Conventional Sequences Research Articles

Fast cardiac magnetic resonance protocol. Feasibility of accelerated compressed sensing cine sequences in clinical practice

ObjectiveTo demonstrate the feasibility of cardiac magnetic resonance (CMR) cine sequences with compressed-sensing (CS) acceleration in the assessment of ventricular anatomy, volume, and function; and to present a fast CRM protocol that improves scan efficiency. MethodsProspective study of consecutive patients with indication for CMR who underwent CS short-axis (SA) cine imaging compared with conventional SA cine imaging. We analysed ejection fraction (EF), end-diastolic volume (EDV), stroke volume (SV), and myocardial thickness. Two blinded independent observers performed the reading. Inter- and intraobserver agreement was calculated for all the measurements. Image quality of conventional and CS cine sequences was also assessed. ResultsA total of 50 patients were included, 22 women (44%) with a mean age of 57.3 ± 13.2 years. Mean left ventricular EF was 59.1% ± 10.4% with the reference steady-state free precession sequences, versus 58.7% ± 10.6% with CS; and right ventricular EF with conventional imaging was 59.3% ± 5.7%, versus 59.5% ± 6.1% with CS. Mean left ventricular EDV for conventional sequences and CS were 166.8 and 165.1 ml respectively; left ventricular SV was 94.5 versus 92.6 ml; right ventricular EDV was 159.3 versus 156.4 ml; and right ventricular SV was 93.6 versus 91.2 ml, respectively. Excellent intra and interobserver correlations were obtained for all parameters (Intraclass correlation coefficient between 0.932 and 0.99; CI: 95%). There were also no significant differences in ventricular thickness (12.9 ± 2.9 mm vs 12.7 ± 3.1 mm) (p < .001). The mean time of CS SA was <40 sec versus 6–8 min for the conventional SA. The mean duration of the complete study was 15 ± 3 min. ConclusionsCine CS sequences are feasible for assessing biventricular function, volume, and anatomy, enabling fast CMR protocols.

Evaluation of the role of diffusion-weighted imaging in various pancreatic pathologies

Background: Diffusion-weighted imaging (DWI) can confidently characterize the nature of a lesion. “Apparent diffusion coefficient” (ADC) has a role in evaluating malignant lesions of the pancreas when conventional sequences appear normal. Aims and Objectives: The aim of the study was to determine the role of DWI and ADC to differentiate benign from malignant pancreatic lesions. Materials and Methods: An observational study was carried out on 75 participants with a suggestion of pancreatic pathologies at a tertiary care institute. Twenty-five participants, who had normal parenchyma of the pancreas, were taken as controls. Magnetic resonance imaging protocol was done, including DWI and ADC. Data analysis was done using coGuide software. ADC was the primary outcome of interest. Results: Out of the 75 cases, 76.9 % (n=60) were males. 15.4 % (n=9) of pathologies were malignant. A significant decrease of ADC values in subjects with acute diffuse pancreatitis (1.12×10-3), acute on chronic pancreatitis (1.14×10-3), chronic pancreatitis (1.32×10-3) as well as adenocarcinoma pancreas (0.92×10-3) was seen in comparison to the controls (1.41×10-3). ADC values for acute pancreatitis, chronic pancreatitis, and acute on chronic pancreatitis were significantly higher than malignancy. Conclusion: DWI and ADC is a useful tools complementing conventional MR imaging and other imaging modalities in characterizing pancreatic pathologies. Mean ADC values of various pancreatic diseases can be determined without major overlap and a reasonable cutoff value can be obtained for differentiating benign and malignant lesions.

Ultrashort echo time pulse sequences for visualization of deep peripheral fasciae and epimysium in porcine models with histologic correlations.

