Sim Grid and S-Enhance post processing algorithm for improving image quality of low-dose X-ray films in children / 中国介入影像与治疗学

Objective To observe the value of SimGrid(SG)and S-Enhance(SE)for improving image quality of low-dose X-ray films in children.Methods Data of 344 children in intensive care unit who underwent 410 times bedside X-ray examinations,including 290 times of chest X-ray,51 of abdominal X-ray and 69 of chest and abdominal combined X-ray were enrolled.SG and SE were respectively used for post-processing,and the quality of post-processed images were analyzed.Results Among 410 SG post-processing images,250 images were classified as 2-point,147 as 1-point and 13 as 0-point.SG could significantly improve image quality of children≥1 year and body mass≥10 kg(all P＜0.05),with better ability for displaying bones,trachea,peripheral blood vessels,foreign objects,psoas major muscle and intestinal gas(all P＜0.05).Among 410 SE post-processing images,250 images were classified as 2-point,58 as 1-point and 102 of 0-point.SE could significantly improve image quality of children≥0.5 years and with body mass＞4 kg(all P＜0.05),with better ability for displaying bones,trachea,large blood vessels,peripheral vessels,heart posterior blood vessels and foreign objects(all P＜0.05).Conclusion SG could significantly improve displaying of bones,trachea,peripheral blood vessels,foreign objects,psoas major muscle and intestinal gas in children≥1 year and body mass≥10 kg,while SE could improve displaying of bones,trachea,large blood vessels,peripheral blood vessels,heart posterior blood vessels and foreign objects in children aged≥0.5 years and body mass＞4 kg on low-dose X-ray films.

Application of 3D MERGE sequence versus 3D SPACE STIR sequence in the examination of lumbar disc herniation / 中国医学物理学杂志

Objective To compare the performances of 3D MERGE sequence and 3D SPACE STIR sequence in detecting lumbar disc herniation(LDH).Methods The clinical data and MRI data of 135 LDH patients admitted between January 2020 and November 2022 were analyzed retrospectively.All patients were examined using conventional MRI,3D MERGE sequence and 3D SPACE STIR sequence.The consistency of 3D MERGE sequence and 3D SPACE STIR sequence in measuring the diameter of nerve root was analyzed,and the image quality parameters[signal-to-noise ratio(SNR),contrast-to-noise ratio(CNR)]and image definition score of the two sequences were evaluated.Results There were no statistically significant differences in L3-S1 nerve root diameters measured by 3D MERGE sequence and 3D SPACE STIR sequence(P＞0.05),and the diameters of L3,L4,L5 and S1 measured by the two sequences showed high correlations(r=0.957,0.986,0.975,0.972,P＜0.05).Compared with 3D SPACE STIR sequence,3D MERGE sequence had higher SNR and CNR,scored better on image definition,and displayed nerve root more clearly(P＜0.05).Conclusion 3D MERGE sequence and 3D SPACE STIR sequence have high consistency in the measurement of LDH nerve root diameter.3D MERGE sequence can display the anatomical morphology of nerve root more clearly as compared with 3D SPACE STIR sequence,and the former one has higher image quality.

Diagnostic value of MRI using proton density-weighted fat-saturated sequence for bone marrow edema in osteoarticular injury / 中国医学物理学杂志

Objective To analyze the value of magnetic resonance proton density-weighted fat-saturated(PDWI-FS)sequence in the diagnosis of bone marrow edema(BME)in osteoarticular injury.Methods A total of 150 patients with bone and joint trauma were enrolled in the study.All patients underwent sagittal PDWI-FS sequence scan and conventional MRI sequence scan.The BME detection,signal intensity,image quality,and the signal-to-noise ratio and contrast-to-noise ratio of the lesions were compared between two methods.Results Both methods revealed that there were 225 sites of BME signs in 134 out of the 150 patients,with a higher prevalence in knee joint trauma patients.The signal intensity of the lesions was mainly grade 3 on PDWI-FS sequence and grade 2 on conventional MRI sequence,accounting for 97.78%(220/225)and 43.11%(97/225),indicating that the two methods graded signal intensity differently(Z=15.919,P<0.05).PDWI-FS sequence and conventional sequence had scores of 4.09±0.45 vs 3.88±0.39,3.65±0.42 vs 3.41±0.36,3.25±0.37 vs 3.14±0.35 and 4.21±0.38 vs 3.97±0.34 on lesion clarity,spatial resolution,anamorphosis and diagnostic confidence,and the former scored higher(t=4.319,5.314,2.645,5.765;P<0.05).The signal-to-noise ratio and contrast-to-noise ratio of the lesions on PDWI-FS sequence were 2.07±0.23 and 5.52±0.64,higher than 2.01±0.22 and 5.17±0.59 on conventional sequence,and the differences were statistically significant(t=2.309,4.925;P<0.05).Conclusion Compared with conventional MRI sequence,magnetic resonance PDWI-FS sequence can effectively enhance image quality and display lesions more clearly,providing more accurate information for the diagnosis of BME in osteoarticular injury.

