Lumbar vertebral T2-relaxation time investigated with T2-mapping at multiple time points in a day demonstrate large individual variations

Background. Intervertebral disc degeneration (IDD) at the cervicothoracic junction of spine is clinically relevant, however, little attention had been paid. T2 mapping and magnetic transfer ratio (MTR) are useful magnetic resonance imaging (MRI) techniques to quantitatively evaluate IDD, revealing the biochemical changes within the intervertebral disc. To compare T2 mapping with MTR imaging regarding their accuracy to quantitatively diagnose intervertebral disc degeneration at the cervicothoracic junction, influences of anatomical level, gender, age, and Pfirrmann grade of T2 relaxation time values and MTR values were evaluated. Methods. Sixty-seven patients with neck and upper back pain were included and examined with both T2 mapping and MTR imaging. The Pfirrmann grade, T2 relaxation time values, and MTR value of each disc between C7 and T3 were measured. Differences were investigated among different segmental levels, genders, age ranges, and Pfirrmann grades. The diagnostic accuracy of both MRI techniques was compared using the receiver operating characteristic (ROC) curves. Results. No significant difference was detected comparing T2 relaxation time values or MTR values among different anatomical levels, genders, and segmental levels. And we generally found that T2 relaxation time values decreased, while MTR value increased with increasing age. Importantly, we demonstrated the significant correlation between either T2 relaxation time values or MTR value and Pfirrmann grade. Conclusion. We proved the better accuracy of T2 mapping over MTR imaging to quantitatively evaluate the intervertebral disc degeneration of the cervicothoracic junction.

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Analysis of graft maturation after autologous chondrocyte implantation with T2 mapping

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967117s00153 ◽

2017 ◽

Vol 5 (4_suppl4) ◽

pp. 2325967117S0015

Author(s):

Thomas R. Niethammer ◽

Ansgar Loitzsch ◽

Matthias F. Pietschmann ◽

Peter E. Müller ◽

Annie Horng

Keyword(s):

Relaxation Time ◽

Autologous Chondrocyte Implantation ◽

T2 Mapping ◽

Cartilage Defects ◽

T2 Relaxation Time ◽

T2 Relaxation ◽

Postoperative Course ◽

Defect Localization ◽

Chondrocyte Implantation ◽

Autologous Chondrocyte

Aims and Objectives: It has been shown in numerous clinical studies that matrix-based autologous chondrocyte implantation (mb-ACI) leads to good clinical results in the medium-term course. But chondrogenic development of ACI grafts and the time of graft maturation are still unclear. The aim of this study was to investigate the graft maturation after mb-ACI with T2 mapping in the postoperative course of four years. Materials and Methods: In a total of 90 patients could be included after matrix-based autologous chondrocyte transplantation of the knee. All cartilage defects were treated with NOVOCART® 3D. The evaluation of the ACI grafts was conducted after 3, 6, 12, 24, 36 and 48 months by MRI. The T2 relaxation time values of the ACI graft and healthy native cartilage areas were determined to assess graft maturation using T2 mapping. MOCART score were used for morphological evaluation of ACI grafts. Results: The T2 relaxation time of ACI grafts showed a significant improvement during the postoperative course at all time points. The T2 relaxation improved from 48.0 ms after 3 months to 34.6 ms after four years. We found a significant influence of the patient’s age and the defect localization on the T2 relaxation time measuring. It could be detected an increasing integration of the ACI grafts into the healthy surrounding cartilage. No significant differences between the T2 relaxation time of ACI grafts and the surrounding healthy cartilage were found after 12 months postoperatively. Conclusion: Graft maturation after ACI in the knee joint needs at least 1 year, with ongoing adjustment of the T2 relaxation time values compared with native surrounding cartilage. Regarding the age and defect localization, significantly worse T2 relaxation times of the ACI grafts could be found with higher age and in cases with treated patellar defects.

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A Longitudinal Study of T2 Mapping Combined With Diffusion Tensor Imaging to Quantitatively Evaluate Tissue Repair of Rat Skeletal Muscle After Frostbite

Frontiers in Physiology ◽

10.3389/fphys.2020.597638 ◽

2021 ◽

Vol 11 ◽

Author(s):

Yue Gao ◽

Zhao Lu ◽

Xiaohong Lyu ◽

Qiang Liu ◽

Shinong Pan

Keyword(s):

