Recent MRS studies have indicated that a higher body mass index (BMI) is associated with lower brain metabolite levels. Generally, individuals with higher BMIs have more body fat deposits than individuals with normal BMIs. This single-voxel spectroscopy (SVS) study investigated possible effects of fat on MR-measured metabolite signal areas, which may at least partly explain the observed associa...

OBJECTIVE Phantoms with simulating mandibular trabecular bone structure fabricated using micro-stereolithography were applied for a quantitative evaluation of cone-beam computed tomography (CT) images. MATERIALS AND METHODS Phantoms with a three-dimensional lattice, in which a square pillar was set at 0.10, 0.20, 0.30 and 0.40 mm at the edge, spaced at 0.60 mm, were made of an acrylic resin u...

In vivo magnetic resonance spectroscopic imaging of the prostate using single-voxel and multivoxel two-dimensional (2D) J-resolved sequences is investigated at a main magnetic field strength of 3 T. Citrate, an important metabolite often used to aid the detection of prostate cancer in magnetic resonance spectroscopic exams, can be reliably detected along with the other metabolites using this me...

INTRODUCTION The field inhomogeneity mapped using MRI offers the opportunity to characterize tissue magnetic susceptibility. The field measured in a voxel is a dipole kernel convolution of all tissue susceptibility sources surrounding the voxel [1]. The zero cone surfaces of the dipole kernel in Fourier domain undersamples the measured field, causing illposedness for the inverse problem of deri...

A method for quantitative assessment of tree structures is reported allowing evaluation of airway or vascular tree morphology and its associated function. Our skeletonization and branch-point identification method provides a basis for tree quantification or tree matching, tree-branch diameter measurement in any orientation, and labeling individual branch segments. All main components of our met...

Introduction Constant-time point-resolved spectroscopy (CT-PRESS) [1] is a single voxel technique that simplifies the spectral pattern and permits the detection of Jcoupled resonances with high signal-to-noise ratio by using effective homonuclear decoupling [2]. The technique relies on non-selective refocusing, i.e., effective homonuclear decoupling is only achieved if the RF pulses refocus all...

Electric current-induced phase alternations have been imaged by fast magnetic resonance image (MRI) technology. We measured the magnetic resonance phase images induced by pulsed current stimulation from a phantom and detected its sensitivity. The pulsed current-induced phase image demonstrated the feasibility to detect phase changes of the proton magnetic resonance signal that could mimic neuro...

PURPOSE Presence of photon attenuation severely challenges quantitative accuracy in single-photon emission computed tomography (SPECT) imaging. Subsequently, various attenuation correction methods have been developed to compensate for this degradation. The present study aims to implement an attenuation correction method and then to evaluate quantification accuracy of attenuation correction in s...

The purpose of this work was to extend the verification of Monte Carlo based methods for estimating radiation dose in computed tomography (CT) exams beyond a single CT scanner to a multidetector CT (MDCT) scanner, and from cylindrical CTDI phantom measurements to both cylindrical and physical anthropomorphic phantoms. Both cylindrical and physical anthropomorphic phantoms were scanned on an MDC...

Image segmentation plays an important role in medical image processing. The aim of conventional hard segmentation methods is to assign a unique label to each voxel. However, due to the limited spatial resolution of medical imaging equipment and the complex anatomic structure of soft tissues, a single voxel in a medical image may be composed of several tissue types, which is called partial volum...