We wish to acknowledge a contract (WS1763368) from Pfizer Pharmaceuticals for support in this work. We would also like to thank the Saudi Arabian Ministry of Higher Education (MOHE) for their support.

1. The Exercise
<ol>
 <li>The muscle of interest for this experiment was the elbow flexors (Biceps Brachii).</li>
 <li>Muscle strength was measured for each participant to be able to give each individual an appropriate resistance. This was determined by testing each participant for their resistance maximum (RM).</li>
 <li>For testing the RM, we used a strain gauge device interfaced with a computer through a BioPac (DA-100C) bioelectric amplifier module (BioPac Systems, Goleta, CA) to measure muscle strength. The module was connected to an MP-100 analog to digital converter sampling at a frequency of 1,000 hertz per second, and at a resolution of 24 bits (Fig. 10).</li>
 <li>The strain gauge device was fixed to a bench at a 45&deg; angle. The subjects were instructed to sit behind the device and rest their elbows on the padded area, so that the exertion force is through their wrists. This was the best way to insure that the subject will not recruit any muscle other than the biceps (Fig. 11).</li>
 <li>Strength was determined on 3 occasions with each contraction being 3 seconds in duration with approximately 45 seconds separating the contractions. The average of the 3 measurements was the RM.</li>
 <li>After determining the RM for the biceps muscle of each participant, the intended session of exercise was carried out with 35% of their RM.</li>
 <li>All the subjects underwent the same exercise using appropriate weighted dumbbells to induce the muscle soreness (DOMS). This was carried out by doing 4 sets of 25 repetitions of biceps concentration curls while seated on a chair, and with the elbows supported on their thighs (Fig. 12).</li>
 <li>Each subject was given a 90 second resting period between each set. Subjects either did the full set of 25 repetitions, or were instructed to stop if they failed to steadily control the weight during the exercise.</li>
</ol>
2. Infra-Red Camera Preparation &amp; Setup
<ol>
 <li>The room where the infra-red imaging takes place was set at a constant temperature to minimize any external bias from differences in room temperature, which could lead to false thermal readings. For the purpose of this experiment we had a temperature controlled room which was maintained at approximately 23&deg;C (+/- 0.5&deg;C).</li>
 <li>The camera was set at a distance of 1 meter away, and at a perpendicular angle to the skin being measured (Fig. 9a)*.</li>
 <li>After the required distance was set up, the subjects were advised to stand still until the image has been taken. This shouldn't take more than a couple of seconds, but it is very critical to minimize movement to insure the accuracy of the taken image.</li>
 <li>It is preferable that the room has darker colored paint, rather than lighter colors, to minimize any infra-red interference.</li>
 <li>Lighting is also critical when dealing with infra-red images, because light source that emit infra-red waves like fluorescent or tungsten lighting could give false high readings. The best lighting option would be a room equipped with uniform LED lights, as LED lights hardly produce any infra-red interference (Fig. 9b)*.</li>
</ol>
* A series of tests were done at our labs using the FLIR 660 IR Camera (Fig. 8), where we compared images of the skin at different angles (0 (perpendicular), 15, 30, 45, and 60 degrees), and at different distances (1, 2, and 5 meters) from the skin, to accurately detect the temperature of the skin. All images were compared to calibrated thermocouples, and the best correlation between the images and the thermocouple readings was at a perpendicular angle and at a distance of 1 meter away from the skin (r = 0.93). The different angles and distances caused a pixilation loss, and decreased the overall correlation between the images and the thermocouple readings.
3. Image Acquirement
<ol>
 <li>For the purpose of this experiment, the image of the exercised muscle was taken before the exercise, and at 24, and 48 hours post exercise.</li>
 <li>Body heat from sources other than the target could disrupt the thermal image and give false readings. For this reason, no one should be standing beside or behind the intended target.</li>
 <li>In this investigation, pictures of both the exercised and non-exercised arm were taken for comparison purposes. We exercised one of the arms, as was mentioned previously, and the other arm was used as a control (Fig. 4 and 5).</li>
 <li>Image numbers from the IR camera were recorded immediately on a separate spreadsheet, as it could be difficult to identify which image belongs to whom.</li>
</ol>
4. Image Processing &amp; Analyses
<ol>
 <li>The acquired IR images were processed using the "ThermoVision ExaminIR" software Version: 1.10.2.</li>
