scholarly journals Hypoperfusion of the infrapatellar fat pad and its relationship to MRI T2* relaxation time changes in a 5/6 nephrectomy model

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Guo-Shu Huang ◽  
Yi-Jen Peng ◽  
Yu-Juei Hsu ◽  
Herng-Sheng Lee ◽  
Yue-Cune Chang ◽  
...  
Keyword(s):  
Relaxation Time ◽  
T2 Mapping ◽  
Infrapatellar Fat Pad ◽  
Imaging Biomarkers ◽  
Control Group ◽  
T2 Relaxation Time ◽  
Fat Pad ◽  
T2 Relaxation ◽  
Mri Findings ◽  
Dce Mri

AbstractThe purpose of present study was to longitudinally investigate the alterations in infrapatellar fat pad (IPFP) vascularity in 5/6 nephrectomized rats by using dynamic contrast enhanced (DCE) MRI and IPFP degeneration by using MRI T2* relaxation time. Twelve male Sprague–Dawley rats were assigned to a control group and a 5/6 nephrectomy CKD group. The right knees of all rats were longitudinally scanned by 4.7 T MRI, and serial changes in the IPFP were assessed at 0, 8, 16, 30, and 44 weeks by DCE-MRI (parameters A, kel and kep) and MRI T2* mapping. After MRI measurements, knee specimens were obtained and evaluated histologically. The CKD group had IPFPs with lower blood volume A and lower permeability kep values from 16 weeks (p < 0.05), lower venous washout kel value from 30 weeks (p < 0.001), and significantly higher T2* values reflecting adipocyte degeneration beginning at 16 weeks (p < 0.05). The histopathological results confirmed the MRI findings. Hypoperfusion and adipocytes degeneration related to CKD were demonstrated in a rodent 5/6 nephrectomy model. DCE parameters and MRI T2* can serve as imaging biomarkers of fat pad degeneration during CKD progression.

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

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 &lt; 0.01). T2 relaxation time correlated with EAF, and TNF-α and Myod1 expression (r = 0.42, p &lt; 0.05; r = 0.86, p &lt; 0.01; r = 0.84, p &lt; 0.01). The average tensor metrics (MD, λ1, λ2, and λ3) of skeletal muscle at 3 and 5 days of frostbite increased (p &lt; 0.05), and fCSA correlated with λ1, λ2, and λ3, and MD (r = 0.65, p &lt; 0.01; r = 0.48, p &lt; 0.01; r = 0.52, p &lt; 0.01; r = 0.62, p &lt; 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.

scholarly journals Feasibility of T2 Mapping and Magnetic Transfer Ratio for Diagnosis of Intervertebral Disc Degeneration at the Cervicothoracic Junction: A Pilot Study

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Chao Zhang ◽  
Yuan Lin ◽  
Zhihua Han ◽  
Liang Gao ◽  
Ruipeng Guo ◽  
...  
Keyword(s):  
Relaxation Time ◽  
Intervertebral Disc ◽  
Disc Degeneration ◽  
Intervertebral Disc Degeneration ◽  
T2 Mapping ◽  
T2 Relaxation Time ◽  
T2 Relaxation ◽  
Cervicothoracic Junction ◽  
Magnetic Transfer ◽  
Pfirrmann Grade

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.

scholarly journals Analysis of graft maturation after autologous chondrocyte implantation with T2 mapping

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.

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

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.

scholarly journals Baseline Volumetric T2 Relaxation Time Histogram Analysis: Can It Be Used to Predict the Response to Intravenous Methylprednisolone Therapy in Patients With Thyroid-Associated Ophthalmopathy?

2021 ◽  
Vol 12 ◽  
Author(s):  
Ping Liu ◽  
Ban Luo ◽  
Lang Chen ◽  
Qiu-Xia Wang ◽  
Gang Yuan ◽  
...  
Keyword(s):  
Logistic Regression ◽  
Relaxation Time ◽  
Multivariate Logistic Regression Analysis ◽  
Therapy Response ◽  
Imaging Biomarkers ◽  
T2 Relaxation Time ◽  
T2 Relaxation ◽  
Intravenous Methylprednisolone ◽  
Therapy Effect ◽  
Thyroid Associated Ophthalmopathy

ObjectivePrediction of therapy response to intravenous methylprednisolone pulses (ivMP) is crucial for thyroid-associated ophthalmopathy (TAO). Image histograms may offer sensitive imaging biomarkers for therapy effect prediction. This study aimed to investigate whether pretherapeutic, multiparametric T2 relaxation time(T2RT) histogram features of extraocular muscles (EOMs) can be used to predict therapy response.Materials and MethodsForty-five active and moderate-severe TAO patients, who were treated with standard ivMP and underwent orbital MRI before therapy, were retrospectively included in this study. The patients were divided into responsive (n = 24, 48 eyes) and unresponsive group(n = 21, 42 eyes) according to clinical evaluation. Baseline clinical features of patients and histogram-derived T2RT parameters of the EOMs were analyzed and compared. Logistic regression model was conducted to determine independent predictors, and a histogram features nomogram was formulated for personalized prediction.ResultsResponsive group displayed lower values for 5th, 10th percentiles (P &lt; 0.050, respectively), and higher values for 75th, 90th, and 95th percentiles, skewness, entropy, and inhomogeneity (P &lt; 0.050, respectively) than unresponsive group. Multivariate logistic regression analysis showed that 95th percentile of &gt;88.1 [odds ratio (OR) = 12.078; 95% confidence interval (CI) = 3.98–36.655, p &lt; 0.001], skewness of &gt;0.31 (OR = 3.935; 95% CI = 2.28–6.788, p &lt; 0.001) and entropy of &gt;3.41 (OR = 4.375; 95% CI = 2.604–7.351, p &lt; 0.001) were independent predictors for favorable response. The nomogram integration of three independent predictors demonstrated optimal predictive efficiency, with a C-index of 0.792.ConclusionsPre-treatment volumetric T2RT histogram features of EOMs could function to predict the response to ivMP in patients with TAO. The nomogram based on histogram features facilitates the selection of patients who will derive maximal benefit from ivMP.

scholarly journals 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

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.

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

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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