Correlation of Measurements From Doppler Ultrasound and Optical Coherence Tomography in Glaucoma.

OBJECTIVES: To relate the changes in ocular structure and hemodynamic response in primary open-angle glaucoma (POAG). METHODS: Patients with POAG (n = 46) and control subjects (n = 53) were recruited. Retinal nerve fiber layer and ganglion cell complex were evaluated using optical coherence tomography (OCT). Blood flow was characterized in ophthalmic artery (OA) and central retinal artery (CRA) using color Doppler ultrasonography (CDU), and resistivity index (RI) was calculated. Measurements from CDU and OCT were statistically correlated and the degree of the association was examined. Receiver operating characteristics was produced based on RI and optimal threshold was determined. RESULTS: In POAG patients, OCT revealed neuronal damage and CDU indicated increased resistance to arterial flow. Flow dynamics correlated negatively with the ocular tissue dimensions, sufficiently establishing an association between the ocular structure and its hemodynamic response. Based on the possibility of indirect POAG diagnosis with CDU, threshold 0.7 for RI of OA yielded 73.9% sensitivity and 77.4% specificity in distinguishing the cases of POAG from the controls. Threshold of 0.66 for RI of CRA, had higher specificity of 83%, but lower sensitivity of 52.1%. CONCLUSIONS: Ocular flow exhibits different characteristics in individuals with POAG than normal. The changes associated with the underlying neuronal structure, suggesting the possibility of a potential new diagnostic biomarker for POAG. This justifies further studies with a larger cohort, examining the ocular flow with CDU in POAG and comparing it against OCT findings for establishing the power of CDU in differential diagnosis or glaucoma progression.

Interference of gadolinium dechelated from MR contrast agents by calcium signaling in neuronal cells of GnRH.

Contrast agents (CAs) used in magnetic resonance imaging (MRI) are produced by chelating the metal gadolinium (Gd) with organic ligand molecules to form stable complexes. But, Gd3+ may dissociate from the CAs and subsequently might become toxic to its environment. Besides toxicity, it might inhibit calcium channels on cell membranes and this action could be detrimental to the cells governing biological development. The aim of this study was to investigate the interference of Gd3+ dechelated from the CAs by calcium signaling in the neuronal cells of gonadotropin-releasing hormone (GnRH), regulating puberty, and sexual development. The study used the mouse GT1-7 cell line as a model system, and Fura-2 based calcium imaging for detecting the interruption of intracellular calcium transport by the extracellular presence of Gd3+ as released from the CAs; gadodiamide and gadoterate meglumine, when the cells were stimulated in vitro culture by exposure to melatonin.The CA gadoterate meglumine interfered minimally with the calcium signaling, and thus its use is preferable in standard MRI exams. The release of Gd3+ from gadodiamide was significant and becomes of great concern as it may impact the neurophysiology of the neuronal cells in general, and gonadotropin production in particular, even in normal patients without nephrogenic systemic fibrosis. The toxicity induced by the influx of dechelated Gd3+ in the neurons of GnRH would have significant implications for puberty and reproductive functions.

Role of intermittent pneumatic compression in the treatment of breast cancer-related lymphoedema: a randomized controlled trial.

OBJECTIVE: To evaluate the role of intermittent pneumatic compression in the treatment of breast cancer-related lymphoedema. DESIGN: Randomized controlled trial. SETTING: Physical medicine and rehabilitation clinic at a university hospital. SUBJECTS: Seventy-six patients with lymphoedema. INTERVENTIONS: Patients were allocated into Group 1 (complex decongestive treatment, n = 38) and Group 2 (complex decongestive treatment + intermittent pneumatic compression, n = 38). The complex decongestive treatment involved skin care, manual lymphatic drainage, compression bandaging, and exercise for 20 sessions. Group 2 additionally received intermittent pneumatic compression. MAIN MEASURES: Quantitative outcomes consisted of volumetric measures prior to and after the treatment. Clinical assessments included severity of pain, heaviness and tightness, disability, grip strength, and depression. RESULTS: Lymphoedema was similar at baseline, but treatments significantly reduced the excess volume (from 373 mL to 203 mL in Group 1 and 379.5 mL to 189.5 mL in Group 2). Percentage excess volumes (PEVs) decreased in both groups. The percentage reduction of excess volume was better in Group 2 than Group 1, but the intergroup difference was not significant. The clinical scores reflected improvements, but the heaviness and tightness read significantly lower in Group 2 than Group 1. CONCLUSION: Intermittent pneumatic compression seems to add no benefit when combined with complex decongestive treatment of lymphoedema, but, may be functional in reducing the sensations of heaviness and tightness for the patients with pitting oedema.

