Connectivity-based localization of human hypothalamic nuclei in functional images of standard voxel size.

Despite their critical roles in autonomic functions, individual hypothalamic nuclei have not been extensively investigated in humans using functional magnetic resonance imaging, partly due to the difficulty in resolving individual nuclei contained in the small structure of the hypothalamus. Areal parcellation analyses enable discrimination of individual hypothalamic nuclei but require a higher spatial resolution, which necessitates long scanning time or large amounts of data to compensate for the low signal-to-noise ratio in 3T or 1.5T scanners. In this study, we present analytic procedures to estimate likely locations of individual nuclei in the standard 2-mm resolution based on our higher resolution dataset. The spatial profiles of functional connectivity with the cerebral cortex for each nucleus in the medial hypothalamus were calculated using our higher resolution dataset. Voxels in the hypothalamus in standard resolution images from the Human Connectome Project (HCP) database that predominantly shared connectivity profiles with the same nucleus were subsequently identified. Voxels representing individual nuclei, as identified with the analytic procedures, were reproducible across 20 HCP datasets of 20 subjects each. Furthermore, the identified voxels were spatially separate. These results suggest that these analytic procedures are capable of refining voxels that represent individual hypothalamic nuclei in standard resolution. Our results highlight the potential utility of these procedures in various settings such as patient studies, where lengthy scans are infeasible.

Quality and denoising in real-time functional magnetic resonance imaging neurofeedback: A methods review.

Neurofeedback training using real-time functional magnetic resonance imaging (rtfMRI-NF) allows subjects voluntary control of localised and distributed brain activity. It has sparked increased interest as a promising non-invasive treatment option in neuropsychiatric and neurocognitive disorders, although its efficacy and clinical significance are yet to be determined. In this work, we present the first extensive review of acquisition, processing and quality control methods available to improve the quality of the neurofeedback signal. Furthermore, we investigate the state of denoising and quality control practices in 128 recently published rtfMRI-NF studies. We found: (a) that less than a third of the studies reported implementing standard real-time fMRI denoising steps, (b) significant room for improvement with regards to methods reporting and (c) the need for methodological studies quantifying and comparing the contribution of denoising steps to the neurofeedback signal quality. Advances in rtfMRI-NF research depend on reproducibility of methods and results. Notably, a systematic effort is needed to build up evidence that disentangles the various mechanisms influencing neurofeedback effects. To this end, we recommend that future rtfMRI-NF studies: (a) report implementation of a set of standard real-time fMRI denoising steps according to a proposed COBIDAS-style checklist (https://osf.io/kjwhf/), (b) ensure the quality of the neurofeedback signal by calculating and reporting community-informed quality metrics and applying offline control checks and (c) strive to adopt transparent principles in the form of methods and data sharing and support of open-source rtfMRI-NF software. Code and data for reproducibility, as well as an interactive environment to explore the study data, can be accessed at https://github.com/jsheunis/quality-and-denoising-in-rtfmri-nf.

Development and Validation of an Image Analysis System for the Measurement of Cell Proliferation in Mammary Glands of Rats.

Reliable detection and measurement of cell proliferation are essential in the preclinical assessment of carcinogenic risk of therapeutics. In this context, the assessment of mitogenic potential on mammary glands is crucial in the preclinical safety evaluation of novel insulins. The existing manual counting is time-consuming and subject to operator bias. To standardize the processes, make it faster, and resistant to errors, we developed a semiautomated image analysis system (CEPA software, which is open-source) for counting of proliferating cells in photomicrographs of mammary gland sections of rats labeled with Ki-67. We validated the software and met the predefined targets for specificity, accuracy, and reproducibility. In comparison to manual counting, the respective mean differences in absolute labeling indices (LIs) for CEPA software were 3.12% for user 1 and 3.05% for user 2. The respective regression analysis revealed a good correlation between the CEPA software user and manual counting. Moreover, the CEPA software showed enhanced reproducibility between independent users. The interuser variability is centered around 0 and the absolute difference was about 0.53% LI. Based on validation data, our software has superiority to the manual counting and is a valid and reliable tool for the routine analysis of cell proliferation in mammary glands from rats exposed to insulin analogs.

Tractography optimization using quantitative T1 mapping in the human optic radiation.

