MRI T2 Mapping Research Articles

Feature Tracking of Global Longitudinal Strain by Using Cardiovascular MRI Improves Risk Stratification in Heart Failure with Preserved Ejection Fraction

Background In heart failure with preserved ejection fraction (HFpEF), echocardiographic studies suggest that global longitudinal strain (GLS) has an impact on survival. Feature-tracking cardiovascular MRI also allows for strain analysis; however, to the knowledge of the authors, little is known about its prognostic value and whether it reflects severity of diffuse fibrosis, as assessed by cardiovascular MRI T1 mapping. Purpose To investigate the association between myocardial strain at cardiovascular MRI with extracellular volume by T1 mapping and outcome in participants with HFpEF. Materials and Methods In this secondary analysis of a prospective study (NCT03405987), consecutive participants with HFpEF underwent cardiovascular MRI between July 2012 and March 2018, including T1 mapping and three-dimensional strain analysis. Extracellular volume and strain results were assessed to determine if there was a correlation between these two factors. Cox regression was performed to determine the prognostic relevance of MRI-derived myocardial strain for a combined end point (events) of heart failure hospitalizations and cardiovascular death. Results In total, 206 consecutive participants with HFpEF (mean age, 71 years ± 8 [standard deviation]; 69% women) were included. Median myocardial global longitudinal strain (GLS) at MRI was -8.5% and showed low correlation with extracellular volume (r = 0.28; P = .003). A total of 109 events (53%) were recorded during a follow-up of 38 months ± 29. Participants with a GLS above the median had higher event rates (log-rank test, P < .001). By multivariable Cox regression analysis, GLS remained independently associated with outcome (hazard ratio, 1.06 per 1% strain increase; 95% confidence interval: 1.01, 1.11; P = .03) when corrected for risk factors including age, diabetes, renal function, N-terminal pro-b-type natriuretic peptide serum concentration, and right ventricular size and function. Conclusion In participants with heart failure with preserved ejection fraction, global longitudinal strain at cardiovascular MRI was correlated with extracellular volume by T1 mapping and was associated with cardiovascular events. © RSNA, 2020 Online supplemental material is available for this article.

ROLE OF MRI T2 MAPPING IN ASSESSMENT OF ARTICULAR KNEE CARTILAGE IN OSTEOARTHRITIS

Background: T2 mapping of hyaline cartilage is an imaging technique for the qualitative and quantitative detection of thecartilage providing convincing color mapping and quantitative detection of the cartilage mainly regarding architecture and changes in water content, proteoglycan, and collagen matrix ultra-structure associated with early cartilage degeneration.Aim Of Work: This work aims at elucidating the role of MRI complementary T2 mapping in assessment of articular knee cartilage for improving sensitivity of early detection of Osteoarthritis. Also, compare the articular cartilage T2 relaxation values in normal subjects and patients with osteoarthritis. Patients And Methods: This prospective case-control study wasapproved by the Ethical Committee of Scientific Research in Ain Shams University, and the informed consent was obtained. The material of this study included sixty (60) subjects, divided into two groups, 50 patients (symptomatic group: 33 men and 17 women) with clinical evidence of osteoarthritis, and 10 normal control group (asymptomatic group 8 men and 2 women) were included in this study, with their ages ranged between 19-75 years. All patients and controls underwent MR imaging of the knee joint. MR imaging was performed at 1.5 Tesla by using a routine protocol with the addition of a sagittal, coronal, or axial T2 mapping sequence or all. The standard imaging planes of the knee were evaluated with articular cartilage assessment as intact or not. Thereafter, these standard planes were evaluated together with T2 maps and articular cartilage was again assessed as of normal (<48ms) or elevated (≥48ms) T2 value in terms of milliseconds. Generalized estimating equation models were used to compare the sensitivity and specificity of the routine MR imaging protocol and T2 maps. Results: Both sensitivities and specificities were 82% and 100%, respectively, for the routine MR protocol alone and 100% and 90% after the addition of the T2 mapping to the routine MR protocol. The addition of T2 maps to the routine MR imaging protocol significantly improved the sensitivity (Binary Diagnostic test, p = 0.01). AComparison between patients and controls as regards T2 values showed a highly statistically significant difference (Independent TTest, P<0 .001). Conclusion: A combination of both morphological and T2 mapping MRI, together with clinical evaluation represents a desirable multi-modal approach to the diagnosis of osteoarthritis. T2 mapping, as a biochemically sensitive MRI sequence of the knee improves sensitivity from 82% to 100% to detect early structural degeneration with better diagnostic information in the knee articular cartilage.

