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Ultrasonography advantageously measures skeletal muscle size and quality, but some muscles may be too large to capture with standardized brightness mode (B-mode) imaging. Panoramic ultrasonography can capture more complete images and may more accurately measure muscle size. We investigated measurements made using panoramic compared to B-mode ultrasonography images of the rectus femoris with muscular performance. Concurrently, protein intake plays an important role in preventing sarcopenia; therefore, we also sought to investigate the association between animal-based protein intake (ABPI) and muscular performance. Ninety-one middle-aged adults were recruited. Muscle cross-sectional area (CSA) and thickness were obtained using B-mode and panoramic ultrasound and analyzed with Image J software. Muscular performance was assessed using isokinetic dynamometry, a 30-s chair test, and handgrip strength. Three-day food diaries estimated dietary intakes. Linear regression models determined relationships between measures from ultrasonography and muscular performance. Mixed linear models were used to evaluate the association between ABPI and muscular performance. Muscle CSA from panoramic ultrasonography and ABPI were positively associated with lower-body strength (β ± S.E.; CSA, 42.622 ± 20.024, p = 0.005; ABPI, 65.874 ± 19.855, p = 0.001), lower-body endurance (β ± S.E.; CSA, 595 ± 200.221, p = 0.001; ABPI, 549.944 ± 232.478, p = 0.020), and handgrip strength (β ± S.E.; CSA, 6.966 ± 3.328, p = 0.004; ABPI, 0.349 ± 0.171, p = 0.045). Panoramic ultrasound shows promise as a method for assessing sarcopenia. ABPI is related to better muscular performance.

Few studies have measured the effects of multi-ingredient pre-workout supplements on blood flow or heart rate variability or have compared a multi-ingredient pre-workout supplement to a matched single ingredient. This study examined the effects of a multi-ingredient pre-workout supplement, an equivalent amount of caffeine, and placebo on markers of resistance training performance, blood flow, blood pressure, and heart rate variability. The study utilized a randomized, placebo-controlled, repeated-measures, crossover design. Twelve resistance-trained males (22.75 ± 4.51 yrs; 183.4 ± 7.37 cm; 91.05 ± 17.77 kg) completed the study. Resistance exercise performance was defined as total work performed during elbow flexion and extension on an isokinetic dynamometer. Blood flow was calculated using time-averaged mean velocity and blood vessel diameter of the right brachial artery, which were measured via Doppler ultrasound. Heart rate was recorded using an electrocardiogram. Neither a multi-ingredient pre-workout supplement nor caffeine alone improved upper-body resistance exercise performance or markers of blood flow relative to placebo. No differences in heart rate variability were observed across treatments. A multi-ingredient pre-workout supplement was not effective at improving performance or blood flow and did not alter autonomic nervous system function.

Background: The use of magnetic resonance imaging (MRI) derived functional cross-sectional area (FCSA) and intramuscular adipose tissue (IMAT) to define skeletal muscle quality is of fundamental importance in order to understand aging and inactivity-related loss of muscle mass., Objectives: This study examined factors associated with lower-extremity skeletal muscle quality in healthy, younger, and middle-aged adults., Design: Cross-sectional study., Setting and Participants: Ninety-eight participants (53% female) were classified as younger (20-35 years, n=50) or middle-aged (50-65 years, n=48) as well as sedentary (≤1 day per week) or active (≥3 days per week) on self-reported concurrent exercise (aerobic and resistance)., Measurements: All participants wore an accelerometer for seven days, recorded a three-day food diary, and participated in magnetic resonance imaging (MRI) of the lower limbs. Muscle cross-sectional area (CSA) was determined by tracing the knee extensors (KE) and plantar flexors, while muscle quality was established through the determination of FCSA and IMAT via color thresholding., Results: One-way analysis of variance and stepwise regression models were performed to predict FCSA and IMAT. KE-IMAT (cm2) was significantly higher among sedentary (3.74 ± 1.93) vs. active (1.85 ± 0.56) and middle-aged (3.14 ± 2.05) vs. younger (2.74 ± 1.25) (p < 0.05). Protein intake (g•kg•day-1) was significantly higher in active (1.63 ± 0.55) vs. sedentary (1.19 ± 0.40) (p < 0.05). Sex, age, concurrent exercise training status, and protein intake were significant predictors of KE FCSA (R2 = 0.71, p < 0.01), while concurrent exercise training status and light physical activity predicted 33% of the variance in KE IMAT (p < 0.01)., Conclusion: Concurrent exercise training, dietary protein intake, and light physical activity are significant determinants of skeletal muscle health and require further investigation to mitigate aging and inactivity-related loss of muscle quality., Competing Interests: There are no conflicts of interest.