The deep peripheral fascia and epimysium are vital for muscle and tendon support, but their tight proton composition results in hypointense signals in conventional spin echo sequences. Ultrashort echo time (UTE) magnetic resonance imaging (MRI), using microsecond TE values, may visualize these structures. The purpose of this study was to evaluate whether UTE pulse sequence with a three-dimensional cone trajectory (3D UTE), with or without fat suppression (FS), can be used to visualize the fascia and epimysium using porcine lower legs as an example. The anterior soft tissues of porcine lower legs were dissected and partially separated into distinct layers to expose the deep peripheral fascia, epimysium, and muscle. Axial 3D UTE and 3D UTE FS imaging using dual-echo acquisition and echo subtraction were performed both before and after dissection. Prior to dissection, the thickness, signal-to-noise ratios (SNRs), and contrast-to-noise ratios (CNRs) of structures believed to be deep peripheral fascia and epimysium were measured in both 3D UTE and 3D UTE FS. Post-dissection images were also analyzed to measure the SNRs and CNRs for the deep peripheral fascia and epimysium. Histological evaluations were carried out to verify the identities of the deep peripheral fascia and epimysium, as well as their thickness, and these measurements were compared to imaging findings. In pre-dissection images obtained with 3D UTE and 3D UTE FS, both the deep peripheral fascia and epimysium exhibited high signal intensity. In the subtraction images, the mean thickness of the deep fascia was 0.87 mm, and that of the epimysium was 0.80 mm when imaged with 3D UTE. This is compared to measurements of 0.77 and 0.22 mm in 3D UTE FS, respectively. Histological analyses confirmed the thickness of the deep peripheral fascia and epimysium as 0.65 and 0.14 mm, respectively. In the post-dissection images, the deep fascia continued to display high signal intensity when compared with adjacent soft tissues, consistent with the histological findings. Meanwhile, the epimysium showed very low CNRs. 3D UTE and 3D UTE FS can be used to visualize the deep peripheral fascia with high signal intensity and contrast but are insufficient to show signal intensity in the epimysium.

Assessment of ultrashort echo time (UTE) T2* mapping at 3T for the whole knee: repeatability, the effects of fat suppression, and knee position.

Knee tissues such as tendon, ligament and meniscus have short T2* relaxation times and tend to show little to no signal in conventional magnetic resonance acquisitions. An ultrashort echo time (UTE) technique offers a unique tool to probe fast-decaying signals in these tissues. Clinically relevant factors should be evaluated to quantify the sensitivity needed to distinguish diseased from control tissues. Therefore, the objectives of this study were to (I) quantify the repeatability of UTE-T2* relaxation time values, and (II) evaluate the effects of fat suppression and (III) knee positioning on UTE-T2* relaxation time quantification. A dual-echo, three-dimensional center-out radially sampling UTE and conventional gradient echo sequences were utilized to image gadolinium phantoms, one ex-vivo specimen, and five in-vivo subjects on a clinical 3T scanner. Scan-rescan images from the phantom and in-vivo experiments were used to evaluate the repeatability of T2* relaxation time values. Fat suppressed and non-suppressed images were acquired for phantoms and the ex-vivo specimen to evaluate the effect of fat suppression on T2* relaxation time quantifications. The effect of knee positioning was evaluated by imaging in-vivo subjects in extended and flexed positions within the knee coil and comparing T2* relaxation times quantified from tissues in each position. Phantom and in-vivo measurements demonstrated repeatable T2* mapping, where the percent difference between T2* relaxation time quantified from scan-rescan images was less than 8% for the phantom and knee tissues. The coefficient of variation across fat suppressed and non-suppressed images was less than 5% for the phantoms and ex-vivo knee tissues, showing that fat suppression had a minimal effect on T2* relaxation time quantification. Knee position introduced variability to T2* quantification of the anterior cruciate ligament, posterior cruciate ligament, and patellar tendon, with percent differences exceeding 20%, but the meniscus showed a percent difference less than 10%. The 3D radial UTE sequence presented in this study could potentially be used to detect clinically relevant changes in mean T2* relaxation time, however, reproducibility of these values is impacted by knee position consistency between scans.

Radiogenomics for predicting microsatellite instability status and PD-L1 expression with machine learning in endometrial cancers: A multicenter study

PurposeTo evaluate the effectiveness of machine learning model based on magnetic resonance imaging (MRI) in identifying microsatellite instability (MSI) status and PD-L1 expression in endometrial cancer (EC). MethodsThis retrospective study included 82 EC patients from 2 independent centers. Radiomics features from the intratumoral and peritumoral regions, obtained from four conventional MRI sequences (T2-weighted images; contrast-enhanced T1-weighted images; diffusion-weighted images; apparent diffusion coefficient), were combined with clinicopathologic characteristics to develop machine learning model for predicting MSI status and PD-L1 expression. 60 patients from center 1 were used as the training set for model construction, while 22 patients from center 2 were used as an external validation set for model evaluation. ResultsFor predicting MSI status, the clinicopathologic model, radscore model, and combination model achieved area under the curves (AUCs) of 0.728, 0.833, and 0.889 in the training set, respectively, and 0.595, 0.790, and 0.848 in the validation set, respectively. For predicting PD-L1 expression, the clinicopathologic model, radscore model, and combination model achieved AUCs of 0.648, 0.814, and 0.834 in the training set, respectively, and 0.660, 0.708, and 0.764 in the validation set, respectively. Calibration curve analysis and decision curve analysis demonstrated good calibration and clinical utility of the combination model. ConclusionThe machine learning model incorporating MRI-based radiomics features and clinicopathologic characteristics could be a potential tool for predicting MSI status and PD-L1 expression in EC. This approach may contribute to precision medicine for EC patients.

