Analysis of google trends and search results for ophthalmic symptoms of monkeypox.

PURPOSE: In July 2022, the World Health Organization (WHO) declared monkeypox virus's global spread a "public health emergency of international concern." About a quarter of monkeypox cases feature ophthalmic symptoms. We assessed trends in worldwide search interest in monkeypox ophthalmic involvement and inclusion in online search engine queries. METHODS: The following keywords were searched on Google Trends from April 1, 2022, to August 12, 2022: monkeypox + eye, pink eye, eye infection, eyelid, vision, blurry vision, vision loss, blindness, eye symptoms, eye problems, eye pain, eye redness, conjunctivitis, conjunctiva, cornea, keratitis, corneal ulcer, and blepharitis. We analyzed trends, correlated search interest with case count data, and compared popularity of search terms via nonparametric Mann-Whitney-U analysis. Inclusion of ophthalmic symptoms in Google search results for "monkeypox symptoms" was assessed. RESULTS: "Monkeypox eye" had the highest average search interest worldwide and in the United States. Search interest peaked between mid-May and late July 2022. When compared to interest in "monkeypox rash," the most searched monkeypox symptom, the average interest in "monkeypox eye" was lower (p < 0.01). Of the first 50 results from the Google search of "monkeypox symptoms," 10/50 (20%) mentioned ophthalmic symptoms. 6/50 (12%) mentioned the eye as a route of virus transmission. CONCLUSION: Search interest in monkeypox ophthalmic symptoms corresponds with geographic and temporal trends, i.e., timing and location of the first reported non-endemic cases and WHO announcement. Although ophthalmic symptoms are not as widely searched currently, inclusion in public health messaging is key for diagnosis, appropriate management, and reduction of further transmission.

Modeling of the Achilles Subtendons and Their Interactions in a Framework of the Absolute Nodal Coordinate Formulation.

Experimental results have revealed the sophisticated Achilles tendon (AT) structure, including its material properties and complex geometry. The latter incorporates a twisted design and composite construction consisting of three subtendons. Each of them has a nonstandard cross-section. All these factors make the AT deformation analysis computationally demanding. Generally, 3D finite solid elements are used to develop models for AT because they can discretize almost any shape, providing reliable results. However, they also require dense discretization in all three dimensions, leading to a high computational cost. One way to reduce degrees of freedom is the utilization of finite beam elements, requiring only line discretization over the length of subtendons. However, using the material models known from continuum mechanics is challenging because these elements do not usually have 3D elasticity in their descriptions. Furthermore, the contact is defined at the beam axis instead of using a more general surface-to-surface formulation. This work studies the continuum beam elements based on the absolute nodal coordinate formulation (ANCF) for AT modeling. ANCF beam elements require discretization only in one direction, making the model less computationally expensive. Recent work demonstrates that these elements can describe various cross-sections and materials models, thus allowing the approximation of AT complexity. In this study, the tendon model is reproduced by the ANCF continuum beam elements using the isotropic incompressible model to present material features.

Estimating the Characteristic Curve of a Directional Control Valve in a Combined Multibody and Hydraulic System Using an Augmented Discrete Extended Kalman Filter.

The estimation of the parameters of a simulation model such that the model's behaviour matches closely with reality can be a cumbersome task. This is due to the fact that a number of model parameters cannot be directly measured, and such parameters might change during the course of operation in a real system. Friction between different machine components is one example of these parameters. This can be due to a number of reasons, such as wear. Nevertheless, if one is able to accurately define all necessary parameters, essential information about the performance of the system machinery can be acquired. This information can be, in turn, utilised for product-specific tuning or predictive maintenance. To estimate parameters, the augmented discrete extended Kalman filter with a curve fitting method can be used, as demonstrated in this paper. In this study, the proposed estimation algorithm is applied to estimate the characteristic curves of a directional control valve in a four-bar mechanism actuated by a fluid power system. The mechanism is modelled by using the double-step semi-recursive multibody formulation, whereas the fluid power system under study is modelled by employing the lumped fluid theory. In practise, the characteristic curves of a directional control valve is described by three to six data control points of a third-order B-spline curve in the augmented discrete extended Kalman filter. The results demonstrate that the highly non-linear unknown characteristic curves can be estimated by using the proposed parameter estimation algorithm. It is also demonstrated that the root mean square error associated with the estimation of the characteristic curve is 0.08% with respect to the real model. In addition, all the errors in the estimated states and parameters of the system are within the 95% confidence interval. The estimation of the characteristic curve in a hydraulic valve can provide essential information for performance monitoring and maintenance applications.

