Why do orthopaedic surgeons order so many MRIs? Aren’t x-rays good enough? What’s the difference between an MRI scan and an x-ray?
“It was not an issue before we went on the bye,” Vikings coach Brad Childress said of Favre’s elbow, which first appeared on the injury report before the Sept. 26 game against Detroit.
“We worked pretty good on Monday and Tuesday out here. It flares up every now and again. MRI just says he has a little inflammation. You manage it.”
MRI stands for magnetic resonance imaging. An MRI scan is a detailed way of looking at the inside of the body. Doctors usually order MRI scans to look at things that standard x-rays do not give enough information about. They can be used to diagnose or monitor problems in the human body.
For example, plain x-rays of the knee are cheaper, quicker, and faster than an MRI scan of the knee, but don’t tell the doctor as much detailed information about the parts of the knee anatomy as an MRI scan.
Difference between x-ray and MRI
An x-ray (also called a radiograph) is a digital or film image created by shooting a small dose of radiation through a part of the body. It takes only a few seconds to have an x-ray.
An MRI scanner uses no radiation to create a useful image. Images are made by applying a strong magnetic field to the patient’s body and using a computer to analyze how water molecules in the body respond to those magnetic forces. Most MRIs take about 45 minutes to an hour.
If a part of the body doesn’t contain bone or something with calcium in it, you won’t see it very well on an x-ray. Soft tissue parts like muscle and skin show up as a gray shadow on plain x-ray.
The harder or more calcified something is, the better it shows up on x-rays – therefore, x-rays are very useful for looking at the shapes and positions of the bones of the human body.
MRI, on the other hand, is better in most cases for looking at soft tissue parts that contain more water than hard substances like bone. We all have some level of water in our bones, so they do show up on MRI scans, but not as well as soft parts.
General reasons why doctors might order an MRI
The most common reason MRIs are ordered is to look with more detail at the soft parts of the arms, legs, or spine. Some examples of things that we can look closely at with MRI include:
Many tumors are best evaluated on MRI since they are mostly made of soft tissue.
For example, since ganglion cysts are filled with clear fluid, they show up very obviously on MRI scans since there’s lots of water in that fluid.
Since MRI scans depend on the water or fluid content in the body tissue, you can see swelling and inflammation on these images.
For instance, tendonitis will show up on an MR scan because there’s usually fluid and swelling that goes along with it.
Some high points and facts about MRI
- There is no radiation exposure with an MRI
- MRI scans are much more expensive than plain x-rays (10x or more)
- MRI scans take longer than x-rays
- MRI scans show more detail than plain radiographs
Do you need an MRI?
Most orthopaedic problems can be diagnosed by an orthopaedic surgeon without MRI. Usually plain x-rays, history and physical exam are all that is necessary to make an accurate diagnosis.
One of the best reasons to get a magnetic resonance scan is that the surgeon may use it as a kind of map for surgery.
For example, an MRI may show that a tumor is wrapped around an important nerve or blood vessel, which would be important information for the surgeon.
If your doctor wants to order an MRI, ask the following questions:
- What new information will the MRI reveal that we don’t know already?
- What will be the next step if the MRI is normal/shows a problem?
- Will the results of the MRI change our treatment plan?
- Do I need contrast (an injection) as a part of my scan?
What about claustrophobia?
MR scans are performed in a machine where the patient lies down in a narrow tube. Some patients get anxious in this situation.
Being absolutely still during the scan is critical for a good diagnosis. If the image quality is messed up because you move during the MRI, the images may be useless.
Sometimes a mild sedative will help during the imaging procedure. Ask your doctor about this.
One solution is to have an MRI scan in an “open MRI” machine. This sounds great to patients who are anxious about being in a small tube (in a “closed MRI), but there is a major disadvantage to doing this:
Open MRI scans usually don’t give enough fine detail for an accurate diagnosis in most situations. The smaller the body part (for example, in the finger), the more critical the image quality is.
If you think you might want a scan in an open scanner, ask the ordering physician if the image quality will be good enough for an accurate diagnosis.
