MRI scanner
MRA

X rays

We have with this modern technology several ways of getting images of what our body looks like on the inside.Some of them require some radiation and some of them work with sound, others again with magnetic fields. If you are tested for high blood pressure you may encounter the following imaging techniques.

Ultrasound

This is a well know technique, also because most women have had ultrasounds when they were pregnant and as you know it can give you an amazing picture of the inside of the body, especially the baby. When we are looking for causes of high bloodpressure, we use the ultrasound mainly to tell us something about the kidneys. The kidneys are nmormally two bean-shaped organs, with a length of about 12 cm each, lying high up in our backs, the top often just hidden under the last rib. The ultrasound, as a test that causes no pain or damage, will gives us a good impression about the size of the kidneys, whether there are any stones, and whether the urine flow is normal. If one of the kidneys is blocked, this is very obvious. For high blood pressure, we look mainly at the size of the kidneys. If one, or even both of the kidneys are very small, this could be a clue that the big artery (blood vessel going to the kidney) is narrowed or even blocked and we may need to do something to repair this (see Renal Artery Stenosis).

CT scan

A CT scan (Computerized Tomography scan), gives us an image of our internal organ, by making slices through our body that are millimeters of a centimetre thick. It gives a very real and very detailed impression of all the internal organ. In the past we injected patients with a dye to see how this distributed in the kidneys and the large blood vessels. the CT scan uses radiation and the technique has now often been replaced by the MRA scan

MRA scan

The apparatus used is a so-called MRI scanner (Magnetic Resonance Scanner). In the tunnel where the patient passes through a magnetic field is established, a little bit like a microwave, but not generating any heat and all the molecules in our body react different to that (there is 'resonance'). it gives us even a more detailed impression of our inner organs than the CT scanner and such without radioactivity! A dye is usually injected in one of the arms, that quickly finds its way to the kidney blood vessels and we get a very detailed image of these bloodbvessels and potential narrowing or obstruction of them. The imagine, once made, can even be rotated and we get a beautiful 3-dimensional image of how the bloodsupply of our kidneys is orhganised.

Renal angiography

This method is a little outdated now that we have the MRA scanner. Still, for difficult cases it can be very helpful. A catheter (very thin plastic tube) is inserted in one of the groins and slowly advanced through the bloodvessel to the kidneys. there some dye is released thorugh the catheter and the bloodvessels become very visible. the disadvantage is that there is a need for a large series of X rauys and obviously the radioactive exposure can be an issue for younger people.