Association of Alcohol Consumption with Cognition and Functionality in Older Adults Aged 75+ Years: The Pietà Study.

The relationship between alcohol consumption and cognition is still controversial. This is a cross-sectional population-based study conducted in Caeté (MG), Brazil, where 602 individuals aged 75+ years, 63.6% female, and with a mean education of 2.68 years, were submitted to thorough clinical assessments and categorized according to the number of alcoholic beverages consumed weekly. The prevalence rates of previous and current alcohol consumption were 34.6% and 12.3%, respectively. No association emerged between cognitive diagnoses and current/previous alcohol consumption categories. Considering current alcohol intake as a dichotomous variable, the absence of alcohol consumption was associated with dementia (OR = 2.34; 95%CI: 1.39-3.90) and worse functionality (p = 0.001). Previous consumption of cachaça (sugar cane liquor) increased the risk of dementia by 2.52 (95%CI: 1.25-5.04). The association between the consumption of cachaça and dementia diagnosis has not been described before.

Ultrasound biomicroscopy in the quantification of brain perfusion parameters of a rat stroke model: Analysis of contrast agent bolus kinetic dynamics.

BACKGROUND: Ischemic stroke represents a significant global health concern, necessitating thorough investigations and the utilization of stroke animal models to explore novel treatment modalities and diagnostic imaging techniques. NEW METHOD: Ultrasound biomicroscopy (BMU), operating at a center frequency of 21 MHz, along with ultrasound contrast agents (UCAs), was used to quantify microcirculation cerebral blood flow in a rat model of ischemic stroke. The microcirculation parameters were derived from time intensity curve (TIC) plots obtained based on UCA-bolus kinetics. RESULTS: Semiquantitative perfusion-related parameters were assessed. The TIC curves showed differences in amplitude when compared intra-animal between the left and right sides, and three situations were observed: normal perfusion, hypoperfusion, and nonperfusion. ROC analysis of delays between the left and right time intensity peak (TIP) for regions of interest (ROIs) in the control and stroke-hypoperfusion groups revealed an optimal cutpoint of 0.39 s to indicate when hypoperfusion is occurring in rats, with a sensitivity of 93.33 % and a specificity of 80 %. COMPARISON WITH EXISTING METHOD(S): Ultrasound perfusion imaging through the temporal bone window has been clinically applied to stroke patients using a UCA bolus for TIC analysis. TIC parameters were correlated with MRI- and CT-based measurements. CONCLUSIONS: This investigation quantified cerebral blood flow in a rat model of ischemic stroke by measuring microcirculation parameters. The study demonstrated the efficacy of this approach as a valuable tool for conducting preclinical studies.

Clinical and functional correlates of parkinsonism in a population-based sample of individuals aged 75 + : the Pietà study.

BACKGROUND: Parkinsonism is strongly associated with ageing, and many studies have suggested that parkinsonian signs may affect up to half of older adults and is associated with a wide range of adverse health outcomes. We compared clinical and functional characteristics of oldest-old community-dwelling individuals with parkinsonism (parkinsonian group [PG]) to individuals without parkinsonism (non-parkinsonian group [NPG]. METHODS: The Pietà study is a population-based study conducted in Caeté, southeast Brazil, involving 607 individuals aged 75 + years submitted to an extensive clinical evaluation. A subset of 65 PG individuals (61.5% women, median age of 82 years) was compared to 542 NPG individuals (64.8% women, median age of 80 years). RESULTS: PG individuals had significantly more functional impairment, clinical comorbidities (including number of falls, loss of bladder control and dysphagia) and major depression. Multivariate analysis revealed that older age, higher UPDRSm scores, lower category fluency test (animals/minute) and delayed recall memory scores were associated with PG. This group was also more cognitively impaired, with lower performance than NPG individuals in the Mini-Mental State Examination, category fluency test (animals/minute), clock drawing and in delayed recall (p < 0.001 for all tests). UPDRSm scores were the most contributing factor to cognition that independently explained variability in functionality of the entire sample. CONCLUSION: Individuals aged 75 + years with parkinsonism were significantly more clinically and functionally impaired in this population-based sample. Cognitive dysfunction explained most of the loss of functionality in these patients. UPDRS-m scores contributed independently to explain variability in functionality in the whole sample.

