PubMed · 14192846
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G BRECHER. 1964-07-09. RADIATION BLEEDING.. https://doi.org/10.1111/j.1749-6632.1964.tb50687.x
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Magnetic resonance imaging (MRI) has greatly advanced evaluation of marrow diseases of the paediatric skeleton. As with many other aspects of paediatric radiology it is important to recognize the normal variations in the appearance of the marrow that occur in the growing child. These normal variations need to be differentiated from diseases and conditions that affect the marrow. This review describes the normal changes that occur in children with age, and the appearances of the pathological changes seen in infection, infiltration, haematological disorders, transplantation and radiation therapy.
OBJECTIVE: The purpose of this study was to describe a largely observer-independent computer-assisted method for accurate quantitative analysis of bone marrow edema. MATERIALS AND METHODS: Ten patients with bone marrow edema of the knee were included in the study. Coronal STIR images of the affected knees were obtained using a 1.0-T MR scanner. Size and signal intensity of the bone marrow edema were assessed on the basis of gray-scale value analysis and calculation of a threshold value for differentiating normal and edematous bone marrow. All measurements were carried out three times for statistical analysis. RESULTS: The intraobserver coefficient of variation was 0.89% for the volume and 0.94% for the signal intensity of the bone marrow edema, showing the small impact of manual interference on results produced with this method. CONCLUSION: A computer-assisted method for quantification of bone marrow edema has been described. Intraobserver variation was very low, indicating excellent reproducibility of results. Although the method is too time-consuming for clinical use, it is recommended for research purposes.
Myelodysplastic syndromes, a heterogeneous group of clonal stem cell disorders, are characterized by ineffective and dysplastic hematopoiesis and increased risk of leukemic transformation. The clonal disorder may result in cumulative cytogenetic abnormalities in a multistep process. Intrinsic and extrinsic factors contributing to ineffective hematopoiesis include genetic predisposition, environmental effects, and iatrogenic causes. The common and often overlapping features of myelodysplastic syndrome, aplastic anemia, T-cell large granular lymphocyte lymphoproliferative disorder, and paroxysmal nocturnal hemoglobinuria suggest a shared pathophysiologic mechanism of marrow failure. Recent studies suggest that dominant clonal T cells, which may be driven to expand by hematopoietic antigenic stimuli, result in the T-cell-mediated inhibition of hematopoietic progenitors, thus contributing to cytopenia.