A pilot study examining the use of ultrasound to measure sarcopenia, frailty and fall in older patients

[Thickness of the rectus femorius muscle and vastus intermedium muscle in older Mexican adults with frailty and sarcopenia]

BACKGROUND AND OBJECTIVE

Frailty in older adults is a geriatric syndrome that has gained importance in the last decade. However, there is still no consolidated information regarding diagnostic tools that allow timely identification, and therefore, provide an appropriate therapeutic approach. The objective is to determine the Thickness of the Rectus Femoris Muscle (GMRF) and Thickness of the Vastus Intermedius Muscle (GMVI) in older Mexican adults with frailty and sarcopenia.

MATERIAL AND METHODS

Cross-sectional, descriptive and comparative study in patients ≥65 years of age, admitted to the geriatrics service. The selection was according to the FRAIL (frail vs. non-frail) and SARC-F (high risk vs. low risk) classification; evaluating GMRF and GMVI by ultrasound. The data were analyzed through the statistical software Statistical Package for Social Sciences (SPSS) ver. 25.

RESULTS

The number of patients evaluated in the study and control group were 136 respectively. Significant differences were found regarding frailty status in age (years) (Frail: 75.06±7.92 vs. Non-frail: 71.60±5.56; P<.001), GMRF (mm) (Frail: 8.41±3.08 vs. Non-frail: 11.03±3.50; P<.001) and GMVI (mm) (Frail: 6.53±2.64 vs. Non-frail: 8.66±2.68; P<.001); Considering sarcopenia, there were differences in age (years) (High risk sarcopenia: 75.17±7.84: vs low risk sarcopenia; 71.49±5.60; P<.001), GMRF (mm) (high risk sarcopenia: 8.45±3.11 vs low risk sarcopenia: 10.98±3.50; P<.001) and GMVI (mm) (High risk Sarcopenia: 6.67±2.63 vs Low risk Sarcopenia: 8.52±2.79; P<.001).

CONCLUSIONS

The results found show that there is a significant difference in GMRF and GMVI in Mexican older adults with respect to frailty and sarcopenia. In this way, the present investigation establishes clinical bases for the use of ultrasonography assessments in the geriatric population.

A scoping review of geriatric emergency medicine research transparency in diversity, equity, and inclusion reporting

INTRODUCTION

The intersection of ageism and racism is underexplored in geriatric emergency medicine (GEM) research.

METHODS

We performed a scoping review of research published between January 2016 and December 2021. We included original emergency department-based research focused on falls, delirium/dementia, medication safety, and elder abuse. We excluded manuscripts that did not include (1) original research data pertaining to the four core topics, (2) older adults, (3) subjects from the United States, and (4) for which full text publication could not be obtained. The primary objective was to qualitatively describe reporting about older adults' social identities in GEM research. Secondary objectives were to describe (1) the extent of inclusion of minoritized older adults in GEM research, (2) GEM research about health equity, and (3) feasible approaches to improve the status quo of GEM research reporting.

RESULTS

After duplicates were removed, 3277 citations remained and 883 full-text articles were reviewed, of which 222 met inclusion criteria. Four findings emerged. First, race and ethnicity reporting was inconsistent. Second, research rarely provided a rationale for an age threshold used to define geriatric patients. Third, GEM research more commonly reported sex than gender. Fourth, research commonly excluded older adults with cognitive impairment and speakers of non-English primary languages.

CONCLUSION

Meaningful assessment of GEM research inclusivity is limited by inconsistent reporting of sociodemographic characteristics, specifically race and ethnicity. Reporting of sociodemographic characteristics should be standardized across different study designs. Strategies are needed to include in GEM research older adults with cognitive impairment and non-English primary languages.

A protocol to determine the acceptability and feasibility of a pilot intervention emergency department virtual observation unit fall prevention program

BACKGROUND

As a third of all community dwellers aged 65+ fall each year, falls are common reasons for older adults to present to an Emergency Department (ED). Although EDs should assess patients' multifactorial fall risks to prevent future fall-related injuries, this frequently does not occur. We describe our protocol to determine the feasibility, acceptability, and safety of a pilot ED Virtual Observation Unit (VOU) Falls program.