Assessment of infarct-specific cardiac motion dysfunction using modeling and multimodal magnetic resonance merging.

PURPOSE: To propose a cardiac motion tracking model that evaluates wall motion abnormality in postmyocardial infarction patients. Correlation between the motion parameter of the model and left ventricle (LV) function was also determined. MATERIALS AND METHODS: Twelve male patients with post-ST elevation myocardial infarction (post-STEMI) and 10 healthy controls of the same gender were recruited to undergo cardiac magnetic resonance imaging (MRI) using a 1.5T scanner. Using an infarct-specific LV division approach, the late gadolinium enhancement (LGE) MRI images were used to divide the LV on the tagged MRI images into infarct, adjacent, and remote sectors. Motion tracking was performed using the infarct-specific two-parameter empirical deformable model (TPEDM). The match quality was defined as the position error computed using root-mean-square (RMS) distance between the estimated and expert-verified tag intersections. The position errors were compared with the ones from our previously published fixed-sector TPEDM. Cine MRI images were used to calculate regional ejection fraction (REF). Correlation between the end-systolic contraction parameter (αES ) with REF was determined. RESULTS: The position errors in the proposed model were significantly lower than the fixed-sector model (P < 0.01). The median position errors were 0.82 mm versus 1.23 mm. The αES correlates significantly with REF (r = 0.91, P < 0.01). CONCLUSION: The infarct-specific TPEDM combines the morphological and functional information from LGE and tagged MRI images. It was shown to outperform the fixed-sector model in assessing regional LV dysfunction. The significant correlation between αES and REF added prognostic value because it indicated an impairment of cardiac function with the increase of infarct transmurality. LEVEL OF EVIDENCE: 3 J. Magn. Reson. Imaging 2017;45:525-534.

Response of Arterial Stiffness Four Weeks After Terminating Short-term Aerobic Exercise Training in a Sedentary Lifestyle.

OBJECTIVES: The purpose of this study was to investigate the response of arterial stiffness in individuals with a sedentary lifestyle at 4 weeks after terminating a 2-week aerobic exercise session. METHODS: Arterial stiffness was evaluated in 38 participants before starting and after completing a prescribed aerobic exercise program and also at 4 weeks after returning back to their sedentary lifestyle. Parameters regarding arterial compliance, distensibility, wall stress, and the elastic modulus were estimated from the information gained from sonography on the dimensions of carotid and femoral arteries and a sphygmomanometer on the pulse pressure. RESULTS: Primary outcomes included whether short-term aerobic exercise reduced the heart rate, arterial pressure, and intima-media thickness and improved vascular biomechanics in physically inactive but otherwise healthy individuals. The benefits gained in arterial compliance and distensibility deteriorated with termination of exercise, but diastolic wall stress and the elastic modulus improved further. CONCLUSIONS: In individuals with sedentary lifestyles, short-term aerobic exercise has strong four-week residual benefits on diastolic wall stress and the elastic modulus, but the effects appear to be negligible on arterial stiffness and distensibility.

A magnetic resonance imaging study on the articulatory and acoustic speech parameters of Malay vowels.

The phonetic properties of six Malay vowels are investigated using magnetic resonance imaging (MRI) to visualize the vocal tract in order to obtain dynamic articulatory parameters during speech production. To resolve image blurring due to the tongue movement during the scanning process, a method based on active contour extraction is used to track tongue contours. The proposed method efficiently tracks tongue contours despite the partial blurring of MRI images. Consequently, the articulatory parameters that are effectively measured as tongue movement is observed, and the specific shape of the tongue and its position for all six uttered Malay vowels are determined.Speech rehabilitation procedure demands some kind of visual perceivable prototype of speech articulation. To investigate the validity of the measured articulatory parameters based on acoustic theory of speech production, an acoustic analysis based on the uttered vowels by subjects has been performed. As the acoustic speech and articulatory parameters of uttered speech were examined, a correlation between formant frequencies and articulatory parameters was observed. The experiments reported a positive correlation between the constriction location of the tongue body and the first formant frequency, as well as a negative correlation between the constriction location of the tongue tip and the second formant frequency. The results demonstrate that the proposed method is an effective tool for the dynamic study of speech production.

