scholarly journals Stresses in human leg muscles in running and jumping determined by force plate analysis and from published magnetic resonance images.

1998 ◽  
Vol 201 (1) ◽  
pp. 63-70
Author(s):  
S K Thorpe ◽  
Y Li ◽  
R H Crompton ◽  
R M Alexander
Keyword(s):  
Magnetic Resonance ◽  
Human Subjects ◽  
Force Plate ◽  
Magnetic Resonance Images ◽  
Triceps Surae ◽  
Healthy Human ◽  
Cross Sectional ◽  
Leg Muscles ◽  
Magnetic Resonance Imaging Mri ◽  
Plate Analysis

Calculation of the stresses exerted by human muscles requires knowledge of their physiological cross-sectional area (PCSA). Magnetic resonance imaging (MRI) has made it possible to measure PCSAs of leg muscles of healthy human subjects, which are much larger than the PCSAs of cadaveric leg muscles that have been used in previous studies. We have used published MRI data, together with our own force-plate records and films of running and jumping humans, to calculate stresses in the major groups of leg muscles. Peak stresses in the triceps surae ranged from 100 kN m-2 during take off for standing high jumps to 150 kN m-2 during running at 4 m s-1. In the quadriceps, peak stresses ranged from 190 kN m-2 during standing long jumps to 280 kN m-2 during standing high jumps. Similar stresses were calculated from published measurements of joint moments. These stresses are lower than those previously calculated from cadaveric data, but are in the range expected from physiological experiments on isolated muscles.

Association of Cauda Equina Compression on Magnetic Resonance Images and Clinical Signs in Dogs With Degenerative Lumbosacral Stenosis

2002 ◽  
Vol 38 (6) ◽  
pp. 555-562 ◽  
Author(s):  
Philipp D. Mayhew ◽  
Amy S. Kapatkin ◽  
Jeffrey A. Wortman ◽  
Charles H. Vite
Keyword(s):  
Magnetic Resonance ◽  
Cauda Equina ◽  
Clinical Signs ◽  
Magnetic Resonance Images ◽  
Lumbosacral Spine ◽  
Resonance Imaging ◽  
Cross Sectional ◽  
Cauda Equina Compression ◽  
Magnetic Resonance Imaging Mri ◽  
Time Of Presentation

Magnetic resonance imaging (MRI) was used to examine the lumbosacral spine of 27 dogs with degenerative lumbosacral stenosis. Four normal dogs were also similarly imaged. Compression of the soft-tissue structures within the vertebral canal at the lumbosacral space was assessed in two ways: by measuring dorsoventral diameter on T1-weighted sagittal images and cross-sectional area on transverse images. The severity of the clinical signs was compared to the severity of cauda equina compression. No significant correlation was found. It is concluded that degree of compression as determined by MRI at time of presentation is independent of disease severity.

scholarly journals Magnetic resonance imaging template to standardize reporting of anal fistulas

2021 ◽  
Author(s):  
I. Sudoł-Szopińska ◽  
G. A. Santoro ◽  
M. Kołodziejczak ◽  
A. Wiaczek ◽  
U. Grossi
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Treatment Strategies ◽  
Cross Sectional Study ◽  
Resonance Imaging ◽  
Anal Fistulas ◽  
Cross Sectional ◽  
Radiology Reports ◽  
Colorectal Surgeons ◽  
Magnetic Resonance Imaging Mri

AbstractAnal fistula (AF) is a common referral to colorectal surgeons. Management remains challenging and sometimes controversial. Magnetic resonance imaging (MRI) is commonly performed in initial workup for AF. However, reports often lack key information for guiding treatment strategies. It has been shown that with structured radiology reports, there is less missing information. We present a structured MRI template report including 8 key descriptors of anal fistulas, whose effectiveness and acceptability are being assessed in a cross-sectional study (NCT04541238).

scholarly journals Relationship between abnormalities detected by magnetic resonance imaging and knee symptoms in early knee osteoarthritis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Seiya Ota ◽  
Eiji Sasaki ◽  
Shizuka Sasaki ◽  
Daisuke Chiba ◽  
Yuka Kimura ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Knee Osteoarthritis ◽  
Cartilage Damage ◽  
Resonance Imaging ◽  
Mri Findings ◽  
Radiographic Evidence ◽  
Cross Sectional ◽  
Meniscal Lesions ◽  
Magnetic Resonance Imaging Mri

AbstractWe investigated the prevalence of magnetic resonance imaging (MRI) findings and their relationship with knee symptoms in women without radiographic evidence of knee osteoarthritis (KOA). This cross-sectional cohort study included 359 Japanese women without radiographic evidence of KOA (Kellgren‒Lawrence grade < 2). All participants underwent T2-weighted fat-suppressed MRI of their knees. Structural abnormalities (cartilage damage, bone marrow lesions [BMLs], subchondral cysts, bone attrition, osteophytes, meniscal lesions, and synovitis) were scored according to the whole-organ MRI score method. Knee symptoms were evaluated using the Knee Injury and Osteoarthritis Outcome Score. Participants were divided into early and non-KOA groups based on early KOA classification criteria. Logistic regression analysis was performed to evaluate the relationship between MRI abnormalities and knee symptoms. Cartilage damage was the most common abnormality (43.5%). The prevalences of cartilage damage, BMLs, subchondral cysts, bone attrition, meniscal lesions, and synovitis were higher in patients with early KOA than in those without. Synovitis (odds ratio [OR] 2.254, P = 0.002) and meniscal lesions (OR 1.479, P = 0.031) were positively associated with the presence of early KOA. Synovitis was most strongly associated with knee pain and might be a therapeutic target in patients with early KOA.

