Agreement and repeatability of Icare ic100 tonometer

Purpose:To find the agreement and repeatability of Icare ic100 tonometer.Methods:We included 150 subjects above the age of 18 years for this cross-sectional, multicenter study with intraocular pressure (IOP) ≥7 mmHg. After the initial ophthalmic examination, two masked examiners took five IOP measurements using three different instruments; Icare ic100, Icare TA01i, and Goldmann applanation tonometer (GAT) in only one eye of the participants. Comparison of agreement of IOP using different instruments was quantified with intraclass correlation coefficient (ICC) using the two-way random effects models of absolute agreement and Cronbach''s alpha. The test-retest variability of the instruments was assessed by deriving repeatability coefficient (RC) and coefficient of variation (CV).Results:Agreement between the tonometers across the different IOP groups had no statistically significant difference in their mean IOP. Icare ic100 was found to have good reliability across all IOP groups (ICC value >0.78) when compared with Icare TA01i. In comparison with GAT, Icare ic100 showed good reliability across all IOP groups (ICC >0.87) except >16 to <23 mmHg group where it showed moderate reliability (ICC = 0.52). Icare ic100 showed good repeatability with RC and CV of 2.67 and 4.89, respectively.Conclusion:Icare ic100 rebound tonometer can measure IOP with relatively small measurement error and can provide a reliable and repeatable reading in comparison with GAT across a wide pressure range without hampering corneal health.     

Test–retest repeatability of [18F]Flortaucipir PET in Alzheimer’s disease and cognitively normal individuals

The aim of this study was to investigate the test–retest (TRT) repeatability of various parametric quantification methods for [¹⁸F]Flortaucipir positron emission tomography (PET). We included eight subjects with dementia or mild cognitive impairment due to Alzheimer’s disease and six cognitively normal subjects. All underwent two 130-min dynamic [¹⁸F]Flortaucipir PET scans within 3 ± 1 weeks. Data were analyzed using reference region models receptor parametric mapping (RPM), simplified reference tissue method 2 (SRTM2) and reference logan (RLogan), as well as standardized uptake value ratios (SUVr, time intervals 40–60, 80–100 and 110–130 min post-injection) with cerebellar gray matter as reference region. We obtained distribution volume ratio or SUVr, first for all brain regions and then in three tau-specific regions-of-interest (ROIs). TRT repeatability (%) was defined as |retest–test|/(average (test + retest)) × 100. For all methods and across ROIs, TRT repeatability ranged from (median (IQR)) 0.84% (0.68–2.15) to 6.84% (2.99–11.50). TRT repeatability was good for all reference methods used, although semi-quantitative models (i.e. SUVr) performed marginally worse than quantitative models, for instance TRT repeatability of RPM: 1.98% (0.78–3.58) vs. SUVr_80–100: 3.05% (1.28–5.52), p < 0.001. Furthermore, for SUVr_80–100 and SUVr_110–130, with higher average SUVr, more variation was observed. In conclusion, while TRT repeatability was good for all models used, quantitative methods performed slightly better than semi-quantitative methods.     

咀嚼肌表面电极肌电图重复性检验和参考值的建立

目的:对成年人咀嚼肌表面电极采集的肌电信号加以分析,研究下颌在6种不同运动状态下咀嚼肌肌电信号的可重复性,并取得正常参考值。方法:30名22-44岁受试者进行咀嚼肌表面电极肌电图检查,记录下颌姿势位、牙尖交错位和扣齿运动时双侧咬肌、颞肌前束和二腹肌前腹的肌电活动,每个受试者在3个不同时段各测试一次。结果:3次测试的咀嚼肌峰值电位之间无统计学差异(P>0.05)。下颌姿势位时,右侧咬肌峰值电位95%正常参考值为0-0.1,左侧为0-0.13,右侧颞肌前束为0-0.67,左侧颞肌前束为0-0.1,右侧二腹肌前腹为0-0.13,左侧二腹肌前腹为0-0.1;牙尖交错位时,右侧咬肌峰值电位95%正常参考值为0.33-2.53,左侧为0.47-2.5,右侧颞肌前束为0.23-2.23,左侧颞肌前束为0.2-3.67,右侧二腹肌前腹为0.13-1.07,左侧二腹肌前腹为0.1-0.87;扣齿运动时右侧咬肌峰值电位95%正常参考值为0.5-2.5,左侧为0.73-2.3,右侧颞肌前束为0.4-3.47,左侧颞肌前束为0.3-3.63,右侧二腹肌前腹为0.2-1.07,左侧二腹肌前腹为0.13-0.97。结论:表面电极采集的双侧咬肌、颞肌前束和二腹肌前腹的肌电活动具有一定的可重复性。     

