Standard Reference Plane Research Articles

Depth Measurement Error Analysis and Structural Parameter Correction of Structured Light Depth Imager

Considering that structured light depth imagers are difficult to use for precision measurements due to their limited measurement accuracy, we propose an innovative method for correcting structural parameters of structured light depth imagers to reduce the depth measurement error caused by structural parameter errors. For the structured light depth imager, the analytical imaging model is established, and the model of depth error caused by structural parameter errors is established based on the analysis of the depth measurement error analysis. Then, structural parameters are corrected according to the depth measurement error analysis and processing based on experimental depth imaging data of the standard reference plane at the maximum depth. As a result, the corrected analytical imaging model and corrected depth measurement values are obtained. Experimental results have demonstrated the success of this proposed method and its simplicity and convenience.

Use of real-time artificial intelligence in detection of abnormal image patterns in standard sonographic reference planes in screening for fetal intracranial malformations.

To develop and validate an artificial intelligence system, the Prenatal ultrasound diagnosis Artificial Intelligence Conduct System (PAICS), to detect different patterns of fetal intracranial abnormality in standard sonographic reference planes for screening for congenital central nervous system (CNS) malformations. Neurosonographic images from normal fetuses and fetuses with CNS malformations at 18-40 gestational weeks were retrieved from the databases of two tertiary hospitals in China and assigned randomly (ratio, 8:1:1) to training, fine-tuning and internal validation datasets to develop and evaluate the PAICS. The system was built based on a real-time convolutional neural network (CNN) algorithm, You Only Look Once, version 3 (YOLOv3). An image dataset from a third tertiary hospital was used to further validate, externally, the performance of the PAICS and to compare its performance with that of sonologists with different levels of expertise. Furthermore, a prospective video dataset was employed to evaluate the performance of the PAICS in a real-time scan scenario. The diagnostic accuracy, sensitivity, specificity and area under the receiver-operating-characteristics curve (AUC) were calculated to assess the performance of the PAICS and to compare this with the performance of sonologists with different levels of experience. In total, 43 890 images from 16 297 pregnancies and 169 videos from 166 pregnancies were used to develop and validate the PAICS. The system achieved excellent performance in identifying 10 types of intracranial image pattern, with macro- and microaverage AUCs, respectively, of 0.933 (95% CI, 0.798-1.000) and 0.977 (95% CI, 0.970-0.985) for the internal validation image dataset, 0.902 (95% CI, 0.816-0.989) and 0.898 (95% CI, 0.885-0.911) for the external validation image dataset and 0.969 (95% CI, 0.886-1.000) and 0.981 (95% CI, 0.974-0.988) in the real-time scan setting. The performance of the PAICS was comparable to that of expert sonologists in terms of macro- and microaverage accuracy (P = 0.863 and P = 0.775, respectively), sensitivity (P = 0.883, P = 0.846) and AUC (P = 0.891, P = 0.788), but required significantly less time (0.025 s per image for PAICS vs 4.4 s for experts, P < 0.001). Both in the image dataset and in the real-time scan setting, the PAICS achieved excellent diagnostic performance for various fetal CNS abnormalities. Its performance was comparable to that of experts, but it required less time. A CNN algorithm can be trained to detect fetal CNS abnormalities. The PAICS has the potential to be an effective and efficient tool in screening for fetal CNS malformations in clinical practice. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Correlation of transverse mandibular dimension with naso-pharyngeal and oro-pharyngeal airway using computed tomographic analysis – A retrospective observational study

