T1 and T2 relaxation times on gadolinium-diethylenetriaminepentaacetic acid enhanced magnetic resonance images of brain tumors.

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.

Download Full-text

Reliability of Synthetic Brain MRI for Assessment of Ischemic Stroke with Phantom Validation of a Relaxation Time Determination Method

Journal of Clinical Medicine ◽

10.3390/jcm9061857 ◽

2020 ◽

Vol 9 (6) ◽

pp. 1857

Author(s):

Chia-Wei Li ◽

Ai-Ling Hsu ◽

Chi-Wen C. Huang ◽

Shih-Hung Yang ◽

Chien-Yuan Lin ◽

...

Keyword(s):

Ischemic Stroke ◽

Relaxation Time ◽

Brain Mri ◽

Relaxation Times ◽

Onset Time ◽

Magnetic Resonance Images ◽

Diagnostic Tools ◽

Cupric Sulfate ◽

T2 Relaxation ◽

T1 And T2

The reliability of relaxation time measures in synthetic magnetic resonance images (MRIs) of homemade phantoms were validated, and the diagnostic suitability of synthetic imaging was compared to that of conventional MRIs for detecting ischemic lesions. Phantoms filled with aqueous cupric-sulfate (CuSO4) were designed to mimic spin-lattice (T1) and spin-spin (T2) relaxation properties and were used to compare their accuracies and stabilities between synthetic and conventional scans of various brain tissues. To validate the accuracy of synthetic imaging in ischemic stroke diagnoses, the synthetic and clinical scans of 18 patients with ischemic stroke were compared, and the quantitative contrast-to-noise ratios (CNRs) were measured, using the Friedman test to determine significance in differences. Results using the phantoms showed no significant differences in the interday and intersession synthetic quantitative T1 and T2 values. However, between synthetic and referenced T1 and T2 values, differences were larger for longer relaxation times, showing that image intensities in synthetic scans are relatively inaccurate in the cerebrospinal fluid (CSF). Similarly, CNRs in CSF regions of stroke patients were significantly different on synthetic T2-weighted and T2-fluid-attenuated inversion recovery images. In contrast, differences in stroke lesions were insignificant between the two. Therefore, interday and intersession synthetic T1 and T2 values are highly reliable, and discrepancies in synthetic T1 and T2 relaxation times and image contrasts in CSF regions do not affect stroke lesion diagnoses. Additionally, quantitative relaxation times from synthetic images allow better estimations of ischemic stroke onset time, consequently increasing confidence in synthetic MRIs as diagnostic tools for ischemic stroke.

Download Full-text

Magnetic resonance fingerprinting using echo-planar imaging: Joint quantification of T1 and T2∗ relaxation times

Magnetic Resonance in Medicine ◽

10.1002/mrm.26561 ◽

2016 ◽

Vol 78 (5) ◽

pp. 1724-1733 ◽

Cited By ~ 26

Author(s):

Benedikt Rieger ◽

Fabian Zimmer ◽

Jascha Zapp ◽

Sebastian Weingärtner ◽

Lothar R. Schad

Keyword(s):

Magnetic Resonance ◽

Relaxation Times ◽

Echo Planar Imaging ◽

Planar Imaging ◽

T2 Relaxation ◽

T1 And T2 ◽

Echo Planar

Download Full-text

P417Assessment of magnetic resonance imaging scanner-dependence and software-dependence of T1 and T2 relaxation times measurements at 1.5 T

European Heart Journal - Cardiovascular Imaging ◽

10.1093/ehjci/jez118.005 ◽

2019 ◽

Vol 20 (Supplement_2) ◽

Author(s):

D Cicolari ◽

D Lizio ◽

P Pedrotti ◽

R Sironi ◽

M T Moioli ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Magnetic Resonance ◽

Relaxation Times ◽

Resonance Imaging ◽

T2 Relaxation ◽

Magnetic Resonance Imaging Scanner ◽

T1 And T2

Download Full-text

Characterization of Experimental Ischemic Brain Edema Utilizing Proton Nuclear Magnetic Resonance Imaging

Journal of Cerebral Blood Flow & Metabolism ◽

10.1038/jcbfm.1986.34 ◽

1986 ◽

Vol 6 (2) ◽

pp. 212-221 ◽

Cited By ~ 84

Author(s):

Hiroyuki Kato ◽

Kyuya Kogure ◽

Hitoshi Ohtomo ◽

Masahiro Izumiyama ◽

Muneshige Tobita ◽

...

