Comparison: Medical Imaging Using Different Techniques - CT Scan

Hi Everyone! We decided to make this post because many of you have doubts about the differences between some diagnostic exams and medical devices that are frequently performed in clinical practice.

So, we are going to present to you some characteristics and functions of the CT Scan, the MRI, the PET scan and the X-ray. 

Part I: CT SCAN

A computerised tomography scan take the idea of conventional X-ray imaging to a new level. Instead of finding the outline of bones and organs, a CT scan machine forms a full three-dimensional computer model of a patient's insides. Doctors can even examine the body one narrow slice at a time to pinpoint specific areas.

The CT scan combines a series of X-ray views taken from many different angles and computer processing to create cross-sectional images of the bones and soft tissues inside your body.

So, a CT scan machine, produce X-rays, a powerful form of electromagnetic energy. X-ray photons are basically the same thing as visible light photons, but they have much more energy. This higher energy level allows X-ray beams to pass straight through most of the soft material in the human body.

http://www.arimaclinic.com/CT/images/ct-scan-of-the-brain.jpg

A conventional X-ray image is basically a shadow: You shine a "light" on one side of the body, and a piece of film on the other side registers the silhouette of the bones. Shadows give you an incomplete picture of an object's shape. If a larger bone is directly between the X-ray machine and a smaller bone, the larger bone may cover the smaller bone on the film. In order to see the smaller bone, you would have to turn your body or move the X-ray machine.

In a CAT scan machine, the X-ray beam moves all around the patient, scanning from hundreds of different angles. The computer takes all this information and puts together a 3-D image of the body. The CAT machine looks like a giant doughnut tipped on its side. The patient lies down on a platform, which slowly moves through the hole in the machine. The X-ray tube is mounted on a movable ring around the edges of the hole. The ring also supports an array of X-ray detectors directly opposite the X-ray tube.

A CT Scan is best suited for viewing bone injuries, diagnosing lung and chest problems, and detecting cancers. Besides this, CT scans are widely used in emergency rooms because the scan takes fewer than 5 minutes.

In addition to be a very good for imaging bone structures, this exam is important in cases of some patients who have received certain types of surgical clips, metallic fragments, cardiac monitors or pacemakers cannot receive an MRI.

(Adapted from: http://science.howstuffworks.com/cat-scan.htm)

https://www.youtube.com/watch?v=tqGmqRrxajQ

New non-invasive method detects early stages of Alzheimer's disease

Hello, dear followers!

We are writing to share with you an incredible non-invasive approach to detect Alzheimer's disease, well before typical symptoms appear. The approach that we are going to share with you uses MRI (Magnetic Resonance Imaging) that pairs a magnetic nanostructure with an antibody that seeks out the beta Amyloid brain toxins which damage neurons and are responsible for the onset of the disease. 

This approach was carried out by neuroscientist William L.Klein and materials scientists Vinavak P.Dravid from Northwestern University. You can check their full article in the Nature Nanotechnology journal by searching for the title: "Towards non-invasive diagnostic imaging of early-stage Alzheimer's disease."

Currently, there is no method capable of detecting Alzheimer's disease, a disease that affects one out of nine people over the age of 65.With MRI it is possible to see the toxins attached to neurons in the brain. The magnetic nanostructures typically with 10-15 nm in diameter are used as smart nanotechnology carriers with antibodies specifically targeted for Amyloid beta toxins.The accumulated toxins, because of the associated magnetic nanostructures, show up as dark areas in MRI scans of the brain.  

a) Fluorescent Amyloid beta oligomers (green), bound to culture hippocampal neurons, were detected with greater than 90 percent accuracy by the NU4 antibody-magnetic nanostructure probes (red). b) MRI signal in vivo of the hippocampal region of the mouse's brain. In diseased models, the toxin's presence can be clearly seen in the hippocampus in MRI scans of the brain. No dark areas were seen in the hippocampus of the control group. (Adapted from Viola et al., Nature Nanotechnology, 2014) 

In this approach the authors detect something different than conventional technologies: they aim for toxic Amyloid beta oligomers instead of plaques, which occur at a very late stage of the disease when the treatment turns out to be less effective. 

In a diseased brain, Amyloid beta oligomers attack the synapses of neurons, destroying memory, ultimately resulting in neuron death. Oligomers may appear more than a decade before plaques are detected. Thus, Amyloid beta oligomers are believed to be the culprit in the onset of the Alzheimer's disease and subsequent memory loss. 

Despite extraordinary efforts there is no effective drug for Alzheimer’s disease yet. However, similar technologies could aid for the assessment of the effectiveness of many drugs on research or clinical trials. According to Dravid, if a drug is effective then the signal from Amyloid beta could become weakened (with less dark areas), so by using these kinds of technologies it would be possible to determine how well the drug is working.

Now we wonder: how many other diseases could be diagnosed by using such amazing technological breakthrough advances? 

Visit the Facebook Page - IBR: Independent Biomedical Researchers

Are you curious? Do you want to be always updated about the latest developments and news about the Biomedical Engineering world? We have a perfect facebook page for you! 

IBR: Independent Biomedical Researchers is a group motivated to explore and deepen topics of interest in the field of Biomedical Engineering. It is formed by students of the Biomedical Materials and Devices Master's Degree of University of Aveiro. Me (Rita) and Diogo are pleased to be members of this group!

The main goals of IBR are:

• To consolidate the background on Biomedical Engineering;
• To encourage the sharing, the exchange of ideas and the enrichment of knowledge;
• To acquire research independence (creation, development, application of strategies for the purpose of obtaining skills), critical thinking and ability to propose solutions to problems of Biomedical Engineering.
• Stay connected and follow us.

Interested? So, follow us through this link: 

https://www.facebook.com/IndependentBiomedicalResearchers