Publications by authors named "Pavol Szomolanyi"

57 Publications

Soft Tissue Sarcoma Follow-up Imaging: Strategies to Distinguish Post-treatment Changes from Recurrence.

Semin Musculoskelet Radiol 2020 Dec 11;24(6):627-644. Epub 2020 Dec 11.

Department of radiology, Leiden University Medical Center, Leiden, The Netherlands.

Soft tissue sarcomas encompass multiple entities with differing recurrence rates and follow-up intervals. The detection of recurrences and their differentiation from post-therapeutic changes is therefore complex, with a central role for the clinical radiologist. This article describes approved recommendations. Prerequisite is a precise knowledge of the current clinical management and surgical techniques. We review recurrence rates and treatment modalities. An adequate imaging technique is paramount, and comparison with previous imaging is highly recommended. We describe time-dependent therapy-related complications on magnetic resonance imaging compared with the spectrum of regular post-therapeutic changes. Early complications such as seromas, hematomas, and infections, late complications such as edema and fibrosis, and inflammatory pseudotumors are elucidated. The appearance of recurrences and radiation-associated sarcomas is contrasted with these changes. This systematic approach in follow-up imaging of soft tissue sarcoma patients will facilitate the differentiation of post-therapeutic changes from recurrences.
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http://dx.doi.org/10.1055/s-0040-1721464DOI Listing
December 2020

Reproducibility of an Automated Quantitative MRI Assessment of Low-Grade Knee Articular Cartilage Lesions.

Cartilage 2020 Sep 29:1947603520961165. Epub 2020 Sep 29.

High-Field MR Centre, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria.

Objective: The goal of this study was to assess the reproducibility of an automated knee cartilage segmentation of 21 cartilage regions with a model-based algorithm and to compare the results with manual segmentation.

Design: Thirteen patients with low-grade femoral cartilage defects were included in the study and were scanned twice on a 7-T magnetic resonance imaging (MRI) scanner 8 days apart. A 3-dimensional double-echo steady-state (3D-DESS) sequence was used to acquire MR images for automated cartilage segmentation, and T2-mapping was performed using a 3D triple-echo steady-state (3D-TESS) sequence. Cartilage volume, thickness, and T2 and texture features were automatically extracted from each knee for each of the 21 subregions. DESS was used for manual cartilage segmentation and compared with automated segmentation using the Dice coefficient. The reproducibility of each variable was expressed using standard error of measurement (SEM) and smallest detectable change (SDC).

Results: The Dice coefficient for the similarity between manual and automated segmentation ranged from 0.83 to 0.88 in different cartilage regions. Test-retest analysis of automated cartilage segmentation and automated quantitative parameter extraction revealed excellent reproducibility for volume measurement (mean SDC for all subregions of 85.6 mm), for thickness detection (SDC = 0.16 mm) and also for T2 values (SDC = 2.38 ms) and most gray-level co-occurrence matrix features (SDC = 0.1 a.u.).

Conclusions: The proposed technique of automated knee cartilage evaluation based on the segmentation of 3D MR images and correlation with T2 mapping provides highly reproducible results and significantly reduces the segmentation effort required for the analysis of knee articular cartilage in longitudinal studies.
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http://dx.doi.org/10.1177/1947603520961165DOI Listing
September 2020

Frontiers of Sodium MRI Revisited: From Cartilage to Brain Imaging.

J Magn Reson Imaging 2020 Aug 26:e27326. Epub 2020 Aug 26.

Institute for Clinical Molecular MRI in the Musculoskeletal System, Karl Landsteiner Society, Vienna, Austria.

Sodium magnetic resonance imaging ( Na-MRI) is a highly promising imaging modality that offers the possibility to noninvasively quantify sodium content in the tissue, one of the most relevant parameters for biochemical investigations. Despite its great potential, due to the intrinsically low signal-to-noise ratio (SNR) of sodium imaging generated by low in vivo sodium concentrations, low gyromagnetic ratio, and substantially shorter relaxation times than for proton ( H) imaging, Na-MRI is extremely challenging. In this article, we aim to provide a comprehensive overview of the literature that has been published in the last 10-15 years and which has demonstrated different technical designs for a range of Na-MRI methods applicable for disease diagnoses and treatment efficacy evaluations. Currently, a wider use of 3.0T and 7.0T systems provide imaging with the expected increase in SNR and, consequently, an increased image resolution and a reduced scanning time. A great interest in translational research has enlarged the field of sodium MRI applications to almost all parts of the body: articular cartilage tendons, spine, heart, breast, muscle, kidney, and brain, etc., and several pathological conditions, such as tumors, neurological and degenerative diseases, and others. The quantitative parameter, tissue sodium concentration, which reflects changes in intracellular sodium concentration, extracellular sodium concentration, and intra-/extracellular volume fractions is becoming acknowledged as a reliable biomarker. Although the great potential of this technique is evident, there must be steady technical development for Na-MRI to become a standard imaging tool. The future role of sodium imaging is not to be considered as an alternative to H MRI, but to provide early, diagnostically valuable information about altered metabolism or tissue function associated with disease genesis and progression. LEVEL OF EVIDENCE: 1 TECHNICAL EFFICACY STAGE: 1.
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http://dx.doi.org/10.1002/jmri.27326DOI Listing
August 2020

Chondral and Osteochondral Femoral Cartilage Lesions Treated with GelrinC: Significant Improvement of Radiological Outcome Over Time and Zonal Variation of the Repair Tissue Based on T Mapping at 24 Months.

Cartilage 2020 Jun 4:1947603520926702. Epub 2020 Jun 4.

High Field MR Center, Department of Biomedical Imaging and Image-Guided Therapy, CD Laboratory for Clinical Molecular MR Imaging, Medical University of Vienna, Vienna, Austria.

Objective: To prospectively assess the efficacy of GelrinC in the treatment of chondral and osteochondral femoral cartilage lesions using morphological (Magnetic Resonance Observation of Cartilage Repair Tissue [MOCART]) and quantitative (T-mapping) magnetic resonance imaging (MRI).

Design: This study was designed as a prospective single-arm, open label, multicenter study. Morphological magnetic resonance imaging (MRI) for MOCART assessment and T mapping was performed 1 week and 6, 12, 18, and 24 months after GelrinC implantation. Evaluation of T mapping was based on the assessment of global T indices (T of the repair tissue [RT] divided by T of healthy reference cartilage) and zonal variation.

