Imaging techniques

Since the times of Galileo, imaging has been considered the "eyes of science". Modern imaging technologies allow the visualization of multi-dimensional and multi-parameter data, leading to significant contributions to understanding biological processes. Different imaging techniques are described below:

  

   Endoscopy:

Endoscopy was first described by Hippocrates in Greece (460-375 BC). The first endoscope was developed in 1806 by Philipp Bozzini with his introduction of a "Lichtleiter" (light conductor). Endoscopy allows the inspection of the inside of the body using a (usually) flexible instrument called "endoscope".

Examples of endoscopy are bronchoscopy, colonoscopy, laparoscopy or gastroscopy, among others.

  

   X-Ray:

X-rays are a type of electromagnetic radiation which, since their discovery in 1895 by Roentgen, have been used in medicine for diagnosis and treatment, generating images of bones, organs, and internal tissues.

Current applications for this method are shown herein:

      1.- Conventional X-Ray. Radiographs are useful for the detection of pathology of the skeleton as well as for detecting some disease processes in soft tissues.

     2.- Computed tomography (CT). In CT, a low energy X-ray source and a detector around the subject is required, acquiring volumetric data. The cross-sectional images are used for a variety of diagnostic and therapeutic purposes:

     3.- Angiography.This imaging technique allows to visualise the trajectory and inside or lumen of blood vessels and organs.

CEREBRAL ANGIOGRAPHY

    Echography

It involves the use of high-frequency sound waves to create images of organs and systems within the body. Ultrasound has developed from 2D to 3D ultrasound recently giving enhanced diagnostic capabilities useful in obstetrics, gynecology as well as cardiology.

                                                        3D ULTRASOUND PICTURE

   Magnetic Resonance Imaging (MRI)

MRI is used in radiology to visualise internal structures of the body in detail by placing a subject in a strong magnetic field. In the clinical practice, MRI is useful for distinguishing altered from normal tissue. A MRI scan can reveal the gross anatomical structure of the human brain:

  Positron Emission Tomography (PET)

In PET, radioactive tracers are incorporated into metabolically active molecules and injected intravenously. PET is useful in system biology studies related to metabolism and metastasis. This method is especially used to detect tumor cells at an early stage as well as to diagnose neurodegenerative disorders such as Alzheimer and Parkinson disease as well as dementia.

 Artificially colour coded whole -body PET scan using 18F-Fluorodeoxyglucose (FDG) 

Imaging technology is in constant evolution, so numerous advances and improvements such as optical coherence tomography, electric impedande tomography, termography or hybrid PET-MR among others have been developed.

Which imaging technique has been used below? Can you identify the elements depicted?

The imaging technique used is MRI, that can reveal incredible data about a person's body, but also about differents elements such as fruits or vegetables, i.e. watermelon, pommegranate or cucumber!! Imaging techniques are not only used  for diagnosis but also for research purposes.

1.- Be able to identify different imaging techniques. 
2.- Know the main characteristics of imaging techniques used in medicine.
3.- Study the applications of the different imaging techniques.