Example embodiments associated with characterizing a sample using NMR fingerprinting are described. One example NMR apparatus includes an NMR logic that repetitively and variably samples a (k, t, E) space associated with an object to acquire a set of NMR signals that are associated with different points in the (k, t, E) space. Sampling is performed with t and/or E varying in a non-constant way. The NMR apparatus may also include a signal logic that produces an NMR signal evolution from the NMR signals and a characterization logic that characterizes a tissue in the object as a result of comparing acquired signals to reference signals. Example embodiments facilitate distinguishing diseased tissue from healthy tissue based on tissue component fractions identified using the NMR fingerprinting.

Example apparatus and methods improve magnetic resonance fingerprinting (MRF) by performing MRF with optimized spatial encoding, parallel imaging, and utilization of field inhomogeneities. Multi-echo radial trajectories and spiral trajectories may acquire data according to sampling schemes based on models of charge distribution on a sphere. Non-uniform sampling schemes may account for differences in detector coil performance. Field inhomogeneities provide spatial information that enhances the spatial separation of an MRF signal and facilitates unaliasing pixels. The field inhomogeneity may be manipulated. An MRF pulse sequence may include frequency selective RF pulses that are determined by the field inhomogeneities. Inhomogeneities combined with selective RF pulses result in higher acquisition efficiency.

A bone harvesting device may facilitate the removal of bone from a surgical site, for therapeutic or diagnostic purposes. The device may have a harvester tube, a harvester tube fitting, and a slide hammer. The harvester tube may have a proximal end, a distal end, and a hollow portion that can receive a sample of the bone and/or a plunger with a point that breaches cortical bone. The harvester tube fitting may be coupled to the proximal end of the harvester tube, and may receive impact to urge the distal end of the harvester tube into the bone. The slide hammer may translate along the harvester tube and impact the harvester tube fitting to urge removal of the proximal end from the bone. Complementary attachment features on the harvester tube fitting and the slide hammer may detachably couple the slide hammer to the harvester tube fitting.

Example embodiments associated with NMR fingerprinting are described. One example NMR apparatus includes an NMR logic that repetitively and variably samples a (k, t, E) space associated with an object to acquire a set of NMR signals that are associated with different points in the (k, t, E) space. Sampling is performed with t and/or E varying in a non-constant way. Sampling is performed in response to a fast imaging with steady state free precession (MRF-FISP) pulse sequence having an unbalanced gradient that dephases transverse magnetization. The NMR apparatus may also include a signal logic that produces an NMR signal evolution from the NMR signals, and a characterization logic that characterizes a resonant species in the object as a result of comparing acquired signals to reference signals. The unbalanced gradient in the MRF-FISP pulse sequence reduces sensitivity to B0 in homogeneity.

In an EPI acquisition sequence for magnetic resonance signals k-space is scanned along sets of lines in k-space along opposite propagation directions, e.g. odd and even lines in k-space. Phase errors that occur due to the opposite propagation directions are corrected for in a SENSE-type parallel imaging reconstruction. The phase error distribution in image space may be initially estimated, calculated form the phase difference between images reconstructed from magnetic resonance signals acquired from the respective sets of k-space lines, or from an earlier dynamic.

Example embodiments associated with characterizing a sample using NMR fingerprinting are described. One example NMR apparatus includes an NMR logic that repetitively and variably samples a (k, t, E) space associated with an object to acquire a set of NMR signals that are associated with different points in the (k, t, E) space. Sampling is performed with t and/or E varying in a non-constant way. The NMR apparatus may also include a signal logic that produces an NMR signal evolution from the NMR signals and a characterization logic that characterizes a tissue in the object as a result of comparing acquired signals to reference signals. Example embodiments facilitate distinguishing diseased tissue from healthy tissue based on tissue component fractions identified using the NMR fingerprinting.

A method for securing a repair, such as a rotator cuff repair and includes an anchor placed within a hole formed in bone and a cannulated screw inserted into the hole after the anchor has been inserted to effectuate a firm and secure connection of tissue to bone, particularly when the quality of the bone does not permit optimal fixation. The method allows superior tissue fixation to bone with the ease of knotless suture anchor application.

Example embodiments associated with characterizing a sample using NMR fingerprinting are described. One example NMR apparatus includes an NMR logic that repetitively and variably samples a (k, t, E) space associated with an object to acquire a set of NMR signals that are associated with different points in the (k, t, E) space. Sampling is performed with t and/or E varying in a non-constant way. The NMR apparatus may also include a signal logic that produces an NMR signal evolution from the NMR signals and a characterization logic that characterizes a tissue in the object as a result of comparing acquired signals to reference signals. Example embodiments facilitate distinguishing diseased tissue from healthy tissue based on tissue component fractions identified using the NMR fingerprinting.

Example apparatus and methods perform magnetic resonance fingerprinting (MRF) for arterial spin labeling (ASL) based parameter quantification. ASL with MRF produces a nuclear magnetic resonance signal time course from which simultaneous quantification of ASL perfusion-related parameters can be achieved. The parameters may include cerebral blood flow, transit time, T1, or other parameters. The quantification uses values from a dictionary of signal time courses that were generated or augmented using Bloch simulation, knowledge of the sequence, or previous observations. The dictionary may account for inflow or outflow of labeled spins and may model arterial input. An ASL-MRF pulse sequence may differ from conventional pulse sequences. For example, an ASL-MRF pulse sequence may include non-uniform control pulses, non-uniform label pulses, non-uniform post labeling delay time, non-uniform background suppression pulses, non-uniform acquisition repetition time, or non-uniform acquisition flip angle.

In an EPI acquisition sequence for magnetic resonance signals k-space is scanned along sets of lines in k-space along opposite propagation directions, e.g. odd and even lines in k-space. Phase errors that occur due to the opposite propagation directions are corrected for in a SENSE-type parallel imaging reconstruction. The phase error distribution in image space may be initially estimated, calculated form the phase difference between images reconstructed from magnetic resonance signals acquired from the respective sets of k-space lines, or from an earlier dynamic.