Cross-sectional Area Measurements Research Articles

Muscle Ultrasound Changes and Physical Function of Critically Ill Children: A Comparison of Rectus Femoris Cross-Sectional Area and Quadriceps Thickness Measurements.

To compare QT with RFCSA changes, and their association with physical function in critically ill children. Secondary analysis of a prospective cohort study of children 0-18 years old admitted to a tertiary mixed PICU between January 2015 and October 2018 with PICU stay greater than 48 hours and greater than or equal to one organ dysfunction. Ultrasound QT and RFCSA were measured at PICU admission, PICU discharge, hospital discharge, and 6 months post-discharge. QT and RFCSA changes from baseline were compared with each other and with change in motor function, physical ability, and physical health-related quality of life (HRQOL). Two hundred thirty-seven images from 66 subjects were analyzed. RFCSA change was not significantly different from QT change at PICU (-8.07% [interquartile range (IQR), -17.11% to 4.80%] vs -4.55% [IQR, -14.32% to 4.35%]; p = 0.927) or hospital discharge (-5.62% [IQR, -15.00% to 9.42%] vs -8.81% [IQR, -18.67% to 2.39%]; p = 0.238) but was significantly greater than QT change at 6 months (32.7% [IQR, 5.74-109.76%] vs 9.66% [IQR, -8.17% to 25.70%]; p < 0.001). Motor function change at PICU discharge was significantly associated with RFCSA change (adjusted β coefficient, 0.02 [95% CI, 0.01-0.03]; p = 0.013) but not QT change (adjusted β coefficient, -0.01 [95% CI, -0.02 to 0.01]; p = 0.415). Similar results were observed for physical HRQOL changes at hospital discharge (adjusted β coefficient for RFCSA change, 0.51 [95% CI, 0.10-0.92]; p = 0.017 and adjusted β coefficient for QT change, -0.21 [-0.76 to 0.35]; p = 0.458). Physical ability was not significantly associated with RFCSA or QT changes at 6 months post-discharge. Ultrasound derived RFCSA is associated with PICU motor function and hospital discharge physical HRQOL changes, unlike QT, and may be more useful for in-hospital muscle monitoring in critically ill children.

Reliability and validity of assessing lower-limb muscle architecture of patients with cerebral palsy (CP) using ultrasound: A systematic review.

To investigate the reliability, validity, and level of evidence of applying ultrasound in assessing the lower-limb muscles of patients with cerebral palsy (CP). Publications in Medline, PubMed, Web of Science, and Embase were searched on May 10, 2023, to identify and examine relevant studies investigating the reliability/validity of ultrasound in evaluating the architecture of CP lower-limb muscles systematically, following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis 2020 guidelines. Out of 897 records, 9 publications with 111 CP participants aged 3.8-17.0 years were included (8 focused on intra-rater and inter-rater reliability, 2 focused on validity, and 4 were with high quality). The ultrasound-based measurements of muscle thickness (intra-rater only), muscle length, cross-sectional area, muscle volume, fascicle length, and pennation angle showed high reliability, with the majority of intraclass correlation coefficient (ICC) values being larger than 0.9. Moderate-to-good correlations between ultrasound and magnetic resonance imaging measurements existed in muscle thickness and cross-sectional area (0.62 ≤ ICC ≤ 0.82). Generally, ultrasound has high reliability and validity in evaluating the CP muscle architecture, but this is mainly supported by moderate and limited levels of evidence. More high-quality future studies are needed.

Ultrasound of the normal vagus nerve cross-sectional area in the carotid sheath.

