Magnetic Resonance Imaging T2 Mapping Research Articles

The Role of Perfusion Magnetic Resonance Imaging in the Discrimination of Benign vs Malign Character of Musculoskeletal Tumors

Purpose: There may be difficulties in diagnosing musculoskeletal system tumors with Magnetic Resonance Imaging (MRI). Advanced MRI imaging techniques may contribute to noninvasive diagnosis.The aim of our study was to evaluate the performance of perfusion magnetic resonance imaging quantitative data in the differentiation of benign and malignant musculoskeletal tumors. Material and Methods: Thirty-six histologically proven patients were included in the study retrospectively. All patients underwent 1.5-T perfusion MRI (magnetic resonance imaging) with T1 mapping and diffusion MRI. Four quantitative and one semiquantitative parameter were obtained for each tumor using the Toft pharmacokinetic model. ADCmean and ADCmin values were calculated from apparent diffusion coefficient (ADC) maps. Results: Eighteen of 36 patients (50%) had malignant tumors, and 18 had benign tumors. There were 26 soft tissue tumors and 10 bone tissue tumors. Among malignant and benign tumors, the best performance was found in the Ktrans, Kep, Ve values. (p=0.011, p=0.013, p=0,035). Conclusion: Ktrans and Kep values, which are indicators of increased permeability in the tumor, are noninvasive parameters for determining the malignant character of the tumor. The 'Ve' value is an indicator of the extracellular volume of the tumor. Ktrans, Kep and Ve maps can also guide the biopsy.

Evaluation of the impact of ultra-trail running on knee cartilage using magnetic resonance imaging t2 mapping.

Ultra-marathon trails involve a combination of specific physiological and mechanical constraints and raise new questions regarding the osteoarticular impact on the knees and the long-term risk of osteoarthritis. Magnetic resonance imaging (MRI) T2 relaxation time measurement has shown the ability to determine cartilage response to loading. Higher T2 measurements correspond with cartilage damage. The aim of this study was to quantify the changes in MRI T2 relaxation times of knee articular cartilage after an ultra-trail run and determine knee's consequences of regular practice. Twenty participants in a 55-km race involving total elevation changes of 2600m had 1.5-T knee MRI prior to the race (V0), immediately after (V1) and one month after the race (V2) for T2 relaxation times measurement and morphological sequences (T1, T2 & T2 Fast-Spin Echo (FSE)). T2 measurements were significantly increased in V1 from V0 and remained so one month after the race (V2), despite a significant reduction from V1. Morphological sequences revealed that 65% of the participant had cartilage damage and 65% meniscal damage, 100% of which affected the posterior horn of the medial meniscus. Only one subject (5%) presented no anomaly whatsoever. Damage appeared to be stable between the assessments. Ultra-trail running leads to modifications in the knee cartilage ultrastructure, which persists for at least one month after the event. Furthermore, regular ultra-trail runners present a high number of low-grade cartilage and meniscus lesions.

Extracorporeal shockwave therapy for degenerative meniscal tears results in a decreased T2 relaxation time and pain relief: An exploratory randomized clinical trial.

The optimal management of degenerative meniscal tears remains controversial. Extracorporeal shockwave therapy (ESWT) has been shown to promote tissue repair in both preclinical and clinical studies; however, its effect on degenerative meniscal tears remains unknown. This study aimed to examine whether ESWT improves meniscal degeneration. This randomized trial was conducted between 2020 and 2022 and involved patients with degenerative medial meniscal tears. Patients were allocated to receive either focused ESWT (0.25 mJ/mm2, 2000 impulses, 3 sessions with a 1-week interval) or sham treatment. Patients were evaluated using magnetic resonance imaging (MRI) before treatment and at 12 months after treatment. The primary endpoint was improvement in meniscal degeneration, as assessed by the change in T2 relaxation time from baseline on MRI T2 mapping. Knee pain and clinical outcomes were also examined at the same time. Of 29 randomized patients, 27 patients (mean age 63.9 ± 8.7 years; females 37%; ESWT group 14 patients; control group 13 patients) were included in the final analysis. At 12 months postintervention, patients in the ESWT group showed a greater decrease in the T2 relaxation time (ESWT group -2.9 ± 1.7 ms vs. control group 1.0 ± 1.9 ms; p < 0.001) and had less knee pain (p = 0.04). The clinical outcomes at 12 months post-treatment were not statistically significant. No adverse events were reported. ESWT decreased the T2 relaxation time in the meniscus at 12 months post-treatment. ESWT also provided pain relief, but no differences were observed in clinical outcomes. Level II.