Ultrasound biomicroscopy for the assessment of early-stage nonalcoholic fatty liver disease induced in rats by a high-fat diet.

PURPOSE: The aim of this study was to assess the ability of ultrasound biomicroscopy (UBM) to diagnose the initial stages of nonalcoholic fatty liver disease (NAFLD) in a rat model. METHODS: Eighteen male Wistar rats were allocated to control or experimental groups. A high-fat diet (HFD) with 20% fructose and 2% cholesterol, resembling a common Western diet, was fed to animals in the experimental groups for up to 16 weeks; those in the control group received a regular diet. A 21 MHz UBM system was used to acquire B-mode images at specific times: baseline (T0), 10 weeks (T10), and 16 weeks (T16). The sonographic hepatorenal index (SHRI), based on the average ultrasound image gray-level intensities from the liver parenchyma and right renal cortex, was determined at T0, T10, and T16. The liver specimen histology was classified using the modified Nonalcoholic Steatohepatitis Clinical Research Network NAFLD activity scoring system. RESULTS: The livers in the animals in the experimental groups progressed from sinusoidal congestion and moderate macro- and micro-vesicular steatosis to moderate steatosis and frequent hepatocyte ballooning. The SHRI obtained in the experimental group animals at T10 and T16 was significantly different from the SHRI of pooled control group. No significant difference existed between the SHRI in animals receiving HFD between T10 and T16. CONCLUSION: SHRI measurement using UBM may be a promising noninvasive tool to characterize early-stage NAFLD in rat models.

The P2X7 Receptor Promotes Colorectal Inflammation and Tumorigenesis by Modulating Gut Microbiota and the Inflammasome.

Background: Given the role of the P2X7 receptor (P2X7R) in inflammatory bowel diseases (IBD), we investigated its role in the development and progression of colitis-associated colorectal cancer (CA-CRC). Methods: CA-CRC was induced in P2X7R+/+ and P2X7R-/- mice with azoxymethane (AOM) combined with dextran sodium sulfate (DSS). In a therapeutic protocol, P2X7R+/+ mice were treated with a P2X7R-selective inhibitor (A740003). Mice were evaluated with follow-up video endoscopy with endoluminal ultrasound biomicroscopy. Colon tissue was analyzed for histological changes, densities of immune cells, expression of transcription factors, cytokines, genes, DNA methylation, and microbiome composition of fecal samples by sequencing for 16S rRNA. Results: The P2X7R+/+ mice displayed more ulcers, tumors, and greater wall thickness, than the P2X7R-/- and the P2X7R+/+ mice treated with A740003. The P2X7R+/+ mice showed increased accumulation of immune cells, production of proinflammatory cytokines, activation of intracellular signaling pathways, and upregulation of NLRP3 and NLRP12 genes, stabilized after the P2X7R-blockade. Microbial changes were observed in the P2X7R-/- and P2X7R+/+-induced mice, partially reversed by the A740003 treatment. Conclusions: Regulatory mechanisms activated downstream of the P2X7R in combination with signals from a dysbiotic microbiota result in the activation of intracellular signaling pathways and the inflammasome, amplifying the inflammatory response and promoting CA-CRC development.

Shear Elastic Coefficient of Normal and Fibrinogen-Deficient Clotting Plasma Obtained with a Sphere-Motion-Based Acoustic-Radiation-Force Approach.