SAT-540 Primary Aldosteronism Represents Earlier Myocardial Fibrosis Than Essential Hypertension by T1 Mapping

Introduction:Primary aldosteronism (PA) is associated with cardiovascular disease and has increased cardiovascular morbidity. Several studies had demonstrated that PA shows more serious myocardial fibrosis compared with essential hypertension (EH) using late Gadolinium-enhanced (LGE) imaging [1, 2]. However, the early myocardial change may not be detected by LGE. Recently, cardiac MRI T1 mapping emerged to be a sensitive technique in detecting early changes of myocardium quantitatively. Our study aimed to demonstrate the early myocardial change in PA patients by applying the T1-mapping technique.Method:81 (male: 25; age: 48±12 years) PA[3] and 44 (male: 21; age: 47±14 years) EH patients diagnosed by the Department of Endocrinology and metabolism according to the 2016 TES guidelines for PA were recruited from September 2018 to May 2019. All the subjects underwent cardiac MRI examinations on a 3T MRI scanner (MAGNETOM Trio a Tim System, Siemens Healthcare, Erlangen, Germany), including steady-state free-precession (SSFP) cine imaging and modified Look-Locker inversion recovery (MOLLI) imaging for T1 mapping. Functional parameters were obtained from cine images by the Argus software (Siemens Healthcare, Erlangen, Germany).The mid-ventricular native T1 value was acquired using the QMass software (Medis, Leiden, The Netherlands). Native T1 value and cardiac function parameters were analyzed between the two groups. Differences of continuous variables were analyzed by Student’s t-test or Mann-Whitney U-test, and the relationships between native T1 value and physiological variables were analyzed by multiple linear regression method.Results:The age (PA: 48±12 years vs EH: 47±14 years; p=0.720) and BMI (PA: 25.06±3.73 vs EH: 25.17±2.83; P=0.874) between two groups had no significant differences. The PA group had a significant higher aldosterone/renin ratio (ARR) than those in the EH group (114.6 (48.7-474.8)ng/dl:ng/ml.h vs 7.6 (4.2-13.8) ng/dl:ng/ml.h; p<0.001). All functional parameters including LVEDVI (PA: 78.66 (72.4-90.6) ml/m2 vs EH: 75.8 (64.3-85.8) ml/m2; p=0.054); LVESVI (PA: 31.7 (26.2-38.4) ml/m2 vs EH: 29.3 (24.9-36.2) ml/m2; p=0.152); LVEF (PA: 59.9 (53.3-65.0)% VS EH: 59.2(55.3-65.6)%; p=0.679); LVmassi (PA: 58.5(47.7-67.7) g/m2 vs EH: 54.9 (47.6-60.1) g/m2; p=0.463) had no differences between the two groups. However, native T1 values were higher in PA group than those in EH group (1227±40ms vs 1203±45ms). The multiple linear regression analysis showed that gender (Beta=-27.678, p<0.001) and PA (Beta=-17.287, p=0.031) were independently related to the native T1 values.Conclusion:PA patients represent more severe and earlier myocardium damage and this might be related to cardiovascular morbidity. The T1-mapping technique in cardiac MRI is more sensitive to evaluate the left ventricular function and to detect the myocardial fibrosis in PA patients.

Prevalence of medial meniscus extrusion in elderly persons -the bunkyo health study

Purpose: Meniscus function is important in knee osteoarthritis (knee OA), and aging-related dysfunction of meniscus is becoming a risk factor for the development and progression of knee OA. Recently, meniscal malposition, especially medial meniscus extrusion (MME), in addition to conventional meniscal damage is also attracting attention, and it has been shown that MME plays an important role for the incidence and progression of knee OA. However, the mechanism of the developmental process of MME is still remained unclear. In our recent study using T2 mapping MRI, MME was found in all cases with early stage knee OA patients who did not have meniscal lesion or tear. We also demonstrated that osteophyte consists of cartilage- and bone-parts, as osteophyte is formed by the process similar to the endochondral ossification. When cartilage-part of osteophyte, in addition to bone-parts, was evaluated, MME was coincided with the medial tibial osteophyte width in patients with early- to primary-stage knee OA (Arthritis Res Ther, 19:201, 2017). However, there is no report of the prevalence of MME in the general elderly cohort data. The purpose of this study was to examine the prevalence of MME among the elderly using a population-based cohort data. Methods: A total of 1,630 subjects aged between from 65 to 84 years of age participated in the Bunkyo Health Study during from November 2015 to September 2018. 1,191 subjects underwent both the plain radiograph in the standing position and MRI on knee joint (Hitachi, 0.3T). As 46 among 1,191 who showed lateral type of knee OA (femoro-tibial angle <173) were excluded, the remaining 1145 subjects (55.7% females, 72.9 years of age on average) were analyzed. A radiographic severity of knee OA was classified into four grades using the Kellgren-Lawrence (K/L) classification. FTA and medial joint space width (JSW) were measured with X-ray. The MME was evaluated according to whole organ magnetic resonance imaging score (WORMS). In addition, the position of the medial meniscus was measured for anomalies (1 mm or more was regarded as a position error), and 3 mm or more was defined as MME. A p-value less than 5% was considered to be statistically significant. All analyses were undertaken using the statistical package SPSS. Results: The severity of radiographic medial knee OA of the subjects in the present study was 16 (1.4%) for K/L 1, 986 (86.1%) for K/L 2, 106 (9.3%) for K/L 3, and 37 (3.2%) for K/L 4. Abnormal position of medial meniscus was detected in almost all cases (1,139 persons, 99.5%, 4.4±2.1mm on average). The MME was detected 842 persons (73.5%). Prevalence by generation of the MME was increased with each generation (p<0.001): 70.7% for 65-70 years of age, 74.1% for 70-75 years of age, 74.7% for 75-80 years of age, 79.9% >80 years of age. Abnormal position of the medial meniscus was associated with FTA (r = 0.18 p <0.001), JSW (r = -0.20 p <0.001), and age (r = 0.13 p <0.001). Conclusions: In the present population-based study, most of the subjects among the middle aged and elderly populations who did not require the medical treatment for their knee joint showed the K/L grade 2 of radiographic knee OA change. In elderly people over the age of 65 in Japan, most of the medial meniscus had an abnormal position, and more than 70% of medial meniscus categorizes to MME. In addition, the probability of MME becomes higher with age.

