title: Improved visualization of intracranial vessels with intraoperative coregistration of rotational digital subtraction angiography and intraoperative 3D ultrasound.
abstract: BACKGROUND
  Ultrasound can visualize and update the vessel status in real time during cerebral vascular surgery. We studied the depiction of parent vessels and aneurysms with a high-resolution 3D intraoperative ultrasound imaging system during aneurysm clipping using rotational digital subtraction angiography as a reference.
  
  
  METHODS
  We analyzed 3D intraoperative ultrasound in 39 patients with cerebral aneurysms to visualize the aneurysm intraoperatively and the nearby vascular tree before and after clipping. Simultaneous coregistration of preoperative subtraction angiography data with 3D intraoperative ultrasound was performed to verify the anatomical assignment.
  
  
  RESULTS
  Intraoperative ultrasound detected 35 of 43 aneurysms (81%) in 39 patients. Thirty-nine intraoperative ultrasound measurements were matched with rotational digital subtraction angiography and were successfully reconstructed during the procedure. In 7 patients, the aneurysm was partially visualized by 3D-ioUS or was not in field of view. Post-clipping intraoperative ultrasound was obtained in 26 and successfully reconstructed in 18 patients (69%) despite clip related artefacts. The overlap between 3D-ioUS aneurysm volume and preoperative rDSA aneurysm volume resulted in a mean accuracy of 0.71 (Dice coefficient).
  
  
  CONCLUSIONS
  Intraoperative coregistration of 3D intraoperative ultrasound data with preoperative rotational digital subtraction angiography is possible with high accuracy. It allows the immediate visualization of vessels beyond the microscopic field, as well as parallel assessment of blood velocity, aneurysm and vascular tree configuration. Although spatial resolution is lower than for standard angiography, the method provides an excellent vascular overview, advantageous interpretation of 3D-ioUS and immediate intraoperative feedback of the vascular status. A prerequisite for understanding vascular intraoperative ultrasound is image quality and a successful match with preoperative rotational digital subtraction angiography.
authors: Department of Neurosurgery, Dresden University of Technology, Carl Gustav Carus Faculty of Medicine, Dresden, Germany.
authors: Dino
authors: D
authors: Podlesek
authors: Institute of Biomedical Engineering, Dresden University of Technology, Faculty of Electrical Engineering and Information Technology, Dresden, Germany.
authors: Tobias
authors: T
authors: Meyer
authors: Institute of Biomedical Engineering, Dresden University of Technology, Faculty of Electrical Engineering and Information Technology, Dresden, Germany.
authors: Ute
authors: U
authors: Morgenstern
authors: Department of Neurosurgery, Dresden University of Technology, Carl Gustav Carus Faculty of Medicine, Dresden, Germany.
authors: Gabriele
authors: G
authors: Schackert
authors: Department of Neurosurgery, Dresden University of Technology, Carl Gustav Carus Faculty of Medicine, Dresden, Germany.
authors: Matthias
authors: M
authors: Kirsch
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015901:Angiography, Digital Subtraction / Q000379:methods*; D001921:Brain / Q000098:blood supply* / Q000000981:diagnostic imaging / Q000601:surgery; D002533:Cerebral Angiography / Q000379:methods; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging / Q000601:surgery*; D064795:Intraoperative Neurophysiological Monitoring / Q000379:methods*; D008297:Male; D008875:Middle Aged; D014463:Ultrasonography / Q000379:methods*