Fusion of real-time US with CT images to guide sacroiliac joint injection in vitro and in vivo.

Abstract

To evaluate if image fusion, a technology matching real-time ultrasonography (US) and a previously obtained computed tomographic (CT) scan, is a feasible aid for sacroiliac (SI) joint injections in cadavers and patients. This study was approved by institutional review board, and written informed consent was obtained from each patient. In five human cadavers (10 joints) and seven consecutive patients (10 joints; four male, three female patients; mean age, 33.6 years; range, 22-44 years), SI joint injections were performed by using image fusion guidance technology. Registration errors were calculated automatically by the software and reported as mean registration error. In cadavers, needle placement was confirmed by means of CT, while in patients, a subjective rating of pain (score of 0-10) was recorded before and 3 months after injection. Procedure time was calculated. Matching of real-time US and CT images by image fusion software was reliable in all tests (mean registration error, 0.3 mm). In all cadavers, correct intraarticular needle positioning by using image fusion guidance was confirmed on CT scans. In patients, no intraprocedural complications were noted, and 3 months after injection pain score decreased (mean pain score before procedure, 8.05; after, 0.3). In patients, mean time for the whole procedure was 20.4 minutes (range, 17-22 minutes), with a mean duration of 15.4 minutes (range, 14-17 minutes) for image matching and 5 minutes (range, 3-7 minutes) for needle placement. Image fusion of real-time US and previously obtained CT scans is feasible to guide needle insertion into the SI joint.