title: Innovations in imaging for chronic total occlusions: a glimpse into the future of angiography's blind-spot.
abstract: Chronic total occlusions (CTOs) are a subset of lesions that present a considerable burden to cardiovascular patients. There exists a strong clinical desire to improve non-surgical options for CTO revascularization. While several techniques, devices, and guide wires have been developed and refined for use in CTOs, the inability of angiography to adequately visualize occluded arterial segments makes interventions in this setting technically challenging. This review describes the current status of several invasive and non-invasive imaging techniques that may facilitate improved image guidance during CTO revascularization, with the goals of improving procedure safety and efficacy while reducing the time required to complete these interventions. Cardiac imaging also has important potential roles in selecting patients most likely to benefit from revascularization as well as pre-procedural planning, post-procedural assessment of revascularized segments and long-term outcomes studies. Modalities discussed include non-invasive techniques, such as CT(computed tomography) angiography and cardiac magnetic resonance imaging (MRI), as well as invasive techniques, such as intravascular ultrasound, optical coherence tomography, intravascular MRI, and conventional angiography. While some of these techniques have some evidence to support their use at present, others are at earlier stages of development. Strategies that combine imaging techniques with the use of interventional therapies may provide significant opportunities to improve results in CTO interventions and represent an active area of investigation.
authors.affiliation: Division of Cardiology, Schulich Heart Program, Sunnybrook Health Sciences Centre, Room A-253, 2075 Bayview Avenue, Toronto, Ontario M4N 3M5, Canada.
authors.forename: Brian K
authors.initials: BK
authors.lastname: Courtney
authors.forename: Nigel R
authors.initials: NR
authors.lastname: Munce
authors.forename: Kevan J
authors.initials: KJ
authors.lastname: Anderson
authors.forename: Amandeep S
authors.initials: AS
authors.lastname: Thind
authors.forename: General
authors.initials: G
authors.lastname: Leung
authors.forename: Perry E
authors.initials: PE
authors.lastname: Radau
authors.forename: F Stuart
authors.initials: FS
authors.lastname: Foster
authors.forename: I Alex
authors.initials: IA
authors.lastname: Vitkin
authors.forename: Robert S
authors.initials: RS
authors.lastname: Schwartz
authors.forename: Alexander J
authors.initials: AJ
authors.lastname: Dick
authors.forename: Graham A
authors.initials: GA
authors.lastname: Wright
authors.forename: Bradley H
authors.initials: BH
authors.lastname: Strauss
mesh_terms: D000818:Animals; D002908:Chronic Disease; D017023:Coronary Angiography / Q000379:methods; D003327:Coronary Disease / Q000175:diagnosis* / Q000628:therapy; D003952:Diagnostic Imaging / Q000379:methods*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods; D041623:Tomography, Optical Coherence / Q000379:methods; D014057:Tomography, X-Ray Computed / Q000379:methods; D018084:Ultrasonography, Interventional / Q000379:methods