Correlations between image quality and radiation dose in prospective and retrospective ECG-gated CT coronary angiography in patients with different heart rates / 中国医学物理学杂志

Objective To explore the correlations between image quality of prospective and retrospective electrocardiogram(ECG)-gated CT coronary angiogram and radiation dose in patients with different heart rates.Methods A total of 135 patients undergoing 256-slice spiral CT coronary angiography were enrolled in the study.Among them,66 cases received prospective ECG-gated scanning(prospective ECG-gated group)and further divided into two subgroups with heart rate≤80 beats/min(prospective ECG-gated+low heart rate subgroup,n=39)and>80 beats/min(prospective ECG-gated+high heart rate subgroup,n=27).The other 69 cases underwent retrospective ECG-gated scanning(retrospective ECG-gated group),including 45 cases with heart rate≤80 beats/min(retrospective ECG-gated+low heart rate subgroup)and 24 with heart rate>80 beats/min(retrospective ECG-gated+high heart rate subgroup).The baseline data,image quality[mean CT value,image noise,signal-to-noise ratio(SNR),subjective image quality score]and radiation dos[CT volume dose index(CTDIvol),dose length product(DLP),effective dose(ED)]were compared among 4 subgroups.The correlations of image quality with heart rate and radiation dose in prospective and retrospective ECG-gated groups were analyzed.Results The heart rates in prospective and retrospective ECG-gated+low heart rate subgroups were lower than those in prospective and retrospective ECG-gated+high heart rate subgroups(P<0.05).When comparing the mean CT value,image noise,SNR and subjective image quality score among 4 subgroups,no statistically significant differences were observed(P>0.05).The CTDIvol,DLP and ED in prospective ECG-gated+low heart rate subgroup were significantly lower than those in the other 3 subgroups(P<0.05),and the indicators in prospective ECG-gated+high heart rate subgroup were lower than those in retrospective ECG-gated group(including low and high heart rate subgroups)(P<0.05).Pearson correlation coefficient analysis revealed that the mean CT value,image noise,SNR,subjective image quality score had no significant correlation with heart rate,CTDIvol,DLP and ED in prospective and retrospective ECG-gated groups(P>0.05).Conclusion The subjective and objective image quality of 256-slice spiral CT coronary angiography is not correlated with radiation dose.Prospective ECG-gated scanning can reduce the radiation dose and ensure the image quality as compared with retrospective ECG-gated scanning.This holds true for eligible patients with high heart rate,and the former can effectively reduce radiation exposure.Therefore,prospective ECG-gated scanning is worthy to be promoted in clinic.

Effect of Shortening PET/CT Acquisition Time on the Diagnosis of Parkinson's Disease / 中国医学影像学杂志

Purpose To investigate the effect of shortening the acquisition time of 18F-D6-AV133 PET/CT on image quality and diagnostic efficacy in Parkinson's disease.Materials and Methods A total of 51 participants(27 of Parkinson's disease,24 of healthy-controls)from the First Affiliated Hospital of Guangzhou Medical University from October 2021 to June 2022 were retrospectively selected.Images were obtained after the injection of the tracer 18F-D6-AV133(371.04±16.30)MBq for 60 min,with collection times of 10 min.Four sets of images were reconstructed using CT attenuation correction with acquisition times of 3,5,7 and 10 min.Semi-quantitative analysis was performed on the PET images,calculating the striatum-to-occipital lobe standardized uptake value ratio(SUVR).Two physicians independently conducted qualitative evaluations for each image group.The differences of SUVR and visual score results among four sets of images were performed.The optimal critical value of SUVR was obtained by analyzing the receiver operating characteristic curve of the subjects.Results The visual analysis of image quality had a strong consistency between the two doctors(ICC=0.853,P<0.001).The images with acquisition time of 5 min could reach the common quality level in clinical work,accounting for 78.4%(40/51).The semi-quantitative results of image quality showed that there was no significant difference between SUVR and diagnostic efficiency obtained by acquisition time 5 min and 10 min(Z=1.821,P=0.069),and the best critical value of the two groups was equal to 3.Therefore,properly shortening the acquisition time had no effect on the diagnosis of Parkinson's disease.Conclusion With the development and advancement of technical equipment,PET image quality is gradually improving and the scanning time is also gradually shortening.The acquisition time for 18F-D6-AV133 can be shortened from the conventional 10 min to 5 min.