Purpose: The aim of the study was to investigate changes in the naso-pharyngeal and oro-pharyngeal airway with varying degrees of mandibular flare. Methods: The investigators implemented a retrospective, observational study including CT data from patients fitting the inclusion criteria. Linear and angular measurements were used to assess the flare and transverse dimension of the mandible, while standard reference planes were used for assessment of airway dimensions. The primary outcome measures were to correlate and quantify the naso-pharyngeal and oro-pharyngeal volumes with mandibular flare. Secondary outcome measures were to study the intra-variable correlation. Significance level was fixed at 5% (α = 0.05). Results: The sample included CT data from 30 individuals with apparently normal craniofacial skeleton (53% males and 46.7% female with a mean age of 29.53 years). Both nasopharyngeal and oropharyngeal volumes demonstrated moderate positive correlations with inter-condylar width (p = 0.020 and p = 0.038) and inter-condylar angles (p = 0.041 and p = 0.005) respectively. Linear regression modelling demonstrated that for every millimetre increase of the Inter-condylar width, the naso-pharyngeal and oro-pharyngeal airway volume increased by 0.423 cm3 (p = 0.020) and 0.381 cm3 (p = 0.038) respectively, and every degree increase of inter-condylar angle produced an increase the nasopharyngeal and oropharyngeal volumes by 0.376cm3 (p = 0.041) and 0.496cm3 (p = 0.005) respectively. Conclusion: Parameters of mandibular flare demonstrate statistically significant correlation to pharyngeal airway volume, which may be a relevant predictor to evaluate airway in patients undergoing corrective skeletal surgery.

The Influence of the Mandibular Chin Angle on the Occurrence of Mandibular Condylar Fracture: A Retrospective Study.

Background Condylar fractures are commonly associated with symphysis/parasymphysis fractures. Condylar fractures have been attributed to direct and indirect traumatic forces, the direction and magnitude of the forces, and the condylar anatomy. The chief aim of this study was to determine the association between the newly defined mandibular chin angle and the occurrence of condylar fractures. Materials and Methods A retrospective study was conducted to analyze two-dimensional computed tomography (2D CT) scans of patients with a history of chin trauma. The outcome was a symphysis/parasymphysis fracture with or without fracture of the mandibular condyle. The Mediff InstaRISPACS web-based platform was used to measure the chin angle. The cerebral aqueduct of Sylvius in the corresponding 2D CT midsagittal image was the standard reference plane to measure the chin angle. The SPSS Version 20 (IBM Corp, Armonk, NY) was used for data analysis. Results The sample size included 120 2D CT scans of patients with symphysis/parasymphysis fractures (60 associated with condylar fractures and 60 without condylar fractures). The mean chin angle in the group without condylar fracture was 133.35 ± 3.87°, which was approximately 15° lesser than in the condylar fracture group (mean, 148.56 ± 5.49°), and these findings were statistically significant (P < 0.05). Conclusion Individuals with a high chin angle are potentially at a higher risk of sustaining associated condylar fractures.

Three-dimensional orientation of the femoral curvature. How well does it match with the sagittal curvature of femoral implants?

BackgroundThe curvature of the femoral shaft is generally considered as residing in the sagittal plane. While many studies have measured the femur's radius of curvature, very few have studied the orientation of the plane in which it resides. The orientation of this plane may affect the rotation of intramedullary nails or revision stems with diaphyseal locking. This led us to conduct a three-dimensional (3D) anatomical study to: 1) analyze the 3D curvature of the femoral diaphysis by specifying the orientation of the plane in which it resides, 2) look for relationships between the curvature's orientation and anatomical parameters of the femur. HypothesisWe hypothesized that the femoral curvature resides in the anterolateral plane, not the sagittal plane. Materials and methodsA computed tomography scan was performed on 45 dry femur bones provided by a cadaver laboratory. The 3D reconstructions were analyzed to characterize the curvature of the diaphyseal shaft, radius of its various portions and to determine the plane in which it resides relative to the standard coronal reference plane defined by three points: posterior side of both condyles and the greater trochanter. The following parameters were measured: length, neck-shaft angle, femoral valgus (between anatomical and mechanical axis) and neck anteversion. ResultsThe largest curvature was in a plane oriented on average of 78.3°±14.9° (35.2° to 106.7°) anterolateral. The correlation between femoral curvature and neck-shaft angle (R=0.172), size (R=0.095), valgus (R=0.104) and overall curvature (R=0.60) was low. DiscussionImplants with diaphyseal fixation are designed such that the femoral curvature resides in a strict sagittal plane. Long revision stems with diaphyseal fixation may have a tendency to rotate laterally (externally) during insertion. Correcting this external rotation to prevent anteversion may result in a less than satisfactory press-fit. The femoral curvature must be taken into account when designing intramedullary implants. Level of evidenceIV, Cadaver study without control group.

