title: Cardiac CT With Delayed Enhancement in the Characterization of Ventricular Tachycardia Structural Substrate: Relationship Between CT-Segmented Scar and Electro-Anatomic Mapping.
abstract: This study sought to compare myocardial scars depicted by computed tomography (CT) with electrical features from electro-anatomic mapping (EAM), assessing the potential role of CT integration in ventricular tachycardia (VT) and radiofrequency catheter ablation (RFCA) procedures.
  
  
  
  Imaging-based characterization of VT myocardial substrate is required to plan EAM and, potentially, to guide RFCA.
  
  
  
  Forty-two consecutive patients, 35 of whom had implantable cardioverter-defibrillator, all referred for VT RFCA, underwent pre-procedural CT including an angiographic and a 10-min delayed-enhancement scan. Segmental comparison between scars segmented from CT and low voltages (bipolar voltages <1.5 mV; unipolar voltages <8 mV), late potentials, and RF ablation points on EAM, was carried out. In a subset of 16 consecutive patients, a further point-by-point analysis was performed: a CT-derived 3-dimensional structure including heart anatomy and myocardial scars was integrated with EAM for quantitative comparison.
  
  
  
  CT scans identified scars in 39 patients and defined left ventricular wall involvement and mural distribution. Overall segmental concordance between CT and EAM was good (κ = 0.536) despite the presence of implantable cardioverter-defibrillator, scar etiologies, and mural distribution. CT identified segments characterized by low voltages with good sensitivity (76%), good specificity (86%), and very high negative predictive value (95%). Late potentials and RF ablation points fell on scarred segments identified from CT in 79% and 81% of cases, respectively. Point-by-point quantitative comparison revealed good correlation between the average area of scar detected at CT and at bipolar mapping (CT = 4,901 mm(2), bipolar voltages-EAM = 4,070 mm(2); R = 0.78; p < 0.0001). In this study, 70% and 84% of low-amplitude bipolar points were mapped at a maximum distance of 5 mm and 10 mm from CT-segmented scar, respectively.
  
  
  
  CT with delayed-enhancement provides a 3-dimensional characterization of VT scar substrate together with a detailed anatomic model of the heart. This information may offer assistance to plan EAM and RFCA procedures and is potentially suitable for EAM-imaging integration.
authors.affiliation: Unit of Clinical Research in Radiology, Experimental Imaging Center, IRCCS San Raffaele Scientific Institute, Milan, Italy; Università Vita-Salute San Raffaele, Milan, Italy. Electronic address: esposito.antonio@hsr.it.
authors.forename: Antonio
authors.initials: A
authors.lastname: Esposito
authors.affiliation: Unit of Clinical Research in Radiology, Experimental Imaging Center, IRCCS San Raffaele Scientific Institute, Milan, Italy; Università Vita-Salute San Raffaele, Milan, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Palmisano
authors.affiliation: Images Post-Processing and Analysis, Experimental Imaging Center, IRCCS San Raffaele Scientific Institute, Milan, Italy.
authors.forename: Sofia
authors.initials: S
authors.lastname: Antunes
authors.affiliation: Arrhythmia Unit and Electrophysiology Laboratories, IRCCS San Raffaele Scientific Institute, Milan, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Maccabelli
authors.affiliation: Unit of Clinical Research in Radiology, Experimental Imaging Center, IRCCS San Raffaele Scientific Institute, Milan, Italy; Università Vita-Salute San Raffaele, Milan, Italy.
authors.forename: Caterina
authors.initials: C
authors.lastname: Colantoni
authors.affiliation: University Centre of Statistics in the Biomedical Sciences, Vita-Salute San Raffaele University, Milan, Italy.
authors.forename: Paola Maria Vittoria
authors.initials: PMV
authors.lastname: Rancoita
authors.affiliation: Arrhythmia Unit and Electrophysiology Laboratories, IRCCS San Raffaele Scientific Institute, Milan, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Baratto
authors.affiliation: University Centre of Statistics in the Biomedical Sciences, Vita-Salute San Raffaele University, Milan, Italy.
authors.forename: Clelia
authors.initials: C
authors.lastname: Di Serio
authors.affiliation: Institute of Molecular Bioimaging and Physiology, Consiglio Nazionale delle Ricerche, Segrate, Province of Milan, Italy.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Rizzo
authors.affiliation: Unit of Clinical Research in Radiology, Experimental Imaging Center, IRCCS San Raffaele Scientific Institute, Milan, Italy; Università Vita-Salute San Raffaele, Milan, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: De Cobelli
authors.affiliation: Arrhythmia Unit and Electrophysiology Laboratories, IRCCS San Raffaele Scientific Institute, Milan, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Della Bella
authors.affiliation: Unit of Clinical Research in Radiology, Experimental Imaging Center, IRCCS San Raffaele Scientific Institute, Milan, Italy; Università Vita-Salute San Raffaele, Milan, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Del Maschio
mesh_terms: D000200:Action Potentials; D000368:Aged; D009202:Cardiomyopathies / Q000150:complications / Q000000981:diagnostic imaging* / Q000503:physiopathology; D017115:Catheter Ablation; D002921:Cicatrix / Q000150:complications / Q000000981:diagnostic imaging* / Q000503:physiopathology; D000072226:Computed Tomography Angiography; D003287:Contrast Media / Q000008:administration & dosage; D017147:Defibrillators, Implantable; D004554:Electric Countershock / Q000295:instrumentation; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006339:Heart Rate; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography; D009206:Myocardium / Q000473:pathology*; D011237:Predictive Value of Tests; D011857:Radiographic Image Interpretation, Computer-Assisted; D017180:Tachycardia, Ventricular / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology / Q000601:surgery
chemical_list: D003287:Contrast Media
keywords: cardiac computed tomography; computed tomography delayed enhancement; electro-anatomic mapping; radiofrequency catheter ablation; ventricular tachycardia