Skeletal Muscle ◽

Relaxation Time ◽

Diffusion Tensor Imaging ◽

Muscle Injury ◽

Diffusion Tensor ◽

T2 Mapping ◽

Imaging Biomarkers ◽

T2 Relaxation Time ◽

T2 Relaxation ◽

Skeletal Muscle Injury

Purpose: T2 mapping and diffusion tensor imaging (DTI) enable the detection of changes in the skeletal muscle microenvironment. We assessed T2 relaxation times, DTI metrics, performed histological characterization of frostbite-induced skeletal muscle injury and repair, and provided diagnostic imaging biomarkers.Design and Methods: Thirty-six Sprague Dawley rats (200 ± 10 g) were obtained. Thirty rats were used for establishing a skeletal muscle frostbite model, and six were untreated controls. Functional MR sequences were performed on rats on days 0, 3, 5, 10, and 14 (n = 6 per time point). Rats were then sacrificed to obtain the quadriceps muscles. Tensor eigenvalues (λ1, λ2, and λ3), mean diffusivity (MD), fractional anisotropy (FA), and T2 values were compared between the frostbite model and control rats. ImageJ was used to measure the extracellular area fraction (EAF), muscle fiber cross-sectional area (fCSA), and skeletal muscle tumor necrosis factor α (TNF-α), and Myod1 expression. The correlation between the histological and imaging parameters of the frostbitten skeletal muscle was evaluated. Kolmogorov–Smirnoff test, Leven’s test, one-way ANOVA, and Spearman coefficient were used for analysis.Results: T2 relaxation time of frostbitten skeletal muscle was higher at all time points (p < 0.01). T2 relaxation time correlated with EAF, and TNF-α and Myod1 expression (r = 0.42, p < 0.05; r = 0.86, p < 0.01; r = 0.84, p < 0.01). The average tensor metrics (MD, λ1, λ2, and λ3) of skeletal muscle at 3 and 5 days of frostbite increased (p < 0.05), and fCSA correlated with λ1, λ2, and λ3, and MD (r = 0.65, p < 0.01; r = 0.48, p < 0.01; r = 0.52, p < 0.01; r = 0.62, p < 0.01).Conclusion: T2 mapping and DTI imaging detect frostbite-induced skeletal muscle injury early. This combined approach can quantitatively assess skeletal muscle repair and regeneration within 2 weeks of frostbite. Imaging biomarkers for the diagnosis of frostbite were suggested.

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P3099Lymphatic insufficiency increases cardiac edema after myocardial infarction as assessed by novel magnetic resonance TRAFFn and T2 relaxation times

European Heart Journal ◽

10.1093/eurheartj/ehz745.0175 ◽

2019 ◽

Vol 40 (Supplement_1) ◽

Author(s):

E Yla-Herttuala ◽

T Vuorio ◽

S Laidinen ◽

S Yla-Herttuala ◽

T Liimatainen

Keyword(s):

Myocardial Infarction ◽

Relaxation Time ◽

Lymphatic Vessel ◽

Lymphatic System ◽

Relaxation Times ◽

T2 Relaxation Time ◽

T2 Relaxation ◽

Time Points ◽

Cardiac Edema ◽

Sirius Red

Abstract Introduction The role of cardiac lymphatic system in myocardial infarction (MI) is still unclear. A new method to detect and characterize MI without contrast agent is a relaxation along a fictitious field in nth rotating frame (RAFFn). The RAFFn takes advantage of the fictitious magnetic field, which is produced by a fast sweep of an effective radio frequency field, to increase a spin locking field strength without increasing the specific absorption rate. MI is detected as increased RAFFn relaxation times and cardiac edema by an increased T2 relaxation time. We have shown earlier that MI size can be accurately measured by the RAFFn relaxation times. Purpose To study the effects of the lack of cardiac lymphatic system on MI and cardiac edema in a mouse model. Methods Transgenic (TG) mice expressing soluble decoy VEGF receptor 3 (sVEGFR3) thus blocking lymphatic vessel formation in the heart and wild type (WT) control mice were used. MI was induced in 13–17 week old TG (n=11) and WT (n=14) mice by ligating the left anterior descending coronary artery. The RAFFn (TRAFF2 and TRAFF4), a continuous wave T1ρ and a T2 relaxation times were acquired at time points 0, 3, 7 and 21 days after the MI at 9.4 T. Histological sections were stained with hematoxylin eosin and Sirius red to assess cellularity and MI area. An Area of difference (AOD) was determined by subtracting MI areas based on TRAFF2, TRAFF4 and T1ρ maps from MI area based on T2 maps. Results MI size based on the TRAFF4 and T2 relaxation time maps were larger at early time points 3 and 7 days post MI in the WT group compared to the TG group (Figure 1A-B, p<0.05). However, the MI size was significantly larger in the T2 relaxation time map in the TG group compared to the WT group at the last time point and interaction between the groups were significant as a function of time (Figure 1A-B, p<0.05). The AOD values, which reflect cardiac edema, increased in the TG group as a function of time (Figure 1C, p<0.001). TRAFF2, TRAFF4 (Figure 1D), T1ρ and T2 relaxation times increased significantly (≈50%, p<0.001) after the MI compared to remote areas in both groups. In the WT group, the lymphatic vessel network is fully functional and removes edema efficiently between days 3 and 21 after the MI, while in the TG group the MI area in T2 map is relative stable indicating insufficient edema removal, caused by the lymphatic deficiency and insufficient lymphangiogenesis in the TG group. The MIs were also verified based on Sirius red stained histology (Figure 1E). Figure 1 Conclusion Lymphatic deficiency increases cardiac edema (AOD values) 7–21 days after MI as compared to the WT group. Results support the importance of cardiac lymphatic vessels for healing after MI. Effects of the lymphatics on MI can be detected based on the MI size difference based on the TRAFFn and the T2 relaxation times. Acknowledgement/Funding Doctoral Programme of Molecular Medicine