The clinical application value of 3.0T magnetic resonance T2 mapping imaging in evaluating the degree of acetabular cartilage degeneration in joint replacement surgery running title: MRI and acetabular cartilage degeneration

BackgroundTo explore and compare the values of 3.0T magnetic resonance imaging (MRI) T2 mapping in evaluating the degree of acetabular cartilage degeneration in hip replacement surgery.MethodsA total of 26 elderly patients with femoral neck fractures who were scanned in 3.0T MRI T2 mapping quantification technique were included. Basing on MRI images, the degree of acetabular cartilage degeneration was classified into Grade 0, 1, 2, 3 and 4, according to the International Cartilage Repair Society (ICRS) scores. In addition, 8 healthy volunteers were included for control group.ResultsBy comparison with health population, T2 relaxation values in the anterior, superior, and posterior regions of acetabular cartilage in patients with femoral neck fracture were obviously increased (P < 0.001). Among the patients with femoral neck fractures, there were 16 hip joint with Grade 1–2 (mild degeneration subgroup) and 10 hip joints with Grade 3–4 (severe degeneration subgroup), accounting for 61.54% and 38.46%, respectively. Additionally, T2 relaxation values in the anterior and superior bands of articular cartilage were positively related to the MRI-based grading (P < 0.05); while there was no significant difference of T2 relaxation values in the posterior areas of articular cartilage between severe degeneration subgroup and mild degeneration subgroup (P > 0.05). Importantly, acetabular cartilage degeneration can be detected through signal changes of T2 mapping pseudo-color images.Conclusion3.0T MRI T2 mapping technology can be used to determine the degree of acetabular cartilage degeneration, which can effectively monitor the disease course.

Magnetic resonance imaging T1 mapping of the liver, pancreas and spleen in children

PurposeTo characterize T1 relaxation times of the pancreas, liver, and spleen in children with and without abdominal pathology.MethodsThis retrospective study included pediatric patients (< 18-years-old). T1 mapping was performed with a Modified Look-Locker Inversion Recovery sequence. Patients were grouped based on review of imaging reports and electronic medical records. The Kruskal–Wallis test with Dunn’s multiple comparison was used to compare groups.Results220 participants were included (mean age: 11.4 ± 4.2 years (1.5 T); 10.9 ± 4.5 years (3 T)). Pancreas T1 (msec) was significantly different between subgroups at 1.5 T (p < 0.0001). Significant pairwise differences included: normal (median: 583; IQR: 561–654) vs. acute pancreatitis (731; 632–945; p = 0.0024), normal vs. chronic pancreatitis (700; 643–863; p = 0.0013), and normal vs. acute + chronic pancreatitis (1020; 897–1099; p < 0.0001). Pancreas T1 was also significantly different between subgroups at 3 T (p < 0.0001). Significant pairwise differences included: normal (779; 753–851) vs. acute pancreatitis (1087; 910–1259; p = 0.0012), and normal vs. acute + chronic pancreatitis (1226; 1025–1367; p < 0.0001).Liver T1 was significantly different between subgroups only at 3 T (p = 0.0011) with pairwise differences between normal (818, 788–819) vs. steatotic (959; 848–997; p = 0.0017) and normal vs. other liver disease (882; 831–904; p = 0.0455). Liver T1 was weakly correlated with liver fat fraction at 1.5 T (r = 0.39; 0.24–0.52; p < 0.0001) and moderately correlated at 3 T (r = 0.64; 0.49–0.76; p < 0.0001).There were no significant differences in splenic T1 relaxation times between subgroups.ConclusionPancreas T1 relaxation times are higher at 1.5 T and 3 T in children with pancreatitis and liver T1 relaxation times are higher in children with steatotic and non-steatotic chronic liver disease at 3 T.

#2974 Serial multiparametric magnetic resonance imaging in a prospective cohort of patients with acute kidney injury

