A comparative evaluation of visual, refractive, and patient-reported outcomes of three diffractive trifocal intraocular lenses

@#OBJECTIVE: To compare the visual, refractive, and patient-reported outcomes of eyes implanted with one of 3 trifocal intraocular lenses (IOLs). METHODS: This is a cross-sectional, comparative, non-interventional study wherein subjects implanted with FineVision Micro F, AT LISA tri 839MP or AcrySof IQ PanOptix trifocal IOL after phacoemulsification were recruited. Manifest refraction, uncorrected and corrected visual acuity (VA) at distance, intermediate and near vision, contrast sensitivity, modulated transfer function (MTF) values and questionnaire answers were compared among the 3 groups using analysis of variance (ANOVA). RESULTS: Fifty-seven (57) eyes were included in the study: 21 eyes with FineVision (group A), 21 eyes with LISA tri (group B), and 15 eyes with PanOptix IOL (group C). The post-operative mean manifest spherical equivalent was -0.01D, -0.07D, and 0.05D, respectively (p=0.083). Uncorrected distance VA and best-corrected distance VA were similar among the groups. Groups A and C had better uncorrected and corrected intermediate VA at 80 cm and at 60 cm compared to group B. Group A had significantly better uncorrected near visual acuity than groups B and C (p=0.032). Mesopic contrast sensitivity testing showed group C had higher contrast sensitivities without glare in at the spatial frequency of 6 CPD (p=0.038) and with glare at 3 CPD (p=0.039) and at 12 CPD (p=0.009). MTF average height analysis showed that the group A had significantly superior resolution in far targets compared to groups B and C (p=0.001). At near targets, groups A and C had better resolutions compared to group B (p=0.017). There was no significant difference in patient satisfaction for far, intermediate and near VA among the groups. CONCLUSION: Eyes implanted with any of the 3 trifocal IOL designs achieved excellent uncorrected and bestcorrected distance, intermediate and near vision. FineVision and PanOptix provided significantly better intermediate vision than LISA tri at both 80 cm and 60 cm testing distance. FineVision had better near visual outcomes than PanOptix and LISA tri. Patient satisfaction was high in all 3 trifocal IOLS

True-false analysis reveals inherent flaws in multiple true-false tests

Background: Multiple true-false tests (MTF), a component of our assessment system, have consistently generated low scores and many failures. This was attributed to the negative marking scheme. However, no study was conducted to explore the issue further. Item analysis revealed that students omitted false options more frequently and answered them wrongly more frequently than true options. The aim of this study was to determine the performance discrepancy between true and false options of MTF tests and the reasons for such discrepancy and the poor performance of MTF in general.Methods: The student performance of past 7 years of year-3 medicine end-of-posting examinations was analysed. The item analysis reports of 23 MTF tests were used to determine the significance of the differences in omission rates, correct-answer rates and the discrimination index of true and false options.Results: There were statistically significant differences in the omission rates, correct-answer rates and discrimination index values of true and false options. This study revealed that the false options consistently let down student performance. Although negative marking could be partly blamed for the situation, no justification could be found for the use of false options to test knowledge.Conclusions: Some publications endorse MTF, but many highlight its drawbacks. The use of false options in MTF was seen as an inherent defect in this instrument. As viable alternatives like VSAQ and Constructed Response Tests are in the horizon, we conclude that MTF ought to be discarded as an assessment instrument.

Study on the Imaging Quality Evaluation of Aspheric Intraocular Lenses / 中国医疗器械杂志

The article is to study the objective evaluation method of the imaging quality of aspheric intraocular lens with different design concepts by establishing the model eye which is close to the actual corneal spherical aberration characteristics. Combined with the research data of corneal spherical aberration, the simulated cornea corresponding to Zernike c(4,0) coefficient 0.00 μm, 0.10 μm, 0.20 μm and 0.28 μm was established respectively. The optical quality of the measured simulated corneal lenses basically reached the theoretical design effect, and the deviation between the MTF value and the theoretical design value was equivalent to the MTF test repeatability. The establishment of model eye for artificial lens provides a research tool for the evaluation of aspheric intraocular lens imaging quality.