Label-Free Evaluation of Chromatin Condensation in Human Normal Morphology Sperm Using Raman Spectroscopy.

Chromatin condensation is one of the main factors essential for sperm function. Evaluation of chromatin condensation by current methods render the assessed sperm unsuitable for assisted reproduction. We examined the Raman spectra of normal morphology sperm to determine whether a non-invasive confocal Raman spectroscopy can detect spectral differences between groups having different levels of chromatin condensation. Semen samples from 85 donors who underwent ICSI were obtained. Chromomycin A3, aniline blue and acridine orange staining were performed to evaluate the protamine deficiency, histone retention and DNA fragmentation respectively. Raman spectra were obtained from 50 normal morphology sperm for each donor. Spectral analysis was performed using home written programs in LabVIEW software and samples were grouped based on chromomycin A3 staining. Raman peaks intensities at 670 cm-1, 731 cm-1, 785 cm-1, 858 cm-1, 1062 cm-1, 1098 cm-1, 1185 cm-1, 1372 cm-1, 1424 cm-1, 1450 cm-1, 1532 cm-1, 1618 cm-1 and 1673 cm-1 were significantly correlated with at least one of the sperm staining methods. The median intensity of the Raman peaks at 670 cm-1, 731 cm-1, 785 cm-1, 1062 cm-1, 1098 cm-1, 1185 cm-1, 1372 cm-1, 1424 cm-1, 1450 cm-1, 1532 cm-1, 1618 cm-1 and 1673 cm-1 show a significant difference between the CMA3≤41 and CMA3>41groups. The Raman spectroscopic measurements represent a promising diagnostic tool that has the ability to label-free detect sperm with chromatin abnormalities, such as improper chromatin condensation and DNA fragmentation to a certain degree similar to that of the existing staining techniques at the individual cell level.

Toward Optimal Cryopreservation and Storage for Achievement of High Cell Recovery and Maintenance of Cell Viability and T Cell Functionality.

Cryopreservation of biological materials such as cells, tissues, and organs is a prevailing topic of high importance. It is employed not only in many research fields but also in the clinical area. Cryopreservation is of great importance for reproductive medicine and clinical studies, as well as for the development of vaccines. Peripheral blood mononuclear cells (PBMCs) are commonly used in vaccine research where comparable and reliable results between different research institutions and laboratories are of high importance. Whereas freezing and thawing processes are well studied, controlled, and standardized, storage conditions are often disregarded. To close this gap, we investigated the influence of suboptimal storage conditions during low-temperature storage on PBMC viability, recovery, and T cell functionality. For this purpose, PBMCs were isolated and exposed with help of a robotic system in a low-temperature environment from 0 up to 350 temperature fluctuation cycles in steps of 50 cycles to simulate storage conditions in large biorepositories with sample storage, removal, and sorting functions. After the simulation, the viability, recovery, and T cell functionality were analyzed to determine the number of temperature rises, which ultimately lead to significant cell damage. All studied parameters decreased with increasing number of temperature cycles. Sometimes after as little as only 50 temperature cycles, a significant effect was observed. These results are very important for all fields in which cell cryopreservation is employed, particularly for clinical and multicenter studies wherein the comparability and reproducibility of results play a crucial role. To obtain reliable results and to maintain the quality of the cells, not only the freezing and thawing processes but also the storage conditions should be controlled and standardized, and any deviations should be documented.

