Interim heterogeneity changes measured using entropy texture features on T2-weighted MRI at 3.0 T are associated with pathological response to neoadjuvant chemotherapy in primary breast cancer.

Objectives: To investigate whether interim changes in hetereogeneity (measured using entropy features) on MRI were associated with pathological residual cancer burden (RCB) at final surgery in patients receiving neoadjuvant chemotherapy (NAC) for primary breast cancer.

Methods: This was a retrospective study of 88 consenting women (age: 30-79 years). Scanning was performed on a 3.

Magnetic resonance imaging texture analysis classification of primary breast cancer.

Objectives: Patient-tailored treatments for breast cancer are based on histological and immunohistochemical (IHC) subtypes. Magnetic Resonance Imaging (MRI) texture analysis (TA) may be useful in non-invasive lesion subtype classification.

Methods: Women with newly diagnosed primary breast cancer underwent pre-treatment dynamic contrast-enhanced breast MRI.

Quantitative analysis of cardiac left ventricular variables obtained by MRI at 3 T: a pre- and post-contrast comparison.

Short-axis cine images are acquired during cardiac MRI in order to determine variables of cardiac left ventricular (LV) function such as ejection fraction (EF), end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV) and LV mass. In cardiac perfusion assessments this imaging can be performed in the temporal window between first pass perfusion and the acquisition of delayed enhancement images in order to minimise overall scanning time. The objective of this study was to compare pre- and post-contrast short-axis LV variables of 15 healthy volunteers using a two-dimensional cardiac-gated segmented cine true fast imaging with steady state precession sequence and a 3.

The influence of field strength and different clinical breast MRI protocols on the outcome of texture analysis using foam phantoms.

Purpose: Texture analysis (TA) has proved to be useful to distinguish different tissues and disease states using magnetic resonance imaging (MRI). TA has been successfully applied clinically to improve identification of abnormalities in the brain, liver, and bone and, more recently, has been used to enhance the specificity of breast MRI. This preclinical study used a custom-made phantom containing different grades of reticulated foam embedded in agarose gel to assess the capability of TA to distinguish between different texture objects, under different imaging conditions.

Safety of orthopedic implants in magnetic resonance imaging: an experimental verification.

Magnetic resonance imaging (MRI) is an indispensable tool for musculoskeletal imaging. The presence of metal, however, raises concerns. The potential risks are loosening and migration of the implant, heating of the metal with surrounding tissue, causing thermal damage, and artifactual distortion which compromise the diagnostic value of the procedure.

Multicentre magnetic resonance texture analysis trial using reticulated foam test objects.

Texture analysis in magnetic resonance imaging has the ability to provide useful diagnostic information with respect to the discrimination of disease states of a single tissue or the separation of different tissues. However, for widespread use it is necessary to determine how texture measurements carried out in one center relate to those carried out in another. To this end, a multicentre trial has been performed where reticulated foam test objects have been scanned in six European centers according to a fixed protocol.

The use of reticulated foam in texture test objects for magnetic resonance imaging.

The use of texture analysis in magnetic resonance imaging requires the availability of texture test objects for use in standardisation of in vivo measurement. A series of such objects of varying texture has been developed using reticulated foam, which has an open pore structure. The texture properties of these foams have been compared with in vivo brain and the ability of texture analysis to discriminate the different porosities of foam and brain (white matter) demonstrated.

Palliation of pain associated with metastatic bone cancer using samarium-153 lexidronam: a double-blind placebo-controlled clinical trial.

Purpose: To evaluate the effectiveness and safety of samarium-153 (153Sm) lexidronam (EDTMP) in a double-blind, placebo-controlled study.

Patients And Methods: Patients with painful bone metastases secondary to a variety of primary malignancies were randomized to receive 153Sm-EDTMP 0.5 or 1.

A numerical model of an intensive care ventilator-humidifier system.

Current intensive care ventilator-humidifier systems neither monitor nor adequately control inspired gas humidity. Problems of low delivered humidity and condensation within ventilator circuitry are commonly encountered. To help to address these problems, a numerical model of a complete ventilator-humidifier-patient intensive care system has been developed.

MR image texture analysis--an approach to tissue characterization.

The role and value of texture analysis in the quantification of medical images is reviewed and the various methods described. The promise in magnetic resonance imaging is discussed and the coordinated research programme being carried out within the framework of the European Economic Community Concerted Action on Tissue Characterization by MRS and MRI is outlined. Tissue characterization of the human brain has been performed by texture analysis of proton relaxation time images using a standard MR whole body imager operating at 1.

Trial of modifications to Eurospin MRI test objects.

The original design of the Eurospin test objects (Magn. Reson. Imaging 6:195-199; 1988) for the assessment of magnetic resonance imaging (MRI) image quality, was subjected to re-evaluation at several meetings during the subsequent years, culminating in some changes to the designs.

Performance assessment and quality control in MRI by Eurospin test objects and protocols.

As part of its work, the European Concerted Action "Tissue Characterisation by MRS and MRI" (COMAC-BME) has expended considerable effort in the field of magnetic resonance imaging (MRI) quality control. A set of test objects--the Eurospin set--have been designed and rigorously tested in many systems throughout Europe. The full history of this development is described, together with a detailed presentation of the types of measurements that are achievable with such test objects and examples of the results.

A test material for tissue characterisation and system calibration in MRI.

A tissue-equivalent test material for MRI has been produced from a polysaccharide gel, agarose, containing gadolinium chloride chelated to EDTA. By varying the amounts of each constituent, the T1 and T2 of the material can be varied independently. As a result, the entire range of in vivo tissue relaxation times can be covered.

Quantitative magnetic resonance imaging in assessment of the blood-retinal barrier.

Application of magnetic resonance imaging (MRI) in two-dimensional quantitative assessment of blood-retinal barrier dysfunction was investigated in rabbits using a 0.1 T (4.25 MHz) resistive system.

Preparation of agarose gels as reference substances for NMR relaxation time measurement. EEC Concerted Action Program.

A standard method has been developed for the production of reference materials for NMR relaxation time measurement. These are based on agarose gels doped with gadolinium. The reproducibility and temporal stability of the gels have been found to be excellent.

Multi-center trial with protocols and prototype test objects for the assessment of MRI equipment. EEC Concerted Research Project.

A trial was carried out in which the protocols and prototype test objects developed under a European Economic Community concerted research project for the assessment of MR imaging equipment were tested in a series of commercial imaging systems situated throughout Europe. In general, many imperfections were discovered in the imaging performance of the scanners and, in particular, the accuracy and precision with which the relaxation times T1 and T2 could be measured from the images were found to be rather disappointing.

Practical aspects of ghosting in resistive nuclear magnetic resonance imaging systems.

The concept of 'ghosting' in NMR images is discussed and it is demonstrated that, among other things, any external modulation of the NMR signal can produce such effects. A simple theoretical model, based on elementary Fourier modulation theory is presented for saturation recovery imaging sequences. Both amplitude (AM) and frequency (FM) modulations are considered.

Principles of nuclear magnetic resonance (NMR)--current state of the art.

Nuclear magnetic resonance (NMR) imaging has progressed rapidly from laboratory curiosity to commercial exploitation and clinical application in the space of only three years. The physical principles underlying the technique are described and the equipment requirements outlined. The question of optimal magnetic field strength is discussed.