Accelerated F·MRI Detection of Matrix Metalloproteinase-2/-9 through Responsive Deactivation of Paramagnetic Relaxation Enhancement.

Paramagnetic gadolinium ions (Gd), complexed within DOTA-based chelates, have become useful tools to increase the magnetic resonance imaging (MRI) contrast in tissues of interest. Recently, "on/off" probes serving as F·MRI biosensors for target enzymes have emerged that utilize the increase in transverse ( or ) relaxation times upon cleavage of the paramagnetic Gd centre. Molecular F·MRI has the advantage of high specificity due to the lack of background signal but suffers from low signal intensity that leads to low spatial resolution and long recording times.

Myoinositol CEST signal in animals with increased Iba-1 levels in response to an inflammatory challenge-Preliminary findings.

Neuroinflammation plays an important role in the pathogenesis of a range of brain disorders. Non-invasive imaging of neuroinflammation is critical to help improve our understanding of the underlying disease mechanisms, monitor therapies and guide drug development. Generally, MRI lacks specificity to molecular imaging biomarkers, but molecular MR imaging based on chemical exchange saturation transfer (CEST) can potentially detect changes of myoinositol, a putative glial marker that may index neuroinflammation.

Developing Mn-doped lead sulfide quantum dots for MRI labels.

Magnetic interactions of Mn ions in lead sulfide (PbS) nanocrystals with protons in water are probed by NMR and MRI. A thin layer of capping molecules enables free solvent diffusion to the nanocrystal surface resulting in a decrease of proton relaxation times. Magnetic resonance imaging of neuronal cell pellets exposed to (PbMn)S at non-toxic concentrations demonstrates their prospects as MRI-labels.

Probe-Specific Procedure to Estimate Sensitivity and Detection Limits for 19F Magnetic Resonance Imaging.

Due to low fluorine background signal in vivo, 19F is a good marker to study the fate of exogenous molecules by magnetic resonance imaging (MRI) using equilibrium nuclear spin polarization schemes. Since 19F MRI applications require high sensitivity, it can be important to assess experimental feasibility during the design stage already by estimating the minimum detectable fluorine concentration. Here we propose a simple method for the calibration of MRI hardware, providing sensitivity estimates for a given scanner and coil configuration.

Molecular Sensing with Hyperpolarized (129) Xe Using Switchable Chemical Exchange Relaxation Transfer.

An approach for hyperpolarized (129) Xe molecular sensors is explored using paramagnetic relaxation agents that can be deactivated upon chemical or enzymatic reaction with an analyte. Cryptophane encapsulated (129) Xe within the vicinity of the paramagnetic center experiences fast relaxation that, through chemical exchange of xenon atoms between cage and solvent pool, causes accelerated hyperpolarized (129) Xe signal decay in the dissolved phase. In this proof-of-concept work, the relaxivity of Gadolinium(III) -DOTA on (129) Xe in the solvent was increased eightfold through tethering of the paramagnetic molecule to a cryptophane cage.