Introduction: The purpose of the current study was to examine if isometric peak force and rate of force development (RFD) were related to the ability to successfully perform a simulated casualty evacuation task in both unweighted and weighted conditions., Methods: Eighteen male participants from Army Reserve Officers' Training Corps (ROTC) completed a maximum isometric deadlift on a force plate (IRB#HE16227). Isometric peak force and RFD were calculated from ground reaction force. Two simulated casualty evacuation performance trials were then completed. The unweighted trial consisted of lifting and carrying a 75 kg dummy as quickly as possible for 50 m. The weighted trial was similar except 9 kg vests were added to both the simulation dummy and the participant to represent 18 kg of duty gear. Independent sample t-tests and Pearson correlations were performed to compare the characteristics of those who passed and failed the weighted trial., Results: All of the participants (n = 18) completed the unweighted casualty evacuation trial, while 72% (n = 13) were able to complete the weighted casualty evacuation trial. The participants that successfully completed the weighted evacuation trial had significantly (p < 0.05) greater isometric peak force (1420 ± 165 vs. 1076 ± 256 N) and lean mass (74.18 ± 3.89 vs. 65.34 ± 3.89 kg) when compared to participants (n = 5) that could not complete the weighted evacuating task trial. Additionally, greater Army Physical Fitness Test scores (288 ± 13 vs. 269 ± 16 arbitrary units) and significantly faster (30.34 ± 4.41 vs. 44.92 ± 10.62 seconds) unweighted evacuation trial times were observed in participants that could complete the weighted evacuation task. Peak force was also significantly correlated with lean mass (r = 0.51, p < 0.05). There was no relationship between RFD and performance of the unweighted or weight trial., Conclusion: Isometric deadlift peak force represents an important determinant for the success of a simulated casualty evacuation task and may be a useful marker to include in periodic fitness evaluations of military personnel., (© Association of Military Surgeons of the United States 2019. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The purpose of this study was to examine the acute endothelial, cardiovascular, and performance responses to L-arginine intake by assessing flow-mediated dilation (FMD) and various indicators (e.g., heart rate, heart rate variability (HRV), blood pressure, torque) both before and after resistance exercise. Thirty (15 male, 15 female) physically active participants (mean ± SD: age 20.4 ± 1.8 years, height 176.9 ± 10.2 cm, body mass 76.0 ± 12.2 kg) volunteered for a randomized, cross-over, double-blind, placebo-controlled clinical trial. Participants completed five sets of elbow extension-flexion exercise after consumption of either 3 g L-arginine or 3 g of placebo. There was a significant decline in post-exercise elbow extension ( p = 0.014) and flexion peak torque ( p < 0.001). FMD response after exercise was ~5.8% less than before resistance exercise (L-arginine and placebo data pooled, p < 0.001). Baseline brachial artery diameter significantly increased post-FMD ( p < 0.001), post-resistance exercise ( p < 0.001), and post-resistance exercise FMD ( p < 0.001). There were significant time effects for HRV when expressed as the square root of the mean of the sum of squares of differences between adjacent RR intervals (RMSSD) or the proportion of differences between adjacent normal (NN) RR intervals that exceed 50 ms (pNN50) (all p -values < 0.05), but there were no treatment or interaction effects (all p -values > 0.05). We conclude the increased vasodilation due to acute resistance exercise was not enhanced by acute supplementation with L-arginine nor was exercise performance augmented. Further, the relative contribution of sympathetic nervous system input increased with resistance exercise but was not influenced by the addition of L-arginine.

Background: The ergogenic effect is a highly practical and relevant topic in sports research, particularly in strength sports where numerous strategies have gained widespread recognition. Despite reports indicating challenges in the simultaneous use of various ergogenic strategies, our understanding of how they are practically employed is limited. This study aimed to determine and evaluate preferences in the use of nutritional and non-nutritional means of eliciting the ergogenic effect of individuals regularly participating in strength training. Materials and Methods: A total of 108 participants completed an original, online questionary shared on social media sites and created using Google Forms. Significance of differences was determined with Chi-square test. Results: A significant majority of responders declared use of nutritional (90%) and non-nutritional (62%) ergogenic aids, however only insignificant majority declared simultaneously using more than one ergogenic aid (56%). The most popular nutritional means of eliciting the ergogenic effect were caffeine, coffee and creatine; non-nutritional were listening to music and dynamic stretching; the most popular combinations of two means of eliciting the ergogenic effect were caffeine with music and caffeine with creatine; and the most popular combinations of three means of eliciting the ergogenic effect were caffeine with creatine and music. Only age of participants influenced preferences in use of ergogenic means, where group 18 - 25 declared using non-nutritional means of eliciting ergogenic effect significantly more frequent. Conclusion: Results of the study indicate that the majority of polish as well as foreign strength trainees employ ergogenic aids, typically favoring well-established options supported by scientific literature. [ABSTRACT FROM AUTHOR]

Serial myocardial imaging with technetium-99m methoxyisobutyl isonitrile (99mTc-MIBI) has been proposed for evaluating myocardial salvage after reperfusion. To define 99mTc-MIBI uptake before and after reperfusion, 17 open-chest dogs underwent 3 hours of left anterior descending artery occlusion and 3 hours of reperfusion. 99mTc-MIBI was injected during occlusion (group 1) or after 90 minutes of reperfusion (group 2). Myocardial 99mTc-MIBI activity was correlated with microsphere flow during occlusion and reperfusion. Anatomic risk area and infarct area were defined by postmortem vital staining and correlated with the perfusion defects defined by analysis of 99mTc-MIBI macroautoradiographs and gamma camera images of myocardial slices. The left ventricle was divided into 96 segments for gamma well counting. Flow and 99mTc-MIBI activity were normalized to nonischemic values. Myocardial segments were grouped, based on occlusion flow, into zones: severely ischemic (less than or equal to 30% nonischemic), moderately ischemic (greater than 30%, less than or equal to 60% nonischemic), mildly ischemic (greater than 60%, less than or equal to 90% nonischemic), and nonischemic (greater than 90%, less than or equal to 120% nonischemic). Among dogs injected with 99mTc-MIBI during coronary occlusion (group 1), myocardial 99mTc-MIBI activity correlated linearly with occlusion flow for both endocardial (r = 0.91) and transmural (r = 0.91) segments. The risk area defined by 99mTc-MIBI autoradiography (group 1) correlated with the postmortem risk area (rho = 0.94) but was 29% smaller than the anatomic risk area (p = 0.03), reflecting the contribution of collateral flow. Among dogs injected with 99mTc-MIBI after reperfusion (group 2), myocardial 99mTc-MIBI did not correlate with reperfusion flow in either endocardial or transmural segments. Among group 2 dogs, myocardial 99mTc-MIBI activity was significantly less than reperfusion flow at the time of injection in the severely ischemic (25 +/- 5% versus 74 +/- 24% nonischemic, p = 0.002), moderately ischemic (54 +/- 12% versus 96 +/- 15% nonischemic, p = 0.001), and mildly ischemic (84 +/- 6% versus 93 +/- 3% nonischemic, p = 0.002) zones. The defect area defined by 99mTc-MIBI autoradiography (group 2) correlated very closely with the postmortem infarct area (rho = 0.98). Thus, the myocardial uptake of 99mTc-MIBI during coronary occlusion correlates with occlusion flow and reflects the "area at risk." When 99mTc-MIBI was given after 90 minutes of reperfusion following 3 hours of coronary occlusion, the myocardial activity was significantly reduced compared with reperfusion flow in both necrotic and perinecrotic regions, reflecting myocardial viability more than the degree of reperfusion.

