Your guide to choosing the right scan for the right situation.

When It Comes to Medical Imaging, One Size Doesn’t Fit All

Medical imaging is one of the most powerful tools in modern healthcare. It allows doctors to detect disease, monitor progress, and guide treatment—all without a single incision. Among the most advanced imaging modalities available today are PET scans (Positron Emission Tomography) and MRI (Magnetic Resonance Imaging). While both provide essential insights into the body, they serve different purposes and are best suited for different types of conditions.

If your physician has recommended one or both of these scans—or you’re simply trying to understand your options—this guide will walk you through the key differences between PET scans and MRI, when each is used, and how to decide what’s right for you.

What Is an MRI?

Magnetic Resonance Imaging (MRI) uses a powerful magnetic field and radio waves to create detailed images of your body’s internal structures—particularly soft tissues like the brain, spinal cord, joints, and organs.

How It Works:

• You lie in a large, tube-shaped machine
  
• Radio waves are directed through the body
  
• The MRI machine detects how your tissues respond and creates detailed 2D or 3D images
  
• No radiation is used
  

MRI Is Best For:

• Brain and spinal cord imaging
  
• Joint and ligament injuries (knee, shoulder, etc.)
  
• Detecting tumors in soft tissue (brain, liver, uterus)
  
• Diagnosing stroke, MS, and degenerative conditions
  
• Breast and pelvic imaging
  
• Complex anatomy visualization
  

What Is a PET Scan?

Positron Emission Tomography (PET) focuses on how your body functions at the cellular level, rather than just showing its structure. It’s especially valuable in detecting cancer and assessing metabolic activity.

How It Works:

• A small amount of radioactive tracer (commonly FDG) is injected into your bloodstream
  
• This tracer collects in areas of high metabolic activity
  
• The PET scanner detects where the tracer has accumulated, indicating abnormal processes (like cancer cells or inflammation)
  

PET Scans Are Best For:

• Detecting and staging cancer
  
• Determining if a tumor is active or benign
  
• Monitoring response to cancer treatment
  
• Identifying spread (metastasis)
  
• Evaluating heart function and blood flow
  
• Diagnosing Alzheimer’s disease and other dementias
  

PET vs. MRI: A Side-by-Side Comparison

When Are PET and MRI Used Together?

In some complex cases, doctors may order a combined PET/MRI scan, or order both scans separately to gather both anatomical and functional data.

Examples where both are used:

• Evaluating brain tumors (MRI for structure, PET for aggressiveness)
  
• Complex epilepsy mapping for surgical planning
  
• Advanced cancer staging when MRI is needed for soft tissue detail and PET for metabolic activity
  
• Differentiating scar tissue from active cancer in post-treatment cases
  

Combined PET/MRI scanners are now available in some advanced imaging centers, offering both benefits in a single session.

Which Scan Is Right for You?

Choosing between a PET scan and MRI isn’t always straightforward—it depends on what your doctor is looking for.

Here’s a simplified guide:

Choose MRI if:

• You’re dealing with joint, brain, or spinal pain
  
• You need detailed images of soft tissue
  
• You’re being screened for conditions like stroke, MS, or tumors
  
• You want an imaging test without radiation
  

Choose PET Scan if:

• You need to detect or stage cancer
  
• Your doctor needs to know if a tumor is active
  
• You’re monitoring cancer treatment effectiveness
  
• You’re being evaluated for Alzheimer’s, Parkinson’s, or seizures
  
• Your heart’s blood flow or damage from a previous heart attack needs assessment
  

In many cases, your physician may recommend both scans, either together or at different stages of diagnosis and treatment.

Common Questions About PET and MRI Scans

Are PET scans safe?

Yes. The radioactive tracer used in PET scans is low-dose and leaves the body through urine within a day. It’s safe for most people, but pregnant or breastfeeding patients should notify their doctor.

Is an MRI uncomfortable?

While MRIs are safe and painless, they can be noisy and may cause discomfort for those with claustrophobia. At PET CT and MRI of Miami, we offer open MRI options and comfort aids like music, pillows, and blankets.

How long will it take to get results?

Typically within 24 to 48 hours, depending on the complexity of your scan. At our center, urgent cases are prioritized for same-day interpretation.

Why Choose PET CT and MRI of Miami for Your Scan?

At PET CT and MRI of Miami, we’re more than just a diagnostic facility—we’re your imaging partner. Whether you need an MRI, a PET scan, or both, our expert team offers:

• State-of-the-art imaging technology
  
• Board-certified radiologists
  
• Same-day and next-day appointments
  
• Comfortable, patient-friendly environment
  
• Transparent pricing and insurance support
  

We’ll work directly with your doctor to ensure the most appropriate scan is selected—and help you feel informed every step of the way.

About P.E.T. C.T. & MRI of Miami:
Located in South Florida, P.E.T. C.T. & MRI of Miami offers state-of-the-art diagnostic imaging in a supportive, patient-focused environment. From PET and CT scans to MRI, ultrasound, X-ray, and more, we deliver fast, accurate results with your comfort in mind.

Address: 12905 SW 42nd St, Suite 104-106, Miami, FL 33175
Phone: 305-209-2020
Schedule Your Appointment Online: www.petctofmiami.com

Let us know how we can help make your imaging experience easier — we’re here for you.