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NFL Injury Diagnostics: Primer on X-Rays, CT Scans and MRIs for the 2013 Season

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The 2013 regular season starts this week, and with it will surely come injuries—likely hundreds when all is said and done.

Many will go unnoticed, unreported or unknown by the press and media, but a few will garner exhaustive coverage and concern—from the teams all the way down to the fans.

Which injures are those?

Those that involve the stars.

To NFL fans, nothing is more agonizing than the waiting that follows their starting quarterback leaving with a knee injury or a wide receiver being carried off on a stretcher.

The hours and days drag on and on as a team's fate hangs in the balance, and an entire fanbase braces for a diagnosis as they replay the injury in their minds.

Jared Wickerham/Getty Images
New England Patriots quarterback Tom Brady went down in 2011 with a torn ACL.

Finally, the inevitable bad news comes:

"Starting player _______ is out _ to _ weeks with a torn/broken _______."


Yet the news is even more crushing when initial reports sounded optimistic—such as those of negative X-rays, for example.

To help clear up what may or may not lie ahead after a player—OK, your player—leaves the game, let's take a brief tour through radiological injury diagnostics.



What are X-rays? What are they used for?

To keep it simple, X-rays look at the bones. Specifically, they look for fractures or joint dislocations, though they can imply—but not diagnose—damage to soft tissues such as ligaments, tendons and other structures.


How quickly are X-Ray results available?

Usually, results are available within a few minutes.

This X-ray shows a broken tibia—or shin bone. The fracture occurred immediately above the ankle. Photo from Wikimedia Commons.

X-rays themselves require just a fraction of a second. Even better, many X-ray machines—certainly those employed by NFL teams, at least—directly link to a computer program, so that the image becomes available the moment the picture is taken.

Most sports medicine physicians and orthopedic surgeons are skilled in the very basics of reading joint and bone X-rays—though teams need radiologists trained in musculoskeletal imaging for a definite, final interpretation.

Nevertheless, diagnoses of obvious fractures are made on the spot, and oftentimes, the news is available by the time of the post-game press conference.


What can fans interpret from reports stating X-rays are negative? What can they not?

As always, each injury is unique. That said, most of the time, it is safe to assume that reports of negative X-rays imply no obvious fractured bones or dislocated joints.

Unfortunately, that's about it.

Ligament tears and tendon ruptures do not show up on an X-ray. Neither do nerve injuries, concussions or organ damage.

Said another way, X-rays are usually just the first of multiple diagnostic imaging tests. Negative X-rays are a good start, but they are also nowhere near the end.


CT Scans

What are CT scans?

Essentially, CT scans—also called CAT scans by some—are many, many X-rays taken at once from thousands of different angles. A computer program then compiles the images into a three-dimensional representation of the body part in question.

This CT scan of the head shows a brain bleed—seen as light-colored material within the brain and highlighted by the red arrows. Photo from Wikimedia Commons.


What are CT scans used for?

When an athlete needs a CT scan immediately following an injury, the entire sports world is usually still holding its breath.


In the context of the high-flying, hard-hitting NFL, medical personnel usually use CT scans to quickly look for one of a few things, each of them scary—even life-threatening.

First, following a hit to the head, doctors and athletic trainers always look for signs of a bleed within the skull. However, small bleeds can remain hidden from clinical observation.

That's where a CT scan comes in.

On CT, blood within the brain shows up as a bright white amongst otherwise-gray brain tissue.

If it shows up on the scan, consultation with neurosurgeons is usually the next step, and emergent brain surgery may follow. Many brain bleeds can quickly progress to coma and death if not intervened upon.

Elsewhere, CT scans allow radiologists to examine the skull and the bones of the spine in much better detail. That way, subtle spine fractures—ones that could potentially threaten the spinal cord if they were to slip out of place—become visible.

Otto Greule Jr/Getty Images
Oakland Raiders cornerback DJ Hayden nearly died last year after a hit to the chest caused massive internal bleeding. Contrast-enhanced CT scans can show internal bleeding, though sometimes they are skipped when the diagnosis is all but certain—possibly the case with Hayden.

Spine X-rays are often sufficient to rule out threats to the spinal cord, but certain circumstances require enhanced detail that only CT can provide.