Objective Clinical Evaluation of Ocular Optical Instrument According to the Type of Lens Opacity

PURPOSE: To investigate the results using the OQAS and the Pentacam in cataract patients classified according to the type of lens opacity. METHODS: The present study included 124 eyes of 92 patients who had cataract surgery at Seoul St. Mary's Hospital from December 2011 to January 2012 and were classified into nuclear, cortical, and posterior subcapsular cataract patients. The lens opacity was determined with OSI, MTF, Strehl ratio, width 10%, width 50% and the opacity of Scheimpflug image by the OQAS and the Pentacam. Additionally, the correlation between subjective cataract classification and objective opacity value was analyzed. RESULTS: The nuclear cataract group showed a 6.40 +/- 2.41 OSI value and had high opacity. The cortical cataract group showed the highest MTF cut-off value (12.02 +/- 6.19 C/deg). When evaluating Pentacam results, the posterior subcapsular cataract group had the lowest average level of lens opacity (9.12 +/- 1.08) followed by in increasing order, the cortical cataract group (9.79 +/- 1.67) and the nuclear cataract group (11.08 +/- 1.84). The results were statistically significant (p < 0.001). The OSI value of the OQAS was significantly correlated with nuclear and posterior opacity (p = 0.049, p = 0.039, respectively) except cortical opacity (p = 0.781). MTF and nuclear opacity showed statistically significant correlation and the lens opacity of Pentacam was correlated with nuclear and posterior opacities. In cortical cataract with severe peripheral opacity, the cortical opacity showed significant correlation with Maximum. CONCLUSIONS: The OQAS and Pentacam results showed high correlation with the nuclear and posterior opacities which can be useful for cataract surgery.

Evaluation of Mean Glandular Dose and Modulation Transfer Function for Different Tube Potentials and Target-Filter Combinations in Computed Radiography Mammography

Background: Different target-filter combinations in computed radiography have different impacts on the dose and image quality in digital radiography. This study aims to evaluate the mean glandular dose (MGD) and modulation transfer function (MTF) of various target-filter combinations by investigating the signal intensities of X-ray beams. Methods: General Electric (GE) Senographe DMR Plus mammography unit was used for MGD and MTF evaluation. The measured MGD was compared with the dose reference level (DRL), whereas the MTF was evaluated using ImageJ 1.46o software. A modified Mammography Accreditation Phantom RMI 156 was exposed using different target-filter combinations of molybdenum-molybdenum (Mo-Mo), molybdenum-rhodium (Mo-Rh) and rhodium-rhodium (Rh-Rh) at two different tube voltages, 26 kV and 32 kV with 50 mAs. Results: In the MGD evaluations, all target-filters gave an MGD value of 0.05). Conclusions: Higher tube voltage and atomic number target-filter yield higher MGD values. However, the MTF is independent of the X-ray energy and the type of target-filter combinations used.

Changes in Optical Quality of Cataract Patients' Corrected Visual Acuity before and after Phacoemulsification

PURPOSE: To evaluate objectively the improvement level of a patient's visual function using the NEI-VFQ-25 questionnaire pre- and post-operatively and the OQAS results from the patient group who had the same corrected visual acuity pre- and post-operatively. METHODS: We examined and compared the NEI-VFQ-25 test, OSI, MTF cut-off, strehl ratio, OQAS, and width at 50% and 10% in 24 eyes of 24 patients who had cataract surgery between December 2011 and February 2012. The patients' corrected visual acuity in both eyes had no change (0.8 and 0.8) pre-operatively and 2 months post-operatively (1.0 and 1.0). RESULTS: The satisfaction level regarding the patients' visual function increased. The NEI-VFQ-25 test was 71.54 +/- 14.88 points pre-operatively and 85.70 +/- 6.17 points post-operatively. OSI decreased to 3.13 +/- 1.66 (OSI value) and 1.53 +/- 0.58 (OSI value), and MTF cut off value improved from 14.51 +/- 6.97 (C/deg) to 27.63 +/- 8.98 (C/deg). Strehl ratio was improved to 0.09 +/- 0.03 and 0.14 +/- 0.03, width at 50% improved to 8.44 +/- 3.73 and 4.52 +/- 1.90 and width at 10% improved to 35.30 +/- 15.22 and 18.04 +/- 8.87 pre- and post-operatively, respectively. CONCLUSIONS: The NEI-VFQ-25 test reflected the vision improvement in patients where after cataract surgery, determination of the visual function improvement only through vision would not be possible. In addition, the OQAS showed the quality of vision improved through quantified values.

