title: Optimized angiographic computed tomography with intravenous contrast injection: an alternative to conventional angiography in the follow-up of clipped aneurysms?
abstract: OBJECTIVE
  The purpose of this study was to evaluate the diagnostic accuracy of an optimized angiographic CT (ACT) program with intravenous contrast agent injection (ivACT) in the assessment of potential aneurysm remnants after neurosurgical clipping compared with conventional digital subtraction angiography (DSA).
  
  
  METHODS
  The authors report on 14 patients with 19 surgically clipped cerebral aneurysms who were scheduled to undergo angiographic follow-up. For each patient, the authors performed ivACT with dual rotational acquisition and conventional angiography including a 3D rotational run. The ivACT and 3D DSA data were reconstructed with different imaging modes, including a newly implemented subtraction mode with motion correction. Thereafter, the data sets were merged by the dual-volume technique, and freely rotatable 3D images were obtained for further analysis. Observed aneurysm remnants were electronically measured and classified for each modality by 2 experienced neuroradiologists.
  
  
  RESULTS
  Digital subtraction angiography and ivACT both provided high-quality images without motion artifacts. Artifact disturbances from the aneurysm clips led to a compromised, but still sufficient, image quality in 1 case. The ivACT assessed all aneurysm remnants as true-positive up to a minimal size of 2.6×2.4 mm in accordance with the DSA findings. There was a tendency for ivACT to overestimate the size of the aneurysm remnants. All cases without aneurysm remnants on DSA were scored correctly as true-negative by ivACT.
  
  
  CONCLUSIONS
  By using an optimized image acquisition protocol as well as enhanced postprocessing algorithms, the noninvasive ivACT seems to achieve results comparable to those of conventional angiography in the follow-up of clipped cerebral aneurysms. The authors have shown that ivACT can provide reliable diagnostic information about potential aneurysm remnants after neurosurgical clipping with high sensitivity and specificity, sufficient for clinical decision making, at least for aneurysms in the anterior circulation located distal to the internal carotid artery. These preliminary results may be a promising step to replace conventional angiography by a noninvasive imaging technique in selected cases after aneurysm clipping.
authors.affiliation: Department of Neuroradiology, University of Erlangen-Nuremberg, Erlangen, Germany. philipp.goelitz@uk-erlangen.de
authors.forename: Philipp
authors.initials: P
authors.lastname: Gölitz
authors.forename: Tobias
authors.initials: T
authors.lastname: Struffert
authors.forename: Oliver
authors.initials: O
authors.lastname: Ganslandt
authors.forename: Marc
authors.initials: M
authors.lastname: Saake
authors.forename: Hannes
authors.initials: H
authors.lastname: Lücking
authors.forename: Julie
authors.initials: J
authors.lastname: Rösch
authors.forename: Frauke
authors.initials: F
authors.lastname: Knossalla
authors.forename: Arnd
authors.initials: A
authors.lastname: Doerfler
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D015901:Angiography, Digital Subtraction; D020771:Anterior Cerebral Artery / Q000000981:diagnostic imaging / Q000601:surgery; D002533:Cerebral Angiography / Q000379:methods*; D003287:Contrast Media / Q000008:administration & dosage; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D007275:Injections, Intravenous; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging* / Q000601:surgery*; D007479:Iopamidol / Q000008:administration & dosage / Q000031:analogs & derivatives; D008297:Male; D008875:Middle Aged; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging / Q000601:surgery; D019635:Neurosurgical Procedures; D013345:Subarachnoid Hemorrhage / Q000000981:diagnostic imaging / Q000601:surgery; D013525:Surgical Instruments; D014057:Tomography, X-Ray Computed / Q000379:methods*; D016896:Treatment Outcome
chemical_list: D003287:Contrast Media; C057937:iomeprol; D007479:Iopamidol