The RNA-binding protein quaking maintains endothelial barrier function and affects VE-cadherin and ß-catenin protein expression.

Proper regulation of endothelial cell-cell contacts is essential for physiological functioning of the endothelium. Interendothelial junctions are actively involved in the control of vascular leakage, leukocyte diapedesis, and the initiation and progression of angiogenesis. We found that the RNA-binding protein quaking is highly expressed by endothelial cells, and that its expression was augmented by prolonged culture under laminar flow and the transcription factor KLF2 binding to the promoter. Moreover, we demonstrated that quaking directly binds to the mRNA of VE-cadherin and ß-catenin and can induce mRNA translation mediated by the 3'UTR of these genes. Reduced quaking levels attenuated VE-cadherin and ß-catenin expression and endothelial barrier function in vitro and resulted in increased bradykinin-induced vascular leakage in vivo. Taken together, we report that quaking is essential in maintaining endothelial barrier function. Our results provide novel insight into the importance of post-transcriptional regulation in controlling vascular integrity.

A fibre-reinforced poroviscoelastic model accurately describes the biomechanical behaviour of the rat Achilles tendon.

BACKGROUND: Computational models of Achilles tendons can help understanding how healthy tendons are affected by repetitive loading and how the different tissue constituents contribute to the tendon's biomechanical response. However, available models of Achilles tendon are limited in their description of the hierarchical multi-structural composition of the tissue. This study hypothesised that a poroviscoelastic fibre-reinforced model, previously successful in capturing cartilage biomechanical behaviour, can depict the biomechanical behaviour of the rat Achilles tendon found experimentally. MATERIALS AND METHODS: We developed a new material model of the Achilles tendon, which considers the tendon's main constituents namely: water, proteoglycan matrix and collagen fibres. A hyperelastic formulation of the proteoglycan matrix enabled computations of large deformations of the tendon, and collagen fibres were modelled as viscoelastic. Specimen-specific finite element models were created of 9 rat Achilles tendons from an animal experiment and simulations were carried out following a repetitive tensile loading protocol. The material model parameters were calibrated against data from the rats by minimising the root mean squared error (RMS) between experimental force data and model output. RESULTS AND CONCLUSIONS: All specimen models were successfully fitted to experimental data with high accuracy (RMS 0.42-1.02). Additional simulations predicted more compliant and soft tendon behaviour at reduced strain-rates compared to higher strain-rates that produce a stiff and brittle tendon response. Stress-relaxation simulations exhibited strain-dependent stress-relaxation behaviour where larger strains produced slower relaxation rates compared to smaller strain levels. Our simulations showed that the collagen fibres in the Achilles tendon are the main load-bearing component during tensile loading, where the orientation of the collagen fibres plays an important role for the tendon's viscoelastic response. In conclusion, this model can capture the repetitive loading and unloading behaviour of intact and healthy Achilles tendons, which is a critical first step towards understanding tendon homeostasis and function as this biomechanical response changes in diseased tendons.

Correction of Gradient Nonlinearity Bias in Quantitative Diffusion Parameters of Renal Tissue with Intra Voxel Incoherent Motion.

Spatially non-uniform diffusion weighting bias due to gradient nonlinearity (GNL) causes substantial errors in apparent diffusion coefficient (ADC) maps for anatomical regions imaged distant from magnet isocenter. Our previously-described approach allowed effective removal of spatial ADC bias from three orthogonal DWI measurements for mono-exponential media of arbitrary anisotropy. The present work evaluates correction feasibility and performance for quantitative diffusion parameters of the two-component IVIM model for well-perfused and nearly isotropic renal tissue. Sagittal kidney DWI scans of a volunteer were performed on a clinical 3T MRI scanner near isocenter and offset superiorly. Spatially non-uniform diffusion weighting due to GNL resulted both in shift and broadening of perfusion-suppressed ADC histograms for off-center DWI relative to unbiased measurements close to isocenter. Direction-average DW-bias correctors were computed based on the known gradient design provided by vendor. The computed bias maps were empirically confirmed by coronal DWI measurements for an isotropic gel-flood phantom. Both phantom and renal tissue ADC bias for off-center measurements was effectively removed by applying pre-computed 3D correction maps. Comparable ADC accuracy was achieved for corrections of both b-maps and DWI intensities in presence of IVIM perfusion. No significant bias impact was observed for IVIM perfusion fraction.