Caffeine and beta-alanine are widely used in multi-ingredient pre-workout supplements believed to enhance resistance training, but their specific role in driving this effect remains unclear. The current study employed a randomized, triple-blinded, placebo-controlled and crossover experimental design to explore the acute effects of caffeine (200 mg), beta-alanine (3 g), or their combination (200 mg caffeine and 3 g beta-alanine; C+B-A) administered 30 min prior to resistance training (RT) on mechanical, physiological, and perceptual variables. Twenty-one young resistance-trained males (age = 23.5 ± 4.5 years, body mass = 82.1 ± 10.2 kg) visited the laboratory on six occasions: one familiarization session, one preliminary testing session for load determination, and four experimental sessions which differed only in supplementation condition and involved four supersets of bench press and bench pull exercises. The supplement condition did not significantly affect any mechanical variables (p ≥ 0.335), except for the velocity of the last repetition of the set, where beta-alanine produced lower values (0.383 m/s) compared to placebo (0.407 m/s; p < 0.05), with no differences observed for C+B-A (0.397 m/s) and caffeine (0.392 m/s). Heart rate was consistent across the different supplement conditions with the exception of the higher values observed immediately before the start of the RT session for placebo compared to caffeine (p = 0.010) and C+B-A (p = 0.019). Post-RT blood lactate concentration (p = 0.384), general and local ratings of perceived exertion (p = 0.177 and 0.160, respectively), and readiness (p = 0.281-0.925), did not differ significantly between supplement conditions. Selected supplements have minimal effects on performance and physiological responses in agonist-antagonist upper-body superset RT not leading to failure., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

L-Arg is a nonessential amino acid but has many physiological roles. Accordingly, L-Arg has been used in various fields, but there is only limited information available about its safety upon overdose. Generally, the no-observed adverse effect level (NOAEL) is used when setting the upper amount for chemical substances. Recently, systematic reviews have been used to assess the safety as well as the effectiveness and usefulness of them. Therefore, we conducted an assessment of the safety of the oral intake of L-Arg in healthy subjects using gastrointestinal symptoms as an index. We limited the study design to only double-blind randomized controlled trials and searched PubMed, Cochrane Library, EBSCOhost, and Ichushi-Web from inception until May 2021. Assessment of the quality of studies was conducted using the Cochrane Collaboration tool and Jadad score, and the random effects model was used for data analysis. Ultimately, 34 studies were selected for inclusion in this work. The dosage of L-Arg used in the studies ranged from 2000 to 30,000 mg/day (or/one-time dose), and the treatment duration was 1–84 days. The increased risk of gastrointestinal symptoms associated with L-Arg intake from 23 studies (647 participants in total) in which such symptoms were reported was 0.01 (95% confidence interval: – 0.02–0.04), which was not significant difference. NOAEL was estimated as 7531 mg/ one-time dose using a weighted change-point regression model (UMIN000046133). Registration and protocol: Umin.ac.jp as UMIN000046133. [ABSTRACT FROM AUTHOR]

Skeletal muscle size is an important factor in assessing adaptation to exercise training and detraining, athletic performance, age-associated atrophy and mobility decline, clinical conditions associated with cachexia, and overall skeletal muscle health. Magnetic resonance (MR) imaging and computed tomography (CT) are widely accepted as the gold standard methods for skeletal muscle size quantification. However, it is not always feasible to use these methods (e.g., field studies, bedside studies, and large cohort studies). Ultrasound has been available for skeletal muscle examination for more than 50 years and the development, utility, and validity of ultrasound imaging are underappreciated. It is now possible to use ultrasound in situations where MR and CT imaging are not suitable. This review provides a comprehensive summary of ultrasound imaging and human skeletal muscle size assessment. Since the first study in 1968, more than 600 articles have used ultrasound to examine the cross-sectional area and/or volume of 107 different skeletal muscles in more than 27,500 subjects of various ages, health status, and fitness conditions. Data from these studies, supported by decades of technological developments, collectively show that ultrasonography is a valid tool for skeletal muscle size quantification. Considering the wide-ranging connections between human health and function and skeletal muscle mass, the utility of ultrasound imaging will allow it to be employed in research investigations and clinical practice in ways not previously appreciated or considered. [ABSTRACT FROM AUTHOR]

Concurrent training incorporates dual exercise modalities, typically resistance and aerobic-based exercise, either in a single session or as part of a periodized training program, that can promote muscle strength, mass, power/force and aerobic capacity adaptations for the purposes of sports performance or general health/wellbeing. Despite multiple health and exercise performance-related benefits, diminished muscle hypertrophy, strength and power have been reported with concurrent training compared to resistance training in isolation. Dietary protein is well-established to facilitate skeletal muscle growth, repair and regeneration during recovery from exercise. The degree to which increased protein intake can amplify adaptation responses with resistance exercise, and to a lesser extent aerobic exercise, has been highly studied. In contrast, much less focus has been directed toward the capacity for protein to enhance anabolic and metabolic responses with divergent contractile stimuli inherent to concurrent training and potentially negate interference in muscle strength, power and hypertrophy. This review consolidates available literature investigating increased protein intake on rates of muscle protein synthesis, hypertrophy, strength and force/power adaptations following acute and chronic concurrent training. Acute concurrent exercise studies provide evidence for the significant stimulation of myofibrillar protein synthesis with protein compared to placebo ingestion. High protein intake can also augment increases in lean mass with chronic concurrent training, although these increases do not appear to translate into further improvements in strength adaptations. Similarly, the available evidence indicates protein intake twice the recommended intake and beyond does not rescue decrements in selective aspects of muscle force and power production with concurrent training. [ABSTRACT FROM AUTHOR]

