Tumor eradication in rat glioma and bypass of immunosuppressive barriers using internal radiation with (188)Re-lipid nanocapsules.

To date, glioblastoma treatments have only been palliative. In this context, locoregional drug delivery strategies, which allow for blood--brain barrier bypass and reduced systemic toxicity, are of major significance. Recent progress in nanotechnology has led to the development of colloidal carriers of radiopharmaceutics, such as lipid nanocapsules loaded with rhenium-188 (LNC(188)Re-SSS) that are implanted in the brain.

Use of FDG-PET/CT for peritoneal carcinomatosis before hyperthermic intraperitoneal chemotherapy.

Background: Peritoneal carcinomatosis (PC) is associated with a very poor prognosis. Complete cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy has been shown to improve survival rates of PC. However, this treatment is beneficial for patients if the complete cytoreductive surgery is macroscopically completed before implementing hyperthermic intraperitoneal chemotherapy.

Susceptibility gradient quantization by MRI signal response mapping (SIRMA) to dephaser.

Purpose: Susceptibility effects are a very efficient source of contrast in magnetic resonance imaging. However, detection is hampered by the fact the induced contrast is negative. In this work, the SIgnal Response MApping (SIRMA) to dephaser method is proposed to map susceptibility gradient to improve visualization.

New starch-based radiotracer for lung perfusion scintigraphy.

Purpose: In order to avoid the microbiological risks linked to human serum albumin macroaggregates (MAA) used for lung perfusion scintigraphy, we developed a new starch-based Tc-99m potential radiopharmaceutical.

Methods: Microparticles were prepared from oxidised starch coupled to natural polyamine for Tc-99m complexation. Suspensions were formulated as ready-to-use kits for easy one-step labelling procedures.

Imaging E-selectin expression following traumatic brain injury in the rat using a targeted USPIO contrast agent.

Introduction: The aim of this work was to map E-selectin expression in a traumatic brain injury model using a newly-designed MR contrast agent. Iron cores, responsible for susceptibility effects and therefore used as T2* contrast agents, need to be coated in order to be stabilized and need to be targeted to be useful.

Methods: We have designed a molecule coating composed, at one end, of bisphosphonate to ensure anchorage of the coating on the iron core and, at the other end, of Fukuda's defined heptapeptide known to target selectin binding sites.

Mesenchymal and neural stem cells labeled with HEDP-coated SPIO nanoparticles: in vitro characterization and migration potential in rat brain.

Mesenchymal stem cells (MSC) may transdifferentiate into neural cells in vitro under the influence of matrix molecules and growth factors present in neurogenic niches. However, further experiments on the behavior of such stem cells remain to be done in vivo. In this study, rat MSC (rMSC) have been grafted in a neurogenic environment of the rat brain, the subventricular zone (SVZ), in order to detect and follow their migration using superparamagnetic iron oxide (SPIO) nanoparticles.

Uncommon breast tumor attenuation artifact on radionuclide ventriculography.

A 39-year-old woman with locally advanced left breast cancer (T4 N0 M0) underwent equilibrium radionuclide ventriculography for baseline assessment of left ventricular function before neoadjuvant chemotherapy. The left ventricular ejection fraction was 76% at 75 beats per minute, without localized wall motion abnormality. In the best septal left anterior oblique projection, a large photopenic "halo" surrounded the cardiac chambers, mimicking a pericardial effusion.

Three-dimensional MRI assessment of regional wall stress after acute myocardial infarction predicts postdischarge cardiac events.

Purpose: To determine the prognostic significance of systolic wall stress (SWS) after reperfused acute myocardial infarction (AMI) using MRI.

Materials And Methods: A total of 105 patients underwent MRI 7.8 +/- 4.

Model based and iconic multimodal registration to merge gated cardiac PET, CT and MR sequences.

In this paper, we present a multimodal registration method applied to gated positron emission tomography (PET), X-ray Computed Tomography (CT) and Magnetic Resonance (MR) cardiac images. CT images acquired on the same device as the PET ones are used as link to merge anatomical MR images and functional PET images. The registration process is divided in two steps: a 3D structure registration and a grey-levels registration.

Perfusional deficit and the dynamics of cerebral edemas in experimental traumatic brain injury using perfusion and diffusion-weighted magnetic resonance imaging.

The aim of this work was to characterize edema dynamics, cerebral blood volume, and flow alterations in an experimental model of brain trauma using quantitative diffusion and perfusion magnetic resonance imaging (MRI). Associated with an influx of water in the intracellular space 1-5 h post-trauma as demonstrated by the 40% reduction in apparent diffusion coefficient, a 70-80% reduction in cerebral blood flow was measured within the lesioned region. Transient hypoperfusion (40-50%) was also observed in the non-traumatized contralateral hemisphere, although there was no evidence of edema formation.

In vivo evaluation of lipid nanocapsules as a promising colloidal carrier for paclitaxel.

Paclitaxel-loaded lipid nanocapsules (PX-LNC) exhibit interesting in vitro characteristics with improved antitumoral activity compared with free PX formulation. Biodistribution studies were realized with the use of (14)C-trimyristin ((14)C-TM) or (14)C-phosphatidylcholine ((14)C-PC) whereas antitumoral activity of PX-LNC formulations was based on the animal survival in a chemically induced hepatocellular carcinoma (HCC) model in Wistar rats. Blood concentration-time profiles for both labeled (14)C-TM-LNC and (14)C-PC-LNC were similar; the t(1/2) and MRT values (over 2h and close to 3h, respectively, for both formulations) indicated the long circulating properties of the LNC carrier with a slow distribution and elimination phase.

Evaluating SPIO-labelled cell MR efficiency by three-dimensional quantitative T2* MRI.

