Radiology - the photography of the interior

What diagnoses can be made on the basis of a CT scan?

Computed tomography allows a large number of diagnoses to be made in a very short time. The disadvantage is that this method works with X-rays. It is therefore mainly used when time is of the essence. For example, after an accident, if an acute injury is suspected, in the event of an acute deterioration of the patient, for example due to an infection/inflammation, or in the case of a suspected tumour, a CT scan is appropriate.

A CT scan is always useful if the diagnosis needs to be made as quickly as possible so that treatment can be given quickly to prevent further damage.

My wife is suspected of having pneumonia. Why is a CT scan carried out?

As a rule, a normal X-ray of the lungs is sufficient for pneumonia. However, it can sometimes be difficult to see the inflammatory changes in the lungs caused by germs. In such cases, a computerised tomography scan is performed. In particular, atypical bacteria or viruses, which only cause very subtle changes in the tissue but nevertheless cause severe symptoms of the disease, can only be recognised in high-resolution tomograms.

There are also diseases that can simulate pneumonia. In order to prove that it is pneumonia, a CT scan may be required in addition to blood or mucus tests to ensure that patients are treated with the right medication and that no more serious illness is overlooked.

What is the most interesting thing you have ever found out thanks to a CT scan?

I experienced a very interesting case as a young senior consultant. I had a patient who had to be repeatedly hospitalised in another hospital due to severe liver inflammation. This was accompanied by chills. Although it subsided after antibiotics, it kept coming back and also showed signs of septicaemia. At the time, it was assumed to be an inflammation of the bile ducts, as nothing indicative could be found in the imaging. I was working at a university hospital at the time and had a computerised tomography scan. In this examination I also found no typical changes in the area of the liver or the bile ducts.

However, there was a bright "dot" about two millimetres in size in the centre of the liver, which I was unable to classify more precisely. No anatomical structure that I knew of matched it. Through some image post-processing, I found out that although this dot was only two millimetres in diameter, it was about two centimetres long and looked like a line. After the three-dimensional reconstruction on the computer, I realised that it was in the immediate vicinity of the first section of the intestine after the stomach, the so-called duodenum.

I then boldly postulated that this could be a swallowed foreign body - such as a toothpick. My thought was that it could have pierced the intestinal wall and travelled to the liver. A foreign body that doesn't belong there and always leads to inflammation in the liver. It was risky to make this suspected diagnosis, especially as a young senior consultant. After all, my diagnosis would lead to a patient having to undergo a dangerous liver operation. What if I was wrong?

The patient was indeed operated on. It turned out to be a small bone from a chicken wing. We all know it, that small but sharp, pointed bone. Part of it was actually lodged in the liver, where it kept causing inflammation.

Afterwards, the patient confirmed that he likes to chew on bones and occasionally swallows them. Although it was ultimately not the suspected toothpick but a bone, it was a foreign body that would have continued to cause inflammation in the liver if it had not been removed. In this respect, the interpretation of the two-millimetre dot in the CT scan was of decisive importance for the patient's recovery.

What diagnoses can be made on the basis of an MRI?

The MRI examination has a very good natural soft tissue contrast. This means that different types of tissue can be differentiated from each other, usually without additional contrast agents. This is why it is mainly used when you want to see changes within tissue. This is the case with joints, for example, when you want to distinguish muscles from tendons, cartilage and bones. It is also very good at differentiating between brain parenchyma, which is made up of different types of tissue. MRI is also frequently used to visualise inflammatory changes or fine fractures. In the case of inflammation or a bone fracture, there is always a little more fluid in this area as the body itself tries to heal. It sends certain substances to this area. This increased fluid can be visualised so that inflammation that remains undetected in other examinations can be detected.

I have claustrophobia. Can I still have an MRI scan?

An MRI scan is usually open at the front and back. You will feel cramped in the examination tube, which is quite normal. If someone suffers from claustrophobia, this can be a nightmare. If the MRI is absolutely necessary, we do everything we can to make the examination possible for this patient.

Sometimes it is enough to close your eyes before you are wheeled in. That way, the confinement is not even noticed. A relative or best friend can of course come into the examination room with you and hold your hand to reassure you. This closeness often conveys a sense of security. If this does not work, we can also calm the patient with medication or put him or her to sleep completely so that the time in the tube is not noticed. It is important that we know this in advance so that we can plan accordingly.

Why am I not allowed to eat before an MRI?

That depends on the examination. Eating or drinking causes changes in the body. Depending on what we want to find out, it is important to prevent food intake from visually affecting the area we want to examine. For example, if we want to visualise the liver with the gallbladder and pancreas, it is important that the gallbladder, which empties with food intake, is clearly visible. If this is not observed, it will collapse and a possible gallbladder stone may not be found. Intestinal motility is also increased after eating. This is quite normal as it has to work. However, this interferes with imaging because the intestinal loops are then blurred or out of focus and any malignant changes cannot be seen.

In addition, there are certain substances in food that increase the heart rate, for example. So when we carry out a heart examination, no coffee or tea should be drunk beforehand, as both drinks contain substances that stimulate the circulation.