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Acute kidney injury (AKI) in premature neonates is common due to the administration of life‐saving therapies. The impact of AKI on renal morphology and susceptibility to further renal damage is poorly understood. Recent advances in radiological imaging have allowed integration of soft tissue morphology in the intact organ, facilitating a more complete understanding of changes in tissue microstructure associated with pathology. Here, we applied magnetic resonance imaging (MRI) to detect both glomerular and vascular changes in a rabbit model of neonatal AKI, induced by indomethacin and gentamicin. Using combined spin‐echo MRI and cationic ferritin enhanced gradient‐echo MRI (CFE‐MRI), we observed (a) an increased cortical arterial diameter in the AKI cohort compared to healthy controls, and (b) focal loss of vascular density and glomerular loss in a circumferential band ~1 mm from the cortical surface. This combined use of vascular and glomerular imaging may give insight into the etiology of AKI and its impact on renal health later in life.

Background: Accumulating evidence supports an association between nephron number and susceptibility to kidney disease. However, it is not currently possible to directly measure nephron number in a clinical setting. Recent clinical studies have used glomerular density from a single biopsy and whole kidney cortical volume from imaging to estimate both nephron number and single nephron glomerular filtration rate. However, the accuracy of these estimates from individual subjects is unknown. Furthermore, it is not clear how sample size or biopsy location may influence these estimates. These questions are critical to study design and to the potential translation of these tools to estimate nephron number in individual subjects. Methods: We measured the variability in estimated nephron number derived from needle or virtual biopsies and cortical volume in human kidneys declined for transplantation. We performed multiple needle biopsies in the same kidney, and examined the three-dimensional spatial distribution of nephron density by magnetic resonance imaging. We determined the accuracy of a single kidney biopsy to predict the mean nephron number estimated from multiple biopsies from the same kidney. Results: A single needle biopsy had a 15% chance and virtual biopsy had a 60% chance of being within 20% of whole kidney nephron number. Single needle biopsies could be used to detect differences in nephron number between large cohorts of several hundred subjects. Conclusions: The number of subjects required to accurately detect differences in nephron number between populations can be predicted based on natural intra-kidney variability in glomerular density. A single biopsy is insufficient to accurately predict nephron number in individual subjects.

Kidney pathologies are often highly heterogenous. To comprehensively understand kidney structure and pathology, it is critical to develop tool to map tissue microstructure in the context of the whole, intact organ. Magnetic resonance imaging (MRI) can provide a unique, three-dimensional (3D) view of the kidney and allows for measurement of multiple pathologic features. Here, we develop a platform to systematically render and map gross and microstructural features of the human kidney based on 3D MRI. These features include pyramid number and morphology, and associated medulla and cortex. in a subset of these kidneys, we also map individual glomeruli and glomerular volumes using cationic ferritin enhance-MRI to report intra-renal heterogeneity in glomerular density and size. Finally, we render and measure regions of nephron loss due to pathology and individual glomerular volumes in each pyramidal unit. This work provides new tools to comprehensively evaluate the kidney across scales, with potential applications in anatomical and physiological research, transplant allograft evaluation, biomarker development, biopsy guidance, and therapeutic monitoring. These image rendering and analysis tools could eventually impact the field of transplantation medicine to improve longevity matching of donor allografts and recipients and reduce discard rates through the direct assessment of donor kidneys.