An in vitro MR-assay for superparamagnetic iron oxide (SPIO) particle cell labelling assessment via three-dimensional quantitative T(2) (*) MR microscopy was proposed. On high-resolution images, and due to the high susceptibility difference between the particles and the surrounding medium, SPIO internalized in cells induces signal loss which may be counted and measured on T(2) (*) maps. The increase in both labelled cell percentage and the average perturbation volume with an added amount of iron in the incubation medium proved that intracellular iron uptake is dependent upon the initial concentration of incubation iron.

Single-scan quantitative T2* methods with susceptibility artifact reduction.

Two imaging methods, MSSAVE (Multiple echo SubSlice AVEraging imaging), based on sub-slice averaging and MGESEPI (Multiple echo Gradient-Echo Slice-Excitation Profile Imaging), based on over-sampling in the slice direction, are proposed for single-scan quantitative T(2)* evaluation with susceptibility artifact compensation. Their potentials in terms of sensitivity, minimum performance time, susceptibility artifact reduction and T(2)* quantitation quality, were compared with existing single-scan methods such as classical FLASH two- or three-dimensional or z-shimmed methods both in vitro and in vivo in normal rat brain. MGESEPI offered good quality T(2)* maps nearly free of artifacts but required a long acquisition time.

Dynamics of cerebral edema and the apparent diffusion coefficient of water changes in patients with severe traumatic brain injury. A prospective MRI study.

The distinction between intracellular (ICE) and extracellular edema (ECE) has a crucial prognostic and therapeutic importance in patients with severe traumatic brain injury (STBI). Indeed, ICE usually leads to cellular death, and maintenance of a cerebral perfusion pressure (CPP) above 70 mmHg is still under debate since this practice may increase ECE. The purpose of this study was to describe the ECE and ICE kinetics associated with STBI using quantitative diffusion MRI.

Volumetric assessment of myocardial viability in rats using 3D double contrast enhanced T1 and T2-weighted MRI.

Objective: Volumetric evaluation of the myocardial viability post-infarction in rats using 3D in vivo MR imaging at 7 T using injection of an extracellular paramagnetic contrast agent and intravascular superparamagnetic iron oxide nanoparticles in the same imaging session.

Materials And Methods: Five hours after induction of permanent myocardial infarction in rats (n=6), 3D in vivo T1- and T2-weighted MR Imaging was performed prior to and after Gd-DOTA injection (0.2 mmol/kg) and prior to and after nanoparticle injection (5 mg Fe/kg) to assess infarct size and myocardial viability.

Prenatal evaluation of kidney function in mice using dynamic contrast-enhanced magnetic resonance imaging.

Glomerular differentiation starts as soon as embryonic stage 12 in mice and suggests that kidneys may be functional at this stage. Dynamic contrast-enhanced magnetic resonance microscopy, a noninvasive imaging technique, was used to assess renal function establishment in utero. Indeed, in adults (n = 3), an intravenous injection of gadolinium-DOTA induced in a first step a massive and rapid drop in kidney signal intensity followed, in a second step, by a drop in bladder signal intensity.

Routine breath-hold gradient echo MRI-derived right ventricular mass, volumes and function: accuracy, reproducibility and coherence study.

Right ventricular (RV) dysfunction is a predictor of poor outcome in patients with heart disease. Conventional imaging modalities fail to assess RV volumes accurately. We sought to assess the accuracy and reproducibility of routine breath-hold gradient echo magnetic resonance imaging (MRI)-derived RV mass, volumes and function.

Characterization and detection of experimental rat gliomas using magnetic resonance imaging.

Two different experimental rat brain tumours (F98 glioma and 9L glioma) were characterized using T1 and T2, apparent diffusion coefficient (ADC) and magnetization transfer ratio (MTR). Even though both tumours appeared homogenous at the early stage of growth, significant differences were measured for all parametric images between tumours and normal brain tissue. Irrespective of the sequence used, tumour lesion/normal parenchyma contrast for the non-infiltrative 9L was twice that of the infiltrative F98 glioma.

Assessment of myocardial viability in rats: Evaluation of a new method using superparamagnetic iron oxide nanoparticles and Gd-DOTA at high magnetic field.

The aim of this study was to detect salvageable peri-infarction myocardium by MRI in rats after infarction, using with a double contrast agent (CA) protocol at 7 Tesla. Intravascular superparamagnetic iron oxide (SPIO) nanoparticles and an extracellular paramagnetic CA (Gd-DOTA) were used to characterize the peri-infarction zone, which may recover function after reperfusion occurs. Infarcted areas measured from T1-weighted (T1-w) images post Gd-DOTA administration were overestimated compared to histological TTC staining (52% +/- 3% of LV surface area vs.

Assessment of biventricular remodeling by magnetic resonance imaging after successful primary stenting for acute myocardial infarction.

Inferior acute myocardial infarction (AMI) is associated with a better outcome compared with anterior AMI, even in the presence of comparable infarct size. Whether left ventricular remodeling, a major predictor of poor outcome, and right ventricular (RV) remodeling depend on the site of an AMI remains unknown. Biventricular volumes were assessed by magnetic resonance imaging 7 +/- 2 days and 3.

High field magnetic resonance imaging evaluation of superparamagnetic iron oxide nanoparticles in a permanent rat myocardial infarction.

Rationale And Objectives: The purpose of this study was to evaluate superparamagnetic iron oxide (SPIO) nanoparticles to discriminate infarcted from normal tissue after myocardial infarction using high field MR imaging (7 tesla).

Materials And Methods: Permanent myocardial infarction was induced in rats. SPIO nanoparticles (1 mg Fe/kg) were assessed with T1-weighted gradient echo sequence to visualize the myocardial infarction 48 hours after ligature (n = 6).