Investigation of Geometric Deformations of The Lumbar Disc During Axial Body Rotations

Abstract BackgroundQuantitative data on in vivo vertebral disc deformations are critical for enhancing our understanding of spinal pathology and improving the design of surgical materials. This study investigated in vivo lumbar intervertebral disc deformations during axial rotations under different load-bearing conditions.MethodsTwelve healthy subjects (7 males and 5 females) between the ages of 25 and 39 were recruited. Using a combination of a dual fluoroscopic imaging system (DFIS) and CT, the images of L3-5 segments scanned by CT were transformed into three-dimensional models, which matched the instantaneous images of the lumbar spine taken by a double fluorescent X-ray system during axial rotations to reproduce motions. Then, the kinematic data of the compression and shear deformations of the lumbar disc and the coupled bending of the vertebral body were obtained.ResultsRelative to the supine position, the average compression deformation caused by rotation is between +10% and -40%, and the shear deformation is between 17% and 50%. Under physiological weightbearing loads, different levels of lumbar discs exhibit similar deformation patterns, and the deformation patterns of left and right rotations are approximately symmetrical. The deformation patterns change significantly under a 10 kg load, with the exception of the L3-4 disc during the right rotation.ConclusionThe deformation of the lumbar disc was direction-specific and level-specific during axial rotations and was affected by extra weight. These data can provide new insights into the biomechanics of the lumbar spine and optimize the parameters of artificial lumbar spine devices.

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Ranges of Cervical Intervertebral Disc Deformation During an In Vivo Dynamic Flexion–Extension of the Neck

Journal of Biomechanical Engineering ◽

10.1115/1.4036311 ◽

2017 ◽

Vol 139 (6) ◽

Cited By ~ 3

Author(s):

Yan Yu ◽

Haiqing Mao ◽

Jing-Sheng Li ◽

Tsung-Yuan Tsai ◽

Liming Cheng ◽

...

Keyword(s):

Cervical Spine ◽

Imaging System ◽

Human Subjects ◽

Three Dimensional ◽

Cervical Disc ◽

Significant Difference ◽

Flexion Extension ◽

Fluoroscopic Imaging ◽

Magnetic Resonance Imaging Mri

While abnormal loading is widely believed to cause cervical spine disc diseases, in vivo cervical disc deformation during dynamic neck motion has not been well delineated. This study investigated the range of cervical disc deformation during an in vivo functional flexion–extension of the neck. Ten asymptomatic human subjects were tested using a combined dual fluoroscopic imaging system (DFIS) and magnetic resonance imaging (MRI)-based three-dimensional (3D) modeling technique. Overall disc deformation was determined using the changes of the space geometry between upper and lower endplates of each intervertebral segment (C3/4, C4/5, C5/6, and C6/7). Five points (anterior, center, posterior, left, and right) of each disc were analyzed to examine the disc deformation distributions. The data indicated that between the functional maximum flexion and extension of the neck, the anterior points of the discs experienced large changes of distraction/compression deformation and shear deformation. The higher level discs experienced higher ranges of disc deformation. No significant difference was found in deformation ranges at posterior points of all the discs. The data indicated that the range of disc deformation is disc level dependent and the anterior region experienced larger changes of deformation than the center and posterior regions, except for the C6/7 disc. The data obtained from this study could serve as baseline knowledge for the understanding of the cervical spine disc biomechanics and for investigation of the biomechanical etiology of disc diseases. These data could also provide insights for development of motion preservation surgeries for cervical spine.

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In Vivo Lumbar Intervertebral Disc Deformation During Lateral Bending Motion Under Different Load-Bearing Conditions

10.21203/rs.3.rs-423428/v1 ◽

2021 ◽

Author(s):

Haoxiang Xu ◽

Wangqiang Wen ◽

Zepei Zhang ◽

Bowen Kou ◽

Jincheng Wu ◽

...

Keyword(s):

Lumbar Spine ◽

Intervertebral Disc ◽

Tensile Deformation ◽

Lumbar Disc ◽

Lateral Bending ◽

Lumbar Intervertebral Disc ◽

Load Bearing ◽

Compression Deformation ◽

Left And Right

Abstract Background Lumbar Intervertebral Disc Degeneration (LDD) is one of the largest health worldwide problems, based on lost working time and associated costs. Inappropriate mechanical loading is considered to be an important factor in the development of LDD. L3-4 and L4-L5 were the commonly affected levels. Recent studies have measured geometric deformation of lumbar intervertebral discs during an in vivo functional weightbearing of the lumbar. The purpose of the present study was to determine the lumbar disc deformation in living human subjects during lateral bending motion under different load-bearing conditions. Methods 11 healthy subjects, 6 males and 5 females, aged 21 ≤ 39 years, with an average age of 30 ± 5 years, were recruited for the present study. Using the combination of dual fluoroscopic imaging system(DFIS)and CT, the sagittal images of L3-5 segments scanned by CT were transformed into three-dimensional reconstruction models and then matched to the instantaneous images of lumbar spine motion taken by a double fluorescent X-ray system under different loads. Motions were reproduced with the use of the combined imaging technique during left and right bending movements. Then, the kinematics data of the height, tension and compression deformation, and shear deformation of the lumbar intervertebral disc were obtained by using computer-related software. Result The data indicated that the tendency of tensile deformation during left and right bending was approximately symmetric. During the functional bending of the body, there was a greater compression deformation behind the same side of the movement and a higher tension deformation in front of the contralateral movement. The magnitude changed along the diagonal towards the posterolateral direction. During left bending, the upper vertebrae had a larger deformation range and tension deformation than the lower vertebrae. Meanwhile, it was not found that the small load had a significant effect on the tensile deformation of the intervertebral disc. Conclusion Lumbar disc deformation showed direction-specific and level-specific changes during lateral bending motion. These results could help understand the physiological motion characters of the lumbar spine and provide data support for other biomechanical studies.