METHODS

To ensure standardized conduct and reporting, the Standard Protocol Items for Intervention Trials (SPIRIT) guidelines will be used. The VOU is a program where patients are sent home from the ED but are part of a virtual observation unit in that they can call on-call ED physicians while they are being treated for conditions such as cellulitis, congestive heart failure, or pneumonia. A paramedic conducts daily visits with the patient and facilitates a telemedicine consult with an ED physician. VOU nursing staff conduct daily assessments of patients via telemedicine. The ED VOU Falls program is one of the VOU pathways and is a multi-component fall prevention program for fall patients who present after an ED visit. The paramedic conducts a home safety evaluation, a Timed Up and Go Test (TUG). During the VOU visit, the ED physician conducts a telemedicine visit, while the paramedic is visiting the home, to review patients' fall-risk-increasing drugs and their TUG test. We will determine feasibility by calculating rates of patient enrollment refusal, and adherence to fall-risk prevention recommendations using information from 3-month follow-up telephone calls, as well as qualitative interviews with the paramedics. We will determine the acceptability of the ED VOU Falls program based on patient and provider surveys using a Likert scale. We will ask VOU nursing staff to report any safety issues encountered while the patient is in the ED VOU Falls program (e.g., tripping hazards). We will use the chi-square test or Fisher's exact test for categorical variables, Student's t-test for continuous variables, and Mann-Whitney for nonparametric data. We will review interview transcripts and generate codes. Codes will then be extracted and organized into concepts to generate an overall theme following grounded theory methods. This is a pilot study; hence, results cannot be extrapolated. However, a definite trial would be the next step in the future to determine if such a program could be implemented as part of fall prevention interventions.

DISCUSSION

This study will provide insights into the feasibility and acceptability of a novel ED VOU Falls program with the aim of ultimately decreasing falls. In the future, such a program could be implemented as part of fall prevention interventions.

Uncovering sarcopenia and frailty in older adults by using muscle ultrasound-A narrative review

Muscle ultrasound is a valuable non-invasive and cost-effective method in assessing muscle mass and structure, both of which are significant indicators for the development of sarcopenia and frailty in elderly individuals. Sarcopenia refers to the loss of muscle mass and strength that occurs with age, whereas frailty is a complex geriatric syndrome characterized by reduced physical function and an increased susceptibility to negative health outcomes. Both conditions are prevalent in older adults and are associated with higher risks of falls, disability, and mortality. By measuring muscle size and structure and several other ultrasound parameters, including muscle thickness, cross-sectional area, echogenicity (brightness in the ultrasound image), pennation angle, and fascicle length ultrasound can assist in identifying sarcopenia and frailty in older adults. In addition, ultrasound can be used to evaluate muscle function such as muscle contraction and stiffness, which may also be affected in sarcopenia and frailty. Therefore, muscle ultrasound could lead to better identification and tracking of sarcopenia and frailty. Such advancements could result in the implementation of earlier interventions to prevent or treat these conditions, resulting in an overall improvement in the health and quality of life of the elderly population. This narrative review describes the benefits and challenges when using ultra-sound for the evaluation of frailty and sarcopenia.

A new possible marker: can pennation angle defined by ultrasound predict the frailty?

BACKGROUND

Frailty indicates older people who are vulnerable to stressors. The relation between ultrasonographic parameters of muscle and frailty among older people has yet to be investigated.

AIMS

The aim of the study is to investigate the relationship between frailty and the ultrasonographic measurements of the rectus femoris muscle (RFM).

METHODS

This cross-sectional study included 301 participants who were ≥65 years. The FRAIL questionnaire assessed frailty. The thickness, cross-sectional area (CSA), fascicle length, pennation angle (PA), stiffness, and echogenicity of RFM were assessed by ultrasound. The accuracy of parameters in predicting the frailty was evaluated by ROC analysis.

