Purpose To measure the spatial resolution in MRI quality control testing automatically based on the American College of Radiology(ACR)phantom using the support vector machine(SVM)method,and the feasibility,accuracy and measurement speed of this method are explored.Materials and Methods Quality control tests were performed using eight MRI devices at Beijing Friendship Hospital of Capital Medical University.A retrospective study was conducted on 71 MRI quality control test images collected based on ACR phantoms between 2017 and 2019.The images were preprocessed by binarization,extraction region of interest and so on.An SVM-based classification model was constructed for analyzing the spatial resolution of dot arrays in row and column directions.The dataset was randomly split into a training set and a test set.The generalization performance of the classification model in this study was evaluated through accuracy,precision,recall and F1 score on the test set.Comparing the results of spatial resolution measurements obtained by both manual and automatic method,we demonstrated the feasibility and accuracy of the method.Additionally,the time taken for the automatic spatial resolution measurement was recorded.Results In this study,the proposed method of automatically measuring the spatial resolution of ACR phantom test images using SVM was feasible,high accuracy and short time.In classification performance test,the accuracy of the spatial resolution of the row directional latices was 95%,the precision was 100%.The accuracy of the spatial resolution of the column directional latices was 97%,the precision was 100%.Among the test cases,the results of automatic measurements matched those of manual measurements in 13 out of 14 cases.On average,automatic spatial resolution measurement took 0.158 seconds per case.Conclusion This study achieves automatic measurement of spatial resolution in MRI quality control based on the ACR phantom using SVM method.The method demonstrates high accuracy and fast measurement speeds,holding significant implications for future rapid MRI quality control stability testing.

Purpose To explore an automatic detection method for quality control performance indicators of radio frequency coils based on American College of Radiology(ACR)phantom,and verify its accuracy stability and computational efficiency.Materials and Methods A retrospective study was conducted on 50 quality control images collected based on ACR phantom in Beijing Friendship Hospital,Capital Medical University from May 2017 to July 2019.The measurement and calculation methods of signal noise ratio(SNR),percent image uniformity(PIU)and percent signal ghosting(PSG)were used to automatically calculate the above indicators using a self-designed program in Python.A simple linear regression analysis on the automatically calculated SNR,PSG and PIU values compared to the manually measured results was performed,and Bland-Altman analysis was used to calculate the percentage difference to evaluate the consistency and bias between the performance indicators calculated by the two methods.The time consumption of two detection methods was compared to verify their computational complexity and efficiency.Results There was a strong correlation between the performance indicators SNR,PSG and PIU of radio frequency coils measured and calculated automatically and manually(r=0.991 4,0.992 8 and 0.909 8,all P<0.0001).The Bland-Altman results showed that most of the data fall within the 95%confidence interval and were evenly distributed.In terms of computational complexity and efficiency,compared to the complex manual delineation and calculation of 2-3 minutes per case,automatic detection could simultaneously obtain SNR,PSG and PIU values in less than 1 second.Conclusion The automatic and manual measurement methods have good consistency,and the automatic detection method is easy to operate,which is helpful for the daily quality control work and performance monitoring of radio frequency coils.

Purpose To measure the spatial resolution in MRI quality control testing automatically based on the American College of Radiology(ACR)phantom using the support vector machine(SVM)method,and the feasibility,accuracy and measurement speed of this method are explored.Materials and Methods Quality control tests were performed using eight MRI devices at Beijing Friendship Hospital of Capital Medical University.A retrospective study was conducted on 71 MRI quality control test images collected based on ACR phantoms between 2017 and 2019.The images were preprocessed by binarization,extraction region of interest and so on.An SVM-based classification model was constructed for analyzing the spatial resolution of dot arrays in row and column directions.The dataset was randomly split into a training set and a test set.The generalization performance of the classification model in this study was evaluated through accuracy,precision,recall and F1 score on the test set.Comparing the results of spatial resolution measurements obtained by both manual and automatic method,we demonstrated the feasibility and accuracy of the method.Additionally,the time taken for the automatic spatial resolution measurement was recorded.Results In this study,the proposed method of automatically measuring the spatial resolution of ACR phantom test images using SVM was feasible,high accuracy and short time.In classification performance test,the accuracy of the spatial resolution of the row directional latices was 95%,the precision was 100%.The accuracy of the spatial resolution of the column directional latices was 97%,the precision was 100%.Among the test cases,the results of automatic measurements matched those of manual measurements in 13 out of 14 cases.On average,automatic spatial resolution measurement took 0.158 seconds per case.Conclusion This study achieves automatic measurement of spatial resolution in MRI quality control based on the ACR phantom using SVM method.The method demonstrates high accuracy and fast measurement speeds,holding significant implications for future rapid MRI quality control stability testing.