Finally, if medical personnel inject contrast into an athlete's veins before a CT scan, it becomes possible to visualize how his or her blood is flowing. Such information can alert doctors to internal bleeding—the frightening story of Oakland Raiders cornerback D.J. Hayden comes to mind.


How quickly are CT scan results available?

Alas, with more detail comes more of a need for specialists to interpret CT scans, but obvious bleeds in the brain are visible to anyone with a medical background. However, identifying subtle abdominal bleeds or swelling around the spine require a highly trained eye.

As a result, official reads of CT scans can take an hour or so. Additionally, if an injury mechanism—the direction, magnitude and nature of a hit—is quite suspicious, a repeat CT about four hours later is necessary to confidently take the question of a brain bleed off the table.


What can fans interpret from reports saying CT scans are negative? What can they not?

Most of the time, negative CT scans are very reassuring in the sense that the player's immediate well-being is ensured—simply, there are no immediately obvious brain bleeds, internal bleeds or spine fractures.

However, ligament damage, muscle tears and cartilage injuries need another type of imaging—the MRI.


When it comes to soft tissue detail, nothing beats the MRI, as shown by this knee MRI. Photo from Wikimedia Commons.


What are MRIs?

MRI stands for "magnetic resonance imaging." It is a completely different type of imaging than X-rays and CT scans.

It's also completely confusing.

Without getting too much into electromagnetic physics and advanced chemistry—my brain already hurts—MRIs use alternating magnetic fields to shift the orientation of the protons of water molecules in the body. The shifts are picked up by a computer, which then translates the signals into an extremely detailed three-dimensional picture of the body.

In other words, different types of tissues—muscles, cartilage, ligaments and others—each contain different amounts of water, and the differing amounts of water cause each tissue type to look differently on the computer screen.

The result?

A clear picture of where each ligament, tendon and cartilage group sits.


What are MRIs used for?

While X-rays are the best method of looking at bones, the MRI allows for the examination of soft tissues—ligaments and tendons, for instance.

MRIs can pick up large tears, small tears and even mere tissue swelling, as swollen tissue has different water content than its healthy counterpart.

Swelling without the presence of obvious structural damage implies microscopic tears. Such tears are too small even for an MRI to see, but surrounding inflammation may hint at their existence.


MRIs usually require a patient to lie completely still in a machine such as this for up to an hour or more. Photo from Wikimedia Commons.

How quickly are MRI results available?

One of the biggest setbacks of an MRI is time.

The test itself requires anywhere from 30 to 90 minutes to complete. What's more, though obvious ligament tears are visible without much specialized training, the incredibly complex picture painted by an MRI requires years of experience to decode.

Even then, it's not perfect.

Numerous factors muddy an MRI picture, and a diagnosis may not become apparent for an entire day.

If the diagnosis is a difficult one to make, second opinions, further physical exams and repeat imaging may prove necessary, possibly extending the process to multiple days or even weeks.


What can fans interpret from reports saying MRIs are negative? What can they not?

Unfortunately, this is a tough question to answer.

Technically, a negative MRI would imply no signs of injury whatsoever, but as Bleacher Report's Will Carroll points out, medical jargon confusion may lead to the misinterpretation of media reports.

Does a media report of a negative MRI really mean no visible damage at all? Or does it just mean no obvious tear?

Do you think the public is paying more attention to injuries in the NFL than ever before?

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After all, even though it's probably safe to infer that there are no complete ligament tears from a so-called "negative MRI," low-grade sprains may still bring about missed playing time.

It is also worth pointing out that doctors, trainers and physical therapists do not treat radiographic images. They treat players. It doesn't matter what an MRI says if a player has lost his balance, speed or cutting ability following an injury.


The Bottom Line

The minutes, hours and days following a possible injury to a star player torment fans year in and year out.

However, nothing is worse than expecting the best and later finding out the worst.

So, before dismissing injury reports as insignificant, think back to what they really mean—and what questions still need answering.


Dr. Dave is a resident physician at the University of Washington with plans to pursue fellowship training in Primary Care (non-operative) Sports Medicine. Information discussed above is based on his own knowledge and experience in the Emergency Department, inpatient/hospital and outpatient/clinic settings.

Follow @DaveMSiebert

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