MRI evaluation of articular cartilage in patients with juvenile osteochondritis dissecans (JOCD) using T2∗ mapping at 3T.

OBJECTIVE: Evaluate articular cartilage by magnetic resonance imaging (MRI) T2∗ mapping within the distal femur and proximal tibia in adolescents with juvenile osteochondritis dissecans (JOCD). DESIGN: JOCD imaging studies acquired between August 2011 and February 2019 with clinical and T2∗ mapping MRI knee images were retrospectively collected and analyzed for 31 participants (9F/22M, 15.0 ± 3.8 years old) with JOCD lesions in the medial femoral condyle (MFC). In total, N = 32 knees with JOCD lesions and N = 14 control knees were assessed. Mean T2∗ values in four articular cartilage regions-of-interest (MFC, lateral femoral condyle (LFC), medial tibia (MT), and lateral tibia (LT)) and lesion volume were measured and analyzed using Wilcoxon-rank-sum tests and Spearman correlation coefficients (R). RESULTS: Mean ± standard error T2∗ differences observed between the lesion-sided MFC and the LFC in JOCD-affected knees (28.5 ± 0.9 95% confidence interval [26.8, 30.3] vs 26.3 ± 0.7 [24.8, 27.7] ms, P = 0.088) and between the affected- and control-knee MFC (28.5 ± 0.9 [26.8, 30.3] vs 28.5 ± 0.6 [27.1, 29.9] ms, P = 0.719) were nonsignificant. T2∗ was significantly increased in the lesion-sided MT vs the LT for the JOCD-affected knees (21.5 ± 0.7 [20.1, 22.9] vs 18.0 ± 0.7 [16.5, 19.5] ms, P = 0.002), but this same difference was also observed between the MT and LT in control knees (21.0 ± 0.6 [19.7, 22.3] vs 18.1 ± 1.1 [15.8, 20.4] ms, P = 0.037). There was no significant T2∗ difference between the affected- and control-knee MT (21.5 ± 0.7 [20.1, 22.9] vs 21.0 ± 0.6 [19.7, 22.3] ms, P = 0.905). T2∗ within the lesion-sided MFC was not correlated with patient age (R = 0.20, P = 0.28) or lesion volume (R = 0.06, P = 0.75). T2∗ values were slightly increased near lesions in later-stage JOCD subjects but without statistical significance. CONCLUSIONS: T2∗ relaxations times were not significantly different from control sites in the articular cartilage overlying JOCD lesions in the MFC or adjacent MT cartilage in early-stage JOCD.

Morphological and compositional monitoring of a new cell-free cartilage repair hydrogel technology - GelrinC by MR using semi-quantitative MOCART scoring and quantitative T2 index and new zonal T2 index calculation.

OBJECTIVE: To evaluate cartilage repair tissue (RT) using MOCART scoring for morphological and T2 mapping for biochemical assessment following implantation of GelrinC, a biosynthetic, biodegradable hydrogel implant. DESIGN: MR imaging (1.5/3T) was performed on 21 patients at six sites. Standard protocols were used for MOCART evaluation at 1 week (baseline) 1, 3, 6, 12, 18 and 24 months. Multi-echo SE was used for T2 mapping. Global (T2 in RT divided by T2 in normal cartilage) and zonal T2 index (deep T2 divided by superficial T2) of RT were calculated. RESULTS: Average MOCART score was 71.8 (95% CI 62.2 to 81.3) at six, 75.2 (95% CI 62.8 to 87.5) at twelve, 71.8 (95% CI 55.4 to 88.2) at eighteen and 84.4 (95% CI 77.7 to 91.0) at twenty-four months. The global T2 index ranged between 0.8 and 1.2 (normal healthy cartilage) in 1/11 (9%) patients at baseline, 8/12 (67%) at 12 months, 11/13 (85%) at 18 months and 13/16 (81%) at 24 months. The zonal T2 index for RT was <20% difference to the zonal T2 index for normal cartilage in: 6/12 patients (50%) at 12 months, 7/13 (53.8%) at 18 months and 10/16 (63.5%) at 24 months. The standard deviation for T2 showed a significant decrease over the study. CONCLUSIONS: The increase of MOCART scores over follow-up indicates improving cartilage repair tissue. Global and zonal T2 repair values at 24 months reached normal cartilage in 81% and 63.5% of the patients respectively, reflecting collagen organization similar to hyaline cartilage.

