Free Associating in the MRI Scanner…

 

I finished my second MRI scan this year earlier this afternoon. So far lifetime – I have had 5 and will have 6 by the end of next month.  I am sure that many people reading this have had the experience and I would not rate it as pleasant at all.  Just the obsessive checklist that must be completed prior to the scan is enough to raise the anxiety level. Is my body free of implanted or tattooed or accidentally placed metals?  When they were scanning my pancreas – my first thought was: “What about that laparoscopic cholecystectomy I had done in 2019?”  I had read the operative report and it described two permanent clips being placed on the cystic duct prior to dividing it and removing the gallbladder.  I contacted the surgeon about that and he was certain the clips were not ferromagnetic.

One of the last questions is: “Are you claustrophobic?”  And if you are is your primary care doctor prescribing a sedative and if you take that sedative is there somebody here who can drive you home?” I would be hard pressed to think of many people who would not be claustrophobic in an MRI tube.  After all you are in a tight space with very loud noises for a prolonged period. As the radio frequency waves are generated the tube heats up.  It is better than hurtling through space in a larger tube during air travel – and I smiled to myself as I thought of the comparison.

In all cases I have been given a headset and asked about musical preferences and volume.  So far, the headsets don’t block the sound of the machine and obviously are not noise cancellation devices. It did lead me to think about designing headsets without ferromagnetic materials and what that might involve. The only designs I have seen so far use air conduction through tubes rather than electrical connections.

Music selection is as much of a problem as the low-fi headset.  I forgot to ask if I could use my own playlist – but it was safely locked up far away from the 1.5T magnet. I tried to be more specific this time: “Have you got any Canned Heat?”  My most recent play list starts with 3 Canned Heat songs from 1967 – but looking at the tech I estimated he was born in 1980 and the other in the 1990s.  When they rolled me out of the tube one had been replaced by a woman with brightly colored hair who may have been born in the 21^st century.  I changed my answer to “Classic rock.”  That can be a disappointing genre because too much of it is bubble gum music.  Over the 30 minutes in the tube, the heaviest it got was AC/DC Highway to Hell and James Gang Funk 49.  I did enjoy Steve Perry (Journey)  and was tempted to sing along like I do in the car.  But I am sure that would have not been a good idea and may have resulted in additional imaging time and I can no longer hit the high notes.

My mind wandered to fMRI research. How in the world can research subjects be expected to produce real world results from inside the catastrophic MRI world?  I decided not to include my real catastrophic thinking in this post because it is idiosyncratic and I don't want to affect anyone else's decision to get an MRI scan.  And today I just had one or two brief thoughts. I spend most of the time in the tube actively distracting myself and doing sigh breathing exercises to control my heart rate.  Today I opened my eyes in the tube – briefly for the first time.  All I could see was an expanse of whiteness in front of my face with a row of fasteners bisecting the field.  I was pleasantly surprised to find it was about 6 inches away – farther than I had imagined it.  

While I was thinking about research, I also thought about all of the MRI scans I had ordered on my patients.  Going through the procedure yourself leads to questions about the how it is presented to patients for informed consent. I was careful to describe the issues with confined space and noise as well as the advantage of no radiation and better resolution.  Being hospital based, I had the advantage of an anesthesia team being available to sedate and monitor patients who were unable to tolerate it. As I was showing one person their results by holding the film against a window in their room they fainted and I was able to catch them on the way down.  The realistic appearance of the brain in that scan led to that reaction.

Forty years ago, I was an intern in this hospital. My very first rotation was Internal Medicine.  Back in those days it was a county hospital.  Today it is a massive flagship hospital of one of the largest health care organizations in Minnesota. That included a building program to the tune of hundreds of millions of dollars. The original hospital remains at the center, but it is obscured by new wings and buildings. The parking lot I parked in did not exist at the time.  There was a lot out front that you accessed with a magnetic card.  One night I was working late and a guy approached me for money as I entered that lot. I handed him $20 to avoid what I thought might be coming. It was a tough neighborhood.

Once you enter the building – you can step back in time where old meets new.  One of those places is medical imaging. During internship and in the 22 years I worked there radiology (as we used to call it) was one of my favorite haunts. I knew the radiologists and knew I could ask them questions about films.  Surprisingly many of them had questions about psychiatry. Before the electronic health record, I would make a drawing of the positive findings from CT and MRI scans and redraw it in the patient’s chart.  As radiology became digitized it was easier to cut and past images.  I could still discuss images with the neuroradiologist.  I missed all of that when I left that practice.