Association between myocardial hypoxia and fibrosis in hypertrophic cardiomyopathy: analysis by T2* BOLD and T1 mapping MRI.

We assessed whether an association exists between myocardial oxygenation and myocardial fibrosis in patients with hypertrophic cardiomyopathy (HCM), using blood-oxygen-level-dependent (BOLD) T2* cardiac magnetic resonance imaging (T2*-CMR) and T1 mapping. T1 mapping and T2*-CMR data were collected from 55 HCM patients using a 3-T MR and were prospectively analyzed. T2*-CMR was conducted using the black blood, breath-hold, multi-echo, and gradient echo sequence. Over 10min, inhalation of oxygen at the flow rate of 10L/min, T2* for mid-septum was measured following room-air and oxygen inhalation, and ΔT2* ratio (T2*oxy-T2*air/T2*air, %) was calculated. During pre- and post-gadolinium enhancement, native T1 (ms) and extracellular volume fractions (ECV, %) were calculated at sites same as the T2* measurement. Hypoxia was defined as the segment with an absolute value of the ΔT2* ratio ≥ 10%. ΔT2* ratio was significantly higher for segments with native T1 ≥ 1290ms than those with native T1 < 1290ms (21 ± 32% vs. 8 ± 6%, p = 0.005). ΔT2* ratio was also significantly higher for segments with ECV ≥ 28% than those with ECV < 28% (21 ± 32% vs. 8 ± 8%, p = 0.0003). ROC curve analysis revealed that ΔT2* ratio could detect segments with native T1 ≥ 1290ms and ECV ≥ 28% and c-statistics of 0.72 and 0.79. According to the multivariate logistic regression analysis results, ECV is an independent factor in hypoxia (odds ratio, 1.47; 95% confidence interval, 1.02-2.13; p < 0.05). Analysis of BOLD T2*-CMR and T1 mapping revealed that ECV is strongly associated with ΔT2* ratio, suggesting that the onset of myocardial fibrosis is related to hypoxia in HCM patients. Our study was approved by the ethics committee of our institute (#4036, registered on 21 July 2016) KEY POINTS: • Analysis of ΔT2* ratio and ECV with BOLD-T2* and T1 mapping revealed a strong association between myocardial fibrosis and hypoxia in HCM patients.

Lung T1 mapping magnetic resonance imaging in the assessment of pulmonary disease in children with cystic fibrosis: a pilot study.

Assessment tools for early cystic fibrosis (CF) lung disease are limited. Detecting early pulmonary disease is crucial to increasing life expectancy by starting interventions to slow the progression of the pulmonary disease with the many treatment options available. To compare the utility of lung T1-mapping MRI with ultrashort echo time (UTE) MRI in children with cystic fibrosis in detecting early stage lung disease and monitoring pulmonary exacerbations. We performed a prospective study in 16 children between September 2017 and January 2018. In Phase 1, we compared five CF patients with normal spirometry (mean 11.2years) to five age- and gender-matched healthy volunteers. In Phase 2, we longitudinally evaluated six CF patients (median 11years) in acute pulmonary exacerbation. All children had non-contrast lung T1-mapping and UTE MRI and spirometry testing. We compared the mean normalized T1 value and percentage lung volume without T1 value in CF patients and healthy subjects in Phase 1 and during treatment in Phase 2. We also performed cystic fibrosis MRI scoring. We evaluated differences in continuous variables using standard statistical tests. In Phase 1, mean normalized T1 values of the lung were significantly lower in CF patients in comparison to healthy controls (P=0.02) except in the right lower lobe (P=0.29). The percentage lung volume without T1 value was also significantly higher in CF patients (P=0.006). UTE MRI showed no significant differences between CF patients and healthy volunteers (P=0.11). In Phase 2, excluding one outlier case who developed systemic disease in the course of treatment, the whole-lung T1 value increased (P=0.001) and perfusion scoring improved (P=0.02) following therapy. We observed no other significant changes in the MRI scoring. Lung T1-mapping MRI can detect early regional pulmonary CF disease in children and might be helpful in the assessment of acute pulmonary exacerbations.

Splenic T1ρ as a noninvasive biomarker for portal hypertension.

