Biomedical Engineering
Medical Imaging
This guide helps you get your bearings in Medical Imaging before you start exploring the interactive timeline, framework graph, and concept maps.
Before You Dive In
- Medical imaging is where physics, engineering, and medicine converge — each modality (X-ray, CT, MRI, ultrasound, PET) exploits a different physical principle to visualize anatomy or function.
- Start by understanding the physics behind each modality: X-ray attenuation (CT), nuclear magnetic resonance (MRI), piezoelectric sound waves (ultrasound), and radioactive tracer decay (PET).
- Image reconstruction is the mathematical core — especially the Radon transform and filtered back-projection for CT, and Fourier-based k-space reconstruction for MRI.
- The trade-offs between spatial resolution, temporal resolution, contrast, and patient dose define which modality is appropriate for each clinical question.
- Machine learning is rapidly transforming the field, but understanding the underlying physics remains essential for interpreting artifacts and avoiding false confidence in algorithmic outputs.
Key Terms to Know
CT (computed tomography)Uses X-ray projections from many angles, reconstructed mathematically into cross-sectional images.
MRI (magnetic resonance imaging)Exploits nuclear spin precession in a magnetic field; excels at soft tissue contrast without ionizing radiation.
k-spaceThe spatial frequency domain in MRI; raw data is acquired here and Fourier-transformed to produce images.
Filtered back-projectionStandard CT reconstruction algorithm that reverses the Radon transform to build images from projection data.
Contrast agentSubstance administered to enhance differences between tissues, improving diagnostic visibility.
Point spread functionDescribes how an imaging system blurs a point source; characterizes spatial resolution.
Common Confusions
Thinking MRI uses radiation — MRI uses magnetic fields and radiofrequency pulses, not ionizing radiation; CT and PET involve radiation, not MRI.
Assuming higher resolution is always better — increasing resolution often means longer scan times, higher dose, or reduced field of view; clinical imaging is always a trade-off.
Confusing image artifacts with pathology — metal artifacts in CT, motion artifacts in MRI, and acoustic shadows in ultrasound can all mimic or obscure real findings.
Recommended Reading
Foundations of Medical Imaging— Zang-Hee Cho, Joie P. Jones & Manbir Singh
1993Principles of Medical Imaging— Kirk K. Shung, Michael B. Smith & Benjamin M.W. Tsui
2012MRI: The Basics— Ray Hashemi, William Bradley & Christopher Lisanti
2010How to Use the Interactive View
1
Explore the timeline
Open the interactive view and scan the framework timeline. Which frameworks came first? Which ones overlap? Where are the big transitions?
2
Read the articles
Click into individual frameworks to read what each one claims, where it came from, and how it relates to its neighbors.
3
Check the concept map
See how the key ideas within a framework connect. This is useful for figuring out what to learn first and what depends on what.
4
Test yourself
Take the quiz for any framework you've read about. It's a quick way to find out whether you actually understood the core ideas or just skimmed them.