In the last few years, a plethora of studies have explored the effects of caffeine on resistance exercise, demonstrating that this field of research is growing fast. This review evaluates and summarizes the most recent findings. Given that toxic doses of caffeine are needed to increase skeletal muscle contractility, the binding of caffeine to adenosine receptors is likely the primary mechanism for caffeine's ergogenic effects on resistance exercise. There is convincing evidence that caffeine ingestion is ergogenic for (i) one-repetition maximum, isometric, and isokinetic strength; and (ii) muscular endurance, velocity, and power in different resistance exercises, loads, and set protocols. Furthermore, there is some evidence that caffeine supplementation also may enhance adaptations to resistance training, such as gains in strength and power. Caffeine ingestion is ergogenic for resistance exercise performance in females, and the magnitude of these effects seems to be similar to that observed in men. Habitual caffeine intake and polymorphisms within CYP1A2 and ADORA2A do not seem to modulate caffeine's ergogenic effects on resistance exercise. Consuming lower doses of caffeine (e.g., 2–3 mg/kg) appears to be comparably ergogenic to consuming high doses of caffeine (e.g., 6 mg/kg). Minimal effective doses of caffeine seem to be around 1.5 mg/kg. Alternate caffeine sources such as caffeinated chewing gum, gel, and coffee are also ergogenic for resistance exercise performance. With caffeine capsules, the optimal timing of ingestion seems to be 30–60 min before exercise. Caffeinated chewing gums and gels may enhance resistance exercise performance even when consumed 10 min before exercise. It appears that caffeine improves performance in resistance exercise primarily due to its physiological effects. Nevertheless, a small portion of the ergogenic effect of caffeine seems to be placebo-driven. [ABSTRACT FROM AUTHOR]

Background: Soccer is an extremely competitive sport, where the most match important moments can be defined in detail. Use of ergogenic supplements can be crucial to improve the performance of a high-performance athlete. Therefore, knowing which ergogenic supplements are important for soccer players can be an interesting strategy to maintain high level in this sport until final and decisive moments of the match. In addition, other supplements, such as dietary supplements, have been studied and increasingly referenced in the scientific literature. But, what if ergogenic supplements were combined with dietary supplements? This review brings some recommendations to improve performance of soccer athletes on the field through dietary and/or ergogenic supplements that can be used simultaneously. Summary: Soccer is a competitive sport, where the match important moments can be defined in detail. Thus, use of ergogenic supplements covered in this review can improve performance of elite soccer players maintaining high level in the match until final moments, such as creatine 3–5 g day−1, caffeine 3–6 mg kg−1 BW around 60 min before the match, sodium bicarbonate 0.1–0.4 g kg−1 BW starting from 30 to 180 min before the match, β-alanine 3.2 and 6.4 g day−1 provided in the sustained-release tablets divided into 4 times a day, and nitrate-rich beetroot juice 60 g in 200 mL of water (6 mmol of NO3− L) around 120 min before match or training, including a combination possible with taurine 50 mg kg−1 BW day−1, citrulline 1.2–3.4 g day−1, and arginine 1.2–6 g day−1. Key Messages: Soccer athletes can combine ergogenic and dietary supplements to improve their performance on the field. The ergogenic and dietary supplements used in a scientifically recommended dose did not demonstrate relevant side effects. The use of various evidence-based supplements can add up to further improvement in the performance of the elite soccer players. [ABSTRACT FROM AUTHOR]

Women have recently been integrated into ground close combat positions; however, there are limited data in women in these roles. We aimed to test the hypothesis that there would be no sex-specific neuromuscular responses, but hormonal signaling would be differentially impacted when exposed to simulated military operational stress (SMOS). Neuromuscular performance was assessed daily using a tactical mobility test (TMT) in 54 male and 15 female military members. Blood was drawn before/after TMT. Mood states were assessed each morning. Unloaded 300-m shuttle time increased 6% in both sexes and remained 7% higher after 1 day of recovery compared with baseline (p<0.05 for both), whereas performance was maintained in other TMT events (p>0.05). Growth hormone increased in men, but not women, before to after TMT (p, 0.001 vs. p 5 0.086). Women experienced a greater decline in insulin-like growth factor-I across days compared with men (npp 5 0.778 vs. 0.209, respectively, p, 0.001). Brain-derived neurotrophic factor increased significantly in men only from before to after TMT on day 1 (men: +107% vs. women: +10%) but no difference on days 3 or 4. Cortisol increased 69% from before to after TMT when averaged by sex and day. Negative mood states (depression, tension, and anger) and altered hormonal concentrations were associated with poorer TMT performance. Acute SMOS differentially impacted circulating hormonal milieu in men and women, but no differences in physical performance responses. Unloaded 300-m shuttle was negatively impacted while other fitness domains were maintained. Relationships between performance and mood/endocrine signaling highlight the potential for self-report measures and biomarkers to serve as indicators of performance change. [ABSTRACT FROM AUTHOR]

Context Military personnel are subjected to physiologically stressful environments during combat and its associated training. Evidence suggests that fish oil–derived n-3 polyunsaturated fatty acids (FO n-3 PUFAs) may affect military personnel's performance by promoting or preserving lean body mass, strength, and power, while enhancing recovery from training-associated muscle damage. Objective Following PRISMA guidelines, this systematic review assessed the evidence for FO n-3 PUFA supplementation across various military-relevant outcomes related to physical performance in healthy adult populations. Data Sources The PubMed, Embase, and the CINAHL databases were searched along with references lists of selected articles and reviews. Data Extraction Eighteen trials were assessed for bias, and descriptive data were extracted. Data Analysis Of the 18 studies included, 12 trials favored FO n-3 PUFA supplementation in ≥ 1 of the performance outcomes. Conclusion Overall, FO n-3 PUFA supplementation likely preserves strength and very likely enhances recovery from physiological stress in young, healthy adults. However, FO n-3 PUFAs' role in promoting or preserving lean body mass or promoting strength is unclear and warrants additional investigation. Systematic Review Registration PROSPERO registration no. CRD42020152786. [ABSTRACT FROM AUTHOR]