There is a need for noninvasive methods for the diagnosis and monitoring of portal hypertension (PH). To 1) assess the correlation of liver and spleen T1 and T1ρ measurements with portal pressures in patients with chronic liver disease, and 2) to compare the diagnostic performance of the relaxation parameters with radiological assessment of PH. Prospective. Twenty-five patients (M/F 16/9, mean age 56 years, range 21-78 years) undergoing portal pressure (hepatic venous pressure gradient [HVPG]) measurements. 1.5T abdominal MRI scan, including T1ρ and T1 mapping. Liver and spleen T1ρ and T1 , radiological PH score, and (normalized) spleen length were evaluated. Spearman correlation of all MRI parameters with HVPG was assessed. The diagnostic performance of the assessed parameters for prediction of PH (HVPG ≥5 mmHg) and clinically significant PH (CSPH, HVPG ≥10 mmHg) was determined by receiver operating characteristic (ROC) analysis. The mean HVPG measurement was 7.8 ± 5.3 mmHg (PH, n = 18 [72%] including CSPH, n = 9 [36%]). PH score, (normalized) spleen length and spleen T1ρ significantly correlated with HVPG, with the strongest correlation found for spleen T1ρ (r = 0.613, P = 0.001). Spleen T1ρ was the only parameter that showed significant diagnostic performance for assessment of PH (area under the curve [AUC] 0.817, P = 0.015) and CSPH (AUC = 0.778, P = 0.024). Normalized spleen length also showed significant diagnostic performance for prediction of CSPH, with a slightly lower AUC (= 0.764, P = 0.031). The radiological PH score, T1ρ and T1 of the liver and T1 of the spleen, did not show significant diagnostic performance for assessment of CSPH (P > 0.075). Spleen T1ρ showed a significant correlation with portal pressure and showed improved diagnostic performance for prediction of CSPH compared to radiological assessment. These initial results need confirmation in a larger cohort. 1 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2020;52:787-794.

Regions of High Dominant Frequency in Chronic Atrial Fibrillation Anchored to Areas of Atrial Fibrosis.

Regions within the atria with sustained rapid reentrant or focal activity have been defined as a mechanism of persistent atrial fibrillation (AF). However, the mechanism behind the anchoring of these sites and their stability over time is unknown. We tested the hypothesis that fibrosis anchors sites of high frequency activation during AF and that these sites can be non-invasively determined using cardiac T1 Mapping with MRI. A canine rapid atrial paced model of persistent AF was used (n=12, including 6 controls) for the study. Whole heart T1 Mapping was performed prior to an electrical mapping study. Spatial maps of high dominant frequency (DF) probability were constructed to determine stability of the highest DF sites. These sites were then correlated with fibrotic regions determined by T1 Mapping. The chronic AF animals had at least one site of stable, high DF for at least 22.5 (75%) of 30 minutes of AF. Regions of stable high DF bordered regions of fibrosis as determined by T1 Mapping MRI 82% of the time (p<0.05). Heterogeneous atrial remodeling, specifically fibrosis, arising from chronic AF may provide a substrate that anchors sites of high DF. Cardiac T1 Mapping with MRI may determine such sites non-invasively.

Histological Grade and Magnetic Resonance Imaging Quantitative T1rho/T2 Mapping in Osteoarthritis of the Knee: A Study in 20 Patients.

BackgroundMagnetic resonance imaging (MRI) of osteoarthritis (OA) of the knee is a preoperative method of joint assessment. Histology of the joint is invasive and performed after surgery. T1rho/T2 MRI mapping is a new preoperative method of quantifying joint changes. This study aimed to analyze and compare the histological changes in the joint cartilage with the use of quantitative T1rho/T2 MRI mapping in patients with OA of the knee.Material/MethodsTwenty patients with OA of the knee (20 knees) underwent preoperative MRI with T1rho mapping, T2 mapping, T1-weighted, and T2-weighted fat-suppressed MRI sequences. The degree of OA of the knee on MRI was graded according to the Osteoarthritis Research Society International (OARSI) criteria and the Kellgren-Lawrence grading system. Histological grading of OA used the OARSI criteria. Four tibiofemoral condyles were assessed histologically, and the degree of cartilage destruction was determined using the OARSI criteria. Two investigators performed cartilage segmentation for T1rho/T2 values.ResultsHistology of the four knee joint condyles confirmed mild to severe OA. The histology of the cartilage thickness (P<0.001) and the MRI findings of the distal medial condyle (P<0.00) were significantly different from the other three knee joint condyles. The T2 and T1rho values of each condyle were significantly correlated with the histological grade (II–IV) of the joint condyles, including the cartilage volume, cartilage defects, thickness, and bone lesions (P<0.05).ConclusionsIn 20 patients with OA of the knee, preoperative T2/T1rho MRI identified Grade II–IV OA changes in the joint.

