Objective This study aimed to explore the feasibility of enhancing image quality in computed tomography(CT) pulmonary angiography (CTPA) and reducing radiation dose using the nonlinear blending (NLB)technique of dual-...Objective This study aimed to explore the feasibility of enhancing image quality in computed tomography(CT) pulmonary angiography (CTPA) and reducing radiation dose using the nonlinear blending (NLB)technique of dual-energy CT.Methods A total of 61 patients scheduled for CTPA were enrolled, and 30 patients underwent dual-energyscanning. Nonlinear blending images (NLB group) and three groups of linear blending images (LB group,80 kV group, and 140 kV group) were reconstructed after scanning;31 patients underwent single-energyscanning (120 kV group). The CT values and standard deviations of the pulmonary trunk, left and rightpulmonary arteries, and ipsilateral back muscle at the bifurcation level of the left and right pulmonaryarteries were measured. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the fivegroups were calculated. The subjective image quality of the five groups was assessed. The radiation dosesof the dual- and single-energy groups were recorded and calculated.Results The CNR and SNR values of blood vessels in the NLB group were significantly higher than thosein the LB, 140 kV, and 80 kV groups (CNR of pulmonary artery trunk: t = 3.50, 4.06, 7.17, all P < 0.05;SNRof pulmonary trunk: t = 3.76, 4.71, 6.92, all P < 0.05). There were no statistical differences in the CNR andSNR values between the NLB group and 120 kV group (P > 0.05). The effective radiation dose of the dualenergygroup was lower than that of the single-energy group (t = –4.52, P < 0.05). The subjective scores ofimages in the NLB group were the highest (4.28 ± 0.74).Conclusion The NLB technique of dual-energy CT can improve the image quality of CTPA and reducethe radiation dose, providing more reliable imaging data for the clinical diagnosis of pulmonary embolism.展开更多
<strong>Objectives:</strong> To evaluate the diagnostic performance of the quantitative iodine parameters, including Iodine Concentration (IC), Normalized Iodine Concentration (NIC), and λ<sub>HU<...<strong>Objectives:</strong> To evaluate the diagnostic performance of the quantitative iodine parameters, including Iodine Concentration (IC), Normalized Iodine Concentration (NIC), and λ<sub>HU</sub>, in distinguishing malignant and benign thyroid nodules. <strong>Methods:</strong> Relevant studies were searched from Web of Science, PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure database and other complementary sources from inception to May 20, 2020. Study selection, data extraction, quality assessment, and data analyses were performed following the Cochrane standards and the PRISMA-DTA guideline. <strong>Results: </strong>Eight studies were included (595 patients with 737 thyroid nodules). The pooled sensitivity, specificity and summary diagnostic odds ratio of IC were 79% (95% CI: 69% - 86%), 76% (95% CI: 65% - 84%) and 11 (95% CI: 5 - 27) respectively;those of NIC were 78% (95% CI: 70% - 85%), 80% (95% CI: 74% - 85%) and 15 (95% CI: 9 - 24) respectively;those of λ<sub>HU</sub> were 80% (95% CI: 71% - 87%), 77% (95% CI: 70% - 83%) and 14 (95% CI: 8 - 24) respectively. <strong>Conclusion: </strong>DECT can be a potential evaluation tool for thyroid nodules. The NIC may be the most sensitive iodine parameter and could be comparable between different DECT machines in thyroid nodule assessment.展开更多
Objective:To explore the clinical value of dual energy CT(DECT)virtual noncalcium(VNCa)in the diagnosis of sacroiliac joint bone marrow edema(BME).Methods:A collection of 45 patients(21 males,24 females,and an average...Objective:To explore the clinical value of dual energy CT(DECT)virtual noncalcium(VNCa)in the diagnosis of sacroiliac joint bone marrow edema(BME).Methods:A collection of 45 patients(21 males,24 females,and an average age of 34 years)who underwent MRI and DECT(Siemens Somatom definition force)examinations for the sacroiliac joints in our hospital from January 2019 to August 2020.After the DECT scan,the bone marrow pseudo-color map was obtained after VNCa processing.The bone marrow pseudo-color map was evaluated by two physicians.Take MRI test results as the gold standard,the application value of DECT VNCa technology in the diagnosis of sacroiliac joint BME was analyzed.Results:The positive predictive value(PPV),negative predictive value(NPV),sensitivity(Sen),specificity(Spe)and accuracy(Acc)of the qualitative diagnosis of iliac bone and sacral BME with DECT VNCa technology was:80.6%,85.2%,78.4%,86.8%,83.3%and 100%,64.9%,32.5%,100%,70.0%,respectively.The area of edema displayed by quantitative measurement of DECT VNCa image is smaller than the area measured by MRI image.The VNCa CT value(-71.66±72.97Hu)of the iliac edema area was higher than that of the non-edema area(-90.27±65.85Hu),and the VNCa CT value of the sacral edema area(-62.90±46.87Hu)was higher than that of the non-edema area(-101.08±134.02Hu),the best cut-off values(Cut-off values)for the quantitative diagnosis of iliac bone and sacral BME by VNCa are-66.40Hu and-50.60Hu,respectively.The curve of the receiver operating characteristic(ROC)of the iliac bone and sacrum area under the cure(AUC)is 0.720 and 0.706 respectively.There is a moderate negative correlation between the VNCa CT values of the ilium and sacrum in the edema area and the conventional CT values.Conclusion:The DECT VNCa technique has certain effectiveness in the diagnosis of sacroiliac joint BME,and its effectiveness in the diagnosis of ilium BME is better than sacrum.展开更多