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Magnetic resonance imaging quantitative T2* mapping to predict the red blood cell content of in vivo thrombi retrieved from patients with large vessel occlusions in acute ischemic stroke

Interventional Neuroradiology ◽

10.1177/15910199211042473 ◽

2021 ◽

pp. 159101992110424

Author(s):

Alize Gilbert ◽

Lili Detraz ◽

Pierre-Louis Alexandre ◽

Jean-Michel Serfaty ◽

Hubert Desal ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Relaxation Time ◽

Magnetic Resonance ◽

Blood Cell ◽

Red Blood Cell ◽

T2 Mapping ◽

T2 Relaxation Time ◽

Resonance Imaging ◽

T2 Relaxation ◽

Cell Content

Background and purpose Magnetic resonance imaging quantitative T2* mapping has shown reliable identification of thrombus red blood cell content in vitro. The thrombus composition has been in vivo, associated with outcomes after endovascular therapy for acute ischemic stroke. We aim to analyze the red blood cell content of thrombi retrieved from patients with large vessel occlusions in relation to the thrombus-T2* relaxation time in magnetic resonance imaging. Material and methods Consecutive acute ischemic stroke patients treated by endovascular therapy were scanned with an magnetic resonance imaging quantitative T2* mapping sequence. Quantitative histologic evaluations of red blood cell content were performed. A linear regression assessed the association between vascular risk factors, comorbidities, antithrombotic drugs intake, baseline National Institutes of Health Stroke Scale (NIHSS), intravenous thrombolysis before endovascular therapy, time between onset and groin puncture, patient's outcome at 3 months, magnetic resonance imaging quantitative T2* mapping results, and the red blood cell content of thrombi. The correlation between the mean thrombus-T2* relaxation time and red blood cell content was assessed by calculating the Pearson correlation coefficient. Results Among 31 thrombi, 16 were “Fibrin rich” and 15 “red blood cell dominant.” The median red blood cell content was 39 (range, 0–90; interquartile range, 37). The median (interquartile range) thrombus-T2* relaxation time was shorter in “red blood cell dominant” thrombi (21, interquartile range 6) than in “Fibrin rich” thrombi (24, interquartile range 7), without significant difference ( p = 0.15), as shown in the Box plot. An inverse correlation between thrombus-T2* relaxation time and red blood cell content was found, with a correlation coefficient of −0.41 (95% CI, −0.67 to −0.08, p = 0.02). Conclusion Our study shows that a shorter thrombus-T2* relaxation time is related to a higher red blood cell content within in vivo thrombi.

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Multivariable non-invasive association of isocitrate dehydrogenase mutational status in World Health Organization grade II and III gliomas with advanced magnetic resonance imaging T2 mapping techniques

The Neuroradiology Journal ◽

10.1177/1971400919890099 ◽

2020 ◽

Vol 33 (2) ◽

pp. 160-168

Author(s):

Maike Kern ◽

Timo A Auer ◽

Uli Fehrenbach ◽

Yasemin Tanyildizi ◽

Thomas Picht ◽

...

Keyword(s):