Protective activity of Panduratin A against thioacetamide-induced oxidative damage: demonstration with in vitro experiments using WRL-68 liver cell line.

BACKGROUND: Chalcone Panduratin A (PA) has been known for its antioxidant property, but its merits against oxidative damage in liver cells has yet to be investigated. Hence, the paper aimed at accomplishing this task with normal embryonic cell line WRL-68. METHODS: PA was isolated from Boesenbergia rotunda rhizomes and its 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging and ferric reducing power (FRAP) activities were measured in comparison with that of the standard reference drug Silymarin (SI). Oxidative damage was induced by treating the cells with 0.04 g/ml of toxic thioacetamide for 60 minutes followed by treatment with 1, 10 and 100 µg/ml concentrations of either PA or SI. The severities of oxidative stress in the control and experimental groups of cells were measured by Malondialdehyde (MDA) levels, superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) activities. RESULTS: PA exhibited an acceptable DPPH scavenging and FRAP activities close to that of Silymarin. Treating the injured cells with PA significantly reduced the MDA level and increased the cell viability, comparable to SI. The activities of SOD, CAT and GPx were significantly elevated in the PA-treated cells in a dose dependent manner and again similar to SI. CONCLUSION: Collectively, data suggested that PA has capacity to protect normal liver cells from oxidative damage, most likely via its antioxidant scavenging ability.

Construction of a two-parameter empirical model of left ventricle wall motion using cardiac tagged magnetic resonance imaging data.

BACKGROUND: A one-parameter model was previously proposed to characterize the short axis motion of the LV wall at the mid-ventricle level. The single parameter of this model was associated with the radial contraction of myocardium, but more comprehensive model was needed to account for the rotation at the apex and base levels. The current study developed such model and demonstrated its merits and limitations with examples. MATERIALS AND METHODS: The hearts of five healthy individuals were visualized using cardiac tagged magnetic resonance imaging (tMRI) covering the contraction and relaxation phases. Based on the characteristics of the overall dynamics of the LV wall, its motion was represented by a combination of two components - radial and rotational. Each component was represented by a transformation matrix with a time-dependent variable α or ß.Image preprocessing step and model fitting algorithm were described and applied to estimate the temporal profiles of α and ß within a cardiac cycle at the apex, mid-ventricle and base levels. During this process, the tagged lines of the acquired images served as landmark reference for comparing against the model prediction of the motion. Qualitative and quantitative analyses were performed for testing the performance of the model and thus its validation. RESULTS: The α and ß estimates exhibited similarities in values and temporal trends once they were scaled by the radius of the epicardium (r(epi))and plotted against the time scaled by the period of the cardiac cycle (T(cardiac)) of each heart measured during the data acquisition. α/repi peaked at about Δt/T(cardiac)=0.4 and with values 0.34, 0.4 and 0.3 for the apex, mid-ventricle and base level, respectively. ß/r(epi) similarly maximized in amplitude at about Δt/T(cardiac)=0.4, but read 0.2 for the apex and - 0.08 for the base level. The difference indicated that the apex twisted more than the base. CONCLUSION: It is feasible to empirically model the spatial and temporal evolution of the LV wall motion using a two-parameter formulation in conjunction with tMRI-based visualization of the LV wall in the transverse planes of the apex, mid-ventricle and base. In healthy hearts, the analytical model will potentially allow deriving biomechanical entities, such as strain, strain rate or torsion, which are typically used as diagnostic, prognostic or predictive markers of cardiovascular diseases including diabetes.

Prospects of implant with locking plate in fixation of subtrochanteric fracture: experimental demonstration of its potential benefits on synthetic femur model with supportive hierarchical nonlinear hyperelastic finite element analysis.