 <li>After selecting the required image for analysis, four regions of interest were identified on the acquired image of the arm using statistical boxes on the software interface (Fig.6).</li>
 <li>When the required regions across the arm have been located, the software shows the Means and Standard Deviations of the temperatures for each of the selected regions. We can then either cross compare each region individually or obtain an average temperature of the whole arm (Fig. 7).</li>
</ol>
5. Visual Analog Scale &amp; Blood Analysis
<ol>
 <li>A visual analog scale (VAS) was used to assess subjective soreness of the arm. The scale had a 10 cm (100mm) long line marked "no pain" at one end, and "extremely sore" at the opposite end. Each participant was directed to make a mark along the 10 cm line to indicate their response to soreness.</li>
 <li>The VAS's were administered to the subjects before the exercise, 24 hours after the exercise, and at 48 hours.</li>
 <li>Peripheral blood was collected from the subjects to measure myoglobin concentration levels in the blood.</li>
 <li>The blood was drawn from the subjects antecubital vein before the exercise, 30 minutes after the exercise was over, and at 48 hours.</li>
 <li>The blood was centrifuged at 4000 rpm for 10 min to separate the serum from the cells. The samples were then stored at -80&deg;C until the analyses of myoglobin was done.</li>
 <li>Myoglobin was measured using a TOSOH "AIA-360" Automated enzyme Immunoassay Analyzer (TOSOH Corp., Tokyo, Japan). The myoglobin Assay kits (Myo 025297, ST AIA-PACK Myoglobin) were used according to the manufactures instructions.</li>
</ol>
6. Representative Results
The results of IR thermal images taken during this investigation are clearly represented in figure 1. Images taken at the 3 time periods (pre-exercise, 24 hours post-exercise, and 48 hours post-exercise) for the exercised arms of the 41 subjects, showed a noticeable increase in temperature on day 2 (24 hours post-exercise) when compared to pre-exercise temperatures, and temperatures taken at 48 hours. As shown in figure 1, the average skin temperature was 32.80 +/- 1.03 &deg;C for day 1 (pre-exercise), and 33.96 +/- 1.46 &deg;C for day 2 (24 hours post-exercise), and 32.82 +/- 1.29 for day 3 (48 hours post-exercise). This difference in skin temperature from day 1 to day 2 was significant (ANOVA p &lt; 0.01).
However, for the un-exercised arm, changes amongst the 3 time periods were not evident. Figure 1 shows that the average skin temperature was 33.08 +/- 0.83 &deg;C for day 1 (pre-exercise), and 32.79 +/- 1.42 &deg;C for day 2 (24 hours post-exercise), and 33.17 +/- 0.95 for day 3 (48 hours post-exercise). This difference in skin temperature over the 3 days was not significant (ANOVA p = 0.38).
The results of the pain readings from the VAS are shown in figure 2. As seen in figure 2, the reported pain had a dramatic increase on days 2 and 3. Pain levels of the exercised muscle increased from 3.6 +/- 6.1 on day 1, to 36.3 +/- 22.8 on day 2, and 37.5 +/- 25.3 on day 3. This increase from day 1 was significant (ANOVA p &lt; 0.01).
The results of the myoglobin concentration levels are shown in figure 3. As seen in this figure, there was hardly any change between the 2 myoglobin concentrations on day 1 (pre, &amp; 30 minutes post exercise). But on day 3, the increase in myoglobin was very large. This increase on day 3 was approximately 147 nanograms per milliliter (ng/mL) of blood when compared to the first 2 concentrations on day 1. Myoglobin concentrations were 30.12 +/- 7.66 ng/mL at baseline, 31.66 +/- 11.89 ng/mL 30 minutes post exercise, and 178.96 +/- 249.51 ng/mL on day 3. This increase on day 3 was highly significant (ANOVA p &lt; 0.01).
A correlation analysis was done between the skin temperatures obtained from the IR images, and the VAS soreness levels. It was found that there was a considerable correlation between the VAS readings on day 2, and the skin temperature measurement on day 2. This correlation was significant (r = 0.312, p &lt; 0.05). However, there was no evident correlation between the VAS readings and the skin temperatures on day 3. This correlation was insignificant (r = 0.047, p = 0.77).
<img src="/files/ftp_upload/3551/3551fig1.jpg" alt="Figure 1"/> 
Figure 1. A representative graph of the differences in skin temperature in the exercised arms (Diamonds), and un-exercised arms (Squares) of the 41 subjects over the 3 day time period.
<img src="/files/ftp_upload/3551/3551fig2.jpg" alt="Figure 2"/> 
Figure 2. A representative graph of the differences in perceived muscle soreness measured with the VAS over the 3 day time period for all the 41 subjects.
<img src="/files/ftp_upload/3551/3551fig3.jpg" alt="Figure 3"/> 
Figure 3. A representative graph of the differences in myoglobin concentrations for all the 41 subjects over the 3 time periods.

