The present invention provides scanning mechanisms for imaging probes for imaging mammalian tissues and structures using high resolution imaging, including high frequency ultrasound and/or optical coherence tomography. The imaging probes include adjustable rotational drive mechanism for imparting rotational motion to an imaging assembly containing either optical or ultrasound transducers which emit energy into the surrounding area. The imaging assembly includes a scanning mechanism including a movable member configured to deliver the energy beam along a path out of said elongate hollow shaft at a variable angle with respect to said longitudinal axis to give forward and side viewing capability of the imaging assembly. The movable member is mounted in such a way that the variable angle is a function of the angular velocity of the imaging assembly.