A power efficient actively shielded two-channel transverse MRI gradient coil numerical design.

Large and fast electrical current pulses are typically applied to conventional single-channel transverse MR gradient coils. However, these pulses result in a significant amount of power losses and heating of the coils. Previously, we presented a cylindrical multi-channel Z-gradient coil design that has better power efficiency compared to the single-channel design. In this work, we further investigate the DC power advantage for a two-channel actively-shielded transverse cylindrical gradient coil over the single-channel design. The conventional coil quadrants are radially divided into two sections, one for each channel, for both the primary and shielding surfaces. The symmetric inner sections of both the primary and shielding coils are assigned to the first channel, while the outer enclosing sections for each quadrant are assigned to the second channel. Discrete wire design is employed, where quasi-elliptic functions are used to parameterize the turns of each section. The coil geometric parameters, section size, number of turns, and turn locations are used as the design optimization parameters. The coils are optimized to maximize the coil's efficiency while keeping the linearity error less than 10% and the shielding ratio above 85%. The design procedure is employed to design both the single and two-channel transverse gradient coils for comparison. Eleven different two-channel configurations having different section sizes were investigated. Results show that the power used to drive the most power-efficient two-channel coil is less than that of the single-channel design by ∼25%. Moreover, the two-channel configuration showed slightly better shielding efficiency.

Eddy currents analysis methods for an MRI longitudinal gradient coil.

PURPOSE: The rapid switching of the gradient fields induces eddy currents in neighboring metallic structures, causing undesirable effects. Numerical computations are thus required to understand eddy-currents effects for designing/implementing mitigation (involving passive shielding) and compensating techniques (using pre-emphasis). Previously, the network-analysis (NA) method was introduced to compute z-gradient eddy currents, although limited to a circularly symmetric and unconnected coil. Multi-layer integral method (MIM) method was recently introduced, modifying the circuit equation involving stream functions. We tailor MIM (TMIM) for a more general eddy-currents analysis in thin structures. Z-gradient eddy currents are analyzed and then compared using three methods (NA, TMIM, and Ansys). The analysis helps to evaluate the efficiency of passive shielding and to compensate eddy currents. METHODS: NA and TMIM computational frameworks for harmonic and transient eddy-currents analysis were implemented and cross-validated against Ansys Maxwell. A pre-emphasis pulse was modeled for compensating eddy currents. RESULTS: Eddy-currents analysis of an unconnected z-gradient coil in both the passive shield and cryostat were computed, and results were comparable to the least computationally efficient Ansys simulations. Although NA computations are fast, TMIM is implemented with reasonable efficiency and applied to circularly unsymmetric geometries. TMIM computations were further validated against Ansys using a connected z-gradient. Our computations allowed the effective evaluation of the performance of three various passive-shielding configurations, non-capped, capped, and slitted (for the first time), and an effective pre-emphasis compensation model was computed. CONCLUSION: Three eddy-currents analysis methods were studied and compared. Computationally efficient TMIM allows both harmonic and transient eddy-currents analysis involving different/complex gradient configurations/situations as well as involved shielding structures. Eddy-currents pre-emphasis compensation was demonstrated.

Transient eddy current analysis for a spiral gradient pulse.

Eddy currents are induced in the metallic structures of MRI machines due to the rapid switching of gradient fields generated by gradient coils. Several undesirable effects are associated with the induced eddy currents such as heat, acoustic noise, and MR image distortions. Accurate transient eddy currents numerical computations are required to predict and ameliorate such effects. Spiral gradient waveforms are of importance, particularly for fast MRI acquisition applications. For mathematical convenience, previously published work is mostly concerned with transient eddy currents computations associated with trapezoidal gradient waveforms; where spiral gradient waveforms were not considered. We recently presented preliminary transient eddy currents computations induced by an amplitude-modulated sinusoidal pulse in the scanner's cryostat. In this work, we present a full computational framework for transient eddy currents induced by a spiral gradient waveform. A mathematical model for transient eddy currents involving the spiral pulse was derived and presented in detail using the circuit equation. Computations were implemented using a tailored multilayer integral method (TMIM) and results were compared to Ansys eddy currents analysis for cross-validation. The transient response of resultant fields generated by both an unshielded transverse coil driven by a spiral waveform was computed showing high agreement between Ansys and TMIM; albeit with high computational efficiency concerning time and memory. For further validation, computations for a shielded transverse coil were performed showing how eddy currents effects are reduced.