Speeding Up of Nondestructive Inspection for Shape-Distorted Billet by Simultaneous Measurement of Time of Flight

We have proposed a nondestructive inspection method for steel billets using ultrasonic computerized tomography by time of flight (TOF). It has been found that the proposed method may detect defects inside high-attenuation materials with the aid of sequential pulse transmission all around the surface. However, it takes a long time to measure the TOF by this method owing to large numbers of scans and transmissions. In this paper, we propose a TOF measurement method to apply our inspection method to simultaneous TOF measurement in a shape-distorted billet to speed up the inspection. In this method, besides a measurement plane and a reference plane, a standard reference plane is used to compensate not only the effect of the characteristics between a transmitter and a receiver but also the effect of the shape distortion in simultaneous measurement. In this paper, the performance of the present method was verified by numerical simulation and experiment. As a result, the defects in a shape-distorted billet were successfully visualized in simultaneous TOF measurement by the present method. Moreover, it was confirmed that the proposed method diminished the artifacts in the computerized tomography (CT) images by compensating the error caused by multiple simultaneous transmissions. It was revealed that the present method is more robust to noise than the previous method. Therefore, it is expected that the TOF measurement in the nondestructive inspection of a shape-distorted billet can be sped up by the proposed method.

Comparison of Neuroretinal Rim Area Measurements Made by the Heidelberg Retina Tomograph I and the Heidelberg Retina Tomograph II

Purpose:To investigate the agreement between neuroretinal rim area (RA) measurements using the Heidelberg Retina Tomograph I (HRT Classic) and Heidelberg Retina Tomograph II (HRT II). To compare apparent RA changes in follow-up series of HRT II topographies when using either an HRT Classic or HRT II mean topography as baseline.Design:Cross-sectional study and “no-change,” short time series study.Participants:Forty-three ocular hypertensive and 31 primary open angle glaucoma subjects.Methods:Five HRT Classic and 5 HRT II examinations were acquired from 1 eye of each subject, across 2 visits within 6 weeks. For the cross-sectional study, follow-up RA measurements from HRT Classic and HRT II were compared, using the same HRT Classic mean topography as the baseline. The linear rates of RA change were compared in 2 short time series with either an HRT Classic or an HRT II mean topography as baseline, and 4 follow-up HRT II mean topographies. Intervals between topographies were arbitrarily set at 1 year for meaningful comparisons of rates. Rates of RA change over time were calculated by linear regression. Separate analyses were performed using 3 available reference planes (RP).Main Outcome Measures:Global and sectoral RA measurements in HRT Classic and HRT II mean topographies; linear rates of RA change.Results:HRT Classic minus HRT II mean differences (95% limits of agreement) were 0.09 (−0.17, 0.35) mm2, 0.09 (−0.13, 0.32) mm2, and 0.11 (−0.24, 0.46) mm2 for the Moorfields, 320 µm, and standard RPs, respectively (P<0.001 for all RPs, Wilcoxon rank sum test). In the time series, the mean differences (95% limits of agreement) of RA rates of change (HRT Classic baseline minus HRT II baseline) were −0.01 (−0.06, 0.03) mm2/y, −0.01 (−0.06, 0.04) mm2/y, and −0.02 (−0.09, 0.05) mm2/y using the Moorfields, 320 µm, and standard RPs, respectively.Conclusion:Although HRT software is backward-compatible, follow-up RA measurements made in the same eye using HRT Classic and HRT II devices display statistically and clinically meaningful systematic differences when HRT Classic topographies are used as a baseline.