BACKGROUND: Effective fixation of fracture requires careful selection of a suitable implant to provide stability and durability. Implant with a feature of locking plate (LP) has been used widely for treating distal fractures in femur because of its favourable clinical outcome, but its potential in fixing proximal fractures in the subtrochancteric region has yet to be explored. Therefore, this comparative study was undertaken to demonstrate the merits of the LP implant in treating the subtrochancteric fracture by comparing its performance limits against those obtained with the more traditional implants; angle blade plate (ABP) and dynamic condylar screw plate (DCSP). MATERIALS AND METHODS: Nine standard composite femurs were acquired, divided into three groups and fixed with LP (n = 3), ABP (n = 3) and DCSP (n = 3). The fracture was modeled by a 20 mm gap created at the subtrochanteric region to experimentally study the biomechanical response of each implant under both static and dynamic axial loading paradigms. To confirm the experimental findings and to understand the critical interactions at the boundaries, the synthetic femur/implant systems were numerically analyzed by constructing hierarchical finite element models with nonlinear hyperelastic properties. The predictions from the analyses were then compared against the experimental measurements to demonstrate the validity of each numeric model, and to characterize the internal load distribution in the femur and load bearing properties of each implant. RESULTS: The average measurements indicated that the constructs with ABP, DCPS and LP respectively had overall stiffness values of 70.9, 110.2 and 131.4 N/mm, and exhibited reversible deformations of 12.4, 4.9 and 4.1 mm when the applied dynamic load was 400 N and plastic deformations of 11.3, 2.4 and 1.4 mm when the load was 1000 N. The corresponding peak cyclic loads to failure were 1100, 1167 and 1600 N. The errors between the displacements measured experimentally or predicted by the nonlinear hierarchical hyperelastic model were less than 18 %. In the implanted femur heads, the principal stresses were spatially heterogeneous for ABP and DCSP but more homogenous for LP, meaning LP had lower stress concentrations. CONCLUSION: When fixed with the LP implant, the synthetic femur model of the subtrochancteric fracture consistently exceeds in the key biomechanical measures of stability and durability. These capabilities suggest increased resistance to fatigue and failure, which are highly desirable features expected of functional implants and hence make the LP implant potentially a viable alternative to the conventional ABP or DCSP in the treatment of subtrochancteric femur fractures for the betterment of clinical outcome.

Efficacy of Boesenbergia rotunda Treatment against Thioacetamide-Induced Liver Cirrhosis in a Rat Model.

Background. Experimental research in hepatology has focused on developing traditional medicines into potential pharmacological solutions aimed at protecting liver from cirrhosis. Along the same line, this study investigated the effects of ethanol-based extract from a traditional medicine plant Boesenbergia rotunda (BR) on liver cirrhosis. Methodology/Results. The BR extract was tested for toxicity on 3 groups of rats subjected to vehicle (10% Tween 20, 5 mL/kg) and 2g/kg and 5g/kg doses of the extract, respectively. Next, experiments were conducted on a rat model of cirrhosis induced by thioacetamide injection. The rats were divided into five groups and, respectively, administered orally with 10% Tween-20 (5 mL/kg) (normal control group), 10% Tween-20 (5 mL/kg) (cirrhosis control group), 50 mg/kg of silymarin (reference control group), and 250 mg/kg and 500 mg/kg of BR extract (experimental groups) daily for 8 weeks. The rats in normal group were intraperitoneally injected with sterile distilled water (1 mL/kg) 3 times/week, and those in the remaining groups were injected intraperitoneally with thioacetamide (200 mg/kg) thrice weekly. At the end of the 8 weeks, the animals were sacrificed and samples were collected for comprehensive histopathological, coagulation profile and biochemical evaluations. Also, the antioxidant activity of the BR extract was determined and compared with that of silymarin. Data from the acute toxicity tests showed that the extract was safe to use. Histological analysis of the livers of the rats in cirrhosis control group revealed uniform coarse granules on their surfaces, hepatocytic necrosis, and lymphocytes infiltration. But, the surfaces morphologically looked much smoother and the cell damage was much lesser in those livers from the normal control, silymarin and BR-treated groups. In the high-dose BR treatment group, the livers of the rats exhibited nearly normal looking lobular architecture, minimal inflammation, and minimal hepatocyte damage, the levels of the serum biomarkers and liver enzymes read nearly normal, and these results were all comparable to those observed or quantified from the normal and silymarin-treated groups. The BR extract had the antioxidant activity about half of what was recorded for silymarin. Conclusion. The progression of the liver cirrhosis can be intervened using the ethanol-based BR extract, and the liver's status quo of property, structure, and function can be preserved. This capability of the extract warrants further studies exploring the significance of its pharmacologic potential in successfully treating the liver cirrhosis in humans.

