Combined17O/1H MRI study in a whole-body scanner

PurposeTo evaluate posterior eye shape variations across a wide refractive error range using brain MRI in a multiethnic cohort.MethodsAdult subjects in the multiethnic Singapore Epidemiology of Eye Disease study were included. Spherical equivalent (SE) was measured using subjective refraction, and axial length (AL) was measured using optical biometry. MRI was performed using a 3-Tesla whole body scanner with a 32-channel head coil. The radii and asphericity based on fitting of the posterior two-thirds of the eye (240°) were calculated. The refractive error status was categorised as myopic (SE<−0.5 D) or non-myopic (SE≥−0.5 D).ResultsA total of 450 adult participants (mean age 64.2±6.5 years old) were included. Less oblate asphericity was associated with more myopic SE, longer AL and with a refractive error categorisation of myopia (p<0.001 for all). Asphericity values were less oblate in myopic compared with non-myopic eyes (p<0.001). Multivariate analysis showed that Chinese subjects had less oblate eyes than Malay and Indian subjects, especially in non-myopic eyes.ConclusionsA less oblate posterior eye shape was associated with myopic eyes. Chinese eyes have less oblate shapes than Malay and Indian eyes, especially in non-myopic eyes.

Download Full-text

A preliminary investigation of radiation dose reduction on an EMI CT5005 whole body scanner using a copper wedge

British Journal of Radiology ◽

10.1259/0007-1285-55-657-634 ◽

1982 ◽

Vol 55 (657) ◽

pp. 634-639 ◽

Cited By ~ 3

Author(s):

J. A. C. Webb ◽

K. Cranley ◽

T. K. Bell

Keyword(s):

Radiation Dose ◽

Dose Reduction ◽

Preliminary Investigation ◽

Radiation Dose Reduction ◽

Whole Body ◽

Body Scanner

Download Full-text

Applications of specialized coils for high-resolution MRI on a whole-body scanner

Magnetic Resonance Materials in Physics Biology and Medicine ◽

10.1007/bf01759777 ◽

1996 ◽

Vol 4 (1) ◽

pp. 27-33 ◽

Cited By ~ 8

Author(s):

Jürgen Mäurer ◽

Herman Requardt ◽

Bernhard Sander ◽

Friedrich D. Knollmann ◽

Arne-jörn Lemke ◽

...

Keyword(s):

High Resolution ◽

Whole Body ◽

High Resolution Mri ◽

Body Scanner

Download Full-text

Neuronal pH Regulation: Constant Normal Intracellular pH is Maintained in Brain during Low Extracellular pH Induced by Acetazolamide—31P NMR Study

Journal of Cerebral Blood Flow & Metabolism ◽

10.1038/jcbfm.1989.61 ◽

1989 ◽

Vol 9 (3) ◽

pp. 417-421 ◽

Cited By ~ 48

Author(s):

Sissel Vorstrup ◽

Karl Erik Jensen ◽

Carsten Thomsen ◽

Ole Henriksen ◽

Niels A. Lassen ◽

...

Keyword(s):

Intracellular Ph ◽

Ph Regulation ◽

Extracellular Ph ◽

Whole Body ◽

Resonance Spectroscopy ◽

Nmr Study ◽

Resonance Frequencies ◽

The Mean ◽

Ph Decrease ◽

Body Scanner

The intracellular pH in the brain was studied in six healthy volunteers before and immediately after the administration of 2 g of acetazolamide. Phosphorus-31 nuclear magnetic resonance spectroscopy by a 1.5 tesla whole-body scanner was used. The chemical shift between the inorganic phosphate and the phosphocreatine resonance frequencies was used for indirect assessment of the intracellular pH. The mean baseline intracellular pH was 7.05 ± 0.04 (SD). The mean pH changes obtained at 15-min intervals within the first hour of acetazolamide administration were −0.03 ± 0.04 (SD), −0.02 ± 0.03 (SD), and 0.00 ± 0.04 (SD), i.e., no statistically significant pH decrease was observed during the period where extracellular pH is known to drop markedly. Although several factors contribute to the lack of change of the intraneuronal pH, we will discuss that this observation in addition might suggest a direct intracerebral effect of acetazolamide.

Download Full-text