<img src="/files/ftp_upload/3551/3551fig4.jpg" alt="Figure 4"/> 
Figure 4. A) a typical IR image of a subject's exercised arm before the exercise. B) an IR image of the same subjects arm 24 hours after the exercise.
<img src="/files/ftp_upload/3551/3551fig5.jpg" alt="Figure 5"/> 
Figure 5. A) a typical IR image of a subject's un-exercised arm before the exercise. B) an IR image of the same subjects arm 24 hours after the exercise.
<img src="/files/ftp_upload/3551/3551fig6.jpg" alt="Figure 6"/> 
Figure 6. An illustration of the 4 regions of interest for analyzing the thermal image of the arm.
<img src="/files/ftp_upload/3551/3551fig7.jpg" alt="Figure 7"/> 
Figure 7. Software interface for the "ThermoVision ExaminIR" showing the 4 boxes of interest on an IR image of an exercised arm. Also shown are the statistical interpretations for each box.
<img src="/files/ftp_upload/3551/3551fig8.jpg" alt="Figure 8"/> 
Figure 8. The IR thermal camera used for this investigation (FLIR 660).
<img src="/files/ftp_upload/3551/3551fig9.jpg" alt="Figure 9"/> 
Figure 9. A) The Setup of the IR Camera 1 meter away from the subjects arm. B) The LED lights used in the lab where the images were taken.
<img src="/files/ftp_upload/3551/3551fig10.jpg" alt="Figure 10"/> 
Figure 10. A) The BioPac Modules used for measuring the muscle strength. B) The strain gauge device fixed to a 45&deg; angled bench and hooked to the BioPac system.
<img src="/files/ftp_upload/3551/3551fig11.jpg" alt="Figure 11"/> 
Figure 11. A typical subject exerting force on the strain gauge device.
<img src="/files/ftp_upload/3551/3551fig12.jpg" alt="Figure 12"/> 
Figure 12. A subject undergoing the exercise protocol for inducing the muscle soreness.

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No conflicts of interests declared.

The primary purpose of this investigation was to assess the usefulness of thermal IR imaging in detecting and measuring muscle soreness after strenuous exercise, and our results suggest that IR imaging could be a valid technique for detecting DOMS, especially within the first 24 hours of exercising. This is not surprising, as Pennes18 provided a very detailed model of heat flow from muscle to skin in limbs. This model predicts that heat in deeper tissues such as muscles can be dissipated into blood and into th...

<table><tbody><tr><td>Infra-Red Thermal Camera</td><td>FLIR Systems Inc.</td><td>FLIR SC660</td><td></td></tr><tr><td>Thermal Infra-Red Analysis Software</td><td>Thermo Fisher Scientific, Inc.</td><td>Software Version 1.10.2</td><td></td></tr><tr><td>Bi&amp;#8211;lectric Amplifier Module</td><td>Biopac Systems, Inc.</td><td>DA100C</td><td>The DA100C provides variable gain settings, and adjustable voltage references.</td></tr><tr><td>Analog to Digital Converter Module</td><td>Biopac Systems, Inc.</td><td>MP100</td><td></td></tr><tr><td>Automated enzyme Immunoassay Analyzer</td><td>Tosoh Corp.</td><td>AIA -360</td><td>This device was used to analyze the blood samples, and obtain the myoglobin readings.</td></tr></tbody></table>

