Abstract: Magnetic resonance imaging contrast agents that include a plurality of gas vesicles configured to associate with a noble gas are provided. Also provided are magnetic resonance imaging methods that include administering to a subject a contrast agent that includes a plurality of gas vesicles, obtaining a magnetic resonance data of a target site of interest, and analyzing the data to produce a magnetic resonance image of the target site. The subject contrast agents and methods find use in magnetic resonance imaging applications.

Abstract: This disclosure provides systems, methods, and apparatus related to depth well logging. In one aspect, an apparatus includes a radio frequency (RF) coil and a magnetic field sensing device. The apparatus is configured to be positioned in a first magnetic field. The first magnetic field polarizes nuclear spins of species in a detection region proximate the apparatus. The apparatus generates a second magnetic field for a time period with the RF coil to excite the nuclear spins of the species in the detection region. Then, the apparatus measures electromagnetic radiation, using the magnetic field sensing device, generated by the species as a result of the excitation of the nuclear spins.