Study of Different Local Treatments of Post COVID-19 Smell Dysfunction.

Introduction: This study was designed to differentiate between the impact of the topical nasal spray of corticosteroids, antihistamines, a combination of them, and normal 0.2% saline in treating patients with post-coronavirus disease 2019 (COVID-19) smell dysfunction. Materials and Methods: Patients with hyposmia or anosmia (n = 240), who recently recovered from COVID-19, were enrolled in this trial and were randomly assigned to four parallel groups. Group I (G1) received a combination of topical corticosteroid and antihistamine nasal spray (n = 60). Group II (G2) received topical corticosteroid nasal spray (n = 60). Group III (G3) received antihistamine nasal spray (n = 60). Group IV (G4) received 0.2% normal nasal saline nasal spray (n = 60). The treatments were used in all groups for 3 weeks. The sense of smell was assessed using the butanol threshold and discrimination tests. The smell tests were evaluated weekly for 3 weeks. Results: The mean age of the patients was 51.9 ± 7.1 years; moreover, 83.8% and 16.2% were male and female, respectively. The results of the smell tests in the first week significantly improved with those in the third week (P< 0.001). The greatest degree of improvement was found in the first group, followed by the second, third, and fourth groups. Conclusions: The results suggest the ability of combination therapy of corticosteroid and antihistamine nasal spray to manage post-COVID-19 hyposmia or anosmia; however, this combination therapy was not superior to corticosteroid nasal spray. Trial registration ID: UMIN000043537.

Anti-otomycotic potential of nanoparticles of Moringa oleifera leaf extract: an integrated in vitro, in silico and phase 0 clinical study.

Otomycosis is a serious superficial mycotic infection of the outer ear canal caused by some pathogenic species of Candida and Aspergillus. The infection remains a challenge to clinicians owing to the incomplete efficacy of market-available antifungal agents and high recurrence rates. The Moringa oleifera leaf ethanol extract showed efficacy against Candida albicans SC5314, compared to Nystatin® as a reference with MIC values of 7 and 718.33 µg ml-1, respectively. The extract was mixed with lecithin and chitosan to give Moringa core/shell giant nanoparticles, with a good zeta potential (+59.2 mV), a suitable entrapment efficiency (61%) and an enhanced release reaching up to 90% at 8 h. Clinical isolates from oomycote patients were identified via DNA sequencing as Candida parapsilosis, Aspergillus niger and Aspergillus flavus, and the effect of the prepared nanoparticles was tested against them via disk diffusion assay to give inhibition zones of 75, 55 and 55 mm, compared to Nystatin® with 35, 25 and 20 mm, respectively. Interestingly, patients treated with the Moringa-loaded nanoparticles experienced improvement within 1 week with no recurrence for more than 3 months. To have some insight into the bioactive components in the Moringa extract, LC-HRMS-based identification has been employed which led to the annotation of 27 compounds. Subsequent comprehensive in silico investigation suggested some alkaloids to be responsible for the activity targeting the fungal 14-α-demethylase enzyme (CYP51B). Our study revealed that Moringa extract-loaded nanoparticles attained an enhanced antifungal efficacy compared to Nystatin® and therefore they can be employed against invasive and drug-resistant otomycotic infections.

The Potential of Corchorus olitorius Seeds Buccal Films for Treatment of Recurrent Minor Aphthous Ulcerations in Human Volunteers.

