ObjectiveTo delineate imaging findings using an imaging platform and investigate the correlation between MRI characteristics of spinal cord atrophy and clinical diagnosis in children with spinal cord injury (SCI). MethodsImaging data of 150 children with SCI admitted to Beijing Bo'ai Hospital, China Rehabilitation Research Center, from January, 2002 to March, 2024 were collected and imported into the imaging platform. The anteroposterior and transverse diameters of the middle part of the spinal cord at the cross-section with the most severe atrophy were measured, and the relevant indicators of the previous normal spinal cord segment were measured as controls; the radiomic features were extracted. Clinical data of the children including gender, age, cause of injury, sensory level, motor level, spinal cord injury level, injury severity and disease course were collected. ResultsSpinal cord atrophy was identified in 81 cases (54%), among which 78 cases (96%) were American Spinal Injury Association Impairment Scale (AIS) grade A and 3 cases (4%) were AIS grade C. The upper boundary of the spinal cord atrophy site strongly correlated with the injury level, motor level and sensory level (r > 0.8, P < 0.001). ConclusionMore than half of children with SCI may develop secondary spinal cord atrophy, the vast majority of whom suffer from complete spinal cord injury; the upper boundary of spinal cord atrophy is correlated with the injury level.

Three evaluation methods were recommended for the key properties of the intravascular catheter lubricating coating such as stability,lubricity and integrity,including insoluble particle test method,friction test procedure and appearance detection method.Fifteen batches of microcatheters produced by different manufacturers were selected for testing to clarify the three methods in test principle,step,result,characteristic.References were provided for the design,production,evaluation and regulation of intravascular catheters with lubricant coatings.[Chinese Medical Equipment Journal,2025,46(1):66-72]

Objective:To analyze the differences between subjective refraction and autorefraction in myopic children and adolescents under different ciliary muscle functional states.Methods:A cohort study was conducted.A total of 98 myopic children and adolescents (196 eyes) aged 7-15 years who visited the Shanghai Eye Disease Prevention and Treatment Center from November 2023 to February 2024 were included by random sampling.All participants underwent cycloplegia with 1.0% cyclopentolate and completed both subjective refraction and autorefraction before cycloplegia, after cycloplegia and after recovery from cycloplegia.The spherical equivalent (SE) differences and differences in SE(ΔSE) between different conditions were compared.Proportion of ΔSE, differences in spherical power (ΔS), and differences in cylindrical power (ΔC) of objective and subjective refraction between different conditions within the clinically acceptable error range (-0.25 to 0.25 D) was calculated and compared.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of Shanghai Eye Diseases Prevention & Treatment Center (No.2021SQ021).Written informed consent was obtained from guardian of each subject before any medical examination.Results:The SE values obtained from autorefraction before cycloplegia, after cycloplegia, and after recovery from cycloplegia were -2.44(-3.47, -1.63), -2.13(-3.25, -1.50), and -2.38(-3.50, -1.66)D, respectively, with a statistically significant overall difference ( χ2=148.36, P<0.001) and statistically significant differences in pairwise comparisons at different time points (all P<0.001); for subjective refraction, the SE values were -2.25(-3.50, -1.50), -2.19(-3.47, -1.45), and -2.28(-3.50, -1.50)D, respectively, with a statistically significant overall difference ( χ2=43.48, P<0.001) and statistically significant differences in pairwise comparisons at different time points (all P<0.001).Subjective refraction ΔSE between before and after cycloplegia, after cycloplegia and after recovery from cycloplegia were significantly smaller than those of autorefraction ( t=2.84, 1.82; both P<0.001).There was no significant difference in ΔSE between subjective refraction and autorefraction between before cycloplegia and after recovery from cycloplegia ( t=-0.43, P=0.070).The proportions of subjective refraction ΔSE within the acceptable error range between before and after cycloplegia, before cycloplegia and after recovery from cycloplegia, and after cycloplegia and after recovery from cycloplegia were significantly higher than those of autorefraction ( χ2=28.32, 11.82, 25.55; all P<0.001).The proportion of subjective refraction ΔS and ΔC both within the acceptable error range between before cycloplegia and after recovery from cycloplegia was 81.63%(160/196) and 79.59%(156/196) between after cycloplegia and after recovery from cycloplegia. Conclusions:Subjective refraction is less affected by different ciliary muscle functional states.The differences in subjective refraction results under different ciliary muscle functional states are mostly within the acceptable error range.The subjective refraction results before or after cycloplegia can be used to better predict the subjective refraction results after recovery from cycloplegia.

