Quantitative Diagnostic Information Research Articles

The effect of shear wave elastography in the diagnosis of delaminated partial-thickness rotator cuff tears.

To assess the effectiveness of shear wave elastography (SWE) in diagnosing delaminated partial-thickness rotatorcuff tears (DPT-RCT). A retrospective study was carried out on 137 patients with DPT-RCT. Thestudy included complete clinical data, including the images of conventional ultrasound (US), SWE, Magnetic Resonance Imaging (MRI) and shoulder arthroscopic surgery. The features of US, SWE, and MRI were evaluated. The study analysed theShear-Wave Velocity (SWV) among three types of DPT-RCT, and between the regions of tears, normal contralateral, and affected unilateral supraspinatus tendon. Furthermore, receiver operating characteristic (ROC) curves were evaluated. The SWE detection rate was significantly higher (91.2%) compared to US (73.7%) and MRI (87.6%) for the overall diagnosisof DPT-RCT. Similarly, SWE yielded higher rates of detection for types 1 (89.5%) and 2 (92.3%) of DPT-RCT as comparedto US (71.7%, 69.2%) and MRI (81.6%, 94.9%), respectively. However, there was no significant difference in the accuracy ofdiagnosing type 3 among the three methods. The SWV of the 137 supraspinatus tendon tears was 3.64±0.60 m/s, which was higher than that of the normal supraspinatus tendon (2.43±0.47 m/s, p<0.01) as well as the region of tears (1.61±0.54 m/s, p<0.01). Nevertheless, there was no significant difference in SWV among the three types of DPT-RCT. The cutoff thresholds ofSWV for identifying normal tendon from DPT-RCT and for identifying DPT-RCT from the region of tears were 2.96m/s and2.39m/s, respectively. SWE with SWV can provide both quantitative and qualitative diagnostic information for DPT-RCT, which can be used as a crucial supplement imaging method.

(Digital Presentation) Development of an Electrochemical Microfluidic Device with on-Platform Sample Collection

As the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to develop, the need for portable rapid testing platforms remains prevalent to provide patients with accurate and quantitative diagnostic and serosurveillance information at the point-of-care. The current gold standard detection techniques like RT-PCR and ELISA require trained personnel to perform lengthy protocols, resulting in a long turnover from sample collection to result acquisition. Herein, we propose an electrochemical microfluidic device for on-platform detection of viral proteins and antibodies at the point-of-care in a multiplexed manner. Miniaturization technology through the use of microfluidic devices offers numerous advantages including low reagent consumption, high fluidic control, reduced reaction times, inexpensive applications, and the possibility of throughput analysis. Electrochemical detection can provide advantages in cost effective fabrication, high sensitivity and simple instrumentation using a standard 3-electrode (working, reference, and counter) setup. Our platform proposes the design of an electrochemical cell with an enhanced working electrode to act as the detection assay with microfluidic channels to facilitate sample collection and pre-treatment; an integrated saliva collection kit and lancing device enabled the use of both untreated saliva from direct self-collection and whole blood from a finger prick. Automated fluid manipulation reduced the potential of user contamination through the implementation of suction-based flow. The electrochemical microfluidic device was encased in a 3D-printed cartridge for the fabrication of a fully integrative technology on a single platform with the potential to be used at the point-of-care in both clinical and commercial applications using direct biofluids.

The Role of 2-Dimensional Speckle Tracking Echocardiography in prediction of significant coronary artery

