Diabetes is Associated with a Lower Minimum Moment of Inertia Among Older Women: An Analysis of 3D Reconstructions of Clinical CT Scans

This problem is a generalization of the classical problem of the stability of a spinning rigid body. We obtain the stability chart by using: (i) the computer algebra system MACSYMA in conjunction with a perturbation method, and (ii) numerical integration based on Floquet theory. We show that the form of the stability chart is different for each of the three cases in which the spin axis is the minimum, maximum, or middle principal moment of inertia axis. In particular, a rotation with arbitrarily small angular velocity about the maximum moment of inertia axis can be made unstable by appropriately choosing the model parameters. In contrast, a rotation about the minimum moment of inertia axis is always stable for a sufficiently small angular velocity. The MACSYMA program, which we used to obtain the transition curves, is included in the Appendix.

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The metopic index: an anthropometric index for the quantitative assessment of trigonocephaly from metopic synostosis

Journal of Neurosurgery Pediatrics ◽

10.3171/2016.2.peds15524 ◽

2016 ◽

Vol 18 (3) ◽

pp. 275-280 ◽

Cited By ~ 6

Author(s):

Joanna Y. Wang ◽

Amir H. Dorafshar ◽

Ann Liu ◽

Mari L. Groves ◽

Edward S. Ahn

Keyword(s):

Quantitative Assessment ◽

Surgical Repair ◽

Preoperative Evaluation ◽

Ct Scans ◽

Control Group ◽

3D Reconstructions ◽

Metopic Synostosis ◽

The Mean ◽

Age Range ◽

Age And Sex

OBJECTIVE Because the metopic suture normally fuses during infancy, there are varying degrees of severity in head shape abnormalities associated with premature fusion. A method for the objective and reproducible assessment of metopic synostosis is needed to guide management, as current methods are limited by their reliance on aesthetic markers. The object of this study was to describe the metopic index (MI), a simple anthropometric cranial measurement. The measurements can be obtained from CT scans and, more importantly, from palpable cranial landmarks, and the index provides a rapid tool for evaluating patients in both pre- and postoperative settings. METHODS High-resolution head CT scans obtained in 69 patients (age range 0–24 months) diagnosed with metopic craniosynostosis were retrospectively reviewed. Preoperative 3D reconstructions were available in 15 cases, and these were compared with 3D reconstructions of 324 CT scans obtained in a control group of 316 infants (age range 0–24 months) who did not have any condition that might affect head size or shape and also in a subset of this group, comprising 112 patients precisely matched to the craniosynostosis patients with respect to age and sex. Postoperative scans were available and reviewed in 9 of the craniosynostosis patients at a mean time of 7.1 months after surgical repair. 3D reconstructions of these scans were matched with controls based upon age and sex. RESULTS The mean preoperative MI for patients with trigonocephaly was 0.48 (SD 0.05), significantly lower than the mean values of 0.57 (SD 0.04) calculated on the basis of all 324 scans obtained in controls (p < 0.001) and 0.58 (SD 0.04) for the subset of 112 age- and sex-matched controls (p < 0.001). For 7 patients with both pre- and postoperative CT scans available for evaluation, the mean postoperative MI was 0.55 (SD 0.03), significantly greater than their preoperative MIs (mean 0.48 [SD 0.04], p = 0.001) and comparable to the mean MI of the controls (p = 0.30). In 4 patients, clinically obtained postoperative MIs by caliper measurement were comparable to measurements derived from CT (p = 0.141). CONCLUSIONS The MI is a useful measurement of the severity of trigonocephaly in patients with metopic synostosis. This simple quantitative assessment can potentially be used in the clinical setting to guide preoperative evaluation, surgical repair, and postoperative degree of correction.

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The Role of 3D Reconstruction True Volume Analysis in Osteochondral Lesions of the Talus

Foot & Ankle Orthopaedics ◽

10.1177/2473011418s00127 ◽

2018 ◽

Vol 3 (3) ◽

pp. 2473011418S0012

Author(s):

Kempland Walley ◽

Tyler Gonzalez ◽

Evan Roush ◽

Kaitlin Saloky ◽

Ryan Callahan ◽

...