Results: Fifty-six (20 female) patients were prospectively enrolled. The mean MOCART score significantly increased from baseline to the 24-month follow-up with 88.8 (95% CI, 85.8-91.9; < 0.001) for all lesions combined as well as 86.8 (95% CI, 83.0-90.6) for chondral lesions and 94.1 (95% CI, 68.55-100) for osteochondral lesions. Furthermore, based on T mapping, significant zonal variation of the RT was observed at 24 months ( = 0.039), which did not differ significantly from healthy reference cartilage ( = 0.6).

Conclusion: Increasing MOCART scores were observed throughout the follow-up period, indicative of maturation of the cartilage repair. Significant zonal variation of the RT at 24 months might indicate the transformation into hyaline cartilage-like RT. Slightly differing morphological outcome between chondral and osteochondral lesions, but similar global and zonal T indices at 24 months, support the potential of GelrinC as a treatment option for both lesion types.
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http://dx.doi.org/10.1177/1947603520926702DOI Listing
June 2020

Radiofrequency Chondroplasty May Not Have A Long-Lasting Effect in the Treatment of Concomitant Grade II Patellar Cartilage Defects in Humans.

J Clin Med 2020 Apr 22;9(4). Epub 2020 Apr 22.

Department of Orthopedics and Trauma Surgery, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria.

The effect of radiofrequency chondroplasty on cartilage tissue is not well studied. This prospective pilot study investigates the effect of radiofrequency chondroplasty on International Cartilage Repair Society (ICRS) grade II patellar cartilage defects using high-resolution magnetic resonance imaging (MRI) with T2 mapping. Six consecutive patients were treated for ICRS grade II patellar cartilage defects using radiofrequency chondroplasty. Before surgery and at defined follow-ups (2 weeks, 4 and 12 months) a high-resolution morphological 3 Tesla MRI with quantitative T2 mapping was performed. At baseline MRI, global T2 values of cartilage defects were increased (46.8 ms ± 9.7) compared to healthy cartilage (35.2 ms ± 4.5) in the same knee which served as reference. Two weeks after treatment, global T2 values (39.2 ms ± 7.7) of the defect areas decreased. However, global T2 values of the defect areas increased beyond the preoperative levels at 4 months (47.4 ms ± 3.1) and 12 months (51.5 ms ± 5.9), respectively. Zonal T2 mapping revealed that the predominant changes in T2 values occurred at the superficial cartilage layer. T2 mapping appears to be an ideal method to monitor cartilage degeneration after chondroplasty. Based on the small sample size of this pilot study, radiofrequency chondroplasty may cause cartilage damage and may not have a long-lasting effect in the treatment of grade II patellar cartilage defects. In five out of six patients, postoperative cartilage damage was observed on quantitative MRI. This study was therefore terminated before completion. We recommend only addressing the pathology which indicated arthroscopy and leaving concomitant cartilage lesions untreated.
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http://dx.doi.org/10.3390/jcm9041202DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7230966PMC
April 2020

Impact of concentration and dilution of three macrocyclic gadolinium-based contrast agents on MRI signal intensity at 1.5T and 3T and different pulse sequences: results of a phantom study in human plasma.

Acta Radiol 2021 Jan 14;62(1):51-57. Epub 2020 Apr 14.

Bayer AG, Berlin, Germany.

Background: Many factors influence the increase in signal intensity (SI) provided by magnetic resonance imaging (MRI) contrast media.

Purpose: To assess the impact of different gadolinium concentrations and dilutions of three macrocyclic gadolinium-based contrast agents (GBCA) on SI.

Material And Methods: This phantom study investigated gadobutrol, gadoteridol, and gadoterate in human plasma of a healthy donor pool at 37 °C. Different molar concentrations served to mimic conditions typically relevant for steady-state imaging; different dilutions served to mimic influence on first-pass bolus imaging. For SI measurement at 1.5T and 3T, we used two Magnetom Scanners (Siemens), applying the T1-weighted sequences Flash 2D/3D and VIBE. Regions of interest were placed on the central slice of the test vials.

Results: In the concentration series, gadobutrol showed the highest SI of all three GBCAs up to 2 mM, followed by gadoteridol and gadoterate. No major differences were seen between 1.5T and 3T. In the dilution series, gadobutrol showed the highest SI of all three GBCAs up to 10 mL/L. The highest effect was recorded with Flash 3D and VIBE at 3T.

Conclusion: SIs measured in phantoms using three macrocyclic GBCAs strongly depend on their relaxivity and on the local concentration. The latter can be influenced-when comparing dilutions-by their initial concentration in their formulation. Furthermore, the pulse sequences and the chosen parameters have essential influence. At steady-state concentrations (≤2 mM) and first-pass bolus dilutions (up to 10 ml/L), gadobutrol showed highest SIs, followed by gadoterate and gadoteridol.
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http://dx.doi.org/10.1177/0284185120915674DOI Listing
January 2021

Assessment of Low-Grade Focal Cartilage Lesions in the Knee With Sodium MRI at 7 T: Reproducibility and Short-Term, 6-Month Follow-up Data.

Invest Radiol 2020 07;55(7):430-437

Department of Translational Medicine, Novartis Institutes for Biomedical Research.

Objectives: Several articles have investigated potential of sodium (Na) magnetic resonance imaging (MRI) for the in vivo evaluation of cartilage health, but so far no study tested its feasibility for the evaluation of focal cartilage lesions of grade 1 or 2 as defined by the International Cartilage Repair Society. The aims of this study were to evaluate the ability of Na-MRI to differentiate between early focal lesions and normal-appearing cartilage, to evaluate within-subject reproducibility of Na-MRI, and to monitor longitudinal changes in participants with low-grade, focal chondral lesions.

Materials And Methods: Thirteen participants (mean age, 50.1 ± 10.9 years; 7 women, 6 men) with low-grade, focal cartilage lesions in the weight-bearing region of femoral cartilage were included in this prospective cohort study. Participants were assessed at baseline, 1 week, 3 months, and 6 months using morphological MRI at 3 T and 7 T, compositional Na-MRI at 7 T, and the Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaire. Na signal intensities corrected for coil sensitivity and partial volume effect (Na-cSI) were calculated in the lesion, and in weight-bearing and non-weight-bearing regions of healthy femoral cartilage. Coefficients of variation, repeated measures analysis of covariance models, and Pearson correlation coefficients were calculated to evaluate within-subject reproducibility as well as cross-sectional and longitudinal changes in Na-cSI values.