The MRI tech comes over the headphones:  “OK we are going to come in and inject the contrast.”  They know I had a mild reaction to CT scan contrast but the MRI contrast is gadolinium based and I have had it before.  The last time they checked my pre and post creatinine levels, but at this facility that is replaced by questions about renal insufficiency and dialysis.  That seems like a low bar.  He checks in again in 5 minutes to make sure that I am not having a reaction.

Another sequence of radiofrequency waves starts and there is a pulsating beat that reminds me of a rock and roll song.  I try to recall the song just based on the beat.  I check my muscle tension and realize my shoulders are rolled forward – so I force myself to relax, move my neck, and do some patterned breathing. I would really like to hear some Nirvana at this point.

The tech is on the headphones again.  “OK you are doing great – 5 minutes left.”  That reminded me of a previous scan when I got a similar message and remembered all of the songs that played afterwards.  This time ZZ Top LaGrange comes on. It is a 4 minute song.  At the end – they roll me out of the tube and tell me I have done a great job.

Last night I was wondering whether I was getting progressively more anxious about MRI scans or whether this was a form of exposure therapy. I was surprisingly calm during this one and more confident that I will live to MRI another day.

 

George Dawson, MD, DFAPA

Supplementary:  I have received some early feedback on why I am getting these MRI scans. First and foremost - I am interested in addressing serious problems and preventing disability. I personally know many people who were disabled as the result of spinal injuries that occurred from seemingly trivial events like turning to see someone walking through the door or turning over in bed. I am also aware of age related injuries that occur in active people. Falling off your bike at age 70 is not the same as falling off your bike at age 30 or 40.  All of these scenarios suggest to me that numerous age-related changes in the spine in the absence of any course of effective strengthening can lead to catastrophic problems.   

In addition to the symptoms, I would like to get an opinion of whether it is safe to do aspects of my exercise routine.  I would really like to get back out on the ice speedskating - but I am not going to if it means I will get progressively disabled from spinal problems.  I saw Lindsey Vonn speak to this recently.  I am certainly not comparing myself directly to one of the greatest skiers of all time - but I could relate to why she finally decided to quit.  

“My body is broken beyond repair and it isn’t letting me have the final season I dreamed of,” Vonn said. “My body is screaming at me to STOP and it’s time for me to listen.”   

A lot of aging athletes like myself have the thought that as long as we exercise and stay very active - we will be able to continue in sports as long as we want.  In retrospect, I think I have shown that you can certainly push it much farther than expected and much farther than average - but like the best there is a breaking point. 

Without yet knowing the result of this scan - the possibilities are significant. In the ideal world, it will show age related changes and that would just indicate continuing the physical therapy that I have been doing for 20 years.  If a potential surgical problem shows up that is more complicated.  I do know skaters who have had back surgery and most back surgery has highly variable results. I have also observed and assisted on many back surgeries in medical school where neurosurgery was my preferred surgical rotation - but I assume surgical technique has improved greatly since then.  Would I get back surgery if there was a high likelihood of symptomatic relief and I could return to skating?  Would I get back surgery without that guarantee?  All of that is up in the air at this point. 

Image Credit:  Image credit and Creative Commons licensing can be obtained by clicking directly on the image at the top of this post.

Sedating Patients For Imaging Studies

An article in this week's JAMA hit me like I was still on my old inpatient job.  It was about the issue of sedating patients for imaging studies.  Quality brain imaging - whether it is an MRI or a CT scan depends on the patient being able to lie very still.  Any movement causes artifact that can obscure critical brain areas of interest.  The reasons for the agitation vary quite a bit based on the population but the agitation is not necessarily any easier to treat.  The setting is often different.

As an example, agitated patients on our neurology service when I was an intern were typically agitated due to brain disease.  One of the first patients I saw was elderly and extremely agitated.  Delirium or psychiatric illness was suspected because of examination limitations.  When I examined the patient in the emergency department (ED) - and did the otoscopic exam - there was a large amount of pus coming out of the left ear.  Subsequent lumbar puncture showed that the diagnosis was pneumococcal meningitis.  Like all agitated neurology patients, the chief resident came by and administered intravenous fentanyl.  The junior resident and I stood by next to the CT scanner in the event the patient became excessively sedated or apneic because of the fentanyl.  Without it the CT scan would have been impossible.  She was subsequently admitted to the ICU and had a very complicated course, but eventually survived and left the hospital.

