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.

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.

T1 and T2 relaxation times in schizophrenia as measured with magnetic resonance imaging

1991 ◽  
Vol 5 (3) ◽  
pp. 223-232 ◽  
Author(s):  
Nancy C. Andreasen ◽  
J.C. Ehrhardt ◽  
Victor W. Swayze ◽  
Gary Tyrell ◽  
Gregg Cohen ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Relaxation Times ◽  
Resonance Imaging ◽  
T2 Relaxation ◽  
T1 And T2

scholarly journals P010 Measurement of colonic mucosal content of biologics with the use of magnetic resonance imaging (MRI): A pilot study in patients with ulcerative colitis

2020 ◽  
Vol 14 (Supplement_1) ◽  
pp. S134-S135
Author(s):  
R Filip ◽  
P Bar ◽  
D Bartusik-Aebisher ◽  
D Aebisher
Keyword(s):  
Magnetic Resonance Imaging ◽  
Ulcerative Colitis ◽  
Pilot Study ◽  
Magnetic Resonance ◽  
Relaxation Times ◽  
Target Tissue ◽  
Resonance Imaging ◽  
T2 Relaxation ◽  
Drug Concentrations ◽  
T1 And T2

Abstract Background Anti-tumour necrosis factor antagonists (infliximab) as well as other molecules with different modes of action, including anti-integrin agents (vedolizumab), are currently used in patients with ulcerative colitis (UC Numerous studies have demonstrated a positive correlation between serum biologic drug concentrations and favourable therapeutic outcomes, whereas low or undetectable drug concentrations can lead to treatment failure. However, despite immunological issues, lack of and or loss of response may also be attributed to drug pharmacokinetics, of which penetration to the target tissue (colon wall) may play a crucial role Methods We used MRI to perform biochemical analyses of infliximab, adalimumab and vedolizumab concentrations testing the hypothesis that MRI relaxation time can be used to track antibodies in both mucosal biopsy samples and serum. All MR scans were performed with an Optima MR360 from General Electric Healthcare. To determine spin–lattice (T1) and spin–spin (T2) relaxation times, the Fast Spin Echo (FSE) sequence was used. Results The measured values of T1 relaxation times for infliximab, adalimumab, and vedolizumab were 2227 ± 35 ms, 2000 ± 22 ms and 1288 ± 15 ms, respectively. The obtained T2 relaxation times were 130 ± 11 ms, 90 ± 5, and 75 ± 10 ms, respectively. A decrease of both T1 and T2 values of 15 ± 3% are observed in serum from patients with ulcerative colitis. The values of infliximab and adalimumab were similar; the values of vedolizumab measurements in serum were about 50% lower. We find primary evidence that in T1 and T2 decreased in serum samples with ulcerative colitis and increase with the administration of infliximab, adalimumab and vedolizumab drugs. Samples of healthy tissue have T1 and T2 in the range of 2700 ± 5 ms and 150 ms ± 5 ms, respectively. A 30% decrease in T1 and T2 are observed for samples with ulcerative colitis. In this pilot study, we observed that values of T1 and T2 for tissues and serum that contain infliximab and adalimumab are similar, but vedolizumab shows a difference of about 30% when compared with infliximab and adalimumab. Conclusion MRI is an excellent method for quantitative and qualitative measurements of drug content in tissues and biological fluids. This is an innovative use of magnetic resonance imaging to develop a methodology for imaging of drugs that act as contrast agents via interaction with water in serum and tissue.