Relaxation Time ◽

T2 Mapping ◽

Relaxation Times ◽

World Health ◽

T2 Relaxation Time ◽

Resonance Imaging ◽

T2 Relaxation ◽

Mutational Status ◽

Grade Ii ◽

Health Organization

Aim To investigate multivariable analyses for noninvasive association of the isocitrate dehydrogenase (IDH) mutational status in grade II and III gliomas including evaluation of T2 mapping-sequences. Methods Magnetic resonance imaging (MRI) examinations with histopathologically proven World Health Organization grade II and III gliomas were retrospectively enrolled. Multivariate receiver operating characteristics (ROC) analyses to associate IDH mutational status were performed containing quantitative T2 mapping analyses and qualitative characteristics (sex, age, localization, heterogeneity, oedema, necrosis and diameter). Relaxation times were calculated pixelwise by means of standardized ROI analyses. Interobserver variability also was tested. Results Out of 32 patients (mean age: 50.7 years; range: 32–83), nine had grade II gliomas and 24 grade III, while 59.5% showed a positive IDH mutated state (IDHm) and 40.5% were wildtype (IDHw). Multivariable ROC analyses were calculated for relaxation time and range, localization and age with a cumulative 0.955 area under the curve (AUC) ( p < 0.001), while central T2-relaxation time had by far the highest single variable sensitivity (AUC: 0.873; range: 0.762; age: 0.809; localization: 0.713). Age (cut off: 49 years; p = 0.031) and localization ( p = 0.014) were the only qualitative parameters found to be significant as IDHw gliomas were older and IDHm gliomas were preferentially located fronto-temporal. Conclusions This is the first study evaluating quantitative T2 mapping sequences for association of the IDH mutational status in grade II and III gliomas demonstrating an association between relaxation time and mutational status. Analyses of T2 mapping relaxation times may even be suitable for predicting the correct IDH mutational state. Prognostic accuracy increases significantly in predicting the correct mutational state when combing T2 relaxation time characteristics and the qualitative MRI features age and localization.

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T2 mapping of the extraocular muscles in healthy volunteers: preliminary research on scan–rescan and observer–observer reproducibility

Acta Radiologica ◽

10.1177/0284185119879681 ◽

2019 ◽

Vol 61 (6) ◽

pp. 804-812

Author(s):

Wen Qian ◽

Wei Chen ◽

Xiao-Quan Xu ◽

Fei-Yun Wu

Keyword(s):

Relaxation Time ◽

Healthy Volunteers ◽

Coefficient Of Variation ◽

T2 Mapping ◽

Extraocular Muscles ◽

T2 Relaxation Time ◽

T2 Relaxation ◽

Short Term ◽

3.0 T

Background T2-mapping technique and derived T2 relaxation time allows quantitative assessment of extraocular muscles; however, the reproducibility of T2 mapping-derived parameters was seldom studied till now. Purpose To evaluate the scan–rescan and observer–observer reproducibility of T2 relaxation time measurements of extraocular muscles in young healthy volunteers. Material and Methods Fourteen volunteers underwent T2-mapping examinations of the extraocular muscles three times within one month on a 3.0-T MR system. Scan–rescan and observer–observer reproducibility of T2 relaxation time measurements of the extraocular muscles were assessed using intraclass correlation coefficient and coefficient of variation. Results Both scan–rescan (short-term and long-term) and observer–observer could achieve good to excellent reproducibility, while better short-term than long-term scan–rescan reproducibility was obtained. The coefficient of variation of the T2 relaxation time of each extraocular muscles during both scan–rescan and observer–observer reproducibility assessment were <6%. Conclusion T2 relaxation time measurement of the extraocular muscles is proven to be highly reproducible at 3.0 T. T2 mapping may be a potential imaging technique in the diagnosis and follow-up of orbital diseases involved extraocular muscles in further studies.

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T2 mapping in orbital masses: preliminary study on differential diagnostic ability of T2 relaxation time

Acta Radiologica ◽

10.1177/0284185119874476 ◽

2019 ◽

Vol 61 (5) ◽

pp. 668-674

Author(s):

Yan Zhou ◽

Xiao-Quan Xu ◽

Hao Hu ◽

Guo-Yi Su ◽

Hu Liu ◽

...

Keyword(s):

Relaxation Time ◽

Predictive Value ◽

T2 Mapping ◽

Characteristic Curve ◽

Preoperative Assessment ◽

Diagnostic Value ◽

Quantitative Information ◽

T2 Relaxation Time ◽

T2 Relaxation ◽

Orbital Masses

Background T2 mapping has been proven to be useful in tumor characterization. As to orbital masses, its diagnostic value needs to be investigated. Purpose To evaluate the usefulness of T2 mapping in orbital masses and the ability of T2 relaxation time in differentiating malignant from benign orbital masses. Material and Methods Forty-seven patients with solid orbital masses (33 benign and 14 malignant) who underwent T2 mapping examination for preoperative assessment were enrolled in the current study. T2 mapping was acquired using 16 TE values (range 12–192 ms; delta TE 12 ms). Mean T2 relaxation time was calculated based on the whole mass region of interest and compared between the malignant and benign groups using the unpaired t-test. Receiver operating characteristic curve analysis was adopted to calculate its diagnostic value. Results Malignant orbital masses showed significantly lower T2 relaxation time than benign masses (76.4 ± 13.0 ms vs. 119.1 ± 20.4 ms; P < 0.001). If setting a T2 relaxation time of 89.5 ms as the threshold value, optimal differentiating performance could be achieved (area under the curve 0.936; sensitivity 100.0%; specificity 87.9%; accuracy 91.5%; positive predictive value 77.8%; negative predictive value 100%). Conclusion T2 mapping and its derived T2 relaxation time could provide quantitative information and serve as a supplementary imaging marker for differentiating malignant from benign orbital masses.

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