AIM:To correlate dual-energy computed tomography(DECT) pulmonary angiography derived iodine maps with parameter maps of quantitative pulmonary perfusion magnetic resonance imaging(MRI).METHODS:Eighteen patients with p...AIM:To correlate dual-energy computed tomography(DECT) pulmonary angiography derived iodine maps with parameter maps of quantitative pulmonary perfusion magnetic resonance imaging(MRI).METHODS:Eighteen patients with pulmonary perfusion defects detected on DECT derived iodine maps were included in this prospective study and additionally underwent time-resolved contrast-enhanced pulmonary MRI [dynamic contrast enhanced(DCE)-MRI].DCE-MRI data were quantitatively analyzed using a pixel-by-pixel deconvolution analysis calculating regional pulmonary blood flow(PBF),pulmonary blood volume(PBV) and mean transit time(MTT) in visually normal lung parenchyma and perfusion defects.Perfusion parameterswere correlated to mean attenuation values of normal lung and perfusion defects on DECT iodine maps.Two readers rated the concordance of perfusion defects in a visual analysis using a 5-point Likert-scale(1 = no correlation,5 = excellent correlation).RESULTS:In visually normal pulmonary tissue mean DECT and MRI values were:22.6 ± 8.3 Hounsfield units(HU);PBF:58.8 ± 36.0 mL/100 mL per minute;PBV:16.6 ± 8.5 mL;MTT:17.1 ± 10.3 s.In areas with restricted perfusion mean DECT and MRI values were:4.0 ± 3.9 HU;PBF:10.3 ± 5.5 mL/100 mL per minute,PBV:5 ± 4 mL,MTT:21.6 ± 14.0 s.The differences between visually normal parenchyma and areas of restricted perfusion were statistically significant for PBF,PBV and DECT(P < 0.0001).No linear correlation was found between MRI perfusion parameters and attenuation values of DECT iodine maps(PBF:r = 0.35,P = 0.15;PBV:r = 0.34,P = 0.16;MTT:r = 0.41,P = 0.08).Visual analysis revealed a moderate correlation between perfusion defects on DECT iodine maps and the parameter maps of DCE-MRI(mean score 3.6,k 0.45).CONCLUSION:There is a moderate visual but not statistically significant correlation between DECT iodine maps and perfusion parameter maps of DCE-MRI.展开更多
Objective To quantitatively compare and determine the best pancreatic tumor contrast to noise ratio (CNR) in different dual-energy derived datasets. Methods In this retrospective, single center study, 16 patients (9 m...Objective To quantitatively compare and determine the best pancreatic tumor contrast to noise ratio (CNR) in different dual-energy derived datasets. Methods In this retrospective, single center study, 16 patients (9 male, 7 female, average age 59.4±13.2 years) with pathologically diagnosed pancreatic cancer were enrolled. All patients received an abdominal scan using a dual source CT scanner 7 to 31 days before biopsy or surgery. After injection of iodine contrast agent, arterial and pancreatic parenchyma phase were scanned consequently, using a dual-energy scan mode (100 kVp/230 mAs and Sn 140 kVp/178 mAs) in the pancreatic parenchyma phase. A series of derived dual-energy datasets were evaluated including non-liner blending (non-linear blending width 0-500 HU; blending center -500 to 500 HU), mono-energetic (40-190 keV), 100 kVp and 140 kVp. On each datasets, mean CT values of the pancreatic parenchyma and tumor, as well as standard deviation CT values of subcutaneous fat and psoas muscle were measured. Regions of interest of cutaneous fat and major psoas muscle of 100 kVp and 140 kVp images were calculated. Best CNR of subcutaneous fat (CNR F ) and CNR of the major psoas muscle (CNR M ) of non-liner blending and mono-energetic datasets were calculated with the optimal mono-energetic keV setting and the optimal blending center/width setting for the best CNR. One Way ANOVA test was used for comparison of best CNR between different dual-energy derived datasets. Results The best CNR F (4.48±1.29) was obtained from the non-liner blending datasets at blending center -16.6±103.9 HU and blending width 12.3±10.6 HU. The best CNR F (3.28±0.97) was obtained from the mono-energetic datasets at 73.3±4.3 keV. CNR F in the 100 kVp and 140 kVp were 3.02±0.91 and 1.56±0.56 respectively. Using fat as the noise background, all of these images series showed significant differences (P<0.01) except best CNR F of mono-energetic image sets vs. CNR F of 100 kVp image (P=0.460). Similar results were found using muscle as the noise background (mono-energetic image vs. 100 kVp image: P=0.246; mono-energetic image vs. non-liner blending image: P=0.044; others: P<0.01). Conclusion Compared with mono-energetic datasets and low kVp datasets, non-linear blending image at automatically chosen blending width/window provides better tumor to the pancreas CNR, which might be beneficial for better detection of pancreatic tumors.展开更多
Objective To retrospectively determine the features of stones and calcifications in hepatobiliary system on virtual nonenhanced (VNE) dual-energy computed tomography (CT), and to evaluate the possibility of VNE images...Objective To retrospectively determine the features of stones and calcifications in hepatobiliary system on virtual nonenhanced (VNE) dual-energy computed tomography (CT), and to evaluate the possibility of VNE images in diagnosis for those lesions. Methods A total of 128 gall stones and calcifications of the liver found in 110 patients were examined with triple phase abdominal CT scan from July 2007 to December 2011, in which true nonenhanced (TNE) phase and arterial phase were performed with single-energy CT (120 kVp) and portal venous phase was performed with dual-energy CT (100 kVp and 140 kVp). VNE images were generated from the portal venous phase dual-energy CT data sets by using commercially VNC software. The mean CT values for the stone, liver, bile and paraspinal muscle, mean lesion density and size in area dimension, contrast-to-noise ratio (CNR) of lesion to the liver or bile, and image noise were assessed and compared between VNE and TNE images. The effective dose and size-specific dose estimate (SSDE) were also calculated. Results The mean CT values of the lesions measured on VNE images declined significantly compared with those measured on TNE images (164.51±102.13vs. 290.72±197.80 HU,P<0.001), so did the lesion-to-liver CNR (10.80±11.82vs.18.81±17.06,P<0.001) and the lesion-to-bile CNR (17.24±14.41 vs. 21.32±17.31,P<0.001). There was no significant difference in size of lesions area between VNE and TNE images (0.69±0.88vs.0.72±0.85 cm2,P=0.062). Compared to the 128 lesions found in TNE images, VNE images showed the same density in 30 (23.4%) lesions, lighter density in 88 (68.8%) lesions, while failed to show 10 (7.8%) lesions, and showed the same size in 61 (47.7%) lesions and smaller size in 57 (44.5%) lesions. The CT cutoff values of lesion and size were 229.21 HU and 0.15 cm2, respectively. The total effective dose for triple phase scan protocol with TNE images was 19.51±7.03 mSv, and the SSDE was 39.84±11.10 mGy. The effective dose for dual phase scan protocol with VNE images instead of TNE images was 13.29±4.89 mSv, and the SSDE was 27.83±9.99 mGy. Compared with TNE images, the effective dose and SSDE of VNE images were down by 32.05%±3.69 % and 30.63%±2.34 %, respectively. Conclusions Although the CT values and CNR of the lesions decreased in VNE images, the lesions of which attenuation greater than 229.21 HU and size larger than 0.15 cm2could be detected with good reliability and obvious dose reduction. There was good consistency in the size of stones and calcifications in hepatobiliary system between VNE images and TNE images, which ensured the possibility of the clinical application of VNE images.展开更多