the use of thermal infra-red imaging to detect delayed onset muscle soreness

Delayed onset muscle soreness (DOMS), also known as exercise induced muscle damage (EIMD), is commonly experienced in individuals who have been physically inactive for prolonged periods of time, and begin with an unexpected bout of exercise1-4, but can also occur in athletes who exercise beyond their normal limits of training5. The symptoms associated with this painful phenomenon can range from slight muscle tenderness, to severe debilitating pain1,3,5. The intensity of these symptoms and the related discomfort increases within the first 24 hours following the termination of the exercise, and peaks between 24 to 72 hours post exercise1,3. For this reason, DOMS is one of the most common recurrent forms of sports injury that can affect an individual&#x2019;s performance, and become intimidating for many1,4.
For the last 3 decades, the DOMS phenomenon has gained a considerable amount of interest amongst researchers and specialists in exercise physiology, sports, and rehabilitation fields6. There has been a variety of published studies investigating this painful occurrence in regards to its underlying mechanisms, treatment interventions, and preventive strategies1-5,7-12. However, it is evident from the literature that DOMS is not an easy pathology to quantify, as there is a wide amount of variability between the measurement tools and methods used to quantify this condition6. It is obvious that no agreement has been made on one best evaluation measure for DOMS, which makes it difficult to verify whether a specific intervention really helps in decreasing the symptoms associated with this type of soreness or not. Thus, DOMS can be seen as somewhat ambiguous, because many studies depend on measuring soreness using a visual analog scale (VAS)10,13-15, which is a subjective rather than an objective measure. Even though needle biopsies of the muscle, and blood levels of myofibre proteins might be considered a gold standard to some6, large variations in some of these blood proteins have been documented 6,16, in addition to the high risks sometimes associated with invasive techniques. 
Therefore, in the current investigation, we tested a thermal infra-red (IR) imaging technique of the skin above the exercised muscle to detect the associated muscle soreness. Infra-red thermography has been used, and found to be successful in detecting different types of diseases and infections since the 1950&#x2019;s17. But surprisingly, near to nothing has been done on DOMS and changes in skin temperature. The main purpose of this investigation was to examine changes in DOMS using this safe and non-invasive technique.

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The Use of Thermal Infra-Red Imaging to Detect Delayed Onset Muscle Soreness

The purpose of this investigation was to assess whether using an infra-red thermal camera is a valid tool for detecting and quantifying the muscle soreness after exercising.

Delayed onset muscle soreness (DOMS), also known as exercise induced muscle damage (EIMD), is commonly experienced in individuals who have been physically ...

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19.2K Views.  Loma Linda University. The purpose of this investigation was to assess whether using an infra-red thermal camera is a valid tool for detecting and quantifying the muscle soreness after exercising.

Video: The Use of Thermal Infra-Red Imaging to Detect Delayed Onset Muscle Soreness

Quantitative Visualization and Detection of Skin Cancer Using Dynamic Thermal Imaging

In 2010 approximately 68,720 melanomas will be diagnosed in the US alone, with around 8,650 resulting in death 1. To date, the only effective treatment for melanoma remains surgical excision, therefore, the key to extended survival is early detection 2,3. Considering the large numbers of patients diagnosed every year and the limitations in accessing specialized care quickly, the development of objective in vivo diagnostic instruments to aid the diagnosis is essential. New techniques to detect skin cancer, especially non-invasive diagnostic tools, are being explored in numerous laboratories. Along with the surgical methods, techniques such as digital photography, dermoscopy, multispectral imaging systems (MelaFind), laser-based systems (confocal scanning laser microscopy, laser doppler perfusion imaging, optical coherence tomography), ultrasound, magnetic resonance imaging, are being tested. Each technique offers unique advantages and disadvantages, many of which pose a compromise between effectiveness and accuracy versus ease of use and cost considerations. Details about these techniques and comparisons are available in the literature 4.
Infrared (IR) imaging was shown to be a useful method to diagnose the signs of certain diseases by measuring the local skin temperature. There is a large body of evidence showing that disease or deviation from normal functioning are accompanied by changes of the temperature of the body, which again affect the temperature of the skin 5,6. Accurate data about the temperature of the human body and skin can provide a wealth of information on the processes responsible for heat generation and thermoregulation, in particular the deviation from normal conditions, often caused by disease. However, IR imaging has not been widely recognized in medicine due to the premature use of the technology 7,8 several decades ago, when temperature measurement accuracy and the spatial resolution were inadequate and sophisticated image processing tools were unavailable. This situation changed dramatically in the late 1990s-2000s. Advances in IR instrumentation, implementation of digital image processing algorithms and dynamic IR imaging, which enables scientists to analyze not only the spatial, but also the temporal thermal behavior of the skin 9, allowed breakthroughs in the field.
In our research, we explore the feasibility of IR imaging, combined with theoretical and experimental studies, as a cost effective, non-invasive, in vivo optical measurement technique for tumor detection, with emphasis on the screening and early detection of melanoma 10-13. In this study, we show data obtained in a patient study in which patients that possess a pigmented lesion with a clinical indication for biopsy are selected for imaging. We compared the difference in thermal responses between healthy and malignant tissue and compared our data with biopsy results. We concluded that the increased metabolic activity of the melanoma lesion can be detected by dynamic infrared imaging.