慢性症状性骨质疏松性胸腰椎骨折的影像学分型及其信度检验

[目的]针对慢性症状性骨质疏松性胸腰椎骨折(chronic symptomatic osteoporotic thoracolumbar fracture,CSOTF),本研究提出了一种全新的基于骨折影像学特点的分型体系,并对其可信度进行了检验。[方法]回顾性分析2010年1月~2017年6月本院收治的368例具有完整影像资料的CSOFT患者,影像学检查包括腰椎正侧位及过屈过伸位X线片、CT和MRI。根据影像学上伤椎是否存在失稳、椎管是否合并狭窄和有无后凸畸形三个关键特征,将CSOTF分为I型(动态稳定型)、II型(动态不稳型)、III型(椎管狭窄型)、IV型(后凸畸形型),V型(混合型)。随机抽取40例患者,由10名医生按照上述分型体系对患者进行分型评估,并在初次评估1个月后再进行第二次评估,计算测量者间信度(interobserver reliability)与测量者内信度(intraobserver reliability)。[结果]在368例CSOTF患者中,I型最多,占55.71%;V型最少,占5.99%。对40例CSOTF患者的分型评估,测量者间可信度的总体κ值为0.834,表明CSOTF影像学分型一致性好;测量者内可信度的总体κ值为0.853,表明两轮评估的重复性好。[结论]本研究表明CSOFT影像学分型,分类简单,一致性与重复性好,有利于临床评估与信息沟通。     

Phase contrast MRI quantification of pulsatile volumes of brain arteries, veins, and cerebrospinal fluids compartments: repeatability and physiological interactions

Purpose:

To study measurement repeatability and physiological determinants on measurement stability for phase contrast MRI (PC‐MRI) measurements of cyclic volume changes (ΔV) of brain arteries, veins, and cerebrospinal fluid (CSF) compartments.

Materials and Methods:

Total cerebral blood flow (tCBF), total internal jugular flow (tJBF) and spinal CSF flow at C2–C3 level and CSF in the aqueduct was measured using five repetitions in 20 healthy subjects. After subtracting net flow, waveforms were integrated to calculate ΔV of arterial, venous, and cerebrospinal fluid compartments. The intraclass correlation coefficient (ICC) was used to measure repeatability. Systematic errors were investigated by a series of phantom measurements.

Results:

For ΔV calculated from tCBF, tJBF and both CSF waveforms, the ICC was ≥0.85. ΔV from the tCBF waveform decreased linearly between repetitions (P = 0.012). Summed CSF and venous volume being shifted out from the cranium was correlated with ΔV calculated from the tCBF waveform (r = 0.75; P < 0.001). Systematic errors increased at resolutions <4 pixels per diameter.

Conclusion:

Repeatability of ΔV calculated from tCBF, tJBF, and CSF waveforms allows useful interpretations. The subject's time in the MR system and imaging resolution should be considered when interpreting volume changes. Summed CSF and venous volume changes was associated with arterial volume changes. J. Magn. Reson. Imaging 2012;35:1055‐1062. © 2011 Wiley Periodicals, Inc.     

Visual assessment of intra ventricular flow from colour M-mode Doppler images

Left intra ventricular filling was studied by colour M-mode Doppler ultrasound to determine whether the flow pattern can be assessed visually, and explore its relation to left ventricular (LV) function. Patients with coronary artery disease (CAD) or dilated cardiomyopathy (DCM) were divided into three groups according to angiographically evaluated LV function. The groups were compared with a control group of 54 healthy volunteers. The mitral to apical delay of early diastolic flow was qualitatively assessed from printed colour M-mode images, twice by four independent observers blinded to the subject's status. The repeatability of the assessments as determined by the kappa statistic was good intra observer (k=0.75) and moderate inter observer (k=0.53). The CAD-group with angiographically normal LV function (n=25) had flow patterns resembling those observed in the control group. The group with ejection fraction (EF) <50% (n=19) had flow patterns clearly different from the control group. Patients with regional wall motion abnormality (RWMA) but EF >50% (n=16) exhibited flow patterns intermediate between the control and the low EF group. Among the 50 CAD patients there was a negative correlation between EF and the presence of delay of apical peak velocity (Spearman's r _s =–0.62, p < 0.0001). A visible delay of apical peak velocity had a sensitivity towards DCM of 83% and specificity of 75%. The sensitivity towards CAD with either RWMA or low EF was 55% and the specificity 75%. In conclusion, visual assessment of intra ventricular flow patterns was feasible and allowed discrimination between normal and diseased ventricles.Abbreviations CAD coronary artery disease - DCM dilated cardiomyopathy - EF ejection fraction - LV left ventricle/left ventricular - LVEDP left ventricular end diastolic pressure - RWMA regional wall motion abnormality Marie Stugaard and Torkel Steen were recipients of fellowships from the Norwegian Council on Cardiovascular Diseases during the study.