Protective Role of Phyllanthus niruri Extract against Thioacetamide-Induced Liver Cirrhosis in Rat Model.

A preclinical study was performed to determine if the extract from Phyllanthus niruri (PN) plays a protective role against liver cirrhosis induced by thioacetamide (TAA) in rats. Initially, acute toxicity was tested and the results showed that the extract was benign when applied to healthy rats. Next, the therapeutic effect of the extract was investigated using five groups of rats: control, TAA, silymarin, and PN high dose and low dose groups. Significant differences were observed between the TAA group and the other groups regarding body and liver weights, liver biochemical parameters, total antioxidant capacity, lipid peroxidation, and oxidative stress enzyme levels. Gross visualization indicated coarse granules on the surface of the hepatotoxic rats' livers, in contrast to the smoother surface in the livers of the silymarin and PN-treated rats. Histopathological analysis revealed necrosis, lymphocytes infiltration in the centrilobular region, and fibrous connective tissue proliferation in the livers of the hepatotoxic rats. But, the livers of the treated rats had comparatively minimal inflammation and normal lobular architecture. Silymarin and PN treatments effectively restored these measurements closer to their normal levels. Progression of liver cirrhosis induced by TAA in rats can be intervened using the PN extract and these effects are comparable to those of silymarin.

Loss of primary cilia upregulates renal hypertrophic signaling and promotes cystogenesis.

Primary cilia dysfunction alters renal tubular cell proliferation and differentiation and associates with accelerated cyst formation in polycystic kidney disease. However, the mechanism leading from primary ciliary dysfunction to renal cyst formation is unknown. We hypothesize that primary cilia prevent renal cyst formation by suppressing pathologic tubular cell hypertrophy and proliferation. Unilateral nephrectomy initiates tubular cell hypertrophy and proliferation in the contralateral kidney and provides a tool to examine primary cilia regulation of renal hypertrophy. Conditional knockout of the primary cilia ift88 gene leads to delayed, adult-onset renal cystic disease, which provides a window of opportunity to conduct unilateral nephrectomy and examine downstream kinetics of renal hypertrophy and cyst formation. In wild-type animals, unilateral nephrectomy activated the mTOR pathway and produced appropriate structural and functional hypertrophy without renal cyst formation. However, in ift88 conditional knockout animals, unilateral nephrectomy triggered increased renal hypertrophy and accelerated renal cyst formation, leading to renal dysfunction. mTOR signaling also increased compared with wild-type animals, suggesting a mechanistic cascade starting with primary ciliary dysfunction, leading to excessive mTOR signaling and renal hypertrophic signaling and culminating in cyst formation. These data suggest that events initiating hypertrophic signaling, such as structural or functional loss of renal mass, may accelerate progression of adult polycystic kidney disease toward end-stage renal disease.

Preclinical use of longitudinal MRI for screening the efficacy of S-nitrosoglutathione in treating spinal cord injury.

PURPOSE: To evaluate the therapeutic efficacy of S-nitrosoglutathione (GSNO) in spinal cord injury (SCI) using in vivo MRI in combination with neuorobehavioral testing and postmortem tissue analysis. MATERIALS AND METHODS: Sixteen female rats were mildly injured at the vertebral T10 level and randomized into control (n = 8) and GSNO-treatment (n = 8) groups. GSNO was delivered at 0.05 mg/kg dose in saline by means of tail vein at 1 hr postinjury and then given orally on the following days. On postinjury days 1, 3, 7, and 28, the rats were tested behaviorally, then scanned using sagittal T2-weighted MRI for the quantification of lesion, edema, and hemorrhagic regions at the injury site. Excised cords were analyzed using histology and immunohistochemistry. RESULTS: Treatment with GSNO was feasible in rats with SCI. On the average, the GSNO group at each scan day 1, 3, 7, and 28 exhibited better functional recovery as indicated by the behavioral performance of 52%, 33%, 19%, and 18%, and had smaller lesions of -4%, -16%, -20%, and -17% compared with the controls, respectively. Edema trend was parallel to the lesion volumes in both groups. Ex vivo data demonstrated that GSNO plays a role in neuronal tissue preservation and sparing. CONCLUSION: The data collectively provided the preliminary evidence that the injured rats responded favorably to GSNO treatment. Longitudinal MRI provides critical quantitative information regarding the changes in lesion properties, which helps evaluating the efficacy of an exogenous intervention in SCI.