The measurement of electron density is important for medical diagnosis and charged particle radiotherapy treatment planning.Traditionally,electron density is obtained by CT imaging using the relationship between CT-nu...The measurement of electron density is important for medical diagnosis and charged particle radiotherapy treatment planning.Traditionally,electron density is obtained by CT imaging using the relationship between CT-number and electron densities established beforehand.However,the measurement is not accurate due to the beam hardening effect.In this paper,we propose a simple and practical electron density acquisition method based on dual-energy CT technique.For each sample,the CT imaging is conducted using two selected X-ray energy from synchrotron radiation.A post-processing dual-energy reconstruction method is used.Linear attenuation coefficients of the scanned samples are obtained by FBP reconstruction.The effective atomic number and electron density are got by solving the dual-energy simultaneous equations.Different phantoms and breast tissues were scanned in this experimental study under 10 keV and 30 keV monochromatic X-rays.The distribution of effective atomic numbers and electron densities of the scanned phantoms were obtained by Dual-energy CT image reconstruction,which agrees well with the theoretical values.Compared with conventional methods,the measurement accuracy is greatly improved, and the measurement error is reduced to about 1%.This experimental study demonstrates that DECT imaging based on synchrotron radiation source is applicable to medical diagnosis for quantitative measurement with high accuracy.展开更多
Objective: To explore the significance of dual-energy CT non-linear fusion technique in improving the quality of CTA image of renal cancer. Methods: The CTA images of 100 patients who had been confirmed by pathology a...Objective: To explore the significance of dual-energy CT non-linear fusion technique in improving the quality of CTA image of renal cancer. Methods: The CTA images of 100 patients who had been confirmed by pathology as renal cancer were collected and were randomly divided into experimental group and control group with 50 cases respectively. The two groups of patients were treated with iodine concentration of 300 mg/ml and 350 mg/ml non-ionic contrast agent, with a dosage of 1.5 ml/kg and an injection rate of 4 ml/s. The contrast agent intelligently tracking method was adopted bolus. The control group used the conventional CTA scanning, with a reference tube voltage/tube current of 100 kv/ref150 mas. The experimental group adopted the double energy scanning, with ball tube A and ball tube B. The reference tube voltage/tube current was 100 kv/ref250 mas and sn150 kv/ref125 mas respectively. The images of the experimental group were non-linear fused to obtain the Mono+ 55 kev single-energy images. The CT value, SNR contrast ratio of the abdominal aorta, renal artery and tumor tissue of the experimental group images and the 100 KV images and the Mono+ 55 kev images of the control group were compared. The objective evaluation and subjective evaluation of the image quality of the three groups of images was performed. Results: The results showed that the 100 kV images of the experimental group were statistically different from those of the control group (P05) in CT value, SNR and CNR (P 0.05). And there was no statistically significant difference between the non-linear fusion single-energy Mono+ 55 kev images and the control group images in CT value, SNR and CNR (P > 0.05). The subjective evaluation of image quality showed that there was no significant difference between Mono+ 55 kev images and control group images, and the quality of Mono+ 55 kev images was higher than that of experimental group 100 kV images. Conclusion: The dual-energy CT non-linear fusion technique can improve the quality of CTA image in patients with renal cancer, and it is possible to obtain high quality CTA images with low iodine concentration contrast agent.展开更多
Purpose: To explore the significance of dual-source computed tomography (DECT) virtual monoenergetic reconstructions technology in improving the imaging quality of esophageal cancer patients. Materials and methods: 68...Purpose: To explore the significance of dual-source computed tomography (DECT) virtual monoenergetic reconstructions technology in improving the imaging quality of esophageal cancer patients. Materials and methods: 68 patients with clinically suspected esophageal cancer (all confirmed by pathology) were collected. Routine plain scan was performed with SIEMENS Force dual-energy CT and then dual-phase scans were performed. The venous phase images were respectively subjected to traditional virtual monoenergetic reconstructions (Mono_E) and new generation virtual monoenergetic reconstructions (Mono+). Mono_E 55 keV and Mono+ 55 keV virtual single-energy images were obtained respectively. The signal-to-noise ratio (SNR) of normal esophageal tissue and esophageal cancer lesions, noise and contrast noise ratio (CNR tumor) of normal esophageal tissue and esophageal cancer lesions were compared among 100 kV images, Mono_E images and Mono+ images. At the same time, two imaging physicians read the films and scored the images of each group by using a 5-point scoring method. Results: Mono+ 55 keV images, SNR, SNRtumor, noise and CNRtumor were statistically different from those of 100 kV images and Mono_E images (P < 0.05). And Mono+ 55 keV images also had the highest subjective score, with statistical significance (P 55 keV images had the best quality. Conclusion: The new generation of virtual monoenergetic reconstructions post-processing (Mono+) could reduce image noise and improve the contrast between esophageal cancer lesions and normal esophageal tissues, which was of great significance to improve the imaging quality of esophageal cancer patients and improve the early detection rate of esophageal cancer.展开更多