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Alteration within the Hippocampal Volume in Patients with LHON Disease—7 Tesla MRI Study

Journal of Clinical Medicine ◽

10.3390/jcm10010014 ◽

2020 ◽

Vol 10 (1) ◽

pp. 14

Author(s):

Cezary Grochowski ◽

Kamil Jonak ◽

Marcin Maciejewski ◽

Andrzej Stępniewski ◽

Mansur Rahnama-Hezavah

Keyword(s):

Magnetic Resonance Imaging ◽

Magnetic Resonance ◽

Molecular Layer ◽

Three Dimensional ◽

Hippocampal Volume ◽

7 Tesla ◽

Diagnostic Process ◽

Resonance Imaging ◽

The Right

Purpose: The aim of this study was to assess the volumetry of the hippocampus in the Leber’s hereditary optic neuropathy (LHON) of blind patients. Methods: A total of 25 patients with LHON were randomly included into the study from the national health database. A total of 15 patients were selected according to the inclusion criteria. The submillimeter segmentation of the hippocampus was based on three-dimensional spoiled gradient recalled acquisition in steady state (3D-SPGR) BRAVO 7T magnetic resonance imaging (MRI) protocol. Results: Statistical analysis revealed that compared to healthy controls (HC), LHON subjects had multiple significant differences only in the right hippocampus, including a significantly higher volume of hippocampal tail (p = 0.009), subiculum body (p = 0.018), CA1 body (p = 0.002), hippocampal fissure (p = 0.046), molecular layer hippocampus (HP) body (p = 0.014), CA3 body (p = 0.006), Granule Cell (GC) and Molecular Layer (ML) of the Dentate Gyrus (DG)–GC ML DG body (p = 0.003), CA4 body (p = 0.001), whole hippocampal body (p = 0.018), and the whole hippocampus volume (p = 0.023). Discussion: The ultra-high-field magnetic resonance imaging allowed hippocampus quality visualization and analysis, serving as a powerful in vivo diagnostic tool in the diagnostic process and LHON disease course assessment. The study confirmed previous reports regarding volumetry of hippocampus in blind individuals.

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Three-dimensional distribution of CT attenuation in the lumbar spine pedicle wall

Scientific Reports ◽

10.1038/s41598-020-80676-5 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Tomoyo Y. Irie ◽

Tohru Irie ◽

Alejandro A. Espinoza Orías ◽

Kazuyuki Segami ◽

Norimasa Iwasaki ◽

...

Keyword(s):

Lumbar Spine ◽

Age Groups ◽

Three Dimensional ◽

Hounsfield Unit ◽

Lateral Wall ◽

Ct Attenuation ◽

Dimensional Distribution ◽

The Mean ◽

Pedicle Wall

AbstractThis study investigated in vivo the three-dimensional distribution of CT attenuation in the lumbar spine pedicle wall measured in Hounsfield Unit (HU). Seventy-five volunteers underwent clinical lumbar spine CT scans. Data was analyzed with custom-written software to determine the regional variation in pedicle wall attenuation values. A cylindrical coordinate system oriented along the pedicle’s long axis was used to calculate the pedicular wall attenuation distribution three-dimensionally and the highest attenuation value was identified. The pedicular cross-section was divided into four quadrants: lateral, medial, cranial, and caudal. The mean HU value for each quadrant was calculated for all lumbar spine levels (L1–5). The pedicle wall attenuation was analyzed by gender, age, spinal levels and anatomical quadrant. The mean HU values of the pedicle wall at L1 and L5 were significantly lower than the values between L2–4 in both genders and in both age groups. Furthermore, the medial quadrant showed higher HU values than the lateral quadrant at all levels and the caudal quadrant showed higher HU values at L1–3 and lower HU values at L4–5 than the cranial quadrant. These findings may explain why there is a higher incidence of pedicle screw breach in the pedicle lateral wall.