Biological underpinnings of radiomic magnetic resonance imaging phenotypes for risk stratification in IDH wild-type glioblastoma

BackgroundTo develop and validate a conventional MRI-based radiomic model for predicting prognosis in patients with IDH wild-type glioblastoma (GBM) and reveal the biological underpinning of the radiomic phenotypes.MethodsA total of 801 adult patients (training set, N = 471; internal validation set, N = 239; external validation set, N = 91) diagnosed with IDH wild-type GBM were included. A 20-feature radiomic risk score (Radscore) was built for overall survival (OS) prediction by univariate prognostic analysis and least absolute shrinkage and selection operator (LASSO) Cox regression in the training set. GSEA and WGCNA were applied to identify the intersectional pathways underlying the prognostic radiomic features in a radiogenomic analysis set with paired MRI and RNA-seq data (N = 132). The biological meaning of the conventional MRI sequences was revealed using a Mantel test.ResultsRadscore was demonstrated to be an independent prognostic factor (P < 0.001). Incorporating the Radscore into a clinical model resulted in a radiomic-clinical nomogram predicting survival better than either the Radscore model or the clinical model alone, with better calibration and classification accuracy (a total net reclassification improvement of 0.403, P < 0.001). Three pathway categories (proliferation, DNA damage response, and immune response) were significantly correlated with the prognostic radiomic phenotypes.ConclusionOur findings indicated that the prognostic radiomic phenotypes derived from conventional MRI are driven by distinct pathways involved in proliferation, DNA damage response, and immunity of IDH wild-type GBM.

The Effects of Free Breathing on Cerebral Venous Flow: A Real-Time Phase Contrast MRI Study in Healthy Adults.

Quantifying the effects of free breathing on cerebral venous flow is crucial for understanding cerebral circulation mechanisms and clinical applications. Unlike conventional cine phase-contrast MRI sequences (CINE-PC), real-time phase-contrast MRI sequences (RT-PC) can provide a continuous beat-to-beat flow signal that makes it possible to quantify the effect of breathing on cerebral venous flow. In this study, we examined 28 healthy human participants, comprising of 14 males and 14 females. Blood flows in the right/left internal jugular veins in the extracranial plane and the superior sagittal sinus (SSS) and straight sinus in the intercranial plane were quantified using CINE-PC and RT-PC. The first objective of this study was to determine the accuracy of RT-PC in quantifying cerebral venous flow, relative to CINE-PC. The second, and main objective, was to quantify the effect of free breathing on cerebral venous flow, using a time-domain multiparameter analysis method. Our results showed that RT-PC can accurately quantify cerebral venous flow with a 2 × 2 mm2 spatial resolution and 75 ms/image time resolution. The mean flow rate, amplitude, stroke volume, and cardiac period of cerebral veins were significantly higher from the mid-end phase of expiration to the mid-end phase of inspiration. Breathing affected the mean flow rates in the jugular veins more than those in the SSS and straight sinus. Furthermore, the effects of free breathing on the flow rate of the left and right jugular veins were not synchronous. These new findings provide a useful reference for better understanding the mechanisms of cerebral circulation.

Abstract 17723: Non-Contrast Cardiac Magnetic Resonance BOOST Whole Heart Acquisition to Evaluate Coronaries in Children and Young Adults

