Biomedical subjects

T Spraggins

Publications and source records attributed to T Spraggins.

3 recordsLinked to original sources

PubMed1999

MRI changes during water loading in patients with polydipsia and intermittent hyponatremia.

OBJECTIVE: Patients with polydipsia and intermittent hyponatremia have greater ventricle-brain ratios (VBRs) than matched patients without polydipsia and intermittent hyponatremia and normal subjects. Unlike previous studies, this study controlled for the impact of water loading when examining the volume of intracranial structures. METHOD: Under controlled conditions, eight male schizophrenic patients with polydipsia and intermittent hyponatremia were first assigned to either normal fluid intake or oral water loading and then the alternative condition the following day. Magnetic resonance imaging (MRI) volumetric measurements were made with the use of a standardized protocol. RESULTS: During water loading, total VBR and lateral ventricle volume significantly decreased by 13.1% and 12.6%, respectively. A strong association between change in serum sodium concentration and change in VBR was noted across conditions. CONCLUSIONS: These findings indicate that 1) water loading does not account for the diminished brain volume observed in patients with polydipsia and intermittent hyponatremia in previous studies, and 2) hyponatremia can significantly alter brain morphology on MRI.

Adult↗

PubMed1988

SLIM: spectral localization by imaging.

Nonspectroscopic magnetic resonance (MR) imaging often shows that a slice is composed of several compartments, each of which can be assumed to have a spatially homogeneous magnetic resonance spectrum, e.g., a limb composed of fat, muscle, bone marrow, and tumor. We show how to use structural information from such a nonspectroscopic image in order to increase the efficiency of subsequent localized spectroscopic measurements. Specifically, knowledge of the boundaries of N compartments makes it possible to reconstruct compartmental spectra from spectroscopic signals from an entire cross section with N or more different degrees of phase encoding. Experimental studies of a two-compartment phantom show that this method (SLIM) can be used to derive regional hydrogen spectra of a single slice from signals with as few as 2 phase-encoding steps, although Fourier transform chemical-shift imaging requires 64 steps to achieve a result of comparable accuracy. SLIM required only 16 phase-encoding steps to obtain accurate regional single slice spectra in a human limb with three compartments. Spectra of similar quality, obtained by Fourier transform chemical-shift imaging, required 256 to 1024 steps.

Humans↗

PubMed1987

Musculoskeletal tumors: improved depiction with linear combinations of MR images.

With postprocessing, the authors produced a single hybrid image that combines the complementary information in conventional T1- and T2-weighted magnetic resonance (MR) images. A 1-T MR imager was used to produce T1- and T2-weighted images (repetition time, msec/echo time, msec: 500/30, 1,500/120) of patients with various primary bone tumors. Various weighted sums and differences of these images were then formed. Weighted subtraction allowed formation of hybrid images with high contrast between tumor and all adjacent normal tissues (muscle, fat, bone marrow), unlike the original T1- and T2-weighted images. Certain weighted sums of the acquired images simultaneously display the high signal-to-noise and clear anatomic detail of the T1-weighted technique along with the high contrast between extraosseous tumor and muscle of the T2-weighted image. A single hybrid MR image can contain useful characteristics both of T1- and T2-weighted images, making it easier for one to detect the extent of an abnormality.

Bone Neoplasms↗