Abstract Background and Aims Recovery from acute kidney injury (AKI) is traditionally measured using serum creatinine but this can often over-estimate the degree of renal recovery. It is known, however, that failure of recovery of serum creatinine 90 days after AKI strongly associates with subsequent long-term reductions in renal function making it an important clinical timepoint. Magnetic resonance imaging (MRI) is an imaging modality with promise to improve the understanding and characterisation of renal pathophysiology. In a single multiparametric MRI (mpMRI) scan, multiple measures can assess renal morphology, tissue microstructure (T1 relaxation time and diffusion-weighted-imaging (DWI)), oxygenation, perfusion and blood flow. We previously published the first study of renal mpMRI at the time of AKI and during follow up, this showed increased total kidney volume (TKV) and T1 as a measure of inflammation/fibrosis at the time of AKI which remained elevated in some participants at 3 and 12 months despite normalisation of serum creatinine. This study aimed to assess the degree of change between 30 and 90 days post AKI, as the first 90 days after AKI appear to be the important in terms of outcomes. Method Prospective observational study of 10 participants with AKI of all stages recruited at the time of AKI and followed up with monthly bloods and urine. MRI scans were collected on a Philips Ingenia 3T at day 30-60 and day 90. The 1-hour protocol included: T2-weighted scans for automated segmentation to compute total kidney volume (TKV), as well as T1 &amp; T2 mapping, DWI, ASL and phase contrast MRI for kidney perfusion and blood flow, and TRUST-MRI and BOLD R2* for kidney oxygenation, and MRE for stiffness. Results 10 participants were scanned at 2 timepoints, (mean day 45 for 1st scan, 95 for 2nd scan). Baseline characteristics are summarised in Table 1 along with key clinical measures in Table 2. 2 participants had CKD at baseline. Despite a range of peak creatinine values and AKI stages the majority of participants serum creatinine normalised to within 20% of baseline by 30 days (v3) (Fig. 1). Fig. 2 shows the TKV for AKI patients across the 2 visits as compared with healthy values. Despite normalisation of biochemistry, 5 participants had enlarged TKV. The predominant AKI aetiology for these patients was sepsis. Across all participants there is little dynamic change between visits. The participant with the small TKV across both visits had pre-existing CKD, as well as the highest peak creatine. The participant did not recover renal function by day 90 (Figs 1(j) and 2). Conclusion Despite recovery of biochemistry, at least half of this AKI cohort had abnormal MR measures at that persisted through one and three months after the AKI episode. There is a trend towards larger TKV in patients with AKI due to sepsis, which needs to be explored in a larger cohort. Analysis of more parameters as well as the addition of liquid biomarkers will enrich these preliminary findings.

Evaluation of articular cartilage degeneration in patients with osteonecrosis of the femoral head using T2 mapping magnetic resonance imaging.

To evaluate and characterise articular cartilage degeneration in patients with osteonecrosis of the femoral head (ONFH) using T2 mapping magnetic resonance imaging. We reviewed 35 patients with ONFH (20 males and 15 females, mean age: 45.7 ± 12.9 years) without obvious cartilage abnormalities on plain magnetic resonance imaging (ONFH group) and 25 healthy volunteers (9 males and 16 females, mean age: 42.9 ± 5.8 years) (control group). All patients underwent T2 mapping magnetic resonance imaging after ONFH onset. The region of interest was defined as the weight-bearing portion of the articular cartilage in the femoral head and acetabulum in the coronal view. The T2 values of the articular cartilage of the acetabulum and femoral head, including necrotic and normal regions, were significantly higher in the ONFH group than those in the control group. These T2 values of the acetabulum and femoral head in Stages 3A and 2 were significantly higher in the ONFH group than those in the control group. The articular cartilage of the acetabulum and femoral head can deteriorate after the onset of ONFH, which may affect the natural history of ONFH and ONFH treatment. Our findings suggest the need for early intervention in joint preservation surgery.

Systematic review of cardiovascular magnetic resonance imaging T1 and T2 mapping in patients with Takotsubo syndrome

BackgroundCurrent imaging advancements quantify the use of cardiovascular magnetic resonance (CMR) derived T1 and T2 tissue characterization as robust indicators for cardiomyopathies, but limited literature exists on its clinical application in Takotsubo syndrome (TTS). This systematic review evaluated the T1 and T2 parametric mapping to delineate the current diagnostic and prognostic CMR imaging outcomes in TTS. MethodsA comprehensive literature search until October 2023 was performed on ScienceDirect, PubMed, Web of Science, and Cochrane Library by two independent reviewers adhering to the PRISMA framework. The Newcastle-Ottawa Scale (NOS) was used to evaluate the methodological quality of studies. ResultsOut of 198 results, 8 studies were included in this qualitative synthesis, accounting for a total population of 399 subjects (TTS = 201, controls = 175, acute myocarditis = 14, and acute regional myocardial oedema without infarction = 9). Approximately 50.4 % were TTS patients aged between 61 and 73 years, whereof, females (n = 181, 90.0 %) and apical variants (n = 180, 89.6 %) were significantly higher, and emotional stressor (n = 42; 20.9 %) was more prevalent than physical (n = 27; 13.4 %). The NOS identified 62.5 % of studies as moderate and 37.5 % as high quality. Parametric tissue mapping revealed significantly prolonged T1 and T2 relaxation times at 1.5T and 3T respectively in TTS (1053–1164 msec, 1292–1438 msec; and 56–67 msec, 60–90 msec) with higher extracellular volume (ECV) fraction (29–36 %), compared to healthy subjects (944–1211 msec, 1189–1251 msec; and 46–54 msec, 32–68 msec; 23–29 %) and myocarditis (1058 msec, 60 msec). Other significant myocardial abnormalities included increased left ventricular (LV) end-systolic and diastolic volume and reduced global longitudinal strain. Overall, myocardial oedema, altered LV mass and strain, and worse LV systolic function, with higher native T1, T2, and ECV values were consistent. ConclusionsFuture research with substantially larger clinical trials is vital to explore the CMR imaging findings in diverse TTS patient cohorts and correlate the T1 and T2 mapping outcomes with demographic/clinical covariates. CMR is a valuable imaging tool for TTS diagnosis and prognostication. T1 and T2 parametric mapping facilitates the quantification of oedema, inflammation, and myocardial injury in Takotsubo.