Effect of Lateral Positioning on Upper Airway Size and Morphology in Sedated Children

2005 ◽  
Vol 103 (3) ◽  
pp. 484-488 ◽  
Author(s):  
Ronald S. Litman ◽  
Nicole Wake ◽  
Lai-Ming Lisa Chan ◽  
Joseph M. McDonough ◽  
Sanghun Sin ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Supine Position ◽  
Upper Airway ◽  
Lateral Position ◽  
Magnetic Resonance Images ◽  
Magnetic Resonance Imaging Examination ◽  
Vocal Cords ◽  
Cross Sectional ◽  
Spontaneously Breathing ◽  
Lateral Positioning

Background Lateral positioning decreases upper airway obstruction in paralyzed, anesthetized adults and in individuals with sleep apnea during sleep. The authors hypothesized that lateral positioning increases upper airway cross-sectional area and total upper airway volume when compared with the supine position in sedated, spontaneously breathing children. Methods Children aged 2-12 yr requiring magnetic resonance imaging examination of the head or neck region using deep sedation with propofol were studied. Exclusion criteria included any type of anatomical or neurologic entity that could influence upper airway shape or size. T1 axial scans of the upper airway were obtained in the supine and lateral positions, with the head and neck axes maintained neutral. Using software based on fuzzy connectedness segmentation (3D-VIEWNIX; Medical Imaging Processing Group, University of Pennsylvania, Philadelphia, PA), the magnetic resonance images were processed and segmented to render a three-dimensional reconstruction of the upper airway. Total airway volumes and cross-sectional areas were computed between the nasal vomer and the vocal cords. Two-way paired t tests were used to compare airway sizes between supine and lateral positions. Results Sixteen of 17 children analyzed had increases in upper airway total volume. The total airway volume (mean +/- SD) was 6.0 +/- 2.9 ml in the supine position and 8.7 +/- 2.5 ml in the lateral position (P &lt; 0.001). All noncartilaginous areas of the upper airway increased in area in the lateral compared with the supine position. The region between the tip of the epiglottis and vocal cords demonstrated the greatest relative percent change. Conclusions The upper airway of a sedated, spontaneously breathing child widens in the lateral position. The region between the tip of the epiglottis and the vocal cords demonstrates the greatest relative percent increase in size.

scholarly journals INDIRECT DECOMPRESSION BY LATERAL FUSION: ANALYSIS OF SAGITAL ALIGNMENT

2021 ◽  
Vol 20 (1) ◽  
pp. 50-54
Author(s):  
Thyago Guirelle Silva ◽  
Rodrigo Augusto do Amaral ◽  
Raphael Rezende Pratali ◽  
Luiz Pimenta
Keyword(s):  
Magnetic Resonance ◽  
Pelvic Incidence ◽  
Magnetic Resonance Images ◽  
Cross Sectional Area ◽  
Disc Height ◽  
Lower Limbs ◽  
Sectional Area ◽  
Cross Sectional ◽  
Indirect Decompression ◽  
The Mean

ABSTRACT Objective: To verify the effectiveness of indirect decompression after lateral access fusion in patients with high pelvic incidence. Methods: A retrospective, non-comparative, non-randomized analysis of 22 patients with high pelvic incidence who underwent lateral access fusion, 11 of whom were male and 11 female, with a mean age of 63 years (52-74), was conducted. Magnetic resonance exams were performed within one year after surgery. The cross-sectional area of the thecal sac, anterior and posterior disc heights, and bilateral foramen heights, measured pre- and postoperatively in axial and sagittal magnetic resonance images, were analyzed. The sagittal alignment parameters were measured using simple radiographs. The clinical results were evaluated using the ODI and VAS (back and lower limbs) questionnaires. Results: In all cases, the technique was performed successfully without neural complications. The mean cross-sectional area increased from 126.5 mm preoperatively to 174.3 mm postoperatively. The mean anterior disc height increased from 9.4 mm preoperatively to 12.8 mm postoperatively, while the posterior disc height increased from 6.3 mm preoperatively to 8.1 mm postoperatively. The mean height of the right foramen increased from 157.3 mm in the preoperative period to 171.2 mm in the postoperative period and that of the left foramen increased from 139.3 mm in the preoperative to 158.9 mm in the postoperative. Conclusions: This technique is capable of correcting misalignment in spinal deformity, achieving fusion and promoting the decompression of neural elements. Level of evidence III; Retrospective study.

