MR-guided interventional procedures can be performed with full patient access with use of an open-configuration, superconducting MR magnet with near real-time imaging and interactive image plane control.

This is an application of new longitudinal structural equation modeling techniques to time-dependent associations of memory and brain structure measurements. There were 225 participants aged 30-80 years at baseline who were measured again after a 7-year interval on both the lateral ventricular size and Wechsler memory score. Multiple regression analyses show nonlinear associations with age but no relationships among longitudinal changes. Mixed-effects latent growth curve analyses and analyses based on latent difference scores indicate that longitudinal changes in both variables are reasonably well described by an exponential or dual change model. Bivariate dynamic structural equation modeling analyses indicate age-lagged changes operate in a coupled-over-time fashion, with the brain measure (lateral ventricular size) as a leading indicator in time of memory (Wechsler memory score) declines.

Findings of two-dimensional time-of-flight magnetic resonance (MR) angiography projection angiograms were prospectively compared with those of color Doppler sonography by using angiography as a standard in 23 consecutive patients (42 carotid bifurcations) to evaluate their utility in determining the presence of carotid artery stenosis. MR angiography helped detect 50% or greater lumen diameter stenosis (sensitivity, 0.96; specificity, 0.64). Color Doppler sonography with 1.25 m/sec peak systolic velocity as a threshold had a sensitivity of 0.96 and a specificity of 0.71. Statistical analysis showed a correlation between percentage of lumen diameter narrowing and the length of the zone of signal intensity loss with MR angiography (r = .69; P less than .0001). A stronger relationship was obtained between angiographic narrowing and peak systolic velocity derived from color Doppler sonography (r = .80; P less than .0001). Two-dimensional time-of-flight MR angiography displayed as projection angiograms and combined with carotid artery and combined with carotid artery sonography is a useful approach for helping detect and potentially grade the severity of stenoses of the carotid artery.

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The 3D imaging of the middle ear facilitates better understanding of the patient's anatomy. Cross-sectional slices, however, often allow a more accurate evaluation of anatomical structures, as some detail may be lost through post-processing. In order to demonstrate the advantages of combining both approaches, we performed computed tomography (CT) imaging in two normal and 15 different pathological cases, and the 3D models were correlated to the cross-sectional CT slices. Reconstructed CT datasets were acquired by multi-slice CT. Post-processing was performed using the in-house software "3D Slicer", applying thresholding and manual segmentation. 3D models of the individual anatomical structures were generated and displayed in different colours. The display of relevant anatomical and pathological structures was evaluated in the greyscale 2D slices, 3D images, and the 2D slices showing the segmented 2D anatomy in different colours for each structure. Correlating 2D slices to the 3D models and virtual endoscopy helps to combine the advantages of each method. As generating 3D models can be extremely time-consuming, this approach can be a clinically applicable way of gaining a 3D understanding of the patient's anatomy by using models as a reference. Furthermore, it can help radiologists and otolaryngologists evaluating the 2D slices by adding the correct 3D information that would otherwise have to be mentally integrated. The method can be applied to radiological diagnosis, surgical planning, and especially, to teaching.