Technical Note: evaluation of the uncertainties in (choline + creatine)/citrate ratios measured by proton MR spectroscopic imaging in patients suspicious for prostate cancer.

The presented evaluation of the relative uncertainty (δ'CCC) of the (choline + creatine)/citrate (CC/C) ratios can provide objective information about the quality and diagnostic value of prostate MR spectroscopic imaging data. This information can be combined with the numeric values of CC/C ratios and provides metabolic-quality maps enabling accurate cancer detection and user-independent data evaluation. In addition, the prostate areas suffering most from the low precision of CC/C ratios (e. g., prostate base) were identified.

Evaluation of native hyaline cartilage and repair tissue after two cartilage repair surgery techniques with 23Na MR imaging at 7 T: initial experience.

OBJECTIVE: To compare the sodium normalized mean signal intensity (NMSI) values between patients after bone marrow stimulation (BMS) and matrix-associated autologous chondrocyte transplantation (MACT) cartilage repair procedures. METHODS: Nine BMS and nine MACT patients were included. Each BMS patient was matched with one MACT patient according to age [BMS 36.7 ± 10.7 (mean ± standard deviation) years; MACT 36.9 ± 10.0 years], postoperative interval (BMS 33.5 ± 25.3 months; MACT 33.2 ± 25.7 months), and defect location. All magnetic resonance imaging (MRI) measurements were performed on a 7 T system. Proton images served for morphological evaluation of repair tissue using the magnetic resonance observation of cartilage repair tissue (MOCART) scoring system. Sodium NMSI values in the repair area and morphologically normal cartilage were calculated. Clinical outcome was assessed right after MRI. Analysis of covariance, t-tests, and Pearson correlation coefficients were evaluated. RESULTS: Sodium NMSI was significantly lower in BMS (P = 0.004) and MACT (P = 0.006) repair tissue, compared to reference cartilage. Sodium NMSI was not different between the reference cartilage in MACT and BMS patients (P = 0.664), however it was significantly higher in MACT than in BMS repair tissue (P = 0.028). Better clinical outcome was observed in BMS than in MACT patients. There was no difference between MOCART scores for MACT and BMS patients (P = 0.915). We did not observe any significant correlation between MOCART score and sodium repair tissue NMSI (r = -0.001; P = 0.996). CONCLUSIONS: Our results suggest higher glycosaminoglycan (GAG) content, and therefore, repair tissue of better quality in MACT than in BMS patients. Sodium imaging might be beneficial in non-invasive evaluation of cartilage repair surgery efficacy.

[Diagnose importance of multiparametric magnetic resonance tomography for prostate cancer]. / Stellenwert der multiparametrischen Magnetresonanztomographie beim Prostatakarzinom.

Prostate cancer is biologically and clinically a heterogeneous disease which makes imaging evaluation challenging. Magnetic resonance imaging (MRI) has considerable potential to improve prostate cancer detection and characterization. Until recently morphologic MRI has not been routinely incorporated into clinical care because of its limitation to detect, localize and characterize prostate cancer. Performing prostate gland MRI using functional techniques has the potential to provide unique information regarding tumor behavior, including treatment response. In order for multiparametric MRI data to have an impact on patient management, the collected data need to be relayed to clinicians in a standardized way for image construction, analysis and interpretation. This will ensure that patients are treated effectively and in the most appropriate way. Scoring systems similar to those employed successfully for breast imaging need to be developed.