Introduction Proton (1H) MR Spectroscopy (MRS) of the breast cancer has been reported to be useful for the diagnosis and the assessment of treatment response to chemotherapy (1). In most reports, MRS was obtained after dynamic contrast-enhanced MRI, since voxel of interest (VOI) for MRS could be located easily referring to contrast-enhanced MRI. However there are some reports that MRS was affec...

Introduction The in vivo lung morphometry technique, relying on measuring Brownian motion of inhaled hyperpolarized gas in lung airspaces, makes it possible to obtain in vivo information on lung microstructure at the alveolar level [1-3]. This communication presents a theoretical background and experimental method for a new approach to study lung microstructure, that is based on T2*-relaxation ...

BACKGROUND AND PURPOSE Spontaneous echocardiographic contrast (SEC) is correlated to clinical thromboembolic events. We sought to determine the origin of SEC by utilizing direct analysis of left atrial blood. METHODS We examined the blood of 13 patients with and 19 without SEC. Blood samples were taken from the femoral vein and artery and from the right and left atria after transseptal punctu...

Recently reported contrast in phase images of human and animal brains obtained with gradient-recalled echo MRI holds great promise for the in vivo study of biological tissue structure with substantially improved resolution. Herein we investigate the origins of this contrast and demonstrate that it depends on the tissue "magnetic architecture" at the subcellular and cellular levels. This archite...

Introduction There has been increasing interest in using micron-sized iron oxide (MPIO) particles for cell tracking[1]. Traditionally, T2* weighted images have been used to provide negative contrast; however hypointense regions that are not due to iron oxide particles are likely to be present in biological samples. Positive contrast techniques have been shown to be more specific to contrast gen...

Introduction To characterize microvasculature, one can perform a DCE-MRI experiment (a first injection of contrast agent (CA) to estimate the vessel wall permeability) followed by a DSC-MRI experiment (a second injection of CA to estimate relative blood volume (rCBV), relative blood flow, etc.) [1]. The DSC experiment can even yield information on vessel size if a gradient echo and a spin echo ...

BACKGROUND AND PURPOSE Spontaneous echo contrast (SEC) is thought to represent a risk factor for cardioembolic stroke. In vitro studies suggest that SEC results from interaction between red cells and fibrinogen. To better understand the relation between SEC and stroke and to investigate the in vivo genesis of SEC, we examined the relation between SEC, the constituents of the blood, and plasma a...

Recent studies have shown that there is a direct link between the orientation of the nerve fibers in white matter (WM) and the contrast observed in magnitude and phase images acquired using gradient echo MRI. Understanding the origin of this link is of great interest because it could offer access to a new diagnostic tool for investigating tissue microstructure. Since it has been suggested that ...

PURPOSE A T1-weighted multishot inversion-recovery (IR) echo-planar MR imaging (EPI) sequence was developed to improve intracranial tissue differentiation; its diagnostic utility was compared with that of conventional axial T1-weighted spin-echo and axial T2-weighted turbo spin-echo sequences. METHODS Eighteen patients with known or suspected primary or metastatic brain neoplasia were imaged ...