We demonstrated that malignant pigmented lesions with increased metabolic activity generate quantifiable amounts of heat and the measurement of the transient thermal response of the skin to a cooling excitation allows quantitative identification of melanoma and other skin cancers (vs. non-proliferative nevi) at an early stage of the disease.

In 2010 approximately 68,720 melanomas will be diagnosed in the US alone, with around 8,650 resulting in death 1. To date, the only effective treatment ...

A Protocol of Manual Tests to Measure Sensation and Pain in Humans

Numerous qualitative and quantitative techniques can be used to test sensory nerves and pain in both research and clinical settings. The current study demonstrates a quantitative sensory testing protocol using techniques to measure tactile sensation and pain threshold for pressure and heat using portable and easily accessed equipment. These techniques and equipment are ideal for new laboratories and clinics where cost is a concern or a limiting factor. We demonstrate measurement techniques for the following: cutaneous mechanical sensitivity on the arms and legs (von-Frey filaments), radiant and contact heat sensitivity (with both threshold and qualitative assessments using the Visual Analog Scale (VAS)), and mechanical pressure sensitivity (algometer, with both threshold and the VAS). The techniques and equipment described and demonstrated here can be easily purchased, stored, and transported by most clinics and research laboratories around the world. A limitation of this approach is a lack of automation or computer control. Thus, these processes can be more labor intensive in terms of personnel training and data recording than the more sophisticated equipment. We provide a set of reliability data for the demonstrated techniques. From our description, a new laboratory should be able to set up and run these tests and to develop their own internal reliability data.

The goal of this procedure is to demonstrate a battery of quantitative techniques for sensory and pain measurement in humans. The equipment and techniques described are commonly found in pain clinics or are easy to obtain.

Numerous qualitative and quantitative techniques can be used to test sensory nerves and pain in both research and clinical settings. The current study ...

Behavior

A Novel Application of Musculoskeletal Ultrasound Imaging

Ultrasound is an attractive modality for imaging muscle and tendon motion during dynamic tasks and can provide a complementary methodological approach for biomechanical studies in a clinical or laboratory setting. Towards this goal, methods for quantification of muscle kinematics from ultrasound imagery are being developed based on image processing. The temporal resolution of these methods is typically not sufficient for highly dynamic tasks, such as drop-landing. We propose a new approach that utilizes a Doppler method for quantifying muscle kinematics. We have developed a novel vector tissue Doppler imaging (vTDI) technique that can be used to measure musculoskeletal contraction velocity, strain and strain rate with sub-millisecond temporal resolution during dynamic activities using ultrasound. The goal of this preliminary study was to investigate the repeatability and potential applicability of the vTDI technique in measuring musculoskeletal velocities during a drop-landing task, in healthy subjects. The vTDI measurements can be performed concurrently with other biomechanical techniques, such as 3D motion capture for joint kinematics and kinetics, electromyography for timing of muscle activation and force plates for ground reaction force. Integration of these complementary techniques could lead to a better understanding of dynamic muscle function and dysfunction underlying the pathogenesis and pathophysiology of musculoskeletal disorders.

We describe a new ultrasound-based vector tissue Doppler imaging technique to measure muscle contraction velocity, strain and strain rate with sub-millisecond temporal resolution during dynamic activities. This approach provides complementary measurements of dynamic muscle function and could lead to a better understanding of mechanisms underlying musculoskeletal disorders.

Ultrasound is an attractive modality for imaging muscle and tendon  motion during dynamic tasks and can provide a complementary methodological  approach ...