공동주택 안목치수 설계기준에 의한 붙박이장의 표준화방안 연구

Built-in wardrobe is constructing after ordering and making, because built-in wardrobe's size is fixed as housing measurement. It is hard to speak built-in wardrobe components of construction in these ways, and application of an MC (Modular Coordination) design system is meaningless too. And above all, measurement before construction isn't to expect standardization, and to increase custom-made furniture. So I suggest the standardization of built-in wardrobe utilizing standard last finish and reference plane in order to prevent an evil influence of built-in wardrobe's construction. And we utilized a reference plane, and we present construction document and design plan in order to solve these problems. The first stage, we investigate manufacture of a preferential domestic system kitchen and construction state, and we derive from a problem in viewpoints of standardization for this. And we analyze an effect got by application of the assembly basis aspect that we presented, and we can raise efficiency of standardization of housing and construction industry, and we light ultimately up. I will apply a standardization plan as above, and define that this assures a standardization of components and an economic effect.

HRT-3 Moorfields reference plane: effect on rim area repeatability and identification of progression

Aims:To assess the effect of the Moorfields Reference Plane on Heidelberg Retina Tomograph (HRT) rim area repeatability and its effect on progression rates using an event analysis.Methods:The HRT reference plane...

Analysis of HRT Images: Comparison of Reference Planes

The values of Heidelberg Retinal Tomograph (HRT; Heidelberg Engineering, Heidelberg, Germany) stereometric parameters depend on the reference plane (RP), the instability of which results in parameter variability. Identification of change depends on RP stability. This study was undertaken to evaluate the influence of various RPs on rim areas (RAs) in a longitudinal image series. A longitudinal image series of 31 subjects with ocular hypertension who had reproducible visual field loss and 19 normal subjects was analyzed using five different RPs: the standard RP (HRT software version 3.1.2.0), two 320-mum RPs (software ver. 3.1.2.0 and 1.7.0), a previously described experimental RP, and a new Moorfields RP. The Moorfields RP takes the standard RP at baseline and then is fixed relative to the reference ring for subsequent images. Linear regression of RA over time was performed, and the slope and residual SD (RSD) were calculated for each RP. Comparisons between RPs were made by paired t-tests. In eyes with progressing disease, application of the standard RP resulted in significantly greater variability (as measured by the RSD) compared with other RPs (mean 0.057 mm(2) vs. 0.035-0.038 mm(2)). There was a trend toward faster RA change/time (mean, -0.0123 mm(2)/y) for the standard RP and slower (-0.0095 mm(2)/y) for the experimental RP. There was a trend for the Moorfields RP to result in the best signal-to-noise ratio (speed of RA change/variability): mean RA slope -0.0118 mm(2)/y and mean global RSD 0.037mm(2). Compared to the standard RP, the Moorfields RP has significantly lower variability and probably provides a greater facility for discriminating RA change from measurement variability in a longitudinal HRT image series.

Improving Glaucoma Diagnosis by the Combination of Perimetry and HRT Measurements

The aim of this study was to determine, whether the combination of morphologic data of the optic nerve head and visual field (VF) data would improve diagnosis of glaucoma, on the basis of the measurements alone. Eighty-eight perimetric glaucomatous and 88 normal optic discs from the Erlangen Glaucoma Registry were matched for age. All normals and patients were examined in a standardized manner (Slitlamp biomicroscopy, gonioscopy, 24 h-applanation tonometry, automated VF testing, 15-degree optic disc stereographs, and Heidelberg Retina Tomograph (HRT)-scanning of the optic disc). The HRT variables were calculated in 4 optic disc sectors. All variables were calculated with the software's standard reference plane. To gain the same allocation of sectors as provided by the HRT software, the VF responses were averaged within 4 sectors. Classification results of these VF responses were compared with the summarized results within 4 sectors. Six different combinations of morphologic and VF data were used to assess their suitability to diagnose the disease. HRT measurements, and the standard output of the Octopus (HRT/PERI1), HRT measurements and the summarized sectors and their standard deviations (HRT/PERI2), HRT measurements, standard output of the octopus and the summarized sectors and their standard deviations (HRT/PERI1/PERI2), standard output of the Octopus (PERI1), summarized sectors of the Octopus and their standard deviations (PERI2) and HRT measurements. To assess the diagnostic value of the different data sets machine learning classifiers, stabilized linear discriminant analysis, classification trees, bagging, and double-bagging were applied. Combination of morphologic and VF data improved the automated classification rules. The accuracy to diagnose glaucoma just by VF and HRT indices was maximized for double-bagging using both diagnostic tools. An estimated misclassification probability of less than 0.07 could be achieved for the primary open angle glaucoma patients combining HRT and VF sectors by double bagging. So highest sensitivity was 95% and specificity 91%, achieved by double-bagging and combination of HRT, PERI1, and PERI2. The combination of optic disc measurements and VF data could not only improve glaucoma diagnosis in future, but could also help to find an objective way to diagnose glaucomatous optic atrophy. The limitation of the topographic relationship between structure and function is the individual variability of the optic disc morphology and the subjective variability of VF testing.