Blood coagulation is a process involving several chemical reactions governed by coagulation factors, during which the shear elastic coefficient, µ, varies as the medium transitions from liquid to gel phase. This work used ultrasound to measure µ during the clotting of human plasma samples by tracking the motion of a glass sphere located inside a cuvette filled with the plasma. A 2.03 MHz ultrasonic system generated an impulsive acoustic radiation force acting on the sphere, and a 4.89 MHz pulse-echo ultrasonic system tracked the sphere displacement induced by that force. Measurements of µ were determined by fitting a µ-dependent theoretical model to the motion waveform of the sphere immersed in clotting normal plasma and plasma samples with fibrinogen (FI) concentrations of 1.2 (FI-deficiency) and 3.6 (FI-normal) g/L. For normal plasma, µ started at 14.22 Pa and increased rapidly until 2 min, then slowly until it reached 210.23 Pa at 35 min after the clotting process started. A similar trend was exhibited in plasma samples with FI concentrations of 1.2 and 3.6 g/L, with µ reaching 120.55 and 679.42 Pa, respectively. A theoretical model, related to the kinetics of clot-structure formation, describes the time changes of µ for the clotting plasma samples. The sphere-motion-based acoustic-radiation-force approach allowed us to measure the shear elastic coefficient during the coagulation process of plasma samples with normal and deficient FI concentrations. Our results suggest that the method used in this study is capable of being used to detect bleeding disorders.

3-D Endoluminal Ultrasound Biomicroscopic Imaging and Volumetry of Mouse Colon Tumors.

Currently, colonoscopy is considered the gold standard procedure for diagnosis of colorectal cancer (CRC), the third most common cancer in the United States. However, this technique fails to detect flat adenomas, serrated polyps and advanced adenomas, with miss rates of 34%, 27% and 14%, respectively. These miss rates, more frequent than previously supposed, suggest the need for new CRC screening tools. In the work described here, the potential application of a 40-MHz ultrasound system to generate a sequence of 2-D endoluminal ultrasound biomicroscopy (eUBM-2-D) images of a mouse model of colon cancer was investigated, and this image sequence was used to render eUBM-3-D images and to measure tumor volume. The technique was validated with tissue-mimicking phantoms and used in vivo with mice bearing colon polypoid tumors. Estimated volumes ranged from 0.174-7.909 mm3 for targets in validation phantoms and from 0.066-6.082 mm3 for mouse colon tumors.

Dynamic assessment of plasma clotting in samples with distinct fibrinogen concentrations using impulsive acoustic radiation force.

While some diseases reduce fibrinogen concentration, others increase the amount of this clotting factor in the blood. Some studies have shown that the fibrinogen concentration in the blood is related to the stiffness of the formed clot. Hence, the aim of this study was to employ an ultrasonic method based on impulsive acoustic radiation force (IARF) to identify the fibrinogen concentration (coagulation factor I) in a plasma sample by means of peak-displacement (PD), time of peak-displacement (TPD), and shear modulus (µ) as well as to identify the change of plasma samples during the clot formation process. The IARF-based ultrasonic system transmitted bursts with a frequency of 2.03 MHz, duration of 246.31 µs, amplitude of 118 VPP, and pulse with 1.25 Hz repetition frequency to generate an IARF on a glass sphere (2.99 mm in diameter and 2500 kg/m3 in density) embedded in a plasma sample, causing a displacement that was monitored by a pulse-echo system with a center frequency of 4.89 MHz. The values of the shear moduli were 124.14 ± 3.02, 556.99 ± 11.76, and 670.39 ± 9.77 Pa, for fibrinogen concentrations of 1.2, 2.4, and 3.6 g/L 20 to 36 min after the beginning of the coagulation process. The TPD values obtained in the same period were 5.28 ± 0.09, 3.03 ± 0.02, and 2.83 ± 0.01 s. The results indicate that an IARF-based ultrasonic system can be used clinically because it uses small amounts of plasma and has the ability to detect differences in PD, TPD, and µ as a function of fibrinogen concentrations.