On the psychiatric side. things are a little bit different.  The indications for brain imaging are all based on psychiatric diagnoses.  The medical status of the patient may be completely unknown, based on their ability to cooperative with a review of systems and physical examination.  In most inpatient psychiatry settings these days the patient has come through the emergency department but the complete diagnostic evaluation is deferred to the inpatient side.  Assessment by the inpatient staff the next day may indicate that brain imaging is needed.  The ability to cooperate may vary from an inability to sit still to overt aggression based on the illness.  It is a common occurrence to get a request from radiology to sedate the patient before they go for a brain imaging study.

The issue from an inpatient psychiatric unit is several fold.  Many of the patients are very vigorous and have no physical illnesses.  The medications used on psychiatric units are not anesthetic agents and they do not work immediately.  Psychiatric units are rarely staffed at a level that several physicians can accompany the patient and give them an agent that would work immediately.  Even if they could - the question would be qualifications to supervise that process. At the minimum, they would need to be qualified to administer that agent and manage a cardiopulmonary arrest.  Finally, there is the hospital wide issue of how much support can psychiatry count on.  Can psychiatry for example request an anesthesiology consult for the purpose of imaging study sedation?

In the case report, an elderly man with a BMI of 39 and an history of stable coronary artery disease presented to the ED with dizziness. He ahd associated hypertension, hyperlipidemia, history of carotid endarterectomy, and obstructive sleep apnea (OSA).  He was treated symptomatically with meclizine and ondansetron but a neurology consultant recommended an MRI scan of the brain. He was not able to tolerate the close confines of the MRI scan and was given 1 mg of lorazepam for anxiety reduction.  Over a period of about 15 minutes in the MRI scanner he became incoherent and eventually unresponsive and a cardiac arrest code was called.

The article reviews the errors made in this case beginning with the administration of lorazepam.  Lorazepam is commonly used on inpatient psychiatric units for detoxification, agitation, and insomnia.  The exact dose in this case is a dose that I have administered many times to patients who were going for imaging studies and it is frequently not enough for that purpose.  In this case the patient has OSA and risk factors such as increased age that place him at higher risk for complications.  In this case the authors suggest the minimal dose and if more is needed to monitor heart rate, pulse oximetry and blood pressure in high risk patients.  I would typically do that by requesting an anesthesiology consult for the purpose of sedating the patient for an MRI scan.

Associated measures of care in  this situation include equipment availability.  They recommend the availability of a fiberoptic bronchoscope in case the patient needs immediate intubation and the intubation is difficult.  They consider it to be a priority in the case of patients who have risk factors for airway loss after sedation.   

The American Association of Anesthesiologists has designated dexmedetomidine as a sedative that does not compromise the cardiorespiratory status of patients.  It is a alpha-2 adrenoreceptor agonist.  I did a search on psychiatric applications of dexmedetomidine and the results of that search can be found here.  The package insert discusses the limited applications of ICU intubation and sedation of non-intubated patients for procedures.   

Communicating the patient's OSA status was also viewed as a key error correction process.  OSA is a highly prevalent condition making it more likely that patients with this condition will be sedated for MRI scans.  The suggest including an OSA section in the MRI checklist.

When I think about how this procedure has been done over the course of my career - it was hardly standardized and apart from my neurology team monitoring critically ill neurology patients inside a CT scanner - little monitoring was done.  About 15 years ago that landscape started to change.  Suddenly anesthesiology consults were much easier to get and much more successful.  That was a great relief compared to a process when additional medications were being requested and nobody was there to monitor the patient.  In a few cases, I called off the scan until adequate monitoring could be established.         

The precautions noted in this case report should be studied by every psychiatrist who finds themselves ordering sedation for MRI scans or other procedures.  It is entirely possible that MRI technology may be available in some hospitals but not the appropriate monitoring staff.

In that case I would recommend forgoing the procedure if all of the recommended staff and equipment is not available. 




George Dawson, MD, DFAPA


Reference:

1:  Blay E Jr, Barnard C, Bilimoria KY. Oversedation of a Patient With Obstructive Sleep Apnea Prior to Imaging. JAMA. 2018 Feb 6;319(5):495-496. doi: 10.1001/jama.2017.22004. PubMed PMID: 29411034.  



Graphics Credit:

MRI Images are from Shutterstock per their standard licensing agreement,