Research on MRE quality control in diagnosing intestinal diseases / 中国医学装备

Objective:To investigate the quality control of magnetic resonance enterography(MRE)in the diagnosis of intestine diseases,and analyze the factors that affected the imaging quality of MRE,and enhance the imaging quality of MRE through adopted the measures of quality control.Methods:The documents of MRE examinations of 167 patients with intestinal disease who admitted to the 900th Hospital of People's Liberation Army Joint Service Support Force from May 2018 to March 2023 were retrospectively analyzed.The image qualities of all patients were evaluated after they completed clinical and image examinations.The reasons that image quality could not meet the requirement of diagnosis were analyzed.And then,the measures of quality control were proposed.Results:In 167 patients with intestinal disease,the MRE images of 153 patients(91.62%)could meet the requirement of diagnosis.In 14 patients(8.38%)whose MRE images could not meet the requirement of diagnosis,the reason of 3 cases(1.80%)was poor respiratory coordination,and that of 2 cases(1.20%)was there were more severe magnetic sensitive artifacts in images,and that of 1 case(0.60%)was severe intestinal peristalsis leaded to blurred images,and that of 2 cases(1.20%)was the flow void effect from intestinal peristalsis inside of intestinal cavity could not meet the requirement of diagnosis,and that of 4 cases(2.40%)was the intestinal tube without incomplete dilation caused by poor oral filling contrast agent,and that of 2 cases(1.20%)was many residues in intestine due to poor preparation for intestine.Aimed at the factors that MRE images could not meet requirement of diagnosis,we proposed the following quality control measures:①the biphasic contrast agents with favorable safety,without severe adverse reactions,which can fully dilate intestinal cavity,should be selected.②we should do well for the dilation of intestinal tube,and inhibit the intestinal peristalsis and conduct respiratory training.③we should conduct scan with wide field at coronal site,so as to display panorama image of intestine.④The scans of conventionally anatomical sequence and functional imaging sequence on axis position were performed on lesions.Conclusion:MRE technique should choose appropriate contrast agent in the quality control of the diagnosis of intestine diseases,and do well the preparation for patients before examination.Using intraluminal contrast agents,conducting intestinal dilation and optimal imaging technique are essential for obtaining intestinal MRE images with high quality.

Study on the effects of AI reconstruction algorithm based on different tube voltages on CT imaging quality and radiation dose of chest phantom / 中国医学装备

Objective:To investigate the effects of different tube voltages combined with artificial intelligence reconstruction algorithm(CI)on the computed tomography(CT)imaging quality and radiation dose of chest phantom on the basis of the CT scan for an adult male simulated chest phantom(PH-N1).Methods:A 512-slice CT scanner of ultrahigh-end was adopted to conduct scan,and the images were divided into 70 kV group,80 kV group,100 kV group and 120 kV group according to different tube voltage.For 4 groups of CT scan images with different tube voltages,the 10%,30%,50%,70%and 90%CI were adopted to reconstruct 1mm thin layer image.The CT volume dose index(CTDIvol)and the dose-length product(DLP)of the scans of 4 groups were compared.The CT values and standard deviation(SD)values of the aorta,abdominal wall fat and erector spine muscle were measured.Two senior diagnostic physicians with more than 5 years of work experience independently and double-blindly evaluated the image quality by using 5-point scale.A Kappa consistency test was conducted.One-way analysis of variance was adopted to compare the differences of CT values and SD values of the tissues of image targets.The Friedman rank-sum test was adopted to compare the differences of subjective image qualities among different groups.Results:The differences of CTDIvol and DLP among 4 groups with different tube voltages were significant(F=1855.617,3996.118,P<0.05),respectively.Under 70 kV tube voltage,there were no significant differences in CT values of the aorta,abdominal wall fat and erector spine muscle,which were reconstructed by using 10%,30%,50%,70%and 90%CI(P>0.05),while the differences of SD values among them were statistically significant(F=32.267,53.327,14.873,P<0.05),respectively.Under the different tube voltages of 4 groups,which were reconstructed by 90%CI,the CT values of aorta,abdominal wall fat and erector spine muscle gradually decreased with decreasing of tube voltage,the differences were significant(F=139.899,2563.93,219.231,P<0.05),respectively.The consistency of subjective scores between two diagnostic physicians was better for each group of images(Kappa=0.712～0.869).Conclusion:Compared with 80 kV,90 kV and 120 kV images,the reconstructed images with 90%CI algorithm under 70 kV tube voltage can significantly reduce the radiation dose,and the images have a favorable signal-to-noise ratio at the same time.

Clinical value of wide body CT in chest scanning of patients under free breathing state / 中国医学装备

Objective:To explore the application value of compute tomography(CT)scan with 16cm wide body detector in chest examination of patients who could not cooperate with breath-holding.Methods:A total of 100 patients who could not cooperate with breath-holding during chest examination in the second affiliated hospital of Shenyang Medical College from May to August in 2022 were selected,and they were randomly divided into observation group and control group,with 50 patients in each group.The collimation width of CT scan with 16cm wide body detector was 256 mm×0.625 mm in the observation group,and that with 8 cm wide body detector was 128 mm×0.625 mm in the control group,and other parameters of two groups were same.A series of indicators included age,height,weight and body mass index(BMI)of patients were recorded,and the CT dose index(CTDIvol),dose length product(DLP),effective dose(ED)were measured and calculated.And then,the Contrast to Noise ratio(CNR),signal to noise(SNR)and Standard Deviation(SD)between two groups were compared,and the image quality was evaluated objectively and subjectively.Results:The average age and the average weight of the patients in the observation group were respectively(78.81±6.84)years old and(64.46±9.86)kg,and the mean values of BMI,CTDIvol,DLP,ED and exposure time were respectively(22.89±3.09)kg/m2,(4.61±1.00)mGy,(1 471.02±345.25)mGy·cm,(20.59±4.83)mSv,(1.01±0.61)s.The average age and the average weight of the patients in the control group were respectively(77.70±6.76)years old and(62.84±4.75)kg.The mean values of BMI,CTDIvol,DLP,Ed and exposure time were respectively(22.89±2.29)kg/m2,(14.5±0.00)mGy,(4 561.70±346.32)mGy·cm,(63.86±4.85)mSv and(4.07±0.12)s.The differences of subjective evaluations of main pulmonary artery,right inferior pulmonary vein trunk and aortic arch between the observation group and the control group were not significant(P>0.05).The subjective scores of image qualities both two groups were larger than 4,and the image qualities of two groups could meet the diagnostic requirements.The CTDIvol,DLP,ED and exposure time of observation group were significantly lower than those in control group(t=-69.42,-44.231,-44.234,-107.10,P<0.05),respectively.Conclusion:Compared with the CT scan with conventional 8 cm detector,the CT scan with 16 cm wide body detector can greatly shorten the scanning time and reduce the radiation dose in the chest CT scan of patients with free breathing,and the image quality of that can meet the requirement of clinical diagnosis,which has very high application value in the fast diagnosis of clinical emergency.

