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Die aseptische Femurkopfnekrose (aFKN) ist im Fruhstadium mittels Radiographie schwierig zu diagnostizieren. Da sie zudem nicht selten klinisch okkult ist, bietet der fruhzeitige Einsatz der Magnetresonanztomographie (MRT) die einzige Moglichkeit, einen klinischen Verdacht zu verifizieren oder auszuraumen. Die MRT und in einzelnen Fallen die erganzende Computertomographie sind heute die Eckpfeiler der Diagnose und auch der Klassifikation der aFKN. Die Radiographie des Beckens in der a.-p.-Projektion und einer zweiten Ebene der betroffenen Hufte dient zwar weiterhin als Basisuntersuchung beim Verdacht auf eine aFKN, hat ihre Bedeutung aber in der Verlaufskontrolle und dem Ausschluss anderer Erkrankungen. Inzwischen ist unbestritten, dass die Entscheidung zur bestmoglichen Therapie von einer genauen Klassifikation der Erkrankung abhangt. In der S3-Leitlinie zur Diagnostik und Therapie der aFKN wird dabei in Deutschland die Verwendung der ARCO-Klassifikation empfohlen. Die vorliegende Ubersichtsarbeit vermittelt den aktuellen Stand der Diagnostik und Klassifikation der aFKN des Erwachsenenalters. Dabei werden die Kriterien fur die Einordnung in die einzelnen ARCO-Stadien definiert und kritisch kommentiert.

Objectives To evaluate the clinical feasibility of ultrahigh field 7-T SWI to visualize vessels and assess their density in the immature epiphyseal cartilage of human knee joints. Methods 7-T SWI of 12 knees (six healthy volunteers, six patients with osteochondral abnormalities; mean age 10.7 years; 3 female, 9 male) were analysed by two readers, classifying intracartilaginous vessel densities (IVD) in three grades (no vessels, low IVD and high IVD) in defined femoral, tibial and patellar zones. Differences between patients and volunteers, IVDs in different anatomic locations, differences between cartilage overlying osteochondral abnormalities and corresponding normal zones, and differences in age groups were analysed. Results Interrater reliability showed moderate agreement between the two readers (κ = 0.58, p < 0.001). The comparison of IVDs between patients and volunteers revealed no significant difference (p = 0.706). The difference between zones in the cartilage overlying osteochondral abnormalities to corresponding normal zones showed no significant difference (p = 0.564). IVDs were related to anatomic location, with decreased IVDs in loading areas (p = 0.003). IVD was age dependent, with more vessels present in the younger participants (p = 0.001). Conclusions The use of SWI in conjunction with ultrahigh field MRI makes the in vivo visualization of vessels in the growing cartilage of humans feasible, providing insights into the role of the vessel network in acquired disturbances. Key Points • SWI facilitates in vivo visualization of vessels in the growing human cartilage. • Interrater reliability of the intracartilaginous vessel grading was moderate. • Intracartilaginous vessel densities are dependent on anatomical location and age. Electronic supplementary material The online version of this article (10.1007/s00330-017-5290-1) contains supplementary material, which is available to authorized users.

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.

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.

The update of the German S3 guideline on atraumatic femoral head necrosis in adults aims to provide an overview of diagnosis and treatment. All clinical studies, systematic reviews, and meta-analyses published in German or English between 01.05.2013 and 30.04.2017 were included. Of 427 studies, 28 were suitable for analysis. Risk factors are corticosteroids, chemotherapy, kidney transplants, hemoglobinopathies, and alcoholism. Differential diagnoses are for example bone marrow edema, insufficiency fracture, and destructive arthropathy. Radiography should be performed upon clinical suspicion. In patients with normal radiography findings but persistent complaints, magnetic resonance imaging (ARCO classification) is the method of choice. Computed tomography (CT) can be used to confirm/exclude articular surface collapse. A subchondral sclerosis zone30% in CT indicates a better prognosis. Left untreated, a subchondral fracture will develop within 2 years. The risk of disease development in the opposite side is high during the first 2 years, but unlikely thereafter. In conservative therapy, iloprost and alendronate can be used in a curative approach, the latter for small, primarily medial necrosis. Conservative therapy alone as well as other drug-based and physical approaches are not suitable for treatment. No particular joint-preserving surgery can currently be recommended. Core decompression should be performed in early stages with30% necrosis. From ARCO stage IIIc or in stage IV, the indication for total hip arthroplasty should be checked. Results after total hip arthroplasty are comparable with those after coxarthrosis, although the revision rate is higher due to the relatively young age of patients. Statements on the effectiveness of cell-based therapies such as expanded stem cells or bone marrow aspirates cannot currently be made.

