Role of digital subtraction fluoroscopic imaging in detecting intravascular injections

Complications of unintended intravascular penetration and subsequent injection of local anesthetics and/or other drugs occasionally are devastating. Multiple reports have related to unrecognized intravascular placement of the needle. The generally accepted technique during interventional techniques is intermittent fluoroscopy. In fact, this may miss vascular uptake due to rapid washout. Thus, digital subtraction, the commonly accepted standard for documenting angiography and venography, may be a useful tool for documentation of and/or avoidance of intravascular placement of the needle and subsequent injections with interventional techniques. This case report involves description of digital subtraction to enhance visualization of contrast distribution during injection. Three series of images are included from atlanto-occipital joint, caudal epidural catheterization, and a cervical transforaminal injection. The case reports demonstrate that digital subtraction fluoroscopic imaging is superior to intermittent or live fluoroscopy in detecting intravascular injections with interventional techniques.