The value of spectral CT combined with metal artifact reduction algorithms in improving the CT image quality for patients with 125I seeds implantation in the chest and abdomen / 中华放射学杂志

Objective:To investigate the value of the virtual monoenergetic image (VMI) obtained by a new dual-layer detector spectral CT combined with metal artifact reduction algorithms(O-MAR) in reduction of different types of artifacts caused by 125I seeds implantation and in improvement of the post-operative CT image quality. Methods:This was a cross-sectional study. Thirty-five patients who underwent dual-layer detector spectral CT scanning of the chest and abdomen after 125I seeds implantation were retrospectively included at the First Affiliated Hospital of Zhengzhou University from March to September 2022. The spectral data were collected and reconstructed into conventional CT image (CI), VMI image (50-150 keV, 20 keV/level), CI+O-MAR image, and VMI+O-MAR image (50-150 keV, 20 keV/level). The artifacts′ removal effects and image quality improvement in each group were evaluated. Two slices with the strongest artifacts were selected for analysis for each patient, resulting in a total of 70 slices. Objective indicators including artifact index (AI), signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of soft tissue regions affected by artifacts were measured and calculated. Subjective indicators including the overcorrected artifacts and new artifacts, the different forms of artifacts, the diagnosis of artifacts, and the image quality were assessed. One-way analysis of variance was used for comparisons among multiple groups. Paired t test was used to compare the quantitative indicators between the combined O-MAR group and the non-O-MAR group. Kappa statistics was used to evaluate the consistency between observers. Results:In high/low-density artifacts (ROI H/L), the AI values in all groups showed decrease with increasing VMI keV. In artifact-affected tissue (ROI T), SNR of the CI/VMI (70-150 keV)+O-MAR group were significantly higher than those of the CI/VMI group ( P<0.05), CNR of the CI/VMI(50-150 keV)+O-MAR group were significantly higher than those of the CI/VMI group ( P<0.05). Both overcorrection and new artifacts mainly presented in VMI 50 keV and VMI 70 keV groups; Compared with VMI (50-70 keV) group, significantly less numbers of overcorrection and new artifacts were found in VMI (50-70 keV)+O-MAR group ( P<0.05); regarding the comparison of artifact types, with the VMI keV increasing, the number of a-type banded artifacts gradually decreased on images with high-density artifacts, reaching a minimum of 3 in the VMI 150 keV+O-MAR group; while the number of e-type artifacts with little or no artifacts increased, with the highest number of 23 in the VMI 150 keV+O-MAR group. The total number of high-density artifacts in each type decreased with increasing VMI keV. As VMI keV increased, the diagnostic and image quality scores of high-density artifacts in each group were significantly higher than those of low-density artifacts in the VMI+O-MAR group ( P<0.05). Conclusions:VMI combined with O-MAR can significantly improve the objective and subjective image quality of follow-up CT imaging after 125I seed implantation, enhancing lesion visibility and diagnostic confidence. Additionally, VMI+O-MAR showed more pronounced correction effect on high-density artifacts.

Application value of the deep learning-based image reconstruction algorithm in combined head and neck CT angiography with low radiation dose / 中华放射医学与防护杂志

Objective:To explore the differences between the deep learning-based image reconstruction (DLIR) and the adaptive statistical iterative reconstruction V (ASiR-V) algorithms in the radiation dose and image quality of head and neck CT angiography (CTA).Methods:The data of 80 patients undergoing head and neck CTA due to vascular diseases in the head and neck were prospectively collected. These patients were randomly divided into groups A and B based on their examination sequence. The CTA images of group A were reconstructed based on ASiR-V 50%, with a tube voltage of 120 kV and a noise index of 11.0. In contrast, those of group B were reconstructed based on ASiR-V 50% (for group B1) and DLIR-H (for group B2), with a tube voltage of 80 kV and a noise index of 9.0. Then, the radiation doses and image quality of both groups were compared using the independent-sample t-test. The radiation doses, and both subjective and objective image quality of the two imaging method were compared through the Kruskal-Wallis test and the Wilcoxon rank-sum test. The independent- or paired-sample t-test was employed to measure inter-group vascular enhanced CT values, as well as signals and noise from regions of interest (ROIs), with signal-to-noise ratios (SNRs) and contrast-to-noise ratios (CNRs) calculated. Results:The effective doses of groups A and B were (0.77±0.08) and (0.45±0.05) mSv, respectively, with a statistically significant difference ( t = 21.96, P < 0.001). The vascular enhanced CT values, SDs, SNRs, and CNRs in the arch of the aorta, the initial and bifurcation parts of the common carotid artery, and the M1 segment of the middle cerebral artery showed statistically significant differences among groups A, B1, and B2 ( F = 67.69, 68.50, 50.52, 74.10, 63.10, 91.22, 69.16, P < 0.001). Additionally, statistically significant differences were observed in the subjective scores of image quality among groups A, B1, and B2 ( Z = 71.06, P < 0.05). Conclusions:The DLIR algorithm can further reduce the radiation dose in head and neck CTA examination while significantly reducing image noise and ensuring image quality, thus demonstrating high clinical application value.