Aims Determination of the myocardium at risk (MaR) and final infarct size by cardiac magnetic resonance imaging (CMR) enables calculation of salvaged myocardium in acute infarction. T2-weighted imaging is performed prior to the administration of gadolinium, since gadolinium affects T2 tissue properties. This is, however, difficult in an ex vivo model since gadolinium must be administered for determination of infarct size by CMR. We aimed to test the ability of ex vivo T2-weighted imaging to assess MaR using myocardial perfusion single photon emission computed tomography (SPECT) as reference and to investigate whether MaR could be assessed by ex vivo T2-weighted imaging after injection of gadolinium. Materials and methods In 18 domestic pigs, the left anterior descending artery was occluded for either 30 or 40 min, followed by 4 h of reperfusion. After explantation of the hearts, myocardial perfusion SPECT and T2-weighted imaging were performed for determination of MaR, either with or without gadolinium. Infarct size was determined by T1-weighted imaging and by triphenyl tetrazolium chloride (TTC) staining. Results T2-weighted imaging agreed with myocardial perfusion SPECT, both with and without gadolinium (r2= 0.70, P < 0.01) with a bias of 2.6 ± 5.1% (P = 0.04). Infarct size was 15.4 ± 5.3 and 22.1 ± 5.6% with TTC and T1-weighted imaging, respectively (P = 0.008) in nine pigs who had both infarct measures. Conclusion T2-weighted CMR imaging can be used to determine MaR in an ex vivo experimental model, both with and without the presence of gadolinium. Thus, CMR alone can be used to assess myocardial salvage in experimental studies. [ABSTRACT FROM AUTHOR]

Molecular imaging of the cardiovascular system heavily relies on the development of new imaging probes and technologies to facilitate visualization of biological processes underlying or preceding disease. Molecular imaging is a highly active research discipline that has seen tremendous growth over the past decade. It has broadened our understanding of oncologic, neurologic, and cardiovascular diseases by providing new insights into the in vivo biology of disease progression and therapeutic interventions. As it allows for the longitudinal evaluation of biological processes, it is ideally suited for monitoring treatment response. In this review, we will concentrate on the major accomplishments and advances in the field of molecular imaging of atherosclerosis and myocardial infarction with a special focus on magnetic resonance imaging. [ABSTRACT FROM AUTHOR]

Background: Advances in the management of myocardial infarction have resulted in substantial reductions in morbidity and mortality. Methods: However, after acute treatment a number of diagnostic and prognostic questions often remain to be answered, whereby cardiac imaging plays an essential role. Results: For example, some patients will sustain early mechanical complications after infarction, while others may develop significant ventricular dysfunction. Furthermore, many individuals harbour a significant burden of residual coronary disease for which clarification of functional ischaemic status and/or viability of the suspected myocardial territory is required. Conclusion: Cardiac magnetic resonance (CMR) imaging is well positioned to fulfil these requirements given its unparalleled capability in evaluating cardiac function, stress ischaemia testing and myocardial tissue characterisation. This review will focus on the utility of CMR in resolving diagnostic uncertainty, evaluating early complications following myocardial infarction, assessing inducible ischaemia, myocardial viability, ventricular remodelling and the emerging role of CMR-derived measures as endpoints in clinical trials. Key Points: • Cardiac magnetic resonance (CMR) imaging identifies early complications after myocardial infarction. • Adenosine stress CMR can reliably assess co-existing disease in non-culprit arteries. • Assessment of infarct size and microvascular obstruction a robust prognostic indicator. • Assessment of myocardial viability is important to guide revascularisation decision-making. [ABSTRACT FROM AUTHOR]

Objective Validation of methods to assess the area at risk (AAR) in patients with ST elevation myocardial infarction is limited. A study was undertaken to test different AAR methods using established physiological concepts to provide a reference standard. Main outcome measured In 78 reperfused patients with first ST elevation myocardial infarction, AAR was measured by electrocardiographic (Aldrich), angiographic (Bypass Angioplasty Revascularization Investigation (BARI), APPROACH) and cardiovascular magnetic resonance methods (T2-weighted hyperintensity and delayed enhanced endocardial surface area (ESA)). The following established physiological concepts were used to evaluate the AAR methods: (1) AAR size is always ≥ infarct size (IS); (2) in transmural infarcts AAR size=IS; (3) correlation between AAR size and IS increases as infarct transmurality increases; and (4) myocardial salvage ((AAR-IS)/AAR3100) is inversely related to infarct transmurality. Results Overall, 65%, 87%, 76%, 87% and 97% of patients using the Aldrich, BARI, APPROACH, T2-weighted hyperintensity and ESA methods obeyed the concept that AAR size is ≥IS. In patients with transmural infarcts (n=22), Bland Altman analysis showed poor agreement e (wide 95% limits of agreement) between AAR size and IS for the BARI, Aldrich and APPROACH methods (95% CI - 22.9 to 29.6, 95% CI - 28.3 to 21.3 and 95% CI - 16.9 to 20.0, respectively) and better agreement for T2- weighted hyperintensity and ESA (95% CI - 6.9 to 16.6 and 95% CI - 4.3 to 18.0, respectively). Increasing correlation between AAR size and IS with increasing infarct transmurality was observed for the APPROACH, T2- weighted hyperintensity and ESA methods, with ESA having the highest correlation (r=0.93, p<0.001). The percentage of patients within a narrow margin (±30%) of the inverse line of identity between salvage extent and infarct transmurality was 56%, 76%, 65%, 77% and 92% for the Aldrich, BARI, APPROACH, T2-weighted hyperintensity and ESA methods, respectively, where higher percentages represent better concordance with the concept that the extent of salvage should be inversely related to infarct transmurality. Conclusions For measuring AAR, cardiovascular magnetic resonance methods are better than angiographic methods, which are better than electrocardiographic methods. Overall, ESA performed best for measuring AAR in vivo. [ABSTRACT FROM AUTHOR]

