Contrast collection pattern of lumbar epidurography in fluoroscopy and C- arm based flat panel volume CT

초록

Purpose: to evaluate contrast collection pattern of lumbar epidurography in fluoroscopy and C- arm based flat panel volume CT Material and method: Thirteen epidurographies were obtained in 12 patients via caudal approach (n =7), interlaminar approach (n= 2), transforaminal approach (n=3), and combined caudal and transforaminal approach (n=1) by both fluoroscopy and C- arm based flat panel volume CT (C-arm CT). The epidurographies were analyzed and compared between fluoroscopic image and C-arm CT by two spinal radiologists with consensus. Result: On lateral fluoroscopic images, 3/13 (23.07%) epidurographies showed contrast collection in anterior portion of central spinal canal whereas 10/13 (76.92%) epidurographies showed in posterior portion. On AP fluoroscopic images, 8/13 (61.93%) epidurographies showed contrast collection at central portion of central canal whereas 5/13 (38.46%) epidurographies showed in lateral portion. C-arm CT confirmed contrast collection in both anterior and posterior epidural space for 5/13 (38.46%) cases, only in anterior epidural space for 3/13 (23.07%) cases and only in posterior epidural space for 5/13 (38.46%) cases. In all but one case (12/13, 92.3%), contrast collection was observed in potential space between epidural fat and thecal sac, like coating the thecal sac. Six fluoroscopic epidurographies (6/13, 46.15%) were misdiagnosed contrast collection location compared with C-arm CT as a gold standard. The overall diagnostic accuracy of anteroposterior extension of contrast collection in fluoroscopic epidurographies was 61%. Conclusion: On fluoroscopy, Small amount of contrast collection in anterior or posterior epidural space can be missed. Most of the contrast collected in potential space between epidural fat and thecal sac, like coating the thecal sac.