Diabetes and impaired fasting glucose in a population-based sample of individuals aged 75 + years: associations with cognition, major depressive disorder, functionality and quality of life-the Pietà study.

OBJECTIVES: To investigate the rates of diabetes mellitus (DM) and impaired fasting glucose (IFG) in a population-based sample of individuals aged 75 + years old and their associations with cognitive performance, depression, functionality, and quality of life (QoL). STUDY DESIGN: Overall, 350 people participated in the study. Assessments of cognition, mood, functionality and QoL were performed using the mini-mental state examination (MMSE), clock-drawing, category fluency tests, the Mini-International Neuropsychiatric Interview, Pfeffer's Functional Activities Questionnaire, and the WHO Quality of Life-Old (WHOQOL-OLD). RESULTS: IFG (ADA criteria) was identified in 42.1% of the sample, while the DM rate was 24.1%. Lack of knowledge of the DM diagnosis and lack of treatment occurred in 27% and 39% of the sample, respectively. Rates of dementia and depression, MMSE, category fluency scores, and previous cardiovascular events did not differ between the glycaemic groups. Individuals with DM performed worse on the clock-drawing test, functionality, and WHOQOL-OLD than the other participants. Individuals with IFG presented similar QoL and functionality when compared with the group without DM. CONCLUSIONS: IFG and DM were common in this population-based sample aged 75 + years old, as were inadequate diagnoses and treatments of DM. DM individuals presented poor performance in the executive function test, functionality, and QoL. Further studies are recommended to investigate the value of an IFG diagnosis among the most elderly population.

The influence of age, sex and education on the phenomenology of depressive symptoms in a population-based sample aged 75+ years with major depression: the Pietà Study.

OBJECTIVES: Late-life depression (LLD) is the most common mental disorder among the elderly, but its clinical features remain unclear, especially among older adults. We sought to investigate if age, sex and education could influence the severity or frequency of LLD symptoms. METHODS: We evaluated 639 community-dwelling individuals aged 75+ years in Caeté (MG), Brazil. We used the Mini International Neuropsychiatric Interview to diagnose major depression according to DSM-IV criteria and the GDS-15 to measure depression severity. RESULTS: Excluding 174 individuals diagnosed with dementia, 54 (11.6%) of the remaining 457 individuals were diagnosed with LLD; 77.8% of which were female. On average, these participants were aged 81.0 ± 4.8 years and had 2.7 ± 3.3 years of schooling. Symptom severity was not influenced by sociodemographic variables. Death/suicidal ideation was more frequent among men, while psychomotor disturbance was more present in women (p = 0.04 and p = 0.042). More educated individuals (≥ 4 years) also reported a higher frequency of psychomotor disturbance (p = 0.039). CONCLUSIONS: Severity of depressive episode was not influenced by sociodemographic variables. Sex and educational level had a significant impact on symptom profiles.

Detection of Mice Colorectal Tumors by Endoluminal Ultrasound Biomicroscopic Images and Quantification of Image Augmented Gray Values Following Injection of VEGFR-2 Targeted Contrast Agent.

RATIONALE AND OBJECTIVES: Ultrasound biomicroscopy (UBM) is a noninvasive imaging technique that can be applied in detecting colonic tumors and, once associated with an ultrasound contrast agent (UCA), can identify the molecular expression of cancer-related biomarkers, such as the vascular endothelial growth factor receptor 2 (VEGFR-2). The present work aimed to detect colonic tumors and quantify augmented gray values of endoluminal UBM (eUBM) images from colonic tumors following the injection of VEGFR-2 targeted UCA (VEGFR2-UCA) into a mouse model of colorectal cancer. MATERIAL AND METHODS: A 40 MHz miniprobe catheter inserted through the biopsy channel of a pediatric flexible bronchofiberscope was used to obtain colonoscopic and B-mode eUBM images simultaneously. Seventeen tumor-bearing mice had their colons inspected and six of them were subjected to a VEGFR2-UCA injection to predict VEGFR-2 expression. RESULTS: All animals developed distal colon tumors and eUBM was able to detect all of them and also to characterize the tumors, with 71.4% being in situ lesions and 28.6% being tumors invading the mucosa + muscularis mucosae + submucosa layers, as confirmed by histopathology. After VEGFR2-UCA injection, gray values from the eUBM tumoral images increased significantly (p < 0.01). Tumor sites with increased eUBM image gray values corresponded to areas with increased VEGFR-2 expression, as confirmed by immunohistochemistry. CONCLUSION: The results confirm eUBM as a powerful noninvasive and real-time tool for detecting colon tumor and its invasiveness and once associated with VEGFR2-UCA may become a tool for the detection of VEGFR-2 expression in colonic tumors.