Results: The mean coefficients of variation of Na-cSI values between the baseline and 1-week follow-up were 5.1% or less in all cartilage regions. Significantly lower Na-cSI values were observed in lesion than in weight-bearing and non-weight-bearing regions at all time points (all P values ≤ 0.002). Although a significant decrease from baseline Na-cSI values in lesion was found at 3-month visit (P = 0.015), no substantial change was observed at 6 months. KOOS scores have improved in all subscales at 3 months and 6 months visit, with a significant increase observed only in the quality of life subscale (P = 0.004).

Conclusions: In vivo Na-MRI is a robust and reproducible method that allows to differentiate between low-grade, focal cartilage lesions and normal-appearing articular cartilage, which supports the concept that compositional cartilage changes can be found early, before the development of advanced morphological changes visible at clinical 3-T MRI.
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http://dx.doi.org/10.1097/RLI.0000000000000652DOI Listing
July 2020

Early diagnosis of degenerative changes in the articular/fibrocartilaginous disc of the temporomandibular joint in patients with temporomandibular disorders using delayed gadolinium-enhanced MRI at 3 Tesla - preliminary results.

Magn Reson Imaging 2020 04 13;67:24-27. Epub 2019 Dec 13.

High-Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria; CD Laboratory for Molecular Clinical MR Imaging, Vienna, Austria; Austrian Cluster for Tissue Regeneration, Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, Vienna, Austria.

Background: Delayed gadolinium enhanced MRI of cartilage (dGEMRIC) is a quantitative method for assessment of glycosaminoglycan content in connective tissues. We hypothesize that the early diagnosis of degenerative changes in the temporomandibular joint could be diagnosed using dGEMRIC technique.

Purpose: To test the compositional MRI technique, dGEMRIC, at 3 Tesla to diagnosis early the degenerative changes in the fibrocartilaginous disc of the temporomandibular joint (TMJ) in patients with temporomandibular disorders (TMD) and to compare the dGEMRIC index of patients to the healthy volunteers.

Methods: Six volunteers (two men, four women; 20.8÷28.1 years) and eleven patients (22 TMJs, seven women, four men; 24÷54 years) were recruited for this prospective trial. Only patients with no morphological abnormality on MRI and without disc dislocations were included. Volunteers were used as a control group. The PD-weighted FSE sequence and the 3D GRE (DESS) sequence protocols were performed for morphological assessment. The Inversion recovery (IR) sequence was performed for T1 relaxation time measurements and intra-venous (IV) contrast agent administration was used according to the dGEMRIC protocol. T1 maps were calculated offline and ROIs were drawn on TMJ discs by a specialist trained in TMD disorders. Statistical evaluation was performed by ANOVA and correlations were calculated.

Results: The difference between the dGEMRIC values in the TMJ articular discs of the patients and the volunteers was statistically significant (P = .019). After contrast agent administration the T1 values dropped in both groups. In patient group was the T1 drop stronger (-54% from initial pre-contrast value), while in control group was the T1 drop less pronounced (-46% from initial pre-contrast value).

Conclusions: dGEMRIC seems to be a useful, compositional, quantitative method, suitable also for small joints, such as the articular disc of the TMJ. The results of the dGEMRIC index in the articular disc of the TMJ imply a lower GAG content in patients with TMJ disorders.
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http://dx.doi.org/10.1016/j.mri.2019.12.002DOI Listing
April 2020

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

Cartilage 2019 Aug 17:1947603519865308. Epub 2019 Aug 17.

2 Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria.

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, < 0.001) as well as the interrater (ICC = 0.84, < 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, < 0.019) and improved to moderate (ICC = 0.59, = 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.
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http://dx.doi.org/10.1177/1947603519865308DOI Listing
August 2019

Comparison of the Relaxivities of Macrocyclic Gadolinium-Based Contrast Agents in Human Plasma at 1.5, 3, and 7 T, and Blood at 3 T.

Invest Radiol 2019 09;54(9):559-564

Bayer AG, Berlin, Germany.

Purpose: The relaxivities of 3 macrocyclic gadolinium-based contrast agents (GBCAs) were determined in human plasma and blood under standardized and clinically relevant laboratory conditions.

Methods: The T1 relaxivity, r1, was determined in human plasma at 1.5, 3, and 7 T, and in human blood at 3 T at 37°C in phantoms containing 4 different concentrations of the macrocyclic GBCAs gadobutrol, gadoteridol, and gadoterate. An inversion recovery turbo spin echo sequence was used to generate images with several inversion times. The T1-times were obtained by fitting the signal intensities to the signal equation. r1 was obtained by a 1/y-weighted regression of the T1-rates over the concentration of the GBCAs.

Results: For gadobutrol, the obtained r1 [L/(mmol·s)] in human plasma at 1.5 T, 3 T, and 7 T, and in human blood at 3 T was 4.78 ± 0.12, 4.97 ± 0.59, 3.83 ± 0.24, and 3.47 ± 0.16. For gadoteridol, r1 was 3.80 ± 0.10, 3.28 ± 0.09, 3.21 ± 0.07, and 2.61 ± 0.16, and for gadoterate, 3.32 ± 0.13, 3.00 ± 0.13, 2.84 ± 0.09, and 2.72 ± 0.17.

Conclusions: The relaxivity of gadobutrol is significantly higher than that of gadoteridol and gadoterate at all magnetic field strengths and in plasma as well as in blood, whereas that of gadoteridol was higher than gadoterate only in plasma at 1.5 and 7 T. This is in accordance with results from 3 previous studies obtained in different media.
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http://dx.doi.org/10.1097/RLI.0000000000000577DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6738537PMC
September 2019

Magnetic Resonance Imaging of the Musculoskeletal System at 7T: Morphological Imaging and Beyond.

Top Magn Reson Imaging 2019 Jun;28(3):125-135

High-field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria.