Objective:To analyze the differences between subjective refraction and autorefraction in myopic children and adolescents under different ciliary muscle functional states.Methods:A cohort study was conducted.A total of 98 myopic children and adolescents (196 eyes) aged 7-15 years who visited the Shanghai Eye Disease Prevention and Treatment Center from November 2023 to February 2024 were included by random sampling.All participants underwent cycloplegia with 1.0% cyclopentolate and completed both subjective refraction and autorefraction before cycloplegia, after cycloplegia and after recovery from cycloplegia.The spherical equivalent (SE) differences and differences in SE(ΔSE) between different conditions were compared.Proportion of ΔSE, differences in spherical power (ΔS), and differences in cylindrical power (ΔC) of objective and subjective refraction between different conditions within the clinically acceptable error range (-0.25 to 0.25 D) was calculated and compared.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of Shanghai Eye Diseases Prevention & Treatment Center (No.2021SQ021).Written informed consent was obtained from guardian of each subject before any medical examination.Results:The SE values obtained from autorefraction before cycloplegia, after cycloplegia, and after recovery from cycloplegia were -2.44(-3.47, -1.63), -2.13(-3.25, -1.50), and -2.38(-3.50, -1.66)D, respectively, with a statistically significant overall difference ( χ2=148.36, P<0.001) and statistically significant differences in pairwise comparisons at different time points (all P<0.001); for subjective refraction, the SE values were -2.25(-3.50, -1.50), -2.19(-3.47, -1.45), and -2.28(-3.50, -1.50)D, respectively, with a statistically significant overall difference ( χ2=43.48, P<0.001) and statistically significant differences in pairwise comparisons at different time points (all P<0.001).Subjective refraction ΔSE between before and after cycloplegia, after cycloplegia and after recovery from cycloplegia were significantly smaller than those of autorefraction ( t=2.84, 1.82; both P<0.001).There was no significant difference in ΔSE between subjective refraction and autorefraction between before cycloplegia and after recovery from cycloplegia ( t=-0.43, P=0.070).The proportions of subjective refraction ΔSE within the acceptable error range between before and after cycloplegia, before cycloplegia and after recovery from cycloplegia, and after cycloplegia and after recovery from cycloplegia were significantly higher than those of autorefraction ( χ2=28.32, 11.82, 25.55; all P<0.001).The proportion of subjective refraction ΔS and ΔC both within the acceptable error range between before cycloplegia and after recovery from cycloplegia was 81.63%(160/196) and 79.59%(156/196) between after cycloplegia and after recovery from cycloplegia. Conclusions:Subjective refraction is less affected by different ciliary muscle functional states.The differences in subjective refraction results under different ciliary muscle functional states are mostly within the acceptable error range.The subjective refraction results before or after cycloplegia can be used to better predict the subjective refraction results after recovery from cycloplegia.

Objective To quantify the volume and movement of cardiac substructures by using coronary computed tomography angiography(CCTA)to provide guidance for the design of deep inspiratory breath-holding radiation therapy for left breast cancer and the protection of organs at risk.Methods Totally 18 female patients who received conventional chest plain scan and CCTA were selected to simulate the design process of radiotherapy plan for left breast cancer patients with internal mammary lymph nodes.Retrospective reconstruction of CCTA data was performed for each patient,with 10 phase images(with an interval of 10％)within a R-R cardiac cycle(10％-100％)to simulate the true range of motion of the heart.The heart,left atrium(LA),left ventricle(LV),right atrium(RA),right ventricle(RV),left anterior descending artery(LAD),left circumflex coronary artery(LCX)and right coronary artery(RCA)were contoured at each phase.The distances from the centroid position to the average position of LAD,LCX and RCA were measured at each phase in the superior-inferior(SI),anterior-posterior(AP)and left-right(LR).The average volume and range of volume changes of LA,LV,RA,RV and heart were analyzed within a cardiac cycle.The expansion margins of planning organs at risk volume(PRV)were calculated.SPSS 19.0 software was used for statistical analysis.Results The following average absolute displacements were found in SI,AP and LR coordinates:(1.8±0.7)mm,(1.2±0.5)mm and(1.5±0.5)mm for LAD,respectively;(2.1±0.7)mm,(1.5±0.6)mm and(1.9±0.7)mm for LCX,respectively;(1.6±0.5)mm,(2.2±0.9)mm and(2.2±0.8)mm for RCA,respectively.The volume changes of LA,LV,RA,RV and heart within a cardiac cycle ranged from 34.3 to 63.9 cm3,122.1 to 154.3 cm3,29.3 to 53.6 cm3,57.2 to 94.3 cm3 and 480.1 to 515.4 cm3,respectively.The theoretical expansion margins of LAD,LCX and RCA in all the three directions were within 2 mm.Conclusion The ranges of movement and volume changes of cardiac substructure are quantitati-vely displayed,and references are provided for the planning of deep inspiratory breath-holding radiation therapy for left breast cancer and the protection of organs at risk.[Chinese Medical Equipment Journal,2025,46(3):54-58]