Investigation of myocardial extracellular volume fraction in heart failure patients using iodine map with rapid-kV switching dual-energy CT: Segmental comparison with MRI T1 mapping

PurposeTo measure myocardial extracellular volume fraction (ECV) for each region or segment using iodine density image (IDI) with single-source dual-energy computed tomography (DECT) and compare the results with an MRI T1 mapping approach. Materials and methodsFor this prospective study, 79 consecutive heart failure patients referred for MRI were included and 23 patients (14 men, 63 ± 14 years) who underwent both MRI and late contrast enhancement DECT following coronary CT angiography were evaluated. CT-ECV was computed from IDI using late acquisition projection data. MR-ECV was computed from native and post-contrast T1 maps using non-rigid image registration for segments with evaluable image quality from 3.0-T MRI. Regional CT-ECV and MR-ECV were measured based on 16-segment models. CT-ECV and MR-ECV were compared using Pearson correlations. Agreement among methods was assessed using Bland-Altman comparisons. ResultsIn the 368 segments, although all segments were evaluable on IDI, 37 segments were rated as non-evaluable on T1 maps. Overall, 331 segments were analyzed. Mean CT-ECV and MR-ECV were 31.6 ± 9.1 and 33.2 ± 9.1, respectively. Strong correlations were seen between CT-ECV and MR-ECV for each region, as follows: all segments, r = 0.837; septal, r = 0.871; mid-septal, r = 0.895; anterior, r = 0.869; inferior, r = 0.793; and lateral, 0.864 (all p < 0.001). Differences between CT-ECV and MR-ECV were as follows: all segments, 1.13 ± 4.98; septal, −1.51 ± 4.37; mid-septal, −1.85 ± 4.22; anterior, 2.54 ± 4.89; inferior, 1.2 ± 5.78; and lateral, 2.65 ± 3.98. ConclusionECV using DECT and from cardiac MRI showed a strong correlation on regional and segmental evaluations. DECT is useful for characterizing myocardial ECV changes as well as MRI.

An extensible software platform for interdisciplinary cardiovascular imaging research

Background and objectiveCardiovascular imaging is an exponentially growing field with aspects ranging from image acquisition and analysis to disease characterization, and evaluation of therapy approaches.The transfer of innovative new technological and algorithmic solutions into clinical practice is still slow. In addition to the verification of solutions, their integration in the clinical processing workflow must be enabled for the assessment of clinical impact and risks. The goal of our software platform for cardiac image processing – CAIPI – is to support researchers from different specialties such as imaging physics, computer science, and medicine by a common extensible platform to address typical challenges and hurdles in interdisciplinary cardiovascular imaging research. It provides an integrated solution for method comparison, integrated analysis, and validation in the clinical context. The interface concept enables a combination with existing frameworks that address specific aspects of the pipeline, such as modeling (e.g., OpenCMISS, CARP) or image reconstruction (Gadgetron). MethodsIn our platform, we developed a concept for import, integration, and management of cardiac image data. The integration approach considers the spatiotemporal properties of the beating heart through a specific data model. The solution is based on MeVisLab and provides functionalities for data retrieval and storage. Two types of plugins can be added. While ToolPlugins usually provide processing algorithms such as image correction and segmentation, AnalysisPlugins enable interactive data exploration and reporting. GUI integration concepts are presented for both plugin types. We developed domain-specific reporting and visualization tools (e.g., AHA segment model) to enable validation studies by clinical experts. The platform offers plugins for calculating and reporting quantitative parameters such as cardiac function, which can be used to, e.g., evaluate the effect of processing algorithms on clinical parameters. Export functionalities include quantitative measurements to Excel, image data to PACS, and STL models to modeling and simulation tools. ResultsTo demonstrate the applicability of this concept both for method development and clinical application, we present use cases representing different problems along the innovation chain in cardiac MR imaging.Validation of an image reconstruction method (MRI T1 mapping)Validation of an image correction method for real-time 2D-PC MRIComparison of quantification methods for blood flow analysisTraining and integration of machine learning solutions with expert annotationsClinical studies with new imaging techniques (flow measurements in the carotid arteries and peripheral veins as well as cerebral spinal fluid). ConclusionThe presented platform can be used in interdisciplinary teams, in which engineers or data scientists perform the method validation, followed by clinical research studies in patient collectives. The demonstrated use cases show how it enables the transfer of innovations through validation in the cardiovascular application context.

The value of gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid enhanced T1 mapping MRI in the quantitative evaluation of hepatic fibrosis in patients with hepatitis B

Objective To investigate the quantitative evaluation efficiency of gadolinium- ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) enhanced T1 mapping in staging hepatic fibrosis caused by viral hepatitis B. Methods One hundred and fifty patients with chronic hepatitis B were prospectively enrolled in Shanghai Public Health Clinical Center, Fudan University from August 2016 to August 2018.These patients underwent liver aspiration biopsy were divided into four subgroups: S1 (n=38), S2 (n=30), S3 (n=33), S4 (n=49) according to Scheuer-Ludwig scoring system. Non-enhanced and Gd-EOB-DTPA-enhanced MRI were performed in all subjects. Look-Locker sequences were performed to acquire T1 mapping of pre and post-contrast at 20 minutes after Gd-EOB-DTPA administration. The T1 value after 20 minutes of Gd-EOB-DTPA administration (T1 20 min), the reduction rate of T1 value (ΔT1 20 min%), the increase of 1/T1 value (ΔR1 20 min%) were measured and calculated. The one-way ANOVA was applied to compare the difference in T1 20 min, ΔT1 20 min%, ΔR1 20 min% of various fibrosis stages. ROC curves were used to assess the efficacy of T1 20 min, ΔT1 20 min%, ΔR1 20 min% for diagnosing ≥ S2, ≥ S3, ≥ S4. P<0.05 was considered to be statistically significant. Results The T1 20 min raised with fibrosis stage increased, ΔT1 20 min% and ΔR1 20 min% reduced with fibrosis stage increased. Areas under the curves of T1 20 min, ΔT1 20 min%, ΔR1 20 min% for diagnosing ≥ S2 were 0.844, 0.905, 0.869; and diagnosing ≥ S3 were 0.832, 0.907, 0.862; and diagnosing ≥ S4 were 0.853, 0.897, 0.873, respectively. The diagnostic efficiency of ΔT1 20 min% was the best. Conclusion Gd-EOB-DTPA-enhanced T1 mapping could be regarded as a reliable diagnostic tool for the evaluation of hepatic fibrosis caused by viral hepatitis B. Key words: Hepatic fibrosis; Magnetic resonance imaging; Gadoxetate acid disodium; T1 mapping