Purpose: To explore the significance of dual-source computed tomography (DECT) virtual monoenergetic reconstructions technology in improving image quality for portal vein system of pancreatic cancer patients. Material...Purpose: To explore the significance of dual-source computed tomography (DECT) virtual monoenergetic reconstructions technology in improving image quality for portal vein system of pancreatic cancer patients. Materials and methods: 47 patients with clinically suspected pancreatic cancer (all confirmed by pathology) were collected. Routine plain scan was performed with Siemens Force dual-source dual-energy CT followed by 3 scans respectively carried out in arterial phase, portal phase and delayed phase. Traditional virtual monoenergetic reconstructions (Mono_E) and new generation of virtual monoenergetic reconstructions (Mono+) were respectively performed on portal vein images to obtain virtual single energy images including Mono_ E70 keV, Mono_E 55 keV and Mono+ 70 keV and Mono+ 55 keV. The signal-to-noise ratio (SNR) and noise of portal vein, normal pancreatic tissues and pancreatic lesions of 100 kV, Mono_E and Mono+ images were compared. In addition, the contrast noise ratio of portal vein and lesions as well as pancreatic tissues and lesions (CNR PV, CNRtumor) were also compared. At the same time, two imaging physicians with rich clinical experiences read the films and scored the images of each group by using the 5-point scoring method. Results: Mono+ 55 keV images including SNRpv, SNRpanc, SNRtumor, Noise, CNRpv, CNRtumor were statistically different from 100 KV images and Mono_E images (P < 0.05). As for the subjective score, Mono+ 55 keV image score also had the highest score, which had statistical significance (P < 0.05). The results showed that Mono+ 55 keV images had the best quality. Conclusion: The new generation of virtual Mono+ post-treatment can reduce image noise. Low energy Mono+ images can improve the contrast between pancreatic cancer lesions and portal of pancreatic cancer patients.展开更多
Purpose: The K-edge of gold (81 keV) is located within the energy range of diagnostic CT. This might be advantageous for material differentiation in dual-energy CT (DECT). The aim of this in vitro study was to compare...Purpose: The K-edge of gold (81 keV) is located within the energy range of diagnostic CT. This might be advantageous for material differentiation in dual-energy CT (DECT). The aim of this in vitro study was to compare the differentiation between iodine or gold and body tissues using DECT at different kV spectra. Methods and Materials: A water filled tank phantom containing specimens with iodine (iopamidol), gold (sodium aurothiomalate), compact bone (compact porcine bone) and porcine muscle was scanned using a dual source CT (Definition, Siemens Healthcare). Consecutive scans were performed at 80 kVp, 100 kVp, 120 kVp and 140 kVp with constant mAs settings. The mean attenuation values of the specimens were measured, and differences in calculated dual-energy ratios (DEratio) between body tissues and iodine or gold were determined for different DE spectra. Results: The attenuation of gold increased compared to 80 kVp at higher kVp-settings, while the attenuation of all other specimens decreased. The calculated DEratios at 80/100 kVp, 80/120 kVp and 80/140 kVp were 1.31, 1.62 and 1.91 for iodine, 0.89, 0.88 and 0.92 for gold, 1.20, 1.39 and 1.45 for compact bone, 1.01, 1.03 and 1.08 for muscle. The differences between the DEratios 80/100 kVp, 80/120 kVp and 80/140 kVp were 0.11, 0.23 and 0.46 for iodine and bone, 0.31, 0.51 and 0.53 for gold and bone, 0.29, 0.59 and 0.83 for iodine and muscle, 0.12, 0.15 and 0.16 for gold and muscle. Conclusion: DEratio of gold remains relatively stable along the energy spectrum of diagnostic CT and allows a reliable material differentiation between gold and bone already at contiguous low tube voltage settings (80 kV and 100 kV). Thus, gold might have a potential as a contrast agent for DECT.展开更多
BACKGROUND Currently,the differentiation of jaw tumors is mainly based on the lesion’s morphology rather than the enhancement characteristics,which are important in the differentiation of neoplasms across the body.Th...BACKGROUND Currently,the differentiation of jaw tumors is mainly based on the lesion’s morphology rather than the enhancement characteristics,which are important in the differentiation of neoplasms across the body.There is a paucity of literature on the enhancement characteristics of jaw tumors.This is mainly because,even though computed tomography(CT)is used to evaluate these lesions,they are often imaged without intravenous contrast.This study hypothesised that the enhancement characteristics of the solid component of jaw tumors can aid in the differentiation of these lesions in addition to their morphology by dual-energy CT,therefore improving the ability to differentiate between various pathologies.AIM To evaluate the role of contrast enhancement and dual-energy quantitative parameters in CT in the differentiation of jaw tumors.METHODS Fifty-seven patients with jaw tumors underwent contrast-enhanced dual-energy CT.Morphological analysis of the tumor,including the enhancing solid component,was done,followed by quantitative analysis of iodine concentration(IC),water concentration(WC),HU,and normalized IC.The study population was divided into four subgroups based on histopathological analysis-central giant cell granuloma(CGCG),ameloblastoma,odontogenic keratocyst(OKC),and other jaw tumors.A one-way ANOVA test for parametric variables and the Kruskal-Wallis test for nonparametric variables were used.If significant differences were found,a series of independent t-tests or Mann-Whitney U tests were used.RESULTS Ameloblastoma was the most common pathology(n=20),followed by CGCG(n=11)and OKC.CGCG showed a higher mean concentration of all quantitative parameters than ameloblastomas(P<0.05).An IC threshold of 31.35×100μg/cm^(3) had the maximum sensitivity(81.8%)and specificity(65%).Between ameloblastomas and OKC,the former showed a higher mean concentration of all quantitative parameters(P<0.001),however when comparing unilocular ameloblastomas with OKCs,the latter showed significantly higher WC.Also,ameloblastoma had a higher IC and lower WC compared to“other jaw tumors”group.CONCLUSION Enhancement characteristics of solid components combined with dual-energy parameters offer a more precise way to differentiate between jaw tumors.展开更多
基金Supported by a grant from the Science and Technology Plan of Sichuan Province(No.2021YFS0225)the Science and Technology Plan of Chengdu(No.2021-YF05-01507-SN).