Magnetic resonance imaging T2 mapping could reflect disease status in patients with dermatomyositis or polymyositis

This study aimed to explore the value of magnetic resonance imaging (MRI) T2 mapping in the assessment of dermatomyositis (DM) and polymyositis (PM). Thirty-three confirmed cases (myosin group) and eight healthy volunteers (healthy control group) at the Department of Rheumatology and Immunology, the First Affiliated Hospital of Kunming Medical University, from October 2016 to December 2017, were collected and analyzed. Multiple parameters of the myosin group were quantified, including creatine kinase (CK), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), complement C3, and complement C4. Disease status was evaluated using a panel of tools: myositis disease activity assessment tool-muscle (MDAAT-muscle), myositis disease activity assessment tool-whole (MDAAT-all), health assessment questionnaire (HAQ), medical outcomes study health survey short form-36 item (SF-36), hand muscle strength test (MMT-8) score, and MRI T2 mapping of muscle (22 muscles in the pelvis and thighs) T2 values. The results showed that in the myositis group, the measurements for CK, ESR, CRP, complement C3, and complement C4 were 457.2 (165.6, 1 229.2) IU/L, 20 (10, 42) mm/1h, 3.25 (2.38, 10.07) mg/L, 0.90 (0.83, 1.06) g/L, and 0.18 (0.14, 0.23) g/L, respectively. The scores for MMT-8, MDAAT-muscle, MDAAT-all, HAQ, and SF-36 were 57.12±16.23, 5.34 (4.00, 6.00), 34.63±12.62, 1.55 (0.66, 2.59), and 44.66±7.98, respectively. T2 values were significantly higher in all 22 muscles of the pelvis and thighs of patients with DM or PM compared with the healthy controls [(54.99±11.60)ms vs. (36.62±1.66)ms, P<0.001], with the most severe lesions in the satrorius, iliopsoas, piriformis, gluteus minimus, and gluteus medius muscles. The total muscle T2 value in the myositis group was positively correlated with CK, MDAAT-muscle, MDAAT-all, and HAQ (r=0.461, 0.506, 0.347, and 0.510, respectively, all P<0.05). There was a negative correlation between complement C4, SF-36, and MMT-8 scores (r=-0.424, -0.549, and -0.686, respectively, all P<0.05). Collectively, the findings from this study suggest that MRI T2 mapping can objectively reflect the disease status of DM and PM.

Functional MRI assessment of microstructural and perfusion changes in the kidneys of rats with intrauterine growth restriction

To explore the value of functional magnetic resonance imaging (MRI) techniques, including intravoxel incoherent motion (IVIM), T1 mapping, and T2 mapping, in assessing the microstructural and perfusion changes in the kidneys of rats with intrauterine growth restriction (IUGR). An IUGR rat model was established through a low-protein diet during pregnancy. Offspring from pregnant rats on a low-protein diet were randomly divided into an IUGR 8-week group and an IUGR 12-week group, while offspring from pregnant rats on a normal diet were divided into a normal 8-week group and a normal 12-week group (n=8 for each group). The apparent diffusion coefficient (ADC), true diffusion coefficient (Dt), pseudo-diffusion coefficient (D*), perfusion fraction (f), T1 value, and T2 value of the renal cortex and medulla were compared, along with serum creatinine and blood urea nitrogen levels among the groups. The Dt value in the renal medulla was higher in the IUGR 12-week group than in the IUGR 8-week group, and the D* value in the renal medulla was lower in the IUGR 12-week group than in both the normal 12-week group and the IUGR 8-week group (P<0.05). The T1 value in the renal medulla was higher than in the cortex in the IUGR 8-week group, and the T1 value in the renal medulla was higher in the IUGR 12-week group than in both the IUGR 8-week group and the normal 12-week group, with the cortical T1 value in the IUGR 12-week group also being higher than that in the normal 12-week group (P<0.05). The T2 values in the renal medulla were higher than those in the cortex across all groups (P<0.05). There were no significant differences in the T2 values of either the cortex or medulla among the groups (P>0.05). There were no significant differences in serum creatinine and blood urea nitrogen levels among the groups (P>0.05). Glomerular hyperplasia and hypertrophy without significant fibrotic changes were observed in the IUGR 8-week group, whereas glomerular atrophy, cystic stenosis, and interstitial inflammatory infiltration and fibrosis were seen in the IUGR 12-week group. IVIM MRI can be used to assess and dynamically observe the microstructural and perfusion damage in the kidneys of IUGR rats. MRI T1 mapping can be used to evaluate kidney damage in IUGR rats, and the combination of MRI T1 mapping and T2 mapping can further differentiate renal fibrosis in IUGR rats.