RESULTS

Of all 301 participants, 24.6% were frail. Pre-frail and frail participants had significantly lower thickness (p = 0.002), CSA (p = 0.009), and fascicle length (p = 0.043) of RFM compared to robust. PA was significantly lowest in frails (p < 0.001). The multivariate logistic regression analysis showed that PA values lower than 10.65 degrees were an independent predictor of frailty (OR = 0.83, 95% Cl: 0.70-0.97, p = 0.019). Results of ROC analysis demonstrated a satisfactory result between the PA and frailty (AUC = 0.692, p < 0.001).

DISCUSSION

Thickness, CSA, and PA of RFM were found to be lower in frail subjects, which may indicate the changes in muscle structure in frailty. Among all parameters, lower PA values were independent predictors of frailty. These findings may indicate a novel ultrasound-based method in frailty, that is more objective and unrelated to the cross-sectional evaluation.

CONCLUSIONS

Ultrasonographic measurements of RFM, especially the lower PA may predict frailty in older people. As an objective and quantitative method, PA may be used to define frailty with acceptable sensitivity.

Development of Continuous Assessment of Muscle Quality and Frailty in Older Patients Using Multiparametric Combinations of Ultrasound and Blood Biomarkers: Protocol for the ECOFRAIL Study

BACKGROUND

Frailty resulting from the loss of muscle quality can potentially be delayed through early detection and physical exercise interventions. There is a demand for cost-effective tools for the objective evaluation of muscle quality, in both cross-sectional and longitudinal assessments. Literature suggests that quantitative analysis of ultrasound data captures morphometric, compositional, and microstructural muscle properties, while biological assays derived from blood samples are associated with functional information.

OBJECTIVE

This study aims to assess multiparametric combinations of ultrasound and blood-based biomarkers to offer a cross-sectional evaluation of the patient frailty phenotype and to track changes in muscle quality associated with supervised exercise programs.

METHODS

This prospective observational multicenter study will include patients aged 70 years and older who are capable of providing informed consent. We aim to recruit 100 patients from hospital environments and 100 from primary care facilities. Each patient will undergo at least two examinations (baseline and follow-up), totaling a minimum of 400 examinations. In hospital environments, 50 patients will be measured before/after a 16-week individualized and supervised exercise program, while another 50 patients will be followed up after the same period without intervention. Primary care patients will undergo a 1-year follow-up evaluation. The primary objective is to compare cross-sectional evaluations of physical performance, functional capacity, body composition, and derived scales of sarcopenia and frailty with biomarker combinations obtained from muscle ultrasound and blood-based assays. We will analyze ultrasound raw data obtained with a point-of-care device, along with a set of biomarkers previously associated with frailty, using quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay. Additionally, we will examine the sensitivity of these biomarkers to detect short-term muscle quality changes and functional improvement after a supervised exercise intervention compared with usual care.

RESULTS

At the time of manuscript submission, the enrollment of volunteers is ongoing. Recruitment started on March 1, 2022, and ends on June 30, 2024.

CONCLUSIONS

The outlined study protocol will integrate portable technologies, using quantitative muscle ultrasound and blood biomarkers, to facilitate an objective cross-sectional assessment of muscle quality in both hospital and primary care settings. The primary objective is to generate data that can be used to explore associations between biomarker combinations and the cross-sectional clinical assessment of frailty and sarcopenia. Additionally, the study aims to investigate musculoskeletal changes following multicomponent physical exercise programs.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05294757; https://clinicaltrials.gov/ct2/show/NCT05294757.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/50325.

Correlation of ultrasound measurement of limb muscle thickness and echo intensity with frailty assessment in elderly patients undergoing malignancies surgery

Introduction

It remains controversial which frailty score correlates with adverse outcomes. Instead of these subjective and time consuming scores, we studied whether ultrasound guided lower extremity thickness measurements more closely are associated with adverse outcomes.

