Question

1. Compare and contrast MRI and PET imaging. (3 page limit)Your answer should include a discussion of:

1. The technology (how it works)
2. Clinical applications (pros and cons)
3. Safety

Answer 1

MRI Scan:MRI is an abbreviation for Magnetic Resonance Imaging, and it works by measuring the atoms magnetic activities. An MRI scan uses powerful magnetic and radio waves to provide pictures to distinguish between healthy and unhealthy tissues. An MRI scan cannot be done on people who have pacemakers in their heart or have any metal structures inside the body.MRI uses a magnetic field and radio waves to give detailed images of the tissues and organs in the body. The hydrogen atom in every muscle in the body is in different quantity and hence when a scan is done each tissue will interact differently. That means the MRI will produce contrasting images between different tissues. The scanner looks like a giant tube and has a table in the middle where the patient slides in. It differs from CT scan and X-rays as it does not use harmful ionizing radiation.

The characteristics of MRI Scan .

• High definition and a High contrast between soft tissues
• Radiation is non-ionising
• Procures images in any placement
• The images used are for analyzing anatomically
• Noisy and slow

Uses Of MRI scan: These tests are performed by MRI scan center to find out more about ligament injuries, fractures in the bone. It is used in professional sports as a testing measure. It can also be used to detect clots and tumors. The images give a detailed anatomical view of the tissues of the body and also provides reliable information about chemical composition and blood flow. It is the most recommended test for a degenerated disk, ligament tear or types of tumors.

PET scan:

It is an abbreviation for Positron Emission Tomography It measures the positron releasing molecules like oxygen, nitrogen, and carbon and gives valuable data that can be extracted from a PET scanner. It can detect the activity at a cellular level, and the images can help in distinguishing between cancerous tissues and healthy ones. They can produce images which are multidimensional and thus can detect the diseases before it manifests itself in the body. A PET scan cannot replace other imaging tests but is used together with MRI scan and CT scans.

The characteristic of PET scans are

• Produces high-resolution images
• Analyse metabolic processes
• The radiotracer is short-lived after the intake

Difference between MRI scan and PET scan

An MRI can can pick up cancers. But a PET Scan gives more information about the tumor including the tumor activity. PET Scans are also better in assessing tumor response to treatment. So PET Scans are preferred over MRI for cancers