Combined use of the intravascular blood-pool agent, gadomer, and carbon dioxide: a novel type of double-contrast magnetic resonance angiography (MRA).

Purpose: To evaluate the combined use of carbon dioxide (CO(2)) and a gadolinium-based blood-pool agent for magnetic resonance angiography (MRA).

Materials And Methods: After an initial intravenous injection of the blood-pool agent Gadomer (Schering AG, Germany), repeated transcatheter CO(2) injections were performed in the aorta and the renal arteries of two fully-anesthetized pigs. Real-time images were acquired using a true fast imaging with steady-state precession (FISP) sequence.

Rapid quantum mechanical models for the computational estimation of C-H bond dissociation energies as a measure of metabolic stability.

Several relatively inexpensive levels of theory are surveyed together with alternative algorithmic methods for the estimation of C-H bond dissociation energies (BDEs), such energies being useful for the prediction of metabolic stability in drug-like molecules. In particular, bond stretching potentials of several C-H bonds are computed using the AM1, PM3, HF/MIDI!, and B3LYP/MIDI! levels of electronic structure theory, and selected points are fit to Morse and parabolic potentials. BDEs computed by an AM1 fit to the Morse function show the smallest mean unsigned error in prediction (+/- 3-4 kcal/mol) over 32 diverse C-H bonds.

Functional cardiac CT and MR: effects of heart rate and software applications on measurement validity.

This study sought to validate different software applications for cardiac function analysis using ECG-gated CT and MR datasets in correlation with underlying heart rate. Ten patients and a set of ventricular phantoms underwent concurrent multislice-CT and cine-MR imaging for evaluation of cardiac function. Datasets from both imaging modalities were evaluated utilizing 2 volumetric analysis tools to determine left ventricular volume and mass.

Comparison of ECG-gated rectilinear vs. real-time radial K-space sampling schemes in cine True-FISP cardiac MRI.

Purpose: To compare three k-space sampling schemes in cine True-FISP cardiac magnetic resonance imaging and to evaluate changes in calculated quantitative functional cardiac parameters as a function of underlying k-space sampling techniques.

Material And Methods: Using a 1.5 T MR imaging system (Magnetom Sonata, Siemens Medical Solutions, Erlangen, Germany), three k-space data-sampling schemes: rectilinear (2.

Fast Spiral two-point Dixon technique using block regional off-resonance correction.

The Spiral two-point Dixon (Spiral 2PD) technique has recently been proposed as a method for unambiguous water-fat decomposition in spiral imaging. It also corrects for off-resonance blurring artifacts using only two data sets. In the Spiral 2PD technique, several predetermined off-resonance frequencies are tested to both separate water and fat signals and deblur the decomposed images.

DNA methylation profiling of the human major histocompatibility complex: a pilot study for the human epigenome project.

The Human Epigenome Project aims to identify, catalogue, and interpret genome-wide DNA methylation phenomena. Occurring naturally on cytosine bases at cytosine-guanine dinucleotides, DNA methylation is intimately involved in diverse biological processes and the aetiology of many diseases. Differentially methylated cytosines give rise to distinct profiles, thought to be specific for gene activity, tissue type, and disease state.

Low-flow vascular malformations: MR-guided percutaneous sclerotherapy in qualitative and quantitative assessment of therapy and outcome.

Purpose: To prospectively assess the therapeutic procedure and outcome of magnetic resonance (MR)-guided percutaneous sclerotherapy in patients with low-flow vascular malformations.

Materials And Methods: Seventy-six percutaneous sclerotherapy treatments were performed by one radiologist with real-time MR guidance in 15 patients (six female patients; mean age, 54.4 years +/- 11.

Endolymphatic duct violation during retrosigmoid dissection of the internal auditory canal: a human temporal bone radiographic study.

Objective/hypothesis: Successful hearing preservation after acoustic neuroma resection is sometimes complicated by delayed hearing deterioration. The goal of this study was to investigate the hypothesis that internal auditory canal (IAC) drilling during retrosigmoid acoustic neuroma removal may result in endolymphatic duct (ELD) injury, a potential cause of delayed hearing loss (HL) after hearing preservation surgery.

Study Design: Temporal bone anatomic and radiographic study and literature review.

