introduction:  image  distortion  is  one  of  the  major  problems  of  magnetic  resonance  imaging  (mri) for use in 3dmri, velocity mri, fmri and radiotherapy treatment planning (rttp). it is  widely known that the most obvious effect of the inhomogenity of the magnetic fields and the  nonlinearity  of  the  gradient  is  the  geometric  distortion  of  mr  tomograms.  in  this  study,  the...

Background: In this study the basic radiation properties of N-isopropylacrylamaide polymer gel dosimeter were determined together with verification of its soft tissue equivalency. Materials and Methods: The NIPAM gel was prepared and irradiated approximately 2 h after manufacturing. The magnetic resonance (MR) images were made 24 h after irradiation. The nuclear magnetic resonance (NMR) respons...

Patients with pacemakers and implantable cardioverter defibrillators (ICDs) have been commonly withheld from magnetic resonance imaging (MRI) procedures because of magnetic resonance (MR) safety concerns. In response to this clinical need, MR-conditional pacemakers and ICDs have been developed to allow these patients access to MRI. The potential interactions between MRI and recently developed M...

Background: Gliomas are the most common primary neoplasms of the central nervous system. Relative cerebral blood volume (rCBV) could estimate high-grade Gliomas computed with dynamic susceptibility contrast MR imaging which it is artificially lowered by contrast extravasation through a disrupted blood-brain barrier. Objectives: Our intent was to clarify the usefulness of diffusion-weighted m...

Introduction: Internal derangement (ID) of TMJ is the most common type of temporomandibular disorders after muscle disorders and includes all disorders related to incoordination and dislocation of disc and condyle. Anterior disc displacement without reduction or closed lock will happen if the disc or condyle displaces severely or if the disc traps in the space in front of the condyle accompanie...

In the study we assessed the distortion of 7.0 T magnetic resonance (MR) images in reference to 1.5 T MR images in the radiosurgery of metastatic brain tumors. Radiosurgery with Gamma Knife Perfexion was performed for the treatment of a 54-yr-old female patient with multiple brain metastases by the co-registered images of the 7.0 T and 1.5 T magnetic resonance images (MRI). There was no signifi...

OBJECTIVE To describe the spectrum of Magnetic Resonance spectroscopy in focal brain lesions and determine its diagnostic accuracy using histopathology as gold standard in differentiating neoplastic and non-neoplastic focal brain lesions. METHODS The study was conducted in Department of Radiology, Aga Khan University Hospital, Karachi from Dec 2006 till Jan 2009. Fifty three patients found to...

creutzfeldt-jacob disease is a prion disease which has a wide range of clinical presentations. its diagnosis is not simple and clinical manifestation along with eeg, mr imaging findings and cerebrospinal fluid (csf) analysis should be considered for a definite diagnosis. a-50-year-old woman referred with cognitive impairment, myoclonic jerks, mutism and difficulty in swallowing to our clinic. e...

Regularized Estimation of Main and RF Field Inhomogeneity and Longitudinal Relaxation Rate in Magnetic Resonance Imaging by Amanda K. Funai Chair: Jeffrey A. Fessler In designing pulses and algorithms for magnetic resonance imaging, several simplifications to the Bloch equation are used. However, as magnetic resonance (MR) imaging requires higher temporal resolution and faster pulses are used, ...