Iterative Temporal-spatial Transformer-based Cardiac T1 Mapping MRI Reconstruction

The precise reconstruction of accelerated magnetic resonance imaging (MRI) brings about notable advantages, such as enhanced diagnostic precision and decreased examination costs. In contrast, traditional cardiac MRI necessitates repetitive acquisitions across multiple heartbeats, resulting in prolonged acquisition times. Significant strides have been made in accelerating MRI through deep learning-based reconstruction methods. However, these existing methods encounter certain limitations: (1) The intricate nature of heart reconstruction involving multiple complex time-series data poses a challenge in exploring nonlinear dependencies between temporal contexts. (2) Existing research often overlooks weight sharing in iterative frameworks, impeding the effective capturing of non-local information and, consequently, limiting improvements in model performance. In order to improve cardiac MRI reconstruction, we propose a novel temporal-spatial transformer with a strategy in this study. Based on the multi-level encoder and decoder transformer architecture, we conduct multi-level spatiotemporal information feature aggregation over several adjacent views, that create nonlinear dependencies among features and efficiently learn important information among adjacent cardiac temporal frames. Additionally, in order to improve contextual awareness between neighboring views, we add cross-view attention for temporal information fusion. Furthermore, we introduce an iterative strategy for training weights during the reconstruction process, which improves feature fusion in critical locations and reduces the number of computations required to calculate global feature dependencies. Extensive experiments have demonstrated the substantial superiority of this procedure over the most advanced techniques, suggesting that it has broad potential for clinical use.

Use of Atrial Fibrillation Electrograms and T1/T2 Magnetic Resonance Imaging to Define the Progressive Nature of Molecular and Structural Remodeling: A New Paradigm Underlying the Emergence of Persistent Atrial Fibrillation.

The temporal progression states of the molecular and structural substrate in atrial fibrillation (AF) are not well understood. We hypothesized that these can be detected by AF electrograms and magnetic resonance imaging parametric mapping. AF was induced in 43 dogs (25-35 kg, ≥1 year) by rapid atrial pacing (RAP) (3-33 weeks, 600 beats/min), and 4 controls were used. We performed high-resolution epicardial mapping (UnEmap, 6 atrial regions, both atria, 130 electrodes, distance 2.5 mm) and analyzed electrogram cycle length, dominant frequency, organization index, and peak-to-peak bipolar voltage. Implantable telemetry recordings were used to quantify parasympathetic nerve activity over RAP time. Magnetic resonance imaging native T1, postcontrast T1, T2 mapping, and extracellular volume fraction were assessed (1.5T, Siemens) at baseline and AF. In explanted atrial tissue, DNA oxidative damage (8-hydroxy-2'-deoxyguanosine staining) and percentage of fibrofatty tissue were quantified. Cycle length and organization index decreased (R=0.5, P<0.05; and R=0.5, P<0.05; respectively), and dominant frequency increased (R=0.3, P n.s.) until 80 days of RAP but not thereafter. In contrast, voltage continued to decrease throughout the duration of RAP (R=0.6, P<0.05). Parasympathetic nerve activity increased following RAP and plateaued at 80 days. Magnetic resonance imaging native T1 and T2 times increased with RAP days (R=0.5, P<0.05; R=0.6, P<0.05) in the posterior left atrium throughout RAP. Increased RAP days correlated with increasing 8-hydroxy-2'-deoxyguanosine levels and with fibrosis percentage (R=0.5, P<0.05 for both). A combination of AF electrogram characteristics and T1/T2 magnetic resonance imaging can detect early-stage AF remodeling (autonomic remodeling, oxidative stress) and advanced AF remodeling due to oxidative stress and fibrosis.

Evaluation of Open Versus Arthroscopic Anterior Talofibular Ligament Reconstruction for Chronic Lateral Ankle Instability With Talar and Subtalar Cartilage MRI T2 Mapping: A 3-Year Prospective Study.

