Dynamic nuclear polarization has enabled hyperpolarization of nuclei such as 13C and 15N in endogenous substances. The resulting high makes it possible to perform subsecond MRI. By using the dynamic technique, 10% was obtained an aqueous solution 100 mM 13C-labeled urea, ready for injection. vivo T1 relaxation time urea determined 20 +/- 2 s. Due long time, is use hyperpolarized substance medical imaging. A series high-resolution ( approximately 1-mm) magnetic resonance images were acquired,...

Abstract High nuclear spin polarization of 13 C was reached in organic molecules. Enhancements up to 10 4 , compared thermal at 1.5 T, were achieved using the parahydrogen‐induced technique combination with a field cycling method. While parahydrogen has no net polarization, it high order, which is retained when hydrogen incorporated into another molecule by chemical reaction. By subjecting this sudden change external magnetic field, order transferred polarization. A angiogram an animal...

Abstract Pyruvate is included in the energy production of heart muscle and metabolized into lactate, alanine, CO 2 equilibrium with HCO . The aim this study was to evaluate feasibility using 13 C hyperpolarization enhanced MRI monitor pyruvate metabolism during an ischemic episode. left circumflex artery pigs (4 months, male, 29–34 kg) occluded for 15 or 45 min followed by hr reperfusion. Pigs were examined chemical shift imaging following intravenous injection 1‐ pyruvate. MR used order...

MRI provides unsurpassed soft tissue contrast, but the inherent low sensitivity of this modality has limited clinical use to imaging water protons. With hyperpolarization techniques, signal from a given number nuclear spins can be raised more than 100 000 times. The strong enhancement enables nuclei other protons, e.g. (13)C and (15)N, their molecular distribution in vivo visualized clinically relevant time window. This article reviews different techniques some many application areas. As an...

A new strategy for a quantitative measurement of regional pulmonary ventilation using hyperpolarized helium-3 (3He) MRI has been developed. The method employs the build-up signal intensity after variable number (3)He breaths. mathematical model dynamics is presented, from which local ventilation, defined as fraction gas exchanged per breath within given volume, calculated. was used to create maps coronal slices guinea pig lungs. Ventilation values very close 1 were found in trachea and major...

A (13)C-enriched water-soluble compound (bis-1,1-(hydroxymethyl)-1-(13)C-cyclopropane-D(8)), with a (13)C-concentration of approximately 200 mM, was hyperpolarized to 15% using dynamic nuclear polarization, and then used as contrast medium (CM) for contrast-enhanced magnetic resonance angiography (CE-MRA). The long relaxation times (in vitro: T(1) 82 s, T(2) 18 s; in vivo: 38 1.3 s) are ideal steady-state free precession (SSFP) imaging true fast steady (trueFISP) pulse sequence. It shown...

A noninvasive method for in vivo measurement of the oxygen concentration has been developed. By introducing a novel contrast medium (CM) based on single electron substance, it is possible to enhance proton signal through Overhauser effect. low-field magnetic resonance scanner used image nuclei object. The spin transition CM saturated using rf irradiation. As consequence, nuclear polarization becomes enhanced dipole-dipole interaction. enhancement function power and EPR line width which...

Abstract Cerebral perfusion was assessed with 13 C MRI in a rat model after intravenous injections of the C‐labeled compound bis ‐1,1‐(hydroxymethyl)‐1‐ C‐cyclopropane‐D 8 aqueous solutions hyperpolarized by dynamic nuclear polarization (DNP). Since tracer acted as direct signal source, several problems associated techniques based on traditional susceptibility contrast (DSC) agents were avoided. Maps cerebral blood flow (CBF), volume (CBV), and mean transit time (MTT) calculated. The MTT...

A new diagnostic application of a water-soluble contrast medium (CM) based on the hyperpolarization 13C substance is introduced. The degree polarization achieved >30%, which about factor 10(5) higher than thermal equilibrium level at 1.5 T. Imaging hyperpolarized (HP) CM during cardiac interventional MRI procedure was studied. Catheters were positioned in left and right coronary arteries pigs. coil tuned to used for nonproton imaging. HP-13C ( approximately 5 ml, 0.5 M, 30% polarization)...

Background The literature on ventilation (V) and lung perfusion (Q) distributions during general anesthesia controlled mechanical in supine prone position is contradictory. authors aimed to investigate whether V, Q, ratio (V/Q ratio) matching anesthetized mechanically ventilated volunteers are gravity dependent irrespective of posture. Methods Seven healthy were studied at two different occasions ventilation. One occasion ventral dorsal V Q the posture other Imaging was performed both...

We have developed a new quantitative single-photon-emission computed tomography (SPECT) method that uses (113m)In-labeled albumin macroaggregates and Technegas ((99m)Tc) to estimate the distributions of regional ventilation perfusion for whole lung. The multiple inert-gas elimination technique (MIGET) lung respiratory gas exchange were used as physiological evaluations SPECT method. Regional estimated by in nine healthy volunteers during awake, spontaneous breathing. Radiotracers...

Body position can be optimized for pulmonary ventilation/perfusion matching during surgery and intensive care. However, positional effects upon distribution of blood flow vascular distensibility measured as the volume variation have not been quantitatively characterized. In order to explore potential clinical utility body a modulator hemodynamics, we aimed characterize gravitational flow, distension, distensibility.

Abstract A new technique for assessing tissue blood flow using hyperpolarized tracers, based on the fact that magnetization of a substance can be destroyed permanently, is described. Assessments with this are inherently insensitive to arterial delay and dispersion, allow quantification transit time dispersion in arteries supply investigated tissue. Renal cortical was studied six rabbits 13 C‐labeled compound (2‐hydroxyethylacrylate) polarized by parahydrogen‐induced polarization (PHIP)...

Animal studies have demonstrated an interaction between posture and the effect of positive end-expiratory pressure (PEEP) on regional ventilation lung blood flow. The aim this study was to explore in humans.Regional flow were compared mechanical with without PEEP supine prone postures. Six normal subjects studied each posture. Regional marked In-labeled macroaggregates Technegas (Tc). Radiotracer distributions mapped using quantitative single-photon emission computed tomography.In subjects,...

Purpose: to evaluate a new single-electron contrast agent for Overhauser-enhanced MR imaging. the agents that are currently available give enhancement factors too low make technique valid option routine clinical use Material and Methods: images were generated directly following injection of substance into rats. scanner was operated at main magnetic field 0.01 T equipped with separate rf-transmitter tuned electron paramagnetic resonance frequency Results: as expected, show high level in areas...

Both in normal subjects exposed to hypergravity and patients with acute respiratory distress syndrome, there are increased hydrostatic pressure gradients down the lung. Also, both conditions show an impaired arterial oxygenation, which is less severe prone than supine posture. The aim of this study was use further investigate mechanisms behind differences oxygenation between Ten healthy were studied a human centrifuge while 1 5 times gravity (1 G, G) anterioposterior (supine)...