Background: Imaging of the lung by MRI is challenging due to the intrinsic low proton density and rapid T 2 * relaxation. MRI methods providing lung parenchyma and function are in demand. Purpose: To investigate the feasibility of two-dimensional ultrashort echo-time (2D UTE) imaging for lung function assessment. Study Type: Prospective. Population: Eleven healthy volunteers. Field Strength/Sequence: 3T, 2D tiny golden angle UTE (2D-tyUTE). Assessment: The applicability of breath-hold (BH) and self-gated (SG) 2D-tyUTE for quantification of the lung parenchyma signal-to-noise ratio (SNR), proton fraction (f P), fractional ventilation (FV), and perfusion (f) was investigated. Dependencies on repetition time (BH S/I1/I2) and respiratory phase (expiration [EX], inspiration [IN]) were investigated and compared between smokers and nonsmokers.
Cardiovascular magnetic resonance imaging has proven valuable for the assessment of structural and functional cardiac abnormalities. Even although it is an established imaging method in small animals, the long acquisition times of gated or self-gated techniques still limit its widespread application. In this study, the application of tiny golden angle radial sparse MRI (tyGRASP) for real-time cardiac imaging was tested in 12 constitutive nexilin (Nexn) knock-out (KO) mice, both heterozygous (Het, N = 6) and wild-type (WT, N = 6), and the resulting functional parameters were compared with a well-established self-gating approach. Real-time images were reconstructed for different temporal resolutions of between 16.8 and 79.8 ms per image. The suggested approach was additionally tested for dobutamine stress and qualitative first-pass perfusion imaging. Measurements were repeated twice within 2 weeks for reproducibility assessment. In direct comparison with the high-quality, self-gated technique, the real-time approach did not show any significant differences in global function parameters for acquisition times below 50 ms (rest) and 31.5 ms (stress).Compared with WT, the end-diastolic volume (EDV) and end-systolic volume (ESV) were markedly higher (P < 0.05) and the ejection fraction (EF) was significantly lower in the Het Nexn-KO mice at rest (P < 0.001). For the stress investigation, a clear decrease of EDV and ESV, and an increase in EF, but maintained stroke volume, could be observed in both groups. Combined with ECG-triggering, tyGRASP provided firstpass perfusion data with a temporal resolution of one image per heartbeat, allowing the quantitative assessment of upslope curves in the blood-pool and myocardium.Excellent inter-study reproducibility was achieved in all the functional parameters.The tyGRASP is a valuable real-time MRI technique for mice, which significantly reduces the scan time in preclinical cardiac functional imaging, providing sufficient image quality for deriving accurate functional parameters, and has the potential to investigate real-time and beat-to-beat changes.
Cardiovascular magnetic resonance (CMR) imaging has become an accurate and versatile imaging modality to visualize the cardiovascular system in normal or abnormal conditions. In preclinical research, small rodent animal models of human cardiovascular diseases are frequently used to investigate the basic underlying mechanism of normal and abnormal cardiac function and for monitoring the disease progression under therapy. Technical improvements have enabled the transfer of CMR to small animal research, and as such made this non-invasive technique available to provide insights into cardiac morphology, function, perfusion, and pathophysiology in small animal cardiac disease models. This article reviews the basic technical approaches to in vivo small animal magnetic resonance imaging and its variants for the most promising applications.
The current study compared criminal defendants' perceptions of attorney-client working relationship variables across in-person and videoconferencing consultation modalities. Defendants participated in pre-trial consultations with their defense attorneys either inperson (n ϭ 22) or via videoconference (n ϭ 21) and then completed a series of measures assessing their perceptions of working alliance, trust, procedural fairness, and satisfaction with attorney services. Results of a series of multivariate analyses of variance (MANOVA) procedures, independent samples t-tests, and Mann-Whitney U tests revealed no significant between-group differences in defendants' ratings of each of these variables. In addition, estimates of effect size indicated generally small experimental effects. Examination of descriptive and frequency statistics indicated defendants provided positive ratings of videoconference consultations. These findings are considered to be preliminary given the methodological limitations of this study; however, results suggested that core components of the attorney-client working relationship were not significantly altered with the use of videoconferencing. Furthermore, results suggested defendants found videoconferencing to be an acceptable medium for facilitating attorney-client pre-trial consultations. These results are consistent with research findings regarding the acceptability of correctional telehealth and telemental health services, and extend this research to the domain of attorney-client consultations. Implications for legal practice and policy are discussed, as is the need for further research in this area.
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