Week #3: Opposite ends of the spectrum

Another week in the trenches and a whole new set of cases that have been read in MRI. I think that my experience with Dr. Prince has been a bit different from everyone else's because my focus is on MRI, not speaking to patients and watching surgeries, but that doesn't make it any less interesting!

We're all engineers or at least aspiring to be engineers and MRI is a great example of how scientists and engineers can reshape the medical field. It can all be traced back to Raymond Damadian's original patent filed in 1971 and issued in 1974 (Pat. No. 3789832). Damadian's patent and several journal articles disclosed that he had discovered certain mouse tumors displayed elevated relaxation times compared to normal tissues. This Damadian hypothesized could be used in humans to identify diseased tissue from healthy tissue with much greater contrast than offered by X-ray and Ultrasound. This discovery combined with recent work in cryogenics made possible the construction of large super-conducting magnets necessary for MR-imaging in humans and thus MRI was born.

The story goes that Damadian and colleagues designed and built their own whole-body super-conducting magnet while at the State University of New York. Here is a diagram from Damadian's 1971 patent showing the MRI device that he had envisioned:

(Image taken from U.S. Patent and Trademark Office)

The first commercial scanner named 'Neptune' was installed at the Hammersmith Hospital in London and had a magnet strength of 0.15T (no that isn't a typo). The most common modern day scanner strength is 1.5T which provides many major improvements over the original 'Neptune'. With the involvement of large corporations like Siemens, GE, and Phillips, and collaboration in the medical research field, MRI has come a long way from the first human images ever reported.

As an interesting aside the 2003 Nobel Prize in Medicine was awarded to Paul Lauterbur and Sir Peter Mansfield for their contributions MRI (Lauterbur's contribution was the discovery that gradients in the magnetic field could be used to generate two-dimensional images and Mansfield analyzed the gradients mathematically). The Nobel committee snubbed Domadian, the pioneer and father of modern day MRI by not awarding him a Nobel Prize. Shortly after the committee's decision, Damadian took out expensive, full-page advertisements in major newspapers to protest their decision - the advertisement can be seen here.

The title of my post this week is "Opposite ends of the spectrum" and it comes from my experience last week of two different memorable cases. In the first case, the patient was 100% ignorant about his health and condition as well as why he was being subjected to an MRI. He had such a lack of interest in his condition and had no desire to help himself that he adamantly refused to be scanned. The second patient was the exact opposite, he was informed (both by the physician and through research he had done independently) and was eager to undergo the MRI to begin to fix the problems with his health.

It seems to me that the most difficult problem in the medical field is getting people to understand - and want to understand - their condition and treatment. From my experience in observing patients being scanned it seems that a majority of them have no clue what is being done or even why it is being done. I have found it rare that a patient has a firm grasp of their condition and treatment that they can have an intelligent discussion with the Radiologist or Physician about it.

In the first case, the patient initially agreed to the scan. The technicians setup the machine, put the patient into the scanner, and began to acquire images. Four minutes into the image acquisition the patient got agitated and wanted to get out the machine. While the cylinder inside the magnet is small, his movements were enough to ruin the images that were acquired. The technician operating the machine got on the speaker and tried to calm the patient down and convince him the lie still so they could finish the scan. The patient suprisingly agreed and they continued to scan.

One minute into the new scan the patient begins to move again and this time seems even more agitated than before. The technician gets on the speaker and tries to calm the patient down. Unfortunately this time he isn't successful. He seemed to have the opposite effect - upsetting the patient even more. The man became so agitated that he began to pull the inside of the scanner apart exposing the fiber-optic lighting system. At this point Dr. Prince decided to stop the scan and pull the patient out.

It took 15+ minutes and the assurance of the doctor, multiple technicians, a few residents and fellows, and some drugs to get the patient to agree to finish the scan. It took a lot of effort to convince one man to sit still for 5 minutes because it was going to benefit his health. After getting the coils realigned, and putting the patient back in the scanner, the technician was finally able to finish.

In contrast, the other case was as easy as it gets because the patient knew what is going on and also had a vested interested in following all of the technicians instructions. Unfortunately, most of the cases are more similar to the former than the latter.