Background: Speckle tracking echocardiography is new technique to evaluate left ventricular function.Objective: To evaluate sensitivity and specificity of two dimension global longitudinal strain ( 2D-GLS) estimated by speckle tracking echocardiography (2D-STE) to predict the diagnosis and degree of severity of CAD( coronary artery disease) in patient suspected to have stable ischemic heart diseases (IHD).Patients and Methods: An observational cross-sectional study, patients underwent echocardiography (TTE), left ventricular (LV)systolic function were estimate initially, (calculate LVEF) then assessment of LV global and regional longitudinal strain (GLS) were calculated next.All patient underwent coronary angiography in the catheterization unite and according to the result of coronary angiography, we separated patients into two groups: one how have significant (≥70%) coronary arteries stenosis (group A),and another group with non- significant(&lt;70%) coronary arteries stenosis (group B). The study was done in echocardiography unit and catheterization lab in Ibn-Albitar center of cardiac surgery, the study carried out from April 2018 to May 2019. Results: This study 93 patients were included , there is mean ages was (60.2 ±6.3) years, majority of cases were males (72.0%), 47.3% of all cases had ≥3 risk factors, and according to angiography study (67.7%) had significant CAD .The frequency of DM, dyslipidemia, and the occurrence of ≥3 risk factors were significantly elevated in group A(patients with significant coronary artery stenosis ) in comparison to the group B. Mean EF and GLS were considerably lower in group A related to group B. There was not much difference in GLS between single and two vessels involvement, however, the GLS value in three vessels was significantly lower compared to single and two vessels involvement. GLS were independent predictor of significant coronary artery stenosis, independent of the effect DM, dyslipidemia, and the presence of ≥3 concomitant risk factor. Conclusion: Assessment (GLS) value by 2D speckle tracking echocardiography is good test for predicating diagnostic and severity of coronary arteries diseases, global longitudinal strain had positive relationship with increasing number of stenotic coronary arteries, and provides high quantitative diagnostic information for detection of the CAD. Keywords: Echocardiography, significant coronary artery disease

In vivo quantitative analysis of anterior chamber white blood cell mixture composition using spectroscopic optical coherence tomography.

Anterior uveitis is the most common form of intraocular inflammation, and one of its main signs is the presence of white blood cells (WBCs) in the anterior chamber (AC). Clinically, the true composition of cells can currently only be obtained using AC paracentesis, an invasive procedure to obtain AC fluid requiring needle insertion into the AC. We previously developed a spectroscopic optical coherence tomography (SOCT) analysis method to differentiate between populations of RBCs and subtypes of WBCs, including granulocytes, lymphocytes and monocytes, both in vitro and in ACs of excised porcine eyes. We have shown that different types of WBCs have distinct characteristic size distributions, extracted from the backscattered reflectance spectrum of individual cells using Mie theory. Here, we further develop our method to estimate the composition of blood cell mixtures, both in vitro and in vivo. To do so, we estimate the size distribution of unknown cell mixtures by fitting the distribution observed using SOCT with a weighted combination of reference size distributions of each WBC type calculated using kernel density estimation. We validate the accuracy of our estimation in an in vitro study, by comparing our results for a given WBC sample mixture with the cellular concentrations measured by a hemocytometer and SOCT images before mixing. We also conducted a small in vivo quantitative cell mixture validation pilot study which demonstrates congruence between our method and AC paracentesis in two patients with uveitis. The SOCT based method appears promising to provide quantitative diagnostic information of cellular responses in the ACs of patients with uveitis.

Navigated TMS in the ICU: Introducing Motor Mapping to the Critical Care Setting.

Navigated transcranial magnetic stimulation (nTMS) is a modality for noninvasive cortical mapping. Specifically, nTMS motor mapping is an objective measure of motor function, offering quantitative diagnostic information regardless of subject cooperation or consciousness. Thus far, it has mostly been restricted to the outpatient setting. This study evaluates the feasibility of nTMS motor mapping in the intensive care unit (ICU) setting and solves the challenges encountered in this special environment. We compared neuronavigation based on computed tomography (CT) and magnetic resonance imaging (MRI). We performed motor mappings in neurocritical patients under varying conditions (e.g., sedation or hemicraniectomy). Furthermore, we identified ways of minimizing electromyography (EMG) noise in the interference-rich ICU environment. Motor mapping was performed in 21 patients (six females, median age: 69 years). In 18 patients, motor evoked potentials (MEPs) were obtained. In three patients, MEPs could not be evoked. No adverse reactions occurred. We found CT to offer a comparable neuronavigation to MRI (CT maximum e-field 52 ± 14 V/m vs. MRI maximum e-field 52 ± 11 V/m; p = 0.6574). We detailed EMG noise reduction methods and found that propofol sedation of up to 80 mcg/kg/h did not inhibit MEPs. Yet, nTMS equipment interfered with exposed pulse oximetry. nTMS motor mapping application and use was illustrated in three clinical cases. In conclusion, we present an approach for the safe and reliable use of nTMS motor mapping in the ICU setting and outline possible benefits. Our findings support further studies regarding the clinical value of nTMS in critical care settings.

