as many of the compounds listed above as thickening and suspending agents with algin being most preferred the amount of such agents will of course vary as those skilled in the art will recognize but generally will be employed in an amount of between about 5 and about 40 mmol l in some applications it may be helpful to incorporate gas forming agents into the contrast medium gas forming agents include sodium bicarbonate calcium carbonate aminomalonate and the like which will form gas for example upon introduction into the gastro intestinal tract such gas forming agents will serve to distend the gastrointestinal tract and create a form of 34 double contrast 34 between the gas and the low density microspheres kits useful for computed tomography imaging of the gastrointestinal region or other body cavities in accordance with the present invention comprise low density microspheres and a thickening or suspending agent in addition to conventional computed tomography imaging kit components such conventional computed tomography kit components will be readily apparent to those skilled in the art once armed with the present disclosure where imaging of the gastrointestinal region is contemplated such computed tomography kit components may include for example anti gas agents osmolality raising agents gastrointestinal transit agents and in some instances gas forming agents the computed tomography imaging.