Skeletal muscular relaxation time from postmortem MR imaging of adult humans

2020 ◽  
Vol 22 ◽  
pp. 200399
Author(s):  
Kazuya Tashiro ◽  
Tomoya Kobayashi ◽  
Seiji Shiotani ◽  
Hajime Saitou ◽  
Kazunori Kaga ◽  
...  
Keyword(s):  
Relaxation Time ◽  
Mr Imaging ◽  
Muscular Relaxation ◽  
Adult Humans

scholarly journals T2 Relaxation Time of Cartilage at MR Imaging: Comparison with Severity of Knee Osteoarthritis

Radiology ◽  
2004 ◽  
Vol 232 (2) ◽  
pp. 592-598 ◽  
Author(s):  
Timothy C. Dunn ◽  
Ying Lu ◽  
Hua Jin ◽  
Michael D. Ries ◽  
Sharmila Majumdar
Keyword(s):  
Relaxation Time ◽  
Mr Imaging ◽  
Knee Osteoarthritis ◽  
T2 Relaxation Time ◽  
T2 Relaxation

Proton MR Spectroscopy and MR Imaging in Acute and Chronic Multiple Sclerosis — Ringlike Appearances in Acute Plaques

1996 ◽  
Vol 37 (1P1) ◽  
pp. 278-287 ◽  
Author(s):  
A.-M. Landtblom ◽  
L. Sjöqvist ◽  
B. Söderfeldt ◽  
H. Nyland ◽  
K.-Å. Thuomas
Keyword(s):  
Multiple Sclerosis ◽  
Relaxation Time ◽  
Mr Imaging ◽  
Brain Lesions ◽  
T2 Relaxation Time ◽  
Healthy Individuals ◽  
T2 Relaxation ◽  
Proton Mrs ◽  
Proton Mr Spectroscopy ◽  
The Core

Purpose: We wanted to compare the metabolite status of brain lesions in different clinical subtypes of multiple sclerosis (MS). Two acute MS lesions with ringlike appearances were also investigated. Material and Methods: Twenty-three clinically stable MS patients, 2 patients with acute relapses, and 15 healthy individuals were examined by MR imaging and localized proton MRS. Results: No metabolite differences were seen in plaques of different subtypes. Decreased NAA/Cr and NAA/choline ratios as well as increased inositol/Cr ratios were observed in the plaques of the clinically stable or chronic active MS patients as compared with controls. The ring plaques had hyperintense cores with surrounding halos, separated from the cores by rings with low signal intensity in T2-weighted images. The core exhibited a prolonged T2 relaxation time. Proton spectra initially contained lactate. Conclusion: No differences between the metabolite status of nonacute plaques in different clinical subtypes could be detected. The ring plaques contained lactate signals indicating oedema, inflammation, and macrophage invasion, and may be transition forms between acute oedematous lesions and chronic demyelinated plaques.

Proton Tl Relaxation Time of Normal and Abnormal Urine

1987 ◽  
Vol 28 (5) ◽  
pp. 601-602
Author(s):  
A. Alanen ◽  
P. Nummi ◽  
M. Kormano ◽  
K. Irjala
Keyword(s):  
Relaxation Time ◽  
Mr Imaging ◽  
Contrast Medium ◽  
Relaxation Times ◽  
Urine Samples ◽  
Medium Ph ◽  
T1 Relaxation ◽  
Radiographic Contrast Medium ◽  
Radiographic Contrast

Relaxation times Tl of normal and abnormal urine samples were measured with a 0.02 tesla MRI device in a spectrometric mode. Protein containing urine from patients with glomerulonephritis showed a slight shortening of Tl relaxation time. Radiographic contrast medium, pH, osmolality or glucose in diabetes did not significantly change the Tl relaxation time of urine. Urine can be used as a T1 relaxation reference in MR imaging of the pelvis even if the patient has received radiographic contrast medium or has diabetes or proteinuria for any reason.

scholarly journals Effect of Mineral Composition on Transverse Relaxation Time Distributions and MR Imaging of Tight Rocks from Offshore Ireland

Minerals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 232
Author(s):  
Stian Almenningen ◽  
Srikumar Roy ◽  
Arif Hussain ◽  
John Georg Seland ◽  
Geir Ersland
Keyword(s):  
Magnetic Field ◽  
Relaxation Time ◽  
Mr Imaging ◽  
Field Strength ◽  
High Field ◽  
Transverse Relaxation Time ◽  
Transverse Relaxation ◽  
The Core ◽  
Low Field ◽  
Field Strengths

In this paper, we investigate the effect of magnetic field strength on the transverse relaxation time constant (T2) in six distinct core plugs from four different rock types (three sandstones, one basalt, one volcanic tuff and one siltstone), retrieved from offshore Ireland. The CPMG pulse-sequence was used at two different magnetic field strengths: high-field at 4.70 T and low-field at 0.28 T. Axial images of the core plugs were also acquired with the RAREst sequence at high magnetic field strength. Thin-sections of the core plugs were prepared for optical imaging and SEM analysis, and provided qualitative information on the porosity and quantification of the elemental composition of the rock material. The content of iron varied from 4 wt. % to close to zero in the rock samples. Nevertheless, the effective T2 distributions obtained at low-field were used to successfully predict the porosity of the core plugs. Severe signal attenuations from internal magnetic gradients resulted in an underestimation of the porosity at high-field. No definitive trend was identified on the evolution of discrete relaxation time components between magnetic field strengths. The low-field measurements demonstrate that NMR is a powerful quantitative tool for petrophysical rock analysis as compared to thin-section analysis. The results of this study are of interest to the research community who characterizes natural gas hydrates in tight heterogeneous core plugs, and who typically relies on MR imaging to distinguish between solid hydrates and fluid phases. It further exemplifies the importance of selecting appropriate magnetic field strengths when employing NMR/MRI for porosity calculation in tight rock.

MR Imaging of Patellar Cartilage Degeneration at 0.02 T

1991 ◽  
Vol 32 (6) ◽  
pp. 514-517 ◽  
Author(s):  
S. K. Koskinen ◽  
M. Komu ◽  
H. J. Aho ◽  
M. Kormano
Keyword(s):  
Relaxation Time ◽  
Chemical Shift ◽  
Mr Imaging ◽  
Cartilage Damage ◽  
Relaxation Times ◽  
Cartilage Degeneration ◽  
Water Proton ◽  
T2 Relaxation ◽  
Water Separation ◽  
Patellar Cartilage

MR imaging with a 0.02 T resistive magnet was used to establish the correlation between the histologic grading of patellar cartilage degeneration and fat water separation images or T1- and T2-relaxation times. We examined 23 cadaveric patellae. There was a positive correlation between histologically graded cartilage degeneration and T1-relaxation time. Patellar cartilage was well differentiated from surrounding structures on chemical shift water proton images, and an evaluation of cartilage degeneration was possible. No correlation was found between cartilage damage and T2-relaxation time. Chemical shift imaging at 0.02 T is easy to perform and gives further information of cartilage disorders.

scholarly journals Hepatic Relaxation Times from Postmortem MR Imaging of Adult Humans

2016 ◽  
Vol 15 (3) ◽  
pp. 281-287 ◽  
Author(s):  
Seiji SHIOTANI ◽  
Tomoya KOBAYASHI ◽  
Hideyuki HAYAKAWA ◽  
Kazuhiro HOMMA ◽  
Harumi SAKAHARA
Keyword(s):  
Mr Imaging ◽  
Relaxation Times ◽  
Adult Humans
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