Every day, we balance patient comfort, diagnostic quality and safety in an environment where even small oversights can have major consequences.
Implants add another layer of complexity. Some are routine, while others require careful planning. But all of them demand a solid understanding of MRI’s energy sources and a commitment to doing things the right way, every single time.
In this article, I want to share the approach I teach my students and use in my own practice, which is rooted in concepts, not memorization, and built around the MRI Safety Decision Tree. My hope is that this empowers technologists to feel more confident, more prepared and more aware of the impact they can make.
Understanding the Implants We See Every Day
When you’ve been in MRI long enough, you start to recognize patterns.
Orthopedic hardware in hips, shoulders and knees show up constantly. These implants rarely cause issues, and most technologists barely think twice about them. They’re familiar, predictable and generally low-risk.
But then there are the implants that make you do a double-take and pause.
Neurostimulators, for example, require a completely different level of attention. You’re dealing with impedance checks, battery status, MRI mode activation and strict manufacturer conditions. These devices aren’t inherently dangerous, but it’s risky if you skip steps or make assumptions.
You don’t need to memorize every implant; you just need to understand how MRI interacts with them.
The MRI Safety Decision Tree
Implant safety isn’t about memorizing lists. It’s about understanding why something is safe or unsafe.
That’s why I teach using a concept-based approach built around the MRI Safety Decision Tree. It breaks MRI safety into three energy sources:
1. Static magnetic field: Think missile effect, torque and proximity to vital structures.
2. Time-varying gradients: Think induced current, nerve stimulation and noise.
3. RF energy: Think heating, burns and the importance of isocenter.
All implants, passive or active, share one thing in common: they’re inside the patient. That means they’re exposed to the same three energy sources every time they enter the scanner. When you understand those energy sources, you can evaluate any implant, even when you don’t exactly know the make or model.
When you evaluate an implant, ask yourself:
Once you ask these questions, you’ll start to feel more confident when dealing with unfamiliar implants.
Lessons from the Field: When Safety Decisions Matter
The biggest misconception when imaging implants is technologists believing they can cancel an exam due to uncertainty. Canceling an exam is considered practicing medicine, and only a radiologist can make that decision.
Years ago, I had a patient who could barely walk and had almost no strength in their arms. They had a carotid stent, and the technologist I was working with immediately wanted to cancel the exam.
It was five in the morning, and they didn’t think we could reach a radiologist; but we did. We woke someone up, explained the situation and the radiologist approved the scan based on the patient’s symptoms.
That MRI revealed cord compression, a critical finding thatcould have been missed if we had canceled the exam. That’s why the MRI Decision Tree matters and why technologists should never make assumptions about risk.
Building Better Habits
MRI is fast-paced, and shortcuts are tempting, but that’s where safety can get lost.
The most common bad habits I see include:
Skipping the radiologist and canceling exams independently
These may seem small, but they’re the kinds of oversights that lead to burns, injuries and repeat images, putting the patient at risk and, at the very least, requiring that they go through the process an unnecessary number of times.
Good habits, on the other hand, include:
And above all, never get too comfortable. There's always something that will surprise you, or sneak up on you, and you want to make sure you handle it appropriately.
To achieve these best practices, hands-on training and structured education can give technologists the foundation they need to make informed decisions in real time.
Looking Ahead
Implant safety doesn’t have to be scary or intimidating. When technologists learn to break down risk by energy sources, follow the decision tree and collaborate with radiologists, they gain the confidence to handle even the most complex cases.
With the right knowledge, vigilance and willingness to speak up, every technologist has the power to make MRI safer for their patients and their team.