Estimating Nephron Number from Biopsies: Impact on Clinical Studies

2021 ◽  
pp. ASN.2021070998
Author(s):  
Darya Morozov ◽  
Neda Parvin ◽  
Mark Conaway ◽  
Gavin Oxley ◽  
Edwin Baldelomar ◽  
...  
Keyword(s):  
Clinical Studies ◽  
Kidney Biopsy ◽  
Three Dimensional ◽  
Nephron Number ◽  
Resonance Imaging ◽  
Cortical Volume ◽  
Multiple Biopsies ◽  
Single Nephron ◽  
The Mean ◽  
Single Kidney

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.

scholarly journals 3D 3He diffusion MRI as a local in vivo morphometric tool to evaluate emphysematous rat lungs

2008 ◽  
Vol 105 (4) ◽  
pp. 1291-1300 ◽  
Author(s):  
R. E. Jacob ◽  
K. R. Minard ◽  
G. Laicher ◽  
C. Timchalk
Keyword(s):  
Diffusion Mri ◽  
Histological Analysis ◽  
Local Level ◽  
Three Dimensional ◽  
Resonance Imaging ◽  
Diffusion Weighted Images ◽  
Air Space ◽  
Entire Lung ◽  
The Mean

In this work, we investigate 3He magnetic resonance imaging as a noninvasive morphometric tool to assess emphysematous disease state on a local level. Emphysema was induced intratracheally in rats with 25 U/100 g body wt of porcine pancreatic elastase dissolved in 200 μl saline. Rats were then paired with saline-dosed controls. Nine three-dimensional (3D) 3He diffusion-weighted images were acquired at 1, 2, or 3 wk postdose, after which the lungs were harvested and prepared for histological analysis. Recently introduced indexes sensitive to the heterogeneity of the air space size distribution were calculated. These indexes, D1 and D2, were derived from the moments of the mean equivalent airway diameters. Averaged over the entire lung, it is shown that the average 3He diffusivity ( Dave) correlates well with histology ( R = 0.85, P < 0.0001). By matching small (0.046 cm2) regions in 3He images with corresponding regions in histological slices, Dave correlates significantly with both D 1 and D 2 ( R = 0.88 and R = 0.90, respectively, with P < 0.0001). It is concluded that 3He MRI is a viable noninvasive morphometric tool for localized in vivo emphysema assessment.

Electron Holographic Nano-Characterization of Gold Catalyst at Interface

2002 ◽  
Vol 727 ◽  
Author(s):  
S. Ichikawa ◽  
T. Akita ◽  
M. Okumura ◽  
M. Haruta ◽  
K. Tanaka
Keyword(s):  
Contact Angle ◽  
Titanium Oxide ◽  
Gold Catalyst ◽  
Three Dimensional ◽  
High Resolution Electron Microscopy ◽  
Electron Holography ◽  
Gold Particles ◽  
Oxide Support ◽  
The Mean ◽  
A Charge

AbstractThe catalytic properties of nanostructured gold catalyst are known to depend on the size of the gold particles and to be activated when the size decreases to a few nanometers. We investigated the size dependence of the three-dimensional nanostructure on the mean inner potential of gold catalysts supported on titanium oxide using electron holography and high-resolution electron microscopy (HREM). The contact angle of the gold particles on the titanium oxide tended to be over 90° for gold particles with a size of over 5 nm, and below 90° for a size of below 2 nm. This decreasing change in the contact angle (morphology) acts to increase the perimeter and hence the area of the interface between the gold and titanium oxide support, which is considered to be an active site for CO oxidation. The mean inner potential of the gold particles also changed as their size decreased. The value of the inner potential of gold, which is approximately 25 V in bulk state, rose to over 40 V when the size of the gold particles was less than 2 nm. This phenomenon indicates the existence of a charge transfer at the interface between gold and titanium oxide. The 3-D structure change and the inner potential change should be attributed to the specific electronic structure at the interface, owing to both the “nano size effect” and the “hetero-interface effect.”