In 2017, a whole-body 7T magnetic resonance imaging (MRI) device was given regulatory approval for clinical use in both the EU and United States for neuro and musculoskeletal applications. As 7 Tesla allows for higher signal-to-noise , which results in higher resolution images than those obtained on lower-field-strength scanners, it has attracted considerable attention from the musculoskeletal field, as evidenced by the increasing number of publications in the last decade. Besides morphological imaging, the quantitative MR methods, such as T2, T2*, T1ρ mapping, sodium imaging, chemical-exchange saturation transfer, and spectroscopy, substantially benefit from ultrahigh field scanning. In this review, we provide technical considerations for the individual techniques and an overview of (mostly) clinical applications for the assessment of cartilage, tendon, meniscus, and muscle. The first part of the review is dedicated to morphological applications at 7T, and the second part describes the most recent developments in quantitative MRI at 7T.
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http://dx.doi.org/10.1097/RMR.0000000000000205DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6565434PMC
June 2019

T2 mapping with 3.0 T MRI of the temporomandibular joint disc of patients with disc dislocation.

Magn Reson Imaging 2019 05 10;58:125-134. Epub 2019 Feb 10.

High-Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Lazarettgasse 14, 1090 Vienna, Austria; CD Laboratory for Clinical Molecular MR Imaging, Vienna, Austria; Austrian Cluster for Tissue Regeneration, Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, Vienna, Austria. Electronic address:

Introduction: T2 mapping, as a quantitative biochemical MRI-technique that provides information on water and collagen fiber content and composition, was shown to be clinically feasible for the evaluation of healthy temporomandibular joints.

Objectives: The aim of our study was to compare the T2 values of whole discs in patients with and without disc dislocation, to evaluate the possible influence of morphological findings on T2 values and to assess the interrater agreement.

Methods: Sixty-six patients were included in the study. Three experienced examiners assessed the perceptibility of the morphological parameters and the position of the articular disc on the morphological MR images. On the T2 maps, the T2 values of the region-of-interest (ROI) were assessed.

Results: The ICC (Intraclass Correlation Coefficient) for the reproducibility of the T2 values was 0.717. The assessment of the morphologic parameters was excellent or good in most of the discs. There was no significant difference in the T2 values based on disc position or signal intensity. But, a statistically significant moderation effect (p = .014) could be identified, indicating that the effect of disc position differs for different signal intensities. Condyle position, effusion, and degenerative changes showed pronounced moderation effects on the T2 values.

Conclusion: Due to the high sensitivity to effusion, T2 mapping currently seems to be unsuitable as a diagnostic tool for routine use in the temporomandibular joint. The moderation effect clearly shows the influence of factors such as signal intensity, effusion, arthrosis, and condyle position. Perhaps a solution for these problems could be the development of dedicated TMJ coils for higher field strengths at 7.0 T.
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http://dx.doi.org/10.1016/j.mri.2019.02.002DOI Listing
May 2019

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

Magn Reson Imaging 2019 01 19;55:86-92. Epub 2018 Sep 19.

High-Field MR Centre, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria; Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria; Austrian Cluster for Tissue Regeneration, Austria. Electronic address:

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) T mapping sequences with similar parameters at 3T and 7T. Patients were scanned at five time-points up to 12 months. T 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 T values at various time points.

Results: A significant decrease in T 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 T 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 T mapping does not reflect these changes probably due to completely decayed short T component.
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http://dx.doi.org/10.1016/j.mri.2018.09.021DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6420148PMC
January 2019

Hamstring tendon autografts do not show complete graft maturity 6 months postoperatively after anterior cruciate ligament reconstruction.

Knee Surg Sports Traumatol Arthrosc 2019 Jan 14;27(1):130-136. Epub 2018 Jul 14.

IRCCS Galeazzi Orthopaedic Institute, Milan, Italy.

Purpose: In this prospective, double-center cohort study, we aim to assess how the anterior cruciate ligament (ACL) signal intensity on magnetic resonance imaging (MRI) potentially varies between a group of patients with anatomic ACL reconstruction using autogenous hamstring grafts 6 months postoperatively and a healthy ACL control group, and how MRI-based graft signal intensity is related to knee laxity.

Methods: Sixty-two consecutive patients who underwent ACL reconstruction using quadrupled hamstring tendon autograft were prospectively invited to participate in this study, and they were evaluated with MRI after 6 months of follow-up. 50 patients with an MRI of their healthy ACL (Clinica Luganese, Lugano, Switzerland) and 12 patients of their contralateral healthy knee (Department of Orthopaedic and Trauma Surgery, Medical University of Vienna, Austria) served as the control group. To evaluate graft maturity, the signal-to-noise quotient (SNQ) was measured in three regions of interest (ROIs) of the proximal, mid-substance and distal ACL graft and the healthy ACL. KT-1000 findings were obtained 6 months postoperatively in the ACL reconstruction group. Statistical analysis was independently performed to outline the differences in the two groups regarding ACL intensity and the correlation between SNQ and KT-1000 values.

Results: There was a significant difference in the mean SNQ between the reconstructed ACL grafts and the healthy ACLs in the proximal and mid-substance regions (p = 0.001 and p = 0.004). The distal region of the reconstructed ACL showed a mean SNQ similar to the native ACL (n.s). Patients with a KT-1000 between 0 and 1 mm showed a mean SNQ of 0.1; however, a poor correlation was found between the mean SNQ and KT-1000 findings, probably due to the small sample size of patients with higher laxity.

Conclusion: After 6 months of follow-up, hamstring tendon autografts for anatomic ACL reconstruction do not show equal MRI signal intensity compared to a healthy ACL and should therefore be considered immature or at least not completely healed even if clinical laxity measurement provides good results. However, in the case of a competitive athlete, who is clinically stable and wants to return to sports at 6 months, performing an MRI to confirm the stage of graft healing might be an option.

Level Of Evidence: Prospective, comparative study II.
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http://dx.doi.org/10.1007/s00167-018-5033-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6510818PMC
January 2019

New Technology in Imaging Cartilage of the Ankle.

Cartilage 2017 Jan 3;8(1):31-41. Epub 2016 Mar 3.

High Field MR Centre, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria.