MRI-based modeling for radiocarpal joint mechanics: validation criteria and results for four specimen-specific models.

The objective of this study was to validate the MRI-based joint contact modeling methodology in the radiocarpal joints by comparison of model results with invasive specimen-specific radiocarpal contact measurements from four cadaver experiments. We used a single validation criterion for multiple outcome measures to characterize the utility and overall validity of the modeling approach. For each experiment, a Pressurex film and a Tekscan sensor were sequentially placed into the radiocarpal joints during simulated grasp. Computer models were constructed based on MRI visualization of the cadaver specimens without load. Images were also acquired during the loaded configuration used with the direct experimental measurements. Geometric surface models of the radius, scaphoid and lunate (including cartilage) were constructed from the images acquired without the load. The carpal bone motions from the unloaded state to the loaded state were determined using a series of 3D image registrations. Cartilage thickness was assumed uniform at 1.0 mm with an effective compressive modulus of 4 MPa. Validation was based on experimental versus model contact area, contact force, average contact pressure and peak contact pressure for the radioscaphoid and radiolunate articulations. Contact area was also measured directly from images acquired under load and compared to the experimental and model data. Qualitatively, there was good correspondence between the MRI-based model data and experimental data, with consistent relative size, shape and location of radioscaphoid and radiolunate contact regions. Quantitative data from the model generally compared well with the experimental data for all specimens. Contact area from the MRI-based model was very similar to the contact area measured directly from the images. For all outcome measures except average and peak pressures, at least two specimen models met the validation criteria with respect to experimental measurements for both articulations. Only the model for one specimen met the validation criteria for average and peak pressure of both articulations; however the experimental measures for peak pressure also exhibited high variability. MRI-based modeling can reliably be used for evaluating the contact area and contact force with similar confidence as in currently available experimental techniques. Average contact pressure, and peak contact pressure were more variable from all measurement techniques, and these measures from MRI-based modeling should be used with some caution.

Quantitative ultrasound measurement of the calcaneus in Southeast Asian children with thalassemia: comparison with dual-energy X-ray absorptiometry.

OBJECTIVES: The purpose of this study was to test the hypothesis that quantitative ultrasound properties of the calcaneus in Southeast Asian children treated for thalassemia have different characteristics than those of their healthy counterparts and thereby can be used for assessing the risk of osteoporosis. METHODS: Broadband ultrasound attenuation and the speed of sound were measured from groups of thalassemic and healthy children and compared with bone mineral density (BMD) estimated from dual-energy X-ray absorptiometry to determine intergroup and intragroup dependencies of the measurements and variations with differences in sex and anthropometric characteristics. RESULTS: Broadband ultrasound attenuation and speed of sound measurements were found to be independent of sex but dependent on age in the thalassemic children. Consistently, broadband ultrasound attenuation had lower values and the speed of sound had higher values compared with those of the healthy children in each age group. Broadband ultrasound attenuation correlated well with the speed of sound and also with age, weight, and height, but the speed of sound did not show an association with these parameters. Broadband ultrasound attenuation correlated moderately with BMD in the lumbar spine and whole body, but the corresponding association was much weaker for the speed of sound. In the thalassemic children, both broadband ultrasound attenuation and BMD increased with age as they grew older but not fast enough compared with the healthy children, and the risk of osteoporosis was greater at older ages. CONCLUSIONS: Calcaneal quantitative ultrasound may be used as a diagnostic screening tool for assessing the bone status in thalassemic Southeast Asian children and for deciding whether further dual-energy X-ray absorptiometry is needed, particularly in those who are at a greater risk for osteoporosis as identified by low body weight and height.