Effects of the interaction between ferric iron and L-dopa melanin on T1 and T2 relaxation times determined by magnetic resonance imaging

1992 ◽  
Vol 26 (1) ◽  
pp. 40-45 ◽  
Author(s):  
Jeffrey M. Tosk ◽  
Barbara A. Holshouser ◽  
Roland C. Aloia ◽  
David B. Hinshaw ◽  
Anton N. Hasso ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Ferric Iron ◽  
Relaxation Times ◽  
Resonance Imaging ◽  
T2 Relaxation ◽  
T1 And T2 ◽  
Dopa Melanin

scholarly journals Nuclear Magnetic Resonance Imaging of Grape Buds during the Photoperiodic Induction of Dormancy

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 898D-898 ◽  
Author(s):  
Anne Fennell ◽  
M.J. Line ◽  
M. Faust
Keyword(s):  
Magnetic Resonance Imaging ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Water Status ◽  
Relaxation Times ◽  
The State ◽  
Nuclear Magnetic Resonance Imaging ◽  
Photoperiodic Induction ◽  
Resonance Imaging ◽  
T1 And T2

Changes in water status have been associated with various stages of dormancy and freezing tolerance in woody perennials. Recent studies in apple indicate that changes in the state (bound vs. free) of bud water are strongly correlated with the end of dormancy. In this study nuclear magnetic resonance imaging (NMRI) was used to monitor changes in the state of bud water during the photoperiodic induction of endo-dormancy in Vitis riparia. Bud water status was monitored using proton relaxation times from T1 and T2 images determined at 2, 4, and 6 weeks of long (LD) or short (SD) photoperiod treatments. Bud dormancy was determined by monitoring budbreak in plants defoliated after photoperiod treatments. NMRI allowed nondestructive monitoring of changes in tissue water state. T1 and T2 maps indicated changes in the state of the water in bud and stem tissues during the 6 weeks of treatment. Differences in relaxation times for nondormant and dormancy-induced (reversible) buds were not clear. However, T2 relaxation times were lower in the dormant buds than in the nondormant buds.

scholarly journals MCF-7, ACHN, and A549 Cancer Cells Characterized by Quantitative Magnetic Resonance Imaging In Vitro

2021 ◽  
Vol 12 (4) ◽  
pp. 5174-5186
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Cancer Cells ◽  
Relaxation Times ◽  
Resonance Imaging ◽  
T1 And T2 ◽  
Magnetic Resonance Imaging Mri ◽  
Mcf 7

To work with cancer cell cultures in vitro at 1.5 Tesla Magnetic Resonance Imaging (MRI), it was necessary to develop dedicated receiver coils. This device allowed to adjust the shape of the tested objects and thus improve the quality of imaging. One of the conditions for this new device was to increase the recorded signal level and reduce the distance between the tested object and the receiving elements of the coil. MCF7 (breast adenocarcinoma, Her-2 positive), ACHN (kidney cancer cells), and A549 (lung cancer cells) were characterized by using magnetic resonance imaging (MRI) in vitro. MRI measurements were performed using the clinical scanner with a 1.5 Tesla magnetic field. MCF-7, ACHN, and A549 cancer cells were characterized by T1 and T2 relaxation times. For MCF-7 cells, the relaxation times T1 and T2 were 2360 ± 12 ms and 116 ± 0.9 ms, respectively. For ACHN cells, the relaxation times T1 and T2 were 1354 ± 193 ms and 80 ± 9 ms, respectively. Values of T1 and T2 for A549 cancer cells cultures were 1527 ± 59 ms and 150 ± 8 ms, respectively. Once an accurate pulse protocol has been established and satisfactory reproducibility was obtained, the determination of relaxation times can be used as a tool to monitor cancer cell cultures using MRI in vitro based on the determination of changes in relaxation times.

T2 relaxation time mapping of proximal tibiofibular cartilage by 3-tesla magnetic resonance imaging

2009 ◽  
Vol 50 (9) ◽  
pp. 1049-1056 ◽  
Author(s):  
Kyu-Sung Kwack ◽  
Byoung-Hyun Min ◽  
Jae Hyun Cho ◽  
Jun Man Kim ◽  
Seung-Hyun Yoon ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Relaxation Time ◽  
Magnetic Resonance ◽  
3 Tesla ◽  
T2 Relaxation Time ◽  
Resonance Imaging ◽  
T2 Relaxation
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