Chondroblastoma and clear cell chondrosarcoma: radiological and MRI characteristics with histopathological correlation

Abstract. : Objective: To analyze and compare the radiological and magnetic resonance imaging (MRI) appearances of chondroblastoma and clear cell chondrosarcoma with histopathological correlation. Design and patients: Twelve patients with histologically proven chondroblastoma and of another four patients with clear cell chondrosarcoma were investigated by radiographs and MRI (T1-, T2-weighted sequences, intravenous gadolinium application). Additionally, the clinical and radiologic data of seven cases of clear cell chondrosarcoma without available MRI were considered. The localization, calcification of tumor matrix, periosteal reaction, cortical bone and patterns of bone destruction were analyzed according to the Lodwick radiological grading system (LRGS). The signal intensity on T1- and T2-weighted sequences, characteristics of contrast enhancement, associated bone marrow edema, soft tissue reaction and joint involvement were evaluated. Histopathological specimens were available in all cases. Results: The age of patients with chondroblastoma (range 15-59years, mean 22.3years) was lower than that of those with clear cell chondrosarcoma (range 19-61years, mean 36.6years), and the lesions were smaller in the chondroblastoma group (range 1-4cm, mean 2.3cm) than in patients with clear cell chondrosarcoma (range 3-7.5cm, mean 5.2cm). The chondroblastomas were more confined to the epiphysis (10/12) than the clear cell chondrosarcomas. All chondroblastomas and clear cell chondrosarcomas except one were classified as grade 1A or 1B according to the LRGS; one clear cell chondrosarcoma was judged as grade 2. Signal intensity of the tumors on MRI was very heterogeneous in both groups. High signal intensity on T2-weighted MR images in chondroblastoma mostly corresponded to areas with aneurysmal bone cyst components and in clear cell chondrosarcoma to islands of hyaline cartilage. Contrast enhancement occurred in all tumors and tended to be more intense with clear cell chondrosarcoma. Chondroblastoma was more frequently associated with bone marrow edema (11/12), periosteal reaction (10/12), soft tissue reaction (7/12) and synovitis (3/12). Conclusion: Chondroblastoma occurs in younger patients, is smaller than clear cell chondrosarcoma and is more confined to the epiphysis. The overlap of signal intensity and contrast enhancement patterns does not allow a reliable differentiation of the two tumors by MRI. Chondroblastomas are typically associated with bone marrow edema, periosteal reaction and soft tissue reactio

A comparison of subchondral bone mineralization between the glenoid cavity and the humeral head on 57 cadaverous shoulder joints

Purpose: Mineralization distribution of the subchondral bone plate can be used as a marker for long-term stress distribution in diarthrodial joints. Severe injuries or pathological changes of the glenohumeral joint often end in osteoarthritis, where shoulder arthroplasty has become the treatment of choice. The computed tomography osteoabsorptiometry (CT-OAM) is a non-invasive method to determine the distribution of the mineralization of the subchondral bone plate in vivo, which is an important factor concerning the implantation of orthopedic endoprostheses. The aim of this study was to investigate the mineralization of both joint partners of the glenohumeral joint and to compare them with each other. Methods: The distribution of the mineralization of the subchondral bone plate of 57 shoulder specimens was determined by means of CT-OAM. To evaluate a correlation between age and localization of subchondral mineralization maxima, the Chi-square test correlation test was applied. Results: Forty-nine glenoid cavities (86%) showed a bicentric mineralization distribution pattern with anterior and posterior maxima, only 8 glenoid cavities (14%) revealed a monocentric mineralization pattern with anterior maxima. Forty-five humeral heads (79%) showed a bicentric distribution pattern with anterior and posterior maxima, 12 humeral heads (21%) could be classified as monocentric with a centro-posterior pronounced maximum. Conclusions: We could demonstrate that stress distribution in both joint partners of the glenohumeral joint is inhomogeneous and characteristically bicentric due to the physiological incongruity. Monocentric mineralization patterns can result as a cause of age-related loss of incongruit

Myositis Ossificans Presenting as a Tumor of the Cervical Paraspinal Muscles

Abstract : Myositis ossificans (MO) is a benign heterotopic bone formation within muscle or soft tissue that is predominantly initiated by trauma. The diagnostic challenge is to distinguish it from bone and soft tissue malignancies. The most common location of MO is the muscles of the thigh and the upper arm, whereas the neck is only rarely involved. A broad range of theories about the etiology of MO exists in the literature, but minor or major trauma can be found in almost every instance. We present a patient in which additional hybrid imaging with singlephoton emission tomography (SPECT) and computed tomography helped to confirm the diagnosis of MO in the paraspinal cervical muscle

Mineralisation and mechanical strength of the glenoid cavity subchondral bone plate