Measuring Skeletal Muscle Thermogenesis in Mice and Rats

Skeletal muscle thermogenesis provides a potential avenue for better understanding metabolic homeostasis and the mechanisms underlying energy expenditure. Surprisingly little evidence is available to link the neural, myocellular, and molecular mechanisms of thermogenesis directly to measurable changes in muscle temperature. This paper describes a method in which temperature transponders are utilized to retrieve direct measurements of mouse and rat skeletal muscle temperature.
Remote transponders are surgically implanted within the muscle of mice and rats, and the animals are given time to recover. Mice and rats must then be repeatedly habituated to the testing environment and procedure. Changes in muscle temperature are measured in response to pharmacological or contextual stimuli in the home cage. Muscle temperature can also be measured during prescribed physical activity (i.e., treadmill walking at a constant speed) to factor out changes in activity as contributors to the changes in muscle temperature induced by these stimuli.
This method has been successfully used to elucidate mechanisms underlying muscle thermogenic control at the level of the brain, sympathetic nervous system, and skeletal muscle. Provided are demonstrations of this success using predator odor (PO; ferret odor) as a contextual stimulus and injections of oxytocin (Oxt) as a pharmacological stimulus, where predator odor induces muscle thermogenesis, and Oxt suppresses muscle temperature. Thus, these datasets display the efficacy of this method in detecting rapid changes in muscle temperature.

Mice and rats are surgically implanted with remote temperature transponders and then habituated to the testing environment and procedure. Changes in muscle temperature are measured in response to pharmacological or contextual stimuli in the home cage or during prescribed physical activity (i.e., treadmill walking at a constant speed).

Skeletal muscle thermogenesis provides a potential avenue for better understanding metabolic homeostasis and the mechanisms underlying energy expenditure. ...

Induction and Assessment of Exertional Skeletal Muscle Damage in Humans

Contraction-induced muscle damage via voluntary eccentric (lengthening) contractions offers an excellent model for studying muscle adaptation and recovery in humans. Herein we discuss the design of an eccentric exercise protocol to induce damage in the quadriceps muscles, marked by changes in strength, soreness, and plasma creatine kinase levels. This method is simple, ethical, and widely applicable since it is performed in human participants and eliminates the interspecies translation of the results. Subjects perform 300 maximal eccentric contractions of the knee extensor muscles at a speed of 120&#176;/sec on an isokinetic dynamometer. The extent of the damage is measurable using relatively non-invasive isokinetic and isometric measures of strength loss, soreness, and plasma creatine kinase levels over several days following the exercise. Therefore, its application can be directed to specific populations in an attempt to identify mechanisms for muscle adaptation and regeneration.

This article describes a safe and reliable method to induce and quantify exertional skeletal muscle damage in human subjects.

Contraction-induced muscle damage via voluntary eccentric (lengthening) contractions offers an excellent model for studying muscle adaptation and recovery ...

Skeletal Muscle Neurovascular Coupling, Oxidative Capacity, and Microvascular Function with 'One Stop Shop' Near-infrared Spectroscopy

Exercise represents a major hemodynamic stress that demands a highly coordinated neurovascular response in order to match oxygen delivery to metabolic demand. Reactive hyperemia (in response to a brief period of tissue ischemia) is an independent predictor of cardiovascular events and provides important insight into vascular health and vasodilatory capacity. Skeletal muscle oxidative capacity is equally important in health and disease, as it determines the energy supply for myocellular processes. Here, we describe a simple, non-invasive approach using near-infrared spectroscopy to assess each of these major clinical endpoints (reactive hyperemia, neurovascular coupling, and muscle oxidative capacity) during a single clinic or laboratory visit. Unlike Doppler ultrasound, magnetic resonance images/spectroscopy, or invasive catheter-based flow measurements or muscle biopsies, our approach is less operator-dependent, low-cost, and completely non-invasive. Representative data from our lab taken together with summary data from previously published literature illustrate the utility of each of these end-points. Once this technique is mastered, application to clinical populations will provide important mechanistic insight into exercise intolerance and cardiovascular dysfunction.

Here, we describe a simple, non-invasive approach using near-infrared spectroscopy to assess reactive hyperemia, neurovascular coupling and skeletal muscle oxidative capacity in a single clinic or laboratory visit.

Exercise represents a major hemodynamic stress that demands a highly coordinated neurovascular response in order to match oxygen delivery to metabolic ...

