Relationship between axial motion and volume displacement of the diaphragm during VC maneuvers

1992 ◽  
Vol 72 (4) ◽  
pp. 1536-1540 ◽  
Author(s):  
J. A. Verschakelen ◽  
K. Deschepper ◽  
M. Demedts
Keyword(s):  
Theoretical Analysis ◽  
Linear Relationship ◽  
Vital Capacity ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Axial Motion ◽  
Cross Sectional ◽  
Good Linear ◽  
Good Linear Relationship ◽  
The Mean

During semistatic inspiratory and expiratory vital capacity (VC) maneuvers, axial motion of the diaphragm was measured by lateral fluoroscopy and was compared with diaphragmatic volume displacement. Axial motion was measured at the anterior, middle, and posterior parts of the diaphragm, and the mean of these measurements was used. The volume displacement was calculated in two ways: first, from respiratory inductive plethysmograph-(Respitrace) derived cross-sectional area changes of rib cage and abdomen (Vdi,RIP) by means of a theoretical analysis described by Mead and Loring (J. Appl. Physiol. 53: 750–755, 1982) and, second, from fluoroscopically measured changes in position and anteroposterior surface of the diaphragm (Vdi,F). A very good linear relationship was found between Vdi,RIP and Vdi,F during inspiration as well as expiration (r greater than 0.95), indicating that the analysis of Mead and Loring was valid in the conditions of the present study. The diaphragmatic volume displacement (active or passive) accounted for 50–60% of VC. A very good linear relationship was also found between mean axial motion and volume displacement of the diaphragm measured with both methods during inspiration and expiration (r greater than 0.98). Our data suggest that, over the VC range, diaphragmatic displacement functionally can be represented by a pistonlike model, although topographically and anatomically it does not behave as a piston.

scholarly journals Atrophy patterns in isolated subscapularis lesions

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Gernot Seppel ◽  
Andreas Voss ◽  
Daniel J. H. Henderson ◽  
Simone Waldt ◽  
Bernhard Haller ◽  
...  
Keyword(s):  
Muscle Atrophy ◽  
Area Ratio ◽  
Cross Sectional Area ◽  
Control Group ◽  
Sectional Area ◽  
Cross Sectional ◽  
Subscapularis Muscle ◽  
Mri Scans ◽  
The Mean ◽  
The Cross

Abstract Background While supraspinatus atrophy can be described according to the system of Zanetti or Thomazeau there is still a lack of characterization of isolated subscapularis muscle atrophy. The aim of this study was to describe patterns of muscle atrophy following repair of isolated subscapularis (SSC) tendon. Methods Forty-nine control shoulder MRI scans, without rotator cuff pathology, atrophy or fatty infiltration, were prospectively evaluated and subscapularis diameters as well as cross sectional areas (complete and upper half) were assessed in a standardized oblique sagittal plane. Calculation of the ratio between the upper half of the cross sectional area (CSA) and the total CSA was performed. Eleven MRI scans of patients with subscapularis atrophy following isolated subscapularis tendon tears were analysed and cross sectional area ratio (upper half /total) determined. To guarantee reliable measurement of the CSA and its ratio, bony landmarks were also defined. All parameters were statistically compared for inter-rater reliability, reproducibility and capacity to quantify subscapularis atrophy. Results The mean age in the control group was 49.7 years (± 15.0). The mean cross sectional area (CSA) was 2367.0 mm2 (± 741.4) for the complete subscapularis muscle and 1048.2 mm2 (± 313.3) for the upper half, giving a mean ratio of 0.446 (± 0.046). In the subscapularis repair group the mean age was 56.7 years (± 9.3). With a mean cross sectional area of 1554.7 mm2 (± 419.9) for the complete and of 422.9 mm2 (± 173.6) for the upper half of the subscapularis muscle, giving a mean CSA ratio of 0.269 (± 0.065) which was seen to be significantly lower than that of the control group (p < 0.05). Conclusion Analysis of typical atrophy patterns of the subscapularis muscle demonstrates that the CSA ratio represents a reliable and reproducible assessment tool in quantifying subscapularis atrophy. We propose the classification of subscapularis atrophy as Stage I (mild atrophy) in case of reduction of the cross sectional area ratio < 0.4, Stage II (moderate atrophy) in case of < 0.35 and Stage III (severe atrophy) if < 0.3.

scholarly journals The influence of muscle pennation angle and cross-sectional area on contact forces in the ankle joint

