scholarly journals Quantitative analysis of the ACL and PCL using T1rho and T2 relaxation time mapping: an exploratory, cross-sectional comparison between OA and healthy control knees

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Chanuka D. S. Ranmuthu ◽  
James W. MacKay ◽  
Victoria A. Crowe ◽  
Joshua D. Kaggie ◽  
Dimitri A. Kessler ◽  
...  
Keyword(s):  
Posterior Cruciate Ligament ◽  
Repeated Measures ◽  
T2 Mapping ◽  
Cruciate Ligament ◽  
Intraclass Correlation ◽  
Relaxation Times ◽  
Fast Spin Echo ◽  
Human Populations ◽  
Cruciate Ligaments ◽  
T2 Relaxation

Abstract Background Quantitative magnetic resonance imaging (MRI) methods such as T1rho and T2 mapping are sensitive to changes in tissue composition, however their use in cruciate ligament assessment has been limited to studies of asymptomatic populations or patients with posterior cruciate ligament tears only. The aim of this preliminary study was to compare T1rho and T2 relaxation times of the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) between subjects with mild-to-moderate knee osteoarthritis (OA) and healthy controls. Methods A single knee of 15 patients with mild-to-moderate knee OA (Kellgren-Lawrence grades 2–3) and of 6 age-matched controls was imaged using a 3.0 T MRI. Three-dimensional (3D) fat-saturated spoiled gradient recalled-echo images were acquired for morphological assessment and T1ρ- and T2-prepared pseudo-steady-state 3D fast spin echo images for compositional assessment of the cruciate ligaments. Manual segmentation of whole ACL and PCL, as well as proximal / middle / distal thirds of both ligaments was carried out by two readers using ITK-SNAP and mean relaxation times were recorded. Variation between thirds of the ligament were assessed using repeated measures ANOVAs and differences in these variations between groups using a Kruskal-Wallis test. Inter- and intra-rater reliability were assessed using intraclass correlation coefficients (ICCs). Results In OA knees, both T1rho and T2 values were significantly higher in the distal ACL when compared to the rest of the ligament with the greatest differences in T1rho (e.g. distal mean = 54.5 ms, proximal = 47.0 ms, p < 0.001). The variation of T2 values within the PCL was lower in OA knees (OA: distal vs middle vs proximal mean = 28.5 ms vs 29.1 ms vs 28.7 ms, p = 0.748; Control: distal vs middle vs proximal mean = 26.4 ms vs 32.7 ms vs 33.3 ms, p = 0.009). ICCs were excellent for the majority of variables. Conclusion T1rho and T2 mapping of the cruciate ligaments is feasible and reliable. Changes within ligaments associated with OA may not be homogeneous. This study is an important step forward in developing a non-invasive, radiological biomarker to assess the ligaments in diseased human populations in-vivo.

scholarly journals Myocardial Tissue Characterization By T2 Mapping in Thalassemia Major

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 27-28
Author(s):  
Alessia Pepe ◽  
Nicola Martini ◽  
Rita Borrello ◽  
Vincenzo Positano ◽  
Laura Pistoia ◽  
...  
Keyword(s):  
Tissue Characterization ◽  
Spin Echo ◽  
T2 Mapping ◽  
Relaxation Times ◽  
Thalassemia Major ◽  
Fast Spin Echo ◽  
Myocardial Inflammation ◽  
Healthy Population ◽  
Myocardial Iron ◽  
Magnetic Resonance Imaging Mri

Introduction.The presence of iron deposits results in a significant reduction in all magnetic resonance imaging (MRI) relaxation times (T1, T2 and T2*). In the clinical setting the T2* technique is the method of choice for cardiac iron quantification and it has revolutionized the management of patients with hemoglopinopathies. Purpose.To compare myocardial T2 against T2* in patients with thalassemia major (TM) for myocardial iron characterization. Methods.133 TM patients (79 females, 38.4±11.3 years) enrolled in the Extension Myocardial Iron Overload in Thalassemia (eMIOT) Network were considered. T2 and T2* images were acquired, respectively, with multi-echo fast-spin-echo and gradient-echo sequences. Global heart T2 and T2* values were obtained by averaging the values in all 16 myocardial segments. The normal T2 range was established as mean±2 standard deviations on data acquired on 80 healthy volunteers (males: 48-56 ms and females: 50-57 ms). The lower limit of normal for global heart T2*, established on the same healthy population, was 32 ms. Results.A significant correlation was detected between global heart T2 and T2* values (R=0.577; P&lt;0.0001) (Figure). Out of the 113 (84.9%) patients with a normal global heart T2* value, none had a decreased global heart T2 value, while 58 (51.3%) had an increased T2 value. Out of the 20 patents with a decreased global heart T2* value, only 10 (50%) had also a reduced T2 value. Conversely, 9 (45.0%) had a normal global heart T2 value and one (4.5) showed an increased T2 value. The 59 patients with increased global heart T2 value were significantly older than the remaining patients (40.8±10.5 vs 36.4±11.6 years; P=0.019) Conclusion.All patients with decreased T2 value had also a decreased T2* value and in half of the patients iron load was undetected by T2, suggesting that T2 mapping does not offer any advantage in terms of sensitivity for MIO assessment. However, more than half of TM patients had an increased T2 value, thus may be caused by the presence of myocardial inflammation and/or edema. So, T2 mapping could reveal subclinical myocardial involvement in TM patients. Figure Disclosures Pistoia: Chiesi Farmaceutici S.p.A.:Other: speakers' honoraria.Meloni:Chiesi Farmaceutici S.p.A.:Other: speakers' honoraria.