MRI T1 Mapping in Hypertrophic Cardiomyopathy: Evaluation in Patients Without Late Gadolinium Enhancement and Hemodynamic Obstruction

Background The value of native myocardial T1 mapping and extracellular volume (ECV) fraction in patients who have hypertrophic cardiomyopathy (HCM) but no late gadolinium enhancement (LGE) and no hemodynamic obstruction are currently unknown. Purpose To evaluate myocardial fibrosis in patients with nonobstructive HCM and no LGE by using native myocardial T1 mapping and ECV fraction and to study their relationships to left ventricular (LV) function and LV hypertrophy. Materials and Methods Patients with HCM who underwent cardiac MRI between 2012 and 2015 were retrospectively evaluated. Patients were included if they had no LGE at MRI, LV ejection fraction greater than or equal to 45%, and no LV outflow tract obstruction. Healthy participants had similar age and sex distribution. Native myocardial T1 and ECV were measured with MRI. Results A total of 258 patients with HCM (mean age ± standard deviation, 49 years ± 15; 74% men) and 122 healthy participants (mean age, 50 years ± 14; 76% men) were evaluated. Native myocardial T1 was longer and ECV fraction was higher in the patients with HCM relative to the healthy participants (mean native T1, 950 msec ± 48 vs 913 msec ± 46; mean ECV, 24.5% ± 2.8 vs 23.0% ± 2.7; both P < .001). Maximum T1 and ECV values correlated strongly with LV mass index for the entire patient cohort with HCM (both r = 0.86; P < .001) and for the subgroups (r = 0.86 and 0.85 for interventricular septal group and r = 0.88 and 0.86 for apical group; all P < .001). Conclusion Prolonged myocardial T1 and elevated extracellular volume in hypertrophic cardiomyopathy suggests diffuse myocardial fibrosis, even in the absence of regionally apparent late gadolinium enhancement and hemodynamic obstruction, and is associated with left ventricular hypertrophy. © RSNA, 2019 See also the editorial by Bluemke and Lima in this issue.

Tissue characterisation and myocardial mechanics using cardiac MRI in children with hypertrophic cardiomyopathy.

Distinguishing between hypertrophic cardiomyopathy and other causes ofleft ventricular hypertrophy can be difficult in children. We hypothesised that cardiac MRI T1 mapping could improve diagnosis of paediatric hypertrophic cardiomyopathy and that measures of myocardial function would correlate with T1 times and extracellular volume fraction. Thirty patients with hypertrophic cardiomyopathy completed MRI with tissue tagging, T1-mapping, and late gadolinium enhancement. Left ventricular circumferential strain was calculated from tagged images. T1, partition coefficient, and synthetic extracellular volume were measured at base, mid, apex, and thickest area of myocardial hypertrophy. MRI measures compared to cohort of 19 healthy children and young adults. Mann-Whitney U, Spearman's rho, and multivariable logistic regression were used for statistical analysis. Hypertrophic cardiomyopathy patients had increased left ventricular ejection fraction and indexed mass. Hypertrophic cardiomyopathy patients had decreased global strain and increased native T1 (-14.3% interquartile range [-16.0, -12.1] versus -17.3% [-19.0, -15.7], p < 0.001 and 1015 ms [991, 1026] versus 990 ms [972, 1001], p = 0.019). Partition coefficient and synthetic extracellular volume were not increased in hypertrophic cardiomyopathy. Global native T1 correlated inversely with ejection fraction (ρ = -0.63, p = 0.002) and directly with global strain (ρ = 0.51, p = 0.019). A logistic regression model using ejection fraction and native T1 distinguished between hypertrophic cardiomyopathy and control with an area under the receiver operating characteristic curve of 0.91. In this cohort of paediatric hypertrophic cardiomyopathy, strain was decreased and native T1 was increased compared with controls. Native T1 correlated with both ejection fraction and strain, and a model using native T1 and ejection fraction differentiated patients with and without hypertrophic cardiomyopathy.

MRI native T1 and T2 mapping of myocardial segments in hypertrophic cardiomyopathy: tissue remodeling manifested prior to structure changes.

