経皮的椎体形成術における二酸化炭素 (CO2) を用いた椎体静脈造影の基礎的検討

Purpose: In percutaneous vertebroplasty (PVP), intraosseous venography is performed using water-soluble ionic iodinated contrast media (iodine contrast media) before injecting bone cement. However, because of contrast medium remaining in the fractured cleft, we experienced the persistence of intravertebral opacification that obscured visualization of the cement under X-ray fluoroscopy. To solve this problem, we examined carbon dioxide (CO2) as a contrast medium. Methods: We measured the contrast of iodine contrast media and CO2 and performed a subjective assessment of imaging by enforcing intraosseous venography by changing the tube voltage and image intensifier (I.I.) entrance dose in a bone sample of a cadaver using iodine contrast media and CO2. In vivo study, we performed a subjective assessment of images obtained by intraosseous venography using CO2 under two kinds of X-ray views. Results: We determined that the contrast of CO2 is 1/6-1/7.5 that of iodine contrast media, and that CO2 fluctuates less in its contrast value with changes in tube voltage. In our assessment of the image of the bone sample, CO2 performed worse that iodine contrast media. However, if the I.I. entrance dose is kept above 2.5 μGy/F, CO2 is considered to be of clinical use. In the clinical image assessment, the best conditions were an image collection rate of 7.5 F/S and matrix of 1024×1024. Conclusions: CO2 did not cause any obstacles when we injected bone cement, and its I.I. entrance dose, image collection rate, and matrix size indicate that it can be used for intraosseous venography.