The aim of this article is to utilize ultrasound to evaluate the normal cross-sectional area (CSA)of the vagus nerve (VN) in the carotid sheath. This study included 86 VNs in 43 healthy subjects (15 men, 28 women); mean age 42.1 years and mean body mass index 26.2 kg/m2. For each subject, the bilateral VNs were identified by US at the anterolateral neck within the common carotid sheaths. One radiologist obtained 3 separate CSA measurements for each of the bilateral VNs with complete transducer removal between each measurement. Additionally, for each participant, demographic information of age and gender as well as body mass index, weight, and height were documented. The mean CSA of the right VN in the carotid sheath was 2.1 and 1.9 mm2 for the left VN. The right VN CSA was significantly larger than the left VN (P < .012). No statistically significant correlation was noted in relation to height, weight, and age. We believe that the reference values for the normal CSA of the VN obtained in our study, could help in the sonographic evaluation of VN enlargement, as it relates to the diagnosis of various diseases affecting the VN.

Sonographic vagus nerve atrophy in Parkinson's disease: Myth or fact? A systematic review and meta-analysis of recent evidence answers

BackgroundParkinson's disease (PD) is a major cause of disability. We aimed to assess the benefit of ultrasonography of the vagus nerve (VN) to compare between PD and healthy controls as well as to deliver reference values of nerve cross sectional area (CSA). Materials and methodsWe performed a systematic search on Medline (PubMed), Scopus, Embase, and Web of Science, up till July 25, 2022. After article selection and screening, we performed a quality assessment using the Newcastle–Ottawa Scale. Furthermore, a statistical analysis and subgroup analysis was performed. ResultsEleven studies were included with a total of 809 participants (409 PD patients and 400 controls). A statistically significant difference in the CSA of the right and left VN between PD patients and healthy controls was observed, indicating the atrophy of VN in PD patients (p < 0.00001). The subgroup meta-analysis for average measurements of VN CSA showed insignificant heterogeneity for age (I2 = 48.67%, p = 0.058), level of measurements (I2 = 57.91%, p = 0.05), and disease duration (I2 = 27.1%, p = 0.241). ConclusionOur meta-analysis showed a sonographically detectable degree of neuronal damage in PD, which correlates with VN atrophy with high confidence. Therefore, we believe this is a potential marker for vagus neuronal lesions. Future studies are required to assess the potential clinical correlation.

Reproducibility of Femoropopliteal Artery Intravascular Ultrasound Imaging in Patients With Peripheral Artery Disease

Despite increased use of intravascular ultrasound (IVUS) during peripheral artery interventions, evidence for reproducibility of IVUS measurements and its relation to angiography is lacking. Forty cross-sectional IVUS images of the femoropopliteal artery from 20 randomly selected patients enrolled in the XLPAD (Excellence in Peripheral Artery Disease) registry who underwent peripheral artery interventions and met criteria based on IVUS consensus guidelines were independently assessed by 2 blinded readers. IVUS images from 6 patients (40 images) were selected for angiographic correlation and met criteria for identifiable landmarks (e.g., stent edge and bifurcation). Lumen cross-sectional area (CSA), external elastic membrane (EEM) CSA, luminal diameter, and reference vessel diameter were repeatedly measured. The Lumen CSA and EEM CSA intra-observer agreement by Spearman rank-order correlation (ρ) was >0.993, intraclass correlation coefficient was >0.997, and repeatability coefficient was <1.34. For the interobserver measurement of luminal CSA and EEM CSA, the ρ=0.742 and 0.764; intraclass correlation coefficient=0.888 and 0.885; and repeatability coefficient=7.24 and 11.34, respectively. A Bland-Altman plot for lumen and EEM CSA showed good reproducibility. For angiographic comparison, the ρ for luminal diameter, luminal area, and vessel area were 0.419, 0.414, and 0.649, respectively. Femoropopliteal IVUS measurements showed strong intra-observer and interobserver agreement; IVUS and angiographic measurements did not demonstrate a similar strong agreement.

Utilizing a Functional Lumen Imaging Probe for Evaluation of the Pediatric Airway, A Pilot Study.