The aim of this study was to examine the local myocardial segments in hypertrophic cardiomyopathy (HCM) by MRI T1 and T2 mapping, and to investigate how tissue remodeling correlates with structural and functional remodeling in HCM. 47 patients with HCM and 19 healthy volunteers were enrolled in this study. All subjects underwent cardiac MRI at 3.0 T. Native T1 and T2 values, end-diastolic wall thickness (EDTH), and percentage of systolic wall thickening (PSWT) were assessed in the left ventricular segments according to the American Heart Association model. Myocardial segments were categorized as normal, non-hypertrophic, mild-hypertrophic, moderate-hypertrophic, and severe-hypertrophic based on EDTH. The difference among all five groups, and the correlation between native T1 and T2 values, EDTH, and PSWT were evaluated. Native T1 and T2 values were significantly elevated in both non-hypertrophic and hypertrophic segments of HCM patients compared to controls (both p < 0.001). PSWT was preserved in non-hypertrophic segments (p = 0.838), while significantly impaired (p < 0.001) in hypertrophic segments. Native T1 value of severe hypertrophic segments in HCM was significantly higher than segments of mild and moderate hypertrophy (p < 0.05). In HCM patients, the non-hypertrophic myocardial segments already demonstrated significantly elevated T1 and T2 values, despite normal wall thickness and preserved contraction function. The finding suggests that tissue remodeling may precede morphological and functional remodeling in HCM. MRI native T1 and T2 mapping can provide additional value for HCM diagnosis at an early stage. Myocardial tissue remodeling, as detected by MRI native T1 and T2 mapping, occurs earlier than morphological and functional changes in HCM patients.

T1 Mapping and Cardiac MRI in the Detection of Cardiac Toxicity from Radiotherapy

T1 Mapping and Cardiac MRI in the Detection of Cardiac Toxicity from Radiotherapy

Effect of physical therapy on early knee osteoarthritis with medial meniscal posterior tear assessed by MRI T2 mapping and 3D-to-2D registration technique: A prospective intervention study

Objectives: The purpose of this study was to verify that exercise aimed at improving knee kinematics in early-stage knee osteoarthritis (OA) patients with medial meniscus posterior root tears (MMPRTs) reduces knee adduction angle during gait and prevents rapid cartilage degeneration in the medial compartment of the knee.Methods: Subjects were randomly assigned to an adapting alignment exercise (AAE) group, with the goal of improving knee kinematics, and a muscle training and exercise (MTE) group. Before the start of the six-month intervention and following its completion, we performed an analysis of knee kinematics during gait using a 3D-to-2D registration technique and identified the area of cartilage degeneration using MRI T2 mapping.Results: The amount of change between pre- and post-intervention measurements of the maximum angle of adduction was 0.48° (95% CI: −0.14, 1.09) in the MTE group and −0.40° (−0.84, 0.04) in the AAE group (p = .039). The amount of change in the area of cartilage degeneration according to MRI T2 mapping expressed as MTE/AAE group was 7.7 mm2 (−0.4, 15.8)/−2.7 mm2 (−10.8, 5.3) at the posterior knee (p = .043).Conclusion: AAE could be a potential treatment method that improves the natural course of knee OA with MMRPTs.

The value of contrast-enhanced T1 mapping technique in differentiating recurrence and radiation necrosis of brain metastases after gamma knife treatment

Objective To explore the value of contrast-enhanced T1 mapping technique in differentiating between recurrence and radiation necrosis of brain metastases after gamma knife treatment. Methods From March 2016 to June 2017,56 patients with brain metastases treated by gamma knife and confirmed by pathology or follow-up in Shandong Provincial Hospital were prospectively collected. Routine MRI and contrast-enhanced T1 mapping sequence scan were performed. T1 value was obtained 5 mins (T1 5min) and 60 mins (T1 60min) after injection of contrast agent. The Differences betweenT1 60 min and T1 5 min (T1differ) was calculated,and relative cerebral blood volume (rCBV) value was obtained. Patients were divided into radiation necrosis group and tumor recurrence group according to imaging follow-up results or pathological results. Two-sides unpaired t test was used to compare the differences in T1 5 min,T1 60 min,T1 differ and rCBV between the 2 groups. Pearson correlation analysis was used to evaluate the correlation between T1 differ and rCBV,and the receiving operating curve (ROC) was used to evaluate the diagnostic efficiency of MRI quantitative parameters,and Z test was used to compare the differences of area under curve (AUC) between T1 differ and rCBV values. Results Of the 56 patients,27 had tumor recurrence and 29 had radiation necrosis. The differences in T1 5 min,T1 60 min,T1 differ and rCBV between the 2 groups was statistically significant (P<0.05). T1 differ and rCBV values were significantly correlated,r=0.58,P<0.01. The differential diagnosis of AUC between radiation necrosis and tumor recurrence were 0.66,0.73,0.97 and 0.95 respectively in T1 5min,T1 60 min,T1 differ and rCBV,and there was no significant differences between AUC in T1 differ and rCBV (P=0.274). Conclusion The contrast-enhanced T1 mapping image can be used for differential diagnosis between radiation necrosis and recurrence after gamma knife treatment of brain metastases. T1 differ value has high differential efficiency. Key words: Brain neoplasms; Neoplasm metastasis; T1 mapping; Radiation necrosis; Recurrence of tumor; Gamma knife treatment

Arthroscopic Treatment of Patellar and Trochlear Cartilage Lesions with Matrix Encapsulated Chondrocyte Implantation versus Microfracture: Quantitative Assessment with MRI T2-Mapping and MOCART at 4-Year Follow-up.