The effect of the menstrual cycle on optic nerve head analysis in healthy women

To determine the effect of the menstrual cycle on optic nerve head topographic analysis in normally menstruating, healthy women. The study included single eyes selected randomly from each of 52 healthy women with regular menstrual cycles. All subjects underwent a complete ocular examination. Optic nerve head topographic analyses were performed using a confocal scanning laser ophthalmoscope, the Heidelberg Retinal Tomograph II (HRT II, software version 1.6). The analyses were repeated three times during the menstrual cycle: in the follicular phase (days 7-10 of the cycle), at ovulation, and in the late luteal phase (days 1-3 before menstrual bleeding). Serum oestradiol, progesterone and luteinizing hormone levels were measured at each menstrual phase. Fourteen subjects were excluded from the study. The mean age of the subjects (n = 38) was 25.6 +/- 3.7 years (range 21-34 years). Blood oestradiol levels were significantly lower in the late luteal phase (35.8 pg/ml) (p < 0.0001). The mean disc area of the subjects was 1.94 +/- 0.33 mm(2). The neuroretinal rim area decreased significantly during the luteal phase (p < 0.001). However, the linear cup : disc ratio, cup : disc area ratio and the cup area were significantly higher during the luteal phase (p < 0.001). These observations raise the possibility that sex hormone fluctuations which occur during a normal menstrual cycle in healthy women significantly alter neuroretinal rim area and cup variables of the optic nerve head. These findings should be taken into consideration in the clinical follow-up of young women with glaucoma.

Validity of Rim Area Measurements by Different Reference Planes

Reference plane description of the neuroretinal rim in scanning laser tomography should correctly represent optic nerve morphology. We evaluated how well rim area analysis by different reference planes agreed with the appearance of rim area in disc images. Three expert observers subjectively and repeatedly analyzed rim area in Heidelberg Retina Tomograph (HRT) images so that each optic disc was measured six times in 100 eyes, 50 normal and 50 glaucoma. Rim area was evaluated globally and in 30 degree sectors. Agreement between rim appearance, as subjectively analyzed, and objective analysis by an experimental reference plane, the standard reference plane, and a reference plane fixed 320 microm below the reference ring was assessed in HRT images. Subjective analysis of rim area in HRT images was consistent between expert observers. Their analysis of rim appearance agreed more closely with experimental reference plane analysis than analysis by the standard or 320-microm reference planes; this was true globally and in every region of the nerve (P = 0.000). The experimental reference plane yielded higher estimates of rim area than did the standard or 320-microm reference planes. There was closer correspondence between the appearance of the neuroretinal rim in images and description by the experimental reference plane compared with description by the standard and 320-microm reference planes.

Conflict definitions and mistakes in American industrial robotics standard for static performance evaluation

The ANSI/RIA R15.05‐1‐1990 is an American national industrial robotics standard that covers methods for evaluating the point‐to‐point and static performance of industrial robots. This standard introduces many important concepts for carrying out performance tests. These concepts include standard test plane, standard test path, and working space center point. Eight mistakes and two conflict definitions related to working space center point have been identified and corrected in this paper. Most of the mistakes are definition mistakes related to the base coordinate system, working space center point, standard reference plane, and standard test plane. Mistakes also result from the confusion between the reference plane and the test plane.

