Fig. 1.

(a) Photo of the compact multimodal flap perfusion-monitoring device that evaluates complimentary perfusion parameters, including blood flow, tissue oxygenation, and hemoglobin concentration, by combining two-channel DCS and one-channel DRS—due to its compact footprint, multiple devices can be stacked in a constrained space for multisite flap monitoring. (b) Block diagram of the device shows the major components of each modality—the components have been carefully selected to achieve miniaturization while retaining comparable performance to the conventional DCS construction (long coherence LD, hardware correlator, and single-photon counting detector) and DRS (halogen lamp + intensified charged-couple device). (c) Implantable DCS probes are designed in two ways: using angle-polished fibers with final entry angle of 60 deg (left) and using a right-angle prim potted in an epoxy (right).