Temperature estimation of inflamed bowel by the photoacoustic inverse approach.

Local temperature increase is one of the five classical signs of regions with inflammations. This work is focused on the application of the photoacoustic technique for the estimation of the temperature field in the colon, as the solution of an inverse problem, for the detection of inflamed regions. Two-dimensional cases are examined here involving a cross section of the bowel, which characterize either the inflammation of the whole mucosa layer, or three small inflamed regions. The inverse problem is solved for a rotating laser inside the intestine lumen, which imposes pulses for the generation of the acoustic waves. One single ultrasound detector, also located at the laser rotating shaft, provides the simulated measurements for the inverse analysis. The inverse problem is solved here with the minimization of the maximum a posteriori objective function. Results show that the proposed technique can be applied for accurate estimations of the temperature distribution in the region of interest, which might be used for the diagnosis of inflammatory bowel diseases (IBD).

Prevalence of late-life depression and its correlates in a community-dwelling low-educated population aged 75+ years: The Pietà study.

BACKGROUND: The number of individuals with advanced age is growing worldwide, especially in developing countries. Depression is the most common mental disorder in the elderly. The aim of this study was to evaluate the prevalence rates and the correlates of late-life depression (LLD) and clinically significant depressive symptoms (CSDS) in a population aged 75+ years. METHODS: We evaluated 639 community-dwelling individuals aged 75+ years in Caeté (MG), Brazil, and used the MINI to diagnose LLD according to DSM-IV criteria and the GDS-15 to identify CSDS. Quality of life was assessed by the WHOQOL-OLD scale. RESULTS: Overall, 639 individuals (64% female, with a mean age of 81.1 ±â€¯5.2 and 2.6 ±â€¯2.8 years of schooling) were evaluated; 70 (11.1%) were diagnosed with LLD and 146 (25.6%) with CSDS. Depressed subjects (both with LLD and CSDS) had poorer measures of quality of life. Logistic regression analyses showed that LLD was independently associated to a history of falls/fracture, a diagnosis of cognitive impairment-no dementia, the number of regular drugs used, lack of reading habit and, inversely, to systolic blood pressure. LIMITATIONS: The use of MINI which has not been validated in the elderly. No information was available on the number of previous depressive episodes or on the age of first episode. CONCLUSION: Both dimensional and categorical diagnoses of depression were prevalent among community-dwelling oldest-old individuals. Different clinical and personal variables were associated with depression, which negatively influenced the quality of life of the affected individuals.

Parkinsonism in a population-based study of individuals aged 75+ years: The Pietà study.