A study of the performance evaluation of iCBCT imaging mode / 中华放射肿瘤学杂志

Objective:To comprehensively evaluate the performance of the iterative cone beam CT (iCBCT) imaging mode of Varian linear accelerators and to explore its specific advantages in clinical application.Methods:The kV cone beam CT (CBCT) imaging systems of Halcyon 2.0, Edge, and VitalBeam linear accelerators from Tianjin Medical University Cancer Institute & Hospital were selected, among which Halcyon 2.0 and Edge were equipped with the iCBCT imaging mode. The Penta-Guide phantom was used to evaluate the registration accuracy of iCBCT imaging modes. The accuracy of treatment couch position was measured by a ruler. The image quality of the iCBCT and conventional CBCT modes of various imaging devices were analyzed using the CatPhan604 phantom. The imaging beam-on time and reconstruction time were measured to assess image acquisition efficiency. The uniformity, spatial resolution, contrast, contrast-to-noise ratio (CNR), image acquisition time and reconstruction time between two imaging modes were statistically analyzed by t-test. Results:The maximum deviations of image registration measurement results of the iCBCT mode for Halcyon 2.0 and Edge accelerators compared to the standard values were 0.7 mm and 0.6 mm, respectively. The treatment couch position error of all devices was less than 1 mm. The iCBCT images under head scanning protocol primarily improved the uniformity and CNR. Compared to conventional CBCT images, Halcyon iCBCT increased the uniformity and CNR by 2.50% ( P<0.001) and 78.85% ( P<0.001), respectively, while Edge increased them by 2.18% ( P<0.001) and 86.42% ( P<0.001), both superior to VitalBeam CBCT images. Under pelvis scanning protocols, iCBCT images primarily improved the CNR compared to conventional CBCT images. Halcyon and Edge iCBCT increased the CNR by 113.57% ( P<0.001) and 133.87% ( P<0.001), respectively, both superior to VitalBeam CBCT images. In terms of image acquisition efficiency, the average reconstruction times for Halcyon and Edge iCBCT images increased by 7.28 s and 15.53 s, respectively, and the total image acquisition time of Halcyon accelerator was the shortest. Conclusions:While ensuring the registration accuracy, iCBCT imaging mode can significantly improve the CNR of images and improve the uniformity of images under head scanning protocol. The Halcyon imaging system can enhance image acquisition efficiency.

The value of three-point localization method for four-chamber view acquisition in cardiac magnetic resonance imaging / 西安交通大学学报(医学版)

【Objective】 To evaluate the application value of the three-point localization method in improving the quality and efficiency of four-chamber view acquisition in cardiac magnetic resonance (CMR) imaging. 【Methods】 A total of 215 patients who underwent four-chamber view in CMR imaging from January 2022 to October 2023 were retrospectively enrolled and divided into two groups. The control group (n=109) received traditional localization method while the study group (n=106) received three-point localization method. The image quality of mitral valve, tricuspid valve and cruciform structure in four-chamber view images were assessed by two radiologists using a Likert 4-piont scale. The time-consumption from scout imaging to the finish of four-chamber view imaging was recorded. Constituent data and numeral data were compared by Chi-square test and two-sample t test, respectively. Kappa test was used to analyze the inter-observer consistency. 【Results】 There were no significant inter-group differences in gender, age, disease profile, or the radiographers’ experience. The mean quality scores of the mitral valve, tricuspid valve and cruciform structure in the control group and the study group were 3.44±0.64 and 3.63±0.49 (P=0.023), 3.43±0.67 and 3.53±0.60(P=0.202), 3.71±0.49 and 3.83±0.35 (P=0.047), respectively. The image quality score was higher in the study group than in the control group, with the differences in mitral valve and cruciform structure reaching statistical significance. The time-consumption for obtaining four-chamber view for the control group and the study group was 11.67±3.49 minutes and 7.212±1.83 minutes, respectively, with statistically significant differences (P<0.001). 【Conclusion】 Compared with the traditional localization method, the three-point localization method provides better image quality in four-chamber view imaging with shortened imaging time.