Brain Activation in Response to Visually Evoked Sexual Arousal in Male-to-Female Transsexuals: 3.0 Tesla Functional Magnetic Resonance Imaging

OBJECTIVE: This study used functional magnetic resonance imaging (fMRI) to contrast the differential brain activation patterns in response to visual stimulation with both male and female erotic nude pictures in male-to-female (MTF) transsexuals who underwent a sex reassignment surgery. MATERIALS AND METHODS: A total of nine healthy MTF transsexuals after a sex reassignment surgery underwent fMRI on a 3.0 Tesla MR Scanner. The brain activation patterns were induced by visual stimulation with both male and female erotic nude pictures. RESULTS: The sex hormone levels of the postoperative MTF transsexuals were in the normal range of healthy heterosexual females. The brain areas, which were activated by viewing male nude pictures when compared with viewing female nude pictures, included predominantly the cerebellum, hippocampus, putamen, anterior cingulate gyrus, head of caudate nucleus, amygdala, midbrain, thalamus, insula, and body of caudate nucleus. On the other hand, brain activation induced by viewing female nude pictures was predominantly observed in the hypothalamus and the septal area. CONCLUSION: Our findings suggest that distinct brain activation patterns associated with visual sexual arousal in postoperative MTF transsexuals reflect their sexual orientation to males.

Comparison Study of Image Quality of Direct and Indirect Conversion Digital Mammography System / 의학물리

The purpose of this study is to comprehensively compare and evaluate the characteristics of image quality for digital mammography systems which use a direct and indirect conversion detector. Three key metrics of image quality were evaluated for the direct and indirect conversion detector, the modulation transfer function (MTF), normalized noise power spectrum (NNPS), and detective quantum efficiency (DQE), which describe the resolution, noise, and signal to noise performance, respectively. DQE was calculated by using a edge phantom for MTF determination according to IEC 62220-1-2 regulation. The contrast to noise ratio (CNR) was evaluated according to guidelines offered by the Korean Institute for Accreditation of Medical Image (KIAMI). As a result, the higher MTF and DQE was measured with direct conversion detector compared to indirect conversion detector all over spatial frequency. When the average glandular dose (AGD) was the same, direct conversion detector showed higher CNR value. The direct conversion detector which has higher DQE value all over spatial frequency would provide the potential benefits for both improved image quality and lower patient dose in digital mammography system.

Signal and Noise Analysis of Indirect-Conversion Digital Radiography Detectors Using Linear-systems Transfer Theory / 의학물리

For the use of Indirect-conversion CMOS (complementary metal-oxide-semiconductor) detectors for digital x-ray radiography and their better designs, we have theoretically evaluated the spatial-frequency-dependent detective quantum efficiency (DQE) using the cascaded linear-systems transfer theory. In order to validate the developed model, the DQE was experimentally determined by the measured modulation-transfer function (MTF) and noise-power spectrum, and the estimated incident x-ray fluence under the mammography beam quality of W/Al. From the comparison between the theoretical and experimental DQEs, the overall tendencies were well agreed. Based on the developed model, we have investigated the DQEs values with respect to various design parameters of the CMOS x-ray detector such as phosphor quantum efficiency, Swank noise, photodiode quantum efficiency and the MTF of various scintillator screens. This theoretical approach is very useful tool for the understanding of the developed imaging systems as well as helpful for the better design or optimization for new development.

