Follow-up of regional myocardial T2 relaxation times in patients with myocardial infarction evaluated with magnetic resonance imaging

1990 ◽  
Vol 11 (2) ◽  
pp. 110-119 ◽  
Author(s):  
X. Hanno Krauss ◽  
Ernst E. van der Wall ◽  
Arnoud van der Laarse ◽  
Joost Doornbos ◽  
Albert de Roos ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Myocardial Infarction ◽  
Magnetic Resonance ◽  
Relaxation Times ◽  
Resonance Imaging ◽  
T2 Relaxation

Evaluation of Relaxation Time Measurements by Magnetic Resonance Imaging

1987 ◽  
Vol 28 (3) ◽  
pp. 345-351 ◽  
Author(s):  
L. Kjær ◽  
C. Thomsen ◽  
O. Henriksen ◽  
P. Ring ◽  
M. Stubgaard ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Relaxation Time ◽  
Magnetic Resonance ◽  
Diffusion Processes ◽  
Relaxation Times ◽  
Gradient Field ◽  
Maximum Deviation ◽  
Resonance Imaging ◽  
T2 Relaxation ◽  
T1 And T2

Several circumstances may explain the great variation in reported proton T1 and T2 relaxation times usually seen. This study was designed to evaluate the accuracy of relaxation time measurements by magnetic resonance imaging (MRI) operating at 1.5 tesla. Using a phantom of nine boxes with different concentrations of CuSO4 and correlating the calculated T1 and T2 values with reference values obtained by two spectrometers (corrected to MRI-proton frequency=64 MHz) we found a maximum deviation of about 10 per cent. Measurements performed on a large water phantom in order to evaluate the homogeneity in the imaging plane showed a variation of less than 10 per cent within 10 cm from the centre of the magnet in all three imaging planes. Changing the gradient field strength apparently had no influence on the T2 values recorded. Consequently diffusion processes seem without significance. It is concluded that proton T1 and T2 relaxation times covering the majority of the biologic range can be measured by MRI with an overall accuracy of 5 to 10 per cent. Quality control studies along the lines indicated in this study are recommended.

Age dependency of cartilage magnetic resonance imaging T2 relaxation times in asymptomatic women

2004 ◽  
Vol 50 (9) ◽  
pp. 2820-2828 ◽  
Author(s):  
Timothy J. Mosher ◽  
Yi Liu ◽  
Qing X. Yang ◽  
Jing Yao ◽  
Ryan Smith ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Relaxation Times ◽  
Age Dependency ◽  
Resonance Imaging ◽  
T2 Relaxation ◽  
Asymptomatic Women

PRIMARY MALIGNANT MELANOMA OF THE CEREBELLOPONTINE ANGLE

Neurosurgery ◽  
2006 ◽  
Vol 59 (6) ◽  
pp. E1336-E1336 ◽  
Author(s):  
Chima O. Oluigbo ◽  
Stephen R. Cooke ◽  
Peter A. Flynn ◽  
Kishor A. Choudhari
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Malignant Melanoma ◽  
Cerebellopontine Angle ◽  
Clinical Presentation ◽  
Relaxation Times ◽  
Primary Malignant Melanoma ◽  
Resonance Imaging ◽  
T2 Relaxation ◽  
T1 And T2

Abstract OBJECTIVE To present a rare case of a primary malignant melanoma of the central nervous system presenting as a cerebellopontine angle (CPA) tumor and to delineate aspects of the clinical presentation and magnetic resonance imaging scan characteristics that may suggest this unusual condition. CLINICAL PRESENTATION The clinical presentation consisted of a short duration of right-sided sensorineural hearing loss, facial weakness, and ataxia in a previously healthy man. Brain magnetic resonance imaging scans showed a right-sided CPA tumor exhibiting shortening of T1 and T2 relaxation times, but overall neuroradiological features were not consistent with any commonly occurring CPA tumors. INTERVENTION Gross total excision of the lesion was accomplished via a right suboccipital craniectomy. Histological examination revealed a malignant melanoma. A detailed search excluded extracranial primary melanoma. CONCLUSION Correlation of clinical and imaging findings offer the most important clues in the diagnosis of such unusual primary malignant tumors of the CPA. A history of rapid onset of audiovestibular symptoms, presence of facial palsy, and shortening of T1 and T2 relaxation times on magnetic resonance imaging scans should arouse the clinician's suspicions.

scholarly journals Evaluation of patients with acute myocardial infarction by magnetic resonance imaging: A mid term follow-up

1996 ◽  
Vol 27 (2) ◽  
pp. 269-270
Author(s):  
Ibraim Pinto ◽  
Ricardo Pavanello ◽  
Rodrigo Barretto ◽  
Alexandre Abizaid ◽  
Leopoldo Piegas ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Magnetic Resonance ◽  
Resonance Imaging

scholarly journals Method for Imaging the States of Water by Nuclear Magnetic Resonance in Low-water-containing Apple Bud and Stem Tissues

1993 ◽  
Vol 118 (5) ◽  
pp. 628-631 ◽  
Author(s):  
Merle M. Millard ◽  
Dehua Liu ◽  
Michael J. Line ◽  
Miklos Faust
Keyword(s):  
Magnetic Resonance Imaging ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Malus Domestica ◽  
Woody Plants ◽  
Relaxation Times ◽  
Tissue Type ◽  
Proton Density ◽  
Resonance Imaging ◽  
T2 Relaxation

Magnetic resonance imaging estimates unreasonably high T2 times when creating T2 images in woody plants when tissues contain a limited amount of water. We developed a system to correct such images. Tissue distribution of proton density and states of water were determined by creating images of proton density and T2 relaxation times in summerdormant (paradormant) apple (Malus domestica Borkh.) buds. These images reveal that the proton density and water states obviously are not distributed uniformly in the bud and stem; but, the distribution of water depends greatly on the tissue type (bark, xylem, or meristem of the stem), and there are differences in the states of water even within the same tissue. At low proton density T2, calculated relaxation times were unreasonably high in tissues, with the exception of meristem of the shoot. In buds that were induced to grow and in which proton density was higher, T2 times appeared as expected. Variance of T2 times in tissues containing little water was 50 times higher than in those with a higher water content. Data with such high variance were excluded from the images; thus, the image was “corrected.” Corrected images of T2 times fit the distribution of water indicated by the proton density images well.

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