Patellar Malalignment Is Associated With Patellofemoral Lesions and Cartilage Relaxation Times After Hamstring Autograft Anterior Cruciate Ligament Reconstruction

2020 ◽  
Vol 48 (9) ◽  
pp. 2242-2251
Author(s):  
Tzu-Chieh Liao ◽  
Alejandro G. Morales Martinez ◽  
Valentina Pedoia ◽  
Benjamin C. Ma ◽  
Xiaojuan Li ◽  
...  
Keyword(s):  
Lateral Displacement ◽  
Spin Echo ◽  
Cruciate Ligament ◽  
Relaxation Times ◽  
Fast Spin Echo ◽  
Healthy Controls ◽  
Resonance Imaging ◽  
Anterior Cruciate ◽  
Fast Spin ◽  
And Cartilage

Background: There is growing evidence suggesting a link between patellofemoral joint (PFJ) osteoarthritis in anterior cruciate ligament (ACL)–reconstructed knees and altered joint alignment. Purpose: To determine whether patellar alignment differs between participants with and without ACL reconstruction (ACLR) and to identify possible associations between patellar alignment and PFJ osteoarthritis features over 3 years. Study Design: Cohort study; Level of evidence, 2. Methods: A total of 37 participants with ACLR (sex, 23 male; mean ± SD age, 28.1 ± 7.4 years) and 20 healthy controls (13 male; 30.4 ± 4.8 years) participated. Patients underwent magnetic resonance imaging: (1) sagittal T2-weighted fat-saturated fast spin echo images to calculate patellar alignment, (2) sagittal 3-dimensional intermediate-weighted fast spin echo Cube sequence for clinical morphological grading (modified Whole-Organ Magnetic Resonance Imaging Score [WORMS]), and (3) sagittal combined T1ρ/T2 mapping sequence for performing voxel-based relaxometry. Patellar alignment of the ACLR knees were assessed at 6 months (baseline). One-way analysis of variance was used to compare patellar alignment among the ACLR (at 6 months), contralateral, and control knees. Within the ACLR group, a logistic regression model was used to identify if patellar alignment measures at baseline were risk factors for worsening of PFJ structural changes over 3 years. Statistical parametric mapping was used to evaluate the longitudinal associations between patellar alignment and cartilage relaxation times at 3 years. Results: When compared with control knees, ACLR knees exhibited a laterally and anteriorly displaced patella ( P = .045 and P = .041), less flexion ( P = .031), and less lateral spin ( P = .012). Furthermore, excessive lateral displacement was a significant predictor of worsening of WORMS ( P = .050). Lateral displacement was positively correlated with increased T1ρ and T2 in the patellar and trochlear cartilage at 3 years. Patellar lateral spin revealed similar negative findings. Conclusion: Participants with ACLR exhibited a laterally and anteriorly displaced patella, less flexion, and less lateral spin when compared with healthy controls. Excessive patellar lateral displacement was the strongest predictor to the development of PFJ osteoarthritis features longitudinally.

scholarly journals Myocardial Mapping in Systemic Sarcoidosis: A Comparison of Two Measurement Approaches

2020 ◽  
Vol 193 (01) ◽  
pp. 68-76
Author(s):  
Darius Dabir ◽  
Julian Luetkens ◽  
Daniel Kuetting ◽  
Jennifer Nadal ◽  
Hans Heinz Schild ◽  
...  
Keyword(s):  
T1 Mapping ◽  
Tissue Characterization ◽  
Cardiac Involvement ◽  
T2 Mapping ◽  
Relaxation Times ◽  
Short Axis Slice ◽  
T2 Relaxation ◽  
Standard Mapping ◽  
Systemic Sarcoidosis ◽  
T1 And T2

