Abstract
Two types of rib primary bone tumor are observed, osteolytic and osteosclerotic. The osteolytic type destroys bone as it grows and has CT values lower than those of the liver and other organs. The osteosclerotic type protrudes from the bone surface, and because it has CT values similar to those of bone areas, borders between tumor and skeleton are difficult to distinguish, making separating the two areas difficult, and therefore presenting challenges in quantifying volumetric measurement and other operations. In this study, osteolytic/osteosclerotic evaluation and detection of tumors were conducted, and volumetric measurement conducted by means of left-right skeleton comparison. Volumetric measurement employing left-right volume skeleton comparison was used for osteosclerotic tumors; for osteolytic tumors, a tumor extraction technique is proposed that exhibits high precision superior to that of the conventional area expansion method, which accomplished through use of a discriminator that employs a support vector machine (SVM). Rib left-right symmetry was investigated using healthy cases. Osteolytic/osteosclerotic evaluation and detection of tumors and volumetric measurement were conducted using four osteolytic tumor cases and one osteosclerotic tumor case. Volumetric differences between corresponding left and right healthy ribs were kept within 10%, enabling acquisition of clear volumetric differences with symptomatic cases. Additionally, bone tumor volumes could be measured with almost no error by obtaining corresponding rib differentials, thereby demonstrating that tumor detection can be performed.
