title: Accuracy considerations in image-guided cardiac interventions: experience and lessons learned.
abstract: BACKGROUND
  Medical imaging and its application in interventional guidance has revolutionized the development of minimally invasive surgical procedures leading to reduced patient trauma, fewer risks, and shorter recovery times. However, a frequently posed question with regard to an image guidance system is "how accurate is it?" On one hand, the accuracy challenge can be posed in terms of the tolerable clinical error associated with the procedure; on the other hand, accuracy is bound by the limitations of the system's components, including modeling, patient registration, and surgical instrument tracking, all of which ultimately impact the overall targeting capabilities of the system.
  
  
  METHODS
  While these processes are not unique to any interventional specialty, this paper discusses them in the context of two different cardiac image guidance platforms: a model-enhanced ultrasound platform for intracardiac interventions and a prototype system for advanced visualization in image-guided cardiac ablation therapy.
  
  
  RESULTS
  Pre-operative modeling techniques involving manual, semi-automatic and registration-based segmentation are discussed. The performance and limitations of clinically feasible approaches for patient registration evaluated both in the laboratory and in the operating room are presented. Our experience with two different magnetic tracking systems for instrument and ultrasound transducer localization is reported. Ultimately, the overall accuracy of the systems is discussed based on both in vitro and preliminary in vivo experience.
  
  
  CONCLUSIONS
  While clinical accuracy is specific to a particular patient and procedure and vastly dependent on the surgeon's experience, the system's engineering limitations are critical to determine whether the clinical requirements can be met.
authors.affiliation: Biomedical Imaging Resource, Mayo Clinic, Rochester, MN, USA. linte.cristian@mayo.edu
authors.forename: Cristian A
authors.initials: CA
authors.lastname: Linte
authors.forename: Pencilla
authors.initials: P
authors.lastname: Lang
authors.forename: Maryam E
authors.initials: ME
authors.lastname: Rettmann
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Cho
authors.forename: David R
authors.initials: DR
authors.lastname: Holmes
authors.forename: Richard A
authors.initials: RA
authors.lastname: Robb
authors.forename: Terry M
authors.initials: TM
authors.lastname: Peters
mesh_terms: D000818:Animals; D006348:Cardiac Surgical Procedures / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D006331:Heart Diseases / Q000601:surgery*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D053783:Magnetic Resonance Imaging, Interventional / Q000295:instrumentation; D008280:Magnetics; D019060:Minimally Invasive Surgical Procedures; D015642:Radiology, Interventional / Q000295:instrumentation; D015203:Reproducibility of Results; D025321:Surgery, Computer-Assisted / Q000295:instrumentation* / Q000379:methods; D018084:Ultrasonography, Interventional / Q000295:instrumentation