OBJECTIVES Manganese exposure leads to diffuse cerebral metal deposition with the highest concentration in the globus pallidus associated with increased T1-weighted MRI signal. T1 signal intensity in extra-pallidal basal ganglia (caudate and putamen) has not been studied in occupationally exposed workers. Diffusion weighted imaging is a non-invasive measure of neuronal damage and may provide a ...

We propose a new MAP-based technique for the unsupervised segmentation of different brain structures (white matter, gray matter, etc.) from T1-weighted MR brain images. In this paper, we follow a procedure like most conventional approaches, in which T1-weighted MR brain images and desired maps of regions (white matter, gray matter, etc.) are modeled by a joint Markov-Gibbs Random Field model (M...

OBJECTIVE To determine imaging features that may separate adamantinomatous and papillary variants of craniopharyngiomas given that tumors with adamantinomatous signature features are associated with higher recurrence rates, morbidity, and mortality. We specifically reviewed calcification on CT, T1 bright signal intensity, and cystic change on T2 weighted images for differentiating these two typ...

CT and MR imaging showed basal ganglia calcification that appeared as high signal intensity on T1-weighted images of a patient with pseudohypoparathyroidism. MR imaging of an experimental model of calcium phosphate suspensions showed a signal similar to that seen in the patient. Additionally, T1 and T2 relaxation times of the solutions were measured and showed decreases in both parameters with ...

PURPOSE To determine whether the bony and soft-tissue obliterations of the intralabyrinthine fluid spaces reported in pathologic studies of patients with Cogan syndrome can be detected with MR or CT. METHODS The inner ears of six patients with Cogan syndrome were studied. High-resolution CT was performed in five patients; all six patients were studied with MR, including T1-weighted spin-echo ...

Imaging in Neurocysticercosis Neurocysticercosis (NCC) is a common cause of morbidity in many developing countries and a common cause of seizure disorder in children and adults. The 4 stages of NCC are vesicular, vesicular colloidal, granular nodular, and nodular calcified. The appearance on MR imaging would depend on the stage of the disease. Most commonly, NCC presents as isohypointense lesio...

In bolus-tracking MRI, a bolus of paramagnetic tracer is injected intravenously, and the signal changes induced by the tracer are measured in an organ-of-interest using a fast dynamic imaging sequence [1]. The objective is to measure hemodynamic properties of body tissue. For this purpose, two signal-time curves must be measured: one inside the feeding artery (the arterial input function AIF), ...

T1-weighted contrast MRI with prepolarization was detected with a superconducting quantum interference device (SQUID). A spin evolution period in a variable field between prepolarization and detection enabled the measurement of T1 in fields between 1.7 T and 300 mT; T1 dispersion curves of agarose gel samples over five decades in frequency were obtained. SQUID detection at 5.6 kHz drastically r...

Previous studies suggested that magnetization transfer ratio (MTR) histograms are highly correlated with other magnetic resonance imaging (MRI) measures and can be used as a reliable method for quantifying overall disease burden in multiple sclerosis (MS). However, the relative influence of burden and severity of macroscopic MS lesions and degree of brain atrophy on various MTR histogram parame...

BACKGROUND AND PURPOSE The T1-weighted fast spin-echo (T1-FSE) MR imaging sequence is not used routinely, since the speed advantage is not as dramatic as it is in T2-weighted imaging. We evaluated the T1-FSE sequence to determine whether this technique can replace the conventional T1-weighted spin-echo (T1-SE) sequence for routine contrast-enhanced imaging. METHODS Sixty-nine patients with in...