Seventeen patients aged 18 to 55 years with symptomatic full-thickness cartilage lesions on either patella or trochlea were treated with matrix autologous chondrocyte implantation (MACI) or microfracture (MF). Both procedures combined with unloading/realigning techniques. Clinical assessment and T2-mapping were evaluated at 48-months. Clinically results from pre-op to 48-months improved significantly in MACI and MF for Lysholm (p = 0.001, p = 0.001), IKDC-S (p = 0.001, p = 0.002), KOOS-P (p = 0.000, p = 0.002), KOOS-DLA (p = 0.002, p = 0.003), KOOS-Sports/Rec (p = 0.000, p = 0.004), KOOS-QoL (p = 0.000, p = 0.003), KOOS-symptoms (p = 0.001, p = 0.020), and Kujala (p = 0.000, p = 0.01), respectively. Tegner was significant between baseline and 48 months only for MACI (p < 0.008) compared with MF (p = 0.25). No significant difference was observed between groups for any score at 3, 12, 24, and 48-months (p > 0.05). T2-mapping values improved significantly over time in MACI compared with MF at 24 months (39.35 vs. 50.44, p = 0.007) and 48 months (36.54 vs. 48.37, p = 0.005). When comparing control values to MACI at 12-m (p = 0.714), 24-m (p = 0.175), and 48-m (p = 0.097), no significant difference was found. MOCART (Magnetic Resonance Observation of Cartilage Repair Tissue) score comparison gave no statistical difference between groups. Clinically both techniques improved significantly over time. However, quantitative assessment showed that only newly formed tissue with MACI technique improves significantly since 12-months and maintains stable values compared with native cartilage until 48-month follow-up. MF results were never comparable to those native values. Level of evidence II.

Osteophytes formation processes in early stage knee osteoarthritis in human

Purpose: Reduction of ADL by osteoarthritis of the knee (knee OA) is a major factor threatening healthy life expectancy. Thus, clarification of the pathology of knee OA is desired. We reported that cartilage part of osteophyte could be detected using T2 mapping MRI and medial meniscal extrusion (MME) was associated with medial tibial osteophyte evaluated by T2 mapping MRI in early-stage knee OA (Arthritis Res Ther, 19:201, 2017). However, there is no report showing cartilage part of osteophytes in early stage knee OA in human, histologically. The aim of this study was to investigate the morphological feature of osteophytes in human knee OA using cadavers. Methods: All cadavers were from persons who had donated their bodies for medical education and research to our university. Prior to donation, written consent was obtained from the individuals and families. The protocol for the present research project was approved by the Ethics Committee of our university. Fourteen left legs were collected from embalmed Japanese cadavers (3 males, 11 females; average age, 83.3±8.2 years of age), which were dissected by medical students in the gross anatomy course at Juntendo University School of Medicine. Knee joint was dissected out proximal and distal 10cm from the knee articular surface after skin removal. Anteroposterior view radiographs were taken and then evaluated according to the Kellgren-Lawrence (K/L) classification. Then, the patella and muscle were removed and the 2 cm width of medial parts of the knee joint remaining the medial collateral ligament were collected. They were fixed in 10% neutral buffered formalin, decalcified, and embedded in paraffin. The samples were cut into sections and stained with safranin-O and fast green. The histological features of medial tibial plateau (MTP) was quantified by histological grading scores. The cartilage degradation score used in the present study was the modified Mankin score (0-18) (Mankin, JBJS, 1971). The osteophyte formation score used in the present study was a score for its maturity with 5 degrees (0-4; grade 0: no osteophyte like lesion, grade 1: pre-cartilagious lesion, grade 2: predominantly cartilaginous, grade 3: mixed cartilage and bone, grade 4: predominantly bone), which was modified by the score for the evaluation of osteophyte in mouse model, as previously reported (Kamekura et al., Osteoarthritis Cartilage, 2005). Results: The severities of radiographic knee OA of the subjects in the present study were 7 (50.0%) for K/L grade 1, 5 (37.7%) for K/L grade 2, 2 (14.3%) for K/L grade 4, respectively. The cartilage degradation scores of the subjects were 4.1 [standard deviation (SD): 1.5] for K/L grade 1, 5.2 (1.3) for K/L grade 2, 15.0 (3.0) for K/L grade 4, respectively. Osteophytes were observed in all the samples of the subjects, regardless of the radiographic severity of knee OA. The osteophyte scores of the subjects were 7 (50.0%) for grade 1, 3 (21.4%) for grade 2, 2 (14.3%) for grade 3, and 2 (14.3%) for grade 4, respectively (Fig. 1). The histological sections with grade 4 of osteophytes were consisted of proliferative, pre-hypertrophic, hypertrophic, and ossification zones, while those with grade 1 were consisted of reduplication of synovial tissues. Conclusions: The histological examinations showed that osteophytes were existed in all the samples of the subjects, which showed the radiographic knee OA changes not only with K/L grade 2 to 4 but also with K/L grade 1. The developmental processes of the osteophyte in knee OA in human were similar to those observed in the growth plate in the murine model, which is the process similar to the endochondral ossification.