文摘Objective This study aimed to explore the feasibility of enhancing image quality in computed tomography(CT) pulmonary angiography (CTPA) and reducing radiation dose using the nonlinear blending (NLB)technique of dual-energy CT.Methods A total of 61 patients scheduled for CTPA were enrolled, and 30 patients underwent dual-energyscanning. Nonlinear blending images (NLB group) and three groups of linear blending images (LB group,80 kV group, and 140 kV group) were reconstructed after scanning;31 patients underwent single-energyscanning (120 kV group). The CT values and standard deviations of the pulmonary trunk, left and rightpulmonary arteries, and ipsilateral back muscle at the bifurcation level of the left and right pulmonaryarteries were measured. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the fivegroups were calculated. The subjective image quality of the five groups was assessed. The radiation dosesof the dual- and single-energy groups were recorded and calculated.Results The CNR and SNR values of blood vessels in the NLB group were significantly higher than thosein the LB, 140 kV, and 80 kV groups (CNR of pulmonary artery trunk: t = 3.50, 4.06, 7.17, all P < 0.05;SNRof pulmonary trunk: t = 3.76, 4.71, 6.92, all P < 0.05). There were no statistical differences in the CNR andSNR values between the NLB group and 120 kV group (P > 0.05). The effective radiation dose of the dualenergygroup was lower than that of the single-energy group (t = –4.52, P < 0.05). The subjective scores ofimages in the NLB group were the highest (4.28 ± 0.74).Conclusion The NLB technique of dual-energy CT can improve the image quality of CTPA and reducethe radiation dose, providing more reliable imaging data for the clinical diagnosis of pulmonary embolism.
文摘<strong>Objectives:</strong> To evaluate the diagnostic performance of the quantitative iodine parameters, including Iodine Concentration (IC), Normalized Iodine Concentration (NIC), and λ<sub>HU</sub>, in distinguishing malignant and benign thyroid nodules. <strong>Methods:</strong> Relevant studies were searched from Web of Science, PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure database and other complementary sources from inception to May 20, 2020. Study selection, data extraction, quality assessment, and data analyses were performed following the Cochrane standards and the PRISMA-DTA guideline. <strong>Results: </strong>Eight studies were included (595 patients with 737 thyroid nodules). The pooled sensitivity, specificity and summary diagnostic odds ratio of IC were 79% (95% CI: 69% - 86%), 76% (95% CI: 65% - 84%) and 11 (95% CI: 5 - 27) respectively;those of NIC were 78% (95% CI: 70% - 85%), 80% (95% CI: 74% - 85%) and 15 (95% CI: 9 - 24) respectively;those of λ<sub>HU</sub> were 80% (95% CI: 71% - 87%), 77% (95% CI: 70% - 83%) and 14 (95% CI: 8 - 24) respectively. <strong>Conclusion: </strong>DECT can be a potential evaluation tool for thyroid nodules. The NIC may be the most sensitive iodine parameter and could be comparable between different DECT machines in thyroid nodule assessment.
基金Project:Outstanding Youth Startup Foundation of Shanxi Province(No.2019YJ08)。
文摘Objective:To explore the clinical value of dual energy CT(DECT)virtual noncalcium(VNCa)in the diagnosis of sacroiliac joint bone marrow edema(BME).Methods:A collection of 45 patients(21 males,24 females,and an average age of 34 years)who underwent MRI and DECT(Siemens Somatom definition force)examinations for the sacroiliac joints in our hospital from January 2019 to August 2020.After the DECT scan,the bone marrow pseudo-color map was obtained after VNCa processing.The bone marrow pseudo-color map was evaluated by two physicians.Take MRI test results as the gold standard,the application value of DECT VNCa technology in the diagnosis of sacroiliac joint BME was analyzed.Results:The positive predictive value(PPV),negative predictive value(NPV),sensitivity(Sen),specificity(Spe)and accuracy(Acc)of the qualitative diagnosis of iliac bone and sacral BME with DECT VNCa technology was:80.6%,85.2%,78.4%,86.8%,83.3%and 100%,64.9%,32.5%,100%,70.0%,respectively.The area of edema displayed by quantitative measurement of DECT VNCa image is smaller than the area measured by MRI image.The VNCa CT value(-71.66±72.97Hu)of the iliac edema area was higher than that of the non-edema area(-90.27±65.85Hu),and the VNCa CT value of the sacral edema area(-62.90±46.87Hu)was higher than that of the non-edema area(-101.08±134.02Hu),the best cut-off values(Cut-off values)for the quantitative diagnosis of iliac bone and sacral BME by VNCa are-66.40Hu and-50.60Hu,respectively.The curve of the receiver operating characteristic(ROC)of the iliac bone and sacrum area under the cure(AUC)is 0.720 and 0.706 respectively.There is a moderate negative correlation between the VNCa CT values of the ilium and sacrum in the edema area and the conventional CT values.Conclusion:The DECT VNCa technique has certain effectiveness in the diagnosis of sacroiliac joint BME,and its effectiveness in the diagnosis of ilium BME is better than sacrum.
