Minimally invasive access channels into bodily regions

The present invention discloses access devices and methods to create an access channel for introduction of one or more working devices into an anatomical region. The access channel is created using a visualization modality that is later removed before inserting one or more working devices through the access channel. This allows the methods and devices of the present invention to be used even in small sized natural or surgically created insertion tracts leading to the anatomical region. The access channel can be made of a device such as a sheath, a guidewire, and an elongate device comprising a lumen. Examples of visualization modalities are endoscopes and body insertable ultrasound imaging devices. The working devices can be used to perform a variety of diagnostic, therapeutic, or preventive procedures. Endometrial ablation devices and procedures have been used as an example to describe various aspects of the present invention.