The STI estimation of LVtor is concordant with those analyzed by tagged MRI (data derived from tissue displacement) and also showed good agreement with those by DTI (data derived from tissue velocity). Ultrasound STI is a promising new method to assess LV torsional deformation and may make the assessment more available in clinical and research cardiology.

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The need for ECG gating presents many difficulties in cardiac magnetic resonance imaging (CMRI). Real-time imaging techniques eliminate the need for ECG gating in cine CMRI, but they cannot offer the spatial and temporal resolution provided by segmented acquisition techniques. Previous MR signal-based techniques have demonstrated an ability to provide cardiac gating information; however, these techniques result in decreased imaging efficiency. The purpose of this work was to develop a new "self-gated" (SG) acquisition technique that eliminates these efficiency deficits by extracting the motion synchronization signal directly from the same MR signals used for image reconstruction. Three separate strategies are proposed for deriving the SG signal from data acquired using radial k-space sampling: echo peak magnitude, kymogram, and 2D correlation. The SG techniques were performed on seven normal volunteers. A comparison of the results showed that they provided cine image series with no significant differences in image quality compared to that obtained with conventional ECG gating techniques. SG techniques represent an important practical advance in clinical MRI because they enable the acquisition of high temporal and spatial resolution cardiac cine images without the need for ECG gating and with no loss in imaging efficiency.

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Standardized quantification of CAC yielded comparable image noise, spatial resolution, and mass scores among different patient sizes and different CT systems and facilitated reduced radiation dose for small and medium-size patients.

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Objective. Previous studies have confirmed the poor correlation of symptoms, signs, and levels of acute-phase reactants with disease activity in ϳ50% of all patients with Takayasu arteritis (TA). Invasive angiographic studies demonstrate vessel lumen anatomy, but do not provide qualitative information about the vessel wall. Moreover, sequential invasive angiographic studies expose patients to high-dose ionizing radiation and catheter/procedure-related morbidity. The aim of the present study was to determine the utility of new developments in vascular magnetic resonance (MR) technology in patients with TA.Methods. Electrocardiogram-gated "edemaweighted" MR was used to evaluate the aorta and its primary branches with regard to the vascular lumen, vessel wall anatomy, and vessel wall edema in 24 TA patients (77 studies). Inclusion criteria were age <50 years and features of TA on both clinical examination and invasive angiographic studies. Patients were stratified based on clinical and laboratory indications of having either unequivocally active disease, inactive disease, or uncertain disease status.Results. MR revealed vessel wall edema in 94% (17 of 18), 81% (13 of 16), and 56% (24 of 43) of studies obtained during periods of unequivocally active disease, uncertain disease activity, and apparent clinical remission, respectively. Westergren erythrocyte sedimentation rate and C-reactive protein values did not correlate with either the clinical assessment of disease activity or MR evidence of vascular edema. The frequency of presumed vascular inflammation (edema), as assessed by MR, in patients who appeared to be in remission was similar to the reported frequency of new angiographic lesions and histopathologic evidence of active disease in surgical specimens from patients thought to be in remission. However, the presence of edema within vessel walls did not consistently correlate with the occurrence of new anatomic changes found on subsequent studies.Conclusion. Inconsistencies in the presence or absence of vessel edema and subsequent anatomic changes have cast doubt on the utility of edemaweighted MR imaging as a sole guide to disease activity and treatment in TA. In this study, the greatest utility of MR was in providing a safe, noninvasive means of assessing changes in vascular anatomy.

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