Introduction: Cardiac magnetic resonance (CMR) coronary evaluation remains challenging in teenagers and young adults using conventional respiratory navigation strategies due to irregular respiratory patterns. Motion correction strategies have shown promise in improving efficiency and quality. We sought to evaluate a non-contrast 3D whole-heart sequence with bright-blood (BB) and dark-blood (DB) phase sensitive inversion recovery (BOOST) using image-based navigation (iNAV) and a variable-density cartesian spiral profile order trajectory (VD-CASPR). Hypothesis: BOOST acquisitions improves delineation of coronary origins and proximal courses. Methods: Pts undergoing clinically indicated CMRs were prospectively enrolled and scanned at 1.5T (AVANTO FIT, Siemens) using 2 different imaging methods: 1) BOOST research sequence employing either T2 or magnetization transfer preparation at 1.0-1.4 mm isotropic resolution. When clinically indicated, 2) a standard navigated inversion recovery gradient echo sequence (IR-FLASH) acquired after gadolinium or ferumoxytol infusion. Both coronary imaging methods were rated on a 1-4 scale: 1=non-diagnostic, 2=coronary origins with significant image degradation, 3=mild image degradation, and 4=sharp delineation of the proximal coronaries. A composite BOOST score (highest score between BB and DB images) was compared to IR-FLASH. Group comparisons used a paired t-test (two-tailed, p&lt;0.05). Results: 18 pts, mean age 18.8 years (range=10-31) underwent BOOST imaging. 15 had an IR-FLASH for comparison. BOOST acquisition times were 7-12 minutes. Three pts had coronary anomalies (2 with right coronary from the left sinus, 1 single coronary). Coronary origins were delineated on all BOOST exams with a mean score=3.6 for BB BOOST and 2.9 for DB compared to 3.1 for the IR-FLASH, neither of which was significantly different. The composite BOOST mean score was 3.8, which was significantly higher than IR-FLASH. Conclusions: In our series in children and young adults, contrast-free BOOST imaging delineated coronary origins in all pts, even in challenging cases of anomalous origins. When utilizing both BB and DB BOOST images, image quality exceeded that of a conventional post-contrast IR-FLASH sequence.

DTI-MR fingerprinting for rapid high-resolution whole-brain T1 , T2 , proton density, ADC, and fractional anisotropy mapping.

This study aims to develop a high-efficiency and high-resolution 3D imaging approach for simultaneous mapping of multiple key tissue parameters for routine brain imaging, including T1 , T2 , proton density (PD), ADC, and fractional anisotropy (FA). The proposed method is intended for pushing routine clinical brain imaging from weighted imaging to quantitative imaging and can also be particularly useful for diffusion-relaxometry studies, which typically suffer from lengthy acquisition time. To address challenges associated with diffusion weighting, such as shot-to-shot phase variation and low SNR, we integrated several innovative data acquisition and reconstruction techniques. Specifically, we used M1-compensated diffusion gradients, cardiac gating, and navigators to mitigate phase variations caused by cardiac motion. We also introduced a data-driven pre-pulse gradient to cancel out eddy currents induced by diffusion gradients. Additionally, to enhance image quality within a limited acquisition time, we proposed a data-sharing joint reconstruction approach coupled with a corresponding sequence design. The phantom and in vivo studies indicated that the T1 and T2 values measured by the proposed method are consistent with a conventional MR fingerprinting sequence and the diffusion results (including diffusivity, ADC, and FA) are consistent with the spin-echo EPI DWI sequence. The proposed method can achieve whole-brain T1 , T2 , diffusivity, ADC, and FA maps at 1-mm isotropic resolution within 10 min, providing a powerful tool for investigating the microstructural properties of brain tissue, with potential applications in clinical and research settings.

Value of Non-Contrast-Enhanced Vessel Wall MR Imaging in Assessing Vascular Invasion of Retroperitoneal Tumors.

Due to their location and growth patterns, retroperitoneal tumors often involve the surrounding blood vessels. Clinical decisions on a proper treatment depend on the information on this condition. Evaluation of blood vessels using non-contrast-enhanced vessel wall MRI may provide noninvasive assessment of the extent of tumor invasion to assist clinical decision-making. To investigate the performance and potential of non-contrast-enhanced vessel wall MRI in evaluating the degree of vessel wall invasion of retroperitoneal tumors. Prospective. Thirty-seven participants (mean age: 60.59 ± 11.77 years, 59% male) with retroperitoneal tumors close to vessels based on their diagnostic computer tomography. 3 T; vessel wall MRI sequences: two-dimensional T2-weighted MultiVane XD turbo spin-echo (2D-T2-MVXD-TSE) and three-dimensional T1-weighted motion sensitized driven equilibrium fat suppression turbo spin-echo (3D-T1-MSDE-TSE) sequences; conventional MRI sequences: T2-weighted fat suppression turbo spin-echo (T2-FS-TSE), T2-weighted turbo spin-echo (T2-TSE), modified Dixon T1-weighted fast field echo (T1-mDixon-FFE), and diffusion-weighted echo planar imaging (DWI-EPI) sequences. All patients underwent preoperative imaging using both non-contrast conventional and vessel wall MRI sequences. Images obtained from conventional and vessel wall MRI sequences were evaluated independently by three junior radiologists (3 and 2 years of experience in reading MRI) and reviewed by one senior radiologist (25 years of experience in reading MRI) to assess the degree of vessel wall invasion. MRI were validated results from the clinical standard diagnosis based on surgical confirmation or histopathological reports. Interobserver agreement was determined based on the reports from three readers with similar years of experiences. Intraobserver variability was assessed based on categorizing and recategorizing the vessels of 37 patients 1 month apart. Intra-class correlation efficient (ICC), Chi-square test, McNemar test, area under the receiver-operating characteristic curve (AUC), Delong test, P < 0.05 was considered significant. The accuracy of vessel wall MRI (91.96%, 95% CI: 85.43-95.71; 103 of 112) in detecting the degree of vessel wall invasion was significantly higher than that of conventional MRI (75%, 95% CI: 66.24-82.10; 84 of 112). The interobserver variability or reproducibility in categorization of the degree of vascular wall invasion was good in evaluating images from conventional and vessel wall MRI sequences (ICC = 0.821, 95% CI: 0.765-0.867 and ICC = 0.881, 95% CI: 0.842-0.913, respectively). Diagnosis of vessel wall invasion of retroperitoneal tumors and assessment of its severity can be improved by using non-contrast-enhanced vessel wall MRI. 1 TECHNICAL EFFICACY: Stage 3.

