A system comprising: means for accessing a memory to retrieve pre-operative image data for a patient; means for generating a three-dimensional patient-specific implicit model based on the pre-operative image data, wherein the patient-specific implicit model defines a geometry of an anatomical structure of the patient in a common three-dimensional coordinate system; means for storing the patient-specific implicit model in the memory; means for receiving tracking data from a tracking system representing a location of at least one sensor attached to an object within the patient in a tracking coordinate system of the tracking system, wherein the tracking data can be generated intraoperatively based on an output of the sensor and registered to the tracking coordinate system, wherein the output comprises a sensor signal provided in response to an electromagnetic field emitted by the tracking system from at least one location that is external to the patient; means for acquiring intraoperative image data for the patient, wherein the intraoperative image data represents the anatomical structure and at least one combination marker device that comprises an image marker detectable by said means for acquiring intraoperative image data and another marker detectable by the tracking system; means for computing an image space transformation to register the intraoperative image data comprising the at least one combination marker device to the common three-dimensional coordinate system; means for computing a registration matrix based on the tracking data and the intraoperative image data, such that the registration matrix provides a transformation from the tracking coordinate system of the tracking system to the common three-dimensional coordinate system; means for registering the tracking data in the common three-dimensional coordinate system in which the patient-specific implicit model is also registered by multiplying the tracking data by the computed registration matrix; and means for generating an output visualization based on the registration of the tracking data in the common three-dimensional coordinate system in which the patient-specific implicit model is also registered, the output visualization representing a location of the object relative to the geometry of the anatomical structure of the patient in the common three-dimensional coordinate system. means for accessing a memory to retrieve pre-operative image data for a patient; means for generating a three-dimensional patient-specific implicit model based on the pre-operative image data, wherein the patient-specific implicit model defines a geometry of an anatomical structure of the patient in a common three-dimensional coordinate system; means for storing the patient-specific implicit model in the memory; means for receiving tracking data from a tracking system representing a location of at least one sensor attached to an object within the patient in a tracking coordinate system of the tracking system, wherein the tracking data can be generated intraoperatively based on an output of the sensor and registered to the tracking coordinate system, wherein the output comprises a sensor signal provided in response to an electromagnetic field emitted by the tracking system from at least one location that is external to the patient; means for acquiring intraoperative image data for the patient, wherein the intraoperative image data represents the anatomical structure and at least one combination marker device that comprises an image marker detectable by said means for acquiring intraoperative image data and another marker detectable by the tracking system; means for computing an image space transformation to register the intraoperative image data comprising the at least one combination marker device to the common three-dimensional coordinate system; means for computing a registration matrix based on the tracking data and the intraoperative image data, such that the registration matrix provides a transformation from the tracking coordinate system of the tracking system to the common three-dimensional coordinate system; means for registering the tracking data in the common three-dimensional coordinate system in which the patient-specific implicit model is also registered by multiplying the tracking data by the computed registration matrix; and means for generating an output visualization based on the registration of the tracking data in the common three-dimensional coordinate system in which the patient-specific implicit model is also registered, the output visualization representing a location of the object relative to the geometry of the anatomical structure of the patient in the common three-dimensional coordinate system.