الفهرس 
Pathology And Magnetic Resonance Imaging Manifestations Of Pediatric Bone Tumors
Benign periosteal reactionOnly 14 pages are availabe for public view
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Abstract
The term bone tumor is a broad category, which includes neoplasms and tumor-like conditions. The neoplastic processes can be categorized as benign and malignant, and the latter may be subcategorized as primary and secondary. It is estimated that benign tumors are ten times more common than primary malignant tumors
Development of new surgical techniques and treatments for skeletal tumors has resulted in the need for a way to accurately evaluate patients with bone tumors in the staging phase and after therapy.
Advanced MR imaging techniques, together with conventional MR imaging, the clinical history of the patient, and other imaging methods, are important tools for analyzing and diagnosing bone tumors, avoiding unnecessary biopsies, facilitating early and efficient treatment, and consequently enhancing patient outcomes.
The purpose of this study was to elucidate the role of advanced techniques of MRI in diagnosis of pediatric bone tumors and to assess the diagnostic potential of MR-DCE in conjunction with MR-DWI in differentiating benign from malignant bone tumors.
DWI allows quantitative and qualitative analyses of tissue cellularity and cell membrane integrity and has been widely used for tumor detection and characterization and to monitor treatment response.
In our study we have found that, the ADC values of solid malignant tumors (n= 8) ranged from 0.4 to 1.5 x 10-3 mm2/s with mean ADC (0.78 x 10-3 mm2/s) were significantly lower than that of the benign bony tumors (n=22) which ranged from 1.26 to 2.6 x 10-3 mm2/s, with the mean ADC value about (1.69 x 10-3 mm2/s).
Our results according to ROC curve for the discrimination between benign and malignant bone lesions using the ADC value showed that the best cut-off value is ADC of <0.9 with overall sensitivity 100%, specificity 100%, and accuracy 100%, and this means that ≤ 0.9 indicates malignant result while > 0.9 is defined as benign result.
DCE imaging provides physiologic information that cannot be determined from conventional MR imaging, including information regarding tissue vascularization, perfusion and capillary permeability.
The main contributions of dynamic MRI are identification and characterization of viable tumour, sites to guide the biopsy and monitoring of preoperative chemotherapy.
In our study we have found that, the benign bone tumors (n= 22) showed type II TIC curve, malignant bone tumors (n= 8); five of them showed type IV curve, two of them after chemotherapy showed type V curve, and the last one showed type II curve which is a false negative result.
In our study Receiver operating characteristics (ROC) curve was used to get out the sensitivity of the dynamic study which was 75%, with specificity of 100% and diagnostic accuracy of 93.3% as regards the discrimination between benign and malignant bone tumors.