Accurate and reproducible measurements of the pediatric airway are critical for diagnostic evaluation and management of subglottic and tracheal stenosis. The endoluminal functional lumen imaging probe (EndoFLIP) is a catheter-based imaging probe which utilizes impedance planimetry to calculate luminal parameters, including cross-sectional area and compliance. Herein, we demonstrate the feasibility of this system for multidimensional evaluation of the pediatric airway. 3D-printed pediatric laryngotracheal models were created based on computed tomography scans, then artificially deformed to simulate both circumferential and posterior subglottic stenosis. Two observers made six measurements of the minimum cross-sectional area (MCSA) and length of stenosis of each model with EndoFLIP. Agreement between observer measurements and model dimensions was evaluated using Lin's concordance correlation coefficient; inter-observer reliability was assessed using intraclass correlation. Four models were created: two without pathology (MCSA: 132.4, 44.3 mm2 ) and two with subglottic stenosis (MCSA: 28.7, 59.7 mm2 , stenotic length 27.8, 24.4 mm). Observer measurements of MCSA and length of stenosis demonstrated high concordance with the models (r = 0.99, 0.95, p < 0.001) with a mean error of 4.5% and 18.2% respectively. There was a low coefficient of variation (0.6%-2.8%) for measurements, indicating high precision. Interrater reliability was high for both MCSA and stenotic length (ICC: 0.99, 0.98). The EndoFLIP system allows for accurate and reproducible measurements of cross-sectional area and stenotic length in pediatric airway models. This method may provide further advantages in the evaluation of airway distensibility, as well as measurements of asymmetric airway pathology. NA Laryngoscope, 134:108-112, 2024.

Elementary Liber Fibres Characterisation: Bias from the Noncylindricity and Morphological Evolution along the Fibre

In this work, we investigate the influence of noncircularity along with cross-sectional area evolution on the measurement of the mechanical properties of elementary fibres. First, we focus on the cross-sectional area measurement and compare the circular assumption with the elliptical one using an ombroscopic device that allows the measurement of the projected diameters along the fibre as the fibre rotates around its axis, the fibre dimensional analysis system (FDAS). The results highlight important approximations to the cross-sectional area evaluation for fibres with noncircular cross sections, leading to reduced elastic modulus and stress at failure evaluated by the standard method. Additionally, results from the FDAS are used to evaluate the twist inside an individual fibre when the cross sections are sufficiently elliptical. A numerical model based on the real measured dimensions of the fibres is developed to illustrate and visualize this nonuniformity and to more accurately identify the elastic modulus. The results obtained lead us to an analytical approach that takes into account the evolution of the cross-sectional area along the fibre for a better identification of the stiffness and modulus of elasticity, which maximizes the identified mechanical properties on average by 12% for the modulus and 200% for the stress at failure. Finally, recommendations are formulated to better account for the variability along a fibre in order to evaluate the cross-sectional area.

Nerve Conduction Studies and Measurement of Median Nerve Cross-Sectional Area in Patients Newly Diagnosed with Hypothyroidism

Aim: This study aimed to investigate the rate of carpal tunnel syndrome (CTS) and polyneuropathy in patients with new-diagnosed hypothyroidism and the relationship between median nerve conduction and the cross-sectional area of the median nerve by ultrasonography. Material and Methods: It was a prospective, cross-sectional and case-control study. This study included thirty-five new-diagnosed hypothyroidism cases and thirty-five healthy controls. Bilateral sensory and motor nerve potentials were noted in the lower and upper extremities. The cross-sectional area of the median nerve was examined at the entrance of the CT with the axial plan by ultrasonography. The relationship between the cross-sectional areas of the median nerve and nerve conduction parameters was investigated. Results: CTS was determined electrophysiologically in 8 (22.9%) patients. The control group had no CTS. There was no significant electrophysiological finding to support polyneuropathy in the patients. The cross-sectional areas of the median nerve were higher in the patient group but did not reach statistically significant (p&amp;gt;0.05). There was a positive correlation between the right and left cross-sectional area of median nerves and body mass index (BMI) (p&amp;lt;0.05). Conclusion: The rate of CTS is high in patients with newly diagnosed hypothyroidism. There is a positive correlation between cross-sectional nerve areas and BMI. There was no significant correlation between nerve conductions and median nerve ultrasonographic cross-sectional areas.

