Background Cardiac diffusion tensor imaging (cDTI) by cardiovascular magnetic resonance is becoming more robust for clinical imaging. It has the potential to assess microstructural changes, such as disarray in hypertrophic cardiomyopathy, through measures of fractional anisotropy (FA) and mean diffusivity (MD).[1] However, normal variation in regional and transmural FA and MD is not well descri...

background: iodine brachytherapy sources with low photon energies have been widely used in treating cancerous tumors. dosimetric parameters of brachytherapy sources should be determined according to aapm tg-43u1 recommendations before clinical use. monte carlo codes are reliable tools in calculation of these parameters for brachytherapy sources. materials and methods: dosimetric parameters (dos...

Whistler waves are often observed in magnetopause reconnection associated with electron beams. We analyze seven MMS crossings surrounding the diffusion region (EDR) to study role of beams whistler excitation. Waves have two major types: (a) Narrow-band high ellipticities and (b) broad-band that more electrostatic significant variations wave normal angles. While both types beams, key difference ...

BACKGROUND AND PURPOSE The spinal cord is a site of predilection for MS lesions. While diffusion tensor imaging is useful for the study of anisotropic systems such as WM tracts, it is of more limited utility in tissues with more isotropic microstructures (on the length scales studied with diffusion MR imaging) such as gray matter. In contrast, diffusional kurtosis imaging, which measures both G...

BACKGROUND Diffusion-tensor (DT) magnetic resonance imaging (MRI) has the potential to elucidate some characteristics of tissue microstructure inaccessible to other MRI techniques. OBJECTIVE To investigate whether normal-appearing brain tissue abnormalities occur in patients with multiple sclerosis at the earliest clinical stage and whether their severity is predictive of a short-term disease...

Background: Presurigical planning for glioma tumor resection and radiotherapy treatment require proper delineation of tumoral and peritumoral areas of brain. Diffusion tensor imaging (DTI) is the most common mathematical model applied for diffusion weighted MRI data. Neurite orientation dispersion and density imaging (NODDI) is another mathematical model for DWI data modeling.Objective: We stud...

Department of Radiology, College of Medicine, Dong-A University, Busan, Korea Received July 8, 2009 ; Accepted August 4, 2009 Address reprint requests to : Sunseob Choi, M.D., Department of Radiology, Dong-A University Medical Center, 1,3-ga, Dongdaeshin-dong, Seo-gu, Busan 602-715, Korea. Tel. 82-51-240-5344 Fax. 82-51-253-4931 E-mail: [email protected] Purpose: This study was designed to ...

Abstract In the present work, we investigated influence of high hydrostatic pressure up to 11 kbar on conductivity in basal ab-plane medium-doped with praseodymium ( x ≈0.23) single-crystal Y 1-x Pr Ba 2 Cu 3 O 7-δ samples. It was determined that, contrast pure YBa samples optimal oxygen content, application leads formation phase separation plane 0.77 0.23 single crystals. Possible mechanisms e...

PURPOSE The mean intercept length tensor is the most used technique to estimate microstructure orientation and anisotropy of trabecular bone. This paper proposes an efficient extension of this technique to gray-scale images based on a closed formulation of the mean intercept length tensor and a generalization using different angular convolution kernels. METHODS First, the extended Gaussian im...

We present a comprehensive fully vectorial model for the cavity eigenmodes of oxide-cofined vertical-cavity surface-emitting lasers (VCSELs) with the details of their complex structure. It includes device-inherent symmetry-breaking mechanisms like noncircular geometries and material anisotropies related to the elasto-optic and electro-optic effect. The latter is accounted for in the model start...