Computed Tomography and Magnetic Resonance Imaging-aided Diagnosis of Primary Essential Cutis Verticis Gyrata: A Case Report with 5-year Follow-up and Review of the Literature

2019 ◽  
Vol 15 (9) ◽  
pp. 906-910
Author(s):  
Hongzhang Zhu ◽  
Shi-Ting Feng ◽  
Xingqi Zhang ◽  
Zunfu Ke ◽  
Ruixi Zeng ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Three Dimensional ◽  
Stable Condition ◽  
Resonance Imaging ◽  
Mri Findings ◽  
Cutis Verticis Gyrata ◽  
Essential Form ◽  
History Of ◽  
Magnetic Resonance Imaging Mri

Background: Cutis Verticis Gyrata (CVG) is a rare skin disease caused by overgrowth of the scalp, presenting as cerebriform folds and wrinkles. CVG can be classified into two forms: primary (essential and non-essential) and secondary. The primary non-essential form is often associated with neurological and ophthalmological abnormalities, while the primary essential form occurs without associated comorbidities. Discussion: We report on a rare case of primary essential CVG with a 4-year history of normal-colored scalp skin mass in the parietal-occipital region without symptom in a 34-year-old male patient, retrospectively summarizing his pathological and Computer Tomography (CT) and magnetic resonance imaging (MRI) findings. The major clinical observations on the CT and MR sectional images include a thickened dermis and excessive growth of the scalp, forming the characteristic scalp folds. With the help of CT and MRI Three-dimensional (3D) reconstruction techniques, the characteristic skin changes could be displayed intuitively, providing more evidence for a diagnosis of CVG. At the 5-year followup, there were no obvious changes in the lesion. Conclusion: Based on our observations, we propose that not all patients with primary essential CVG need surgical intervention, and continuous clinical observation should be an appropriate therapy for those in stable condition.

The Kaplan Fibers of the Iliotibial Band Can Be Identified on Routine Knee Magnetic Resonance Imaging

2019 ◽  
Vol 47 (12) ◽  
pp. 2895-2903 ◽  
Author(s):  
Lachlan Batty ◽  
Jerome Murgier ◽  
Richard O’Sullivan ◽  
Kate E. Webster ◽  
Julian A. Feller ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Sagittal Plane ◽  
Interobserver Reliability ◽  
Joint Line ◽  
Coronal Plane ◽  
Iliotibial Band ◽  
Resonance Imaging ◽  
Lateral Gastrocnemius ◽  
The Mean

Background: The Kaplan fibers (KFs) of the iliotibial band have been suggested to play a role in anterolateral rotational instability of the knee, particularly in the setting of an anterior cruciate ligament (ACL) rupture. Description of the normal magnetic resonance imaging (MRI) anatomy of the KFs may facilitate subsequent investigation into the MRI signs of injury. Purpose: To assess if the KF complex can be identified on 3-T MRI using standard knee protocols. Study Design: Cohort study (diagnosis); Level of evidence, 3. Methods: 3-T MRI scans of 50 ACL-intact knees were reviewed independently by a musculoskeletal radiologist and 2 orthopaedic surgeons. Identification of the KFs was based on radiological diagnostic criteria developed a priori. Identification of the KFs in the sagittal, coronal, and axial planes was recorded. Interobserver reliability was assessed using the Kappa statistic. Detailed anatomy including distance to the joint line and relationship to adjacent structures was recorded. Results: The mean patient age was 43 years (range, 15-81 years), 58% were male, and 50% were right knees. The KFs were identified by at least 2 reviewers on the sagittal images in 96% of cases, on the axial images in 76% of cases, and on the coronal images in 4% of cases. The mean distance from the KF distal femoral insertion to the lateral joint line was 50.1 mm (SD, 6.6 mm) and the mean distance to the lateral gastrocnemius tendon origin was 10.8 mm (SD, 8.6 mm). The KFs were consistently identified immediately anterior to the superior lateral geniculate artery on sagittal imaging. Interobserver reliability for identification was best in the sagittal plane (Kappa 0.5) and worst in the coronal plane (Kappa 0.1). Conclusion: The KF complex can be identified on routine MRI sequences in the ACL-intact knee; however, there is low to moderate interobserver reliability. Imaging in the sagittal plane had the highest rate of identification and the coronal plane the lowest. There is a consistent relationship between the most distal KF femoral attachment and the lateral joint line, lateral gastrocnemius tendon, and superior lateral geniculate artery.