Acute coronary syndromes (ACS) continue to be the most common morbid condition of industrialized nations. The advent of and technical improvements in revascularization and medical therapy have led to a steady decline in mortality rates. However, many patients who suffer unstable angina or myocardial infarction require further testing and risk stratification to guide therapeutic selection and prognosis assignment. Myocardial edema imaging with cardiac magnetic resonance (CMR) affords the ability to define the amount of myocardium at risk, refine estimates of prognosis and provide guidance for therapies with excellent sensitivity compared with standard clinical markers. This review will discuss the rationale for edema imaging, how it is performed using CMR, and potential clinical applications. J. Magn. Reson. Imaging 2011;. © 2011 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Technetium-99m-sestamibi (Tc-MIBI) is a small, lipophilic and cationic compound used for myocardial perfusion imaging. In addition, Tc-MIBI has been shown to be useful in identifying several types of tumors, such as breast, lung and thyroid cancers. The high quality of this radiopharmaceutical and its uniformity are very important facts for application of this preparation in clinical practice. The monograph for Tc-MIBI recommends at least 90% radiochemical purity (RCP) for clinical use. Various factors may influence the RCP of certain reagent kits. Some of these include the amount of activity added to the reagent kit, heating time and the age of the formulated kit. The effect of these factors on RCP of Tc-MIBI has been investigated using high performance liquid chromatography (HPLC) and instant thin layer chromatography. [ABSTRACT FROM AUTHOR]

Although acute myocardial infarction (AMI) is still one of the main causes of high morbidity in Western countries, the rate of mortality has decreased significantly. The main cause of this drop appears to be the decline of the incidence of ST-segment elevation myocardial infarction (STEMI) along with an absolute reduction in case fatality rate once STEMI has occurred. Myocardial ischaemia progresses with the duration of coronary occlusion and the delay in time to reperfusion determines the extent of irreversibile necrosis from subendocarial layers towards the epicardium in accordance with the so-called ‘wave-front phenomenon’. Coronary artery recanalization, either by thrombolitic therapy or primary percutaneous intervention, may prevent myocardial cell necrosis increasing salvage of damaged, but still viable, myocardium within the area at risk. Magnetic resonance imaging (MRI) can provide a wide range of clinically useful information in AMI by detecting not only location of transmural necrosis, infarct size and myocardial oedema, but also showing in vivo important microvascular pathophysiological processes associated with AMI in the reperfusion era, such as intramyocardial haemorrhage and no-reflow. The focus of this review will be on the impact of cardiac MRI in the characterization of AMI pathophysiology in vivo in the current reperfusion era, concentrating also on clinical applications and future perspectives for specific therapeutic strategies. [ABSTRACT FROM PUBLISHER]

99mTc-sestamibi has been proposed as a viability imaging agent. The purposes of this study were: (1) to determine the relationship between myocardial viability and 99mTc-sestamibi kinetics using perfused rat heart models across a full spectrum of viability, (2) to do so under conditions where myocardial flow was controlled and held constant, and (3) to do so using multiple quantitative methods to assess myocardial viability. Twenty-three isolated rat hearts were perfused retrogradely with a modified Krebs-Henseleit (KH) solution. Four groups were studied: controls (C, n = 6), stunned (S, n = 6), ischemic-reperfused (IR, n = 6), and calcium injured (CAL, n = 5). Following a 20-min baseline and subsequent treatment phase, 99mTc-sestamibi was infused over 60 min (uptake) followed by 60 min clearance. Treatment phases consisted of 20 min no flow for S, 60 min no flow followed by 60 min reflow for IR, and 10 min infusion of KH solution without calcium followed by 20 min infusion of KH solution with 2 times normal calcium for CAL hearts. Creatine kinase (CK) assay, triphenyltetrazolium chloride (TTC) staining, and transmission electron microscopic (TEM) analysis were used to determine tissue viability. Myocardial peak 99mTc-sestamibi uptake (%id) was significantly decreased in IR (4.11 ± 0.22 SEM; p < 0.05) and CAL (1.07 ± 0.13; p < 0.05), but not in S (4.88 ± 0.17) as compared with C (5.99 ± 0.50). One hour fractional retention was 79.3 ± 1.9% for C, 80.3 ± 1.3% for S ( p = n.s.), 79.1 ± 1.8% for IR ( p = n.s.), and 14.9 ± 4.3% for CAL ( p < 0.05 compared to all other groups). 99mTc-sestamibi absolute retention (%id) 1 h after the end of tracer administration was significantly decreased in IR (3.26 ± 0.23) and CAL (0.15 ± 0.02) as compared with both S (3.92 ± 0.16) and C (4.52 ± 0.32) ( p < 0.05). CK increased significantly from baseline in the IR and CAL hearts. TTC determined percent viability was 100 ± 0% for C, 98.3 ± 1.1% for S, 82.8 ± 2.6% for IR, and 0.0 ± 0% for CAL. TEM analysis supported these findings. End tracer activity was significantly correlated with TTC determined percentage viable myocardium ( r = 0.93, p < 0.05) and CK leak ( r = −0.90, p < 0.05). 99mTc-sestamibi myocardial activity is significantly reduced in areas of nonviability after 1 h of tracer uptake and 1 h of tracer clearance. There is a linear correlation between myocardial viability, as determined by three independent methods, and tracer activity. [ABSTRACT FROM AUTHOR]