文摘AIM:To correlate dual-energy computed tomography(DECT) pulmonary angiography derived iodine maps with parameter maps of quantitative pulmonary perfusion magnetic resonance imaging(MRI).METHODS:Eighteen patients with pulmonary perfusion defects detected on DECT derived iodine maps were included in this prospective study and additionally underwent time-resolved contrast-enhanced pulmonary MRI [dynamic contrast enhanced(DCE)-MRI].DCE-MRI data were quantitatively analyzed using a pixel-by-pixel deconvolution analysis calculating regional pulmonary blood flow(PBF),pulmonary blood volume(PBV) and mean transit time(MTT) in visually normal lung parenchyma and perfusion defects.Perfusion parameterswere correlated to mean attenuation values of normal lung and perfusion defects on DECT iodine maps.Two readers rated the concordance of perfusion defects in a visual analysis using a 5-point Likert-scale(1 = no correlation,5 = excellent correlation).RESULTS:In visually normal pulmonary tissue mean DECT and MRI values were:22.6 ± 8.3 Hounsfield units(HU);PBF:58.8 ± 36.0 mL/100 mL per minute;PBV:16.6 ± 8.5 mL;MTT:17.1 ± 10.3 s.In areas with restricted perfusion mean DECT and MRI values were:4.0 ± 3.9 HU;PBF:10.3 ± 5.5 mL/100 mL per minute,PBV:5 ± 4 mL,MTT:21.6 ± 14.0 s.The differences between visually normal parenchyma and areas of restricted perfusion were statistically significant for PBF,PBV and DECT(P < 0.0001).No linear correlation was found between MRI perfusion parameters and attenuation values of DECT iodine maps(PBF:r = 0.35,P = 0.15;PBV:r = 0.34,P = 0.16;MTT:r = 0.41,P = 0.08).Visual analysis revealed a moderate correlation between perfusion defects on DECT iodine maps and the parameter maps of DCE-MRI(mean score 3.6,k 0.45).CONCLUSION:There is a moderate visual but not statistically significant correlation between DECT iodine maps and perfusion parameter maps of DCE-MRI.
文摘Objective To quantitatively compare and determine the best pancreatic tumor contrast to noise ratio (CNR) in different dual-energy derived datasets. Methods In this retrospective, single center study, 16 patients (9 male, 7 female, average age 59.4±13.2 years) with pathologically diagnosed pancreatic cancer were enrolled. All patients received an abdominal scan using a dual source CT scanner 7 to 31 days before biopsy or surgery. After injection of iodine contrast agent, arterial and pancreatic parenchyma phase were scanned consequently, using a dual-energy scan mode (100 kVp/230 mAs and Sn 140 kVp/178 mAs) in the pancreatic parenchyma phase. A series of derived dual-energy datasets were evaluated including non-liner blending (non-linear blending width 0-500 HU; blending center -500 to 500 HU), mono-energetic (40-190 keV), 100 kVp and 140 kVp. On each datasets, mean CT values of the pancreatic parenchyma and tumor, as well as standard deviation CT values of subcutaneous fat and psoas muscle were measured. Regions of interest of cutaneous fat and major psoas muscle of 100 kVp and 140 kVp images were calculated. Best CNR of subcutaneous fat (CNR F ) and CNR of the major psoas muscle (CNR M ) of non-liner blending and mono-energetic datasets were calculated with the optimal mono-energetic keV setting and the optimal blending center/width setting for the best CNR. One Way ANOVA test was used for comparison of best CNR between different dual-energy derived datasets. Results The best CNR F (4.48±1.29) was obtained from the non-liner blending datasets at blending center -16.6±103.9 HU and blending width 12.3±10.6 HU. The best CNR F (3.28±0.97) was obtained from the mono-energetic datasets at 73.3±4.3 keV. CNR F in the 100 kVp and 140 kVp were 3.02±0.91 and 1.56±0.56 respectively. Using fat as the noise background, all of these images series showed significant differences (P<0.01) except best CNR F of mono-energetic image sets vs. CNR F of 100 kVp image (P=0.460). Similar results were found using muscle as the noise background (mono-energetic image vs. 100 kVp image: P=0.246; mono-energetic image vs. non-liner blending image: P=0.044; others: P<0.01). Conclusion Compared with mono-energetic datasets and low kVp datasets, non-linear blending image at automatically chosen blending width/window provides better tumor to the pancreas CNR, which might be beneficial for better detection of pancreatic tumors.