Application values of fixed tube current based on head circumference in children's head CT examinations / 实用放射学杂志

Objective To explore the application values of fixed tube current based on head circumference(HC)in children's head CT examinations.Methods A total of 573 children's head CT imaging data were collected retrospectively,the tube current and HC were recorded.Pearson's correlation analysis was used to determine the relationship of tube current with HC,counted the median tube current values of each group based on HC and used them as the prefixed tube current.Seventy-two children were prospectively collected.According to the random number table method,the children were divided into the control group and the experimental group,with 35 cases in the control group and 37 cases in the experimental group.The control group used automatic exposure control(AEC)technology for tube current,while the experimental group used the median value of tube current corresponding to HC group-ing.The difference in radiation doses and image qualities between the two groups was compared.Results Pearson analysis of 573 retrospec-tive cases showed that the correlation between HC and tube current was considerably strong(r=0.95,P＜0.001).The median tube current values of each group based on HC were 70-130 mAs.There were statistically significant differences in CTDIvol.16 and SSDEDW based on water equivalent diameter(DW)between the two groups(t=-11.27,2.81,P＜0.05).Compared with the control group,CTDIvol.16 and SSDEDW in the experimental group decreased by 10.83％and 12.59％respectively.There were no statistically signifi-cant differences in signal-to-noise ratio(SNR)between the two groups(t=-1.26,P＞0.05)and there were also no statistically significant differences in the subjective evaluation of images(Z=-0.45,P＞0.05).Conclusion Measuring children's HC before examination and setting the fixed tube current corresponding to HC grouping can reduce radiation doses while maintaining image qualities.

Application of deep learning image reconstruction combined with computer-aided diagnosis in CT screening of pulmonary nodules / 实用放射学杂志

Objective To analyze the effects of deep learning image reconstruction(DLIR)and adaptive statistical iterative recon-struction V(ASIR-V)on the imaging quality of chest CT in patient with pulmonary nodules,and to evaluate the differences based on different image reconstruction techniques in the detection of efficiency of computer-aided diagnosis(CAD)for pulmonary nodules.Methods The image data of pulmonary nodules of eighty patients with chest CT screening were reconstructed with ASIR-V 80％,DLIR-low(DLIR-L),DLIR-medium(DLIR-M)and DLIR-high(DLIR-H)images,respectively.The objective image quality and sub-jective image quality of the four groups were compared and analyzed.Objective image quality includes CT value of region of interest(ROI),noise,signal-to-noise ratio(SNR),contrast-to-noise ratio(CNR)and image average gradient.The diagnostic efficacy of CAD in detecting pulmonary nodules of reconstructed images among four groups were further evaluated.Results There were no signifi-cant difference in CT value of ROI of reconstructed images among the four groups(P＞0.05).The noise,SNR and CNR of DLIR-H images were similar to those of ASIR-V 80％(P＞0.05),but significantly better than those of DLIR-L and DLIR-M(P＜0.05).The average gradient of DLIR-L,DLIR-M and DLIR-H images were significantly higher than those of ASIR-V 80％(P＜0.05).The subjective image quality scores of DLIR-L,DLIR-M and DLIR-H images were significantly higher than those of ASIR-V 80％(P＜0.05),and the subjective image quality score of DLIR-H image was the highest.CAD showed the highest true positive rate in DLIR-H images for detecting pulmonary nodules(P＜0.05),and CAD showed the highest false positives per capita in ASIR-V 80％images for detecting pulmonary nodules(P＜0.05).Conclusion The noise,SNR and CNR of DLIR-H images are similar to those of ASIR-V 80％,with the significantly higher image clarity and subjective image quality scores.DLIR-H has advantages in CAD detection of pulmonary nodules,which is an ideal image reconstruction technology for chest CT pulmonary nodule screening.

Application of the second generation snap shot freeze combined with artificial intelligence in free heart rate coronary CT angiography / 实用放射学杂志

Objective To evaluate the application value of the second generation snap shot freeze(SSF2)combined with artificial intelligence reconstruction in free heart rate coronary computed tomography angiography(CCTA).Methods The examination data of 37 patients undergoing CCTA were divided into two groups for reconstruction.Group A,reconstruction by artificial intelligence after SSF2 algorithm correction;group B,original images automatically split and multi-phase reconstruction by artificial intelligence.Image quality were compared on volume rendering(VR),curve planar reformation(CPR),maximum intensity projection(MIP)image,subjective evaluation,objective scoring,and signal-to-noise ratio(SNR).Independent samples t-test and Chi-square test were used,and P<0.05 was considered statistically significant.Results There were statistically significant differences in the image quality score and SNR of the two reconstruction methods(P=0.009).Group A scored better,with higher signal intensity,lower noise intensity,and better SNR.The difference in the number of right coronary artery(RCA)analyzable segments between the two groups was statistically significant(P<0.05).The excellent and good rate of subjective evaluation of coronary artery segments in group A RCA(98.6%)was higher than that in group B(69.6%).Conclusion Using SSF2 combined with artificial intelligence reconstruction technology can significantly improve the image quality of CCTA,improve the success rate of CCTA examination,and improve the overall work efficiency.