Previous studies have examined patients with chronic lateral ankle instability (CLAI) undergoing open and arthroscopic anterior talofibular ligament (ATFL) reconstruction, reporting equivalent clinical results between the 2 procedures. However, data on the magnetic resonance imaging (MRI) outcomes on cartilage health after the 2 procedures are limited. To compare the cartilage MRI T2 values of the talar and subtalar joints between patients with CLAI undergoing open and arthroscopic ATFL reconstruction. Cohort study; Level of evidence, 3. A prospective study was conducted on patients who underwent open or arthroscopic ATFL reconstruction between January 2018 and December 2019, with a mean follow-up duration of 3 years. MRI scans and American Orthopaedic Foot & Ankle Society (AOFAS) and Tegner score estimations were completed by patients ≤1 week before surgery, as a baseline measurement, and at a 3-year follow-up. A total of 21 healthy volunteers were included who underwent MRI at baseline. Cartilage health was evaluated using MRI T2 mapping. The talar and subtalar cartilage regions were segmented into 14 subregions. At baseline, patients with CLAI had substantially higher T2 values in the medial anterior, medial center, medial posterior, and lateral center regions on the talus compared with the healthy controls (P = .009, .003, .001, and .025, respectively). Remarkable increases in T2 values in the lateral posterior region on the talus were observed from baseline to follow-up in the open group (P = .007). Furthermore, T2 values were considerably higher in the medial center, medial posterior, lateral posterior, and lateral posterior calcaneal facets of the posterior subtalar joint at follow-up in the arthroscopic group compared with the baseline values (P = .025, .002, .006, and .044, respectively). No obvious differences in ΔT2 values were noted between the 2 groups at follow-up. The AOFAS and Tegner scores remarkably improved from baseline to follow-up for the 2 groups (open: 3.25 ± 0.58 vs 5.13 ± 0.81, P < .001; arthroscopic: 3.11 ± 0.90 vs 5.11 ± 1.08, P < .001), with no considerable difference between them. The elevated T2 values of cartilage could not be fully recovered after open or arthroscopic ATFL reconstruction. Both arthroscopic and open ATFL reconstruction displayed similar effects on cartilage health concerning ΔT2, but the arthroscopic group demonstrated more degenerative cartilage subregions than the open group.

Cortical matrix remodeling as a hallmark of relapsing–remitting neuroinflammation in MR elastography and quantitative MRI

Multiple sclerosis (MS) is a chronic neuroinflammatory disease that involves both white and gray matter. Although gray matter damage is a major contributor to disability in MS patients, conventional clinical magnetic resonance imaging (MRI) fails to accurately detect gray matter pathology and establish a clear correlation with clinical symptoms. Using magnetic resonance elastography (MRE), we previously reported global brain softening in MS and experimental autoimmune encephalomyelitis (EAE). However, it needs to be established if changes of the spatiotemporal patterns of brain tissue mechanics constitute a marker of neuroinflammation. Here, we use advanced multifrequency MRE with tomoelastography postprocessing to investigate longitudinal and regional inflammation-induced tissue changes in EAE and in a small group of MS patients. Surprisingly, we found reversible softening in synchrony with the EAE disease course predominantly in the cortex of the mouse brain. This cortical softening was associated neither with a shift of tissue water compartments as quantified by T2-mapping and diffusion-weighted MRI, nor with leukocyte infiltration as seen by histopathology. Instead, cortical softening correlated with transient structural remodeling of perineuronal nets (PNNs), which involved abnormal chondroitin sulfate expression and microgliosis. These mechanisms also appear to be critical in humans with MS, where tomoelastography for the first time demonstrated marked cortical softening. Taken together, our study shows that neuroinflammation (i) critically affects the integrity of PNNs in cortical brain tissue, in a reversible process that correlates with disease disability in EAE, (ii) reduces the mechanical integrity of brain tissue rather than leading to water accumulation, and (iii) shows similar spatial patterns in humans and mice. These results raise the prospect of leveraging MRE and quantitative MRI for MS staging and monitoring treatment in affected patients.

Abstract 11768: Regression of Inflammation by Cardiac Magnetic Resonance in Chronic Chagasic Patients Treated With Benznidazole

Introduction: Chagas disease (CD) is a neglected disease caused by Trypanosoma cruzi ( T. cruzi ), and benznidazole (BZN) is the most prescribed trypanocidal drug in Brazil in function of its best tolerability profile. While treatment with this drug is effective in acute disease, there is no consensus on its effectiveness in adults with chronic infection. Although it is now accepted that treatment directed against T. cruzi is necessary to avoid the long-term sequelae of the disease, the lack of reliable markers for assessment of treatment efficacy is a major obstacle to evaluating new drugs. Hypothesis: the objective of this study is to determine if BZN treatment reduces cardiac inflammation/fibrosis as assessed by magnetic resonance imaging (MRI), using parametric mapping techniques. Methods: Prospective, multi-center study of chronic CD patients underwent MRI T1 and T2 mapping and extracellular volume measurement (ECV) using the modified Look-Locker inversion recovery (MOLLI) sequence, undergoing treatment with BZN, at a dose of 300 mg/kg daily divided into two doses and taken for 60 days. Absolute change T1 and T2 mapping, ECV, left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV) and left ventricle ejection fraction (LVEF) were analyzed from baseline to 6-month follow-up. Results: 53 patients (females 83%, 53.9 ± 11.9 years old) were studied. LVEDV (149 ± 27ml vs 147 ± 29ml, p = 0.52), LVESV (66 ± 29 vs 64 ± 15, p = 0.65) and LVEF (55 ± 11% vs 57 ± 8%, p = 0,28) did not change between baseline and post treatment. Native T1 time showed reduced values among anterior (1030 ± 41ms vs 1011 ± 52ms, p = 0.011), septal (1052 ± 53ms vs 1006 ± 38ms, p = 0.000) and lateral (1042 ± 55ms vs 1019 ± 44ms, p = 0.003) LV walls. T2 mapping showed reduction in LV septal wall (53 ± 4ms vs 52 ± 3ms, p = 0.005). ECV showed significant reduction from baseline to 6-month follow-up (29.9 ± 3,3% vs 28.2 ± 3.5%, p = 0.0001). Conclusions: For the first time, we observe favorable changes in CMR ECV, T1 and T2 mapping induced by benznidazole therapy in chronic Chagas disease patients. These findings suggest that there may be an opportunity to decrease fibrosis/inflammation in chronic CD patients with the use of this therapeutic approach.