Hyperspectral Imaging (HSI) of Human Kidney Allografts.

Aim of our study was to test a noninvasive HSI technique as an intraoperative real time assessment tool for deceased donor kidney quality and function in human kidney allotransplantation. HSI is capable to deliver quantitative diagnostic information about tissue pathology, morphology, and composition, based on the spectral characteristics of the investigated tissue. Because tools for objective intraoperative graft viability and performance assessment are lacking, we applied this novel technique to human kidney transplantation. Hyperspectral images of distinct components of kidney allografts (parenchyma, ureter) were acquired 15 and 45 minutes after reperfusion and subsequently analyzed using specialized HSI acquisition software capable to compute oxygen saturation levels (StO2), near infrared perfusion indices (NIR), organ hemoglobin indices, and tissue water indices of explored tissues. Seventeen kidney transplants were analyzed. Median recipient and donor age were 55 years. Cold ischemia time was 10.8 ± 4.1 hours and anastomosis time was 35 ± 7 minutes (mean ± standard deviation). Two patients (11.8%) developed delayed graft function (DGF). cold ischemia time was significantly longer (18.6 ± 1.6) in patients with DGF (P < 0.01). Kidneys with DGF furthermore displayed significant lower StO2 (P = 0.02) and NIR perfusion indices, 15 minutes after reperfusion (P < 0.01). Transplant ureters displayed a significant decrease of NIR perfusion with increased distance to the renal pelvis, identifying well and poor perfused segments. Intraoperative HSI is feasible and meaningful to predict DGF in renal allografts. Furthermore, it can be utilized for image guided surgery, providing information about tissue oxygenation, perfusion, hemoglobin concentration, and water concentration, hence allowing intraoperative viability assessment of the kidney parenchyma and the ureter.

Comparison of spectral characteristics in human and pig biliary system with hyperspectral imaging (HSI)

Abstract Injuries to the biliary tree during surgical, endoscopic or invasive radiological diagnostic or therapeutic procedures involving the pancreas, liver or organs of the upper gastrointestinal tract give rise to the need to develop a method for clear discrimination of biliary anatomy from surrounding tissue. Hyperspectral imaging (HSI) is an emerging optical technique in disease diagnosis and image-guided surgery with inherent advantages of being a non-contact, non-invasive, and non-ionizing technique. HSI can produce quantitative diagnostic information about tissue pathology, morphology, and chemical composition. HSI was applied in human liver transplantation and compared to porcine model operations to assess the capability of discriminating biliary anatomy from surrounding biological tissue. Absorbance spectra measured from bile ducts, gall bladder, and liver show a dependence on tissue composition and bile concentration, with agreement between human and porcine datasets. The bile pigment biliverdin and structural proteins collagen and elastin were identified as contributors to the bile duct and gall bladder absorbance spectra.

Tensor image enhancement and optimal multichannel receiver combination analyses for human hyperpolarized 13 C MRSI.