Immediate reopening of acutely occluded coronary arteries via primary percutaneous coronary intervention (PCI) is the treatment of choice to salvage the ischemic myocardium in the setting of ST-segment elevation myocardial infarction (STEMI). However, the sudden re-initiation of blood flow achieved with PCI can lead to a local acute inflammatory response with further endothelial and myocardial damage.This phenomenon, described as ‘reperfusion injury’, has been recognized for several decades, yet no pharmacologic intervention has so far succeeded in reducing myocardial damage linked to reperfusion. FX06 is a naturally occurring peptide derived from the neo-N-terminus of fibrin (Bβ15–42). It prevents leukocyte migration through the gap junctions of endothelial cells. Experimental studies have shown that FX06 inhibits the binding of the proinflammatory fibrin E1 fragment to VE-cadherin expressed in the adherence junction. It represents a novel approach to reducing local and systemic inflammation, including myocardial reperfusion injury, in the adherens junction. The present multicenter, double-blind, randomized, placebo-controlled study is designed to test the hypothesis that FX06 injection during and immediately after primary PCI can reduce infarct size in patients with STEMI. The primary outcome measure of efficacy in this study is the degree of myocardial salvage calculated as the difference between the perfusion defect before and after PCI, determined by myocardial perfusion scintigraphy during rest. Further, infarct size at the end of the index hospitalization, as well as at 4 months, will be measured by cardiac magnetic resonance imaging. The present position paper describes the rationale, design and the methods utilized in this trial. Copyright © 2007 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Aims The last guidelines recommend a standardized 17-segment model for tomographic imaging of the left ventricle. The aim of this study is to analyse the correspondence of the 17 left ventricular segments with each coronary artery by myocardial perfusion SPECT studies. [ABSTRACT FROM PUBLISHER]

Aims It is unclear whether the protection observed in human heart following repetition of brief episodes of ischaemia is due to opening of coronary collaterals or to ischaemic preconditioning. We investigated whether the improvement in ST segment change following repeated episodes of brief ischaemia during coronary angioplasty is due to preconditioning when the size of the area at risk and the collateral flow are taken into account. Methods and results Thirty-six patients underwent percutaneous transluminal coronary angioplasty. Intracoronary ST segment changes were measured throughout the procedure and used as an endpoint. The size of the area at risk and the collateral perfusion within the ischaemic bed were measured using single photon emission computerized tomography (SPECT). Conclusion These results suggest that ischaemic preconditioning does occur during repeated brief coronary artery occlusion in the human heart. [ABSTRACT FROM PUBLISHER]

During placement of a central venous catheter (CVC), the vessel dilator and/or combination dilator/sheath-introducer are recognized as potential causative agents in numerous traumatic complications that may be erroneously ascribed to the catheter, placement needle, or guidewire. A review of the literature and device-user survey are offered in support of the need for additional training in safe dilator use, as well as the need to address device labeling and device design. [ABSTRACT FROM AUTHOR]

Abstract. Acceptance of technetium-99m sestamibi as a tracer of myocardial viability is growing, particularly when nitrate-enhanced imaging is used. However, few data are available on the ability of [sup 99m]Tc-sestamibi to predict the evolution of global left ventricular ejection fraction (EF). The aim of this study was to examine the ability of resting and nitrate [sup 99m]Tc-sestamibi single-photon emission tomography (SPET) to predict EF changes after revascularisation in patients who have chronic coronary artery disease with left ventricular dysfunction. Using baseline resting and nitrate [sup 99m]Tc-sestamibi SPET, we studied 61 patients scheduled for revascularisation because of left ventricular dysfunction. EF was estimated using two-dimensional echocardiography before and after the intervention. A post-revascularisation improvement of is greater than or equal to 5 EF units was defined as significant. Using a 13-segment model, [sup 99m]Tc-sestamibi activity was quantified and the nitrate-induced activity changes calculated. Three different criteria for detecting viability (defined as post-revascularisation reversible dysfunction) in asynergic segments were compared: (1) resting [sup 99m]Tc-sestamibi activity is greater than or equal to 60%; (2) nitrate [sup 99m]Tc-sestamibi activity is greater than or equal to 65%; and (3) nitrate-induced increase >+10% or nitrate-induced increase less than or equal to +10% and nitrate activity is greater than or equal to 65%. EF increased significantly in 32... [ABSTRACT FROM AUTHOR]

Myocardial uptake of technetium-99m sestamibi at low coronary flow rates overestimates blood flow, but the relative impact of flow and viability on 99mTc-sestamibi kinetics is unclear. The objective of this study was to determine the effect of myocardial viability and the degree of collateral blood flow on the uptake and retention of 99mTc-sestamibi by examining three animal models of coronary occlusion and reperfusion, each reflecting a different state of viability and collateral blood flow. Three closed-chest animal models were studied: canine (high collateral flow, preserved viability), porcine (low collateral flow, absent viability) and porcine with slowly occlusive coronary stents producing infarction and enhanced collateral blood flow (high collateral flow, absent viability). There were seven dogs, seven pigs and six pigs, respectively, in each animal model. Animals from all three models were subjected to a 40-min total left anterior descending artery (LAD) occlusion followed by 2 h of reperfusion. 99mTc-sestamibi and radiolabelled microspheres were injected during LAD occlusion 10 min prior to reperfusion. Animals were sacrificed after 2 h of reperfusion flow. Ex situ heart slice imaging to determine risk area was followed by viability staining to determine infarct size. Slices were subsequently sectioned into equally sized radial segments and placed in a gamma well counter. Risk area as determined by ex situ 99mTc-sestamibi imaging was not significantly different by model. Pathological infarct size differed significantly by model [canine = 1%±1% of the left ventricle (LV); porcine = 13%±8% LV; porcine with stent = 14%±7% LV; P=0.002)]. Collateral blood flow by microspheres during occlusion tended to differ among models (overall P=0.08), with the canine and porcine with stent models having relatively high flow rates compared with the acute porcine model. 99mTc-sestamibi activity correlated with microsphere blood flow in all three models, with r values for individual animals ( n=20) ranging from 0.86 to 0.96 (all P<0.0001). There was a significant difference in the regression line intercepts (P<0.0001) and slopes (P<0.01) among the three models comparing 99mTc-sestamibi uptake with myocardial blood flow. 99mTc-sestamibi uptake overestimated blood flow to a greater extent in the canine model (high flow with viability) than in the porcine model (low flow, absent viability). Despite enhanced collateral flow, there was significantly less overestimation of flow in the porcine stent model (high flow, absent viability). In conclusion, at low flow rates 99mTc-sestamibi activity overestimates myocardial blood flow. This effect is most pronounced in myocardium with significant collateral flow and preserved viability, consistent with over-extraction or redistribution of the tracer. The effect is markedly decreased in non-viable myocardium regardless of blood flow. [ABSTRACT FROM AUTHOR]