The incidence of osteochondral lesions, as well as osteoarthritis of the ankle joint following osteochondritis dissecans and trauma, has been reappraised in recent years. Consequently, an increasing number of surgical interventions using different cartilage repair techniques is performed in the ankle joint, which has resulted in a growing demand for repetitive and objective assessment of cartilage tissue and its repair. While morphological imaging does enable monitoring of macroscopic changes with increasing precision, it fails to provide information about the ultrastructural composition of cartilage. The significance of molecular changes in cartilage matrix composition, however, is increasingly recognized, as it is assumed that macroscopic cartilage degeneration is preceded by a loss in glycosaminoglycans and a disorganization of the collagen network. Recent advances in biochemical magnetic resonance imaging (MRI) have yielded sequences sensitive to these changes, thus providing invaluable insight into both early cartilage degeneration and maturation of repair tissue, on a molecular level. The aim of this review was to provide a comprehensive overview of these techniques, including water and collagen-sensitive T2/T2* mapping, as well as glycosaminoglycan-sensitive sequences such as delayed gadolinium-enhanced MRI of cartilage dGEMRIC, and sodium imaging, and describe their applications for the ankle joint.
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http://dx.doi.org/10.1177/1947603516632848DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5154418PMC
January 2017

Spatial variation of fixed charge density in knee joint cartilage from sodium MRI - Implication on knee joint mechanics under static loading.

J Biomech 2016 10 15;49(14):3387-3396. Epub 2016 Sep 15.

Department of Applied Physics, University of Eastern Finland, Kuopio, Finland; Diagnostic Imaging Center, Kuopio University Hospital, Kuopio, Finland.

The effects of fixed charge density (FCD) and cartilage swelling have not been demonstrated on cartilage mechanics on knee joint level before. In this study, we present how the spatial and local variations of FCD affects the mechanical response of the knee joint cartilage during standing (half of the body weight, 13 minutes) using finite element (FE) modeling. The FCD distribution of tibial cartilage of an asymptomatic subject was determined using sodium (Na) MRI at 7T and implemented into a 3-D FE-model of the knee joint (Subject-specific model, FCD: 0.18±0.08 mEq/ml). Tissue deformation in the Subject-specific model was validated against experimental, in vivo loading of the joint conducted with a MR-compatible compression device. For comparison, models with homogeneous FCD distribution (homogeneous model) and FCD distribution obtained from literature (literature model) were created. Immediately after application of the load (dynamic response), the variations in FCD had minor effects on cartilage stresses and strains. After 13 minutes of standing, the spatial and local variations in FCD had most influence on axial strains. In the superficial tibial cartilage in the Subject-specific model, axial strains were increased up to +13% due to smaller FCD (mean -11%), as compared to the homogeneous model. Compared to the literature model, those were decreased up to -18% due to greater FCD (mean +7%). The findings demonstrate that the spatial and local FCD variations in cartilage modulates strains in knee joint cartilage. Thereby, the results highlight the mechanical importance of site-specific content of proteoglycans in cartilage.
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http://dx.doi.org/10.1016/j.jbiomech.2016.09.011DOI Listing
October 2016

Comparison of Routine Knee Magnetic Resonance Imaging at 3 T and 7 T.

Invest Radiol 2017 Jan;52(1):42-54

From the *High Field MR Center, Department of Biomedical Imaging and Image-Guided Therapy, and †Department of Orthopaedics, Medical University of Vienna, Vienna, Austria; ‡Siemens Healthcare Pty Ltd Australia, Imaging & Therapy Systems, Magnetic Resonance, Macquarie Park, New South Wales, Australia; §Siemens Healthcare, Erlangen, Germany; and ∥CD Laboratory for Molecular Clinical MR Imaging, Vienna, Austria.

Objective: The aim of this study was to compare quantitative and semiquantitative parameters (signal-to-noise ratio [SNR] and diagnostic confidence) from a standard knee magnetic resonance imaging (MRI) examination with comparable sequence protocols and acquisition times at 3 T and at 7 T.

Materials And Methods: Forty patients experiencing knee pain of unknown etiology underwent comparable MR protocols with standard turbo-spin echo and short tau inversion recovery sequences of the knee joint (5 sequences) at 3 T and 7 T. For quantitative analysis, SNR was determined using these 5 sequences and 3 additional morphological sequences. For a semiquantitative assessment of diagnostic confidence, a diagnostic confidence score (DCS) was assigned, using a 10-point scale. Two experienced radiologists who specialized in musculoskeletal imaging and who were blinded to the field-strength independently assessed 22 potential pathological findings, in total, in 4 anatomically defined areas in the knee joint and rated their diagnostic confidence.

Results: In quantitative analysis, all sequences provided higher voxel-volume-adjusted SNR values at 7 T compared with that at 3 T. In semiquantitative analysis, summed DCS values for potential pathological findings in each of the 4 anatomically defined areas were higher at 7 T compared with that at 3 T. There was a statistically significant improvement in the DCS for both readers at 7 T for the diagnosis and exclusion of focal or diffuse grade I or II cartilage defects in the patellar cartilage. For 8 potential pathological findings, a statistically significant difference between the 2 field-strengths could be observed for 1 reader only. For the residual 13 potential pathological findings, there was no statistically significant difference observed. The percentage of concordant ratings was 84.6% at 3 T and 85.4% at 7 T.

Conclusions: Ultra-high-field MRI at 7 T improved the overall diagnostic confidence in routine MRI of the knee joint compared with that at 3 T. This is especially true for small joint structures and subtle lesions. Higher spatial resolution was identified as the main reason for this improvement.
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http://dx.doi.org/10.1097/RLI.0000000000000303DOI Listing
January 2017

The compositional difference between ankle and knee cartilage demonstrated by T2 mapping at 7 Tesla MR.

Eur J Radiol 2016 Apr 3;85(4):771-7. Epub 2016 Feb 3.

High Field MR Centre, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria; Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria; Austrian Cluster for Tissue Regeneration, Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, Vienna, Austria.

Objectives: The aim was to systematically compare T2 relaxation times of the knee and ankle cartilage within subjects at 7T.

Methods: Ten healthy volunteers were examined by 7 Tesla MR using a three-dimensional triple-echo steady state sequence (3D-TESS). The differences between seven cartilage compartments (patella, femur, proximal tibia, and distal tibia and talus in both medial and lateral facet) were analyzed by ANOVA.

