The MOCART (Magnetic Resonance Observation of Cartilage Repair Tissue) 2.0 Knee Score and Atlas

Objective Since the first introduction of the MOCART (Magnetic Resonance Observation of Cartilage Repair Tissue) score, significant progress has been made with regard to surgical treatment options for cartilage defects, as well as magnetic resonance imaging (MRI) of such defects. Thus, the aim of this study was to introduce the MOCART 2.0 knee score — an incremental update on the original MOCART score — that incorporates this progression. Materials and Methods The volume of cartilage defect filling is now assessed in 25% increments, with hypertrophic filling of up to 150% receiving the same scoring as complete repair. Integration now assesses only the integration to neighboring native cartilage, and the severity of surface irregularities is assessed in reference to cartilage repair length rather than depth. The signal intensity of the repair tissue differentiates normal signal, minor abnormal, or severely abnormal signal alterations. The assessment of the variables "subchondral lamina," "adhesions," and "synovitis" was removed and the points were reallocated to the new variable "bony defect or bony overgrowth." The variable "subchondral bone" was renamed to "subchondral changes" and assesses minor and severe edema-like marrow signal, as well as subchondral cysts or osteonecrosis-like signal. Overall, a MOCART 2.0 knee score ranging from 0 to 100 points may be reached. Four independent readers (two expert readers and two radiology residents with limited experience) assessed the 3 T MRI examinations of 24 patients, who had undergone cartilage repair of a femoral cartilage defect using the new MOCART 2.0 knee score. One of the expert readers and both inexperienced readers performed two readings, separated by a four-week interval. For the inexperienced readers, the first reading was based on the evaluation sheet only. For the second reading, a newly introduced atlas was used as an additional reference. Intrarater and interrater reliability was assessed using intraclass correlation coefficients (ICCs) and weighted kappa statistics. ICCs were interpreted according to Koo and Li; weighted kappa statistics were interpreted according to the criteria of Landis and Koch. Results The overall intrarater (ICC = 0.88, P < 0.001) as well as the interrater (ICC = 0.84, P < 0.001) reliability of the expert readers was almost perfect. Based on the evaluation sheet of the MOCART 2.0 knee score, the overall interrater reliability of the inexperienced readers was poor (ICC = 0.34, P < 0.019) and improved to moderate (ICC = 0.59, P = 0.001) with the use of the atlas. Conclusions The MOCART 2.0 knee score was updated to account for changes in the past decade and demonstrates almost perfect interrater and intrarater reliability in expert readers. In inexperienced readers, use of the atlas may improve interrater reliability and, thus, increase the comparability of results across studies

Clinical applications at ultrahigh field (7 T): where does it make the difference?

Presently, three major MR vendors provide commercial 7-T units for clinical research under ethical permission, with the number of operating 7-T systems having increased to over 50. This rapid increase indicates the growing interest in ultrahigh-field MRI because of improved clinical results with regard to morphological as well as functional and metabolic capabilities. As the signal-to-noise ratio scales linearly with the field strength (B) of the scanner, the most obvious application at 7 T is to obtain higher spatial resolution in the brain, musculoskeletal system and breast. Of specific clinical interest for neuro-applications is the cerebral cortex at 7 T, for the detection of changes in cortical structure as a sign of early dementia, as well as for the visualization of cortical microinfarcts and cortical plaques in multiple sclerosis. In the imaging of the hippocampus, even subfields of the internal hippocampal anatomy and pathology can be visualized with excellent resolution. The dynamic and static blood oxygenation level-dependent contrast increases linearly with the field strength, which significantly improves the pre-surgical evaluation of eloquent areas before tumor removal. Using susceptibility-weighted imaging, the plaque–vessel relationship and iron accumulation in multiple sclerosis can be visualized for the first time. Multi-nuclear clinical applications, such as sodium imaging for the evaluation of repair tissue quality after cartilage transplantation and P spectroscopy for the differentiation between non-alcoholic benign liver disease and potentially progressive steatohepatitis, are only possible at ultrahigh fields. Although neuro- and musculoskeletal imaging have already demonstrated the clinical superiority of ultrahigh fields, whole-body clinical applications at 7 T are still limited, mainly because of the lack of suitable coils. The purpose of this article was therefore to review the clinical studies that have been performed thus far at 7 T, compared with 3 T, as well as those studies performed at 7 T that cannot be routinely performed at 3 T

The Journal of Dentists / Detection of Degenerative Changes in the Articular Disc of the Temporomandibular Joint Using Delayed Gadolinium- Enhanced MRI at 3 Tesla : A Case Report

The delayed Gadolinium-Enhanced Magnetic Resonance Imaging of Cartilage (dGEMRIC) is a useful tool for the evaluation of a repair tissue status after cartilage transplantation. A previous study showed the feasibility of dGEMRIC at 3 Tesla in TMJ. This case report describes the application of dGEMRIC to a TMD patient. A 27 years old female patient reported TMJ (VAS 87) with increasing intensity. The examination according to RDC/TMD showed myofacial pain (group I) and arthralgia of the right and left joint (IIIa). The graded chronical pain score showed grade III. The conventional MRI showed no sign of discus dislocation. T2 mapping showed a significant signal in homogeneity in both disci, as well as an increased amount of fluid in both compartments and a flattened disc in the lateral area. The application of dGEMRIC with patients suffering from temporomandibular disorders could be very well suited for early detection of onset pathological change in fibrocartilage.(VLID)473205