Hematopoietic microRNA-126 protects against renal ischemia/reperfusion injury by promoting vascular integrity.

Ischemia/reperfusion injury (IRI) is a central phenomenon in kidney transplantation and AKI. Integrity of the renal peritubular capillary network is an important limiting factor in the recovery from IRI. MicroRNA-126 (miR-126) facilitates vascular regeneration by functioning as an angiomiR and by modulating mobilization of hematopoietic stem/progenitor cells. We hypothesized that overexpression of miR-126 in the hematopoietic compartment could protect the kidney against IRI via preservation of microvascular integrity. Here, we demonstrate that hematopoietic overexpression of miR-126 increases neovascularization of subcutaneously implanted Matrigel plugs in mice. After renal IRI, mice overexpressing miR-126 displayed a marked decrease in urea levels, weight loss, fibrotic markers, and injury markers (such as kidney injury molecule-1 and neutrophil gelatinase-associated lipocalin). This protective effect was associated with a higher density of the peritubular capillary network in the corticomedullary junction and increased numbers of bone marrow-derived endothelial cells. Hematopoietic overexpression of miR-126 increased the number of circulating Lin(-)/Sca-1(+)/cKit(+) hematopoietic stem and progenitor cells. Additionally, miR-126 overexpression attenuated expression of the chemokine receptor CXCR4 on Lin(-)/Sca-1(+)/cKit(+) cells in the bone marrow and increased renal expression of its ligand stromal cell-derived factor 1, thus favoring mobilization of Lin(-)/Sca-1(+)/cKit(+) cells toward the kidney. Taken together, these results suggest overexpression of miR-126 in the hematopoietic compartment is associated with stromal cell-derived factor 1/CXCR4-dependent vasculogenic progenitor cell mobilization and promotes vascular integrity and supports recovery of the kidney after IRI.

Diffusion-weighted MRI of metastatic liver lesions: is there a difference between hypervascular and hypovascular metastases?

BACKGROUND: Different perfusion characteristics and histopathologic features of liver metastasis may potentially lead to different diffusion-weighted magnetic resonance imaging (DW-MRI) characteristics which can affect the performance of DW-MRI in their diagnosis. PURPOSE: To compare ADC values of hypervascular and hypovascular metastases and the added value of DW-MRI to T2-weighted (T2-w) images in their detection. MATERIAL AND METHODS: In this retrospective study, 46 patients (21 with hypervascular, 25 with hypovascular liver metastases) who had undergone abdominal MRI were included. Two independent observers first reviewed T2-w images only and then T2-w+DW-MR images and recorded number of metastases in each session. Lesion detection rate was compared using McNemar test. ADC of metastases in each patient was measured and compared between hypo- and hypervascular lesions using t-test. RESULTS: A total of 153 hypervascular and 187 hypovascular metastases were detected at consensus review. Two observers detected significantly more hypervascular metastases on T2-w+DW-MR image review session compared to T2-w image only review session (reader 1: 148 [96.7%] vs. 129 [84.3%], P=0.002; reader 2: 125 [81.9%] vs. 113 [73.8%], P=0.004). Detection rate of hypovascular metastases was similar between two sessions for both observers (reader 1: 180 [96.2%] vs. 184 [98.4%]; reader 2: 176 [94.1%] vs. 180 [96.2%], P>0.05). The mean ADC value of hypervascular metastases was significantly lower than mean ADC value of hypovascular metastases (1.23+/-0.31 × 10(-3)mm(2)/s vs. 1.49+/-0.19 × 10(-3)mm(2)/s) (P=0.001). CONCLUSION: Liver metastases are not a homogenous group of lesions with uniform DW-MRI features. Hypervascular metastases demonstrate significantly lower ADC values compared to hypovascular metastases. DW-MRI improved detection of hypervascular metastases compared to T2-w images alone and is a useful adjunct to T2-w images for their detection.

