Prognostic value of an increase in the serum thyroglobulin level at the time of the first ablative radioiodine treatment in patients with differentiated thyroid cancer.

Purpose: The aim of this study was to assess the prognostic factors for treatment efficacy, and in particular the increase in serum thyroglobulin (Tg) level at the time of the first ablative radioiodine treatment, in patients with differentiated thyroid carcinoma (DTC).

Methods: A retrospective chart review was performed on 407 patients treated for DTC by total thyroidectomy and (131)I ablation between 1995 and 2002, and examined 5-12 months later with diagnostic (131)I whole-body scan and serum Tg measurement after thyroid hormone treatment withdrawal. At the time of the ablative radioiodine treatment, serum Tg level was determined just before (131)I administration (TgD0) and 5 days later (TgD5); Tg variation was expressed as the ratio TgD5/TgD0.

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.

Clinical experience with 99mTc-MIBI scintimammography in patients with breast microcalcifications.

The aim of this study was to evaluate whether 99mTc-MIBI scintimammography can improve the diagnostic value of mammography for the differentiation of benign and malignant breast microcalcifications. In 41 women presenting 45 clusters of microcalcifications, a 99mTc-MIBI scintimammography was performed before open biopsy. There were 24 malignant lesions (53%).

New thermoluminescent dosimeters (TLD): optimization and characterization of TLD threads sterilizable by autoclave.

To improve the performance of mono-extruded TLD threads as a dosimetric thermoluminescent tool (French Patent 9903729), a new process was developed by co-extrusion methodology leading to threads of 600 microm diameter with a 50 microm homogeneous polypropylene sheath. In this optimization work, study of parameters such as LiF:Mg,Cu,P powder granulometry, load rate and proportion of components led to an increased sensitivity of around 40%. Moreover, the co-extrusion technique allowed the threads to be sterilized by humid steam (134 degrees C/18 min) without significant variation of the linearity response between 0 and 30 Gy after gamma irradiation (60Co).

Therapeutic efficacy of 5-fluorouracil-loaded microspheres on rat glioma: a magnetic resonance imaging study.

The aim of this work was to assess the therapeutic efficacy of an intratumoral bolus injection of 5-fluorouracil (FU) compared to that of drug loaded in biodegradable microspheres, for the treatment of brain tumour. Experiments were carried out using a fast-growing C6-glioma rat model. The therapeutic protocols were performed 12 days after the injection of glioma cells.

Nonpolymeric Coatings of Iron Oxide Colloids for Biological Use as Magnetic Resonance Imaging Contrast Agents.

Iron oxide nanoparticles are used in vivo as contrast agents in magnetic resonance imaging. Their widely used polymer coatings are directly involved in their biocompatibility and avoid magnetic aggregation. As these polymer brushes also limit their tissular diffusion due to important hydrodynamic sizes, this work looks to obtain particles coated with thin layers of organic biocompatible molecules.

In vivo quantitative microimaging of rat spinal cord at 7T.

In vivo T(2), ADC, and MT properties of the GM and WM of the rat spinal cord were measured at 7T in the cervical region. The GM T(2), T(2GM) = 43.2 +/- 1.

High-field quantitative transverse relaxation time, magnetization transfer and apparent water diffusion in experimental rat brain tumour.

The potential of quantitative parameter images of transverse relaxation time T(2), apparent diffusion coefficient (ADC) and magnetization transfer ratio (MTR) to characterize experimental brain tumours was studied. Necrosis or haemorrhage can be detected using either MTR, ADC or T(2) (necrosis-MTR reduced by 35%, ADC and T(2) increased respectively by 170% and 100% compared with normal brain tissue; haemorrhage-MTR increased by 60%, ADC and T(2) decreased by 40% and 20%, respectively). Normal brain tissue can only be distinguished from tumour on T(2) and MTR parameter images.

MRI study of transient cerebral ischemia in the gerbil: interest of T2 mapping.

Rationale And Objectives: The aim of this study was to evaluate the diagnostic use of MRI and, more precisely, the use of quantitative T2 imaging at 7 T for the early detection of neuronal cerebral alterations after transient ischemia in the gerbil.

Methods: One hundred forty-seven Mongolian gerbils were separated into four groups for which a bicarotid artery occlusion lasted for 4, 6, 8, or 10 minutes, respectively. The animals were scanned before carotid artery occlusion and at 3, 6, 10, 24, and 48 hours and 5 days after the ischemic incident.

Error assessment due to coronary stents in flow-encoded phase contrast MR angiography: a phantom study.

Phase contrast magnetic resonance imaging (PC MRI) is a promising method for assessing coronary flow. MR angiography images in the presence of coronary stents display artifacts because of the metal present in the stent. Using a flow phantom, the goal of this in vitro study was to assess quantitatively the effects of flow dephasing caused by magnetic susceptibility in velocity measurements in a region where the artifact is not visualized in a magnitude image.

[MRI quantification of regional variations of left ventricular parietal stress in normal subjects].

The object of this study was to analyse regional variations in end systolic left ventricular wall stress in normal subjects using three-dimensional magnetic resonance imaging (MRI) with excellent spatial resolution. Eight to 12 contiguous short axis sections of the left ventricle were acquired from the apex to the base in apnoea with a rapid echo-gradient sequence in 15 healthy volunteers. The end systolic wall stress was calculated by three methods: Grossman's formula (CR) using the wall thickness and radius of curvature, Janz's formula (CS) using the surfaces, and a three-dimensional approach (C3D) providing a precise calculation of the radius of curvature.