Keyword(s):

Imaging Modality ◽

Cartilage Damage ◽

Ct Scans ◽

Osteochondral Lesions ◽

Ct Scanner ◽

3D Reconstructions ◽

Volume Analysis ◽

Orthopedic Surgeons ◽

Damage Stability ◽

Conventional Ct

Category: Other Introduction/Purpose: Evaluation and management of osteochondral lesions of the talus (OLTs) often warrant advanced imaging studies such as CT and/or MRI. While MRI has its advantages in determining the degree of cartilage damage, stability of the fragment and edema, CT imaging is better delineates the osseous anatomy and extent of the lesion. The latter imaging modality offers increasing acuity and resolution in characterizing the complex osteochondral landscape via three-dimensional (3D) reconstructions. It is possible that orthopedic surgeons may overestimate the size and misinterpret the morphology of OLT from conventional MRI and CT thereby influencing treatment strategies. The purpose of this study is to determine the utility of a novel means to estimate the true-volume of OLTs using 3D reconstructed images and volume analysis. Methods: After IRB approval, an institutional radiology database was queried for patients with OLTs and compatible CT scans between 2011 and 2016. Fourteen patients were found to have OLT compatible with the software used to approximate true-volumes of 3D reconstructed images. 3D reconstructions were created using Mimics software (Materialise, Belgium). From the 14 reconstructed OLTs, 5 were randomly selected for evaluation. 10 orthopedic surgeons independently estimated the volume of these 5 OLTs via standard CT scans. Then 3D reconstructions were made and true-volume (TV) analysis measurements of each OLT were generated. The percent change in volumes from CT were compared to TVs determined from 3D reconstructive analysis. Results: On average the volume calculated by conventional CT scanner grossly overestimated the actual size of the OLTs. The volume calculated on conventional CT scanner overestimated the size of OLTs compared to the 3D TV reconstructed analysis by 285-864%. Conclusion: Our results show that conventional measurements of OLTS with CT grossly overestimates the size of the lesion by up to 8-times the actual lesion size. This overestimation of volumes of the lesion can drastically change surgical planning and may lead to unnecessary costs associated with specific surgical treatments. With the use of our newly defined model for volume measurement in OLTs, we can more accurately predict the exact size of the OLT. This can better guide surgeons to choices both the correct cartilage restoring procedure as well as the need for bone grafting.

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The upper bound of minimum moment of inertia of equi-area convex domains

Journal of the Franklin Institute ◽

10.1016/0016-0032(74)90122-7 ◽

1974 ◽

Vol 297 (6) ◽

pp. 457-466

Author(s):

Nassir Monemi ◽

Arsalan Ghahramani

Keyword(s):

Upper Bound ◽

Moment Of Inertia ◽

Convex Domains ◽

Minimum Moment

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CT scans and 3D reconstructions of Florida manatee (Trichechus manatus latirostris) heads and ear bones

Hearing Research ◽

10.1016/j.heares.2007.01.029 ◽

2007 ◽

Vol 228 (1-2) ◽

pp. 123-135 ◽

Cited By ~ 14

Author(s):

Marie E. Chapla ◽

Douglas P. Nowacek ◽

Sentiel A. Rommel ◽

Valerie M. Sadler

Keyword(s):

Ct Scans ◽

Florida Manatee ◽

Trichechus Manatus ◽

3D Reconstructions ◽

Trichechus Manatus Latirostris

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An Elastorelaxometer for Large Reversible Deformation of Elastomeric Systems and Polymer Solutions

Rubber Chemistry and Technology ◽

10.5254/1.3540186 ◽

1961 ◽

Vol 34 (1) ◽

pp. 165-175 ◽

Cited By ~ 1

Author(s):

A. A. Trapeznikov

Keyword(s):