Results: The results showed statistically significantly higher T2 (mean ± standard deviation, in milliseconds) values in patellar (25.8 ± 1.2) and femoral (24.9 ± 1.3) cartilage compared to the tibial (19.2 ± 1) and talar (18.1 ± 0.6 ms) cartilage. The cartilages of the medial and lateral facet in the ankle joint were not significantly different (p>0.05).

Conclusions: This is the first study to systematically compare within-subject T2 values in the knee and ankle non-invasively, in vivo. Our results are in agreement with the previous findings demonstrating different biochemical and biomechanical properties between the knee and ankle cartilage.
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http://dx.doi.org/10.1016/j.ejrad.2016.01.021DOI Listing
April 2016

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

Eur Radiol 2016 Jun 3;26(6):1905-12. Epub 2015 Sep 3.

High Field MR Centre, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria.

Objectives: To assess the clinical relevance of T2 relaxation times, measured by 3D triple-echo steady-state (3D-TESS), in knee articular cartilage compared to conventional multi-echo spin-echo T2-mapping.

Methods: 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 T2 mapping, and 3D TESS with the same geometry settings, but variable acquisition times: standard (TESSs 4:35min) and quick (TESSq 2:05min). T2 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.

Results: The mean quantitative T2 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).

Conclusions: 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 B1 and B0 changes.

Key Points: • 3D-TESS T 2 mapping provides clinically comparable results to CPMG in shorter scan-time. • Clinical and investigational studies may benefit from high temporal resolution of 3D-TESS. • 3D-TESS T 2 values are able to differentiate between healthy and damaged cartilage.
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http://dx.doi.org/10.1007/s00330-015-3979-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4863907PMC
June 2016

Cartilage evaluation with biochemical MR imaging using in vivo Knee compression at 3T-comparison of patients after cartilage repair with healthy volunteers.

J Biomech 2015 Sep 30;48(12):3349-55. Epub 2015 Jun 30.

High Field MR Centre, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna/Vienna General Hospital, Waehringer Guertel 18-20, A-1090 Vienna, Austria; Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, Austrian Cluster for Tissue Regeneration, Donaueschingenstraße 13, A-1200 Vienna, Austria.

Magnetic resonance (MR) transverse relaxation time (T2) mapping has been frequently used to evaluate collagen content and its organization. In this study, MR T2 mapping, using the multi-slice, multi-echo Carr-Purcell-Meiboom-Gill technique, was performed in volunteers and patients after matrix-associated autologous chondrocyte transplantation (MACT) under unloading and loading conditions with an MR-compatible compression device. In the volunteer study, a statistically significant decrease in the cartilage MR T2 values was observed during the loading phase when compared to the initial load-free measurement. During the recovery period, a statistically significant increase in the T2 values was found in the central superficial layer (p=0.001), the central deep layer (p=0.005), the posterior deep layer (p=0.001), and in the tibia superficial layer (p=0.01) when compared to measurements under loading. In patients after MACT, during unloading or loading conditions, statistically significant changes in T2 values were observed in the transplant deep zone (p=0.005), in the posterior deep zone (p=0.004), and in the tibia superficial zone (p=0.012). The results of this study show that MR T2 mapping under loading conditions may provide additional information about cartilage repair tissue composition and organization during the postoperative follow-up, and may help to evaluate the efficacy of cartilage-repair surgery techniques.
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http://dx.doi.org/10.1016/j.jbiomech.2015.06.016DOI Listing
September 2015

Evaluation of cartilage repair and osteoarthritis with sodium MRI.

NMR Biomed 2016 Feb 23;29(2):206-15. Epub 2015 Mar 23.

High-Field MR Center, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna/Vienna General Hospital, Vienna, Austria.

The growing need for early diagnosis and higher specificity than that which can be achieved with morphological MRI is a driving force in the application of methods capable of probing the biochemical composition of cartilage tissue, such as sodium imaging. Unlike morphological imaging, sodium MRI is sensitive to even small changes in cartilage glycosaminoglycan content, which plays a key role in cartilage homeostasis. Recent advances in high- and ultrahigh-field MR systems, gradient technology, phase-array radiofrequency coils, parallel imaging approaches, MRI acquisition strategies and post-processing developments have resulted in many clinical in vivo sodium MRI studies of cartilage, even at 3 T. Sodium MRI has great promise as a non-invasive tool for cartilage evaluation. However, further hardware and software improvements are necessary to complete the translation of sodium MRI into a clinically feasible method for 3-T systems. This review is divided into three parts: (i) cartilage composition, pathology and treatment; (ii) sodium MRI; and (iii) clinical sodium MRI studies of cartilage with a focus on the evaluation of cartilage repair tissue and osteoarthritis.
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http://dx.doi.org/10.1002/nbm.3280DOI Listing
February 2016

Clinical applications at ultrahigh field (7  T). Where does it make the difference?

NMR Biomed 2016 09 12;29(9):1316-34. Epub 2015 Mar 12.

Vascular and Abdominal Imaging, Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Mannheim, Germany.

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 (B0 ) 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 (31) 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. Copyright © 2015 John Wiley & Sons, Ltd.
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http://dx.doi.org/10.1002/nbm.3272DOI Listing
September 2016

Neuronal marker recovery after Simvastatin treatment in dementia in the rat brain: in vivo magnetic resonance study.

Behav Brain Res 2015 May 16;284:257-64. Epub 2015 Feb 16.