Feature-Tracking Strain Parameters Differ Between Highly Accelerated and Conventional Acquisitions: A Multisoftware Assessment.

Cardiac magnetic resonance imaging protocols have been adapted to fit the needs for faster, more efficient acquisitions, resulting in the development of highly accelerated, compressed sensing-based (CS) sequences. The aim of this study was to evaluate intersoftware and interacquisition differences for postprocessing software applied to both CS and conventional cine sequences. A total of 106 individuals (66 healthy volunteers, 40 patients with dilated cardiomyopathy, 51% female, 38±17y) underwent cardiac magnetic resonance at 3T with retrospectively gated conventional cine and CS sequences. Postprocessing was performed using 2 commercially available software solutions and 1 research prototype from 3 different developers. The agreement of clinical and feature-tracking strain parameters between software solutions and acquisition types was assessed by Bland-Altmann analyses and intraclass correlation coefficients. Differences between softwares and acquisitions were assessed using Kruskal-Wallis analysis of variances. In addition, receiver operating characteristic curve-derived cutoffs were used to evaluate whether sequence-specific cutoffs influence disease classification. There were significant intersoftware ( P <0.002 for all except LV end-diastolic volume per body surface area) and interacquisition differences ( P <0.02 for all except end-diastolic volume per body surface area from Neosoft, left ventricular mass per body surface area from cvi42 and TrufiStrain and global circumferential strain from Neosoft). However, the intraclass correlation coefficients between acquisitions were strong-to-excellent for all parameters (all ≥0.81). In comparing individual softwares to a pooled mean, Bland-Altmann analyses revealed smaller magnitudes of bias for cine acquisition than for CS acquisition. In addition, the application of conventional cutoffs to CS measurements did not result in the false reclassification of patients. Significantly lower magnitudes of strain and volumetric parameters were observed in retrospectively gated CS acquisitions, despite strong-to-excellent agreement amongst software solutions and acquisition types. It remains important to be aware of the acquisition type in the context of follow-up examinations, where different cutoffs might lead to misclassifications.

Fine wine recognition and appreciation: It is time to change the paradigm of wine tasting

Wine quality maybe understood under two perspectives: (a) commercial quality, intended to satisfy overall consumers, and (b) fine wine quality, aimed at achieving a product with aesthetic value. The current food sensory techniques (e.g. Descriptive Analysis) have been successfully applied to develop wines accepted worldwide and characterized by pleasant sweetish flavours and smooth mouthfeel. On the contrary, these techniques are not suited to characterize fine wines given their dependence on sensory properties with aesthetic value. The conventional tasting approaches follow the sequence of vision, smell (orthonasal), taste and mouthfeel, ending by an overall evaluation. The sensory descriptors tend to be analytic (e.g. different aromas and tastes) or synthetic (e.g. body, structure) and the quality judgement is left for the final step. Some synthetic attributes may have an aesthetic significance (e.g. complexity, harmony, depth) and are more valued when the analytic or synthetic descriptors are highly praised (e.g. oakiness, silkiness, body, minerality). Consequently, these highly praised attributes are regarded as surrogates of fine wine quality. However, commercial wines are frequently judged of higher quality than fine wines irrespective of the taster expertise. We argue that the conventional sensory analysis sequence makes the overall evaluation secondary in relation to the previous analytical steps blurring the assessment of wine’s aesthetic properties. Probably due to top-down processing, the initial evaluation of colour or flavours governs the final overall quality evaluation that may be inconsistently rated. Then, to promote the recognition of fine wines, tasting should begin by first acknowledging the aesthetic properties and only proceed to the analytical steps if necessary. A tasting method is proposed to consumer educational programs where emotional responses are used to explain the differences between commercial and fine wine styles. Furthermore, cultural aspects should be included to appreciate the wholeness of wine. Hopefully, this holistic perspective would turn wine appreciation more approachable and facilitate the recognition of fine wines among consumers, increasing their appreciation and enjoyment.

