CTによる上顎洞壁肥厚像に関する実験的研究

概要

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In our previous report, we investigated several factors which cause apparant thickening of the walls of maxillary sinus. We confirmed, however, that the major factor for the sinal wall thickening is the artifact of CT. In present study, we report the results obtained by phantom models of isolated maxillary bone and egg shell. As the substance corresponding to the soft tisse density, solutions of CaCl2 in various concentrations were used. In the maxillary bone studies, the thickness of the anterior sinus wall by CT was larger than the actual value even though only the air was contained. When solutions of CaCl2 were contained and in touch with the anterior wall, the thickness by CT was larger than that of containing air. In the egg shell studies, the increase in thickness by CT correlated to the increase in percentage of solutions. The above results indicate that the apparent increased thickness of the sinal walls by CT is largely the artifact by CT and is dependent upon the soft tissue density or CT value (X-ray attenuation coefficient) of substances in touch with the sinal walls.In CT images obtained by clinical cases, the increased thickness of the sinal walls, in sinuses filled with soft tissue density, is more apparent than real.