Hybrid multidimensional T(2) and diffusion-weighted MRI for prostate cancer detection.

PURPOSE: To study the dependence of apparent diffusion coefficient (ADC) and T2 on echo time (TE) and b-value, respectively, in normal prostate and prostate cancer, using two-dimensional MRI sampling, referred to as "hybrid multidimensional imaging." MATERIALS AND METHODS: The study included 10 patients with biopsy-proven prostate cancer who underwent 3 Tesla prostate MRI. Diffusion-weighted MRI (DWI) data were acquired at b = 0, 750, and 1500 s/mm(2) . For each b-value, data were acquired at TEs of 47, 75, and 100 ms. ADC and T2 were measured as a function of b-value and TE, respectively, in 15 cancer and 10 normal regions of interest (ROIs). The Friedman test was used to test the significance of changes in ADC as a function of TE and of T2 as a function of b-value. RESULTS: In normal prostate ROIs, the ADC at TE of 47 ms is significantly smaller than ADC at TE of 100 ms (P = 0.0003) and T2 at b-value of 0 s/mm(2) is significantly longer than T2 at b-value of 1500 s/mm(2) (P = 0.001). In cancer ROIs, average ADC and T2 values do not change as a function of TE and b-value, respectively. However, in many cancer pixels, there are large decreases in the ADC as a function of TE and large increases in T2 as a function of b-value. Cancers are more conspicuous in ADC maps at longer TEs. CONCLUSION: Parameters derived from hybrid imaging that depend on coupled/associated values of ADC and T2 may improve the accuracy of MRI in diagnosing prostate cancer.

Quaking, an RNA-binding protein, is a critical regulator of vascular smooth muscle cell phenotype.

RATIONALE: RNA-binding proteins are critical post-transcriptional regulators of RNA and can influence pre-mRNA splicing, RNA localization, and stability. The RNA-binding protein Quaking (QKI) is essential for embryonic blood vessel development. However, the role of QKI in the adult vasculature, and in particular in vascular smooth muscle cells (VSMCs), is currently unknown. OBJECTIVE: We sought to determine the role of QKI in regulating adult VSMC function and plasticity. METHODS AND RESULTS: We identified that QKI is highly expressed by neointimal VSMCs of human coronary restenotic lesions, but not in healthy vessels. In a mouse model of vascular injury, we observed reduced neointima hyperplasia in Quaking viable mice, which have decreased QKI expression. Concordantly, abrogation of QKI attenuated fibroproliferative properties of VSMCs, while potently inducing contractile apparatus protein expression, rendering noncontractile VSMCs with the capacity to contract. We identified that QKI localizes to the spliceosome, where it interacts with the myocardin pre-mRNA and regulates the splicing of alternative exon 2a. This post-transcriptional event impacts the Myocd_v3/Myocd_v1 mRNA balance and can be modulated by mutating the quaking response element in exon 2a of myocardin. Furthermore, we identified that arterial damage triggers myocardin alternative splicing and is tightly coupled with changes in the expression levels of distinct QKI isoforms. CONCLUSIONS: We propose that QKI is a central regulator of VSMC phenotypic plasticity and that intervention in QKI activity can ameliorate pathogenic, fibroproliferative responses to vascular injury.

Breast MR imaging at 3 T with dual-source radiofrequency transmission offers superior B1 homogeneity: an intraindividual comparison with breast MR imaging at 1.5 T.