The Influence of Blade Wakes on the Performance of Interturbine Diffusers

1996 ◽  
Vol 118 (2) ◽  
pp. 347-352 ◽  
Author(s):  
R. G. Dominy ◽  
D. A. Kirkham
Keyword(s):  
Performance Modeling ◽  
Three Dimensional ◽  
Secondary Flows ◽  
Two Dimensional ◽  
Correct Performance ◽  
Analysis Methods ◽  
Flow Factor ◽  
The Mean ◽  
Lp Turbine

Interturbine diffusers provide continuity between HP and LP turbines while diffusing the flow upstream of the LP turbine. Increasing the mean turbine diameter offers the potential advantage of reducing the flow factor in the following stages, leading to increased efficiency. The flows associated with these interturbine diffusers differ from those in simple annular diffusers both as a consequence of their high-curvature S-shaped geometry and of the presence of wakes created by the upstream turbine. It is shown that even the simplest two-dimensional wakes result in significantly modified flows through such ducts. These introduce strong secondary flows demonstrating that fully three-dimensional, viscous analysis methods are essential for correct performance modeling.

scholarly journals Proximity of the middle meningeal artery and maxillary artery to the mandibular head and mandibular neck as revealed by three-dimensional time-of-flight magnetic resonance angiography

2021 ◽  
Author(s):  
Daphne Schönegg ◽  
Raphael Ferrari ◽  
Julian Ebner ◽  
Michael Blumer ◽  
Martin Lanzer ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Magnetic Resonance Angiography ◽  
Three Dimensional ◽  
Time Of Flight ◽  
Middle Meningeal Artery ◽  
Individual Variability ◽  
Maxillary Artery ◽  
Condylar Process ◽  
The Mean ◽  
Meningeal Artery

Abstract Purpose The close topographic relationship between vascular and osseous structures in the condylar and subcondylar region and marked variability in the arterial course has been revealed by both imaging and cadaveric studies. This study aimed to verify the previously published information in a large sample and to determine a safe surgical region. Methods We analyzed the three-dimensional time-of-flight magnetic resonance angiography images of 300 individuals. Results The mean distance between the middle meningeal artery and the apex of the condyle or the most medial point of the condyle was 18.8 mm (range: 11.2–25.9 mm) or 14.5 mm (range: 8.8–22.9 mm) respectively. The course of the maxillary artery relative to the lateral pterygoid muscle was medial in 45.7% of cases and lateral in 54.3%. An asymmetric course was evident in 66 patients (22%). The mean distance between the maxillary artery and condylar process at the deepest point of the mandibular notch was 6.2 mm in sides exhibiting a medial course (range: 3.7–9.8 mm) and 6.6 mm in sides exhibiting a lateral course (range: 3.9–10.4 mm). The distances were significantly influenced by age, gender, and the course of the maxillary artery. Conclusion Our study emphasizes the marked inter- and intra-individual variability of the maxillary and middle meningeal arterial courses. We confirmed the proximity of the arteries to the condylar process. Extensive surgical experience and thorough preparation for each individual case are essential to prevent iatrogenic vascular injury.

scholarly journals Interactions between Tandem Cylinders in an Open Channel: Impact on Mean and Turbulent Flow Characteristics

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1718
Author(s):  
Hasan Zobeyer ◽  
Abul B. M. Baki ◽  
Saika Nowshin Nowrin
Keyword(s):  
Turbulent Flow ◽  
Open Channel ◽  
Recirculation Zone ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Flow Recirculation ◽  
Tandem Cylinders ◽  
Flow Development ◽  
The Mean ◽  
Recirculation Length

The flow hydrodynamics around a single cylinder differ significantly from the flow fields around two cylinders in a tandem or side-by-side arrangement. In this study, the experimental results on the mean and turbulence characteristics of flow generated by a pair of cylinders placed in tandem in an open-channel flume are presented. An acoustic Doppler velocimeter (ADV) was used to measure the instantaneous three-dimensional velocity components. This study investigated the effect of cylinder spacing at 3D, 6D, and 9D (center to center) distances on the mean and turbulent flow profiles and the distribution of near-bed shear stress behind the tandem cylinders in the plane of symmetry, where D is the cylinder diameter. The results revealed that the downstream cylinder influenced the flow development between cylinders (i.e., midstream) with 3D, 6D, and 9D spacing. However, the downstream cylinder controlled the flow recirculation length midstream for the 3D distance and showed zero interruption in the 6D and 9D distances. The peak of the turbulent metrics generally occurred near the end of the recirculation zone in all scenarios.

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