基金Supported by the Health Industry Special Scientific Research Project(201402019)
文摘Objective To retrospectively determine the features of stones and calcifications in hepatobiliary system on virtual nonenhanced (VNE) dual-energy computed tomography (CT), and to evaluate the possibility of VNE images in diagnosis for those lesions. Methods A total of 128 gall stones and calcifications of the liver found in 110 patients were examined with triple phase abdominal CT scan from July 2007 to December 2011, in which true nonenhanced (TNE) phase and arterial phase were performed with single-energy CT (120 kVp) and portal venous phase was performed with dual-energy CT (100 kVp and 140 kVp). VNE images were generated from the portal venous phase dual-energy CT data sets by using commercially VNC software. The mean CT values for the stone, liver, bile and paraspinal muscle, mean lesion density and size in area dimension, contrast-to-noise ratio (CNR) of lesion to the liver or bile, and image noise were assessed and compared between VNE and TNE images. The effective dose and size-specific dose estimate (SSDE) were also calculated. Results The mean CT values of the lesions measured on VNE images declined significantly compared with those measured on TNE images (164.51±102.13vs. 290.72±197.80 HU,P<0.001), so did the lesion-to-liver CNR (10.80±11.82vs.18.81±17.06,P<0.001) and the lesion-to-bile CNR (17.24±14.41 vs. 21.32±17.31,P<0.001). There was no significant difference in size of lesions area between VNE and TNE images (0.69±0.88vs.0.72±0.85 cm2,P=0.062). Compared to the 128 lesions found in TNE images, VNE images showed the same density in 30 (23.4%) lesions, lighter density in 88 (68.8%) lesions, while failed to show 10 (7.8%) lesions, and showed the same size in 61 (47.7%) lesions and smaller size in 57 (44.5%) lesions. The CT cutoff values of lesion and size were 229.21 HU and 0.15 cm2, respectively. The total effective dose for triple phase scan protocol with TNE images was 19.51±7.03 mSv, and the SSDE was 39.84±11.10 mGy. The effective dose for dual phase scan protocol with VNE images instead of TNE images was 13.29±4.89 mSv, and the SSDE was 27.83±9.99 mGy. Compared with TNE images, the effective dose and SSDE of VNE images were down by 32.05%±3.69 % and 30.63%±2.34 %, respectively. Conclusions Although the CT values and CNR of the lesions decreased in VNE images, the lesions of which attenuation greater than 229.21 HU and size larger than 0.15 cm2could be detected with good reliability and obvious dose reduction. There was good consistency in the size of stones and calcifications in hepatobiliary system between VNE images and TNE images, which ensured the possibility of the clinical application of VNE images.
基金supported by National Key Technology R&D Program of the Ministry of Science and Technology(No.2012BA107B05)
文摘The measurement of electron density is important for medical diagnosis and charged particle radiotherapy treatment planning.Traditionally,electron density is obtained by CT imaging using the relationship between CT-number and electron densities established beforehand.However,the measurement is not accurate due to the beam hardening effect.In this paper,we propose a simple and practical electron density acquisition method based on dual-energy CT technique.For each sample,the CT imaging is conducted using two selected X-ray energy from synchrotron radiation.A post-processing dual-energy reconstruction method is used.Linear attenuation coefficients of the scanned samples are obtained by FBP reconstruction.The effective atomic number and electron density are got by solving the dual-energy simultaneous equations.Different phantoms and breast tissues were scanned in this experimental study under 10 keV and 30 keV monochromatic X-rays.The distribution of effective atomic numbers and electron densities of the scanned phantoms were obtained by Dual-energy CT image reconstruction,which agrees well with the theoretical values.Compared with conventional methods,the measurement accuracy is greatly improved, and the measurement error is reduced to about 1%.This experimental study demonstrates that DECT imaging based on synchrotron radiation source is applicable to medical diagnosis for quantitative measurement with high accuracy.
文摘Objective: To explore the significance of dual-energy CT non-linear fusion technique in improving the quality of CTA image of renal cancer. Methods: The CTA images of 100 patients who had been confirmed by pathology as renal cancer were collected and were randomly divided into experimental group and control group with 50 cases respectively. The two groups of patients were treated with iodine concentration of 300 mg/ml and 350 mg/ml non-ionic contrast agent, with a dosage of 1.5 ml/kg and an injection rate of 4 ml/s. The contrast agent intelligently tracking method was adopted bolus. The control group used the conventional CTA scanning, with a reference tube voltage/tube current of 100 kv/ref150 mas. The experimental group adopted the double energy scanning, with ball tube A and ball tube B. The reference tube voltage/tube current was 100 kv/ref250 mas and sn150 kv/ref125 mas respectively. The images of the experimental group were non-linear fused to obtain the Mono+ 55 kev single-energy images. The CT value, SNR contrast ratio of the abdominal aorta, renal artery and tumor tissue of the experimental group images and the 100 KV images and the Mono+ 55 kev images of the control group were compared. The objective evaluation and subjective evaluation of the image quality of the three groups of images was performed. Results: The results showed that the 100 kV images of the experimental group were statistically different from those of the control group (P05) in CT value, SNR and CNR (P 0.05). And there was no statistically significant difference between the non-linear fusion single-energy Mono+ 55 kev images and the control group images in CT value, SNR and CNR (P > 0.05). The subjective evaluation of image quality showed that there was no significant difference between Mono+ 55 kev images and control group images, and the quality of Mono+ 55 kev images was higher than that of experimental group 100 kV images. Conclusion: The dual-energy CT non-linear fusion technique can improve the quality of CTA image in patients with renal cancer, and it is possible to obtain high quality CTA images with low iodine concentration contrast agent.
文摘Purpose: To explore the significance of dual-source computed tomography (DECT) virtual monoenergetic reconstructions technology in improving the imaging quality of esophageal cancer patients. Materials and methods: 68 patients with clinically suspected esophageal cancer (all confirmed by pathology) were collected. Routine plain scan was performed with SIEMENS Force dual-energy CT and then dual-phase scans were performed. The venous phase images were respectively subjected to traditional virtual monoenergetic reconstructions (Mono_E) and new generation virtual monoenergetic reconstructions (Mono+). Mono_E 55 keV and Mono+ 55 keV virtual single-energy images were obtained respectively. The signal-to-noise ratio (SNR) of normal esophageal tissue and esophageal cancer lesions, noise and contrast noise ratio (CNR tumor) of normal esophageal tissue and esophageal cancer lesions were compared among 100 kV images, Mono_E images and Mono+ images. At the same time, two imaging physicians read the films and scored the images of each group by using a 5-point scoring method. Results: Mono+ 55 keV images, SNR, SNRtumor, noise and CNRtumor were statistically different from those of 100 kV images and Mono_E images (P < 0.05). And Mono+ 55 keV images also had the highest subjective score, with statistical significance (P 55 keV images had the best quality. Conclusion: The new generation of virtual monoenergetic reconstructions post-processing (Mono+) could reduce image noise and improve the contrast between esophageal cancer lesions and normal esophageal tissues, which was of great significance to improve the imaging quality of esophageal cancer patients and improve the early detection rate of esophageal cancer.