2016 ◽  
Vol 52 (1) ◽  
pp. 12-23 ◽  
Author(s):  
Ran S Sopher ◽  
Andrew A Amis ◽  
D Ceri Davies ◽  
Jonathan RT Jeffers
Keyword(s):  
Pennation Angle ◽  
Muscle Architecture ◽  
Cross Sectional Area ◽  
Contact Forces ◽  
Sectional Area ◽  
Muscle Forces ◽  
Cross Sectional ◽  
Contact Loads ◽  
The Mean ◽  
And Function

Data about a muscle’s fibre pennation angle and physiological cross-sectional area are used in musculoskeletal modelling to estimate muscle forces, which are used to calculate joint contact forces. For the leg, muscle architecture data are derived from studies that measured pennation angle at the muscle surface, but not deep within it. Musculoskeletal models developed to estimate joint contact loads have usually been based on the mean values of pennation angle and physiological cross-sectional area. Therefore, the first aim of this study was to investigate differences between superficial and deep pennation angles within each muscle acting over the ankle and predict how differences may influence muscle forces calculated in musculoskeletal modelling. The second aim was to investigate how inter-subject variability in physiological cross-sectional area and pennation angle affects calculated ankle contact forces. Eight cadaveric legs were dissected to excise the muscles acting over the ankle. The mean surface and deep pennation angles, fibre length and physiological cross-sectional area were measured. Cluster analysis was applied to group the muscles according to their architectural characteristics. A previously validated OpenSim model was used to estimate ankle muscle forces and contact loads using architecture data from all eight limbs. The mean surface pennation angle for soleus was significantly greater (54%) than the mean deep pennation angle. Cluster analysis revealed three groups of muscles with similar architecture and function: deep plantarflexors and peroneals, superficial plantarflexors and dorsiflexors. Peak ankle contact force was predicted to occur before toe-off, with magnitude greater than five times bodyweight. Inter-specimen variability in contact force was smallest at peak force. These findings will help improve the development of experimental and computational musculoskeletal models by providing data to estimate force based on both surface and deep pennation angles. Inter-subject variability in muscle architecture affected ankle muscle and contact loads only slightly. The link between muscle architecture and function contributes to the understanding of the relationship between muscle structure and function.

A computed method for noninvasive MRI assessment of pulmonary arterial hypertension

2004 ◽  
Vol 96 (2) ◽  
pp. 463-468 ◽  
Author(s):  
Eric Laffon ◽  
Christophe Vallet ◽  
Virginie Bernard ◽  
Michel Montaudon ◽  
Dominique Ducassou ◽  
...  
Keyword(s):  
Arterial Pressure ◽  
Pulmonary Arterial Pressure ◽  
Cross Sectional Area ◽  
Physical Parameters ◽  
Sectional Area ◽  
Biophysical Parameters ◽  
Cross Sectional ◽  
Mean Pulmonary Arterial Pressure ◽  
Pulmonary Arterial ◽  
The Mean

The present method enables the noninvasive assessment of mean pulmonary arterial pressure from magnetic resonance phase mapping by computing both physical and biophysical parameters. The physical parameters include the mean blood flow velocity over the cross-sectional area of the main pulmonary artery (MPA) at the systolic peak and the maximal systolic MPA cross-sectional area value, whereas the biophysical parameters are related to each patient, such as height, weight, and heart rate. These parameters have been measured in a series of 31 patients undergoing right-side heart catheterization, and the computed mean pulmonary arterial pressure value (PpaComp) has been compared with the mean pressure value obtained from catheterization (PpaCat) in each patient. A significant correlation was found that did not differ from the identity line PpaComp = PpaCat ( r = 0.92). The mean and maximal absolute differences between PpaComp and PpaCat were 5.4 and 11.9 mmHg, respectively. The method was also applied to compute the MPA systolic and diastolic pressures in the same patient series. We conclude that this computed method, which combines physical (whoever the patient) and biophysical parameters (related to each patient), improves the accuracy of MRI to noninvasively estimate pulmonary arterial pressures.

scholarly journals Patients with Achilles Tendon Rupture Have a Degenerated Contralateral Achilles Tendon: An Elastography Study

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Qianru Li ◽  
Qi Zhang ◽  
Yehua Cai ◽  
Yinghui Hua
Keyword(s):  
Achilles Tendon ◽  
Axial Strain ◽  
Achilles Tendon Rupture ◽  
Cross Sectional Area ◽  
Control Group ◽  
Computer Assisted ◽  
Study Group ◽  
Sectional Area ◽  
Cross Sectional ◽  
The Mean