Polymer Solutions ◽

Coaxial Cylinder ◽

Moment Of Inertia ◽

Colloidal Systems ◽

Elastic Recoil ◽

Elastic Deformations ◽

Yield Value ◽

New Instrument ◽

Colloidal Gel ◽

Minimum Moment

Abstract 1. A new instrument, the elastorelaxometer (based on the coaxial-cylinder principle) has been developed, for studies of large high-elastic deformations in relaxing colloidal gel systems and polymer solutions. 2. The effects of the following were investigated : a) width of the gap between the cylinders ; b) moment of inertia of the cylinder (with rapidly relaxing colloidal systems, cylinders of the minimum moment of inertia must be used) ; c) nature of the liquid in the bottom of the cylinder ; d) nature of the motion of the inner cylinder at different ultimate deformations. 3. Values of elastic recoil εc for different predetermined deformations ε have been determined in dilute aluminum naphthenate gels in decalin. It is shown that εc passes through a maximum, associated with transition beyond the yield value of the structure, with increase of ε. It is shown that εc can reeah 6000% in 2% gels.

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Pedicle stress shielding following growing rod implantation: case report

Journal of Neurosurgery Spine ◽

10.3171/2018.10.spine18955 ◽

2019 ◽

Vol 30 (5) ◽

pp. 700-704

Author(s):

Daniel J. Cognetti ◽

Amer F. Samdani ◽

Joshua M. Pahys ◽

Mari L. Groves ◽

Steven W. Hwang

Keyword(s):

Case Report ◽

Spinal Column ◽

Stress Shielding ◽

Ct Scans ◽

Skeletally Immature ◽

3D Reconstructions ◽

Severe Scoliosis ◽

Growing Rod ◽

Infantile Idiopathic Scoliosis ◽

Pedicle Morphology

Growing rod surgery for skeletally immature patients helps correct severe scoliosis while allowing continued spinal column growth. Previous reports have studied vertebral body changes following growing rod surgery, but there are currently no published reports on alterations in pedicle morphology. Given the potential need for definitive spinal fusion with pedicle screw instrumentation, an awareness of changes in pedicle morphology is critical. A morphometric analysis of pedicles was performed using 3D reconstructions of 3 CT scans (preoperative and at 3 and 6 years) obtained in a young girl with infantile idiopathic scoliosis (T7 apex) who underwent unilateral rib-to-spine growing rod (2nd–4th ribs to L1) implantation with lengthening every 6 months for 6 years. The pedicle widths on the growing rod side from T5 to T9 (apex ± 2) were all smaller at 6 years postoperatively than preoperatively, while the same-level pedicles opposite the device significantly increased in width. These findings support anecdotal intraoperative reports by surgeons and provide evidence of pedicle stress shielding due to growing rod distraction and force deprivation.

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Curves of Minimum Moment of Inertia with Respect to a Point

Annals of Mathematics ◽

10.2307/1967249 ◽

1906 ◽

Vol 7 (4) ◽

pp. 165 ◽

Cited By ~ 1

Author(s):

Max Mason

Keyword(s):

Moment Of Inertia ◽

Minimum Moment

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Why canines induce resorption of neighboring roots? An imaging correlation

Dental Press Journal of Orthodontics ◽

10.1590/2177-6709.24.1.027-033.oin ◽

2019 ◽

Vol 24 (1) ◽

pp. 27-33

Author(s):

Alberto Consolaro ◽

Omar Hadaya ◽

Taisa Maeshiro Estorce

Keyword(s):

Clinical Management ◽

Clinical Case ◽

Root Resorption ◽

Ct Scans ◽

Imaging Findings ◽

3D Reconstructions

ABSTRACT Despite the explanations about the mechanisms and reasons why dental follicles of unerupted maxillary canines do not cause root resorption in neighboring teeth, questions remain about the time expected for this event and the lack of protocols for preventive clinical management, which may serve as insights for further studies. Here, these mechanisms are correlated with imaging findings of CT scans and 3D reconstructions of a typical clinical case.

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