文摘Purpose: To explore the significance of dual-source computed tomography (DECT) virtual monoenergetic reconstructions technology in improving image quality for portal vein system of pancreatic cancer patients. Materials and methods: 47 patients with clinically suspected pancreatic cancer (all confirmed by pathology) were collected. Routine plain scan was performed with Siemens Force dual-source dual-energy CT followed by 3 scans respectively carried out in arterial phase, portal phase and delayed phase. Traditional virtual monoenergetic reconstructions (Mono_E) and new generation of virtual monoenergetic reconstructions (Mono+) were respectively performed on portal vein images to obtain virtual single energy images including Mono_ E70 keV, Mono_E 55 keV and Mono+ 70 keV and Mono+ 55 keV. The signal-to-noise ratio (SNR) and noise of portal vein, normal pancreatic tissues and pancreatic lesions of 100 kV, Mono_E and Mono+ images were compared. In addition, the contrast noise ratio of portal vein and lesions as well as pancreatic tissues and lesions (CNR PV, CNRtumor) were also compared. At the same time, two imaging physicians with rich clinical experiences read the films and scored the images of each group by using the 5-point scoring method. Results: Mono+ 55 keV images including SNRpv, SNRpanc, SNRtumor, Noise, CNRpv, CNRtumor were statistically different from 100 KV images and Mono_E images (P < 0.05). As for the subjective score, Mono+ 55 keV image score also had the highest score, which had statistical significance (P < 0.05). The results showed that Mono+ 55 keV images had the best quality. Conclusion: The new generation of virtual Mono+ post-treatment can reduce image noise. Low energy Mono+ images can improve the contrast between pancreatic cancer lesions and portal of pancreatic cancer patients.
文摘Purpose: The K-edge of gold (81 keV) is located within the energy range of diagnostic CT. This might be advantageous for material differentiation in dual-energy CT (DECT). The aim of this in vitro study was to compare the differentiation between iodine or gold and body tissues using DECT at different kV spectra. Methods and Materials: A water filled tank phantom containing specimens with iodine (iopamidol), gold (sodium aurothiomalate), compact bone (compact porcine bone) and porcine muscle was scanned using a dual source CT (Definition, Siemens Healthcare). Consecutive scans were performed at 80 kVp, 100 kVp, 120 kVp and 140 kVp with constant mAs settings. The mean attenuation values of the specimens were measured, and differences in calculated dual-energy ratios (DEratio) between body tissues and iodine or gold were determined for different DE spectra. Results: The attenuation of gold increased compared to 80 kVp at higher kVp-settings, while the attenuation of all other specimens decreased. The calculated DEratios at 80/100 kVp, 80/120 kVp and 80/140 kVp were 1.31, 1.62 and 1.91 for iodine, 0.89, 0.88 and 0.92 for gold, 1.20, 1.39 and 1.45 for compact bone, 1.01, 1.03 and 1.08 for muscle. The differences between the DEratios 80/100 kVp, 80/120 kVp and 80/140 kVp were 0.11, 0.23 and 0.46 for iodine and bone, 0.31, 0.51 and 0.53 for gold and bone, 0.29, 0.59 and 0.83 for iodine and muscle, 0.12, 0.15 and 0.16 for gold and muscle. Conclusion: DEratio of gold remains relatively stable along the energy spectrum of diagnostic CT and allows a reliable material differentiation between gold and bone already at contiguous low tube voltage settings (80 kV and 100 kV). Thus, gold might have a potential as a contrast agent for DECT.
文摘BACKGROUND Currently,the differentiation of jaw tumors is mainly based on the lesion’s morphology rather than the enhancement characteristics,which are important in the differentiation of neoplasms across the body.There is a paucity of literature on the enhancement characteristics of jaw tumors.This is mainly because,even though computed tomography(CT)is used to evaluate these lesions,they are often imaged without intravenous contrast.This study hypothesised that the enhancement characteristics of the solid component of jaw tumors can aid in the differentiation of these lesions in addition to their morphology by dual-energy CT,therefore improving the ability to differentiate between various pathologies.AIM To evaluate the role of contrast enhancement and dual-energy quantitative parameters in CT in the differentiation of jaw tumors.METHODS Fifty-seven patients with jaw tumors underwent contrast-enhanced dual-energy CT.Morphological analysis of the tumor,including the enhancing solid component,was done,followed by quantitative analysis of iodine concentration(IC),water concentration(WC),HU,and normalized IC.The study population was divided into four subgroups based on histopathological analysis-central giant cell granuloma(CGCG),ameloblastoma,odontogenic keratocyst(OKC),and other jaw tumors.A one-way ANOVA test for parametric variables and the Kruskal-Wallis test for nonparametric variables were used.If significant differences were found,a series of independent t-tests or Mann-Whitney U tests were used.RESULTS Ameloblastoma was the most common pathology(n=20),followed by CGCG(n=11)and OKC.CGCG showed a higher mean concentration of all quantitative parameters than ameloblastomas(P<0.05).An IC threshold of 31.35×100μg/cm^(3) had the maximum sensitivity(81.8%)and specificity(65%).Between ameloblastomas and OKC,the former showed a higher mean concentration of all quantitative parameters(P<0.001),however when comparing unilocular ameloblastomas with OKCs,the latter showed significantly higher WC.Also,ameloblastoma had a higher IC and lower WC compared to“other jaw tumors”group.CONCLUSION Enhancement characteristics of solid components combined with dual-energy parameters offer a more precise way to differentiate between jaw tumors.