Method

Patients undergoing gastrointestinal malignancy surgery were included as study subjects. Frailty was identified using the FRAIL scale assessment. Ultrasound measured the muscle thickness and echo intensity of the patient's upper and lower limbs. ANOVA was used to analyze the relationship between muscle data and frailty assessment. Significant indicators from the one-way analysis were included in the multivariate logistic regression equation.

Results

A total of 160 study subjects were included, 52 in the normal group, 78 in the prefrailty group, and 30 in the frailty group. The ANOVA showed that there were significant differences in age, hemoglobin, albumin, history of hypertension, history of coronary artery disease, the history of cerebrovascular disease, rate of postoperative complications, rate of transferring to intensive care unit, time out of bed, length of hospitalization, thickness and echo intensity of quadriceps femoris the vastus lateralis and the tibialis anterior, echo intensity of the medial gastrocnemius among the three groups (P < 0.05). Pearson's correlation analysis showed FRAIL score was correlated with muscle thickness and echo intensity of the lower limbs. Multifactor logistic regression analysis showed that the prefrailty group was positively correlated with age（β = 0.146, P = 0.004）, echo intensity of the medial gastrocnemius (β = 0.055, P = 0.031), and rate of postoperative complications（β = 1.439, P = 0.021）, also negatively correlated with muscle thickness of the tibialis anterior（β = -2.124, P = 0.007）. The frailty group was positively correlated with age（β = 0.22, P = 0.005）, tibialis anterior echo intensity (β = 0.082, P = 0.015), medial gastrocnemius echo intensity (β = 0.089, P = 0.026), cerebrovascular disease history (β = 2.311, P = 0.04), and postoperative complication rate (β = 2.684, P = 0.003). It was negatively correlated with albumin (β = -0.26, P = 0.017), quadriceps muscle thickness (β = -2.257, P = 0.017), and tibialis anterior muscle thickness (β = -5.408, P = 0.001).

Conclusion

Ultrasound measurement of lower (not upper) extremity muscle thickness and echo intensity was significantly associated with discriminating severity of frailty and postoperative outcomes than frailty scores in elderly patients.

Prolonged hospitalization and 1-year mortality are associated with sarcopenia and malnutrition in older patients with type 2 diabetes: A prospective cohort study

AIM

To assess the relationship of the presence of sarcopenia and malnutrition with unfavorable clinical outcomes: prolonged length of hospital stay (LOS), readmission, and one-year mortality in older patients with type 2 diabetes (T2D).

METHODS

Were included 319 patients with ≥ 60 years of age with T2D hospitalized at a university hospital in Southern Brazil. Sarcopenia was diagnosed according to handgrip strength (HGS), calf circumference (CC), and the timed up and go (TUG) walking test, and malnutrition according to the subjective global assessment (SGA) and the mini nutritional assessment long form (MNA-LF). Multivariate analyses, adjusted for confounders, were performed to assess the association of sarcopenia and malnutrition with clinical outcomes. One-year survival was compared using Kaplan-Meier analysis.

RESULTS

The association between sarcopenia and malnutrition increased by 2.42 times (95 %CI 1.35-4.36) the probability of LOS ≥ 14 days and by 2.01 times (95 %CI 1.09-3.72) the risk of one-year mortality. Older patients with malnutrition and sarcopenia have a higher risk of one-year mortality (log-rank p < 0.05) compared with well-nourished patients without sarcopenia.

CONCLUSION

In older patients with type 2 diabetes, those with sarcopenia, and malnutrition have higher odds of prolonged hospitalization and risk of mortality within one year after hospital discharge.

Preoperative frailty assessment with ultrasound in elderly patients scheduled for total knee arthroplasty

BACKGROUND

Frailty, a decline in physical and cognitive reserve capacity, renders patients susceptible to various stressors and has been linked to adverse outcomes and increased healthcare utilization. This study aimed to determine whether ultrasound measurements of the rectus abdominis (RA) and biceps brachii (BB) could predict frailty in patients scheduled for total knee arthroplasty.