Muscle architectural properties indicate a primary role in support for the pelvic limb of three-toed sloths (Bradypus variegatus).

Tree sloths evolved below-branch locomotion making them one of few mammalian taxa beyond primates for which suspension is nearly obligatory. Suspension requires strong limb flexor muscles that provide both propulsion and braking/support, and available locomotor kinetics data indicate that these roles differ between fore- and hindlimb pairs. Muscle structure in the pelvic limb is hypothesized to be a key anatomical correlate of function in braking/support during suspensory walking and propulsion and/or support during vertical climbing. This expectation was tested by quantifying architecture properties in the hindlimb limb musculature of brown-throated three-toed sloths (Bradypus variegatus: N = 7) to distinguish the roles of the flexor/extensor functional muscle groups at each joint. Measurements of muscle moment arm (rm ), mass, belly length, fascicle length, pennation angle, and physiological cross-sectional area (PCSA) were taken from n = 45 muscles. Overall, most muscles studied show properties for contractile excursion and fast joint rotational velocity. However, the flexor musculature is more massive (p = 0.048) and has larger PCSA (p = 0.003) than the extensors, especially at the knee joint and digits where well-developed and strong flexors are capable of applying large joint torque. Moreover, selected hip flexors/extensors and knee flexors have modified long rm that can amplify applied joint torque in muscles with otherwise long, parallel fascicles, and one muscle (m. iliopsoas) was capable of moderately high power in B. variegatus. The architectural properties observed in the hip flexors and extensors match well with roles in suspensory braking and vertical propulsion, respectively, whereas strong knee flexors and digital flexors appear to be the main muscles providing suspensory support in the pelvic limb. With aid in support by the forelimbs and the use of adaptive slow locomotion and slow muscle fiber recruitment patterns, structure-function in the tensile limb systems of sloths appears to collectively represent an additional mechanism for energy conservation.

Three-dimensional models of the equine larynx can be used to perform traditional measures of arytenoid abduction and permit the positioning of modeled implants to demonstrate the anatomic feasibility of placing a rigid implant across the cricoarytenoid joint.

To develop 3D models of larynges to compare arytenoid abduction measurements between specimens and models, and to investigate the anatomic feasibility of placing an implant across the cricoarytenoid joint (CAJ) with or without arthrotomy. Cadaveric equine larynges (n = 9). Equine larynges underwent sequential CT scans in a neutral position and with 2 arytenoid treatments: bilateral arytenoid abduction (ABD) and bilateral arytenoid abduction after left cricoarytenoid joint arthrotomy (ARTH). Soft tissue, cartilage, and luminal volume 3-dimensional models were generated. Rima glottidis cross-sectional area (CSA) and left-to-right quotient (LRQ) angles were measured on laryngeal specimens and models. Arytenoid translation, articular contact area, and length of modeled implants placed across the CAJ were measured on models. Data were analyzed using paired t test or ANOVA and Tukey's post hoc test or non-parametric equivalents (P < .05). ARTH CSA was larger for laryngeal specimens than models (P = .0096). There was no difference in all other measures of CSA and LRQ angle between treatment groups or between specimens and models. There was no difference between ABD and ARTH groups for arytenoid cartilage translation, contact area, and implant length. The articular contact area was sufficient for modeled implant placement across the CAJ with a narrow range of implant lengths (17.59 mm to 23.87 mm) across larynges with or without arthrotomy. These results support further investigation of a CT-guided, minimally invasive surgical procedure. Future studies will evaluate the outcomes of the new procedure for technical precision, biomechanical stability, and post-operative success rates for horses with recurrent laryngeal neuropathy (RLN).