Diffusion MRI tractography is essential for reconstructing white-matter projections in the living human brain. Yet tractography results miss some projections and falsely identify others. A challenging example is the optic radiation (OR) that connects the thalamus and the primary visual cortex. Here, we tested whether OR tractography can be optimized using quantitative T1 mapping. Based on histology, we proposed that myelin-sensitive T1 values along the OR should remain consistently low compared with adjacent white matter. We found that complementary information from the T1 map allows for increasing the specificity of the reconstructed OR tract by eliminating falsely identified projections. This T1-filtering outperforms other, diffusion-based tractography filters. These results provide evidence that the smooth microstructural signature along the tract can be used as constructive input for tractography. Finally, we demonstrate that this approach can be applied in a case of multiple sclerosis, and generalized to the HCP-available MRI measurements. We conclude that multimodal MRI microstructural information can be used to eliminate spurious tractography results in the case of the OR.

Individualized tractography-based parcellation of the globus pallidus pars interna using 7T MRI in movement disorder patients prior to DBS surgery.

The success of deep brain stimulation (DBS) surgeries for the treatment of movement disorders relies on the accurate placement of an electrode within the motor portion of subcortical brain targets. However, the high number of electrodes requiring relocation indicates that today's methods do not ensure sufficient accuracy for all patients. Here, with the goal of aiding DBS targeting, we use 7 Tesla (T) MRI data to identify the functional territories and parcellate the globus pallidus pars interna (GPi) into motor, associative and limbic regions in individual subjects. 7 T MRI scans were performed in seventeen patients (prior to DBS surgery) and one healthy control. Tractography-based parcellation of each patient's GPi was performed. The cortex was divided into four masks representing motor, limbic, associative and "other" regions. Given that no direct connections between the GPi and the cortex have been shown to exist, the parcellation was carried out in two steps: 1) The thalamus was parcellated based on the cortical targets, 2) The GPi was parcellated using the thalamus parcels derived from step 1. Reproducibility, via repeated scans of a healthy subject, and validity of the findings, using different anatomical pathways for parcellation, were assessed. Lastly, post-operative imaging data was used to validate and determine the clinical relevance of the parcellation. The organization of the functional territories of the GPi observed in our individual patient population agrees with that previously reported in the literature: the motor territory was located posterolaterally, followed anteriorly by the associative region, and further antero-ventrally by the limbic territory. While this organizational pattern was observed across patients, there was considerable variability among patients. The organization of the functional territories of the GPi was remarkably reproducible in intra-subject scans. Furthermore, the organizational pattern was observed consistently by performing the parcellation of the GPi via the thalamus and via a different pathway, going through the striatum. Finally, the active therapeutic contact of the DBS electrode, identified with a combination of post-operative imaging and post-surgery DBS programming, overlapped with the high-probability "motor" region of the GPi as defined by imaging-based methods. The consistency, validity, and clinical relevance of our findings have the potential for improving DBS targeting, by increasing patient-specific knowledge of subregions of the GPi to be targeted or avoided, at the stage of surgical planning, and later, at the stage when stimulation is adjusted.

Evaluating accuracy of striatal, pallidal, and thalamic segmentation methods: Comparing automated approaches to manual delineation.

Accurate automated quantification of subcortical structures is a greatly pursued endeavour in neuroimaging. In an effort to establish the validity and reliability of these methods in defining the striatum, globus pallidus, and thalamus, we investigated differences in volumetry between manual delineation and automated segmentations derived by widely used FreeSurfer and FSL packages, and a more recent segmentation method, the MAGeT-Brain algorithm. In a first set of experiments, the basal ganglia and thalamus of thirty subjects (15 first episode psychosis [FEP], 15 controls) were manually defined and compared to the labels generated by the three automated methods. Our results suggest that all methods overestimate volumes compared to the manually derived "gold standard", with the least pronounced differences produced using MAGeT. The least between-method variability was noted for the striatum, whereas marked differences between manual segmentation and MAGeT compared to FreeSurfer and FSL emerged for the globus pallidus and thalamus. Correlations between manual segmentation and automated methods were strongest for MAGeT (range: 0.51 to 0.92; p<0.01, corrected), whereas FreeSurfer and FSL showed moderate to strong Pearson correlations (range 0.44-0.86; p<0.05, corrected), with the exception of FreeSurfer pallidal (r=0.31, p=0.10) and FSL thalamic segmentations (r=0.37, p=0.051). Bland-Altman plots highlighted a tendency for greater volumetric differences between manual labels and automated methods at the lower end of the distribution (i.e. smaller structures), which was most prominent for bilateral thalamus across automated pipelines, and left globus pallidus for FSL. We then went on to examine volume and shape of the basal ganglia structures using automated techniques in 135 FEP patients and 88 controls. The striatum and globus pallidus were significantly larger in FEP patients compared to controls bilaterally, irrespective of the method used. MAGeT-Brain was more sensitive to shape-based group differences, and uncovered widespread surface expansions in the striatum and globus pallidus bilaterally in FEP patients compared to controls, and surface contractions in bilateral thalamus (FDR-corrected). By contrast, after using a recommended cluster-wise thresholding method, FSL only detected differences in the right ventral striatum (FEP>Control) and one cluster of the left thalamus (Control>FEP). These results suggest that different automated pipelines segment subcortical structures with varying degrees of variability compared to manual methods, with particularly pronounced differences found with FreeSurfer and FSL for the globus pallidus and thalamus.