METHODS

Frailty was assessed using the Clinical Frailty Scale in adults aged ≥60 years. Ultrasound measurements of the rectus abdominis, BB, and quadriceps femoris muscles, along with thigh circumference measurements, were obtained before surgery. The predictive ability of the unadjusted and BMI- and body surface area (BSA)-adjusted measurements were evaluated using receiver operating characteristic curve analysis and area under the curve (AUC) values. Postoperative outcomes, such as admission to the intensive care unit or skilled nursing facility, delirium, falls, re-hospitalization, and 30-day mortality were recorded.

RESULTS

We analyzed data from 148 patients. BB thickness provided a fair prediction of frailty. Average measurements of both BB adjusted for BMI (0.708, 95% CI 0.602-0.814; P<0.001), and BSA (0.708, 95% CI 0.598-0.817; P<0.001) had the highest AUC values. RA muscle measurements could not discriminate frailty. The BMI-adjusted measurements for: right quadriceps femoris thickness (AUC 0.614, 95% CI 0.503-0.725; P=0.044), left thigh circumference (AUC 0.648, 95% CI 0.528-0.769; P=0.016), and average thigh circumference (AUC 0.630, 95% CI 0.511-0.750; P=0.033) had statistically significant but poor AUC values.

CONCLUSIONS

Preoperative ultrasound measurements of the bilateral BB can fairly predict frailty in patients scheduled for total knee arthroplasty.

Older Adult Falls in Emergency Medicine, 2023 Update

Of 4 older adults, 1 will fall each year in the United States. Based on 2020 data from the Centers of Disease Control, about 36 million older adults fall each year, resulting in 32,000 deaths. Emergency departments see about 3 million older adults for fall-related injuries with falls having the ability to cause serious injury such as catastrophic head injuries and hip fractures. One-third of older fall patients discharged from the ED experience one of these outcomes at 3 months.

The role of ultrasonographically measured rectus femoris muscle on falls in community-dwelling older adults: a single-center study

BACKGROUND

There are many risk factors for falls and sarcopenia has emerged as an important risk factor. Measuring muscle mass is a useful method to determine sarcopenia. Our aim was to determine the difference in muscle mass between older adults with (fallers) and without history of falls (non-fallers) using ultrasonography (US).

METHODS

Two hundred ten geriatric patients were enrolled. Fall was defined as an event declared by the person who fell. Sarcopenia was defined by EWGSOP2 criteria. Muscle mass was assessed by muscle ultrasonography of five different muscles.

RESULTS

The mean age of the whole study group was 74.1 ± 6.3 years and 58.1% (n = 122) of the total study population was female. Among the participants, 69 patients (31.3%) had a fall history. The sarcopenia ratio was 23.2% in the fallers, and it was 13.7% in the non-fallers, the difference was statistically insignificant (p > 0.05), the measurement of rectus femoris muscle (RF) thickness and cross-sectional area (RFCSA) were significantly smaller among the fallers than non-fallers (p < 0.05). The ROC analysis revealed that RF and RFCSA could determine the history of falls [for RF area under curve (AUC): 0.606, 95% confidence interval (CI) 0.526-0.686, p = 0.010 and for RFCSA AUC: 0.621, 95% CI 0.538-0.704, p = 0.004]. RFCSA was statistically relevant with a history of falls, regardless of age, sex, multimorbidity, incontinence, nutritional status, and frailty status.

CONCLUSION

Decreased RF and RFCSA determined by muscle US is a potentially modifiable risk factor for falls in older adults. Muscle US may be used for determining the risk of falls in older adults.

Role of Muscle Ultrasound for the Study of Frailty in Elderly Patients with Diabetes: A Pilot Study

BACKGROUND

Sarcopenia and diabetes contribute to the development of frailty. Therefore, accessible methods, such as muscle ultrasounds (MUSs), to screen for sarcopenia should be implemented in clinical practice.