Long-term evaluation of the upper airway following mandibular setback surgery in the patients with mandibular prognathism.

The aim of this study was to evaluate the changes in the upper airway following mandibular setback surgery. The patients underwent mandibular setback surgery and cone-beam computed tomography scan data obtained at four time points: before surgery, immediately after surgery, short- and long-term follow-up. Upper airway geometries were segmented and extracted at each time point. Time-averaged airflow through the upper airway was evaluated at each time point. The measurements of airway volume and minimum cross-sectional areas were obtained at four time points. The airway volume and cross-sectional areas of airway significantly decreased immediately after surgery (p = 0.013 for airway volume and 0.016 for cross-sectional area). At short-term follow-up, the decreased airway volume and cross-sectional areas still showed statistically significant difference to original dimension (p = 0.017 for airway volume and 0.006 for cross-sectional area). At long-term follow-up, although there were no statistical significances (p = 0.859 for airway volume and 0.721 for cross-sectional area), the airway volume and cross-sectional areas had increased slightly compared to those at short-term follow-up. Although the airflow and dimensional parameters of the upper airway worsened following mandibular setback surgery, there was a tendency to gradually recover during long-term follow-up.

A novel ex vivo tracheobronchomalacia model for airway stent testing and in vivo model refinement

ObjectivesWe sought to develop an ex vivo trachea model capable of producing mild, moderate, and severe tracheobronchomalacia for optimizing airway stent design. We also aimed to determine the amount of cartilage resection required for achieving different tracheobronchomalacia grades that can be used in animal models. MethodsWe developed an ex vivo trachea test system that enabled video-based measurement of internal cross-sectional area as intratracheal pressure was cyclically varied for peak negative pressures of 20 to 80 cm H2O. Fresh ovine tracheas were induced with tracheobronchomalacia by single mid-anterior incision (n = 4), mid-anterior circumferential cartilage resection of 25% (n = 4), and 50% per cartilage ring (n = 4) along an approximately 3-cm length. Intact tracheas (n = 4) were used as control. All experimental tracheas were mounted and experimentally evaluated. In addition, helical stents of 2 different pitches (6 mm and 12 mm) and wire diameters (0.52 mm and 0.6 mm) were tested in tracheas with 25% (n = 3) and 50% (n = 3) circumferentially resected cartilage rings. The percentage collapse in tracheal cross-sectional area was calculated from the recorded video contours for each experiment. ResultsEx vivo tracheas compromised by single incision and 25% and 50% circumferential cartilage resection produce tracheal collapse corresponding to clinical grades of mild, moderate, and severe tracheobronchomalacia, respectively. A single anterior cartilage incision produces saber-sheath type tracheobronchomalacia, whereas 25% and 50% circumferential cartilage resection produce circumferential tracheobronchomalacia. Stent testing enabled the selection of stent design parameters such that airway collapse associated with moderate and severe tracheobronchomalacia could be reduced to conform to, but not exceed, that of intact tracheas (12-mm pitch, 0.6-mm wire diameter). ConclusionsThe ex vivo trachea model is a robust platform that enables systematic study and treatment of different grades and morphologies of airway collapse and tracheobronchomalacia. It is a novel tool for optimization of stent design before advancing to in vivo animal models.

The Impact of Rheumatoid Arthritis (RA) in Median Nerve Area in the Wrist Joint: A Case-Control Study.

