Dual-energy CT myelography on detection of spontaneous spinal cerebrospinal fluid leaks: initial study

Abstract

Objective To assess the value of dual-energy computed tomography myelography (CTM) on detecting leaks of cerebrospinal fluid (CSF) in patients with spontaneous intracranial hypotension (SIH). Methods Six patients with SIH underwent spinal CTM on a 2nd generation dual-source CT with tube voltage set at 100 and 140 kVp(with tin filter). The virtual non-contrast (VNC) and iodine map images were calculated from dual-energy images. The average weighted (AW) CTM images were mixed from two kVp images with mix factor of 0. 5. Two radiologists evaluated CSF leak using two sets of images respectively: VNC + iodine map images and AW-CTM images. The results from two reading methods were compared. The level of CSF leaks along the nerve roots, C1-2 retrospinal CSF collections, epidural CSF collections and spinal epidural venous plexus were marked. The consensus about leak sites and CSF collections was made by two radiologists in the third session Kappa statistics were used to measure the agreement between the two methods. Results Forty-one leaks were detected using VNC + iodine map images. Forty-three leaks were detected on AW images. The agreement between two methods was excellent (Kappa =0. 997 ,P ＜0. 01). There were no differences in the detection of C1-2 retrospinal CSF collections (n = 2), epidural CSF collections(n = 3) or spinal epidural venous plexus (n = 1). VNC and iodine map images demonstrated superior visual effects than AW images. Conclusion Dual-energy CTM can be used to diagnose spontaneous spinal cerebrospinal fluid leaks in SIH patient. Key words: Tomography, X-ray computed; Myelography; Intracranial hypotension