Abstract: A guidewire having a shaft comprising an optical fiber and an optical handle through which direct visualization is provided. The guidewire may be inserted alone through a passageway of a patient to visualize the internal anatomy of the patient such as inside a passageway or the inside of an organ. The guidewire may also be inserted through a catheter or endoscope to aid in navigation to the intended location. Additionally, the guidewire may be inserted into other catheters, which are then tracked over the guidewire to the subject area The guidewire comprises a removable optical handle which permits catheter exchanges over its proximal end when made in an exchange length configuration or is used with rapid-exchange catheters. The guidewire may also comprise a light fiber bundle along with the optical fiber, together surrounded by a jacket to form the elongate guidewire.