METHODS

We conducted a cross-sectional pilot study including 47 patients with diabetes (mean age: 77.72 ± 5.08 years, mean weight: 75.8 kg ± 15.89 kg, and body mass index: 31.19 ± 6.65 kg/m²) categorized as frail by the FRAIL Scale or Clinical Frailty Scale and confirmed by Fried's Frailty Phenotype or Rockwood's 36-item Frailty Index. We used the SARC-F questionnaire to identify sarcopenia. The Short Physical Performance Battery (SPPB) and the Timed Up and Go (TUG) tests were used to assess physical performance and the risk of falls, respectively. In addition, other variables were measured: fat-free mass (FFM) and Sarcopenia Risk Index (SRI) with the bioimpedance analysis (BIA); thigh muscle thickness (TMT) of the quadriceps with MUS; and hand-grip strength with dynamometry.

RESULTS

We observed correlations between the SARC-F and FFM (R = -0.4; p < 0.002) and hand-grip strength (R = -0.5; p < 0.0002), as well as between the TMT and FFM of the right leg (R = 0.4; p < 0.02) and the SRI (R = 0.6; p < 0.0001). We could predict sarcopenia using a logistic regression model with a ROC curve (AUC = 0.78) including FFM, handgrip strength, and TMT. The optimal cut-off point for maximum efficiency was 1.58 cm for TMT (sensitivity = 71.4% and specificity = 51.5%). However, we did not observe differences in the TMT among groups of greater/less frailty based on the SARC-F, SPPB, and TUG (p > 0.05).

CONCLUSIONS

MUSs, which correlated with the BIA (R = 0.4; p < 0.02), complemented the diagnosis, identifying regional sarcopenia of the quadriceps in frail patients with diabetes and improving the ROC curve to AUC = 0.78. In addition, a TMT cut-off point for the diagnosis of sarcopenia of 1.58 cm was obtained. Larger studies to validate the MUS technique as a screening strategy are warranted.

Muscle Architecture and Subcutaneous Fat Measurements of Rectus Femoris and Vastus Lateralis at Optimal Length Aided by a Novel Ultrasound Transducer Attachment

Purpose: This cross-sectional study determines the sensitivity of muscle architecture and fat measurements of the rectus femoris (RF) and vastus lateralis (VL) muscles from ultrasound images acquired with varying transducer tilt, using a novel transducer attachment, in healthy adults. Secondary objectives were to estimate intrarater and interrater reliability of image measurement and acquisition, respectively. Methods: Thirty healthy adults participated (15 women and 15 men; 25 [SD 2.5] y). Ultrasound image acquisition was conducted by two raters at different transducer tilts relative to the skin: estimated perpendicular, and five measured angles (80°, 85°, 90°, 95°, 100°) using the transducer attachment. Muscle thickness (MT), subcutaneous fat thickness (FT), pennation angle (PA), and fascicle length (FL) were measured. Sensitivity and reliability were assessed using intra-class correlation coefficients (ICCs) and standard error of measurements (SEMs). Results: MT and FT for RF and VL were not sensitive to transducer tilt. However, PA and FL were sensitive to transducer tilt. MT and FT for both muscles showed high ICCs and low SEMs for intrarater and interrater reliability. For PA of both muscles, standardizing transducer tilt improved interrater ICCs and lowered SEMs. Conclusion: MT and FT measurements of RF and VL acquired at 60° knee flexion are robust to varying transducer tilt angles. PA measurements benefit from standardizing transducer tilt.

Association of Sonographic Sarcopenia and Falls in Older Adults Presenting to the Emergency Department

BACKGROUND AND OBJECTIVE

To determine the association between point-of-care-ultrasonography (POCUS)-measured sarcopenia and grip strength, as well as the history of prior-year falls among older adults admitted to the emergency department observation unit (EDOU).

MATERIALS AND METHODS

This cross-sectional observational study was conducted over 8 months at a large urban teaching hospital. A consecutive sample of patients who were 65 years or older and admitted to the EDOU were enrolled in the study. Using standardized techniques, trained research assistants and co-investigators measured patients' biceps brachii and thigh quadriceps muscles via a linear transducer. Grip strength was measured using a Jamar Hydraulic Hand Dynamometer. Participants were surveyed regarding their history of falls in the prior year. Logistic regression analyses assessed the relationship of sarcopenia and grip strength to a history of falls (the primary outcome).