Purpose: Failures in total shoulder replacements are often due to aseptic loosening of the glenoid component; the subchondral bone plate is an important factor governing primary fixation of implant materials. Therefore, we investigated characteristic mineralisation patterns of the subchondral bone plate, which demonstrate long-term stress on articular surfaces, age-related changes, postsurgical biomechanical situations and regions of fixation. Using computed tomography osteo-absorptiometry (CT-OAM), these distribution patterns can be demonstrated in vivo. The aim of this study was to investigate the relationship between subchondral bone-plate mineralisation measured with CT-OAM and the mechanical strength measured by indentation. Methods: A total of 32 cadaverous glenoid cavities were evaluated by CT-OAM and indentation testing. Linear regression was used to compare mineralisation and strength of the subchondral bone plate. Results: Results showed two patterns of mineralisation distribution. Twenty-eight cavities were related to bicentric distribution pattern and four showed a single maximum. The correlation coefficient between CT-OAM density and subchondral bone-plate strength was determined to be between 0.62 and 0.96 (P < 0.02). Conclusions: Long-term stress affects not only the subchondral but also the underlying cancellous bone. It therefore can be assumed that mineralisation patterns of the subchondral bone plate continue in cancellous bone. Areas of high density could serve as anchoring locations for orthopaedic implants in resurfacing the glenoid cavit

Image Fusion for Intraoperative Control of Axis in Long Bone Fracture Treatment

Abstract : Background: : The incidence of malalignment after long bone fracture fixation is reported to be between 0 and 37%. Modern fracture treatment strives towards closed reduction and minimally invasive fracture fixation, thus not exposing the fracture itself. Hence, the occurrence of malalignment might even be higher than previously reported and quite frequently even necessitate secondary operations. Minimally invasive techniques rely heavily on intraoperative fluoroscopy. However, fluoroscopic images have small cross-sections and consequently limit intraoperative visualization of the limb to individual segments only. Under these circumstances, correct alignment of fragments in long bone fractures is often compromised. Methods: : We present a new software prototype using an absolute reference panel to concatenate two or more discontinuous fluoroscopic images into one single panoramic picture. The reference panel is placed on the operating table under the limb to be examined. Prior to digital picture fusion, the software applies non-linear distortion, picture scaling and de-rotation algorithms to the fluoroscopic images. Results: : The presented software runs on a notebook and processes images generated by a commercially available mobile C-arm within seconds. The reliability of alignment in the panorama picture is found to be numerically adequate and the technique appropriate for clinical use. Conclusion: : This method aims to improve the intraoperative visualization in minimally invasive osteosynthesis and therefore diminish malalignments in long bone fracture treatmen

Gene expression profiling reveals consistent differences between clinical samples of human leukaemias and their model cell lines

Microarray gene expression profiles of fresh clinical samples of chronic myeloid leukaemia in chronic phase, acute promyelocytic leukaemia and acute monocytic leukaemia were compared with profiles from cell lines representing the corresponding types of leukaemia (K562, NB4, HL60). In a hierarchical clustering analysis, all clinical samples clustered separately from the cell lines, regardless of leukaemic subtype. Gene ontology analysis showed that cell lines chiefly overexpressed genes related to macromolecular metabolism, whereas in clinical samples genes related to the immune response were abundantly expressed. These findings must be taken into consideration when conclusions from cell line-based studies are extrapolated to patients

Image fusion for intraoperative control of axis in long bone fracture treatment

Abstract : Background: : The incidence of malalignment after long bone fracture fixation is reported to be between 0 and 37%. Modern fracture treatment strives towards closed reduction and minimally invasive fracture fixation, thus not exposing the fracture itself. Hence, the occurrence of malalignment might even be higher than previously reported and quite frequently even necessitate secondary operations. Minimally invasive techniques rely heavily on intraoperative fluoroscopy. However, fluoroscopic images have small cross-sections and consequently limit intraoperative visualization of the limb to individual segments only. Under these circumstances, correct alignment of fragments in long bone fractures is often compromised. Methods: : We present a new software prototype using an absolute reference panel to concatenate two or more discontinuous fluoroscopic images into one single panoramic picture. The reference panel is placed on the operating table under the limb to be examined. Prior to digital picture fusion, the software applies non-linear distortion, picture scaling and de-rotation algorithms to the fluoroscopic images. Results: : The presented software runs on a notebook and processes images generated by a commercially available mobile C-arm within seconds. The reliability of alignment in the panorama picture is found to be numerically adequate and the technique appropriate for clinical use. Conclusion: : This method aims to improve the intraoperative visualization in minimally invasive osteosynthesis and therefore diminish malalignments in long bone fracture treatmen