Research on Techniques of Multifeatures Extraction for Tongue Image and Its Application in Retrieval.

Tongue diagnosis is one of the important methods in the Chinese traditional medicine. Doctors can judge the disease's situation by observing patient's tongue color and texture. This paper presents a novel approach to extract color and texture features of tongue images. First, we use improved GLA (Generalized Lloyd Algorithm) to extract the main color of tongue image. Considering that the color feature cannot fully express tongue image information, the paper analyzes tongue edge's texture features and proposes an algorithm to extract them. Then, we integrate the two features in retrieval by different weight. Experimental results show that the proposed method can improve the detection rate of lesion in tongue image relative to single feature retrieval.

Reliability testing of the patellofemoral joint reaction force (PFJRF) measurement during double-legged squatting in healthy subjects: a pilot study.

INTRODUCTION: Anterior knee pain or patellofemoral pain syndrome (PFPS) is supposed to be related to patellofemoral joint reaction forces (PFJRF). Measuring these forces may therefore provide reliable evidence for conservative treatments to correct probable malalignment in subjects with PFPS. The aim of the present study was to examine the reliability of PFJRF measurements during double-legged squatting in healthy subjects. METHODS: Using a motion analysis system and one forceplate, PFJRF of 10 healthy subjects were assessed during double-legged squatting. Data were collected from superficial markers taped to selected landmarks. This procedure was performed on the right knees, at three different knee flexion angles of 30, 45 and 60° during three separate double-legged squats. Subjects were then requested to repeat this test procedure on two separate test sessions at different occasions. The PFJRF was calculated using a biomechanical model of the patellofemoral joint. RESULTS: The data reveal an increase in PFJRF values (from mean, SD of 425.2, 35.5N to 1075.4, 70.1N)with an increase in the tibiofemoral joint angle during double-legged squatting. The CV (coefficient of variation) values during within and between session tests, revealed the high repeatability and reproducibility of PFJRF measurements, while the ICC (intra class correlation coefficient) values showed the low reliability of these measurements. CONCLUSION: The low reliability of PFJRF measurements suggests that the PFJRF measurement during double-legged squatting should be performed with caution with improving the method of kinetic measurement of the patellofemoral joint in healthy subjects.

Robust data processing and normalization strategy for MALDI mass spectrometric imaging.

Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) provides localized information about the molecular content of a tissue sample. To derive reliable conclusions from MSI data, it is necessary to implement appropriate processing steps in order to compare peak intensities across the different pixels comprising the image. Here, we review commonly used normalization methods, and propose a rational data processing strategy, for robust evaluation and modeling of MSI data. The approach includes newly developed heuristic methods for selecting biologically relevant peaks and pixels to reduce the size of a data set and remove the influence of the applied MALDI matrix. The methods are demonstrated on a MALDI MSI data set of a sagittal section of rat brain (4750 bins, m/z = 50-1000, 111 × 185 pixels) and the proposed preferred normalization method uses the median intensity of selected peaks, which were determined to be independent of the MALDI matrix. This was found to effectively compensate for a range of known limitations associated with the MALDI process and irregularities in MS image sampling routines. This new approach is relevant for processing of all MALDI MSI data sets, and thus likely to have impact in biomarker profiling, preclinical drug distribution studies, and studies addressing underlying molecular mechanisms of tissue pathology.

The reliability of the Associate Platinum digital foot scanner in measuring previously developed footprint characteristics: a technical note.