A comparison of multi-echo spin-echo and triple-echo steady-state T2 mapping for in vivo evaluation of articular cartilage

To assess the clinical relevance of T-2 relaxation times, measured by 3D triple-echo steady-state (3D-TESS), in knee articular cartilage compared to conventional multi-echo spin-echo T-2-mapping. Thirteen volunteers and ten patients with focal cartilage lesions were included in this prospective study. All subjects underwent 3-Tesla MRI consisting of a multi-echo multi-slice spin-echo sequence (CPMG) as a reference method for T-2 mapping, and 3D TESS with the same geometry settings, but variable acquisition times: standard (TESSs 4:35min) and quick (TESSq 2:05min). T-2 values were compared in six different regions in the femoral and tibial cartilage using a Wilcoxon signed ranks test and the Pearson correlation coefficient (r). The local ethics committee approved this study, and all participants gave written informed consent. The mean quantitative T-2 values measured by CPMG (mean: 46 +/- 9ms) in volunteers were significantly higher compared to those measured with TESS (mean: 31 +/- 5ms) in all regions. Both methods performed similarly in patients, but CPMG provided a slightly higher difference between lesions and native cartilage (CPMG: 90ms -> 61ms [31%],p=0.0125;TESS 32ms -> 24ms [24%],p=0.0839). 3D-TESS provides results similar to those of a conventional multi-echo spin-echo sequence with many benefits, such as shortening of total acquisition time and insensitivity to B-1 and B-0 changes. aEuro cent 3D-TESS T (2) mapping provides clinically comparable results to CPMG in shorter scan-time. aEuro cent Clinical and investigational studies may benefit from high temporal resolution of 3D-TESS. aEuro cent 3D-TESS T (2) values are able to differentiate between healthy and damaged cartilage.P 25246-B24(VLID)308411

23Na MR imaging at 7 T after knee matrix-associated autologous chondrocyte transplantation preliminary results

To evaluate the feasibility of sodium 7-T magnetic resonance (MR) imaging in repaired tissue and native cartilage of patients after matrix-associated autologous chondrocyte transplantation (MACT) and compare results with delayed gadolinium-enhanced MR imaging of cartilage (dGEMRIC) at 3 T

The comparison of the performance of 3 T and 7 T T mapping for untreated low-grade cartilage lesions.

OBJECTIVE: To investigate T mapping as a possible marker for low-grade human articular cartilage lesions during a one-year follow-up, possible changes during the follow-up and compare the reliability and sensitivity of these measurements on high-field (3 T) and ultra-high-field (7 T) MRI scanners. DESIGN: Twenty-one patients with femoral, tibial and patellar cartilage defect in the knee joint participated in the study. The MRI protocol consisted of morphological, as well as three-dimensional triple-echo steady-state (3D-TESS) T2 mapping sequences with similar parameters at 3T and 7T. Patients were scanned at five time-points up to 12 months. T2 values were evaluated in the lesion and healthy-appearing regions for superficial and deep cartilage zone. The repeated ANOVA was used to determine differences in T2 values at various time points. RESULTS: A significant decrease in T2 values was observed between baseline and six months in the superficial layer of the lesion in patients at 3 T (decrease from 41.89 ± 9.3 ms to 31.21 ± 7.2 ms, which is a difference of -5.67 ± 2.2 ms (p = 0.031)), and at 12 months in the superficial layer of the lesion in patients at 3 T (decrease from 41.89 ± 9.3 ms to 35.28 ± 4.9 ms, which is a difference of -6.60 ± 4.4 ms (p = 0.044). No significant differences were recorded at 7 T. CONCLUSION: The change in T2 values acquired with 3 T 3D-TESS appears to be reflecting subtle changes of cartilage composition in the course of low-grade lesion development. 7 T T2 mapping does not reflect these changes probably due to completely decayed short T2 component

Gadolinium diethylenetriaminepentaacetate enhancement kinetics in the menisci of asymptomatic subjects: a first step towards a dedicated dGEMRIC (delayed gadolinium-enhanced MRI of cartilage)-like protocol for biochemical imaging of the menisci