Lateral Meniscal Allograft Transplantation Shows a Long-Term Chondroprotective Effect on Quantitative Magnetic Resonance Imaging T2 Mapping at 7-Year Minimum Follow-Up

PurposeThe purpose of this study was to assess the long-term chondroprotective effect of lateral MAT (meniscal allograft transplantation) using quantitative MRI (magnetic resonance imaging) T2 mapping. MethodsIn patients who underwent isolated lateral MAT, quantitative MRI T2 mapping was conducted preoperatively and postoperatively with at minimum follow-up of 7 years to assess the articular cartilage status. On the sagittal section image bisecting the lateral femoral condyle, the weight-bearing portions of the femoral and tibial articular cartilage were divided into three segments each—six segments in total—based on the meniscal coverage area. The regions of interest analysis were performed on the six segments to measure the mean T2 value. Then, the whole layer was divided into deep and superficial layers for further zonal analysis. The longitudinal change in T2 values was statistically analyzed using paired t-tests. Clinical outcome was evaluated using the Lysholm score. ResultsA total of 31 patients were included in the study, with the MRI follow-up period of a minimum follow-up of 7 years (mean 8.9±1.3 years; range, 7.0–11.2 years). The mean T2 value of the whole layer showed significant improvement in all segments of the femoral cartilage and the posterior segment of tibial cartilage. In the zonal analysis, the mean T2 value of the tibial cartilage showed significant improvement in the superficial layer of the mid to posterior portion, while the deep layer remained stable. In contrast, the mean T2 value of the femoral cartilage showed significant improvement in the superficial and deep layers in all segments. The mean Lysholm score significantly improved from 62.6±12.8 to 90.9±10.5 (P < .001). ConclusionThis study suggests that MAT appears to have a long-term chondroprotective effect on the articular cartilage as judged by quantitative T2 mapping. Level of EvidenceLevel Ⅳ, Case series.

Cardiac MRI T1 and T2 Mapping as a Quantitative Imaging Biomarker in Transthyretin Amyloid Cardiomyopathy

This study aimed to assess the utility of cardiac magnetic resonance imaging (MRI) T1 and T2 mapping as quantitative imaging biomarkers in transthyretin amyloid cardiomyopathy (ATTR-CM). This study retrospectively evaluated 74 patients with confirmed wild-type ATTR-CM who underwent cardiac MRI, 99mTc-labeled pyrophosphate (99mTc-PYP) scintigraphy, and echocardiography. We assessed the quantitative disease parameters, for example, left ventricular ejection fraction (LVEF), and global longitudinal strain (GLS) by echocardiography, native T1, extracellular volume fraction (ECV), and native T2 value by cardiac MRI, heart-to-contralateral ratio (H/CL) by 99mTc-PYP, and high-sensitive cardiac troponin T. Myocardial native T2 of ≥50ms was defined as myocardial edema. Correlations between the disease's quantitative parameters were evaluated, and the ECV was compared to other parameters in ATTR-CM with/without myocardial edema. ECV in all patients with ATTR-CM revealed a strong correlation with native T1 (r=0.62), a moderate correlation with hs-TnT (r=0.59), LVEF (r=-0.48), GLS (r=0.58), and H/CL (r=0.48). Correlations between ECV and other quantitative parameters decreased in ATTR-CM with myocardial edema except for H/CL. Meanwhile, the correlations increased in ATTR-CM without myocardial edema. The presence of myocardial edema affected the interpretation of ECV assessment, although ECV can be a comprehensive imaging biomarker for ATTR-CM. ECV showed a significant correlation with various quantitative disease parameters and can be a reliable disease monitoring marker in patients with ATTR-CM when myocardial edema was excluded.