Slovak University of Technology in Bratislava, Faculty of Chemical and Food Technology, Institute of Analytical Chemistry, Bratislava, Slovak Republic. Electronic address:

The aim of study was to search for new biomarkers with a magnetic resonance technique to identify the early stages of dementia, induced by D-galactose, and evaluate Simvastatin therapy. Localized proton magnetic resonance spectroscopy measurements showed a significant decrease in the concentration of N-acetylaspartate+N-acetylaspartylglutamate and myo-inositol in the D-galactose group compared to the control group, and, conversely, an increase of N-acetylaspartate+N-acetylaspartylglutamate in the D-galactose/Simvastatin group. Using a saturation transfer experiment, with phosphorus magnetic resonance spectroscopy, we observed a significant elevation of the forward rate constant of the creatine kinase reaction in the brains of the D-galactose group compared to controls, and subsequently, a significant reduction of this reaction in the D-galactose/Simvastatin group. Spatial learning and memory were evaluated using the modified Morris water maze test. The dynamics of the learning process represented by the learning index revealed a significant reduction in learning in the D-galactose group, but the deficits as a consequence of the D-galactose effects were recovered in the D-galactose/Simvastatin group, in which the learning dynamics resembled those of the control group. By determining the thiobarbituric acid reactive substances and total coenzyme Q9 in plasma, we have shown that long-term administration of D-galactose created conditions for oxidative stress, and that the administration of Simvastatin decreased oxidative stress in plasma. Volumetry analyses from the hippocampal area show a reduction in the segmented area in the D-galactose group, compared with the control group, and an enlarged area in the hippocampus in the d-galactose/Simvastatin group.
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http://dx.doi.org/10.1016/j.bbr.2015.02.016DOI Listing
May 2015

Multiparametric MR Imaging Depicts Glycosaminoglycan Change in the Achilles Tendon during Ciprofloxacin Administration in Healthy Men: Initial Observation.

Radiology 2015 Jun 4;275(3):763-71. Epub 2015 Feb 4.

From the MR Centre of Excellence, Department of Biomedical Imaging and Image-Guided Therapy 7F (V.J., P.S., J.V., B.H., M.W., S.T.), and Department of Internal Medicine III, Division of Endocrinology and Metabolism (Y.W., P.W., A.L.), Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria; and Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia (V.J., P.S.).

Purpose: To determine if quantitative magnetic resonance (MR) imaging techniques (sodium MR imaging, glycosaminoglycan [GAG] chemical exchange saturation transfer [CEST], and T2* mapping) could be used as potential markers for biochemical changes in the Achilles tendon induced by ciprofloxacin intake.

Materials And Methods: The ethics committee of the Medical University of Vienna approved the protocol (number 1225/2012), and all patients gave written informed consent. Fourteen ankles from seven men (mean age, 32 years ± 12 [standard deviation]) were included in the study. All patients underwent 7-T MR imaging examinations of the Achilles tendon at baseline and 10 days and 5 months after ciprofloxacin intake. Sodium signal and T2* maps were acquired with the variable echo-time sequence and the GAG CEST values were acquired with a three-dimensional radiofrequency spoiled gradient-recalled-echo sequence.

Results: The mean sodium signal was significantly decreased by 25% in the whole tendon (from baseline to 10 days after ciprofloxacin intake, 130 arbitrary units [au] ± 8 to 98 au ± 5, respectively; P = .023) and returned to baseline after 5 months (116 au ± 10), as observed also at the tendon insertion (baseline, 10 days after ciprofloxacin intake, and 5 months after ciprofloxacin intake, 134 au ± 8, 105 au ± 5, and 119 au ± 9, respectively; P = .034). The mean GAG CEST value in the whole tendon was parallel to the sodium signal with a decrease from baseline to 10 days after ciprofloxacin intake, 4.74% ± 0.75 to 4.50% ± 0.23, respectively (P = .028) and an increase at 5 months after ciprofloxacin intake to 4.88% ± 1.02.

Conclusion: In conclusion, this study demonstrates a ciprofloxacin-induced reversible reduction of the normalized sodium MR imaging signal and the GAG CEST effect in the Achilles tendon of healthy volunteers. Changes in sodium MR imaging and GAG CEST in men may reflect a decrease of GAG content in the Achilles tendon after ciprofloxacin intake.
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http://dx.doi.org/10.1148/radiol.15140484DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4441530PMC
June 2015

Use of diagnostic dynamic contrast-enhanced (DCE)-MRI for targeting of soft tissue tumour biopsies at 3T: preliminary results.

Eur Radiol 2015 Jul 11;25(7):2041-8. Epub 2015 Jan 11.

Department of Biomedical Imaging and Image-guided Therapy, Division of Neuroradiology and Musculoskeletal Radiology, Medical University of Vienna, Vienna, Austria,

Objectives: To test the feasibility and accuracy of MR-guided soft tissue tumour biopsy at 3T, using the dynamic contrast-enhanced (DCE) information from staging MRI for intralesional targeting.

Methods: After obtaining written informed consent for this institutional review board-approved study, 53 patients with suspected soft tissue tumours prospectively underwent preoperative staging MRI at 3T, including DCE, and subsequent MR-guided core needle biopsy. In 44/53 cases, DCE was heterogeneous and was used for intralesional biopsy targeting. Surgical, whole-specimen histology was used as the gold standard in 43/44 patients and revealed 42 soft tissue tumours (24 men; 18 women; mean age, 52 years; range, 19 - 84).

Results: Final surgical histology revealed eight benign lesions, six tumours of intermediate dignity, and 28 malignancies. All malignancies had shown heterogeneous DCE. The diagnostic yield of the biopsies was 100% (42/42). Histological accuracy rates of biopsy were 100% in predicting the dignity (42/42; 95% CI [0.916 - 1.000]), 95.2% for the tissue-specific entity (40/42; 95% CI [0.847 - 0.987]), and 90.5% for the tumour grade (38/42; 95% CI [0.779 - 0.962]).

Conclusions: Our preliminary study indicates that biopsy of soft tissue tumours can be performed accurately and safely with DCE targeted MR-guidance at 3T, using a combined staging/biopsy MRI protocol.

Key Points: • MR-guided soft tissue tumour biopsy using DCE for intralesional targeting is feasible. • Targeting by staging-MRI allows reliable planning of the biopsy approach. • The method seems accurate and safe as a combined staging/biopsy procedure in outpatients. • DCE-targeted biopsy seems useful in challenging large and heterogeneous tumours.
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http://dx.doi.org/10.1007/s00330-014-3576-0DOI Listing
July 2015

Delayed gadolinium-enhanced MRI of the fibrocartilage disc of the temporomandibular joint--a feasibility study.

Magn Reson Imaging 2014 Dec 15;32(10):1223-9. Epub 2014 Aug 15.

High Field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria; Austrian Cluster for Tissue Regeneration, Ludwig Boltzmann Institute for Clinical and Experimental Traumatology, Donaueschingenstraße 13, 1200 Vienna, Austria.