PURPOSE: To evaluate and compare B1 homogeneity for breast magnetic resonance (MR) imaging performed at 3 T with dual-source radiofrequency (RF) transmission to 1.5-T MR imaging and 3-T MR imaging with quadrature transmission. MATERIALS AND METHODS: This prospective study received institutional review board approval and patients provided informed consent. Women (n = 25; mean age, 53 years; range, 30-68 years) suspected of having breast lesions underwent breast MR imaging examinations on comparable 1.5-T and 3-T clinical systems between February and May 2012. B1 maps were obtained at 1.5 T and at 3 T with quadrature and dual-source RF transmission. Intrabreast differences and differences in mean B1 values between right and left breasts were investigated by using two-sided multivariate analysis of variance with interaction; t tests were used to compare the differences between measured whole-breast mean B1 values and requested B1 values. RESULTS: With quadrature transmission at 1.5 T and 3 T, the mean B1 values showed a statistically significant difference: left-breast measured B1 was -8.9% of requested B1 value at 1.5 T and -13.7% at 3 T (P < .001), whereas right-breast measured B1 was +5.4% of requested B1 value at 1.5 T (P < .001) and +2.7% at 3 T (P = .01). With dual-source RF transmission at 3 T, mean B1 values across the breasts were not statistically different, nor were the measured B1 values compared with requested B1 values (left breast, -0.6%; right breast, -0.7%). At 3 T with dual-source transmission, slight intrabreast local variations in B1 were recorded. CONCLUSION: MR imaging at 3 T with dual-source RF transmission offered an overall B1 homogeneity for breast imaging that was better than that obtained at 1.5 T and with quadrature transmission.

Combined effects of sensory cueing and limb activation on unilateral neglect in subacute left hemiplegic stroke patients: a randomized controlled pilot study.

OBJECTIVE: To compare the effects of contralesional sensory cueing and limb activation with that of sham control in the treatment of unilateral neglect after stroke. DESIGN: A randomized, single-blinded, sham-controlled pilot study. SETTING: Two rehabilitation hospitals. SUBJECTS: Forty subacute left hemiplegic stroke inpatients with unilateral neglect. INTERVENTIONS: Participants were assigned randomly to 1 of 2 groups. The experimental group wore a wristwatch cueing device over the hemiplegic arm for three hours a day, five days per week, for three weeks, and also underwent conventional rehabilitation. Patients were encouraged to move their hemiplegic arm five consecutive times after each prompt. The sham group underwent the same rehabilitation process, except they wore a sham device. MAIN MEASURES: Neglect, arm motor performance, and overall functioning were assessed pre- and posttraining, and at follow-up. RESULTS: There were no significant differences between groups in outcome measures except the neglect drawing tasks (p = 0.034) (the mean gain score from baseline to follow-up assessment was 5.2 (3.7) in the experimental group and 1.9 (3.5) in the sham group), across three time intervals. The experimental group showed greater improvement in arm motor performance than did the sham group. CONCLUSION: The results did not confirm that sensory cueing and limb activation treatment is effective when compared with those receiving placebo to reduce unilateral neglect, but it might be useful for promoting hemiplegic arm performance in stroke patients.

MR imaging-guided focal laser ablation for prostate cancer: phase I trial.

