Optical coherence tomographic detection of cells and compositions

Provided herein are systems and methods for the detection of cells and/or compositions using optical coherence tomography. The systems and methods comprise a plurality of magnets for applying a plurality of distinct magnetic field strengths to the cells and/or compositions and a phase sensitive optical coherence tomographic imaging modality for detecting the cells and/or compositions while same are disposed in the presence of at least one of the plurality of distinct magnetic field strengths.