Multiparametric human hepatocellular carcinoma characterization and therapy response evaluation by hyperpolarized (13) C MRSI.

Individual tumor characterization and treatment response monitoring based on current medical imaging methods remain challenging. This work investigates hyperpolarized (13) C compounds in an orthotopic rat hepatocellular carcinoma (HCC) model system before and after transcatheter arterial embolization (TAE). HCC ranks amongst the top six most common cancer types in humans and accounts for one-third of cancer-related deaths worldwide.

Investigation of metabolic changes in STZ-induced diabetic rats with hyperpolarized [1-13C]acetate.

In the metabolism of acetate several enzymes are involved, which play an important role in free fatty acid oxidation. Fatty acid metabolism is altered in diabetes patients and therefore acetate might serve as a marker for pathological changes in the fuel selection of cells, as these changes occur in diabetes patients. Acetylcarnitine is a metabolic product of acetate, which enables its transport into the mitochondria for energy production.

Comparison of acquisition schemes for hyperpolarised ¹³C imaging.

The aim of this study was to characterise and compare widely used acquisition strategies for hyperpolarised (13)C imaging. Free induction decay chemical shift imaging (FIDCSI), echo-planar spectroscopic imaging (EPSI), IDEAL spiral chemical shift imaging (ISPCSI) and spiral chemical shift imaging (SPCSI) sequences were designed for two different regimes of spatial resolution. Their characteristics were studied in simulations and in tumour-bearing rats after injection of hyperpolarised [1-(13)C]pyruvate on a clinical 3-T scanner.

Metabolic imaging of hyperpolarized [1-(13) C]acetate and [1-(13) C]acetylcarnitine - investigation of the influence of dobutamine induced stress.

Purpose: The metabolism of acetate in the heart resembles fatty acid metabolism, which is altered in several diseases like ischemia, diabetes mellitus, and heart failure. A signal-to-noise ratio (SNR) optimized imaging framework for in vivo measurements of hyperpolarized [1-(13) C]acetate and its metabolic product [1-(13) C]acetylcarnitine (ALCAR) in rats at 3 Tesla (T) is presented in this work.

Methods: A spectrospatial pulse was combined with IDEAL encoding to acquire well separated metabolic maps.

Synthesis and preliminary evaluation in tumor bearing mice of new (18)F-labeled arylsulfone matrix metalloproteinase inhibitors as tracers for positron emission tomography.

New fluorinated, arylsulfone-based matrix metalloproteinase (MMP) inhibitors containing carboxylate as the zinc binding group were synthesized as radiotracers for positron emission tomography. Inhibitors were characterized by Ki for MMP-2 in the nanomolar range and by a fair selectivity for MMP-2/9/12/13 over MMP-1/3/14. Two of these compounds were obtained in the (18)F-radiolabeled form, with radiochemical purity and yield suitable for preliminary studies in mice xenografted with a human U-87 MG glioblastoma.

Earth's magnetic field enabled scalar coupling relaxation of 13C nuclei bound to fast-relaxing quadrupolar 14N in amide groups.

Scalar coupling relaxation, which is usually only associated with closely resonant nuclei (e.g., (79)Br-(13)C), can be a very effective relaxation mechanism.

Novel Gd(III)-based probes for MR molecular imaging of matrix metalloproteinases.

Two novel Gd-based contrast agents (CAs) for the molecular imaging of matrix metalloproteinases (MMPs) were synthetized and characterized in vitro and in vivo. These probes were based on the PLG*LWAR peptide sequence, known to be hydrolyzed between Gly and Leu by a broad panel of MMPs. A Gd-DOTA chelate was conjugated to the N-terminal position through an amide bond, either directly to proline (compd Gd-K11) or through a hydrophilic spacer (compd Gd-K11N).