Aphthous ulcers are very common disorders among different age groups and are very noxious and painful. The incidence of aphthous ulcer recurrence is very high and it may even last for a maximum of 6 days and usually, patients cannot stand its pain. This study aims to prepare a buccoadhesive fast dissolving film containing Corchorus olitorius seed extract to treat recurrent minor aphthous ulceration (RMAU) in addition to clinical experiments on human volunteers. An excision wound model was used to assess the in vivo wound healing potential of Corchorus olitorius L. seed extract, with a focus on wound healing molecular targets such as TGF-, TNF-, and IL-1. In addition, metabolomic profiling using HR-LCMS for the crude extract of Corchorus olitorius seeds was explored. Moreover, molecular docking experiments were performed to elucidate the binding confirmation of the isolated compounds with three molecular targets (TNF-α, IL-1ß, and GSK3). Additionally, the in vitro antioxidant potential of C. olitorius seed extract using both H2O2 and superoxide radical scavenging activity was examined. Clinical experiments on human volunteers revealed the efficiency of the prepared C. olitorius seeds buccal fast dissolving film (CoBFDF) in relieving pain and wound healing of RMAU. Moreover, the wound healing results revealed that C. olitorius seed extract enhanced wound closure rates (p ≤ 0.001), elevated TGF-ß levels and significantly downregulated TNF-α and IL-1ß in comparison to the Mebo-treated group. The phenotypical results were supported by biochemical and histopathological findings, while metabolomic profiling using HR-LCMS for the crude extract of Corchorus olitorius seeds yielded a total of 21 compounds belonging to diverse chemical classes. Finally, this study highlights the potential of C. olitorius seed extract in wound repair uncovering the most probable mechanisms of action using in silico analysis.

A Comparative Study for Evaluating Passive Shielding of MRI Longitudinal Gradient Coil.

Gradient coils are vital for Magnetic Resonance Imaging (MRI). Their rapid switching generates eddy currents in the surrounding metallic structures of the MRI scanner causing undesirable thermal, acoustic, and field distortion effects. The use of actively shielded gradient coils does not eliminate such undesirable effects totally. Use of passive shielding was proposed lately to particularly help in mitigating eddy currents and loud acoustic noise. Numerical computations are necessary for calculating eddy currents and evaluating the efficacy of passive shielding. Harmonic and temporal eddy current analysis caused by gradient coil(s) using network analysis (NA) can be faster and more flexible than the traditional FDTD and FEM methods. NA was used more than a decade ago but was limited to analyzing eddy currents resulting from z-gradient coils of separated turns. NA with stream function was recently modified resulting in the more general Multilayer Integral Method (MIM) for simulation of eddy currents in thin structures of arbitrary geometries. In this work, we compared the performance of the NA method and an adapted MIM method to analyze eddy current in both the passive shielding and cryostat to the Ansys Maxwell 3D analysis thus evaluating the performance of gradient configurations with and without passive shielding. Both an unconnected and a connected z-gradient coil configuration were used. Our analysis showed high agreement in the profiles of eddy ohmic losses in metallic structures using the three methods. The NA method is the most computationally efficient however, it is limited to specific symmetries unlike the more general MIM and Ansys methods. Our implementation of the adapted MIM method showed computational efficiency relative to Ansys with comparable values. We have developed a computationally efficient eddy current analysis framework that can be used to evaluate more designs for passive shielding using different configurations of MRI gradient coils.

Insulin fast-dissolving film for intranasal delivery via olfactory region, a promising approach for the treatment of anosmia in COVID-19 patients: Design, in-vitro characterization and clinical evaluation.

The present work aimed to formulate intranasal insulin fast-dissolving films for treatment of anosmia in patients post COVID-19 infection. Variant films were prepared employing the casting method and using hydroxypropyl methyl cellulose and polyvinyl alcohol. The formulated films were investigated for insulin content, weight variation, surface pH, thickness, folding endurance and disintegration time. In vitro release study was conducted for the selected formulations (F6, F7, F8). A drug/polymer interaction was investigated in the optimized formulation (F7) employing Fourier transform infrared spectroscopy. Clinical study was accomplished for F7 on 20 patients. Sniffin's and olfactory discrimination tests were used for assessing patients. The formulated films displayed appropriate physical characteristics. F7 showed the shortest disintegration time (50 ± 7 s) and fastest release. It displayed compatibility between the drug and the used polymers. The results of the clinical study revealed a significant increase in the olfactory detection scores and olfactory discrimination values in the intervention group (7.9 ± 1.2, 6.7 ± 0.5 respectively) compared to placebo group (3 ± 0.8, 2.8 ± 1).. Intervention group showed significant differences between these scores before and after treatment while the placebo group did not display any significant differences. Thus, the optimized film can be considered as an auspicious approach for managing post COVID-19 anosmia.