I have learned that the sign of a good technician is someone who can communicate with the patient on a personal level to comfort them during the scan. This desired trait is opposed by the fact that operating a scanner is technically complex and generally best suited for someone who is computer savvy. In laymen's terms, the best MRI technician is a nerd with an amazing personality - this is a hard combination to come by. Sorry if that last comment offended anybody but we all know that nerds are generally socially inept and the inverse is true for socialable people.

Until next week, I hope you all had as good a time as I did observing patients and the weird things they do and say.

Week #2: The Transposition of the Great Vessels

I’ve been silent on the blog for a little bit because I have been putting together a post that doesn’t seems to end. Hopefully I’ll be able to get this all out in one breath – bare with me – here goes …

Week #2 has come and gone in a flash, but not without some interesting cases being read in MRI. I spent the week once again split between Cornell and Columbia Presbyterian Hospital watching my mentor, Dr. Prince, read a variety of cases. For example, we saw cases involving:

• Dilated pancreatic duct
• Kidney and liver transplants (pre- and post-op)
• Multiple cases involving vessel stenoses and aneurisms
• Renal artery
• Common iliac
• Femoral artery
• Profunda
• Superficial femoral artery (SFA)
• and many more …
• Multiple bypass grafts
• Pancreatic carcinoma
• Bicuspid aortic valve
• Hepatic and renal cysts

I am quickly learning that a proficient radiologist must have a thorough understanding of human anatomy and physiology as well as insight into the pathology of diseases affecting all organs and tissues. The radiologist’s job can be boiled down to converting pictures to text in the form of reports, which gives the physicians a clear picture of the patient’s status. Even though a picture is worth a thousand words, it is the radiologist’s job to succinctly convey to the physician what is seen in the MRI and provide quantitative measurements of any observations.

Last week I introduced Contrast-Enhanced MRA and to a lesser extent MRI, which I hope you all are experts in by now. Instead of boring you with more physics and MRI techniques I thought I'd share one of the interesting cases I saw last week: Transposition of the Great Vessels.

Transposition of the Great Vessels is a condition in which the great vessels (the aorta and pulmonary artery) serving the heart are transposed. In a normal heart, the aorta carries blood from the left ventricle to the body and the pulmonary artery carries blood from the right ventricle to the lungs. In a patient with Great Vessel Transposition, the two main arteries serving the heart are switched forcing blood to circulate in only one of two pathways:

1. Oxygenated blood (“Red” blood) is pumped through the left side of the heart to the lungs and back, without entering the rest of the body.
2. Deoxygenated blood (“Blue” blood) is pumped through the right side of the heart to the body and back without entering the lungs.
   

This condition is as serious as it sounds because it destroys the body’s ability to deliver oxygen to the blood serving the entire body. Here is a diagram of the vasculature as it would appear in a patient suffering from Transposition of the Great Vessels:

(Image taken from: http://www.thic.com/transposition.htm)

This is a condition that babies are born with and amazingly, can survive with for a short period of time after birth because of special connections in a newborn heart and blood vessels that help to mix oxygenated and de-oxygenated blood. Generally, babies born with transposition are cyanotic – have blue colored skin, lips, and nail beds – because of low oxygen concentration in the blood.

The first connection present in newborn hearts is the foramen ovale or atrial septal defect (ASD), an opening in the atrial septum between the two atria. Here is a diagram of the location of the foramen ovale:

(Image taken from: http://www.clevelandclinic.org)

The foramen ovale is used during fetal circulation to speed up the circuit time of blood through the heart. Fetuses don’t use their lungs because they receive oxygen rich blood from the mother via the placenta through the umbilical cord. Blood can therefore be directed straight from the right atria to the left atria without a need to travel through the right ventricle and pulmonary artery.

There is a similar hole in the ventricles referred to as the Ventricular Septal Defect (VSD), which joins the right and left ventricles through a patent hole in the ventricular septum. Just as in the foramen ovale, the VSD helps to mix oxygenated blood into the predominantly deoxygenated blood in the right ventricle and aorta.

Normally, the foramen ovale (and VSD) closes at birth due to increased blood pressure on the left side of the heart. The baby as well as the doctors can take advantage of the foramen ovale to prolong life without the need for major surgery. In some cases where the foramen ovale has already closed, minimally invasive catheterization surgery can be performed to make it patent using a small inflatable balloon similar to balloon angioplasty; The procedure is called a balloon septostomy.