Magnetic resonance imaging studies on autism and childhood-onset schizophrenia in children and adolescents – a review

2003 ◽  
Vol 15 (3) ◽  
pp. 140-147
Author(s):  
Bertine Lahuis ◽  
Chantal Kemner ◽  
Herman Van Engeland
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Children And Adolescents ◽  
Resonance Imaging ◽  
Childhood Onset ◽  
Cross Sectional ◽  
Medline Search ◽  
Childhood Onset Schizophrenia ◽  
Magnetic Resonance Imaging Mri ◽  
Study Designs

Objective:To find out whether the neurodevelopmental disorders autism and childhood-onset schizophrenia have a common developmental pathway and whether the abnormalities detected are ‘disorder-specific’, by reviewing magnetic resonance imaging (MRI) studies.Methods:As a result of a Medline search, we were able to access 28 studies on autism and 12 studies on childhood-onset schizophrenia, which focused on children and adolescents.Results:Larger lateral ventricles were found to be a common abnormality in both disorders. ‘Disorder-specific’ abnormalities in patients with autism were larger brains, a larger thalamic area, and a smaller right cingulate gyrus. Subjects with childhood-onset schizophrenia were found to have smaller brains, a smaller amygdalum and thalamus, and a larger nucleus caudatus. In subjects with childhood-onset schizophrenia, abnormalities appeared to progress over a limited period of time.Conclusions:Because the study designs varied so much, the results should be interpreted cautiously. Before abnormalities found in the disorders can be designated as equal or ‘disorder-specific’, it will be essential to perform large longitudinal and cross-sectional follow-up studies.

Nasal airway geometry: comparison between acoustic reflections and magnetic resonance scanning

1993 ◽  
Vol 75 (6) ◽  
pp. 2811-2819 ◽  
Author(s):  
O. Hilberg ◽  
F. T. Jensen ◽  
O. F. Pedersen
Keyword(s):  
Magnetic Resonance ◽  
Nasal Cavity ◽  
Posterior Part ◽  
Interindividual Variation ◽  
Acoustic Measurements ◽  
Cross Sectional ◽  
Acoustic Reflection ◽  
Magnetic Resonance Imaging Mri ◽  
Magnetic Resonance Scanning

To evaluate the accuracy of the acoustic reflection (AR) technique for determination of nasal cavity cross-sectional areas, the area-distance function of both sides of the nose was determined in 10 subjects and compared with magnetic resonance imaging (MRI). Interindividual variation for the correlation between MRI and AR was seen, but in general the areas from 1 to 6 cm into the nasal cavity measured by AR were larger than areas measured by MRI, especially where the surface was most convoluted. The total volume for this region was 6.47 +/- 1.83 (SD) cm3 for AR and 5.65 +/- 1.34 cm3 for MRI. It was demonstrated that this could be due to errors in calculation of the areas on the basis of MRI and AR. In the posterior part of the nasal cavity and the epipharynx, there was a convincingly higher correlation between acoustic measurements and a scan perpendicular to the assumed geometrical axis of the epipharynx than between acoustic measurements and coronal scanning. This indicates that the sound axis roughly follows the geometrical axis. In a model of two tubes (nasal cavities) joined in a larger tube (the epipharynx), closure of the posterior part of the latter revealed that the contralateral nasal cavity is likely to cause overestimation of the posterior part of the epipharynx during AR compared with MRI.

scholarly journals Universality in human cortical folding in health and disease

2016 ◽  
Vol 113 (45) ◽  
pp. 12820-12825 ◽  
Author(s):  
Yujiang Wang ◽  
Joe Necus ◽  
Marcus Kaiser ◽  
Bruno Mota
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Human Subjects ◽  
Scaling Law ◽  
Age Groups ◽  
Single Species ◽  
Magnetic Resonance Images ◽  
Common Mechanism ◽  
Cortical Folding ◽  
Healthy Human

The folding of the cortex in mammalian brains across species has recently been shown to follow a universal scaling law that can be derived from a simple physics model. However, it was yet to be determined whether this law also applies to the morphological diversity of different individuals in a single species, in particular with respect to factors, such as age, sex, and disease. To this end, we derived and investigated the cortical morphology from magnetic resonance images (MRIs) of over 1,000 healthy human subjects from three independent public databases. Our results show that all three MRI datasets follow the scaling law obtained from the comparative neuroanatomical data, which strengthens the case for the existence of a common mechanism for cortical folding. Additionally, for comparable age groups, both male and female brains scale in exactly the same way, despite systematic differences in size and folding. Furthermore, age introduces a systematic shift in the offset of the scaling law. In the model, this shift can be interpreted as changes in the mechanical forces acting on the cortex. We also applied this analysis to a dataset derived from comparable cohorts of Alzheimer’s disease patients and healthy subjects of similar age. We show a systematically lower offset and a possible change in the exponent for Alzheimer’s disease subjects compared with the control cohort. Finally, we discuss implications of the changes in offset and exponent in the data and relate it to existing literature. We, thus, provide a possible mechanistic link between previously independent observations.

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