1. A method for determining the presence of content in-vivo, the method comprising: capturing a plurality of image frames of a gastrointestinal tract using an imager; identifying, using a processor, content in at least one image frame, said content including any fluid, solid, liquid, gas, particle, feces, rough reduces, fluid bile, or any substance that is not a permanent or stagnant substance within a body lumen; calculating, using a processor, a percentage of said content in the at least one image frame which was identified to include said content; calculating, using a processor, a cleanliness index for the plurality of image frames based on an average of said percentage of content derived from a subset of the plurality of image frames; and based on the cleanliness index, determining, using a processor, success of a preparatory procedure for cleaning the gastrointestinal tract.