RESULTS

Among 199 participants (55% female), 46% reported falling in the prior year. The median biceps thickness was 2.22 cm with an Interquartile range [IQR] of 1.87-2.74, and the median thigh muscle thickness was 2.91 cm with an IQR of 2.40-3.49. A univariate logistic regression analysis demonstrated a correlation between higher thigh muscle thickness, normal grip strength, and history of prior-year falling, with an odds ratio [OR] of 0.67 (95% conference interval [95%CI] 0.47-0.95) and an OR of 0.51 (95%CI 0.29-0.91), respectively. In multivariate logistic regression, only higher thigh muscle thickness was correlated with a history of prior-year falls, with an OR of 0.59 (95% CI 0.38-0.91).

CONCLUSIONS

POCUS-measured thigh muscle thickness has the potential to identify patients who have fallen and thus are at high risk for future falls.

Open-Ended Transmission Coaxial Probes for Sarcopenia Assessment

We developed a handheld, side-by-side transmission-based probe for interrogating tissue to diagnose sarcopenia—a condition largely characterized by muscle loss and replacement by fat. While commercial microwave reflection-based probes exist, they can only be used in a lab for a variety of applications. The penetration depth of these probes is only in the order of 0.3 mm, which does not even traverse the skin layer, and minor motion of the coaxial feedlines can completely dismantle the calibration. Our device builds primarily on the transmission-based concept that allows for substantially greater signal penetration depth operating over a very broad bandwidth. Additional features were integrated to further improve the penetration, optimize the geometry for a more focused planar excitation, and juxtapose the coaxial apertures for more controlled interrogation. The larger coaxial apertures further increased the penetration depth while retaining the broadband performance. Three-dimensional printing technology made it possible for the apertures to be compressed into ellipses for interrogation in a near-planar geometry. Finally, fixed side-by-side positioning provided repeatable and reliable performance. The probes were also not susceptible to multipath signal corruption due to the close proximity of the transmitting and receiving apertures. The new concept worked from 100 MHz to over 8 GHz and could sense property changes as deep as 2–3 cm. While the signal changes due to deeper feature aberrations were more subtle than for signals emanating from the skin and subcutaneous fat layers, the large property contrast between muscle and fat is a sarcopenic indication that helps to distinguish even the deepest objects. This device has the potential to provide needed specificity information about the relevant underlying tissue.

Point-of-care lung ultrasound for the assessment of pneumonia: a narrative review in the COVID-19 era

In the coronavirus disease-2019 (COVID-19) era, point-of-care lung ultrasound (LUS) has attracted increased attention. Prospective studies on LUS for the assessment of pneumonia in adult patients were extensively carried out for more than 10 years before this era. None of these prospective studies attempted to differentiate bacterial and viral pneumonia in adult patients using LUS. The majority of studies considered the LUS examination to be positive if sonographic consolidations or multiple B-lines were observed. Significant differences existed in the accuracy of these studies. Some studies revealed that LUS showed superior sensitivity to chest X-ray. These results indicate that point-of-care LUS has the potential to be an initial imaging modality for the diagnosis of pneumonia. The LUS diagnosis of ventilator-associated pneumonia in intensive care units is more challenging in comparison with the diagnosis of community-acquired pneumonia in emergency departments due to the limited access to the mechanically ventilated patients and the high prevalence of atelectasis. However, several studies have demonstrated that the combination of LUS findings with other clinical markers improved the diagnostic accuracy. In the COVID-19 era, many case reports and small observational studies on COVID-19 pneumonia have been published in a short period. Multiple B-lines were the most common and consistent finding in COVID-19 pneumonia. Serial LUS showed the deterioration of the disease. The knowledge and ideas on the application of LUS in the management of pneumonia that are expected to accumulate in the COVID-19 era may provide us with clues regarding more appropriate management.