Clinical diagnostic value of Fast Dixon technique in MR hip joint scan / 实用放射学杂志

Objective To explore the application value of Fast Dixon technique in MR hip joint scanning.Methods Fifty young volunteers were recruited to perform axial and coronal MR scans of the hip joint.The scanning sequence was Fast Dixon T2WI sequence and conventional Dixon T2WI sequence.A double-blind five-point scale was used to subjectively evaluate the image quality of the two types sequences.The signal-to-noise ratio(SNR)and contrast-to-noise ratio(CNR)of the axial image were measured at the maximum level of the bladder display.Results In the scores of"good contrast between surrounding tissue and femoral head signal"and"overall image quality",the Fast Dixon T2WI sequence was better than the conventional Dixon T2WI sequence,and the difference was statistically significant(P<0.05).There was no significant difference in the average scores of"whether bladder artifacts affected the diagnosis"and"whether the fat suppression effect was good"between Fast Dixon T2WI sequence and conventional Dixon T2WI sequence(P>0.05).In the objective image quality evaluation,the SNR and CNR of Fast Dixon T2WI sequence were better than those of conventional Dixon T2WI sequence,and the difference was statistically significant(P<0.05).Conclusion The image quality score of the hip joint of young volunteers with Fast Dixon T2WI sequence combined with multiple averaging excitation technique is significantly higher than that of conventional Dixon T2WI sequence.The Fast Dixon T2WI sequence can increase the effect of inhibiting fat and motion artifacts without increasing the scanning time,and the joint face ratio is good.Fast Dixon technique can replace the traditional Dixon technique,thus becoming an optimal choice for hip joint MR scanning.

PDCA cycle improves the image quality of oral photography in patients with periodontal disease / 中国现代医生

@#Objective To study the effect of PDCA cycle on the image quality of oral photography in patients with periodontal disease.Methods Totally 94 patients with periodontal disease admitted to our hospital from February to July 2022 were selected.47 patients who took oral photography images from February to April 2022 were included in the control group,and 47 patients who took oral photography images from May to July 2022 were included in the PDCA group.At the same time,9 nursing staff in the periodontal department of our hospital were selected.The patients in the control group were taken conventional photography,PDCA group used PDCA cycle on the basis of the control group.The image quality of the two groups of patients with periodontal disease and their satisfaction with the oral photography process were compared.The deduction of points for photography technology of nursing staff before and after the implementation of PDCA cycle were compared.Results The rate of reaching the standard of image quality in PDCA group was significantly higher than that in the control group(P<0.05).The satisfaction of PDCA group with oral photography was significantly higher than that of the control group(P<0.05).After the implementation of PDCA cycle,the deduction of points of material preparation,frontal,lateral,lingual,maxillofacial,maxillofacial,photography time and photography technology of nursing staff were significantly lower than those before the implementation(P<0.05).Conclusion PDCA circulation can effectively improve the rate of reaching the standard of oral photography image quality of patients with periodontal disease,increase their satisfaction with the photography process,and improve the nursing staff's photography technology score.

Image quality of CBCT under different exposure parameters / 实用口腔医学杂志

Objective:To investigate the imaging quality of CBCT under different exposure parameters and the relationship between subjective and objective evaluation.Methods:CBCT scanners of 6 different suppliers[3D Accuitomo(Morita),i-mCAT(Kavo),5G(NewTom),Smart3D(Beijing Langshi),DCT Pro(Vatech),Vgi(NewTom)]were used to scan the spatial resolution models and head simulators under typical exposure conditions(different device with different tube voltage and current for exposure).The visibility of SedentexCT IQ phantom and anatomical structures generated by different CBCT scanners were compared.For objective evaluation,7 professional evaluators scored CBCT imaging qualities.For subjective evaluation,the resolution(LP/mm)of the images were com-pared among the devices.Results:No significant difference was found by 7 evaluators either intra or inter of the teams.By objective e-valuation,the score of NewTom 5G was 2,that of i-CAT was 5 and that of the others was 4.By subjective evaluation,the LP/mm of i-CAT was 1.8,that of Smart3D was 2.0 and that of the others was 1.0-1.7.The subjective evaluation of image quality obtained un-der different tube voltages and tube currents were significantly different.Conclusion:The subjective and objective evaluations of image quality are approximately consistent.The difference of the subjective image quality may be produced by the different tube voltage and current for exposure.

Determinación de la calidad de imágenes clínicas de proyecciones postero anterior y lateral de tórax / Determination of clinical image quality of posteroanterior and lateral chest images

RESUMEN Los estudios radiológicos son fundamentales en el diagnóstico y tratamiento de diversas patologías. Su calidad depende de múltiples variables, entre las que destacan, los parámetros de adquisición, interpretación, entre otros. Se propone una metodología estandarizada, sencilla, de fácil interpretación, permitiendo la evaluación regular de la calidad de las imágenes, dando indicios de la propiedad del trabajo en el centro de salud y poder realizar comparaciones entre centros y autores, a partir de los criterios anatómicos establecidos por la Unión Europea, definiendo el parámetro de calidad de la imagen (CI), representadas en una escala de Likert para el análisis de frecuencia, demostrando que puede ser una herramienta de utilidad para la evaluación reiterada de los centros de radiología. Evaluando 140 proyecciones postero anterior y 85 laterales de tórax, con una muestra de 225 estudios, realizados en un centro de salud, ubicado en la ciudad de Mérida, República Bolivariana de Venezuela, escogiendo estas proyecciones, ya que, representan el 32% de los estudios de radiología convencional. Permitiendo la comparación entre proyecciones y autores, obteniéndose para la proyección postero anterior un CI de 5,07 ± 1,53 criterios de los ocho establecidos, normalizado un CI de 0,62 ± 0,19; las imágenes excelentes solo representan el 22,78%. Comparado con un CI de 4,91 ± 1,17 criterios de los seis establecidos, normalizado un CI de 0,82 ± 0,19, e imágenes excelentes en un 64,71% para la proyección lateral. Se observa las notorias diferencias entre la calidad de las imágenes clínicas en hombres y mujeres para ambas proyecciones

