Described herein is an implantable device configured to detect impedance characteristic of a tissue. In certain exemplary devices, the implantable device comprises (a) an ultrasonic transducer configured to emit an ultrasonic backscatter encoding information relating to an impedance characteristic of a tissue based on a modulated current flowing through the ultrasonic transducer; (b) an integrated circuit comprising (i) a variable frequency power supply electrically connected to a first electrode and a second electrode; (ii) a signal detector configured to detect an impedance, voltage, or current in a circuit comprising the variable frequency power supply, the first electrode, the second electrode, and the tissue; and (iii) a modulation circuit configured to modulate the current flowing through the ultrasonic transducer based on the detected impedance, voltage, or current; and the first electrode and the second electrode configured to be implanted into the tissue in electrical connection with each other through the tissue. Further described are systems including one or more implantable devices and an interrogator for operating the implantable device, methods of measuring impedance characteristic of a tissue in a subject, and methods of monitoring or characterizing a tissue in a subject.

A supra-aortic vessel access robotic control system includes a guidewire hub configured to adjust each of an axial position and a rotational position of a guidewire; a guide catheter hub configured to adjust a guide catheter in an axial direction; and a procedure catheter hub configured to adjust each of an axial position and a rotational position of a procedure catheter, and also to laterally deflect a distal deflection zone of the procedure catheter.

A method of performing a neurovascular procedure includes the steps of providing an access catheter having an access catheter hub; coupling the access catheter hub to a hub adapter, movably carried by a support table; driving the access catheter in response to movement of the hub adapter along the table until the access catheter is positioned to achieve supra-aortic vessel access; removing the access catheter and access catheter hub from the hub adapter; and coupling a procedure catheter hub having a procedure catheter to the hub adapter.

A method of performing a neurovascular procedure includes the steps of providing an access assembly comprising a guidewire, access catheter and guide catheter; coupling the access assembly to a robotic drive system; and driving the access assembly to achieve supra-aortic vessel access. The guide wire and the access catheter are decoupled from the access assembly. A procedure assembly includes at least a guidewire and a procedure catheter. The procedure assembly is coupled to the robotic drive system; and used to perform a neurovascular procedure.

A method enables analysis of (e.g. bioelectric) signals acquired by measurement. The method provides N signals U for an observation space and each has a time- and space-dependent signal characteristic U. Digitized signals for a time period T have M time points and define an M×N matrix with M tuples of N signal values each. Signal values acquired at time t form an N-tuple Ū.sub.t=(U.sub.1, . . . , U.sub.N).sub.t in a signal space. The method acquires all combinations of k tuples from the M tuples, and calculates distances between all tuples. Distance values are calculated and define edge lengths of a (k−1) simplex (SIM) with one simplex assigned to each combination of k time points. Quantity characteristics of the simplex (SIM) are encoded into color values (COL), and displays the colors in a combinatorial time lattice (CTL). Each lattice point (GP) is displayed with the color encoded for the assigned simplex.

A method enables analysis of (e.g. bioelectric) signals acquired by measurement. The method provides N signals U for an observation space and each has a time- and space-dependent signal characteristic U. Digitized signals for a time period T have M time points and define an M×N matrix with M tuples of N signal values each. Signal values acquired at time t form an N-tuple Ū.sub.t=(U.sub.1, . . . , U.sub.N).sub.t in a signal space. The method acquires all combinations of k tuples from the M tuples, and calculates distances between all tuples. Distance values are calculated and define edge lengths of a (k−1) simplex (SIM) with one simplex assigned to each combination of k time points. Quantity characteristics of the simplex (SIM) are encoded into color values (COL), and displays the colors in a combinatorial time lattice (CTL). Each lattice point (GP) is displayed with the color encoded for the assigned simplex.

Systems and methods for operating a biosensor are disclosed herein. In some embodiments, the biosensor is configured to access a user's interstitial fluid to determine the concentration of one or more analytes of interest. The method can include applying an excitation voltage to a working electrode of biosensor. The excitation voltage can be a time-varying waveform, such as a square waveform. The method can further include measuring a signal generated by the biosensor and analyzing the signal to determine one or more parameters of the biosensor and/or surrounding environment.

Systems and methods for operating a biosensor are disclosed herein. In some embodiments, the biosensor is configured to access a user's interstitial fluid to determine the concentration of one or more analytes of interest. The method can include applying an excitation voltage to a working electrode of biosensor. The excitation voltage can be a time-varying waveform, such as a square waveform. The method can further include measuring a signal generated by the biosensor and analyzing the signal to determine one or more parameters of the biosensor and/or surrounding environment.

A method includes receiving or generating (i) a volume map of at least a portion of a cavity of an organ of a body including a plurality of mapped locations, and (ii) ablation locations inside the cavity. The volume map is updated by removing a portion of the mapped locations, so that the ablation locations inside the cavity fall on a surface of the volume map. Using the updated volume map, a map of at least a portion of the cavity is generated, that includes the ablation locations located on a surface of the updated volume map. The map is displayed to a user.

A method includes receiving or generating (i) a volume map of at least a portion of a cavity of an organ of a body including a plurality of mapped locations, and (ii) ablation locations inside the cavity. The volume map is updated by removing a portion of the mapped locations, so that the ablation locations inside the cavity fall on a surface of the volume map. Using the updated volume map, a map of at least a portion of the cavity is generated, that includes the ablation locations located on a surface of the updated volume map. The map is displayed to a user.