if you think of your ultrasonic sensor as 1 pixel in a video camera but you can not see much with a single pixel, so you need more or you move the pixel around and build up a pitcher of your surroundings 1 pixel at a time .
mount the ultrasonic sensor on to a tilt and pan device of your choice
write a program to pan the sensor 1 step at a time and for every step take an ultrasonic sensor measurement . send that measurement to a display . you could use color or gray scail to represent the distance values for each pixel . line the pixels up and when you get to the end of the row tilt up or down 1 and scan back the other way
as you go threw the full range of movement you see a pitcher of some sort build up 1 row at a time it may be a bit fuzzy and slow but it can be done
as for ultrasonography , i have know idea
there is some interesting maths for visualizing it on screen,
Someone posted this on the product page for this sensor https://www.sparkfun.com/products/8958
Theyre using an IR distance sensor but the idea is similar. That being said, I think youre going to have a hard time with this project. The reason being, is that the beam width of most ultrasonic sensors is fairly wide. This is good for detecting if there are any objects in front of the sensor, but will result in a pretty low resoution image. It's not impossible but at best you will get a very low resolution image. A sensor with a narrower beam pattern would be ideal.