Separation of Ternary System 1,2-Ethanediol + 1,3-Propanediol + 1,4-Butanediol by Liquid-Only Transfer Dividing Wall Column

This study focuses on separating a mixture consisting of 1,2-ethanediol (1,2-ED), 1,3-propanediol (1,3-PD), and 1,4-butanediol (1,4-BD). Vapor–liquid equilibrium (VLE) data for 1,2-ED + 1,4-BD and 1,3-PD + 1,4-BD are determined at 101.3 kPa using a modified Rose equilibrium still. The consistency of the VLE data is checked with both Redlich–Kister and Fredenslund tests. The VLE data are fitted by the Wilson, NRTL, and UNIQUAC activity coefficient models. All three models can effectively correlate the VLE data. Then, the separation of the mixture is designed with the NRTL model and its correlated binary interaction parameters. A liquid-only transfer dividing wall column (LDWC) is investigated on the basis of a direct conventional distillation sequence (DCDS). For a fair comparison, both DCDS and LDWC are optimized to minimize total annual cost using sequential iterative optimization procedures. After optimization, LDWC exhibits a 16.87% reduction in total annual cost, while cooling and heating utility consumptions are reduced by 28.40% and 19.24% compared to DCDS.

Three-dimensional ultrashort echo time magnetic resonance imaging in pediatric patients with pneumonia: a comparative study

BackgroundUTE has been used to depict lung parenchyma. However, the insufficient discussion of its performance in pediatric pneumonia compared with conventional sequences is a gap in the existing literature. The objective of this study was to compare the diagnostic value of 3D-UTE with that of 3D T1-GRE and T2-FSE sequences in young children diagnosed with pneumonia.MethodsSeventy-seven eligible pediatric patients diagnosed with pneumonia at our hospital, ranging in age from one day to thirty-five months, were enrolled in this study from March 2021 to August 2021. All patients underwent imaging using a 3 T pediatric MR scanner, which included three sequences: 3D-UTE, 3D-T1 GRE, and T2-FSE. Subjective analyses were performed by two experienced pediatric radiologists based on a 5-point scale according to six pathological findings (patchy shadows/ground-glass opacity (GGO), consolidation, nodule, bulla/cyst, linear opacity, and pleural effusion/thickening). Additionally, they assessed image quality, including the presence of artifacts, and evaluated the lung parenchyma. Interrater agreement was assessed using intraclass correlation coefficients (ICCs). Differences among the three sequences were evaluated using the Wilcoxon signed-rank test.ResultsThe visualization of pathologies in most parameters (patchy shadows/GGO, consolidation, nodule, and bulla/cyst) was superior with UTE compared to T2-FSE and T1 GRE. The visualization scores for linear opacity were similar between UTE and T2-FSE, and both were better than T1-GRE. In the case of pleural effusion/thickening, T2-FSE outperformed the other sequences. However, statistically significant differences between UTE and other sequences were only observed for patchy shadows/GGO and consolidation. The overall image quality was superior or at least comparable with UTE compared to T2-FSE and T1-GRE. Interobserver agreements for all visual assessments were significant and rated “substantial” or “excellent.”ConclusionsIn conclusion, UTE MRI is a useful and promising method for evaluating pediatric pneumonia, as it provided better or similar visualization of most imaging findings compared with T2-FSE and T1-GRE. We suggest that the UTE MRI is well-suited for pediatric population, especially in younger children with pneumonia who require longitudinal and repeated imaging for clinical care or research and are susceptible to ionizing radiation.