Imaging Characteristics of Computed Radiography Systems / 의학물리

With recent advancement of the medical imaging systems and picture archiving and communication system (PACS), installation of digital radiography has been accelerated over past few years. Moreover, Computed Radiography (CR) which was well established for the foundation of digital x-ray imaging systems at low cost was widely used for clinical applications. This study analyzes imaging characteristics for two systems with different pixel sizes through the Modulation Transfer Function (MTF), Noise Power Spectrum (NPS) and Detective Quantum Efficiency (DQE). In addition, influence of radiation dose to the imaging characteristics was also measured by quantitative assessment. A standard beam quality RQA5 based on an international electro-technical commission (IEC) standard was used to perform the x-ray imaging studies. For the results, the spatial resolution based on MTF at 10% for Agfa CR system with I.P size of 8x10 inches and 14x17 inches was measured as 3.9 cycles/mm and 2.8 cycles/mm, respectively. The spatial resolution based on MTF at 10% for Fuji CR system with I.P size of 8X10 inches and 14x17 inches was measured as 3.4 cycles/mm and 3.2 cycles/mm, respectively. There was difference in the spatial resolution for 14x17 inches, although radiation dose does not effect to the MTF. The NPS of the Agfa CR system shows similar results for different pixel size between 100 micrometer for 8x10 inch I.P and 150 micrometer for 14x17 inch I.P. For both systems, the results show better NPS for increased radiation dose due to increasing number of photons. DQE of the Agfa CR system for 8X10 inch I.P and 14x17 inch I.P resulted in 11% and 8.8% at 1.5 cycles/mm, respectively. Both systems show that the higher level of radiation dose would lead to the worse DQE efficiency. Measuring DQE for multiple factors of imaging characteristics plays very important role in determining efficiency of equipment and reducing radiation dose for the patients. In conclusion, the results of this study could be used as a baseline to optimize imaging systems and their imaging characteristics by measuring MTF, NPS, and DQE for different level of radiation dose.

MTF Evaluation and Clinical Application according to the Characteristic Kernels in the Computed Tomography / 의학물리

Our objective was to evaluate the clinical feasibility of spatial domain filtering as an alternative to additional image reconstruction using different kernels in CT. Kernels were grouped as H30 (head medium smooth), B30 (body medium smooth), S80 (special) and U95 (ultra sharp). Derived from thin collimated source images, four sets of images were generated using phantom kernels. MTF (50%, 10%, 2%) measured with H30 (3.25, 5.68, 7.45 lp/cm), B30 (3.84, 6.25, 7.72 lp/cm), S80 (4.69, 9.49, 12.34 lp/cm), and U95 (14.19, 20.31, 24.67 lp/cm). Spatial resolution for the U95 kernel (0.6 mm) was 33.3% greater than that of the H30 and B30 (0.8 mm) kernels. Initially scanned kernels images were rated for subjective image quality, using a five-point scale. Image scanned with a convolution kernel led to an increase in noise (U95), whereas the results for CT attenuation coefficient were comparable. CT images increase the diagnostic accuracy in head (H30), abdomen (B30), temporal bone and lung (U95) kernels may be controlled by adjusting CT various algorithms, which should be adjusted to take into account the kernels of the CT undergoing the examination.

Construction and Performance Evaluation of Digital Radiographic System / 의학물리

Current digital radiography systems are rapidly growing in clinical applications. The purpose of this study was to evaluate the characteristics of a mobile digital radiographic system. The performance of the mobile DR system was evaluated by measuring the modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE). Measurements were made on a LISTEM Mobix-1000 generator and a Teleoptic PRA Alpha-R4000 detector. Imaging characteristics were measured for these two systems using the IEC-61267 defined RQA5 (kVp: 74, additional filtration: 21 mmAl) radiographic condition. The MTF at 10% was measured as 2.4 cycles/mm and the DQE(0) values for radiation exposure 0.19, 0.5, and 1.3 mR were measured as 54%, 55%, and 76%, respectively. The NPS curves gradually decreased at high spatial frequencies. This high DQE at low frequencies, may be useful for low frequency information. The results suggested that mobile DR system could be integrated with emergency ambulance system in teleradiologic imaging applications.