Real-Time Magnetic Resonance Guided Focused Ultrasound for Painful Bone Metastases

Bones are one of the most common sites of cancer metastasis, which usually causes pain and impairs quality of life. Radiation therapy combined with opioids is the standard treatment for painful bone metastases. This treatment achieves effective pain control in 60&#8722;74% of patients, but limited treatment choices with limited benefits are available for recurrent or residual painful bone metastases after radiotherapy. More than 40% of patients still experience moderate to severe bone pain after reirradiation. Magnetic resonance-guided focused ultrasound (MRgFUS) combines high-intensity focused ultrasound, which achieves thermal ablation of bone metastases and subsequent pain reduction, with real-time magnetic resonance (MR) thermometry to monitor the temperature of anatomic MR images, with an accuracy of 1 &#176;C, spatial resolution of 1 mm, and temporal resolution within 3 s. As well as being increasingly used clinically for controlling metastatic bone pain, the use of MRgFUS for other diseases has also been tested. However, the use of MR software as a thermometer is the only technique available to verify the accuracy of the software and assure energy delivery. Here, we describe an efficient method of quality assurance we developed for thermal detection and energy delivery before each MRgFUS treatment and also propose a modified workflow to expedite the treatment course as well as to reduce patients&#39; pain during the procedure.

Magnetic resonance could offer real-time monitoring of the position and temperature of focused ultrasound in thermal ablation for painful bone metastases, regardless of cancer type or previous local treatments. Our innovative method of quality assurance could facilitate the application of this effective and safe treatment.

Bones are one of the most common sites of cancer metastasis, which usually causes pain and impairs quality of life. Radiation therapy combined with ...

Infrared Thermography for the Detection of Changes in Brown Adipose Tissue Activity

Measuring brown adipose tissue (BAT) activity by positron emission tomography computed tomography (PET-CT) via the accumulation of 18F-fluorodeoxyglucose (FDG) after a meal or in obese or diabetic patients fails as the method of choice. The main reason is that 18F-FDG competes with the postprandial high glucose plasma concentration for the same glucose transporter on the membrane of BAT cells. In addition, BAT uses fatty acids as a source of energy as well, which is not visible with PET-CT and could be changed along with glucose concentration in obese and diabetic patients. Therefore, to estimate the physiological importance of BAT in animals and humans, a new infrared thermography method used in recent publications is applied.
After overnight fasting, BAT activity was measured by infrared thermography before and after a meal in human volunteers and&#160;female wild-type mice. The camera software calculates the object&#39;s temperature using distance from the object, skin emissivity, reflected room temperature, air temperature, and relative humidity. In mice, the shaved area above the BAT was a region of interest for which average and maximal temperatures were measured. The phase of the estrous cycle in female mice was determined after an experiment by vaginal smears stained with cresyl violet (0.1%) stain solution. In healthy volunteers, two skin areas of the neck were selected: the supraclavicular area (above the collarbone, where BAT cells are present) and the interclavicular area (between the collarbones, where there is no BAT tissue detected). BAT activity is determined by the subtraction of those two values. Also, the average and maximal temperatures of skin areas could be determined in animals and human participants.
Changes in BAT activity after a meal measured by infrared thermography, a non-invasive and more sensitive method, were shown to be sex, age, and phase of the estrous cycle dependent in laboratory animals. As part of diet-induced thermogenesis, BAT activation in humans was also proven to be sex, age, and body mass index dependent. Further determining the pathophysiological changes in BAT activity after a meal will be of great importance for participants with high glucose plasma concentrations (obesity and diabetes mellitus type 2), as well as in different laboratory animals (knock-out mice). This method is also a variable tool for determining possible activating drugs that could rejuvenate BAT activity.

Here, we present a protocol for measuring brown adipose tissue activity after a meal in humans and laboratory animals.

Measuring brown adipose tissue (BAT) activity by positron emission tomography computed tomography (PET-CT) via the accumulation of 18F-fluorodeoxyglucose ...