With the initiation of human hyperpolarized 13 C (HP-13 C) trials at multiple sites and the development of improved acquisition methods, there is an imminent need to maximally extract diagnostic information to facilitate clinical interpretation. This study aims to improve human HP-13 C MR spectroscopic imaging through means of Tensor Rank truncation-Image enhancement (TRI) and optimal receiver combination (ORC). A data-driven processing framework for dynamic HP 13 C MR spectroscopic imaging (MRSI) was developed. Using patient data sets acquired with both multichannel arrays and single-element receivers from the brain, abdomen, and pelvis, we examined the theory and application of TRI, as well as 2 ORC techniques: whitened singular value decomposition (WSVD) and first-point phasing. Optimal conditions for TRI were derived based on bias-variance trade-off. TRI and ORC techniques together provided a 63-fold mean apparent signal-to-noise ratio (aSNR) gain for receiver arrays and a 31-fold gain for single-element configurations, which particularly improved quantification of the lower-SNR-[13 C]bicarbonate and [1-13 C]alanine signals that were otherwise not detectable in many cases. Substantial SNR enhancements were observed for data sets that were acquired even with suboptimal experimental conditions, including delayed (114 s) injection (8× aSNR gain solely by TRI), or from challenging anatomy or geometry, as in the case of a pediatric patient with brainstem tumor (597× using combined TRI and WSVD). Improved correlation between elevated pyruvate-to-lactate conversion, biopsy-confirmed cancer, and mp-MRI lesions demonstrated that TRI recovered quantitative diagnostic information. Overall, this combined approach was effective across imaging targets and receiver configurations and could greatly benefit ongoing and future HP 13 C MRI research through major aSNR improvements.

The predictive value of speckle tracking during dobutamine stress echocardiography in patients with chronic stable angina

ObjectiveEvaluation of the diagnostic value of speckle tracking echocardiography (STE) at rest and during dobutamine stress in predicting the presence and severity of coronary artery disease (CAD) in patients with chronic stable angina. MethodsA total of 100 patients with chronic stable angina were evaluated using STE at rest and during dobutamine stress to detect the presence, severity, and number of affected coronary arteries. Then, the correlation with the SYNTAX score (SS) was analyzed. ResultsSTE at stress showed better agreement with coronary angiography (CA) than dobutamine stress echocardiography (DSE) in detecting the presence of coronary artery stenosis (Kappa = 0.819, p < 0.001). STE at stress suggested involvement of the left anterior descending artery (LAD) with excellent agreement with CA (Kappa = 0.816, p < 0.001). For right coronary artery, STE at rest and stress showed good agreement with the CA results (Kappa = 0.775 and 0.858, respectively, p < 0.001), whereas for left circumflex artery, STE at rest and stress showed a fair agreement with the CA results (Kappa = 0.556 and 0.583, respectively, p < 0.001). Resting global longitudinal peak systolic strain (GLPSS) ≥ −15.2% had the best diagnostic accuracy (sensitivity = 61.8%; specificity = 93.5%) in predicting SS > 22. Stress GLPSS ≥ −12.5% had the best diagnostic accuracy (sensitivity = 82.4%; specificity = 78.3%) in predicting SS > 22. ConclusionSpeckle tracking during DSE has high sensitivity and specificity for predicting the presence of CAD. It provides quantitative diagnostic information that decreases the false positive and false negative results of DSE.

Blood CT pefusion analysis of cerebral gray matter and white matter in supply region of chronic cerebral artery occlusion