PURPOSE: To evaluate the feasibility and safety of magnetic resonance (MR) imaging-guided laser-based thermotherapy in men with clinically low-risk prostate cancer and a concordant lesion at biopsy and MR imaging. MATERIALS AND METHODS: This HIPAA-compliant phase I prospective study was approved by the institutional review board. Informed consent was obtained from all patients. Transperineal MR imaging-guided focal laser ablation for clinically low-risk prostate cancer was performed in patients with a Gleason score of 7 or less in three or fewer cores limited to one sextant obtained with transrectal ultrasonography (US)-guided biopsy and a concordant lesion at MR imaging. Lesions were targeted with a laser ablation system. Periprocedural complications were recorded. The International Prostate Symptom Score (IPSS) and the Sexual Health Inventory for Men (SHIM) score were collected before and after the procedure. MR imaging-guided biopsy of the ablation zone was performed 6 months after treatment. The prostate-specific antigen level, IPSS, and SHIM score before and after ablation were compared by using the Wilcoxon signed rank test. RESULTS: Treatment was successfully completed in nine patients (procedure duration, 2.5-4 hours; mean laser ablation duration, 4.3 minutes). Immediate contrast-enhanced posttreatment MR imaging showed a hypovascular defect in eight patients. Self-resolving perineal abrasion and focal paresthesia of the glans penis each occurred in one patient. The mean (± standard deviation) IPSS and SHIM score at baseline were 5.8 ± 5.3 and 19.0 ± 8.0, respectively. Average score changes were not significantly different from zero during follow-up (P = .18-.99). MR imaging-guided biopsy of the ablation zone showed no cancer in seven patients (78%) and Gleason grade 6 cancer in two (22%). CONCLUSION: Transperineal MR imaging-guided focal laser ablation appears to be a feasible and safe focal therapy option for clinically low-risk prostate cancer.

Classification of breast lesions pre-contrast injection using water resonance lineshape analysis.

Inhomogeneously broadened, non-Lorentzian water resonances have been observed in small image voxels of breast tissue. The non-Lorentzian components of the water resonance are probably produced by bulk magnetic susceptibility shifts caused by dense, deoxygenated tumor blood vessels (the 'blood oxygenation level-dependent' effect), but can also be produced by other characteristics of local anatomy and physiology, including calcifications and interfaces between different types of tissue. Here, we tested the hypothesis that the detection of non-Lorentzian components of the water resonance with high spectral and spatial resolution (HiSS) MRI allows the classification of breast lesions without the need to inject contrast agent. Eighteen malignant lesions and nine benign lesions were imaged with HiSS MRI at 1.5 T. A new algorithm was developed to detect non-Lorentzian (or off-peak) components of the water resonance. After a Lorentzian fit had been subtracted from the data, the largest peak in the residual spectrum in each voxel was identified as the major off-peak component of the water resonance. The difference in frequency between these off-peak components and the main water peaks, and their amplitudes, were measured in malignant lesions, benign lesions and breast fibroglandular tissue. Off-peak component frequencies were significantly different between malignant and benign lesions (p < 0.001). Receiver operating characteristic (ROC) analysis was used to assess the diagnostic performance of HiSS off-peak component analysis compared with dynamic contrast-enhanced (DCE) MRI parameters. The areas under the ROC curves for the 'DCE rapid uptake fraction', 'DCE washout fraction', 'off-peak component amplitude' and 'off-peak component frequency' were 0.75, 0.83, 0.50 and 0.86, respectively. These results suggest that water resonance lineshape analysis performs well in the classification of breast lesions without contrast injection and could improve the diagnostic accuracy of clinical breast MR examinations. In addition, this approach may provide an alternative to DCE MRI in women who are at risk for adverse reactions to contrast media.

Non-contrast enhanced MRI for evaluation of breast lesions: comparison of non-contrast enhanced high spectral and spatial resolution (HiSS) images versus contrast enhanced fat-suppressed images.

RATIONALE AND OBJECTIVES: The aims of this study were to evaluate high spectral and spatial resolution (HiSS) magnetic resonance imaging (MRI) for the diagnosis of breast cancer without the injection of contrast media by comparing the performance of precontrast HiSS images to that of conventional contrast-enhanced, fat-suppressed, T1-weighted images on the basis of image quality and in the task of classifying benign and malignant breast lesions. MATERIALS AND METHODS: Ten benign and 44 malignant lesions were imaged at 1.5 T with HiSS (precontrast administration) and conventional fat-suppressed imaging (3-10 minutes after contrast administration). This set of 108 images, after randomization, was evaluated by three experienced radiologists blinded to the imaging technique. Breast Imaging Reporting and Data System morphologic criteria (lesion shape, lesion margin, and internal signal intensity pattern) and final assessment were used to measure reader performance. Image quality was evaluated on the basis of boundary delineation and quality of fat suppression. An overall probability of malignancy was assigned to each lesion for HiSS and conventional images separately. RESULTS: On boundary delineation and quality of fat suppression, precontrast HiSS scored similarly to conventional postcontrast MRI. On benign versus malignant lesion separation, there was no statistically significant difference in receiver-operating characteristic performance between HiSS and conventional MRI, and HiSS met a reasonable noninferiority condition. CONCLUSIONS: Precontrast HiSS imaging is a promising approach for showing lesion morphology without blooming and other artifacts caused by contrast agents. HiSS images could be used to guide subsequent dynamic contrast-enhanced MRI scans to maximize spatial and temporal resolution in suspicious regions. HiSS MRI without contrast agent injection may be particularly important for patients at risk for contrast-induced nephrogenic systemic fibrosis or allergic reactions.