Ultrasound Evaluation of Achilles Tendon Morphology

Measurement of Healthy and Injured Triceps Surae Morphology

Achilles tendon injuries occur throughout the lifespan and can negatively affect quality of life and overall health. Achilles tendinopathy is generally classified as an overuse injury associated with fusiform tendon thickening, neovascularization, and interstitial tendon degeneration. Current literature suggests these structural changes are associated with&#160;symptoms and lower physical activity levels, as well as&#160;symptoms and lower extremity function in the long term. Surgically and non-surgically managed Achilles tendon ruptures result in increased tendon cross-sectional area (CSA) and a lengthened Achilles tendon. Both structural outcomes have clinical implications, as larger CSA positively predicts function, whereas increased tendon lengthening predicts reduced function after Achilles tendon rupture. Given the relationship between structural changes associated with Achilles tendon injuries for both injury severity and injury recovery, it is critical to be able to quantify Achilles tendon structure reliably and accurately. Silbernagel&#39;s group has established a valid and reliable method for efficiently evaluating triceps surae muscle and tendon structure. In this protocol, B-mode musculoskeletal ultrasound imaging is used to measure triceps surae structure, including Achilles tendon thickness and CSA, soleus thickness, and the presence of additional findings (calcifications and bursitis). B-mode extended field-of-view is used to measure Achilles tendon length and gastrocnemius anatomical CSA. Finally, power Doppler is used to identify intratendinous neovascularization. Quantification of triceps surae structure allows for comparison between limbs as well as longitudinal changes in response to exercise and treatment for healthy individuals and those with Achilles tendon injuries. This protocol has been used in many research studies to date and proves valuable in understanding the relationship between tendon structure and injury development, severity, and recovery. As ultrasound devices are becoming more affordable and portable, this protocol proves promising as a clinical tool, given its quick and efficient methods.

Author Spotlight: Exploring the Complexities of Achilles Tendon Injuries &#8212; Research and Future Directions

Ultrasound imaging is becoming more accessible in clinical and research settings, and a consistent protocol will be beneficial for comparison between studies and for clinical interpretations. This protocol for ultrasound evaluation is a valid and reliable method to evaluate Achilles tendon morphology in healthy, tendinopathic, and ruptured tendons.

Achilles tendon injuries occur throughout the lifespan and can negatively affect quality of life and overall health. Achilles tendinopathy is generally ...

Using Near-Infrared Spectroscopy Wearable Devices to Identify Central Versus Peripheral Limitations During Exercise

The gold standard to assess the aerobic capacity in physically active subjects and athletes is the maximal oxygen consumption test (VO2&#8211;max), which involves analysis of exhaled&#8211;gases and cardiorespiratory variables obtained via the breath-by-breath method in an ergospirometer during an incremental exercise. However, this method cannot elucidate metabolic changes at the muscular level. Near-infrared spectroscopy (NIRS) has emerged as a valuable technology to evaluate local oxygen levels (Tissular Saturation Index, TSI) by quantifying the concentrations of oxygenated (O2-Hb) and deoxygenated (H-Hb) hemoglobin in the microvasculature of tissues. NIRS applications extend to respiratory and locomotor muscles, assessing metabolic changes associated with the cost of breathing (COB) and peripheral workload, respectively. Additionally, cerebral regions, such as the prefrontal cortex, have been explored with NIRS technology to assess physiological changes related to cognitive demand associated with planning or ideation of motor tasks linked to sports performance. Thus, by analyzing exercise-induced changes (D) in O2-Hb, H-Hb, and TSI, it is possible to identify central and peripheral exercise limitations, particularly when endurance training is the main component of physical fitness (e.g., running, cycling, triathlon, etc.). Addressing these factors is paramount for coaches and exercise physiologists to optimize athletic performance, incorporating training strategies focused on the primary exercise-limiting factors. This study outlines a protocol for utilizing wearables devices equipped with NIRS technology to analyze exercise changes in TSI, O2-Hb, and H-Hb, alongside cardiorespiratory variables typically registered in athletes during VO2&#8211;max tests. This approach offers a comprehensive method for identifying the primary systems involved in stopping exercise progression and sports performance improvement.

This protocol integrates near-infrared spectroscopy (NIRS) technology to assess localized hematological and oxygenation changes at the prefrontal cortex, respiratory (m.Intercostales), and locomotor (m.Vastus Lateralis) muscles during cardiopulmonary exercise testing, enabling the identification of central and peripheral limiting factors affecting exercise performance.

The gold standard to assess the aerobic capacity in physically active subjects and athletes is the maximal oxygen consumption test (VO2&#8211;max), which ...