Characteristics of a new cone beam computed tomography / 대한구강악안면방사선학회지

PURPOSE: To determine the physical properties of a newly developed cone beam computed tomography (CBCT). MATERIALS AND METHODS: We measured and compared the imaging properties for the indirect-type flat panel detector (FPD) of a new CBCT and the single detector array (SDA) of conventional helical CT (CHCT). RESULTS: First, the modulation transfer function (MTF) of the CBCT were superior to those of the CHCT. Second, the noise power spectrum (NPS) of the CBCT were worse than those of the CHCT. Third, detective quantum efficiency (DQE) of the indirect-type CBCT were worse than those of the CHCT at lower spatial frequencies, but were better at higher spatial frequencies. Although the comparison of contrast-to-noise ratio (CNR) was estimated in the limited range of tube current, CNR of CBCT were worse than those of CHCT. CONCLUSION: This study shows that the indirect-type FPD system may be useful as a CBCT detector because of high resolution.

Effect of injectable Xuebijing on proliferation of murine brain microvascular endothelial cell line bEnd.3 / 中华急诊医学杂志

Objective To investigate the effect of injectable Xuebijing on the proliferation of mouse brain microvascular endothelial cell in vitro.Methods Cultured mouse brain microvascular endothelM cell line bEnd. 3 was treated by injectable Xuebijing of different concentrations,0 (control),5,25 and 50 mg/ml.The regulatory. effect of Xuebijing on the proliferation of cell line bEnd.3 was observed and studied by means of MTT method and cell cycle analyzed with flow cytometry.Results Compared to the control group,MTT and proliferation index (PI) of 5 and 25 mg/ml groups were significantly increased at 12 and 24 h,and PI,but not MTT,of these 2 groups was decreased remarkably at 48 h.Meanwhile,50 mg/ml group showed significantly decreased MTT at 24 and 48 h,and PI of this group was increased obviously at 12 and 24 h,but decreased significantly at 48 h. Conclusions Injectable Xuebijing at certain concentrations might promote the proliferation of cultured mouse brain microvascular endothelial,cells within specific time frame.

Research on management of medical equipment / 医疗卫生装备

As a part of modern medical practice,medical treatment facility(MTF) has playing an important role in disease diagnosis and medical treatment;therefore,nowadays more attention is paid to the medical equipment management.The methods of equipment management which combine actuality and practical experience are introduced in order to make the management of medical equipment more scientific and effective.

Supervision on Measurement of Quality and Safety on Medical Treatment Facility / 医疗卫生装备

To combine "the rule of military medical measurement" with the current situation of medical treatment quality control, the foundation, important component and necessary condition of medical treatment quality control was described. Some idiographic advices of intercoordination and communication in medical measurement institution, the direction and training of special technique, and how to develop compulsion coerciveness checking in base course were given. These are valuable for insuring medical treatment facility in hospital.

The Effects of Gantry Rotation Time on Image Quality in 64-slice Spiral CT / 实用放射学杂志

Objective To study the effects of gantry rotation time on image quality in 64-slice spiral CT. Methods Using the same CT technique and body mode as those used for 64-slice spiral CT, delta phantom was firstly layed on the isocenter, then scanned and reconstructed with SOMATOM Sensation 64-slice spiral CT. Slice sensitivity profile(SSP) was measured from which modulation transfer function (MTF) were got by Fourier transfer. The Catphan500 phantom was layed on the table, then scanned and reconstructed with SOMATOM Sensation 64-slice spiral CT. The maximum linepair and minimum size of the targets visualized. Results The MTF curve was nearly overlapped on 0.5 s and 1.0 s gantry rotation time, the values of 5% MTF were 11.3 LP/cm and 11.9 LP/cm. Their spatial resolution and low contrast resolution were completely identical.Conclusion The image quality is no distinction on 0.5 s group and 1.0 s group of gantry rotation time. In order to shorten the scan time and eliminate the breath defect, we suggest that the 0.5 s gantry rotation time be used routinely at body spiral scan mode.