Background Rheumatoid arthritis (RA) is one cause of carpal tunnel syndromes (CTS); due to increased intracarpal pressure in the rheumatoid wrist, synovial enlargement, joint erosions, and ligamentous laxity cause the compression of the median nerve (MN). Materials and methods A case-control study was conducted to assess the measurement of median nerve areas in RA using high-frequency ultrasound (US) and to correlate the measurement with the disease duration. Forty patients with rheumatoid arthritis (RA)and 40 with non-rheumatoid arthritis (RA) as a control group were referred to the radiology department of Yastabshiron Hospital, Khartoum, Sudan, from June to August 2022. After assessing the wrist joint by ultrasound scans, median nerve (MN) cross-sectional area (CSA)measurements were performed using a Fukuda Denshi ultrasound machine (Tokyo, Japan) with a linear-array high-frequency transducer (10 MHz), after receiving ethical approval from the research committee of the faculty of radiological science at University of Medical Sciences and Technology (UMST) and the study participants. Results The study demonstrated that the mean measurement of MN cross-sectional area (CSA) in RA patients was 13.60 mm2for the right and 13.25 mm2 forthe left MN. The study found that the MN CSA decreased by increasing the disease duration, with significant differences in the median nerve cross-sectional areas in RA and healthy control (p-value of <0.01). Conclusion The study concluded that rheumatoid arthritis (RA) had a greater influence on the median nerve cross-sectional areas. MN areas significantly decreased with increasing duration of diseases; the MN cross-sectional areas were more in RA than in the healthy control group.

Ultrasonographic Evaluation of Internal Jugular Vein for The Prediction of Post-Spinal Hypotension in Orthopedic Surgeries

Background: Relative hypovolemia may predispose to severe or prolonged hypotension after spinal anesthesia in patients undergoing orthopedic surgeries. Empirical administration of fluid preload is time consuming, costly and might lead to volume overload, especially in elderly patients. Therefore, predicting post spinal hypotension is of great importance to reserve fluid infusion for susceptible patients. Ultrasonographic evaluation of the internal jugular vein (IJV) diameter has been used to estimate intravascular volume in the ICU. Therefore, we investigated the efficacy of sonographic measurements of the internal jugular vein parameters for predicting post spinal hypotension in patients undergoing orthopedic surgeries. Methodology: The study was conducted on 62 patients scheduled for orthopedic surgeries. Sonographic measurements of IJV diameter and cross-sectional area were recorded at supine and Trendelenburg position before spinal anaesthesia. Blood pressure was monitored for 15 minutes for all patients and hypotension was documented. Results: Twenty-eight patients (45.2%) developed hypotension. The rate of increase in the diameter and cross-sectional area of the IJV with the change in patient’s posture was significantly higher in hypotensive patients. According to ROC curves analysis, a rate of increase of 12.36% in IJV diameter, and a rate of increase of 25.55% in IJV cross sectional area showed moderate specificity and sensitivity in the prediction of spinal hypotension. Conclusion: Preoperative sonographic measurements of the internal jugular vein diameter and crosssectional area at supine and Trendelenburg position can predict the occurrence of post-spinal hypotension.

Ultra-high-definition (22 MHz) ultrasound of the ulnar nerve: additional value and normative data.

We studied 30 healthy volunteers (60 arms), categorized into three age groups with equal numbers to verify if a 22 MHz compared with a 15 MHz ultrasound transducer has additional value for studying the intraneural architecture of the ulnar nerve throughout its course. At six sites, there were no differences in cross-sectional area measurements between the two transducers. With both, the cross-sectional area was significantly larger at the medial epicondyle compared with the other sites and smaller at the mid-forearm and Guyon's canal compared with the mid-upper arm. With higher age the cross-sectional area significantly increased. Significantly more fascicles were visible distal to the medial epicondyle compared with more proximal sites, as well as in men compared with women. Finally, higher body weight was related to a significantly smaller number of fascicles being seen. A 22 MHz transducer depicts more details of the intraneural architecture than a 15 MHz transducer. Our data can be used as normative data or reference values in analysing ulnar nerve pathology.Level of evidence: II.

Pyloric Functional Lumen Imaging Probe Measurements Are Dependent on Balloon Position.