Three-dimensional coronary artery MR imaging using prospective real-time respiratory navigator and linear phase shift processing: comparison with conventional coronary angiography.

Respiratory gating with navigator echo is a recent technique to detect diaphragm position in 3D magnetic resonance (MR) coronary angiography. The purpose of our study was to image proximal coronary arteries and to detect significant stenoses in patients with coronary artery diseases and to compare with contrast enhanced angiography results. Twenty patients with coronary artery diseases who were referred for conventional angiography underwent magnetic resonance angiography (MRA).

Introduction of the closed cranial window technique in gerbils and verification by observation of the effects of specific drugs.

The exact mechanisms of cerebral arterial hypoxia are not perfectly defined. Our purpose is to adapt and validate, with drugs well known in rats and rabbits, a closed cranial window technique in gerbils. The method was used with seventeen gerbils to measure diameter changes of the pial arterioles under normoxia (after the topical application of agonists and antagonists of ATP-sensitive and Ca2+-dependent potassium channels), as well as under hypoxia.

Regional assessment of wall curvature and wall stress in left ventricle with magnetic resonance imaging.

Left ventricular functional abnormalities are associated with regional increases of wall stress and modifications of wall curvature. This study describes the integration of the short-axis and long-axis wall curvatures for determining peak systolic wall stress. Quantification was realized with cine magnetic resonance imaging (MRI) from the location of the endocardial and epicardial borders of the left ventricle on pairs of consecutive short-axis sections.

Noninvasive assessment of the infarct-related coronary artery blood flow velocity using phase-contrast magnetic resonance imaging after coronary angioplasty.

This study assesses infarct-related coronary artery blood flow velocity using phase-contrast magnetic resonance imaging (MRI) in patients with reperfused acute myocardial infarction (AMI) and compares these results with flow measurements obtained nonsimultaneously by intracoronary Doppler ultrasound. MRI examination was performed in 17 patients with AMI within 1 to 4 days (mean 2.5 days) after direct or rescue coronary angioplasty using a 0.

Improving the detection of low concentration metabolites in magnetic resonance spectroscopy by digital filtering.

In vivo detection and quantitation of metabolites is often limited by their low concentration. As far as magnetic resonance spectroscopy (MRS) is concerned, detection and quantitation can be significantly improved by reduction of the observed spectral width (SW). The reduction is limited to the spreading of resonances in the bandwidth unless high performance digital filters are used.

Thallium-201 right lung/heart ratio during exercise in patients with coronary artery disease: relation to thallium-201 myocardial single-photon emission tomography, rest and exercise left ventricular function and coronary angiography.

The aim of this study was to correlate lung thallium-201 uptake on exercise with 201Tl single-photon emission tomography (SPET) myocardial perfusion imaging, rest and exercise equilibrium radionuclide angiographic and coronary angiographic findings in patients with coronary artery disease (CAD) using a simple, reproducible lung/heart (L/H) ratio that would be easy to use in clinical practice. L/H ratio was defined on the anterior planar image obtained during exercise 201Tl SPET acquisition as the mean counts per pixel in an entire right lung field region of interest divided by the mean counts per pixel in the hottest myocardial wall region of interest. We studied 103 patients.

Early detection of liposome brain localization in rat experimental allergic encephalomyelitis.

Blood-brain barrier (BBB) permeability increases prior to the development of clinical signs in early-stage multiple sclerosis (MS). Detection of subtle changes would thus be helpful for diagnostic purposes and rapid therapeutic decisions before new episodes. Since multiple sclerosis and experimental allergic encephalomyelitis (EAE) have numerous common features, in particular BBB-permeability characteristics, and since we have previously shown that BBB localization is disturbed by tumors, embolism, and mannitol injection, we investigated BBB-liposome permeability in an EAE rat model.

Synthesis of Iron Oxide Nanoparticles Used as MRI Contrast Agents: A Parametric Study.

Colloidal iron oxides play an important role as magnetic resonance imaging (MRI) contrast agents. The superparamagnetic particles actually used are constituted by solid cores (diameter of 5-15 nm), generally coated by a thick polysaccharidic layer (hydrodynamic radii of 30-100 nm), and formulated by direct coprecipitation of iron salts in the presence of polymeric material. To better control the synthesis, we attempted to formulate new stable uncoated superparamagnetic nanoparticles.

Global left ventricular cardiac function: comparison between magnetic resonance imaging, radionuclide angiography, and contrast angiography.

Rationale And Objectives: Cardiac magnetic resonance imaging (MRI) has been shown to be a robust and noninvasive method to assess left ventricular (LV) cardiac function. This study sought to assess volumes and mass calculated with MRI using fast techniques for acquisition and postprocessing, and to compare results in terms of cost-effectiveness with those of radionuclide angiography (RNA) or contrast angiography (CA).

Methods: Thirty-five patients and 15 healthy volunteers were studied.

Phosphorylcholine Coating of Iron Oxide Nanoparticles.

In order to develop thin-walled superparamagnetic nanoparticle suspensions as a contrast agent for magnetic resonance imaging, phosphorylcholine PC was used to coat iron oxide cores of 5 nm. Weak stable positively charged suspensions can be obtained at concentration greater than 3 mmol.l-1 (corresponding to about 3.