Objective By observing and measuring the relevant data of the buccal branch of the facial nerve,the parotid duct and the facial artery,the positional relationship among the three was analyzed to avoid accidental injury to the buccal branch of the facial nerve and the parotid duct when ligaturing the facial artery during the operation.Methods Forty adult head and neck specimens were dissected to observe the relationship between the buccal branch of the facial nerve and the parotid duct,the course and positional relationship of the facial artery,and the relationship between the buccal branch of the facial nerve and the peripheral vascular network.The relevant diameters were measured with a vernier caliper.Results The buccal branch of the facial nerve was divided into the superior buccal branch and the inferior buccal branch,and there was no direct anastomosis or connecting fiber between the buccal branch of the facial nerve and the parotid duct.The superior buccal branch was relatively thick,and it has a relatively constant position,which was parallel to the parotid duct.The position of the inferior buccal branch was not constant and it ran on or slightly above the plane of angulus oris.The superior buccal branch was located(10.76±5.54)mm from the parotid duct,while the inferior buccal branch was positioned(6.84±4.06)mm away from the parotid duct.The course of the main trunk of the facial artery was relatively fixed.Moreover,if the branch of the facial artery was missing,other branches of the facial artery would extend to replace the missing branch artery.The main trunk of the facial artery had a diameter of(2.34±0.83)mm,and its branches formed anastomoses with the buccal branch of the maxillary artery,creating a vascular network in the parotid and buccal regions.There was a vascular network around the buccal branch of the facial nerve,which was mostly small branches of the facial artery and the superficial temporal artery.Conclusion The buccal branch of the facial nerve exhibits a consistent anatomic relationship with the parotid duct and the facial artery.During the ligation of the facial artery,the parotid duct can serve as a landmark to accurately locate the buccal branch of the facial nerve,thereby significantly reducing the risk of inadvertent injury to the buccal branch of the facial nerve and the parotid duct.

Objective To deeply understand the anatomical basis of temporomandibular joint disorders,and explore and master the pathological characteristics of anterior displacement of temporomandibular joint disc through cadaveric dissection and 3D printing technology.Methods By dissecting the temporomandibular joints of 40 head and neck specimens,the bilateral structures of the temporomandibular joints were measured to obtain condyle and articular disc data.3D modeling was carried out using 3ds Max software and printed out a model of temporomandibular joint.The pathological model of the anterior disc displacement with reduction(ADDwR)was simulated by adjusting the opening degree,the position of the articular disk,and the position of the condyle of the model.Results The precise data of the right and left temporomandibular joint discs and condyle were successfully obtained by dissection and measurement.The thickness of the anterior band of left temporomandibular joint discs was(2.02±0.57)mm,the thickness of the middle band was(1.46±0.33)mm,the thickness of the posterior band was(3.00±0.46)mm,the anterior-posterior diameter was(9.60±0.72)mm,and the internal-external diameter was(17.73±0.84)mm.While the thickness of the anterior band of right temporomandibular joint discs was(1.84±0.35)mm,and the thickness of the middle band was(1.43±0.28)mm,the thickness of posterior band was(3.08±0.49)mm,the anterior-posterior diameter was(9.30±0.88)mm,and the internal-external diameter was(17.38±1.10)mm.The internal-external diameter of the left temporomandibular joint condyle was(18.97±0.41)mm,and the anterior-posterior diameter was(8.56±0.43)mm;the internal-external diameter of the right temporomandibular joint condyle was(18.86±0.75)mm,and the anterior-posterior diameter was(8.40±0.30)mm.The standard temporomandibular joint model was printed out by the measured data.The model was utilized to simulate the physiological state of temporomandibular joint under normal conditions,as well as the three pathological states of closed mouth,closed mouth to open mouth,and open mouth in the case of ADDwR.Conclusion The temporomandibular joint model can more intuitively present the changes of anatomical structure in reversible temporoman-dibular joint disorders,which is helpful for understanding and mastering the different classification of this disease.