All MRI scans are not created equal
These are only a few of the details to consider when getting an MRI scan. Orthopaedic surgeons trust particular radiologists and particular imaging facilities. If a surgeon works closely with a particular MRI technician or radiology team, he may not trust images obtained at another facility. Therefore, don’t be surprised if your doctor is particular about where you get the scan.
Nancy Mummert says
I HAD AN XRAY ON MY SHOULDER AND IT WAS NEGATIVE, SAID WILL DO AN MRI. I HAVE ARTHRITIS. IS THIS NECESSARY?
victoria hathaway says
I have a giant cell tumor on my index finger. One surgeon said to have it with contrast, another said it’s not necessary, actually he said I didn’t even really need the mri. I opted for no contrast. I had the mri. I hope I didn’t make a mistake. The tumor is about the size of a small grape. I just want the best surgeon of course, what do you think?
Dr. Henley says
If you mean “giant cell tumor of tendon sheath”, I usually order an MRI with contrast, but as long as your surgeon and the radiologist are comfortable getting good information from that scan, you should be fine. Make sure you’re seeing a hand surgeon. You can check the assh.org website to find one locally or just type in the term “hand surgeon” and your city to find one.
i am having a mri will moles on the out side of ur body show up on them
Dr. Henley says
I don’t know, but I doubt it.
Thank you for this helpful article. I have a pinched nerve that is causing pain around my right scapula. Thinking I had just pulled a muscle, I lived with the discomfort and took advil on occasion, for about five weeks until I finally couldn’t live with it any longer.
The Dr. x-rayed my shoulder and said it looked normal. She asked me to hold my arm out to the side, lean my right ear towards my right shoulder and then turn my head to the ceiling. This, along with some similar, simple, physical tests, had her diagnose the problem as a pinched nerve. She asked for an x-ray of my neck which showed that three of the vertebrae were straight in a line (not curved as per usual) and that indicated a muscle issue that could be causing the pinched nerve.
The Dr. prescriped a six day course of prednisone and said that should clear it up but, if it didn’t, she would re-evaluate and likely suggest an MRI. The pain was less when I was on the medication but it has since grown worse and more constant. It’s now been two weeks since I stopped the medication and I spoke to the Dr. today. She prescribed a three week course of prednisone and an MRI. Do you think the MRI is necessary?
Dr. Henley says
I would see a spine surgeon before getting the MRI.
If I had a laminectomy surgery and still had pain 5 to 6 months after, is it wrong of my surgeon to not order MRI to see what is going on? My regular doctor ordered but not my surgeon!
Dr. Henley says
Your surgeon should be able to explain his reasons to you. If he can’t or won’t, that would be surprising and unusual.
Basically I got hurt at my car shop and had extreme lower back pain and shooting pain down my leg and some numbness. So I got an MRI that confirmed an L3 L4 disc herniation. We tried conservative treatment and nothing worked so I got surgery a week short of 6 months. A laminectomy on the left L3 and L4. My shooting pain went away but lower back pains and numbness was still there… Five to six months later I asked for an MRI but my insurance wouldn’t pay so my regular doctor ordered one and I payed out of pocket. The MRI showed bulges on all the L discs above and below the L3 L4… And L5 s1 is narrowing as well! At L3 L4 there was a subannualar tear on the left and a bulge and abutment at the nerve. I had nerve tests done that confirmed radiculopathy in my left leg. I was told I might have to have another surgery and it will be a fusion . I Was given a series of shots and physical Therapy and nothing killed the pain… Now my question is: is my nerve damage due to the original herniation from getting hurt at my shop carrying heavy car parts or is it due to the laminectomy surgery (since surgeon did not order MRI even though I complained)? Or did I simply reherniate after a few months and had pain and need another surgery? Lastly is it a negligence of my surgeon to not order MRI sooner to maybe avoid further damage that the MRI (my regular doctor ordered ) showed six months after surgery? Thank u so much. I am just overwhelmed with all kinds of questions…
I have been having pain on the lateral & medial sides of both elbows for over 5 months. I believe the pain was caused by the repetitive work activities that I was doing. The hand surgeon that I went to, said I have bilateral tendonitis. I had an MRI done on my right elbow; but the MRI only showed a subtle edema in proximal common flexor bundle & mild triceps tendinopathy. I’ve been resting for the past 4 weeks and taking a prescription NSAID, but still the pain has dercreased only slightly. Do tendonitis characteristics always show up in an MRI? I do seem to have full range of motion, and no numbness or tingling. Any ideas on what other condition this could be if not tendonitis?