The functional lumen imaging probe (FLIP) device has been used to assess pyloric dysfunction in patients with gastroparesis. We aim to investigate whether varying FLIP catheter positions affect pyloric FLIP measurements. Patients undergoing endoscopy for chronic unexplained nausea and vomiting (CUNV) or gastroparesis were prospectively enrolled. FLIP balloon was adjusted for 3 positions within the pylorus: (1) proximal position, 75% of FLIP balloon in the duodenum and 25% in the antrum; (2) middle position, 50% in the duodenum and 50% in the antrum; and (3) distal position, 25% in the duodenum and 75% in the antrum. Pylorus cross-sectional area (CSA), intra-bag pressure (P), and distensibility indices (DI) were measured for 30, 40, and 50-mL balloon volumes. Fluoroscopic images were obtained to confirm FLIP balloon geometry. Data was analyzed separately using FLIP Analytic and customized MATLAB software. Twenty-two patients with CUNV (n = 4) and gastroparesis (n = 18) were enrolled. Pressures were significantly higher in the proximal position compared to the middle and distal positions. CSA measurements were significantly higher at the proximal and middle positions for 30-mL and 40-mL volume compared to the distal position values. DI values were significantly lower at the proximal positions for 40-mL and 50-mL distensions when compared to the middle and distal positions. Fluoroscopic images confirmed increased balloon bending when placed mostly in the duodenum. FLIP balloon position within the pylorus directly affects balloon geometry which significantly affects P, CSA, and DI measurements. Standardized pyloric FLIP protocols and balloon design adjustments are needed for the continued application of this technology to the pylorus.

CT-derived psoas muscle area and density are associated with length of stay and discharge disposition after liver transplantation

Prolonged length of stay (LOS) and discharge disposition following liver transplantation are associated with postoperative complications and increased healthcare utilization. This study evaluated the relationship between CT-derived psoas muscle measurements and hospital LOS, intensive care unit (ICU) LOS, and discharge disposition after liver transplant. The psoas muscle was chosen given its ease of measurement with any radiological software. A secondary analysis assessed the relationship between the American Society for Parenteral and Enteral Nutrition and the Academy of Nutrition and Dietetics (ASPEN/AND) malnutrition diagnosis criteria and CT-derived psoas muscle measures. CT-derived measures of psoas muscle density (mHU) and cross-sectional area at the level of the third lumbar vertebrae were obtained from preoperative CT scans of liver transplant recipients. Cross-sectional area measures were corrected for body size to generate a psoas area index variable (cm2/m2; PAI). Each 1-unit increase in PAI was associated with a reduced hospital LOS of 4 days (R2=0.07). Each 5-unit increase in mean Hounsfield units (mHU) was associated with a reduced hospital and ICU LOS of 5 and 1.6 days, respectively (R2=0.22 and 0.14, respectively). Mean PAI and mHU were higher in patients who discharged to home. PAI was reasonably identified through ASPEN/AND malnutrition criteria, but there was no difference in mHU between those with and without malnutrition. Measures of psoas density were associated with both hospital and ICU LOS and discharge disposition. PAI was associated with hospital LOS and discharge disposition. CT-derived measures of psoas density may be a valuable complement to preoperative liver transplant nutrition assessment using traditional ASPEN/AND malnutrition criteria.

Quantification of sarcopenia in patients with rheumatoid arthritis by measuring the cross-sectional area of the thigh muscles with magnetic resonance imaging