Das Update der S3-Leitlinie der atraumatischen Femurkopfnekrose (aFKN) des Erwachsenen soll einen aktualisierten Uberblick zu Diagnostik und Therapie geben. Eingeschlossen wurden vom 01.05.2013 bis 30.04.2017 publizierte deutsch- und englischsprachige klinische Studien, systematische Reviews und Metaanalysen. Von 427 Studien waren 28 zur Auswertung geeignet. Risikofaktoren sind Kortikoide, Chemotherapie, Nierentransplantationen, Hamoglobinopathien und Alkoholismus. Differenzialdiagnosen sind u. a. Knochenmarkodeme, Insuffizienzfraktur und destruierende Arthropathie. Bei klinischem Verdacht soll eine Rontgenuntersuchung erfolgen. Bei unauffalligem Rontgenbild und anhaltenden Beschwerden ist die Magnetresonanztomographie (ARCO-Klassifikation) die Methode der Wahl. Ein Gelenkflacheneinbruch sollte bei Zweifeln in der Computertomographie abgeklart werden. Eine subchondrale Sklerosezone von >30 % im CT zeigt eine bessere Prognose an. Unbehandelt entwickelt sich innerhalb von 2 Jahren eine subchondrale Fraktur. Das Risiko des Befalls der Gegenseite ist die ersten 2 Jahre hoch, danach unwahrscheinlich. Im Rahmen der konservativen Therapie konnen Iloprost und Alendronat als Heilversuch zum Einsatz kommen, Alendronat bei kleineren, vorwiegend medial gelegenen Nekrosen. Die alleinige konservative Therapie sowie andere medikamentose und physikalische Masnahmen sind zur Behandlung nicht geeignet. Ein bestimmter gelenkerhaltender Eingriff kann derzeit nicht empfohlen werden. Die Entlastungsbohrung soll in fruhen Stadien bei Nekrosen

Background: Although commonly proposed to be the starting point of juvenile osteochondritis dissecans (JOCD), avascular osteonecrosis (AVN) has been an inconsistent finding in histological studies. Analysis of early-stage lesions is required to elucidate the origins of OCD and justify proper treatment. Purpose: To analyze histological sections of JOCD lesions with special emphasis on bone vitality. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Of 64 patients with 74 JOCD lesions (20 females, mean age, 11.4 years; 44 males, mean age, 12.7 years), 34 required surgery because of lesion instability or failed nonoperative treatment. From 9 patients, 11 histological specimens were obtained. Lesions were classified according to the International Cartilage Repair Society (ICRS). Two additional histological control sections were harvested from children without JOCD manifestation. Undecalcified histological sections were histomorphometrically analyzed. To analyze the skeletal health of the patients, biochemical analyses with special emphasis on bone metabolism were performed. Results: Histologically, no osteonecrosis was visible in any of the cases. Osteocyte distribution was similar among OCD lesions and controls. ICRS OCD I lesions (n = 6) showed no intralesional separation. In ICRS OCD II and III lesions (n = 5), there was a subchondral fracture concomitant with histological characteristics of active repair mechanism (increased bone formation: osteoid volume P = .008, osteoblast number P = .046; resorption: osteoclast number P = .005; and tissue fibrosis compared with controls). Instead, in ICRS OCD I lesions, subchondral osteoid volume ( P = .010) and osteoblast number ( P = .046) were significantly increased compared with controls; however, no active repair mechanisms (no increased bone resorption or fibrous tissue) were detected, suggesting a focal lack of mineralization. Fifty-seven of 64 patients (89.1%) showed a vitamin D deficiency. The median vitamin D serum level of the patients with ICRS OCD I lesions was 13.6 µg/L. Conclusion: In the present study, osteonecrosis was not found in histological specimens of JOCD. As a secondary finding, focal accumulations of nonmineralized bone matrix indicating a lack of mineralization in ICRS OCD I lesions were revealed. This finding correlated with a low level of vitamin D in the affected children.