Objective To study the different ischemic characteristics of cerebral gray matter and deep white matter in patients with chronic cerebral artery severe stenosis or occlusion. Methods A retrospective study was conducted on 30 patients with chronic unilateral cerebral artery severe stenosis or occlusion from April 2014 to April 2018 in our hospital. Cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), time of peak time (TTP) and time to delay(TTD) of cerebral cortex gray matter and deep white matter in the blood supply area of the responsible artery (the affected side) and the contralateral hemisphere (the healthy side) were measured. Statistical analysis of the perfusion parameters of cerebral cortex gray matter and deep white matter in the affected side and contralateral side were performed using SPSS13.0 software package. T test was used for variance homogeneity, and t′ test was used for variance discrepancy, and P<0.05 was statistically significant. Results The average values of CBF and CBV of the ipsilateral and contralateral cerebral cortex were increased than those of ipsilateral and contralateral cerebral deep white matter respectively(P<0.01). MTT, TTP and TTD of the ipsilateral and contralateral cerebral cortex were decreased than that of ipsilateral and contralateral cerebral deep white matter (P<0.01); CBF of ipsilateral cerebral cortex and CBV of ipsilateral cerebral deep white matter were not different from those of the contralateral cerebral cortex and deep white matter respectively, but CBF of ipsilateral cerebral deep white matter is decreased than that of the contralateral deep white matter (P<0.01). CBV of ipsilateral cerebral cortex is increased than that of the contralateral cerebral cortex (P<0.01). MTT, TTP and TTD of ipsilateral cerebral cortex and deep white matter were increased than those of contralateral cerebral cortex and deep white matter respectively(P<0.01). Conclusion Deep cerebral white matter perfusion decreased more significantly than cortical gray matter in the supply region of chronic cerebral artery severe stenosis or occlusion. CT perfusion imaging can quantify the degree of chronic cerebral ischemia and can provide quantitative diagnostic information for clinical treatment and efficacy evaluation. Key words: Cerebral arteries; Tomography, X-ray computed; Stenosis; Occlusion

P1509The novel application of speckle tracking during dobutamine stress echo for assessment of coronary artery diseases

Abstract Background Major cause of death across the world is coronary artery disease. The choice of treatment strategy should be primarily based on the hemodynamic significance of coronary artery stenosis. Two-dimensional speckle tracking provides valuable information for regional wall motion abnormalities. The purpose of this study was to determine the diagnostic value of left ventricular longitudinal strain and torsion to diagnose coronary artery disease during dobutamine stress echocardiography. Purpose The purpose of this study was to evaluate the diagnostic value of speckle tracking imaging-derived myocardial deformation parameters at rest and during dobutamine stress to determine the hemodynamic significance of coronary artery stenosis in patients with moderate and high probability of CAD. Methods We studied 204 patients (mean age 54.2±9.8 years, 128 male and 76 female) with known or suspected coronary artery disease, excluding those with prior history of transmural infarction. All of them underwent dobutamine stress echo and coronary angiography within one month. Wall-motion score index, left ventricular global longitudinal strain and torsion were measured at rest and peak stress. Optimal cut-offs were derived from receiver operating characteristic curves for strain and torsion values. Additionally, the respective differences between rest and stress were also calculated. Results During dobutamine stress echocardiography we revealed mean left ventricular ejection fraction was 53±6.2%. Coronary angiography revealed significant stenotic lesions in 124 patients (60.7%). Values regarding sensitivity, and specificity for wall motion score index difference were 76% and 84% respectively (area under curve 0.84). Global longitudinal strain difference (median 0.6%) illustrated 83% sensitivity and 74% specificity for disease detection (area under curve 0.82, cut-off value ≤0.5%). The respective values for torsion difference (median 5.1°) were 84% and 79% (area under curve 0.80, cut-off value ≤5.9°). Combination of wall motion score index difference and torsion difference for disease detection showed 89% sensitivity and 77% specificity (area under curve 0.84). Conclusions Left ventricular strain and strain rate analyses during DSE can be used in the assessment of hemodynamic significance of coronary artery stenosis in patients with moderate and high risk for CAD. The implementation of speckle tracking during dobutamine stress echo could serve as an adjunct method for coronary artery disease assessment, providing quantitative diagnostic information.