Purpose. To evaluate differences of Achilles tendon (AT) hardness and morphology between asymptomatic tendons in patients with acute AT ruptures on the contralateral side and asymptomatic tendons in healthy people by using computer-assisted quantification on axial-strain sonoelastography (ASE). Methods. The study consisted of 33 asymptomatic tendons in 33 patients (study group) and 34 tendons in 19 healthy volunteers (control group). All the tendons were examined by both ASE and conventional ultrasound. Computer-assisted quantification on ASE was applied to extract hardness variables, including the mean (Hmean), 20th percentile (H20), median (H50) and skewness (Hsk) of the hardness within tendon, and the ratio of the mean hardness within tendon to that outside tendon (Hratio) and three morphological variables: the thickness (THK), cross-sectional area, and eccentricity (ECC) of tendons. Results. The Hmean, Hsk, H20, H50, and Hratio in the proximal third of the tendon body in study group were significantly smaller than those in control group (Hmean: 0.43±0.09 vs 0.50±0.07, p=0.001; Hsk: -0.53±0.51 vs -1.09±0.51, p<0.001; H20: 0.31±0.10 vs 0.40±0.10, p=0.001; H50: 0.45±0.10 vs 0.53±0.08, p<0.001; Hratio: 1.01±0.25 vs 1.20±0.23, p=0.003). The THK and cross-sectional area of tendons in the study group were larger than those in the control group (p<0.05). Conclusions. As a quantitative objective method, the computer-assisted ASE reveals that the asymptomatic ATs contralateral to acute rupture are softer than those of healthy control group at the proximal third and the asymptomatic tendons in people with rupture history are thicker, larger, and rounder than those of normal volunteers especially at the middle and distal thirds of AT body.

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.

scholarly journals The Nonlinear Relationship Between Psoas Cross-sectional Area and BMI: A New Observation and Its Insights into Diabetes Remission After Roux-en-Y Gastric Bypass

2021 ◽  
Author(s):  
Shaobo Li ◽  
Haoyong Yu ◽  
Pin Zhang ◽  
Yinfang Tu ◽  
Yunfeng Xiao ◽  
...  
Keyword(s):  
Gastric Bypass ◽  
Linear Relationship ◽  
Muscle Mass ◽  
Diabetes Remission ◽  
Cross Sectional Area ◽  
Fat Free Mass ◽  
Sectional Area ◽  
Cross Sectional ◽  
Non Linear ◽  
Design And Methods

OBJECTIVE <p>To<a> explore the potential relevance of muscle mass as a variable contributor to body mass index (BMI) on BMI limitations in predicting diabetes remission (DR) after Roux-en-Y gastric bypass (RYGB). </a></p> <p> </p> <p>RESEARCH DESIGN AND METHODS</p> <p>We evaluated the relationship between muscle mass and BMI in 501 patients with type 2 diabetes mellitus and overweight or obesity. Of which <a>186 patients who underwent R</a>YGB were <a>studied to determine the role of baseline muscle mass </a><a>and BMI </a>in predicting DR. Muscle mass was assessed by estimated fat-free mass index (eFFMI) and psoas cross-sectional area (CSA).</p> <p> </p> <p>RESULTS</p> <p>A non-linear relationship existed between psoas CSA and BMI, whereas psoas CSA showed a highly positive correlation with <a>eFFMI</a>. Baseline psoas CSA and eFFMI were better than BMI for predicting 1- and 5-year DR. </p> <p> </p> <p>CONCLUSIONS</p> <p><a>The </a><a>non-linear relationship between</a> muscle mass and BMI may <a>partially contribute to </a><a>BMI limitations in predicting DR</a> after RYGB. </p>

The Vertical Mean Force and Moment of Submerged Bodies Under Waves

1971 ◽  
Vol 15 (03) ◽  
pp. 231-245 ◽  
Author(s):  
C. M. Lee ◽  
J. N. Newman
Keyword(s):  
Free Surface ◽  
Added Mass ◽  
Cross Sectional Area ◽  
The Body ◽  
Slender Body ◽  
Longitudinal Distribution ◽  
Vertical Force ◽  
Sectional Area ◽  
Cross Sectional ◽  
The Mean

A neutrally buoyant slender body of arbitrary sectional form, submerged beneath a free surface, is free to respond to an incident plane progressive wave system. The fluid is assumed inviscid, incompressible, homogeneous and infinitely deep. The first-order oscillatory motion of the body and the second-order time-average vertical force and pitching moment acting on the body are obtained in terms of Kochin's function. By use of slender-body theory for a deeply submerged body, the final expressions for the mean force and the moment are shown to depend on the longitudinal distribution of sectional area and added mass and on the amplitude and the frequency of the ambient surface waves. The magnitude of the mean force for various simple geometric cylinders is compared with that of a circular cylinder of equal cross-sectional area. The mean force on a nonaxisymmetric body is often approximated by replacing the section with circular profiles of equivalent cross-sectional area. A better scheme of approximation is presented, based on a simple way of estimating the two-dimensional added mass. It is expected that the effect of the cross-sectional geometry on mean vertical force and moment will be more significant when the body is very close to the free surface.

