Real-time MR-guided retrieval of inferior vena cava filters: an in vitro and animal model study.

Purpose: To develop interventional magnetic resonance (MR) guidance techniques for inferior vena cava (IVC) filter retrieval in vitro and demonstrate feasibility in vivo.

Materials And Methods: Three optional IVC filters and their retrieval systems were investigated. Experiments were performed on a 1.

Magnetic resonance imaging of carotid atherosclerotic plaque in clinically suspected acute transient ischemic attack and acute ischemic stroke.

Background: Carotid atherosclerotic plaque rupture is thought to cause transient ischemic attack (TIA) and ischemic stroke (IS). Pathological hallmarks of these plaques have been identified through observational studies. Although generally accepted, the relationship between cerebral thromboembolism and in situ atherosclerotic plaque morphology has never been directly observed noninvasively in the acute setting.

Calf muscle perfusion at peak exercise in peripheral arterial disease: measurement by first-pass contrast-enhanced magnetic resonance imaging.

Purpose: To develop a contrast-enhanced magnetic resonance (MR) technique to measure skeletal muscle perfusion in peripheral arterial disease (PAD).

Materials And Methods: A total of 11 patients (age = 61 +/- 11 years) with mild to moderate symptomatic PAD (ankle-brachial index [ABI] = 0.75 +/- 0.

Reproducibility and reliability of atherosclerotic plaque volume measurements in peripheral arterial disease with cardiovascular magnetic resonance.

A high resolution, noninvasive approach to quantify atherosclerotic plaque in the peripheral vasculature could have significant clinical and research utility. Seventeen patients with peripheral arterial disease (PAD) were studied in a 1.5T CMR scanner.

Technology insight: in vivo cell tracking by use of MRI.

Animal studies have shown some success in the use of stem cells of diverse origins to treat heart failure and ventricular dysfunction secondary to ischemic injury. The clinical use of these cells is, therefore, promising. In order to develop effective cell therapies, the location, distribution and long-term viability of these cells must be evaluated in a noninvasive manner.

Delayed calf muscle phosphocreatine recovery after exercise identifies peripheral arterial disease.

Objectives: In this study we intend to characterize phosphocreatine (PCr) recovery kinetics with phosphorus-31 ((31)P) magnetic resonance spectroscopy in symptomatic peripheral arterial disease (PAD) patients compared with control subjects and determine the diagnostic value and reproducibility of this parameter.

Background: Due to the inconsistent relationship between flow and function in PAD, novel techniques focused on the end-organ are needed to assess disease severity and measure therapeutic response.

Methods: Fourteen normal subjects (5 men, age 45 +/- 14 years) and 20 patients with mild-to-moderate symptomatic PAD (12 men, age 67 +/- 10 years, mean ankle brachial index 0.

Real-time magnetic resonance-guided placement of retrievable inferior vena cava filters: comparison with fluoroscopic guidance with use of in vitro and animal models.

Purpose: To compare the precision of magnetic resonance (MR)-guided versus fluoroscopy-guided placement of retrievable inferior vena cava (IVC) filters with use of real-time MR imaging strategies optimized for each device in an in vitro model and in an animal model.

Materials And Methods: Three different retrievable IVC filters were used in this study, including the Recovery, Günther Tulip, and OptEase devices. Experiments were performed on a 1.

Infarct involution and improved function during healing of acute myocardial infarction: the role of microvascular obstruction.

Delayed contrast-enhanced cardiac magnetic resonance imaging (ceCMR) delineates infarct size. The presence of hypoenhancement consistent with microvascular obstruction (MO) signifies larger infarcts with a worse prognosis. We hypothesized that the size of the contrast defect (CD) on ceCMR in acutely infarcted myocardium may change during infarct healing and depend upon the presence of MO.

Factors regulating macrophage endocytosis of nanoparticles: implications for targeted magnetic resonance plaque imaging.

Background: The presence of activated macrophages (Mphi) is an early and consistent marker of the inflammatory nature of atherosclerotic disease. Dextran-coated superparamagnetic iron oxide particles (SPIO) are avidly endocytosed. These particles have a strong effect on magnetic resonance signal and have been proposed as a non-invasive probe for the presence of early non-occlusive atherosclerotic disease.

Fully automated registration and warping of contrast-enhanced first-pass perfusion images.

Respiratory motion during acquisition of first-pass myocardial perfusion images results in translation, distortion from out-of-plane motion, and changes in left ventricular geometry. Together these effects make visual image analysis more difficult and limit methods of quantitative analysis of contrast kinetics. We present a fully automated registration and warping algorithm for correcting translation and geometric distortions using a statistically based image registration method.

Magnetic resonance tagging and echocardiographic response to dobutamine and functional improvement after reperfused myocardial infarction.

Objective: Our objective was to compare the qualitative response to low-dose dobutamine by echocardiography (DSE) with the quantitative response of magnetic resonance myocardial tagging (DMRT) in the prediction and evaluation of functional improvement after reperfused myocardial infarction (MI).

Methods: Twenty-two patients with a reperfused first MI (aged 51 +/- 2 years, 20 male, 13 anterior MI) were studied. On day 3 +/- 1 after MI, patients underwent both DSE and DMRT at baseline and during infusion of 5 microg/kg/min and 10 microg/kg/min of dobutamine.

Reverse remodeling and improved regional function after repair of left ventricular aneurysm.

Background: Changes in regional left ventricular mechanics after anteroapical aneurysm repair in human subjects can be studied noninvasively by means of magnetic resonance tagging. We hypothesized that left ventricular intramyocardial function would improve throughout the left ventricle after repair.

Methods: We studied 6 male patients with a left ventricular anteroapical aneurysm (mean age +/- SD, 63 +/- 5 years) using magnetic resonance tagging 3 +/- 1 weeks before and 6 +/- 1 weeks after aneurysm repair, coronary artery bypass grafting, and mitral valve repair (n = 2).