Diffusion coefficient measurement using a temperature-controlled fluid for quality control in multicenter studies.

PURPOSE: To present the use of a quality control ice-water phantom for diffusion-weighted magnetic resonance imaging (DW-MRI). DW-MRI has emerged as an important cancer imaging biomarker candidate for diagnosis and early treatment response assessment. Validating imaging biomarkers through multicenter trials requires calibration and performance testing across sites. MATERIALS AND METHODS: The phantom consisted of a center tube filled with distilled water surrounded by ice water. Following preparation of the phantom, ≈30 minutes was allowed to reach thermal equilibrium. DW-MRI data were collected at seven institutions, 20 MRI scanners from three vendors, and two field strengths (1.5 and 3T). The phantom was also scanned on a single system on 16 different days over a 25-day period. All data were transferred to a central processing site at the University of Michigan for analysis. RESULTS: Results revealed that the variation of measured apparent diffusion coefficient (ADC) values between all systems tested was ±5%, indicating excellent agreement between systems. Reproducibility of a single system over a 25-day period was also found to be within ±5% ADC values. Overall, the use of an ice-water phantom for assessment of ADC was found to be a reasonable candidate for use in multicenter trials. CONCLUSION: The ice-water phantom described here is a practical and universal approach to validate the accuracy of ADC measurements with ever changing MRI sequence and hardware design and can be readily implemented in multicenter clinical trial designs.

Echo-planar spectroscopic imaging (EPSI) of the water resonance structure in human breast using sensitivity encoding (SENSE).

High spectral and spatial resolution MRI, based on echo-planar spectroscopic imaging, has been applied successfully in diagnostic breast imaging, but acquisition times are long. One way of increasing acquisition speed is to apply the sensitivity encoding algorithm for complex high spectral and spatial resolution data. We demonstrate application of a complex sensitivity encoding algorithm to high spectral and spatial resolution MRI data, in a phantom and human breast, with 7- and 16-channel dedicated breast phased-array coils. Very low g factors are obtained using the breast coils, and the signal-to-noise ratio (SNR) penalty for water resonance peak height and water resonance asymmetry images is small at acceleration factors of up to 6 and 4, respectively, as evidenced by high Pearson correlation factors between fully sampled and accelerated data. This is the first application of the sensitivity encoding algorithm to characterize the structure of the water resonance at high spatial resolution.

Subword-based semantic retrieval of clinical and bibliographic documents.

OBJECTIVES: The increasing amount of electronically available documents in bibliographic databases and the clinical documentation requires user-friendly techniques for content retrieval. METHODS: A domain-specific approach on semantic text indexing for document retrieval is presented. It is based on a subword thesaurus and maps the content of texts in different European languages to a common interlingual representation, which supports the search across multilingual document collections. RESULTS: Three use cases are presented where the semantic retrieval method has been implemented: a bibliographic database, a department EHR system, and a consumer-oriented Web portal. CONCLUSIONS: It could be shown that a semantic indexing and retrieval approach, the performance of which had already been empirically assessed in prior studies, proved useful in different prototypical and routine scenarios and was well accepted by several user groups.