Thinning of the Papillomacular Bundle in the Glaucomatous Eye and its Influence on the Reference Plane of the Heidelberg Retinal Tomography

To measure the thickness of the papillomacular bundle in glaucomatous eyes with good visual acuity and to evaluate the influence of an adjusted reference plane on the Heidelberg retinal tomography result. The thickness of the papillomacular bundle was measured with optical coherence tomography in both eyes of eight patients with asymmetric glaucoma. The eye with less glaucomatous damage with normal visual field served as the control. The difference in the thickness of the papillomacular bundle between the control eye and the glaucomatous eye was used to correct the reference plane of Heidelberg retinal tomography. The thickness of the papillomacular bundle in glaucomatous eyes was reduced (P = 0.00037) and was 33.9 +/- 16.5 microm thinner than control eyes. A corrected reference plane in Heidelberg retinal tomography caused an increased classification value (-0.683 +/- 0.164), implying that more glaucoma damage was detected after the correction. In one case the value was shifted from normal to glaucomatous after an adjustment of the reference plane. The thickness of the papillomacular bundle is decreased in glaucomatous eyes, though these eyes have good visual acuity. Evaluation of glaucoma with Heidelberg retinal tomography using the standard reference plane may underestimate the glaucoma damage.

Large optic nerve heads: megalopapilla or megalodiscs.

To evaluate megalopapillas in order to determine whether they constitute a different population, according to their specific features. Evaluation of the optic nerve head of 405 eyes divided into 172 normal eyes, 168 pre-perimetric glaucomas (phase 3 or 4), 30 primary congenital glaucomas (children with pure congenital glaucomas operated more than once and diagnosed within the first year of age), and 35 megalopapillas. The examinations were performed with the HRT (Heidelberg Retina Tomograph), using a wavelength of 680 nm and the new standard reference plane. Each examination results from the mean of 3 image acquisitions with a SD lower than n = 20. Each optic nerve head was studied in 360 degrees (segments), as well as in quadrants and octants separately (predefined segments). The visual fields were assessed with either the Octopus 1-2-3 or the Octopus 101, programs G2 and G2x (three complete phases). The intraocular pressure was measured by means of daily pressure curves including 7 measurements with applanation tonometry at the office and the first one at 6/7 a.m. with the patient still in bed. Gonioscopic examinations were also performed for classification purposes. By comparing all the stereometric parameters with the Total Area (disc area) and the Rim Volume it has been concluded that the megalopapilla group is different from both the normal control group and the glaucoma group. The disc area of the congenital glaucomas was not statistically different from the megalopapillas, but it was in terms of rim volume and other parameters. megalopapilla is an entity characterized by a large optic nerve head which may appear abnormal, with an increased cup, but associated with a normal rim volume, normal visual field and normal IOP. Special attention should be given to its differentiation from pseudoglaucomatous diseases. The frequency of megalopapillas seems to be quite higher than in congenital optic nerve head anomalies, but is has been virtually ignored by the literature worldwide so far.

Interobserver Agreement of Heidelberg Retina Tomograph Parameters

To measure the interobserver agreement of Heidelberg Retina Tomograph (HRT; Heidelberg Engineering, Heidelberg, Germany) parameters as a result of different observers' contour line placement. The optic nerve heads of 50 patients with glaucoma were imaged with the HRT. Five observers traced each disc margin with a contour line. Each observer was masked to the contour line tracings of the other observers, and there was no formal discussion as to where to place the contour line. The following stereometric parameters were calculated for each image for each observer: disc area, mean height of contour, cup shape, rim volume using the standard reference plane from software version 1.11, rim volume using a reference plane of 320 microns below the retinal plane, and volume above curved surface. Agreement between the five observers was tested for each parameter using intraclass correlation coefficients (ICCs). Interobserver agreement between the five observers was substantial for both rim volumes (ICC = 0.73) and for disc area (ICC = 0.67). Agreement was almost perfect for mean height of contour (ICC = 0.94), cup shape (ICC = 0.92), and volume above curved surface (ICC = 0.83). The interobserver agreement for the HRT parameters was substantial to almost perfect, indicating that the HRT results as defined by the five observers were interchangeable.

A Refined Method of Measuring Basal Crown and Cusp Areas by Use of a Three-dimensional Digitizing System.

