Embodiments herein provide an ultrahigh sensitive optical microangiography (OMAG) system that provides high sensitivity to slow flow information, such as that found in blood flow in capillaries, while also providing a relatively low data acquisition time. The system performs a plurality of fast scans (i.e., B-scans) on a fast scan axis, where each fast scan includes a plurality of A-scans. At the same time, the system performs a slow scan (i.e., C-scan), on a slow scan axis, where the slow scan includes the plurality of fast scans. A detector receives the spectral interference signal from the sample to produce a three dimensional (3D) data set. An imaging algorithm is then applied to the 3D data set in the slow scan axis to produce at least one image of the sample. In some embodiments, the imaging algorithm may separate flow information from structural information of the sample.