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ECG-gated dynamic magnetic resonance imaging method for examination of the pig heart

Acta Veterinaria Hungarica ◽

10.1556/004.49.2001.3.3 ◽

2001 ◽

Vol 49 (3) ◽

pp. 275-284

Author(s):

Zs. Petrási ◽

R. Romvári ◽

G. Bajzik ◽

B. Fenyves ◽

I. Repa ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Magnetic Resonance ◽

Three Dimensional ◽

Dynamic Magnetic Resonance Imaging ◽

Imaging Method ◽

Resonance Imaging ◽

Dynamic Magnetic Resonance ◽

Heart Cycle ◽

The Right

A dynamic magnetic resonance imaging (MRI) method was developed for in vivo examination of the pig heart. Measurements were carried out on 15 meat-type pigs of different liveweight using a 1.5 T equipment. Inhalation anaesthesia was applied, then data acquisition was synchronised by ECG gating. Depending on the heart rate and heart size, in each case 8 to 10 slices and in each slice 8 to 14 phases were acquired prospectively according to one heart cycle. During the post-processing of the images the left and the right ventricular volumes were determined. The values measured at 106 kg liveweight are 2.5 times higher than those obtained at 22 kg, while the ejection fractions are equal. The calculated cardiac output values were 3.5 l (22 kg, 132 beats/min.), and 6.0 l (106 kg, 91 beats/min.), respectively. After measuring the wall thickness, the contraction values were also determined for the septum (70%), and for the anterior (61%), posterior (41%) and lateral (54%) walls of the left ventricle. Three-dimensional animated models of the ventricles were constructed. Based on the investigations performed, the preconditioning, the anaesthetic procedure, the specific details of ECG measurement and the correct MR imaging technique were worked out.

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Dual-Energy CT–based Phantomless in Vivo Three-dimensional Bone Mineral Density Assessment of the Lumbar Spine

Radiology ◽

10.1148/radiol.13131952 ◽

2014 ◽

Vol 271 (3) ◽

pp. 778-784 ◽

Cited By ~ 35

Author(s):

Julian L. Wichmann ◽

Christian Booz ◽

Stefan Wesarg ◽

Konstantinos Kafchitsas ◽

Ralf W. Bauer ◽

...

Keyword(s):

Bone Mineral Density ◽

Lumbar Spine ◽

Bone Mineral ◽

Three Dimensional ◽

Dual Energy ◽

Dual Energy Ct ◽

Mineral Density ◽

Bone Mineral Density Assessment ◽

Density Assessment

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Making Anaglyphs in Photoshop

Microscopy Today ◽

10.1017/s1551929500051622 ◽

2005 ◽

Vol 13 (3) ◽

pp. 36-39 ◽

Cited By ~ 1

Author(s):

Jerry Sedgewick

Keyword(s):

Imaging System ◽

Three Dimensional ◽

Ct Scans ◽

Two Dimensional ◽

The Right ◽

Two Dimensional Images

In order to achieve a three dimensional appearance to a pair of two dimensional images, two off-axis images can be produced and colorized. These can be overlayed slightly apart and then viewed through glasses with two differently colored sides, one color for the left eye and another for the right eye in combinations containing red, green or blue colors. These off-axis and colorized images are referred to as anaglyphs.Off-axis images can be achieved through the use of a tilting stage on a microscope, by physically changing the position of a camera in relation to a still object, or through changing the axis of an optical stack of sections, such as what is created by confocal/CT scans. Some images lend themselves more to a 3D look both by virtue of inherent three dimensionality limited by the resolution of the imaging system.

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E-wave generated intraventricular diastolic vortex to L-wave relation: model-based prediction with in vivo validation

Journal of Applied Physiology ◽

10.1152/japplphysiol.00215.2014 ◽

2014 ◽

Vol 117 (3) ◽

pp. 316-324 ◽

Cited By ~ 8

Author(s):

Erina Ghosh ◽

Shelton D. Caruthers ◽

Sándor J. Kovács

Keyword(s):

Vortex Ring ◽

Three Dimensional ◽

Direct Consequence ◽

Sample Volume ◽

Transmitral Flow ◽

Suction Pump ◽

Contrast Magnetic Resonance ◽

Intraventricular Flow ◽

The Right

The Doppler echocardiographic E-wave is generated when the left ventricle's suction pump attribute initiates transmitral flow. In some subjects E-waves are accompanied by L-waves, the occurrence of which has been correlated with diastolic dysfunction. The mechanisms for L-wave generation have not been fully elucidated. We propose that the recirculating diastolic intraventricular vortex ring generates L-waves and based on this mechanism, we predict the presence of L-waves in the right ventricle (RV). We imaged intraventricular flow using Doppler echocardiography and phase-contrast magnetic resonance imaging (PC-MRI) in 10 healthy volunteers. L-waves were recorded in all subjects, with highest velocities measured typically 2 cm below the annulus. Fifty-five percent of cardiac cycles (189 of 345) had L-waves. Color M-mode images eliminated mid-diastolic transmitral flow as the cause of the observed L-waves. Three-dimensional intraventricular flow patterns were imaged via PC-MRI and independently validated our hypothesis. Additionally as predicted, L-waves were observed in the RV, by both echocardiography and PC-MRI. The re-entry of the E-wave-generated vortex ring flow through a suitably located echo sample volume can be imaged as the L-wave. These waves are a general feature and a direct consequence of LV and RV diastolic fluid mechanics.

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