Dr. Henley says
I would encourage you to see a spine doctor who treats these types of problems.
I have had an inner ear infection after a severe bout of acute bronchitis. I took several rounds of antibiotics for this, decongestants and flonase. I also took steriod ear drops, then a round of oral predizone. I am still having ringing in my ears and they make a popping sound when I swallow.
I went to an ENT for this lingering condition and he ordered blood tests and an MRI which has not yet been approved by my insurer. In the meantime, I still have the ringing and popping and a slight soreness in the gland at the back of my throat under my back jaw on the left side. My GP had me hold my nose and blow putting pressure on my inner ear and when I did this, both ears popped.
I think the ENT is caught up on trying to diagnose something obsure and that he was showing off for an intern who was with him that day. The ENT looked annoyed when I suggested that he was overlooking the obvious, that the problem came from the bronchitis attack and not from tumors, autoimmune problems, etc.
I think I simply have not yet cured all the infection. I don’t want to get the MRI. I think Medicare and hospitals are having enough trouble trying to pay for everything without adding more unnecessary testing. I would simply like the ENT to take another look at the obvious, but I don’t want to insult his expertise or intelligence.
What do you think? Thank you very much for your input.
Jane Stegall says
I fell at work on 11/28/2006, hitting the asphalt with my left knee. On Dec. 15th, 2006, Doctors exact notes that day included: She had a big swollen knee, which has gotten somewhat better. At this point she still has some pain. She’s got some ecchymosis all the way down anterior tibia toward the ankle. Has big, swollen, puffy area at the medial joint line and medial side of patella tendon. Looks to be anterior, extraarticular. Patella not particularly tender. No joint effusion. She had MRI which shows a superficial HEMATOMA, but she has nothing intraarticular of significance. Based on this, we’re treating only a superficial contusion of the knee. She’s going to need a little more time. Needs a PAD(?). I think she’ll improve. It may take another month.
It’s almost six years later. The knee has remained sore, as if it’s bruised. I have not been able to put much if any pressure on that knee since I fell. I just thought it’s something I will have to live with. Within the last six months, maybe a little longer, the knee area swell big time and it has become very painful to walk. I have limp around. Since this was workman’s Comp, I was advised to do a RECURRANCE. I made an appointment with my primary care Doctor, which he did an x-ray on Aug. 16, 2012, in his office. Diagnosis: Enthesopathy(?). My Doctor prescribed a topical gel – VOLTAREN, since I am on a blood thinning medication. My Doctor has also scheduled a MRI (Not yet done). Will the new MRI show why I am having so much pain now? I have put on 30 lbs. since I am less active due to the pain it takes to get around. I have 16 steps on my stairs at home. I have to hold on the rails just to get up and down them. I am really getting depressed, as I use to be very active.
Can an MRI tell whether there’s a fracture in the growth plate attached to the the medial epicondilylitis (elbow) if a normal X-ray doesn’t see anything?
Hi, my specialist did a xray on my right hand,and found water in the joint, what does this mean?
I needed to find out if I had arthiritis. All she said was I was in the beginning stage of osteoarthiritis (this was last year 2011). My left elbow is so painful right now, it sometimes feels as though my arm is broken. Is this normal?
C. Noel Henley, MD says
Did you see a hand/arm specialist? Please ask them to take the time to explain what this means.
It’s not normal for your elbow to feel broken. I recommend seeing the specialist or picking a different one.
C. Noel Henley, MD says
Great question – yes!
MRI can detect fluid from an injury that stays in the bone but doesn’t show up on x-ray.
C. Noel Henley, MD says
MRI sounds reasonable if you’re not getting better.
How much does soft tissue swelling interfere with reading an MRI when looking for an occult fracture in the wrist or hand? Thanks in advance.
Nancy: This should not affect the ability of a good radiologist to read the MRI scan at all. A subtle break or crack looks totally different than soft tissue swelling on an MRI. The MRI can “see through” swelling like that.