The goal of this work was to analyze the clinical and technical usability of recently introduced steady state free precession T 2 mapping technique. The TESS-T 2 values were compared to conventionally used multi-echo spin-echo sequence (usually referred to as CPMG). The results showed that although T 2 values determined by TESS are lower than those of CPMG, they are highly correlated between two methods. Both, clinical and experimental studies might benefit from the speed of the 3D-TESS. The results of this study showed the clinical usability of a 3D-TESS sequence for T 2 mapping of human articular knee cartilage. 3D-TESS provides highly correlated T2-values to conventional CMPG sequence with some additional benefits, such as dramatic shortening of acquisition time andfair insensitivity to B 1 and B 0 variations. Also, T 2 values acquired with 3D-TESS can differentiate between reference and impaired cartilage.

Purpose To assess the potential clinical utility of in vivo susceptibility-weighted imaging and quantitative susceptibility mapping of growth cartilage in the juvenile human knee at 7 T. Methods High-resolution gradient-echo images of the knees of six healthy children and adolescents aged 6 to 15 were acquired with a 28-channel coil at 7 T. Phase images from the coils were combined using a short echo-time reference scan method (COMPOSER). Results Veins oriented perpendicular to the static B0 field appeared doubled in susceptibility-weighted imaging, but not quantitative susceptibility mapping. Veins and layers in the cartilage were visible in all children up to the age of 13. Conclusions Phase imaging using susceptibility-weighted imaging and quantitative susceptibility mapping allows the in vivo visualization of veins and layers in human growth cartilage. Magn Reson Med, 2017. © 2017 International Society for Magnetic Resonance in Medicine.

Osteofibrous dysplasia Campanacci is a rare benign bone tumor most frequently observed in young childhood. The exclusive localization in the tibia is very characteristic. The incidence of congenital primary bone tumors is an absolute rarity. We report a case of a newborn with a histologically proven osteofibrous dysplasia Campanacci at the tibia presenting a regular radiographic follow-up. After a small open biopsy and spontaneous minor fracture, the lesion rapidly remodeled within 1½ months and almost completely regressed with restutio ad integrum. Surgical intervention in this tumor entity at childhood age has been shown to have a high recurrence rate but due to lack of experience with newborns, guidelines do not exist. We analyze the radiologic and histologic differential diagnosis of juvenile adamantinoma and emphasize that congenital peripheral bone tumors should be treated conservatively when malignancy is excluded.

Ultra-high-field magnetic resonance (UHF MR) systems (7 Tesla [7 T] and higher field strength) are expected to yield a twofold-to-threefold improvement in image signal-to-noise ratio (SNR) over 3 Tesla (3 T) MR scanners. Advances in multichannel radiofrequency (RF) technology provide an additional twofold-to-sixfold improvement in SNR over single-channel RF coils (Wiggins et al., 2005). Many fields require new methods to deal with increased B0 and B1 inhomogeneity, however, and sequences need to be modified to adapt to modified relaxation times of 1H and X nuclei at 7 T. In the following sections, we review the state of the art of 7 T methods and nascent applications in neuroimaging, musculoskeletal (MSK) imaging, studies of metabolism, and oncology.