Objective By observing and measuring the relevant data of the buccal branch of the facial nerve,the parotid duct and the facial artery,the positional relationship among the three was analyzed to avoid accidental injury to the buccal branch of the facial nerve and the parotid duct when ligaturing the facial artery during the operation.Methods Forty adult head and neck specimens were dissected to observe the relationship between the buccal branch of the facial nerve and the parotid duct,the course and positional relationship of the facial artery,and the relationship between the buccal branch of the facial nerve and the peripheral vascular network.The relevant diameters were measured with a vernier caliper.Results The buccal branch of the facial nerve was divided into the superior buccal branch and the inferior buccal branch,and there was no direct anastomosis or connecting fiber between the buccal branch of the facial nerve and the parotid duct.The superior buccal branch was relatively thick,and it has a relatively constant position,which was parallel to the parotid duct.The position of the inferior buccal branch was not constant and it ran on or slightly above the plane of angulus oris.The superior buccal branch was located(10.76±5.54)mm from the parotid duct,while the inferior buccal branch was positioned(6.84±4.06)mm away from the parotid duct.The course of the main trunk of the facial artery was relatively fixed.Moreover,if the branch of the facial artery was missing,other branches of the facial artery would extend to replace the missing branch artery.The main trunk of the facial artery had a diameter of(2.34±0.83)mm,and its branches formed anastomoses with the buccal branch of the maxillary artery,creating a vascular network in the parotid and buccal regions.There was a vascular network around the buccal branch of the facial nerve,which was mostly small branches of the facial artery and the superficial temporal artery.Conclusion The buccal branch of the facial nerve exhibits a consistent anatomic relationship with the parotid duct and the facial artery.During the ligation of the facial artery,the parotid duct can serve as a landmark to accurately locate the buccal branch of the facial nerve,thereby significantly reducing the risk of inadvertent injury to the buccal branch of the facial nerve and the parotid duct.

Three evaluation methods were recommended for the key properties of the intravascular catheter lubricating coating such as stability,lubricity and integrity,including insoluble particle test method,friction test procedure and appearance detection method.Fifteen batches of microcatheters produced by different manufacturers were selected for testing to clarify the three methods in test principle,step,result,characteristic.References were provided for the design,production,evaluation and regulation of intravascular catheters with lubricant coatings.[Chinese Medical Equipment Journal,2025,46(1):66-72]

Objective To deeply understand the anatomical basis of temporomandibular joint disorders,and explore and master the pathological characteristics of anterior displacement of temporomandibular joint disc through cadaveric dissection and 3D printing technology.Methods By dissecting the temporomandibular joints of 40 head and neck specimens,the bilateral structures of the temporomandibular joints were measured to obtain condyle and articular disc data.3D modeling was carried out using 3ds Max software and printed out a model of temporomandibular joint.The pathological model of the anterior disc displacement with reduction(ADDwR)was simulated by adjusting the opening degree,the position of the articular disk,and the position of the condyle of the model.Results The precise data of the right and left temporomandibular joint discs and condyle were successfully obtained by dissection and measurement.The thickness of the anterior band of left temporomandibular joint discs was(2.02±0.57)mm,the thickness of the middle band was(1.46±0.33)mm,the thickness of the posterior band was(3.00±0.46)mm,the anterior-posterior diameter was(9.60±0.72)mm,and the internal-external diameter was(17.73±0.84)mm.While the thickness of the anterior band of right temporomandibular joint discs was(1.84±0.35)mm,and the thickness of the middle band was(1.43±0.28)mm,the thickness of posterior band was(3.08±0.49)mm,the anterior-posterior diameter was(9.30±0.88)mm,and the internal-external diameter was(17.38±1.10)mm.The internal-external diameter of the left temporomandibular joint condyle was(18.97±0.41)mm,and the anterior-posterior diameter was(8.56±0.43)mm;the internal-external diameter of the right temporomandibular joint condyle was(18.86±0.75)mm,and the anterior-posterior diameter was(8.40±0.30)mm.The standard temporomandibular joint model was printed out by the measured data.The model was utilized to simulate the physiological state of temporomandibular joint under normal conditions,as well as the three pathological states of closed mouth,closed mouth to open mouth,and open mouth in the case of ADDwR.Conclusion The temporomandibular joint model can more intuitively present the changes of anatomical structure in reversible temporoman-dibular joint disorders,which is helpful for understanding and mastering the different classification of this disease.