Purpose To explore an automatic detection method for quality control performance indicators of radio frequency coils based on American College of Radiology(ACR)phantom,and verify its accuracy stability and computational efficiency.Materials and Methods A retrospective study was conducted on 50 quality control images collected based on ACR phantom in Beijing Friendship Hospital,Capital Medical University from May 2017 to July 2019.The measurement and calculation methods of signal noise ratio(SNR),percent image uniformity(PIU)and percent signal ghosting(PSG)were used to automatically calculate the above indicators using a self-designed program in Python.A simple linear regression analysis on the automatically calculated SNR,PSG and PIU values compared to the manually measured results was performed,and Bland-Altman analysis was used to calculate the percentage difference to evaluate the consistency and bias between the performance indicators calculated by the two methods.The time consumption of two detection methods was compared to verify their computational complexity and efficiency.Results There was a strong correlation between the performance indicators SNR,PSG and PIU of radio frequency coils measured and calculated automatically and manually(r=0.991 4,0.992 8 and 0.909 8,all P<0.0001).The Bland-Altman results showed that most of the data fall within the 95%confidence interval and were evenly distributed.In terms of computational complexity and efficiency,compared to the complex manual delineation and calculation of 2-3 minutes per case,automatic detection could simultaneously obtain SNR,PSG and PIU values in less than 1 second.Conclusion The automatic and manual measurement methods have good consistency,and the automatic detection method is easy to operate,which is helpful for the daily quality control work and performance monitoring of radio frequency coils.

Objective:To investigate the influence of left atrial size on the ablation efficacy, cardiac morphology and function after valve replacement combined with X-type radiofrequency ablation on posterior wall of left atrium.Methods:From January 2015 to December 2019, 416 patients with mitral valve disease complicated with atrial fibrillation were divided into two groups according to the size of left atrium(Anteroposterior diameter 60 mm). Valve replacement combined with " X" radiofrequency ablation on posterior wall of left atrium was performed. The clinical data were analyzed retrospectively.Results:Except for the AF types, gender, length of stay and postoperative complications, other clinical data, operative and perioperative indicators were better in small left atria group(SLA)than in large left atria group(LLA). The differences were statistically significant( P<0.05). Fractional shortening(FS), ejection fraction(EF) in SLA at any time point were higher than that in LLA, P<0.05. The sinus rhythm conversion rates, the change rate of LA anteroposterior diameter in SLA at postoperative time points were higher than that in LLA, P<0.05. There was no significant difference of cardiac troponin(cTn) and myoglobin(MYO) between the two groups in 6 months after operation, P>0.05. The B-type natriuretic peptide(BNP), cTn, MYO in the other time points were lower than that in LLA, P<0.05. Conclusion:Larger left atrium reduces the rate of sinus rhythm conversion and maintenance in patients undergoing valve replacement combined with fibrillation ablation. There were worse ventricular remodeling and cardiac function recovery. Preoperative evaluation of left atrial size is helpful for prognosis.