Evaluation of finger cartilage composition in recreational climbers with 7Tesla T2 mapping magnetic resonance imaging.

Sport climbing may lead to tissue adaptation including finger cartilage before apparent surface damage is detectable. The main aim was to assess finger cartilage composition with T2 mapping in young, active climbers and to compare the results to a non-climbers' collective. A secondary aim was to compare whether differences in cartilage T2 times are observed between older vs. younger volunteers. 7 Tesla MRI of the fingers Dig.2-4 was performed using a multi-echo spin echo sequence. Manual segmentation of 3 ROIs at the metacarpal heads, 1 ROI at the base phalanx and 1 ROI at the proximal interphalangeal joint was performed. Included were 13 volunteers without history of trauma who are regularly performing climbing activities as a recreational sport (>20 h/month). These were age-matched with 10 control subjects not performing climbing activities. Mean age was 32.4 years for the climbing group and 25.8 years for the controls. Mean T2 values for the 5 different ROIs were 42.2 ± 7.8 msec for climbers and 41.4 ± 6.8 msec for non-climbers. No significant differences were observed for T2 values between both groups. However, higher age had a significant impact on T2 values for all assessed ROIs (higher age 44.2 ± 9.5, younger age 32.9 ± 5.7, p = 0.001). This study evaluated the cartilage composition of young, engaged climbers with a T2 mapping MRI technique with the purpose to depict early onset joint changes. No negative impact on cartilage composition due to the sport activity was found, whereas age-related effects on the cartilage seemed to be more prominent.

Radiomic Analysis of Quantitative T2 Mapping and Conventional MRI in Predicting Histologic Grade of Bladder Cancer.

We explored the added value of a radiomic strategy based on quantitative transverse relaxation (T2) mapping and conventional magnetic resonance imaging (MRI) to evaluate the histologic grade of bladder cancer (BCa) preoperatively. Patients who were suspected of BCa underwent pelvic MRI (including T2 mapping and diffusion-weighted imaging (DWI) before any treatment. All patients with histological-proved urothelial BCa were included. We constructed different prediction models using the mean signal values and radiomic features from both T2 mapping and apparent diffusion coefficient (ADC) maps. The diagnostic performance of each model or parameter was assessed using receiver operating characteristic curves. In total, 92 patients were finally included (training cohort, n = 64; testing cohort, n = 28); among these, 71 had high-grade BCa. In the testing cohort, the T2-mapping radiomic model achieved the highest prediction performance (area under the curve (AUC), 0.87; 95% confidence interval (CI), 0.73-1.0) compared with the ADC radiomic model (AUC, 0.77; 95%CI, 0.56-0.97), and the joint radiomic model of 0.78 (95%CI, 0.61-0.96). Our results demonstrated that radiomic mapping could provide more information than direct evaluation of T2 and ADC values in differentiating histological grades of BCa. Additionally, among the radiomic models, the T2-mapping radiomic model outperformed the ADC and joint radiomic models.

Added Value of MRI Knee Cartigram in Assessment of Anterior Knee Pain in Comparison to Conventional Standard MRI

Background Osteoarthritis (OA) is a multi-tissue, multi-factorial disease and worldwide a major cause of disability resulting from reduced joint mobility and function. Progressive loss of hyaline cartilage is one of the hallmark features of osteoarthritis, initiated by a loss of proteoglycans and an increase in water content, followed by a loss of type II collagen and a change in collagen fiber orientation. Objective To evaluate the role of T2 mapping in detection of degenerative changes in articular cartilage of knee joint as compared to standard clinical magnetic resonance imaging (MRI) at 1.5T. Patients and Methods From April 2020 to November 2020, this prospective Study was done to use T2 mapping to visualize the articular cartilage of the knee on 1.5 T MR Scanner using special software to evaluate the efficiency Of T2 mapping to detect cartilage lesions. The material of this study included 380 patients. The study includes all of them come complaining of knee pain and 2 of them had previous minor knee trauma, each patient had a single MRI exanimation including conventional MRI routine protocol and added a single complementary T2 mapping. Results there were significant differences between T2 mapping and conventional MRI sequence in the ability to detect cartilage degeneration as T2 mapping was capable of detecting all lesions that were visible on the clinical MRI. Moreover, T2 mapping showed more cartilage lesions than clinical MRI T2 mapping showed more cartilage lesions than clinical MRI, and in T2 maps the lesions appeared generally wider. This proposes that T2 mapping is feasible in the clinical setting and may reveal cartilage lesions not seen on the standard knee MRI. Conclusion Our results suggest that T2 mapping is an interesting MRI sequence for the exploration of patients articular cartilage in and should be included in the routine protocol if cartilage pathology is suspecting as it may improve the diagnostic accuracy of MRI for focal chondral lesions, and should help decide whether and MR-arthrography or CT-arthrography is necessary.