It was our aim to investigate the gadolinium diethylenetriaminepentaacetate (Gd-DTPA(2-) ) enhancement kinetics in the menisci of the knee joint over a prolonged period of time. Six asymptomatic volunteers (four men and two women; mean age, 25 ± 2.4 years) were enrolled. Sagittal, T(1) -weighted, spin-echo MR sequences of the right knee joint were obtained at 3 T. Imaging was performed before (baseline), 1 h after and in half-hour intervals up to 9 h after the intravenous administration of 0.2 mmol/kg of Gd-DTPA(2-) . To measure the rates of contrast enhancement relative to the baseline, regions of interest that covered the anterior and posterior horns of the medial and lateral meniscus were defined on each of two adjacent sections, and enhancement curves were constructed. An enhancement peak between 2.5 and 4.5 h after Gd-DTPA(2-) administration was observed, and analysis of variance also revealed no significant difference (p=0.94), in terms of enhancement, within this time interval. Pair-wise, post hoc testing also revealed no significant differences between 2.5 and 3, 3 and 3.5, 3.5 and 4, and 4 and 4.5 h post Gd-DTPA(2-) application. Our preliminary data therefore suggest that the time window suitable for a dGEMRIC (delayed gadolinium-enhanced MRI of cartilage)-like T(1) mapping of the menisci is relatively short, and lies between 2.5 and 4.5 h after Gd-DTPA(2-) injection

MR Fingerprinting&mdash;A Radiogenomic Marker for Diffuse Gliomas

(1) Background: Advanced MR imaging (MRI) of brain tumors is mainly based on qualitative contrast images. MR Fingerprinting (MRF) offers a novel approach. The purpose of this study was to use MRF-derived T1 and T2 relaxation maps to differentiate diffuse gliomas according to isocitrate dehydrogenase (IDH) mutation. (2) Methods: Twenty-four patients with histologically verified diffuse gliomas (14 IDH-mutant, four 1p/19q-codeleted, 10 IDH-wildtype) were enrolled. MRF T1 and T2 relaxation times were compared to apparent diffusion coefficient (ADC), relative cerebral blood volume (rCBV) within solid tumor, peritumoral edema, and normal-appearing white matter (NAWM), using contrast-enhanced MRI, diffusion-, perfusion-, and susceptibility-weighted imaging. For perfusion imaging, a T2* weighted perfusion sequence with leakage correction was used. Correlations of MRF T1 and T2 times with two established conventional sequences for T1 and T2 mapping were assessed (a fast double inversion recovery-based MR sequence (&lsquo;MP2RAGE&rsquo;) for T1 quantification and a multi-contrast spin echo-based sequence for T2 quantification). (3) Results: MRF T1 and T2 relaxation times were significantly higher in the IDH-mutant than in IDH-wildtype gliomas within the solid part of the tumor (p = 0.024 for MRF T1, p = 0.041 for MRF T2). MRF T1 and T2 relaxation times were significantly higher in the IDH-wildtype than in IDH-mutant gliomas within peritumoral edema less than or equal to 1cm adjacent to the tumor (p = 0.038 for MRF T1 mean, p = 0.010 for MRF T2 mean). In the solid part of the tumor, there was a high correlation between MRF and conventionally measured T1 and T2 values (r = 0.913, p &lt; 0.001 for T1, r = 0.775, p &lt; 0.001 for T2), as well as between MRF and ADC values (r = 0.813, p &lt; 0.001 for T2, r = 0.697, p &lt; 0.001 for T1). The correlation was weak between the MRF and rCBV values (r = &minus;0.374, p = 0.005 for T2, r = &minus;0.181, p = 0.181 for T1). (4) Conclusions: MRF enables fast, single-sequence based, multi-parametric, quantitative tissue characterization of diffuse gliomas and may have the potential to differentiate IDH-mutant from IDH-wildtype gliomas

Sodium MR imaging of the lumbar intervertebral disk at 7 T: correlation with T2 mapping and modified Pfirrmann score at 3 T - preliminary results

PURPOSE: To compare sodium imaging of lumbar intervertebral disks in asymptomatic volunteers at 7-T magnetic resonance (MR) imaging with quantitative T2 mapping and morphologic scoring at 3 T. MATERIALS AND METHODS: Following ethical board approval and informed consent, the L2-3 to L5-S1 disks were examined in 10 asymptomatic volunteers (nine men, one woman; mean age, 30 years; range, 23-43 years). At 7 T, normalized sodium signal-to-noise ratios were calculated, by using region-of-interest analysis. At 3 T, T2 mapping was performed with a multiecho spin-echo sequence (repetition time msec/echo times msec, 1500/24, 36, 48, 60, 72, 84, 96, 108, 120, 132, 144, 156). T2 values were calculated over the nucleus, with a pixelwise, monoexponential nonnegative least-squares-fit analysis. Morphologic grading according to a modified Pfirrmann score was assessed independently by three experienced musculoskeletal radiologists, and Pearson correlation analysis of the covariates was performed. RESULTS: The mean normalized sodium signal intensity was 275.5±115.4 (standard deviation). The T2 mapping showed a mean value of 89.8 msec±19.34. The median modified Pfirrmann score was 2b (90% had score≤3c). The Pearson correlation coefficient showed a cubic function between sodium imaging and the modified Pfirrmann score, a moderate inverse correlation between T2 mapping and the modified Pfirrmann score (r=-0.62), and no correlation between sodium imaging and T2 mapping (r=0.06). CONCLUSION: The results suggest that MR imaging of the intervertebral disk, using sodium imaging and T2 mapping, can help characterize different component changes and that both of these methods are to some degree related to the Pfirrmann score