Protocolo rápido de resonancia magnética cardiaca. Viabilidad de las secuencias cine aceleradas con compressed sensing en la práctica clínica

ObjectiveTo demonstrate the feasibility of cardiac magnetic resonance (CMR) cine sequences with compressed-sensing (CS) acceleration in the assessment of ventricular anatomy, volume, and function; and to present a fast CRM protocol that improves scan efficiency. MethodsProspective study of consecutive patients with indication for CMR who underwent CS short-axis (SA) cine imaging compared with conventional SA cine imaging. We analysed ejection fraction (EF), end-diastolic volume (EDV), stroke volume (SV), and myocardial thickness. Two blinded independent observers performed the reading. Inter- and intraobserver agreement was calculated for all the measurements. Image quality of conventional and CS cine sequences was also assessed. ResultsA total of 50 patients were included, 22 women (44%) with a mean age of 57.3±13.2 years. Mean left ventricular EF was 59.1%±10.4% with the reference steady-state free precession sequences, versus 58.7%±10.6% with CS; and right ventricular EF with conventional imaging was 59.3%±5.7%, versus 59.5%±6.1% with CS. Mean left ventricular EDV for conventional sequences and CS were 166.8 and 165.1ml respectively; left ventricular SV was 94.5 versus 92.6ml; right ventricular EDV was 159.3 versus 156.4 ml; and right ventricular SV was 93.6 versus 91.2ml, respectively. Excellent intra and interobserver correlations were obtained for all parameters (Intraclass correlation coefficient between 0.932 and 0.99; CI: 95%). There were also no significant differences in ventricular thickness (12.9±2.9mm vs. 12.7±3.1mm) (p<.001). The mean time of CS SA was <40 sec versus 6-8 min for the conventional SA. The mean duration of the complete study was 15±3 min. ConclusionsCine CS sequences are feasible for assessing biventricular function, volume, and anatomy, enabling fast CMR protocols.

Non-invasive monitoring of neoadjuvant radiation therapy response in soft tissue sarcomas by multiparametric MRI and quantification of circulating tumor DNA-A study protocol.

Wide resection remains the cornerstone of localized soft-tissue sarcomas (STS) treatment. Neoadjuvant radiation therapy (NRT) may decrease the risk of local recurrences; however, its effectiveness for different histological STS subtypes has not been systematically investigated. The proposed prospective study evaluates the NRT response in STS using liquid biopsies and the correlation of multiparametric magnetic resonance imaging (mpMRI) with histopathology and immunohistochemistry. Patients with localized high-grade STS, who qualify for NRT, are included in this study. Quantification of circulating tumor DNA (ctDNA) in patient blood samples is performed by targeted next-generation sequencing. Soft-tissue sarcoma subtype-specific panel sequencing in combination with patient-specific exome sequencing allows the detection of individual structural variants and point mutations. Circulating free DNA is isolated from peritherapeutically collected patient plasma samples and ctDNA quantified therein. Identification of breakpoints is carried out using FACTERA. Bioinformatic analysis is performed using samtools, picard, fgbio, and the MIRACUM Pipeline. Combination of conventional MRI sequences with diffusion-weighted imaging, intravoxel-incoherent motion, and dynamic contrast enhancement. Multiparametric MRI is performed before, during, and after NRT. We aim to correlate mpMRI data with the resected specimen's macroscopical, histological, and immunohistochemical findings. Preliminary data support the notion that quantification of ctDNA in combination with tumor mass characterization through co-registration of mpMRI and histopathology can predict NRT response of STS. The methods presented in this prospective study are necessary to assess therapy response in heterogeneous tumors and lay the foundation of future patient- and tumor-specific therapy concepts. These methods can be applied to various tumor entities. Thus, the participation and support of a wider group of oncologic surgeons are needed to validate these findings on a larger patient cohort.

PLM-ARG: antibiotic resistance gene identification using a pretrained protein language model.

Antibiotic resistance presents a formidable global challenge to public health and the environment. While considerable endeavors have been dedicated to identify antibiotic resistance genes (ARGs) for assessing the threat of antibiotic resistance, recent extensive investigations using metagenomic and metatranscriptomic approaches have unveiled a noteworthy concern. A significant fraction of proteins defies annotation through conventional sequence similarity-based methods, an issue that extends to ARGs, potentially leading to their under-recognition due to dissimilarities at the sequence level. Herein, we proposed an Artificial Intelligence-powered ARG identification framework using a pretrained large protein language model, enabling ARG identification and resistance category classification simultaneously. The proposed PLM-ARG was developed based on the most comprehensive ARG and related resistance category information (>28K ARGs and associated 29 resistance categories), yielding Matthew's correlation coefficients (MCCs) of 0.983 ± 0.001 by using a 5-fold cross-validation strategy. Furthermore, the PLM-ARG model was verified using an independent validation set and achieved an MCC of 0.838, outperforming other publicly available ARG prediction tools with an improvement range of 51.8%-107.9%. Moreover, the utility of the proposed PLM-ARG model was demonstrated by annotating resistance in the UniProt database and evaluating the impact of ARGs on the Earth's environmental microbiota. PLM-ARG is available for academic purposes at https://github.com/Junwu302/PLM-ARG, and a user-friendly webserver (http://www.unimd.org/PLM-ARG) is also provided.