Volumetric assessment of pulmonary nodules with ECG-gated MDCT.

Objective: The objective of our study was to assess physiologic lung deformation and compression originating from cardiovascular motion and their subsequent impact on determining the volume of small pulmonary nodules throughout the cardiac cycle on ECG-gated MDCT.

Subjects And Methods: Seventy-three small noncalcified pulmonary nodules were identified in 30 patients who underwent ECG-gated MDCT. The volume of each nodule was assessed throughout the cardiac cycle using computer-aided automatic segmentation algorithms, and the assessment was repeated three times.

An Augmented Reality system for MRI-guided needle biopsies.

A navigation system can increase the speed and accuracy of MR guided interventions that make use of scanners with high-field closed magnets. We report on first needle placement experiments performed with an Augmented Reality (AR) navigation system. AR visualization provides very intuitive guidance, resulting in a faster procedure.

Optimal design of k-space trajectories using a multi-objective genetic algorithm.

Spiral, radial, and other nonrectilinear k-space trajectories are an area of active research in MRI due largely to their typically rapid acquisition times and benign artifact patterns. Trajectory design has commonly proceeded from a description of a simple shape to an investigation of its properties, because there is no general theory for the derivation of new trajectories with specific properties. Here such a generalized methodology is described.

Digital mammography.

Despite its technical advantages, early clinical trials comparing digital mammography with film mammography for screening have been somewhat disappointing. Digital mammography,however, is in its infancy and can be expected to improve more rapidly than film mammography. Some areas of improvement being observed now include the development of new detector technologies; more powerful and better-designed interpretation workstations; and novel advanced applications, such as tomosynthesis and contrast-enhanced mammography, which are not possible with standard film mammography.

Phase II clinical trial of interactive MR imaging-guided interstitial radiofrequency thermal ablation of primary kidney tumors: initial experience.

Purpose: To perform a phase II clinical trial to evaluate efficacy and safety of interactive magnetic resonance (MR) imaging-guided radiofrequency (RF) interstitial thermal ablation (ITA) of primary renal tumors.

Materials And Methods: Ten male patients (age range, 25-83 years) with peripheral renal cell carcinoma and contraindications to surgery were treated with percutaneous RF ITA entirely guided and monitored with a 0.2-T MR imaging unit.

MRI-guided radiofrequency thermal ablation of normal lung tissue: in vivo study in a rabbit model.

Objective: The purpose of this study was to assess the feasibility of MRI to guide and monitor radiofrequency ablation of normal pulmonary tissue in a rabbit model.

Materials And Methods: Percutaneous puncture and lung radiofrequency ablation were performed in six New Zealand white rabbits under MRI control using a 0.2-T open MRI scanner.

Radiofrequency thermal ablation: correlation of hyperacute MR lesion images with tissue response.

Purpose: To investigate the hypothesis that the outer boundary of the hyperintense region observed in hyperacute (several minutes post-ablation) T2 and gadolinium contrast-enhanced (CE) T1-weighted magnetic resonance (MR) lesion images is an accurate predictor of eventual cell death from radiofrequency (RF) thermal ablation.

Materials And Methods: A low-field, open MR imaging system was used to guide an ablation electrode into a thigh muscle of five rabbits and acquire in vivo T2 and CE T1-weighted MR volumes. Ablation occurred by applying RF current for two minutes with the electrode's temperature maintained at 90 degrees +/- 2 degrees C.

High-resolution MRI enhances identification of lesions amenable to surgical therapy in children with intractable epilepsy.

Purpose: Many children with refractory epilepsy can achieve better seizure control with surgical therapy. An abnormality on magnetic resonance imaging (MRI), along with corroborating localization by other modalities, markedly increases chances of successful surgical outcome. We studied the impact of high-resolution MRI on the surgical outcome of intractable epilepsy.

The catheter-driven MRI scanner: a new approach to intravascular catheter tracking and imaging-parameter adjustment for interventional MRI.

Objective: Our aim was to test the feasibility of a hands-free approach to MRI that allows the interventionalist to track an angiographic catheter in real time throughout the procedure and to automatically change imaging parameters by catheter manipulation.