OBJECTIVE: An ink pad and paper, pressure-sensitive platforms, and photography have previously been used to collect footprint data used in clinical assessment. Digital scanners have been widely used more recently to collect such data. The purpose of this study was to evaluate the intra- and interrater reliability of a flatbed digital image scanning technology to capture footprint data. METHODS: This study used a repeated-measures design on 32 (16 male 16 female) healthy subjects. The following measured indices of footprint were recorded from 2-dimensional images of the plantar surface of the foot recorded with an Associate Platinum (Foot Levelers Inc, Roanoke, VA) digital foot scanner: Staheli index, Chippaux-Smirak index, arch angle, and arch index. Intraclass correlation coefficient (ICC) values were calculated to evaluate intrarater, interday, and interclinician reliability. RESULTS: The ICC values for intrarater reliability were greater than or equal to .817, indicating an excellent level of reproducibility in assessing the collected images. Analyses of variance revealed that there were no significant differences between raters for each index (P > .05). The ICC values also indicated excellent reliability (.881-.971) between days and clinicians in all but one of the indices of footprint, arch angle (.689), with good reliability between clinicians. The full-factorial analysis of variance model did not reveal any interaction effects (P > .05), which indicated that indices of footprint were not changing across days and clinicians. CONCLUSIONS: Scanning technology used in this study demonstrated good intra- and interrater reliability measurements of footprint indices, as demonstrated by high ICC values.

Reliability of a photographic method for assessing standing posture of elementary school students.

OBJECTIVE: A high prevalence of poor standing posture among elementary schoolchildren indicates the need for the introduction of school-based interventions for improvement of postural alignments. For assessing the effect of intervention programs, reliable quantitative measures of standing posture should be used. Therefore, the purpose of this study was to examine the reliability of a photographic method for assessment of standing posture among elementary schoolchildren. METHODS: The study was conducted on a convenience sample of 273 male students between 10 and 13 years old. Each subject was photographed in habitual standing posture, 3 times in a front view and 3 times in a side view. Deviations from ideal postural alignment were calculated with Posture Image Analyzer software and UTHSCSA ImageTool software. Interitem reliability was estimated using intraclass correlation coefficient. RESULTS: Intraclass correlation coefficients for posture deviations assessed with Posture Image Analyzer ranged from 0.81 for knee joints deviation and ankle joints deviation in the coronal plane to 0.92 for trunk deviation and knee joints deviation in the sagittal plane. Intraclass correlation coefficients for posture deviations assessed with UTHSCSA ImageTool ranged from 0.80 for knee joints deviation in the coronal plane to 0.91 for trunk deviation and knee joints deviation in the sagittal plane. CONCLUSIONS: This study showed a satisfactory interitem reliability of a photographic method for the assessment of standing posture among elementary schoolchildren.

Waxholm space: an image-based reference for coordinating mouse brain research.

We describe an atlas of the C57BL/6 mouse brain based on MRI and conventional Nissl histology. Magnetic resonance microscopy was performed on a total of 14 specimens that were actively stained to enhance tissue contrast. Images were acquired with three different MR protocols yielding contrast dependent on spin lattice relaxation (T1), spin spin relaxation (T2), and magnetic susceptibility (T2*). Spatial resolution was 21.5 mum (isotropic). Conventional histology (Nissl) was performed on a limited set of these same specimens and the Nissl images were registered (3D-to-3D) to the MR data. Probabilistic atlases for 37 structures are provided, along with average atlases. The availability of three different MR protocols, the Nissl data, and the labels provides a rich set of options for registration of other atlases to the same coordinate system, thus facilitating data-sharing. All the data is available for download via the web.

Image analysis benchmarking methods for high-content screen design.

The recent development of complex chemical and small interfering RNA (siRNA) collections has enabled large-scale cell-based phenotypic screening. High-content and high-throughput imaging are widely used methods to record phenotypic data after chemical and small interfering RNA treatment, and numerous image processing and analysis methods have been used to quantify these phenotypes. Currently, there are no standardized methods for evaluating the effectiveness of new and existing image processing and analysis tools for an arbitrary screening problem. We generated a series of benchmarking images that represent commonly encountered variation in high-throughput screening data and used these image standards to evaluate the robustness of five different image analysis methods to changes in signal-to-noise ratio, focal plane, cell density and phenotype strength. The analysis methods that were most reliable, in the presence of experimental variation, required few cells to accurately distinguish phenotypic changes between control and experimental data sets. We conclude that by applying these simple benchmarking principles an a priori estimate of the image acquisition requirements for phenotypic analysis can be made before initiating an image-based screen. Application of this benchmarking methodology provides a mechanism to significantly reduce data acquisition and analysis burdens and to improve data quality and information content.

European Society of Gastrointestinal and Abdominal Radiology (ESGAR): consensus statement on CT colonography.

