Differentiation of malignant and benign lesions of the osseous spinal axis with three dimensional computed tomography image appearences: dirty interface sign

Abstract

Purpose: We aimed to make a fast and accurate distinction of malignant and benign lesions in cases with predominantly solitary or multifocal involvement using latest technology software and hardware systems in computed tomography. Materials and Methods: 53 cases were included in the study. Primary (n = 42, 31 benign, 11 malignant) or metastatic (n = 11) tumors were detected at various locations in the bone structure of the cervical to coccygeal vertebrae in all cases. 3D CT images taken using the same system and biopsy or post-operative histopathology findings were available for all cases. Thin section images taken retrospectively from the archives were converted to 3D images using the same program and parameters, which were then recorded in the same window settings by two radiologists. Only 3D images were then analyzed to investigate the presence or absence of the dirty interface sign. Results: Dirty interface sign was present in 17 malignant lesions and absent in the remaining 5 lesions. As for benign lesions, the sign was present in only two lesions and the remaining 29 were negative for the sign. There was a high level of consistency between the two radiologists. In conclusion, malignant and benign lesions affecting the bone spinal axis were distinguished based on the presence or absence of the dirty interface sign with 77.3% sensitivity, 93.5% specificity and 86.8% accuracy. Conclusion: When evaluated with standard bone window views, 3D views can be used successfully for the distinction of malignant and benign bone tumors. At least, 3D views generated using low dose regimes in highly developed systems can be used with similar purpose to that of diffusion weighted MRI sequences that give roughly outlined but fast and accurate information about the lesion.