PurposeTo determine the utility of cross-sectional area (CSA) measurements on magnetic resonance imaging (MRI), at the level of the thigh muscles, to estimate muscle mass in discriminating rheumatoid arthritis (RA) patients with sarcopenia from those without.Materials and methodsConsecutive female RA patients were enrolled for this cross-sectional study. Patients were assessed for disease activity, radiological damage, handgrip strength, physical performance and for the presence of sarcopenia, identified in accordance with the EWGSOP2 criteria. A 1.5 T MRI machine was used to scan the thigh muscles. A dimensional region growth algorithm (Horos™) was used to segment the muscles CSAs (in cm2) on MR images located 25 cm above the knee joint (MRI-CSA-25). The MRI-CSA-25 was obtained by summing the CSAs of the individual muscles. MRI-CSA-25 was correlated (Pearson's r) with the other variables, and its optimal cut-off point (Youden index) for sarcopenia diagnosis was identified in relation to the EWGSOP2 criteria.Results32 RA female patients were studied, 34.4% diagnosed as sarcopenic. The mean MRI-CSA-25 was 151.00 cm2 for patient with sarcopenia, 275.57 cm2 for patient without sarcopenia (p < 0.001). MRI-CSA-25 correlated significantly with measures of physical performance, and disease activity, but not with radiological damage or age. The MRI-CSA-25 optimal cut-off point in discriminating sarcopenic patients was identified at 182.00 cm2 (AUC-ROC = 0.894).ConclusionMRI-CSA-25 can differentiate sarcopenic versus non-sarcopenic RA patients, representing an imaging biomarker of this condition.

Utility of Ultrasound for Identifying Median Nerve Changes Indicative of Acute Carpal Tunnel Syndrome After Distal Radius Fracture

Ultrasound offers a fast and inexpensive way to evaluate the median nerve. However, there is a paucity of data assessing ultrasound in acute trauma. Our study aimed to characterize median nerve changes indicative of acute carpal tunnel syndrome (ACTS) in a cadaveric distal radius fracture (DRF) model. We used 10 upper-extremity specimens. We induced ACTS (carpal tunnel pressure >40 mm Hg) in a distraction-only model and then used a DRF model as a neutral position, under traction, or wrist extension. We measured the median nerve cross-sectional area (CSA), height, and width with ultrasound in each model. We used a novel calculation, height-width ratio (HWR), to describe nerve shape. A low HWR indicates an elliptical shape; as the HWR increases toward one, the shape becomes more circular. The CSA measurements and HWR at pressures >40 mm Hg were used to calculate a 95% confidence interval, which defined the threshold for ACTS. Wrist distraction created carpal tunnel pressures >40 mm Hg in all specimens. Distraction increased CSA compared with baseline (9.1 ± 0.9 mm2 vs 6.3 ± 1.2 mm2, P < .001). Under ACTS-level pressures, the thresholds for CSA and HWR were 8.5 mm2 and 0.41, respectively. HWR significantly increased with distraction compared with baseline (0.47 ± 0.10 vs 0.28 ± 0.09, P= .006). Most neutral DRF models (n= 8, 80%) met the CSA threshold for ACTS, whereas all specimens with a DRF extended or under traction had CSAs above the ACTS threshold. Compared to the baseline, the shape of the median nerve was more circular in all DRFs, including neutral (0.28 ± 0.09 vs 0.39 ± 0.13), under traction (0.43 ± 0.09), and extended (0.45 ± 0.09). ACTS should be suspected in patients with median nerves demonstrating increased CSA and adopting a more circular shape. Fracture positioning impacts median nerve CSA with wrist extension, causing the greatest change. Median nerve HWR may offer an easier ultrasonographic alternative to CSA. Diagnostic III.

Real-time measurement of minimum cross-sectional area and radius of curvature of miniature plate specimens using a high-speed laser profiler for calculating true stress-true strain curves

True stress-true strain curves are fundamental for designing and analyzing structures such as fusion reactors. These curves are typically obtained by conducting tensile tests on round bar specimens. However, due to material dimension limitations, plate specimens are sometimes used instead of round bar specimens. Obtaining true stress-true strain curves experimentally from plate specimens can be challenging. To address this challenge, this study aims to obtain true stress-true strain curves of miniature plate specimens using both analytical and experimental methods. The analytical method involved inverse finite element method (FEM), while the experimental method utilized real-time measurement of the minimum cross-sectional area and radius of curvature of a miniature plate specimen with a high-speed laser profiler. Comparing the true stresses obtained from the analytical and experimental methods, we found that the difference was typically within 5%. These findings suggest that inverse FEM and laser profilometry are effective methods for determining the true stress-true strain of miniature plate specimens.