Sequencing Quadruple Therapy for Heart Failure with Reduced Ejection Fraction: Does It Really Matter?

The conventional sequence of guideline-directed medical therapy (GDMT) initiation in heart failure with reduced ejection fraction (HFrEF) assumes that the effectiveness and tolerability of GDMT agents mirror their order of discovery, which is not true. In this review, the authors discuss flexible GDMT sequencing that should be permitted in special populations, such as patients with bradycardia, chronic kidney disease, or atrial fibrillation. Moreover, the initiation of certain GDMT medications may enable tolerance of other GDMT medications. Most importantly, the achievement of partial doses of all four pillars of GDMT is better than achievement of target dosing of only a couple.

Pretreatment synthetic MRI features for triple-negative breast cancer

To evaluate the quantitative parameters derived from synthetic magnetic resonance imaging (SyMRI) for predicting triple-negative breast cancer (TNBC). This prospective study enrolled participants with invasive ductal breast carcinoma (IDBC) and separated them into a TNBC group and a Non-TNBC group. Preoperative breast MRI included both the SyMRI and conventional MRI sequences. The quantitative parameters derived from the SyMRI included T1 and T2 relaxation times, proton density (PD), and their standard deviations (SD). Clinicopathological characteristics, conventional MRI findings, and quantitative synthetic parameters were assessed for all participants. Multivariable logistic regression analysis was performed to determine the potential independent imaging predictors for TNBC preoperatively. Receiver operating characteristic (ROC) curve analysis was used to evaluate the performance of these parameters. A total of 231 participants with histopathological proven IDBC were included in this study (n=46 in the TNBC group and n=185 in the Non-TNBC group). The TNBC group had significantly larger tumour size (p=0.011) and more frequent intratumoural cystic or necrotic lesions (p<0.001) as compared to the Non-TNBC group. The univariate analysis showed that the TNBC tumours had significantly higher T1 (p=0.006) and T2 (p<0.001) values than Non-TNBC tumours. Subsequent multivariable analysis indicated that T2 values and the presence of cystic or necrotic lesions were the independent predictors for TNBC. The T2 from synthetic imaging and the presence of cystic degeneration or necrosis within the breast cancer may serve as potential imaging biomarkers for preoperative differentiation of TNBC from Non-TNBC.

Repeatability of Quantitative Knee Cartilage T1, T2, and T1ρ Mapping With 3D-MRI Fingerprinting.

Three-dimensional MR fingerprinting (3D-MRF) techniques have been recently described for simultaneous multiparametric mapping of knee cartilage. However, investigation of repeatability remains limited. To assess the intra-day and inter-day repeatabilities of knee cartilage T1, T2, and T1ρ maps using a 3D-MRF sequence for simultaneous measurement. Prospective. Fourteen healthy subjects (35.4 ± 9.3 years, eight males), scanned on Day 1 and Day 7. 3 T/3D-MRF, T1, T2, and T1ρ maps. The acquisition of 3D-MRF cartilage (simultaneous acquisition of T1, T2, and T1ρ maps) were acquired using a dictionary pattern-matching approach. Conventional cartilage T1, T2, and T1ρ maps were acquired using variable flip angles and a modified 3D-Turbo-Flash sequence with different echo and spin-lock times, respectively, and were fitted using mono-exponential models. Each sequence was acquired on Day 1 and Day 7 with two scans on each day. The mean and SD for cartilage T1, T2, and T1ρ were calculated in five manually segmented regions of interest (ROIs), including lateral femur, lateral tibia, medial femur, medial tibia, and patella cartilages. Intra-subject and inter-subject repeatabilities were assessed using coefficient of variation (CV) and intra-class correlation coefficient (ICC), respectively, on the same day and among different days. Regression and Bland-Altman analysis were performed to compare maps between the conventional and 3D-MRF sequences. The CV in all ROIs was lower than 7.4%, 8.4%, and 7.5% and the ICC was higher than 0.56, 0.51, and 0.52 for cartilage T1, T2, and T1ρ, respectively. The MRF results had a good agreement with the conventional methods with a linear regression slope >0.61 and R2 > 0.59. The 3D-MRF sequence had high intra-subject and inter-subject repeatabilities for simultaneously measuring knee cartilage T1, T2, and T1ρ with good agreement with conventional sequences. 1 TECHNICAL EFFICACY: Stage 1.