Three-dimensional texture analysis of optical coherence tomography images of ovarian tissue

Ovarian cancer has the lowest survival rate among all gynecologic cancers due to predominantly late diagnosis. Optical coherence tomography (OCT) has been applied successfully to experimentally image the ovaries in vivo; however, a robust method for analysis is still required to provide quantitative diagnostic information. Recently, texture analysis has proved to be a useful tool for tissue characterization; unfortunately, existing work in the scope of OCT ovarian imaging is limited to only analyzing 2D sub-regions of the image data, discarding information encoded in the full image area, as well as in the depth dimension. Here we address these challenges by testing three implementations of texture analysis for the ability to classify tissue type. First, we test the traditional case of extracted 2D regions of interest; then we extend this to include the entire image area by segmenting the organ from the background. Finally, we conduct a full volumetric analysis of the image volume using 3D segmented data. For each case, we compute features based on the Grey-Level Co-occurence Matrix and also by introducing a new approach that evaluates the frequency distribution in the image by computing the energy density. We test these methods on a mouse model of ovarian cancer to differentiate between age, genotype, and treatment. The results show that the 3D application of texture analysis is most effective for differentiating tissue types, yielding an average classification accuracy of 78.6%. This is followed by the analysis in 2D with the segmented image volume, yielding an average accuracy of 71.5%. Both of these improve on the traditional approach of extracting square regions of interest, which yield an average classification accuracy of 67.7%. Thus, applying texture analysis in 3D with a fully segmented image volume is the most robust approach to quantitatively characterizing ovarian tissue.

Bioimpedance technology for detection of thoracic injury

Objective: Thoracic trauma is one of the most common and lethal types of injury, causing over a quarter of traumatic deaths. Severe thoracic injuries are often occult and difficult to diagnose in the field. There is a need for a point-of-care diagnostic device for severe thoracic injuries in the prehospital setting. Electrical bioimpedance (EBI) is non-invasive, portable, rapid and easy to use technology that can provide objective and quantitative diagnostic information for the prehospital environment. Here, we evaluated the performance of EBI to detect thoracic injuries. Approach: In this open study, EBI resistance (R), reactance (X) and phase angle (PA) of both sides of the thorax were measured at 50 kHz on patients suffering from thoracic injuries (n = 20). In parallel, a control group consisting of healthy subjects (n = 20) was recruited. A diagnostic mathematical algorithm, fed with input parameters derived from EBI data, was designed to differentiate patients from healthy controls. Main results: Ratios between the X and PA measurements of both sides of the thorax were significantly different (p < 0.05) between healthy volunteers and patients with left- and right-sided injuries. The diagnostic algorithm achieved a performance evaluated by leave-one-out cross-validation analysis and derived area under the receiver operating characteristic curve of 0.88. Significance: A diagnostic algorithm that accurately discriminates between patients suffering thoracic injuries and healthy subjects was designed using EBI technology. A larger, prospective and blinded study is thus warranted to validate the feasibility of EBI technology as a prehospital tool.

An Experimental Survey on the Effect of Using the CTS-6 Tool on the Diagnosis of Carpal Tunnel Syndrome by Hand Surgeons.

This controlled randomized experiment tested the research hypothesis that providing the CTS-6 quantitative diagnostic information to hand surgeons affects the diagnosis of carpal tunnel syndrome. Surgeon members of American Association for Hand Surgery participated in an online survey. Demographic and practice pattern information was collected. Few surgeons routinely use diagnostic questionnaires or algorithms. Each member was given four clinical scenarios. The respondents were randomized, The experimental group was given the same scenarios as the control group plus the quantitative results of the CTS-6 diagnostic tool. There were statistically significant differences between the groups in the diagnostic decisions. Using the CTS-6 quantitative diagnostic tool affected the diagnosis of carpal tunnel syndrome, especially for patients with the lowest number of findings associated with carpal tunnel syndrome. While accurate diagnostic decisions are dependent on the incorporation of all of the pertinent information gathered during the history and physical exams, the results of the CTS-6 may help the clinician focus their thinking and revise their diagnostic probabilities.

A tablet-interfaced high-resolution microendoscope with automated image interpretation for real-time evaluation of esophageal squamous cell neoplasia.