A novel nasal co-loaded loratadine and sulpiride nanoemulsion with improved downregulation of TNF-α, TGF-ß and IL-1 in rabbit models of ovalbumin-induced allergic rhinitis.

PURPOSE: The work aimed to develop a co-loaded loratadine and sulpiride nasal nanoemulsion for allergic rhinitis management. METHODS: Compatibility studies were conducted adopting differential scanning calorimetry and Fourier transform infrared spectroscopy. Nanoemulsion formulations were prepared using soybean lecithin, olive oil and tween 80. Sodium cholate and glycerol were employed as co-surfactants. Nanoemulsions were assessed for viscosity, pH, droplet size, polydispersity index, zeta potential, electrical conductivity, entrapment, In vitro drug release and corresponding kinetics. Stability of the selected formulation was investigated. The biological effectiveness was evaluated in rabbit models of ovalbumin-induced allergic rhinitis by measuring TNF-α, TGF-ß and IL-1. RESULTS: Compatibility studies revealed absence of drug/drug interactions. Nanoemulsions exhibited > 90% entrapment efficiency. The selected nanoemulsion demonstrated small droplet size (85.2 ± 0.2 nm), low PDI (0.35 ± 0.0) and appropriate Zeta Potential (-23.3 ± 0.2) and stability. It also displayed enhanced in vitro drug release following the Higuashi Diffusion and Baker-Lonsdale models. The mean relative mRNA expression of TNF-α, IL-1 and TGF-ß significantly decreased from 9.59 ± 1.06, 4.15 ± 0.02 and 4.15 ± 0.02 to 1.28 ± 0.02, 1.93 ± 0.06 and 1.56 ± 0.02 respectively after treatment with the selected nanoemulsion formulation. CONCLUSION: The results reflected a promising potent effect of the combined loratadine and sulpiride nasal nanoemulsion in managing the symptoms of allergic rhinitis.

Classifying geometric variability by dominant eigenmodes of deformation in regressing tumours during active breath-hold lung cancer radiotherapy.

The purpose of this study is to develop and evaluate a lung tumour interfraction geometric variability classification scheme as a means to guide adaptive radiotherapy and improve measurement of treatment response. Principal component analysis (PCA) was used to generate statistical shape models of the gross tumour volume (GTV) for 12 patients with weekly breath hold CT scans. Each eigenmode of the PCA model was classified as 'trending' or 'non-trending' depending on whether its contribution to the overall GTV variability included a time trend over the treatment course. Trending eigenmodes were used to reconstruct the original semi-automatically delineated GTVs into a reduced model containing only time trends. Reduced models were compared to the original GTVs by analyzing the reconstruction error in the GTV and position. Both retrospective (all weekly images) and prospective (only the first four weekly images) were evaluated. The average volume difference from the original GTV was 4.3% ± 2.4% for the trending model. The positional variability of the GTV over the treatment course, as measured by the standard deviation of the GTV centroid, was 1.9 ± 1.4 mm for the original GTVs, which was reduced to 1.2 ± 0.6 mm for the trending-only model. In 3/13 cases, the dominant eigenmode changed class between the prospective and retrospective models. The trending-only model preserved GTV and shape relative to the original GTVs, while reducing spurious positional variability. The classification scheme appears feasible for separating types of geometric variability by time trend.

Optimizing principal component models for representing interfraction variation in lung cancer radiotherapy.