Purpose: To make noninvasive measurements of temperature in the posterior chamber (vitreous) of the eye using diffusion-based thermometry (DBT) magnetic resonance imaging (MRI) and to explain variability in these measurements due to choice of b-value and the effects of motion. Methods: Phantom studies of human vitreous and distilled water were performed using b-values from 0 to 1500 s/mm 2 to determine the liquid-specific calibration factor for vitreous as well as to determine the temperature offsets due to sampling the diffusion curve using three higher routine clinical b-values (b = 0, 500, 1000 s/mm 2) or four lower b-values (b = 0, 200, 400, 600 s/mm 2), thought to be optimized for fluids. Retrospective ROI-based measurements of apparent diffusion coefficient on single slices as well as multi-slice histograms of the eyes were made in six patients with peri-orbital cellulitis and 11 age-matched controls, to assess for temperature changes in the presence of periorbital inflammation. A prospective study of ten repeated measurements of eye temperature using both high and lower b-value sampling was performed in ten asymptomatic volunteers to determine the reproducibility of eye temperature measurements in-vivo as well as to estimate vitreous temperature in the absence of motion. Results: The diffusion coefficient of vitreous (2,088 AE 13 × 10 −6 mm 2 /s) was significantly lower (−1.9%, P < 0.001) compared to distilled water (2,128 AE 12 × 10 −6 mm 2 /s). The calibration factor for temperature measurements of vitreous using DBT is +0.74 AE 0.06°C. Temperature offsets were smaller (<−0.2°C, P < 0.01) when using larger routine clinical b-values to estimate the diffusion coefficient compared to using a series of lower b-values (<−1.0°C, P < 0.001). Two-dimensional singleslice ROI-based measurement showed significant temperature differences (ΔT I-C = 2.5 AE 1.2°C, P < 0.001) between the eyes of patient with peri-orbital cellulitis, higher on the side of inflammation. There was no significant difference in eye temperature when using the 3D histogram (which is likely due to motion averaging as significant slice-to-slice variation was present). However, significant differences in the 3D temperature histograms between the two eyes was observed in one out of six patients. Prospective eye temperature measurements in healthy volunteers showed significant intra-and intersubject variability (33.8-41.6°C), which was caused by eye motion. This resulted in +2.4°C cohortwide elevation in temperature when three b-values were used and +4.7°C when four b-values were used. Using a pattern of elevated temperature at the periphery of the eye to detect motion, eye temperature is the absence of motion was estimated to be 34.5 AE 0.4°C with three higher b-values and 34.6 AE 1.9°C with four lower b-values; this temperature corresponds with prior mathematical simulations of eye temperature as well as boundary conditions. Conclusions: Globe vitreous temperature has been measured noninvasively using DBT MRI. Using routine clinical b-values of b...

Tubular pathologies are a common feature of kidney disease. Current metrics to assess kidney health, in vivo or in transplant, are generally based on urinary or serum biomarkers and pathologic findings from kidney biopsies. Biopsies, usually taken from kidney cortex, are invasive and prone to sampling error. Tools to directly and non-invasively measure tubular pathology could provide a new approach to assess kidney health. This study uses diffusion magnetic resonance imaging (dMRI) as a non-invasive tool to measure the size of the tubular lumen in ex vivo, perfused kidneys. We first used Monte-Carlo simulations to demonstrate that dMRI is sensitive to restricted tissue water diffusion at the scale of the kidney tubule. We applied dMRI and biophysical modeling to examine the distribution of tubular diameters in ex vivo, fixed kidneys from mice, rats, and a human donor. The biophysical model to fit the dMRI signal was based on a superposition of freely diffusing water and water diffusing inside infinitely long cylinders of different diameters. Tubular diameters measured by MRI were within 10% of those measured by histology within the same tissue. Finally, we applied dMRI to investigate kidney pathology in a mouse model of folic-acid induced acute kidney injury (AKI). dMRI detected heterogeneity in the distribution of tubules within kidney cortex of AKI mice compared to the control group. We conclude that dMRI can be used to measure the distribution of tubule diameters in the kidney cortex ex vivo and dMRI may provide a new non-invasive biomarker of tubular pathology.

The immense progress of new technology we have been created an enormous number of digital images by using such devices as a digital camera, scanner, and mobile phones so on. All the images which are taken by the devices to keep in Image Database. For retrieving the desire images which were given in an input image has compared with the large database according to the visual content used by the technique as referred to as the Content Based Image Retrieval (CBIR) system. There are two phases for retrieving images in the CBIR system, as the first one is feature extraction and the second one is similarity size. Thus, the feature extraction consists of every image has produced symbolic content in the form of the function. The visual contents of an image in the CBIR system contain the features which have represented as shape, texture, spatial region and color of the images. In our paper tries to design the images’ color features as in the steps to focus color representation in the k-d tree, CIELAB color space of color signature compression along with categories of Human’s color for Content-based image retrieval and also acquire the results using MATLAB.

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