In recent years high-resolution microendoscopy (HRME) has shown potential to improve screening for esophageal squamous cell neoplasia. Furthering its utility in a clinical setting, especially in lower-resource settings, could be accomplished by reducing the size and cost of the system as well as incorporating the ability of real-time, objective feedback. This article describes a tablet-interfaced HRME with fully automated, real-time image analysis. The performance of the tablet-interfaced HRME was assessed by acquiring images from the oral mucosa in a normal volunteer. An automated, real-time analysis algorithm was developed and evaluated using training, test, and validation images from a previous invivo study of 177 patients referred for screening or surveillance endoscopy in China. The algorithm was then implemented in a tablet HRME that was used to obtain and analyze images from esophageal tissue in 3 patients. Images were displayed alongside the probability that the imaged region was neoplastic. The tablet-interfaced HRME demonstrated comparable imaging performance at a lower cost compared with first-generation laptop-interfaced HRME systems. In a post-hoc quantitative analysis, the algorithm identified neoplasia with a sensitivity and specificity of 95% and 91%, respectively, in the validation set compared with 84% and 95% achieved in the original study. The tablet-based HRME is a low-cost tool that provides quantitative diagnostic information to the endoscopist in real time. This could be especially beneficial in lower-resource settings for operators with less experience interpreting HRME images.

Two-dimensional speckle tracking for the assessment of coronary artery disease during dobutamine stress echo: clinical tool or merely research method.

BackgroundTwo-dimensional speckle tracking provides valuable information for regional wall motion abnormalities. The purpose of this study was to determine the diagnostic value of left ventricular longitudinal strain and torsion to diagnose coronary artery disease during dobutamine stress echocardiography.MethodsWe studied 100 patients (mean age 60.8 ± 10.7 years, 72 male) with known or suspected coronary artery disease, excluding those with prior history of transmural infraction. All of them underwent dobutamine stress echo and coronary angiography within one month. Wall-motion score index, left ventricular global longitudinal strain and torsion were measured at rest and peak stress. Additionally, the respective differences between rest and stress were also calculated. Optimal cut-offs were derived from receiver operating characteristic curves for strain and torsion values.ResultsMean left ventricular ejection fraction was 55 ± 5.4 %. Coronary angiography revealed significant lesions in 67 patients. Values regarding sensitivity, and specificity for wall motion score index difference were 78 % and 88 % respectively (area under curve 0.84). Global longitudinal strain difference (median 0.5 %) illustrated 81 % sensitivity and 72 % specificity for disease detection (area under curve 0.80, cut-off value ≤0 %). The respective values for torsion difference (median 4.7°) were 81 % and 82 % (area under curve 0.76, cut-off value ≤6.5°). Combination of wall motion score index difference and torsion difference for disease detection showed 91 % sensitivity and 79 % specificity (area under curve 0.85).ConclusionsThe implementation of speckle tracking during dobutamine stress echo could serve as an adjunct method for coronary artery disease assessment, providing quantitative diagnostic information.

Nonlinear propagation effects on measurement of backscatter coefficient of tissue-mimicking materials

Measurement of the ultrasonic backscatter coefficient (BSC) holds great promise in providing quantitative diagnostic information on various diseases. Many clinical studies utilize the reference phantom method. In this method, the measured BSC is the ratio of the power spectrum of the scattered sound from the patient to the power spectrum from the reference phantom multiplied by the known BSC of the reference and an attenuation correction factor. In these studies, nonlinear propagation has been ignored. Nonlinear propagation causes changes in the power spectrum as incident energy is converted to harmonics and the acoustic signal undergoes nonlinear attenuation. This study characterized the effects of nonlinear propagation on reference phantom measurements of BSC from four tissue-mimicking samples in the frequency range from 2 to 20 MHz and incident pressure from 1 to 10 MPa (measured in water) using single element focused transducers. Samples consisted of glass microspheres suspended in a mixture of agar and concentrated milk. The resulting BSC varied by up to a factor of 30 depending on the incident pressure. Substantial changes in the overall shape of the BSC vs frequency were also observed. New methods of measurement of BSC that account for nonlinear propagation are explored.