INTRODUCTION: Parkinsonism is one of the most prevalent neurological syndromes in the elderly. There are only a few epidemiological studies focusing on parkinsonism in oldest-old individuals, particularly in Latin America. This study aims to investigate the prevalence and characteristics of parkinsonism in subjects aged 75 + years living in the community. METHODS: The Pietà study is a population-based investigation on brain aging conducted in Caeté, southeast Brazil. A sample composed of 610 community-dwelling individuals aged 75 + years (48.7% of the total population within this age range) underwent clinical, neurological, cognitive and functional assessments. RESULTS: The sample comprised mostly women (61.5%), with mean age of 83.3 years and mean schooling of 2.5 years. Parkinsonism was identified in 65 subjects (crude prevalence = 10.7%). Parkinson's disease, Parkinsonism + dementia syndrome, drug-induced parkinsonism, vascular parkinsonism and Lewy-body dementia were identified in, respectively, 19 (29.2%), 19 (29.2%), 8 (12.3%), 4 (6.1%) and 1 (1.5%) subjects. In 14 individuals (21.5%), the etiology of parkinsonism could not be determined. The most important vascular risk factor was hypertension (64.6%). Cognitive evaluation disclosed dementia in 37 (56.9%) subjects. Mean Pfeffer's functional activities questionnaire score was 12.2 points and 22 (33.8%) subjects were impaired in basic activities of daily living. CONCLUSION: Parkinsonism was common in this oldest-old population, being associated with dementia and vascular risk factors, particularly hypertension. Different confounders, such as concomitant dementia and exposure to anti-dopaminergic drugs, were present in this population, challenging the definition of causes of parkinsonism.

Ultrasonic method of microvibration detection: part II - additional processing method and applications

Abstract Introduction In the last 28 years, the scientific community has been using elastography to evaluate the mechanical properties of biological tissue. The aim of this work was the optimization of the UDmV method, presented in Part I of the series, by means of modifying the technique employed to generate the reference sine and cosine functions, used for phase-quadrature demodulation, and determining how this modification improved the performance of the method. Additionally, the UDmV was employed to characterize the acoustic and mechanical properties of a 7% gelatin phantom. Methods A focused transducer, T F, with a nominal frequency of 2.25 MHz, was used to induce the shear waves, with frequency of 97.644 Hz. Then, the modified UDmV method was used to extract the phase and quadrature components from ultrasonic RF echo-signals collected from four positions along the propagation path of the shear wave, which allowed the investigation of the medium vibration caused by wave propagation. The phase velocity, c s, and attenuation, α s, of the phantom were measured and employed in the calculation of shear modulus, μ, and viscosity, η. Results The computational simulation demonstrated that the modification in UDmV method resulted in more accurate and precise estimates of the initial phases of the reference sinusoidal functions used for phase-quadrature demodulation. The values for c s and μ of 1.31 ± 0.01 m·s-1 and 1.66 ± 0.01 kPa, respectively, are very close to the values found in the literature (1.32 m·s-1 and 1.61 kPa) for the same material. Conclusion The UDmV method allowed estimating of the acoustic and viscoelastic parameters of phantom.

Ultrasound biomicroscopy and claudication test for in vivo follow-up of muscle repair enhancement based on platelet-rich plasma therapy in a rat model of gastrocnemius laceration.

PURPOSE: To track the regeneration process of lateral gastrocnemius due to a muscle laceration in rats, and to treatment with plateletrich plasma (PRP). METHODS: Ultrasound (40 MHz) images were used for measuring pennation angle (PA), muscle thickness (MT) and mean pixel intensity, along with claudication scores, of treated (PRPG) and non-treated (NTG) groups of rats. RESULTS: NTG showed a PA increase for the non-injured leg (p<0.05) and a tendency of MT to increase, whereas for PRPG there were no differences. There was a progressive reduction of the claudication score for the PRPG group throughout the entire period, with an immediate difference after seven days (p<0.05), whereas the NTG had a significant reduction only at day 28 (p<0.05). CONCLUSION: It was observed a compensatory hypertrophic response due to the overload condition imposed to healthy leg for NTG that did not occur in PRPG, suggesting an accelerated repair process of the injured leg due to treatment, anticipating its use.