Rapid clinical dissemination of CT colonography (CTC) is occurring in parallel with continued research into technique optimisation and diagnostic performance. A need exists therefore for current guidance as to basic prerequisites for effective clinical implementation. A questionnaire detailing CTC technique, analysis, training and clinical implementation was developed by the European Society of Gastrointestinal and Abdominal Radiology (ESGAR) CTC committee and circulated to all faculty members of previous ESGAR "hands-on" CTC training courses. Responses were collated and a consensus statement produced. Of 27 invited to participate, 24 responded. Reasonable consensus was reached on bowel preparation, colonic distension, patient positioning, use of IV contrast and optimal scan parameters. Both primary 2D and primary 3D analysis were advocated equally, with some evidence that more experienced readers prefer primary 2D. Training was universally recommended, although there was no consensus regarding minimum requirements. CTC was thought superior to barium enema, although recommended for screening only in the presence of validated local experience. There was consensus that polyps 4 mm or less could be ignored assuming agreement from local gastroenterological colleagues. There is increasing consensus amongst European experts as to the current best practice in CTC.

Technical innovations and the evolution of endoscopic sinus surgery.

Since the introduction of endoscopic sinus surgery, a number of significant technological advances, as well as an improved understanding of disease pathogenesis and management, have enabled major evolutions in surgical techniques. Modifications to surgical instruments, imaging, the development of the microdebrider, and other newer instrumentation have all contributed to the current level of patient success associated with endoscopic intranasal techniques. At the same time, it has become evident that anatomic variations are less important in the pathogenesis of chronic rhinosinusitis than was previously thought, and that ventilation alone is insufficient to resolve well-established disease. This paper reviews the changes that have occurred in endoscopic sinus surgery over the past 20 years since the techniques were first introduced into the United States, and the technologies that have enabled these changes and the development of extended endoscopic techniques. Continuing developments of interactive computer-guided surgery, endoscopic 3-dimensional imagery, robotics, and improved adjunctive therapies will further extend the role of endoscopic transnasal approaches to an expanded number of skull base and intracranial lesions.

[Fluoroscopic image capturing and DICOM storage application in the cardio-catheter room].

This paper analyses the data structure of DICOM standard by the applications in the Non-DICOM format fluoroscopic images converted into the DICOM format images. It puts forward a solution to integrate the Multi-Channel Electrophysiology Recorder System with the X -ray system in the cardio-catheter room.

MRI of congenital heart disease: a paradigm of collaboration. new suggestions for a team approach from Madigan Army Medical Center.

Over the past decade, there has been increasing use of cardiac MRI in the evaluation of children with congenital heart disease. There has also been an increased number of radiologists and pediatric cardiologists desiring to perform cardiac MRI in the evaluation of these patients. At the present time, the number of pediatric cardiologists and radiologists fully trained in the use of MRI studies for CHD is inadequate to provide this modality at all institutions with MRI capabilities. This article describes the collaborative approach between pediatric cardiology and radiology at Madigan Army Medical Center and its implications for patient care and credentialing.

Clinical quality assessment using computer monitor photoimages of optic nerve head cupping.

BACKGROUND: Photo documentation (color slides) of abnormal optic nerve heads enable the clinician to accurately access or estimate the percentage of the optic nerve cupping to quantify the progression of glaucoma. The purpose of this study is to compare cupping estimations using digital images on a computer monitor to those using standard color slides. METHODS: Ten sets of stereo optic nerve head photos from six glaucoma suspects were used in this study. A set is two 35-mm pictures of one optic nerve head. The film was developed as standard color slides using Seattle Filmworks slide developing. The computer monitor photoimages used Seattle Photoworks software for photos on disk. Thirteen experienced examiners estimated cupping on the 10 sets of color slides and on the 10 sets of digital images. Standard criterion was used to estimate the C/D percentage. We used a three-way mixed model ANOVA experimental design to analyze the data. RESULTS: Examiner estimations of C/D differed slightly between color slides and computer monitor photoimages (mean C/D of 61.1% for slides to 63.7% for monitor). This difference was statistically significant (p = 0.033). The differences authors found were not clinically significant (10%) in 7 out of the 10 optic nerve head photos using the accepted standard of interexaminer reliability. The variations of the examiner estimations as well as interexaminer differences will be discussed. CONCLUSION: The use of a computer image photodisplay of an optic nerve head has a potential as an alternative to traditional slide photodocumentation. This study identifies problems which require more work to make these computer images the equivalent of color slides.