Objective: To 1) test the feasibility of delayed Gadolinium-Enhanced Magnetic Resonance Imaging of Cartilage (dGEMRIC) at 3 T in the temporomandibular joint (TMJ) and 2) to determine the optimal delay for measurements of the TMJ disc after i.v. contrast agent (CA) administration.

Design: MRI of the right and left TMJ of six asymptomatic volunteers was performed at 3 T using a dedicated coil. 2D inversion recovery (2D-IR) sequences were performed at 4 time points covering 120 minutes and 3D gradient-echo (3D GRE) dual flip-angle sequences were performed at 14 time points covering 130 minutes after the administration of 0.2 mmol/kg of Gd-diethylenetriamine pentaacetic acid ion (Gd-DTPA)(2-), i.e., 0.4 mL of Magnevist™ per kg body weight. Pair-wise tests were used to assess differences between pre-and post-contrast T1 values.

Results: 2D-IR sequences showed a statistically significant drop (p<0.001) in T1 values after i.v. CA administration. The T1 drop of 50% was reached 60 minutes after bolus injection in the TMJ disc. The 3D GRE dual flip-angle sequences confirmed these results and show plateau of T1 after 60 minutes.

Conclusions: T1(Gd) maps calculated from dGEMRIC data allow in vivo assessment of the fibrocartilage disc of the TMJ. The recommended measurement time for dGEMRIC in the TMJ after i.v. CA administration is from 60 to 120 minutes.
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http://dx.doi.org/10.1016/j.mri.2014.08.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4228050PMC
December 2014

Sodium MR Imaging of Articular Cartilage Pathologies.

Curr Radiol Rep 2014 20;2:41. Epub 2014 Feb 20.

High Field MR Center, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria.

Many studies have proved that noninvasive sodium MR imaging can directly determine the cartilage GAG content, which plays a central role in cartilage homeostasis. New technical developments in the recent decade have helped to transfer this method from in vitro to pre-clinical in vivo studies. Sodium imaging has already been applied for the evaluation of cartilage and repair tissue in patients after various cartilage repair surgery techniques and in patients with osteoarthritis. These studies showed that this technique could be helpful not only for assessment of the cartilage status, but also predictive for osteoarthritis. However, due to the low detectable sodium MR signal in cartilage, sodium imaging is still challenging, and further hardware and software improvements are necessary for translating sodium MR imaging into clinical practice, preferably to 3T MR systems.
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http://dx.doi.org/10.1007/s40134-014-0041-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3963441PMC
February 2014

Biochemical analysis of the articular disc of the temporomandibular joint with magnetic resonance T2 mapping: a feasibility study.

Clin Oral Investig 2014 Sep 5;18(7):1865-71. Epub 2013 Dec 5.

Department of Prosthodontics, Bernhard Gottlieb University of Dentistry, Medical University of Vienna, Sensengasse 2a, 1090, Vienna, Austria,

Objectives: Symptoms of temporomandibular joint (TMJ) dysfunction can seriously compromise patients' quality of life. The aim of our study was to use magnetic resonance imaging (MRI) T2 mapping of the articular disc to determine whether T2 mapping of the TMJ disc is feasible in routine clinical imaging and to assess the normal T2 relaxation time distribution within the TMJ.

Methods: Included were ten asymptomatic volunteers without pain, any mouth-opening limitations, or any clicking phenomena. MR imaging was performed on a 3-T MR scanner using a flexible, dedicated, eight-channel multielement coil. T2 mapping was performed in the oblique sagittal plane. The regions of interest (ROIs) for the T2 relaxation time maps of the disc were selected manually.

Results: The mean values for ROIs ranged between 22.4 and 28.8 ms, and the mean for all ROIs was 26.0 ± 5.0 ms. Intraclass correlation (ICC) for interobserver variability was 0.698, and ICC for intraobserver variability was 0.861. There was no statistically significant difference between raters (p = 0.091) or sides (p = 0.810).

Conclusion: The T2 mapping technique enables ultrastructural analysis of the composition of TMJ disc. This biochemical technique is feasible in vivo, as shown in our study, when a high-field (3 T) MR and a dedicated TMJ coil are used.

Clinical Relevance: T2 mapping as a biochemical technique, together with morphological MRI, may help to gain more insights into the physiology and into the pathophysiology of the articular disc in the TMJ noninvasively and in vivo.
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http://dx.doi.org/10.1007/s00784-013-1154-5DOI Listing
September 2014

Bi-exponential T2 analysis of healthy and diseased Achilles tendons: an in vivo preliminary magnetic resonance study and correlation with clinical score.

Eur Radiol 2013 Oct 13;23(10):2814-22. Epub 2013 Jun 13.

Center of Excellence for High field MR, Department of Radiology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090, Vienna, Austria,

Objective: To compare mono- and bi-exponential T2 analysis in healthy and degenerated Achilles tendons using a recently introduced magnetic resonance variable-echo-time sequence (vTE) for T2 mapping.

Methods: Ten volunteers and ten patients were included in the study. A variable-echo-time sequence was used with 20 echo times. Images were post-processed with both techniques, mono- and bi-exponential [T2 m, short T2 component (T2 s) and long T2 component (T2 l)]. The number of mono- and bi-exponentially decaying pixels in each region of interest was expressed as a ratio (B/M). Patients were clinically assessed with the Achilles Tendon Rupture Score (ATRS), and these values were correlated with the T2 values.

Results: The means for both T2 m and T2 s were statistically significantly different between patients and volunteers; however, for T2 s, the P value was lower. In patients, the Pearson correlation coefficient between ATRS and T2 s was -0.816 (P = 0.007).

Conclusion: The proposed variable-echo-time sequence can be successfully used as an alternative method to UTE sequences with some added benefits, such as a short imaging time along with relatively high resolution and minimised blurring artefacts, and minimised susceptibility artefacts and chemical shift artefacts. Bi-exponential T2 calculation is superior to mono-exponential in terms of statistical significance for the diagnosis of Achilles tendinopathy.

Key Points: • Magnetic resonance imaging offers new insight into healthy and diseased Achilles tendons • Bi-exponential T2 calculation in Achilles tendons is more beneficial than mono-exponential • A short T2 component correlates strongly with clinical score • Variable echo time sequences successfully used instead of ultrashort echo time sequences.
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http://dx.doi.org/10.1007/s00330-013-2897-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3769589PMC
October 2013