Ultrasound biomicroscopy and claudication test for in vivo follow-up of muscle repair enhancement based on platelet-rich plasma therapy in a rat model of gastrocnemius laceration

PURPOSE: To track the regeneration process of lateral gastrocnemius due to a muscle laceration in rats, and to treatment with plateletrich plasma (PRP). METHODS: Ultrasound (40 MHz) images were used for measuring pennation angle (PA), muscle thickness (MT) and mean pixel intensity, along with claudication scores, of treated (PRPG) and non-treated (NTG) groups of rats. RESULTS: NTG showed a PA increase for the non-injured leg (p<0.05) and a tendency of MT to increase, whereas for PRPG there were no differences. There was a progressive reduction of the claudication score for the PRPG group throughout the entire period, with an immediate difference after seven days (p<0.05), whereas the NTG had a significant reduction only at day 28 (p<0.05). CONCLUSION: It was observed a compensatory hypertrophic response due to the overload condition imposed to healthy leg for NTG that did not occur in PRPG, suggesting an accelerated repair process of the injured leg due to treatment, anticipating its use.

Ischemic cerebrovascular burden evaluated by magnetic resonance imaging in an elderly Brazilian community: The Pietà study.

In developing countries, cardiovascular risk factors are poorly controlled, leading to high prevalence of cerebrovascular diseases. The aim of the study was to evaluate the burden of white matter lesions in magnetic resonance through the Fazekas scale in a population aged 75 + years living in the community, and to investigate possible associations between vascular lesions, cardiovascular risk factors and cognitive status. Subjects were selected from a community-based study on brain aging conducted in Caeté (Minas Gerais state), Brazil. Overall, 177 participants (112 cognitively healthy, 36 with cognitive impairment-no dementia and 29 with dementia), being 108 women, aged 79.3 ± 3.8 years, with 3.1 ± 2.9 years of educational level, underwent a 3 Tesla magnetic resonance scanner with fluid attenuated image recovery acquisition. Severity of white matter lesions was assessed through the Fazekas scale. Severe white matter lesions were present in 31.1% of the whole sample and in 25.0% of the cognitively healthy individuals. A significant association was found between severe white matter lesions and cognitive impairment (OR = 2.20, 95% CI 1.17-6.53; p = 0.021), as well as with hypertension (OR = 1.92, 95% CI 1.03-7.39; p = 0.043). In conclusion, a high prevalence of severe white matter lesions was observed in this elderly Brazilian population sample, and white matter lesions were associated with hypertension and cognitive status. Importantly, the prevalence of white matter lesions was also high in cognitively healthy subjects.

Generation of 3D ultrasound biomicroscopic images: technique validation and in vivo volumetric imaging of rat lateral gastrocnemius

Introduction Ultrasound biomicroscopy (UBM) is a technique for generating high-resolution images, with frequencies from 20 MHz to 100 MHz. For example, it has been used in animal research related to models of injury and diseases that mimic human conditions. With a three-dimensional ultrasound (3D) image system, an organ can be viewed at various angles and the volume estimated, contributing to an accurate diagnosis. This work refers to the generation of 3D-UBM images, employing a 35 MHz ultrasound system, from multiple two-dimensional (2D) images. Phantoms were used to validate the technique and to determine its reliability of volume measurements. Additionally, the technique was used to obtain 3D images of the rat gastrocnemius muscle. Methods Four different phantoms were used and ten acquisition sequences of 2D-images acquired for each one. Thereafter, 5 volume segmentations were performed for each acquisition sequence, resulting in 50 measured volumes for each phantom. The physical volumes of all phantoms were used to validate the technique based on the coefficient of variation (CV) and the intraclass correlation coefficient (ICC). Images of the gastrocnemius muscle were acquired and the partial volume quantified. Results The CV and ICC confirmed the reliability of volume measurements obtained by segmentation. Moreover, cross-sectional 2D images of rat hindlimb were obtained, allowing to identify the gastrocnemius muscle and to partially quantify the muscle volume from 3D images. Conclusion The results indicated that the technique is valid to generate 3D images and quantify the volume of a muscle compatible with the dimensions of a small animal.