for the early treatment of melanoma.It should remove the need for biopsies and provide stable diagnostic results.Automation requires large quantities of images.Skin lesion datasets contain various kinds of dermoscopic images for the detection of melanoma.Three publicly available benchmark skin lesion datasets,ISIC 2017,ISBI 2016,and PH2,are used for the experiments.Currently,the ISIC archive and PH2 are the most challenging and demanding dermoscopic datasets.These datasets’pre-analysis is necessary to overcome contrast variations,under or over segmented images boundary extraction,and accurate skin lesion classification.In this paper,we proposed the statistical histogram-based method for the pre-categorization of skin lesion datasets.The image histogram properties are utilized to check the image contrast variations and categorized these images into high and low contrast images.The two performance measures,processing time and efficiency,are computed for evaluation of the proposed method.Our results showed that the proposed methodology improves the pre-processing efficiency of 77%of ISIC 2017,67%of ISBI 2016,and 92.5%of PH2 datasets.
