BACKGROUND AND PURPOSE MR imaging techniques have proved their efficacy in imaging the head and neck region. In this study, we compared T1-weighted, dual T2-weighted, and fat-suppressed MR imaging and unenhanced and contrast-enhanced 3D time-of-flight MR angiography sequences for detection of head and neck paragangliomas. METHODS Thirty-one patients with 70 paragangliomas were examined. Four ...

A novel technique of magnetic resonance (MR) imaging, which combines gradient-echo and spin-echo (GRASE) technique, accomplishes T2-weighted multisection imaging in drastically reduced imaging time, currently 24 times faster than spin-echo imaging. The GRASE technique maintains contrast mechanisms, high spatial resolution, and image quality of spin-echo imaging and is compatible with clinical w...

Intensity normalization is an important preprocessing step in magnetic resonance (MR) image analysis. In MR images (MRI), the observed intensities are primarily dependent on (1) intrinsic magnetic resonance properties of the tissues such as proton density (PD ), longitudinal and transverse relaxation times (T1 and T2 respectively), and (2) the scanner imaging parameters like echo time (TE), rep...

Introduction: Metabolic and structural changes occur in brain tissue within minutes of ischemia. Changes in the relative concentration of oxyand deoxy-hemoglobin, blood volume, and cell microstructure within ischemic tissue may also initiate specific metabolic processes and lead to changes in tissue magnetic susceptibility. The Localization by Adiabatic Selective Refocusing (LASER) MR localizat...

BACKGROUND AND PURPOSE Relative cerebral blood volume (rCBV) accuracy can vary substantially depending on the dynamic susceptibility-weighted contrast-enhanced (DSC) acquisition and postprocessing methods, due to blood-brain barrier disruption and resulting T1-weighted leakage and T2- and/or T2*-weighted imaging (T2/T2*WI) residual effects. We set out to determine optimal DSC conditions that ad...

To compare conventional and fat suppression MR imaging in their ability to detect head and neck lesions, we prospectively studied 17 patients with head and neck tumors and one normal volunteer. Five patients had benign tumors (one mixed cell tumor, one hemangioma, one lipoma, and two plexiform neurofibromas), 10 had malignant tumors (six squamous cell carcinomas, two minor salivary gland carcin...

This report details the CT, MR, and angiography findings of a solitary fibrous tumor involving the larynx of a 34-year-old man. A precontrast CT scan revealed a well-defined isodense mass in the submucosal region of the supraglottic larynx. The tumor appeared as a mixed intensity lesion on the T1- and T2-weighted MR images. A T2-weighted MR image showed a central, round, and low signal intensit...

Using a modification of the partial saturation (PS) pulse sequence, we developed an MR method that permits the acquisition of highly T1and T2-weighted images of the head and body in as little as 10 sec. The PS images, which were acquired at 0.6 T in a series of six patients with acute and subacute hemorrhage, showed a striking reduction in the signal intensity of hemorrhagic lesions. This effec...

Different magnetic resonance imaging pulse sequences are used to generate image contrasts based on physical properties of tissues, which provide different and often complementary information about them. Therefore multiple image contrasts are useful for multimodal analysis of medical images. Often, medical image processing algorithms are optimized for particular image contrasts. If a desirable c...

Background Combined assessment of edema and necrosis using conventional T2-weighted sequences and late gadolinium enhanced (LGE) imaging has been established as the reference standard for in-vivo assessment of myocardial damage in acute myocardial infarction (AMI). However the standard CMR protocol is time-consuming, not tolerated by patients in poor clinical conditions and needs of gadolinium ...