measurement-tumor-t2-relaxation-times-after-iron-oxide-nanoparticle

Measurement of Tumor T2* Relaxation Times after Iron Oxide Nanoparticle Administration

T2* relaxometry is one of the established methods to measure the effect of superparamagnetic iron oxide nanoparticles on tumor tissues with magnetic ...

Stanford University, School of Medicine

To describe approaches for determining optimal spatial and temporal resolutions for the proton resonance frequency shift method of quantitative magnetic resonance temperature imaging (MRTI) guidance of transurethral ultrasonic prostate ablation.

Effects of spatial and temporal resolution for MR image-guided thermal ablation of prostate with transurethral ultrasound.

A restricted field of view (rFOV) approach for imaging a dynamic time series of volumes of limited spatial extent within a larger subject is described. The shorter readout with rFOV-MRI can be exploited to either limit image artifacts or increase spatial resolution. To accomplish rFOV imaging of a multislice volume for a dynamic series, an outer volume suppression (OVS) preparation that saturates signal external to a cylinder through the subject is followed by slice-selective excitation and a spiral readout. The pass- and stopband efficiencies of the OVS in an agar gel phantom were 97% (+/-1.5%) and 3% (+/-1%), respectively. Profiles of the temporal signal-to-noise ratio (SNR) were measured in a phantom and an adult brain. The rFOV sequence reduced distortions from off-resonance signal and T2*-induced blurring compared to a conventional sequence. Sequence utility is demonstrated for high-resolution rFOV functional MRI (fMRI) in the visual cortex. The rFOV sequence may prove to be useful for other multislice dynamic and high-resolution imaging applications.

Restricted field of view magnetic resonance imaging of a dynamic time series.

Macrophage infiltration is a prominent feature of abdominal aortic aneurysm (AAA) progression. We used a combined imaging approach with bioluminescence (BLI) and magnetic resonance imaging (MRI) to study macrophage homing and accumulation in experimental AAA disease. Murine AAAs were created via intra-aortic infusion of porcine pancreatic elastase. Mice were imaged over 14 days after injection of prepared peritoneal macrophages. For BLI, macrophages were from transgenic mice expressing luciferase. For MRI, macrophages were labeled with iron oxide particles. Macrophage accumulation during aneurysm progression was observed by in situ BLI and by in vivo 7T MRI. Mice were sacrificed after imaging for histologic analysis. In situ BLI (n  =  32) demonstrated high signal in the AAA by days 7 and 14, which correlated significantly with macrophage number and aortic diameter. In vivo 7T MRI (n  =  13) at day 14 demonstrated T₂* signal loss in the AAA and not in sham mice. Immunohistochemistry and Prussian blue staining confirmed the presence of injected macrophages in the AAA. BLI and MRI provide complementary approaches to track macrophage homing and accumulation in experimental AAAs. Similar dual imaging strategies may aid the study of AAA biology and the evaluation of novel therapies.

Bioluminescence and magnetic resonance imaging of macrophage homing to experimental abdominal aortic aneurysms.

The purpose of this study is to evaluate the 18 kDa translocator protein (TSPO) radioligand [(18)F]N-fluoroacetyl-N-(2,5-dimethoxybenzyl)-2-phenoxyaniline ([(18)F]PBR06) as a positron emission tomography (PET) imaging biomarker of stroke-induced neuroinflammation in a rodent model.

PET imaging of stroke-induced neuroinflammation in mice using [18F]PBR06.

'Long read' sequencing methods have been used to identify previously uncharacterized structural variants that cause human genetic diseases. Therefore, we investigated whether long read sequencing could facilitate genetic analysis of murine models for human diseases.

Laura J. Pisani

Department of Radiology,
Molecular Imaging Program at Stanford,
Department of Radiology, Molecular Imaging Program at Stanford

Stanford University, School of Medicine

Measurement of Tumor T2* Relaxation Times after Iron Oxide Nanoparticle Administration

Laura J. Pisani

Department of Radiology,Molecular Imaging Program at Stanford,Department of Radiology, Molecular Imaging Program at Stanford

Stanford University, School of Medicine

Measurement of Tumor T2* Relaxation Times after Iron Oxide Nanoparticle Administration

Department of Radiology,
Molecular Imaging Program at Stanford,
Department of Radiology, Molecular Imaging Program at Stanford