Purpose To investigate if T1 and T2 mapping is able to differentiate between diseased and healthy myocardium in patients with systemic sarcoidosis, and to compare the standard mapping measurement (measurement within the whole myocardium of the midventricular short axis slice, SAX) to a more standardized method measuring relaxation times within the midventricular septum (ConSept). Materials and Methods 24 patients with biopsy-proven extracardiac sarcoidosis and 17 healthy control subjects were prospectively enrolled in this study and underwent CMR imaging at 1.5 T including native T1 and T2 mapping. Patients were divided into patients with (LGE+) and without (LGE–) cardiac sarcoidosis. T1 and T2 relaxation times were compared between patients and controls. Furthermore, the SAX and the ConSept approach were compared regarding differentiation between healthy and diseased myocardium. Results T1 and T2 relaxation times were significantly longer in all patients compared with controls using both the SAX and the ConSept approach (p < 0.05). However, LGE+ and LGE– patients showed no significant differences in T1 and T2 relaxation times regardless of the measurement approach used (ConSept/SAX) (p > 0.05). Direct comparison of ConSept and SAX T1 mapping showed high conformity in the discrimination between healthy and diseased myocardium (Kappa = 0.844). Conclusion T1 and T2 mapping may not only enable noninvasive recognition of cardiac involvement in patients with systemic sarcoidosis but may also serve as a marker for early cardiac involvement of the disease allowing for timely treatment. ConSept T1 mapping represents an equivalent method for tissue characterization in this population compared to the SAX approach. Further studies including follow-up examinations are necessary to confirm these preliminary results. Key Points:  Citation Format

scholarly journals Reproducibility of three different cardiac T2-mapping sequences at 1.5T and impact of cofactors on T2-relaxation times

2015 ◽  
Vol 17 (S1) ◽  
Author(s):  
Bettina Baessler ◽  
Frank Schaarschmidt ◽  
Bernhard Schnackenburg ◽  
Christian Stehning ◽  
Agathe D Giolda ◽  
...  
Keyword(s):  
T2 Mapping ◽  
Relaxation Times ◽  
T2 Relaxation

scholarly journals Performance evaluation of a PET insert for preclinical MRI in stand-alone PET and simultaneous PET–MRI modes

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Gaelle Emvalomenos ◽  
Sofie Trajanovska ◽  
Binh T. T. Pham ◽  
Peter Doughty ◽  
Jerome Burnet ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Spin Echo ◽  
Relaxation Times ◽  
Temperature Stability ◽  
Effect Of Temperature ◽  
Fast Spin Echo ◽  
T2 Relaxation ◽  
Absolute Sensitivity ◽  
Field Homogeneity ◽  
T1 And T2

Abstract Background This study aimed to evaluate the performance of a preclinical PET insert in three configurations: as a stand-alone unit outside the MRI bore, inside the bore of a cryogen-free 3T MRI and, finally, while performing simultaneous PET/MRI studies. Methods The PET insert consists of two rings of six detectors, each detector comprising 8 × 12 SiPMs reading out dual offset layers of pixelated LYSO crystals with a 1.4-mm pitch. The inner diameter is 60 mm, transaxial field of view (FoV) 40 mm and axial FoV 98 mm. Evaluation was based on NEMA NU 4-2008 guidelines with appropriate modifications. Spatial resolution and sensitivity were measured inside and outside the MR bore. Image quality, count rate and quantitative performance were measured in all three configurations. The effect of temperature stability on PET sensitivity during fast spin echo sequences was also evaluated. B0 field homogeneity and T1 and T2 relaxation times were measured using a water-filled phantom, with and without simultaneous PET operation. Finally, PET and MRI scans of a mouse injected with 10 MBq [18F]NaF and a mouse injected with 16 MBq [18F]FDG were performed in sequential and simultaneous modes. Results Peak absolute sensitivity was 10.15% with an energy window of 250–750 keV. Absolute sensitivity values outside and inside the MR bore with MR idle agreed to within 0.1%. Outside the MR bore, spatial resolution was 1.21/1.59 mm FWHM (radial/tangential) 5 mm from the centre of the FoV which compared well with 1.19/1.26 mm FWHM inside the MR bore. There were no substantial differences between all three scan configurations in terms of peak NEC rate (175 kcps at 17 MBq), scatter or random fractions. Uniformity and recovery coefficients were also consistent between scanning modes. B0 field homogeneity and T1 and T2 relaxation times were unaltered by the presence of the PET insert. No significant differences were observed between sequential and simultaneous scans of the animals. Conclusions We conclude that the performance of the PET insert and MRI system is not significantly affected by the scanning mode.