Materials And Methods: A tracking method that is based on an active device localization was implemented on a 1.5-T MRI scanner.

Quantitative DNA methylation analysis based on four-dye trace data from direct sequencing of PCR amplificates.

Motivation: Methylation of cytosines in DNA plays an important role in the regulation of gene expression, and the analysis of methylation patterns is fundamental for the understanding of cell differentiation, aging processes, diseases and cancer development. Such analysis has been limited, because technologies for detailed and efficient high-throughput studies have not been available. We have developed a novel quantitative methylation analysis algorithm and workflow based on direct DNA sequencing of PCR products from bisulfite-treated DNA with high-throughput sequencing machines.

Percutaneous transcricoid jet ventilation compared with surgical cricothyroidotomy in a sheep airway salvage model.

Background: We developed a large animal model of the "cannot intubate/cannot ventilate" (CNI/V) scenario to compare percutaneous transcricoid manual jet ventilation (MJV) with surgical cricothyroidotomy (SC).

Methods: Twelve sheep weighing 40-80 kg were assigned to MJV or SC groups. After sedation, intubation, and line placement, CNI/V was simulated by removing the tracheal tube and inducing paralysis with vecuronium.

Assessment of parallel acquisition techniques in adrenal magnetic resonance imaging: does increased temporal resolution significantly improve visualization of adrenal lesions?

Rationale And Objectives: To compare conventional radiofrequency coil reception techniques with parallel coil array acquisition methods in adrenal tissue visualization and to evaluate the dependence of temporal resolution on image quality in adrenal magnetic resonance magnetic resonance (MR) imaging.

Material And Methods: Using a 1.5 T MR imager, conventional and parallel sampled sequences were acquired in 10 healthy volunteers and 10 patients with adrenal lesions.

Nonsurgical management of the stoma to maximize tracheoesophageal speech.

The anatomic site for respiratory exchange following total laryngectomy is the tracheostoma, which plays a key role in restoring pulmonary function in all laryngectomized patients and in restoring speech in patients who use tracheoesophageal (TE) voice production. Variations in stomal size, shape, and location are challenges in restoring speech and pulmonary function following total laryngectomy and TE puncture. A large, irregularly shaped, or recessed stoma that prevents adequate stomal occlusion or a small stoma that inhibits placement of a TE voice prosthesis is frustrating to the patient and requires creative management strategies.

Comparison of MR imaging sequences for liver and head and neck interventions: is there a single optimal sequence for all purposes?

Rationale And Objectives: To compare the appropriate pulse sequences for interventional device guidance during magnetic resonance (MR) imaging at 0.2 T and to evaluate the dependence of sequence selection on the anatomic region of the procedure.

Materials And Methods: Using a C-arm 0.

Suppression of prostate carcinogenesis by dietary supplementation of celecoxib in transgenic adenocarcinoma of the mouse prostate model.

Epidemiological studies and clinical observations suggest that nonsteroidal anti-inflammatory drugs and certain selective cyclooxygenase (COX)-2 inhibitors may reduce the relative risk of clinically evident prostate cancer. This prompted us to investigate the chemopreventive potential of celecoxib, a selective COX-2 inhibitor, against prostate carcinogenesis in a transgenic adenocarcinoma of the mouse prostate (TRAMP) model. Similar to prostate cancer in humans, prostate malignancies in TRAMP mice progress from precursor intraepithelial lesions, to invasive carcinoma that metastasizes to lymph nodes, liver, lungs, and occasionally to bone.

Assessment of automatic vessel tracking techniques in preoperative planning of transluminal aortic stent graft implantation.

Objective: To evaluate automatic vessel tracking techniques in the course of preoperative planning prior to transluminal aortic endograft implantation by comparing accuracy, reproducibility, and postprocessing time with source image and volume-rendered analysis methods.

Methods: Multislice computed tomography datasets of 5 patients with abdominal aortic aneurysms were preoperatively examined, performing volumetric analysis of diameter and position of renal artery orifices, aneurysmal neck, maximal aneurysmal extension, aortic bifurcation, and iliac arteries and bifurcation. Analysis was realized by utilizing transverse datasets, volume rendering, and automated vessel tracking strategies (MxView, Philips, Best, The Netherlands).