Segmentation of interstitial catheters from MRI needs to be addressed in order for MRI-based brachytherapy treatment planning to become part of the clinical practice of gynecologic cancer radiotherapy. This paper presents a validation study of a novel image-processing method for catheter segmentation. The method extends the distal catheter tip, interactively provided by the physician, to its proximal end, using knowledge of catheter geometry and appearance in MRI sequences.
Cardiac MRI was performed in human volunteers to determine the magnitude of the misregistration (MSR) of cardiac landmarks due to variability in the diaphragm position for repeated breath-holds. Seven normal volunteers underwent MR imaging of the left ventricle (LV) to evaluate the magnitude of the endocardial centroid MSR. The MSR for a mid-ventricle short-axis image was 3.01 +/- 1.68 mm through-plane and 4.16 +/- 1.62 mm in-plane. A second order polynomial fit through the LV centroid coordinates minimized the in-plane component of the MSR error.
Magnetic resonance first-pass (MRFP) imaging awaits longitudinal clinical trials for quantification of myocardial perfusion. The purpose of this study was to assess inter- and intraobserver agreement of this method. Seventeen MRFP studies (14 rest and 3 under adenosine-induced hyperemia) from 14 patients were acquired. Two observers visually graded study quality. Each study was subdivided into eight regions. Both observers analyzed all 17 studies (8 x 17 = 136 regions) for interobserver agreement.
OBJECTIVE: Ultrasmall superparamagnetic iron oxide nanoparticles, such as ferumoxytol, produce decreased MR signal on susceptibility-inducing T2*-weighted sequences in tissues of the reticuloendothelial system. However, acute iron deposition in the adrenals has not been reported. The purpose of this article is to report our initial observations of the imaging behavior of the normal adrenals on ferumoxytol-enhanced T2*-weighted magnetic resonance imaging.
BACKGROUND: Recent developments in cardiac MRI have extended the potential spectrum of diagnostic and interventional applications. The purpose of this study was to test the ability of MRI to perform transcatheter closures of secundum type atrial septal defects (ASD) and to assess ASD size and changes in right cardiac chamber volumes in the same investigation.
The purpose of this article is to present some recent applications of diagnostic and interventional MRI in congenital heart disease. To date x-ray-based techniques have been the norm for most diagnostic and therapeutic applications. With the advent of ultrafast MRI and the development of MRI-compatible catheters and guide wires, the goal of achieving real-time guidance by MRI for interventions in congenital heart diseases has proven feasible.
Magnetic resonance (MR) imaging during the first pass of an injected contrast agent has been used to assess myocardial perfusion, but the quantification of blood flow has been generally judged as too complex for its clinical application. This study demonstrates the feasibility of applying model-independent deconvolution to the measured tissue residue curves to quantify myocardial perfusion. Model-independent approaches only require minimal user interaction or expertise in modeling.
BACKGROUND: Childhood obesity is a significant risk factor for cardiovascular disease in adulthood. Although ventricular remodeling has been reported in obese youth, early tissue-level markers within the myocardium that precede organ-level alterations have not been described.
BACKGROUND: The latest generation of interactive cardiac magnetic resonance (MR) scanners has made cardiac interventions with real-time MRI possible. To date, cardiac MRI has been mostly applied to measure myocardial perfusion, viability, and regional function, but now the application of cardiac MRI can be extended to cardiovascular interventions. The purpose of this article is to illustrate the potential of MRI in stem cell therapy for cardiac restoration.
PURPOSE: To develop and test a new technique for rapid, accurate three-dimensional (3D) reconstruction of the left ventricle (LV) and calculation of its volume parameters, with images from multiple orientations and interactive feedback.