T2 Mapping as a New Method for Quantitative Assessment of Cartilage Damage in Rheumatoid Arthritis

2019 ◽  
Vol 47 (6) ◽  
pp. 820-825 ◽  
Author(s):  
Nina Renner ◽  
Arnd Kleyer ◽  
Gerhard Krönke ◽  
David Simon ◽  
Stefan Söllner ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Articular Cartilage ◽  
Disease Activity ◽  
Disease Duration ◽  
T2 Mapping ◽  
Cartilage Damage ◽  
Relaxation Times ◽  
T2 Relaxation ◽  
Hand Joints ◽  
Magnetic Resonance Imaging Mri

Objective.Rheumatoid arthritis (RA) is associated with damage of the articular cartilage and the periarticular bone. While imaging of bone damage has substantially improved in recent years, direct imaging of the articular cartilage of the hand joints in patients with RA is still challenging. The study used T2 mapping of the finger joints to assess cartilage damage in RA.Methods.Magnetic resonance imaging (MRI) at 3 Tesla was done in 30 patients with RA, and T2 relaxation times visualizing alteration in the collagen network and hydration of articular cartilage were mapped in 6 cartilage regions of the metacarpophalangeal (MCP) joints 2 and 3. Values were related to autoantibody status [anticitrullinated protein antibodies (ACPA), rheumatoid factor (RF)], disease duration, and disease activity as well as sex and age of the patients.Results.T2 relaxation times could be reliably measured in the 6 regions of the MCP joints. Significantly higher relaxation times indicating more advanced cartilage alterations were observed in the metacarpal heads of ACPA-positive (p = 0.001–0.010) and RF-positive patients (p = 0.013–0.025) as well as those with longer disease duration (> 3 yrs; p = 0.028–0.043). Current disease activity, sex, and age did not influence T2 relaxation times.Conclusion.These data show that cartilage damage can be localized and quantified in the hand joints of patients with RA by T2 mapping. Further, ACPA and RF positivity as well as disease duration appear to be the crucial factors influencing cartilage damage.

Performance Evaluation of a PET Insert for Preclinical MRI in Standalone PET and Simultaneous PET-MRI Modes

2021 ◽  
Author(s):  
Gaelle Emvalomenos ◽  
Sofie Trajanovska ◽  
Binh T.T. Pham ◽  
Peter Doughty ◽  
Jerome Burnet ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Spin Echo ◽  
Relaxation Times ◽  
Temperature Stability ◽  
Effect Of Temperature ◽  
Fast Spin Echo ◽  
T2 Relaxation ◽  
Absolute Sensitivity ◽  
Field Homogeneity ◽  
T1 And T2

Abstract Background: This study aimed to evaluate the performance of a preclinical PET insert in three configurations: as a standalone unit outside the MRI bore, inside the bore of a cryogen-free 3T MRI and, finally, while performing simultaneous PET/MRI studies.Methods: The PET insert consists of 2 rings of 6 detectors, each detector comprising 8x12 SiPMs reading out dual offset layers of pixelated LYSO crystals with a 1.4mm pitch. The inner diameter is 60mm, transaxial Field of View (FoV) 40mm and axial FoV 98mm. Evaluation was based on NEMA NU 4-2008 guidelines with appropriate modifications. Spatial resolution and sensitivity were measured inside and outside the MR bore. Image quality, count rate and quantitative performance were measured in all three configurations. The effect of temperature stability on PET sensitivity during fast spin echo sequences was also evaluated. B0 field homogeneity, T1 and T2 relaxation times were measured using a water-filled phantom, with and without simultaneous PET operation. Finally, PET and MRI scans of a mouse injected with 10 MBq [18F]NaF and a mouse injected with 16 MBq [18F]FDG were performed in sequential and simultaneous modes. Results: Peak absolute sensitivity was 10.15% with an energy window of 250-750 keV. Absolute sensitivity values outside and inside the MR bore with MR idle agreed to within 0.1%. Outside the MR bore spatial resolution was 1.21/1.59 mm FWHM (radial/tangential) 5mm from the centre of the FoV which compared well with 1.19/1.26mm FWHM inside the MR bore. There were no substantial differences between all three scan configurations in terms of peak NEC rate (175 kcps at 17MBq), scatter or random fractions. Uniformity and recovery coefficients were also consistent between scanning modes. B0 field homogeneity and T1 and T2 relaxation times were unaltered by the presence of the PET insert. No significant differences were observed between sequential and simultaneous scans of the animals.Conclusion: We conclude that performance of the PET insert and MRI system are not significantly affected by scanning mode.

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