Manufacturers of in vitro diagnostic (IVD) medical devices have become integral partners with their customers in determining the quality of laboratory results. Design controls imposed by ISO 9001 quality system standards and various regulations require manufacturers to implement a formal design process, which begins and ends with customer requirements. For IVD systems, this means that manufacturers must establish analytical quality specifications as part of their design input. This provides greater assurance that commercial products will satisfy customer requirements. In the case of quantitative IVD measurement systems, analytical quality specifications include total allowable uncertainty (bias, imprecision, non-specificity). The primary source of customer requirements is the laboratory-customer, who should have established analytical quality specifications based on the needs of its physician-clients. The total allowable uncertainty budget is allocated in the design process to the individual components of the system, such as reagents, instrumentation, calibrators and accessories, and to other factors such as operator, specimen and environmental interactions. Their performance must collectively meet the total allowable uncertainty specification when they are finally integrated into a measurement system. The design control model requires objective evidence that design specifications have been met (verification) and, finally, that the system will satisfy the needs of its intended users (validation). Compliance with the quality system standards is monitored through independent audits, government inspections and post-market surveillance. [ABSTRACT FROM AUTHOR]

Rest technetium-99m sestamibi single-photon emission tomography (SPET) has been shown to under-estimate viability in some patients with chronic ischaemic myocardial dysfunction. The present study was designed to appraise the value ofTc-sestamibi as a viability tracer in patients with a recent myocardial infarction and to determine factors that might influence its accuracy in assessing infarct size. Therefore, restTc-sestamibi SPET, low-dose dobutamines stress echocardiography and quantitative coronary angiography were performed in 51 patients with a recent myocardial infarction. Perfusion activity and regional wall motion were scored semi-quantitatively using the same segmental division of the left ventricle. Assessment ofTc-sestamibi uptake as a marker of viability was performed by comparing a binary uptake score (viable=>50% vs necrotic =≤50% of the maximal tracer activity) with a binary wall motion classification during low-dose dobutamine infusion (viable=normal/hypokinetic vs necrotic=akinetic/dyskinetic). Infarct size, expressed as the number of segments with evidence of necrotic tissue, was significantly greater in the scintigraphic study than in the echocardiographic study (2.8±1.5 vs 2.2±1.3, P=0.006). This overestimation of infarct size byTc-sestamibi was present only in patients with a severe infarct-related stenosis (% diameter stenosis ≽65%-100%) and particularly those with 'late' reperfusion therapy (time delay ≽180 min). In patients without a severe infarct-related stenosis,Tc-sestamibi was able to accurately distinguish viable from necrotic segments. Thus, restTc-sestamibi scintigraphy early after acute myocardial infarction may underestimate residual viability within the infarct region, particularly in patients with low flow state coronary anatomy, as a result of a severe infarct-related stenosis and/or late reperfusion therapy. [ABSTRACT FROM AUTHOR]

The purpose of the current study was to clarify the myocardial kinetics of technetium-99m sestamibi when the latter is administered during reperfusion. Sestamibi has in the past been given to patients following thrombolytic therapy to document reperfusion and assess salvage. However, the factors which affect sestamibi kinetics during reperfusion are not clearly defined. In this study the left circumflex coronary artery was occluded for 2 h in six dogs (group 1) and for 3 h in six dogs (group 2), followed by reperfusion. Five additional dogs were not reperfused (group 3). Sestamibi was administered during reperfusion in groups 1 and 2, and during ongoing occlusion in group 3. Regional myocardial sestamibi activity was monitored for 3 h using miniature implanted radiation detectors and gamma camera imaging. Group 1 dogs had no infarcts, group 2 had moderate infarcts (mean: 13.9%), and group 3 had large infarcts (mean: 25.2%). Three-hour fractional myocardial clearances were significantly greater for reperfused infarcted (group 2) (0.23±0.02 SEM) and for nonreperfused infarcted myocardium (group 3) (0.24±0.02) compared to control (0.10±0.01) and reperfused non-infarcted myocardium (group 1) (0.07±0.02; P<0.01). Quantitative image analysis demonstrated a significant reduction in the left circumflex/left anterior descending count ratios from initial to final scans for group 2 (0.74±0.03 to 0.65±0.03, P<0.05), and a trend towards a reduction in the count ratios from initial to final scans for group 3 (0.38±0.04 to 0.30 ±0.04; P = 0.06). Thus, probe-derived myocardial sestamibi kinetics following reperfusion do differentiate non-infarcted from infarcted myocardium. Although the detection of accelerated clearance can be demonstrated by quantitative analysis of gamma camera images in dogs, this may be technically difficult in clinical situations. [ABSTRACT FROM AUTHOR]

This study investigated the mechanism of myocardial retention of technetium-99m-sestamibi.Tc-sestamibi was injected intravenously into guinea pigs, and the myocardium was homogenized and fractionated by differential centrifugation. More than 90% of myocardialTc-sestamibi was localized within the mitochondrial fraction. Calcium was found to releaseTc-sestamibi from the mitochondrial fraction, with an IC of 2.54±0.98 mM. This effect was potentiated by NaCl, and inhibited by the mitochondrial calcium channel blocker ruthenium red. In vitro uptake ofTc-sestamibi was found to increase from 10.5% ± 3.0% to 61.2% ± 0.2% with the addition of 10 mM succinate, indicating that respiration is involved. Since irreversible ischemia results in cellular and mitochondrial calcium 'overload' and loss of mitochondrial metabolic function,Tc-sestamibi should not be retained in necrotic or irreversibly ischemic myocardium, and could potentially act as a sensitive indicator of myocardial cell viability. [ABSTRACT FROM AUTHOR]