Application of Selected Reaction Monitoring for Multiplex Quantification of Clinically Validated Biomarkers in Formalin-Fixed, Paraffin-Embedded Tumor Tissue

One of the critical gaps in the clinical diagnostic space is the lack of quantitative proteomic methods for use on formalin-fixed, paraffin-embedded (FFPE) tissue. Herein, we describe the development of a quantitative, multiplexed, mass spectrometry-based selected reaction monitoring (SRM) assay for four therapeutically important targets: epidermal growth factor receptor, human EGF receptor (HER)-2, HER3, and insulin-like growth factor-1 receptor. These assays were developed using the Liquid Tissue-SRM technology platform, in which FFPE tumor tissues were microdissected, completely solubilized, and then subjected to multiplexed quantitation by SRM mass spectrometry. The assays were preclinically validated by comparing Liquid Tissue-SRM quantitation of FFPE cell lines with enzyme-linked immunosorbent assay/electrochemiluminescence quantitation of fresh cells (R(2) > 0.95). Clinical performance was assessed on two cohorts of breast cancer tissue: one cohort of 10 samples with a wide range of HER2 expression and a second cohort of 19 HER2 IHC 3+ tissues. These clinical data demonstrate the feasibility of quantitative, multiplexed clinical analysis of proteomic markers in FFPE tissue. Our findings represent a significant advancement in cancer tissue analysis because multiplexed, quantitative analysis of protein targets in FFPE tumor tissue can be tailored to specific oncological indications to provide the following: i) complementary support for anatomical pathological diagnoses, ii) patient stratification to optimize treatment outcomes and identify drug resistance, and iii) support for the clinical development of novel therapies.

A Portable, Pressure Driven, Room Temperature Nucleic Acid Extraction and Storage System for Point of Care Molecular Diagnostics.

Many new and exciting portable HIV viral load testing technologies are emerging for use in global medicine. While the potential to provide fast, isothermal, and quantitative molecular diagnostic information to clinicians in the field will soon be a reality, many of these technologies lack a robust front end for sample clean up and nucleic acid preparation. Such a technology would enable many different downstream molecular assays. Here, we present a portable system for centrifuge-free room temperature nucleic acid extraction from small volumes of whole blood (70 µL), using only thermally stable reagents compatible with storage and transport in low resource settings. Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) analysis of simulated samples demonstrate a lower limit of detection of 1000 copies/ml, with the ability to detect differences in viral load across four orders of magnitude. The system can also be used to store extracted RNA on detachable cartridges for up to one week at ambient temperature, and can be operated using only hand generated air pressure.

Local property characterization of prostate glands using inhomogeneous modeling based on tumor volume and location analysis

Mechanical property characterization of prostate tumors can enhance the results obtained by palpation by providing quantitative and precise diagnostic information to surgeons. The multi-focal characteristics of prostate tumors cause inhomogeneity and local property variance in the prostate glands, which is one reason for inaccurate property characterizations of the tumors. Therefore, biomechanical models should include inhomogeneity and local property variance by taking into consideration the anatomical information (location and volume) of the tumors. We developed six inhomogeneous local prostate models using the finite element method, which takes into account the location and volume information of prostate tumors. The models were divided into six different sections: lateral apex, lateral mid, lateral base, medial apex, medial mid and medial base tumors. Information on the location and volume of prostate tumors was obtained using pathological analysis. The mechanical properties of prostate tumors were estimated using the developed model simulation and the ex vivo indentation experiment results from the human resected prostates. The results showed that the mean elastic moduli of the normal and tumoral regions were 14.7 and 41.6 kPa, respectively. Our models provided more reliable estimates of the elastic moduli than the conventionally used Hertz-Sneddon model, and the results from our model were more closely correlated with previous studies due to the inclusion of the anatomical information via inhomogeneous modeling. These six local models provide baseline property criteria for the diagnosis and localization of prostate tumors using the optimized elastic moduli of normal prostate tissues.