ABSTRACT Radiological studies are essential in the diagnosis and treatment of various pathologies. Their quality depends on multiple variables, among which the acquisition and interpretation parameters, among others, stand out. A standardized methodology is proposed, simple, of easy interpretation, allowing the regular evaluation of the quality of the images, giving indications of the property of the work in the health center and being able to make comparisons between centers and authors, from the anatomical criteria established by the European Union, defining the parameter of image quality (IQ), represented on a Likert scale for frequency analysis, demonstrating that it can be a useful tool for the repeated evaluation of radiology centers. Evaluating 140 postero anterior and 85 lateral projections of the thorax, with a sample of 225 studies, performed in a health center, located in the city of Merida, Bolivarian Republic of Venezuela, taking these projections, since they represent 32% of the conventional radiology studies. Allowing the comparison between projections and authors, obtaining for the postero anterior projection an IQ of 5.07 ± 1.53 criteria of the eight established, normalized an IQ of 0.62 ± 0.19; the excellent images only represent 22.78%. Compared with an IQ of 4.91 ± 1.17 criteria of the six established, normalized IQ of 0.82 ± 0.19, and excellent images in 64.71% for the lateral projection. It is observed the notorious differences between the quality of clinical images in men and women for both projections

Comprobación del control automático de exposición en el tomógrafo Canon Aquilion ONE / Verification of the automatic exposure control on the Canon Aquilion ONE tomograph

Resumen Dado el uso incrementado de la tomografía computarizada en la Caja Costarricense del Seguro Social durante los últimos 10 años, se ha vuelto cada vez más importante obtener imágenes de la calidad diagnóstica requerida con la mínima dosis de radiación posible al paciente. Para lograr esto, en los sistemas de tomografía computarizada se utiliza, rutinariamente, el control automático de exposición, el cual modula la corriente del tubo según la atenuación del haz que produce el paciente y que se obtiene en el escanograma. Objetivo: Comprobar el funcionamiento del control automático de exposición de un tomógrafo Canon Aquilion ONE en la dosis suministrada al paciente y verificar la importancia de realizar un simple o doble escanograma para diferentes protocolos clínicos. Métodos: Se analizó el comportamiento de la dosis, el ruido y la intensidad de la corriente obtenida en un maniquí con diferentes secciones elípticas que varían sus dimensiones en los ejes X-Y. Se determinó el producto dosis longitud en diferentes protocolos clínicos con el control automático de exposición activado debido a un simple o doble escanograma. Resultados: Para intensidades de corrientes fijas, a medida que aumenta el tamaño de cada sección del maniquí, la dosis se reduce, aproximadamente hasta el 72% y, cuando disminuye el tamaño de cada sección, mejora hasta en un 21% la calidad de la imagen debido a la reducción del ruido. Conclusiones: Se pudo observar que, a pesar de que las dosis para localización son bajas, la utilización de un simple escanograma, en la mayoría de los protocolos, no solo permite reducir la dosis suministrada al paciente, sino también efectuar menor cantidad de disparos en el equipo e incrementar la vida útil del tubo de rayos X, pues el aporte de un segundo escanograma no representa un impacto significativo en la calidad de imagen.

Abstract Given the increased use of computed tomography in the Costa Rican Social Security Fund during the last 10 years, it has become increasingly important to obtain images of the required diagnostic quality with the minimum radiation dose to the patient. To achieve this, computed tomography systems routinely use automatic exposure control, modulating the tube current according to the attenuation of the beam produced by the patient and obtained on scanogram. Aim: Check the operation of the automatic exposure control of a Canon Aquilion ONE scanner at the dose delivered to the patient and to verify the importance of performing a single or double scanogram for different clinical protocols. Methods : The behavior of the dose, the noise and the intensity of the current was analyzed in a phantom with different elliptical sections that vary their dimensions in the X-Y axes. The dose-length product was determined in different clinical protocols with the automatic exposure control activated due to a single or a double scanogram. Results: For fixed current intensities, as the size of each section of the phantom increases, the dose is reduced, approximately, up to 72% and when the size of each section decreases, the quality of image improves, due to noise reduction, up to 21%. Conclusions: It was observed that, despite the fact that the doses for localization are low, the use of a simple scanogram in most protocols not only reduces the dose to the patient, but also makes fewer shots in the equipment and increases the useful life of the X-ray tube, since the contribution of a second scanogram does not represent a significant impact on image quality.