Objective Big endothelin-1(big ET-1) is associated with the prognosis of various cardiovascular diseases. This study is to explore the predictive value of plasma big ET-1 level for long-term outcome after mitral valvuloplasty in patients with moderate to severe chronic ischemic mitral insufficiency .Methods A total of 142 consecutive patients with moderate to severe chronic ischemic mitral regurgitation who underwent coronary artery bypass grafting and mitral valvuloplasty were enrolled at our center from January 2009 to December 2015.The clinical baseline data were collected and recorded.All patients were followed up.The mortalities and major adverse cardiovascular and cerebrovascular events during the follow-up period were re-corded.Results A total of 142 patients were enrolled, with mean age of(59.4 ±8.3) years.During(51.9 ±22.6) months follow-up, 19 cases(13.4％) died and 35 cases(24.6％) had major adverse cardiovascular and cerebrovascular events.Uni-variate and multivariate Cox regression analysis showed that big ET-1 was an independent risk factor for all-cause mortality (HR=3.970, 95％CI:1.535-10.268) and major adverse cardiovascular and cerebrovascular events(HR=2.754, 95％CI:1.238-6.129).In addition, left ventricular ejection fraction, pulmonary hypertension and stroke history were independent risk factors for all-cause mortality , while left ventricular ejection fraction , stroke history were independent risk factors for major adverse cardiovascular and cerebrovascular events.Conclusion Long-term outcomes of simultaneous coronary artery bypass grafting and mitral valvuloplasty for moderate to severe ischemic mitral insufficiency are satisfactory and big ET-1 is an inde-pendent risk factor for long-term outcomes of these patients.

Objective To investigate the assessment of multi-detector spiral CT on the cardiac function after bioprosthetic valve replacement with mitral valve preservation.Methods Thirty-five patients suitable for undergoing bioprosthetic mitral valve replacement in our hospital from May 2012 to February 2014 were randomly divided into 2 groups:group A(experimental group,intraoperative preservation of mitral valve and subvalvular structure during,n=16) and group B (control group,without intraoperative preservation of subvalvular structure of mitral valve,n=19).MDCT before operation and on postoperative 10 d was performed for evaluating the left ventricular function.Results In the comparison of preoperative MDCT,the end diastolic velocity(EDV),end systolic velocity(ESV),ejection fraction(EF) and stroke volume(SV) had no statistical difference between the group A and B.In MDCT results on postoperative 10 d,EDV,ESV and EF in the group A were 113.42±9.22)mL,(38.63±3.40)mL and (51.63±4.71) ％,which in the group B were(113.42 ± 9.22) mL,(38.63 ± 3.40) mL and (51.63 ± 4.71) ％ respectively,the difference was statistically significant(P＜0.05),but SV had no statistical difference between the two groups(P＞0.05).Conclusion The bioprosthetic valve replacement with mitral valve preservation is safe and feasible in technology,moreover effectively protects the postoperative left ventricular function.

The aim of the study was to prepare enrofloxacin nanosuspension injection and evaluate its pharmacokinetics after giving a single intramuscular injection.The high pressure homogeneous technique was used to prepare enrofloxacin nanosuspension injection and preliminary evaluation of the quality was done.The high performance liquid chromatography (HPLC) method was used to determinate content of enrofloxacin in pig plasma.And the pharmacokinetic characteristics of enrofloxacin nanosuspension injection were compared with Baytril injection.The content of enrofloxacin in this preparation is 97.9％.The average particle size of enrofloxacin nanosuspension injection was (613.21±5.78) nm,PDI was (0.22±0.02) and the potential was-2.02 mV.Maximal plasma concentrations were (0.32±0.12) and (0.67 ± 0.09) mg/L after i.m administration with enrofloxacin nanosuspension injection and Baytril injection.The peak times were (2.88 ±0.96) and (0.79±0.26) hours,respectively.Mean elimination half-lifes were (5.99± 1.37) and (4.49 ± 1.25) hours,respectively.Areas under concentration-time curve were (4.63±1.30) and (4.40±0.45) mg/L · h,respectively.Mean residence times were (9.59±2.34) and (5.41±1.10) hours,respectively.The relative bioavailability of enrofloxacin nanosuspension injection was 105.2％.The preparation method of high pressure homogeneous was simple and good reproducibility.Enrofloxacin nanosuspension injection was characterized by non-sedimentation,easy-redispersion,relatively stable.Comparing with Baytril injection,enrofloxacin nanosuspension injection had a certain slowrelease effect,showing slower elimination than enrofloxacin injeetion.