Harmonic phase interference for the detection of tag line crossings and beyond in homogeneous strain analysis of cardiac tagged MRI data.

Homogenous strain analysis (HSA) was developed to evaluate regional cardiac function using tagged cine magnetic resonance images of heart. Current cardiac applications of HSA are however limited in accurately detecting tag intersections within the myocardial wall, producing consistent triangulation of tag cells throughout the image series and achieving optimal spatial resolution due to the large size of the triangles. To address these issues, this article introduces a harmonic phase (HARP) interference method. In principle, as in the standard HARP analysis, the method uses harmonic phases associated with the two of the four fundamental peaks in the spectrum of a tagged image. However, the phase associated with each peak is wrapped when estimated digitally. This article shows that special combination of wrapped phases results in an image with unique intensity pattern that can be exploited to automatically detect tag intersections and to produce reliable triangulation with regularly organized partitioning of the mesh for HSA. In addition, the method offers new opportunities and freedom for evaluating myocardial function when the power and angle of the complex filtered spectra are mathematically modified prior to computing the phase. For example, the triangular elements can be shifted spatially by changing the angle and/or their sizes can be reduced by changing the power. Interference patterns obtained under a variety of power and angle conditions were presented and specific features observed in the results were explained. Together, the advanced processing capabilities increase the power of HSA by making the analysis less prone to errors from human interactions. It also allows strain measurements at higher spatial resolution and multi-scale, thereby improving the display methods for better interpretation of the analysis results.

Sonoelastic response of median nerve to rehabilitation in carpal tunnel syndrome.

Aim of the study: To evaluate the sonoelastic response of the median nerve in patients with carpal tunnel syndrome following conservative rehabilitation with splint plus exercise regimens. Materials and methods: A total of thirty-five patients diagnosed with mild carpal tunnel syndrome and treated with splint plus exercise therapy; hand resting splint all day for 3 weeks and then only at nights along with nerve gliding exercises in 10 repetitions 3 times a day. The median nerve was evaluated clinically prior to the treatment and at week 6 of therapy using physical examination, electrodiagnostic neurophysiology tests and radiological imaging; Boston Scores, electromyogram, ultrasonography and sonoelastography. Results: Following the 6-week treatment protocol on 35 subjects with mild carpal tunnel syndrome, sonoelastography showed significantly softer median nerve, while the traditional parameters based on Boston Scores and cross-sectional area based on ultrasonography remained nearly unresponsive. Such early indication of biomechanical changes in the nerve may be of clinical importance if it can offer a prognostic value of the applied treatment, while tissue softening suggests the alleviation of nerve compression. Conclusions: Sonoelasticity of the median nerve can serve as a reliable marker for assessing therapeutic changes in median nerve stiffness and potentially the outcome early on in mild carpal tunnel syndrome.Aim of the study: To evaluate the sonoelastic response of the median nerve in patients with carpal tunnel syndrome following conservative rehabilitation with splint plus exercise regimens. Materials and methods: A total of thirty-five patients diagnosed with mild carpal tunnel syndrome and treated with splint plus exercise therapy; hand resting splint all day for 3 weeks and then only at nights along with nerve gliding exercises in 10 repetitions 3 times a day. The median nerve was evaluated clinically prior to the treatment and at week 6 of therapy using physical examination, electrodiagnostic neurophysiology tests and radiological imaging; Boston Scores, electromyogram, ultrasonography and sonoelastography. Results: Following the 6-week treatment protocol on 35 subjects with mild carpal tunnel syndrome, sonoelastography showed significantly softer median nerve, while the traditional parameters based on Boston Scores and cross-sectional area based on ultrasonography remained nearly unresponsive. Such early indication of biomechanical changes in the nerve may be of clinical importance if it can offer a prognostic value of the applied treatment, while tissue softening suggests the alleviation of nerve compression. Conclusions: Sonoelasticity of the median nerve can serve as a reliable marker for assessing therapeutic changes in median nerve stiffness and potentially the outcome early on in mild carpal tunnel syndrome.

Assessing gait impairment following experimental traumatic brain injury in mice.