PURPOSE: To optimize modeling of interfractional anatomical variation during active breath-hold radiotherapy in lung cancer using principal component analysis (PCA). METHODS: In 12 patients analyzed, weekly CT sessions consisting of three repeat intrafraction scans were acquired with active breathing control at the end of normal inspiration. The gross tumor volume (GTV) and lungs were delineated and reviewed on the first week image by physicians and propagated to all other images using deformable image registration. PCA was used to model the target and lung variability during treatment. Four PCA models were generated for each specific patient: (1) Individual models for the GTV and each lung from one image per week (week to week, W2W); (2) a W2W composite model of all structures; (3) individual models using all images (weekly plus repeat intrafraction images, allscans); and (4) composite model with all images. Models were reconstructed retrospectively (using all available images acquired) and prospectively (using only data acquired up to a time point during treatment). Dominant modes representing at least 95% of the total variability were used to reconstruct the observed anatomy. Residual reconstruction error between the model-reconstructed and observed anatomy was calculated to compare the accuracy of the models. RESULTS: An average of 3.4 and 4.9 modes was required for the allscans models, for the GTV and composite models, respectively. The W2W model required one less mode in 40% of the patients. For the retrospective composite W2W model, the average reconstruction error was 0.7 +/- 0.2 mm, which increased to 1.1 +/- 0.5 mm when the allscans model was used. Individual and composite models did not have significantly different errors (p = 0.15, paired t-test). The average reconstruction error for the prospective models of the GTV stabilized after four measurements at 1.2 +/- 0.5 mm and for the composite model after five measurements at 0.8 +/- 0.4 mm. CONCLUSIONS: Retrospective PCA models were capable of reconstructing original GTV and lung shapes and positions within several millimeters with three to four dominant modes, on average. Prospective models achieved similar accuracy after four to five measurements.

Application of artificial neural network in prediction of bladder outlet obstruction: a model based on objective, noninvasive parameters.

OBJECTIVES: An artificial neural network model previously described by us that was based on lower urinary tract symptoms yielded a modest prediction of bladder outlet obstruction. The aim of this study was to establish another model, using more objective parameters, that could better predict for bladder outlet obstruction. METHODS: The records of 457 patients were used in the construction of the model. Of the 457 records, 300 were allocated to the training phase and 157 to the testing phase. All patients had the average flow rate, maximal flow rate, postvoid residual urine volume (PVR), and total prostate volume recorded. The results of the pressure flow study of those patients were considered the reference standard against which the artificial neural network was tested. RESULTS: Three models were tested. Models 1 and 2 were based on a three-output design (ie, nonobstructed, equivocal, and obstructed). The only difference was the number of iterations. The accuracy of the first model was 60.5% compared with 46.5% for the second. For a third model, in which the equivocal pressure flow study results were added to the nonobstructed group, the accuracy rose to 72%. Deletion of equivocal cases (around 19% of the total) was associated with an accuracy of 76% in the prediction of obstruction. CONCLUSIONS: An artificial neural network based on objective and noninvasive parameters could replace the pressure flow study in only 72% of cases. An accuracy of 76% in the detection of bladder outlet obstruction is rather impractical, because an equivocal zone has always been available on pressure flow study nomograms.

Speckle reduction in medical ultrasound: a novel scatterer density weighted nonlinear diffusion algorithm implemented as a neural-network filter.

This paper proposes a novel algorithm for speckle reduction in medical ultrasound imaging while preserving the edges with the added advantages of adaptive noise filtering and speed. We propose a nonlinear image diffusion algorithm that incorporates two local parameters of image quality, namely, scatterer density and texture-based contrast in addition to gradient, to weight the nonlinear diffusion process. The scatterer density is proposed to replace the existing traditional measures of quality of the ultrasound diffusion process such as MSE, RMSE, SNR, and PSNR. This novel diffusion filter was then implemented using back propagation neural network for fast parallel processing of volumetric images. The experimental results show that weighting the image diffusion with these parameters produces better noise reduction and produces a better edge detection quality with reasonable computational cost. The proposed filter can be used as a preprocessing phase before applying any ultrasound segmentation or active contour model processes.