We use the terms catheterization and cannulation interchangeably in the US. This is a bit of a misnomer, since these 2 processes are NOT identical; however, the end-result of each is the same: a hollow tube is introduced into a lumen or cavity, and this space is connected to the outside world.
Dictionary aside, if you know how to place a peripheral IV, you know how to perform these procedures. Here is my explanation of catheterization vs. cannulation as it relates to placing a peripheral IV, a procedure all med students are familiar with.
Vascular access is obtained through Cannulation with the Seldinger technique: A 22-16 gauge needle is used to pierce the skin and proximal vessel wall. Upon visualizing a flashback of blood, the hollow IV cannula is threaded over-the-needle, and guided directly into the lumen.
Catheterization begins when the tip of the plastic IV cannula enters the vessel lumen. This process involves blindly pushing the flexible hollow cannula forward, past the needle, and deeper into the lumen of the vessel. In contrast to cannulation, there is no trochar (needle) to create an artificial passage for the catheter, and there is no "guide wire" directing the catheter's journey.
Yeah the above definition is way off. You can "cannulate " something with any sort of tube or drain without using a needle. A catheter is generally fed over a guide wire which is first placed with aid of a needle.