Although gait disturbance is frequently documented among patients with traumatic brain injury (TBI), gait data from animal models of TBI are lacking. To determine the effect of TBI on gait function in adult mice, we assessed gait changes following unilateral controlled cortical impact (CCI) using a computer-assisted automated gait analysis system. Three days after CCI, intensity, area or width of paw contact were significantly decreased in forepaw(s) while the relative paw placement between the fore and hindpaws altered, suggesting that TBI affected sensorimotor status and reduced interlimb coordination. Similar to TBI patients, CCI decreased gait velocity and stride length, and prolonged stance and swing phase in mice. Following CCI, step pattern was also changed with increasing use in the ipsilateral-diagonal limb sequence. Our results indicate that gait analysis provides great insight into both spatial and temporal aspects of limb function changes during overground locomotion in quadruped species with head injury that are valuable for the purpose of treatment and rehabilitation. Our study also provides additional functional validation for the established mouse CCI model that is relevant to human head injury.

Evaluating regional blood spinal cord barrier dysfunction following spinal cord injury using longitudinal dynamic contrast-enhanced MRI.

BACKGROUND: In vivo preclinical imaging of spinal cord injury (SCI) in rodent models provides clinically relevant information in translational research. This paper uses multimodal magnetic resonance imaging (MRI) to investigate neurovascular pathology and changes in blood spinal cord barrier (BSCB) permeability following SCI in a mouse model of SCI. METHODS: C57BL/6 female mice (n = 5) were subjected to contusive injury at the thoracic T11 level and scanned on post injury days 1 and 3 using anatomical, dynamic contrast-enhanced (DCE-MRI) and diffusion tensor imaging (DTI). The injured cords were evaluated postmortem with histopathological stains specific to neurovascular changes. A computational model was implemented to map local changes in barrier function from the contrast enhancement. The area and volume of spinal cord tissue with dysfunctional barrier were determined using semi-automatic segmentation. RESULTS: Quantitative maps derived from the acquired DCE-MRI data depicted the degree of BSCB permeability variations in injured spinal cords. At the injury sites, the damaged barriers occupied about 70% of the total cross section and 48% of the total volume on day 1, but the corresponding measurements were reduced to 55% and 25%, respectively on day 3. These changes implied spatio-temporal remodeling of microvasculature and its architecture in injured SC. Diffusion computations included longitudinal and transverse diffusivities and fractional anisotropy index. Comparison of permeability and diffusion measurements indicated regions of injured cords with dysfunctional barriers had structural changes in the form of greater axonal loss and demyelination, as supported by histopathologic assessments. CONCLUSION: The results from this study collectively demonstrated the feasibility of quantitatively mapping regional BSCB dysfunction in injured cord in mouse and obtaining complementary information about its structural integrity using in vivo DCE-MRI and DTI protocols. This capability is expected to play an important role in characterizing the neurovascular changes and reorganization following SCI in longitudinal preclinical experiments, but with potential clinical implications.

Effects of gadolinium and gadolinium chelates on intracellular calcium signaling in sensory neurons.

Magnetic resonance imaging (MRI) employs gadolinium chelates as contrast agents to provide signal enhancement in radiological images. However, the instability of the chelates presents a challenge as the released gadolinium ion (Gd3+) from the chelates becomes toxic to the surrounding biological tissue. Chelates such as gadodiamide, gadoterate meglumine, gadobutrol and gadobenate dimeglumine are common contrast agents used in clinics. The release of Gd3+ from these agents have been reported previously using experimental setups involving water, but this study evaluates the release in cell culture of dorsal root ganglion (DRG) neurons as this model system is relevant to neuronal toxicity induced by these agents. DRG neurons were grown in primary culture following enzymatic and mechanical dissociation of ganglia from a 2-day-old neonatal Wistar rat. Using Fura-2 based calcium imaging, the effects of gadolinium chelates on free intracellular Ca2+ transport was assessed. The findings indicated that the contrast agent gadoterate meglumine exhibited the best performance in complex stability, independent of its concentration, and thus it must be taken into consideration in standard MRI exams and neuroimaging. The free Gd3+ released from the other agents is also of great concern as it may impact the neurophysiology of the neuronal cells in general, even in normal patients without nephrogenic systemic fibrosis.