In measuring basal crown and cusp areas of molars, one must determine a standard reference plane on which the projected measurements are made. In this paper, we present a new three-dimensionally based system which enables an objective determination of crown orientation. This is done by combining five laser scanned images of a molar taken occlusally and from four oblique angles to form a composite three-dimensional representation of the entire molar crown surface. Using this digitized data set, we derive a standard occlusal orientation that maximizes projected occlusal surface area. We can also choose other orientations for projection, such as those defined by the cervical line or cusp apices. Crown and cusp areas were measured in each of these orientations and compared for discrepancies on a mandibular first molar of Australopithecus afarensis. We found that orientations differ by more than 10 degrees, resulting in large discrepancies in cusp area values. It is concluded that, to enable reliable interpretation of cusp area data, whatever orientation methods used should be carefully chosen and rigidly followed.

Multiarchitectonic and stereotactic atlas of the human thalamus.

To improve anatomical definition and stereotactic precision of thalamic targets in neurosurgical treatments of chronic functional disorders, a new atlas of the human thalamus has been developed. This atlas is based on multiarchitectonic parcellation in sections parallel or perpendicular to the standard intercommissural reference plane. The calcium-binding proteins parvalbumin (PV), calbindin D-28K (CB), and calretinin (CR) were used as neurochemical markers to further characterize thalamic nuclei and delimit subterritories of functional significance for stereotactic explorations. Their overall distribution reveals a subcompartmentalization of thalamic nuclei into several groups. Predominant PV immunostaining characterizes primary somatosensory, visual and auditory nuclei, the ventral lateral posterior nucleus, reticular nucleus (R), and to a lesser degree also, lateral part of the centre median nucleus, and anterior, lateral, and inferior divisions of the pulvinar complex. In contrast, CB immunoreactivity is prevalent in medial thalamic nuclei (intralaminar and midline), the posterior complex, ventral posterior inferior nucleus, the ventral lateral anterior nucleus, ventral anterior, and ventral medial nuclei. The complementary distributions of PV and CB appear to correlate with distinct lemniscal and spinothalamic somatosensory pathways and to cerebellar and pallidal motor territories, respectively. Calretinin, while overlapping with CB in medial thalamic territories, is also expressed in R and limbic associated anterior group nuclei that contain little or no CB. Preliminary analysis indicates that interindividual nuclear variations cannot easily be taken into account by standardization procedures. Nevertheless, some corrections in antero-posterior coordinates in relation to different intercommissural distances are proposed.

Zum Einfluß der Konturlinie auf die Exkavationsfläche beim Heidelberg Retina Tomograph

Significance of topometric follow-up examinations of the optic nerve head in glaucomatous eyes depends on the reproducibility of the calculated parameters. Since the definition of the standard reference plane in software version 1.11 of the Heidelberg Retina Tomograph has been changed, intrapapillary parameters depend directly on the position of the contourline in the sector between -10 degrees to -4 degrees, and therefore on the observer variability to determine the disc border. We evaluated intra- and interobserver variability and present a simple approach to increase reproducibility. The disc border of 4 glaucomatous eyes, 3 ocular hypertensive eyes and 3 eyes of healthy subjects were traced by two observers, 5 times using the free draw mode and 5 times by the addition of contourline circles. We found a median variability of the mean disc radius in sector -10 degrees to -4 degrees of 51 microns, which defines the position of the standard reference plane, resulting in a median variability of the position of the standard reference plane of 33 microns which caused a variability of 81 microns2 of the cup area. Addition of contourline circles smoothing the final contourline along the border of the optic disc resulted in a decrease of the coefficient of variation of the standard reference plane of 3.76% (6.76% vs. 3.0%), of the cup area of 2.34% (3.87% vs. 1.53%) and of the rim volume of 3.41% (9.75% vs. 6.34%). The calculation of the cup area using software version 1.11 of the Heidelberg Retina Tomograph depends on observer variability. The addition of contourline circles to define the final contourline along the disc border increases reproducibility. However, in follow-up of topometric examinations of the optic nerve head the software supported transfer mode should be used. Comparing topometric data of an individual optic disc in follow-up suppose the same definition of the contourline. Therefore, topometric data evaluated using software version 1.10 or earlier needs to be recalculated.