Treatment of Acute Focal Cerebral Ischemia with Intermittent, Low Dose Mannitol

Neurosurgery ◽  
1979 ◽  
Vol 5 (6) ◽  
pp. 687-691 ◽  
Author(s):  
John R. Little
Keyword(s):  
Low Dose ◽  
Cross Sectional Area ◽  
Cerebral Injury ◽  
Left Middle Cerebral Artery ◽  
Sodium Pentobarbital ◽  
Sectional Area ◽  
Cross Sectional ◽  
Luminal Diameter ◽  
Mca Occlusion ◽  
The Mean

Abstract The object of this investigation was to study the effects of intermittent, low dose mannitol therapy on conscious cats after acute left middle cerebral artery (MCA) occlusion. A simple implanted device was applied to the proximal left MCA of 40 adult cats using microsurgical techniques. In the acute experiments, 10 cats were untreated and 10 cats received mannitol (0.5 g/kg intravenously) immediately before occlusion and again 3, 6, and 9 hours later. They subsequently underwent intra-arterial perfusion with colloidal carbon and buffered paraformaldehyde 12 hours after occlusion. The plasma osmolality immediately before perfusion was 316 ± 2 (SD) milliosmoles in untreated cats and 331 ± 5 milliosmoles in treated cats. Gross swelling, impaired carbon filling, and breakdown of the blood-brain barrier (BBB) to fluorescein were seen in the left MCA territory of 8 untreated cats and 1 treated cat. The mean percentage of gray matter cross sectional area where severe ischemic neuronal alterations predominated was 45 ± 12% in untreated and 14 ± 16% in treated cats (p &lt; 0.01). The mean capillary luminal diameter in the left sylvian cortex was 4.5 ± 1.0 μ in untreated cats (control, 6.5 ± 1.0 μ) and 5.5 ± 1.0 μ in treated cats. In the subacute experiments, 10 cats were not treated and 10 cats received mannitol as in the acute experiments. The cats were killed with a large bolus of sodium pentobarbital 48 hours after left MCA occlusion. Gross swelling and breakdown of the BBB were less severe in treated cats. The mean cross sectional area of infarcted tissue was 55 ± 12% in untreated cats and 33 ± 21% in treated cats (p &lt; 1.0). The findings of this study indicate that intermittent, low dose mannitol therapy delays the onset of ischemic cerebral injury and may reduce the size of the eventual infarct or convert a potential infarct into a so-called “transient ischemic attack.”

scholarly journals A comparison of minimal cross sectional areas, nasal volumes and peak nasal inspiratory flow between patients with obstructive sleep apnea and healthy controls

2016 ◽  
Vol 54 (4) ◽  
pp. 342-347
Author(s):  
M.H.S. Moxness ◽  
V. Bugten ◽  
W.M. Thorstensen ◽  
S. Nordgard ◽  
G. Bruskeland
Keyword(s):  
Nasal Cavity ◽  
Inspiratory Flow ◽  
Cross Sectional Area ◽  
Healthy Controls ◽  
Sectional Area ◽  
Cavity Volume ◽  
Cross Sectional ◽  
The Mean ◽  
And Function ◽  
Peak Nasal Inspiratory Flow

Background: The differences in nasal geometry and function between OSA patients and healthy individuals are not known. Our aim was to evaluate the differences in nasal geometry and function using acoustic rhinometry (AR) and peak nasal inspiratory flow (PNIF) between an OSA population and healthy controls. Methodology: The study was designed as a prospective case-control study. Ninety-three OSA patients and 92 controls were enrolled from 2010 to 2015. The minimal cross-sectional area (MCA) and the nasal cavity volume (NCV) in two parts of the nose (MCA0-3/NCV0-3 and MCA3-5.2/NCV3-5.2) and PNIF were measured at baseline and after decongestion. Results: The mean MCA0-3 in the OSA group was 0.49 cm2; compared to 0.55 cm2 in controls. The mean NCV0-3 correspondingly was 2.51 cm3 compared to 2.73 cm3 in controls. PNIF measured 105 litres/minute in the OSA group and 117 litres/minute in the controls. Conclusions: OSA patients have a lower minimum cross-sectional area, nasal cavity volume and peak inspiratory flow compared to controls. Our study supports the view that changes in the nasal cavity may contribute to development of OSA.

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