Keyword(s):

Nuclear Magnetic Resonance ◽

Magnetic Resonance ◽

Water Content ◽

Relaxation Times ◽

Nmr Imaging ◽

Tissue Water Content ◽

T2 Relaxation ◽

Tissue Water ◽

T1 And T2 ◽

Nuclear Magnetic

Correlations between T1 and T2 relaxation times and water and electrolyte content in the normal and ischemic rat and gerbil brains were studied by means of both nuclear magnetic resonance (NMR) spectroscopic and imaging methods. In the spectroscopic experiment on excised rat brains, T1 was linearly dependent on tissue water content and T2 was prolonged in edematous tissue to a greater extent than expected by an increase in water content, showing that T2 possesses a greater sensitivity for edema identification and localization. Changes in Na+ and K+ content of the tissue mattered little in the prolongation of relaxation times. Serial NMR imaging of gerbil brains insulted with permanent hemispheric ischemia offered early lesion detection in T1- and especially T2-weighted images (detection as soon as 30 min after insult). The progressive nature of lesions was also imaged. Calculated T1 and T2 relaxation times in regions of interest correlated excellently with tissue water content ( r = 0.892 and 0.744 for T1 and T2, respectively). As a result, detection of cerebral ischemia utilizing NMR imaging was strongly dependent on a change in tissue water content. The different nature of T1 and T2 relaxation times was also observed.

Download Full-text

PRIMARY MALIGNANT MELANOMA OF THE CEREBELLOPONTINE ANGLE

Neurosurgery ◽

10.1227/01.neu.0000245613.86484.36 ◽

2006 ◽

Vol 59 (6) ◽

pp. E1336-E1336 ◽

Cited By ~ 4

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.

Download Full-text

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

Schizophrenia Research ◽

10.1016/0920-9964(91)90080-b ◽

1991 ◽

Vol 5 (3) ◽

pp. 223-232 ◽

Cited By ~ 22

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

Download Full-text

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

Journal of Crohn s and Colitis ◽

10.1093/ecco-jcc/jjz203.139 ◽

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.

Download Full-text

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

Magnetic Resonance in Medicine ◽

10.1002/mrm.1910260105 ◽

1992 ◽

Vol 26 (1) ◽

pp. 40-45 ◽

Cited By ~ 32

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

Download Full-text

Magnetic Resonance Relaxometry for Tumor Cell Density Imaging for Glioma: An Exploratory Study via 11C-methionine PET and Its Validation via Stereotactic Tissue Sampling

Cancers ◽

10.3390/cancers13164067 ◽

2021 ◽

Vol 13 (16) ◽

pp. 4067

Author(s):

Manabu Kinoshita ◽

Masato Uchikoshi ◽

Souichiro Tateishi ◽

Shohei Miyazaki ◽

Mio Sakai ◽

...

Keyword(s):

Relaxation Time ◽

Magnetic Resonance ◽

Tumor Cell ◽

Relaxation Times ◽

Tissue Sampling ◽

T2 Relaxation ◽

T1 Relaxation Time ◽

T1 Relaxation ◽

Tumor Load ◽

T1 And T2

One of the most crucial yet challenging issues for glioma patient care is visualizing non-contrast-enhancing tumor regions. In this study, to test the hypothesis that quantitative magnetic resonance relaxometry reflects glioma tumor load within tissue and that it can be an imaging surrogate for visualizing non-contrast-enhancing tumors, we investigated the correlation between T1- and T2-weighted relaxation times, apparent diffusion coefficient (ADC) on magnetic resonance imaging, and 11C-methionine (MET) on positron emission tomography (PET). Moreover, we compared the T1- and T2-relaxation times and ADC with tumor cell density (TCD) findings obtained via stereotactic image-guided tissue sampling. Regions that presented a T1-relaxation time of >1850 ms but <3200 ms or a T2-relaxation time of >115 ms but <225 ms under 3 T indicated a high MET uptake. In addition, the stereotactic tissue sampling findings confirmed that the T1-relaxation time of 1850–3200 ms significantly indicated a higher TCD (p = 0.04). However, ADC was unable to show a significant correlation with MET uptake or with TCD. Finally, synthetically synthesized tumor load images from the T1- and T2-relaxation maps were able to visualize MET uptake presented on PET.

Download Full-text