Inside the black box

X-ray technician: ''The bad news is you've swallowed a bunch of those tiny green plastic soldiers. The good news is they all ended up in your GI tract.''!

Relax - the black box I’ll be talking about is not a coffin. This is just a term that researchers use to describe a system with an unknown design. We can get an idea about its structure only from external signs. The human body was such a black box for a long time: its content could be observed only during an autopsy or surgery, at which point information about it, as you may realize, was not particularly useful.

A first look into the black box

Sure, doctors always dreamed of peeking into this black box to diagnose illnesses before it was too late. These dreams materialized by the end of the 19th century when the now famous Konrad Roentgen, the German physicist, discovered the mysterious X-rays that penetrated through the human body, making it possible to visualize bones and, partly, internal organs.

Röntgen’s discovery was groundbreaking. For the first time, physicians had a non-invasive method to observe the internal condition of their patients. (image source: https://suindependent.com/)

These rays have since become one of the most popular diagnostic tools. X-ray imaging is a convenient, simple, and inexpensive method. It can easily display bone fractures, dark patches in the lungs, or a gut perforation. But that’s pretty much it: a multitude of problems remain invisible. Moreover, an X-ray image is just a two-dimensional shadow of a three-dimensional object. One needs a lot of imagination to understand what is really happening inside the body from those overlapping shadows of varying density.

Computer imaging

Later in the 20th century, radiologists started using computer tomography (CT). "Tomo" means "slice" or "layer" in Greek. CT produces pictures of multiple "slices" of the human body that are merged into a single image by a computer. Seeing several shadows rather than one makes it possible to visualize many internal organs and their pathological changes, such as tumors or hemorrhages.

Looking at a CT image gives a feeling of travelling inside the human body. Internal organs appear three-dimensional, making it much easier to understand their interactions.

This breakthrough vastly expanded the scope of accurate diagnostics. Thanks to the CT image, a surgeon knows in advance what to expect during the operation. This facilitates his job and reduces the chances of complications.

An early X-ray machine.

An early X-ray machine. Looking at a CT image gives you a feeling of travelling inside the human body.

Unfortunately, X-ray and computer imaging share a common flaw: both involve radiation exposure. However insignificant, this exposure is still a potential hazard for the doctor and the patient, especially if the procedure needs to be repeated.

Magnetic resonance, a safe examination technique

Recent research has led to a fundamentally new, safe, and precise “peeking” technique, known as MRI (magnetic resonance imaging), which measures responses from hydrogen atoms stimulated by a beam of electromagnetic waves.

No radiation whatsoever is involved in MRI tests. They are based on a harmless magnetic field.  

MRI can easily reveal minor inflammations, as well as swelling or tearing of tissue, because the injured spots contain an abnormal proportion of hydrogen (essentially, water). Other problems detected by MRI include intervertebral disk damage, tumors or sclerotic changes in the brain or the spinal cord, and traumatic damage to ligaments, tendons, and menisci. In addition, MRI is so sensitive that it can detect tumors in many organs at a very early stage, when the tumor is still tiny and hardly differs from the adjacent tissue.

  MRI image of a human head

The main advantage of MRI, however, is the total absence of radiation. MRI does not need any X-rays. It is based solely on magnetic resonance. The patient is placed in a strong magnetic field that aligns hydrogen atoms in regular “rows and columns.” A radio wave is then aimed at this “formation.” Depending on the way it is reflected, the computer calculates the proportion of hydrogen in the relevant tissues. A small caveat: a magnetic field attracts iron. It is therefore important that the patient has no steel crowns or prostheses. Even a metal splinter or a minute particle of iron may cause intense pain, so before the test, the patient is asked in detail about any possible sources of metal in his body.

In 2003, Peter Mansfield and Paul Lauterbur were awarded the Nobel Prize in medicine for the discovery of MRI. 

Until recently, patients had to be placed in a special large tube or a box for an MRI test to accelerate magnetic resonance (arranging all the hydrogen atoms in order).

Many of them, however, felt too uncomfortable inside this container. The newer version of the technique, called open MRI, employs a special room (also hermetically sealed) where the patient does not have to suffer being locked “in a box” or, even worse, “in the grave.” He sees the doctor who operates the machine through a window, hears his instructions through earphones, and can use a mike to complain or even stop the test. Thanks to this minor improvement, MRI is fast becoming the most widespread medical imaging test, and a growing number of diagnostic centers are purchasing their own MRI machines.

At our clinic, we also often need to precisely determine the extent and level of intervertebral disk herniation, knee meniscus damage, or a tear of the shoulder joint tendons. MRI diagnostics help design a treatment plan, reduce its length, and ensure fast relief.

I hope this chapter helps my readers to overcome the fear of MRI tests, whether they are afraid of staying in a tight space or exposure to radiation. As you can see, these fears have little to do with reality.