The third life-saving connection in newborns with great vessel transposition is a patent ductus arteriosus, a blood vessel that runs between the aorta and pulmonary artery. Here is a diagram of a patent ductus arteriosus:

(Image taken from: http://en.wikipedia.org/wiki/Ductus_arteriosus)

As is the case with the foramen ovale, the ductus arteriosus begins to close shortly after the first breath. Generally, the ductus arteriosus completely closes four to ten days following birth. A small connection between the aortic branch and the left pulmonary artery remains after stenosis of the ductus arteriosus and is called the ligamentum arteriosum. Doctors can delay the stenosis of the ductus arteriosus by administering drugs such as Prostaglandin (Reference).

These three connections aside, no patient can sustain life with transposition of the great vessels because even with patent foramen ovale and ductus arteriosus there isn’t an adequate supply of oxygen to the tissue to maintain its viability, especially considering the added strain of the rapidly developing body.

There are two common surgical procedures used to correct for this malformation of blood vessels:

• Mustard (or Senning) Operation – blood flow is corrected by transposing the pulmonary veins with the systemic veins.
• Fontain Operation – also referred as the Arterial Switch Operation (ASO) – as the name implies this surgical procedure corrects the blood flow by de-transposing the great arteries of the heart.

Choosing the correct surgical procedure can be difficult because there are drawbacks with each. In the Mustard Operation, the procedure is much simpler surgically because veins are much easier to work with. The problem with the Mustard operation is that since the great vessels are still transposed the right side of the heart does the work of the left and vice-versa.

This becomes a problem when considering that each side of the heart performs a different job. The right side is intended to serve the lungs taking in deoxygenated blood from the systemic blood flow and reoxygenating it via the pulmonary arteries. There is considerable less resistance to flow in the right side of the heart and therefore the muscle is weaker than the left.

The left side has a more mechanically stressful job since it is required to push the blood throughout the body. From the start, each side of the heart is designed for different jobs and this means that ultimately the right side of the heart in a patient who has undergone a Mustard operation will fail under the intense stress of the muscle. These patients, whose hearts generally last for 20-30 years, will eventually need a transplant.

The Fontain or Arterial Switch procedure is more difficult surgically because the surgeon has to separate two major arteries (the aorta and pulmonary artery) from the ventricles and reattach them to the correct ventricle while also moving the coronary arteries, which are significantly smaller (1-2mm in an infant) and very important to proper heart growth and function. The pictures below show the patient’s heart pre- and post-operative. The X denotes the location of surgical stitches.

(Images taken from: http://www.driscollchildrens.org)

Normally the coronary arteries originate from the ascending aorta immediately distal from the aortic valve. When a surgeon is performing an Arterial Switch Operation (ASO), they must move the coronary arteries from the right side to the left so that the heart muscle receives oxygen-rich blood. To protect the coronary arteries, the surgeon removes a button of tissue surrounding the coronaries to aid in their attachment to the aorta. Here are two diagrams of the changes that are made during surgery:

(Image taken from: http://www.driscollchildrens.org)

(Image taken from: http://www.driscollchildrens.org)

Essentially, the surgeon excises the aorta and pulmonary arteries just above the valves and frees the coronaries (with additional muscle around it). Next, the surgeon sutures each coronary into place on the left side with fine precision (this can be seen in steps A-C in the first image above). The aorta is then moved into the correct position on the left side of the heart and sutured, above where the coronary arteries were sutured. Next, the two holes in the right side of the heart from the excision of the coronary arteries are patched with pieces of pericardium and the pulmonary artery is attached to the right side (as shown in the left of the first image above). Finally, the foramen ovale and ventricular septal defect are closed and the patent ductus arteriosus is tied off if open.

The surgery is complete but post-operative status is closely watched as complications such as bleeding, and/or myocardial infarction can occur. The patient who I saw this week was scheduled for routine scans to evaluate the condition of his heart. He had undergone a Fontain procedure as a baby and it is common for the patient’s physician to keep a close watch on the health of his heart.

(PAUSE for a quick breath) I guess I couldn’t get it all out in one breath. I hope that you enjoyed this case, I found it very interesting. Stay tuned for my next novel-length post coming soon!

My Campus to Campus

I am so glad that you have tuned in for another thrilling episode. Let’s first start by saying that last week was a short one. I was here from Monday to Wednesday evening, when I left for a gruesome trip back to Ithaca. As I left Olin, to catch the bus, it was storming like crazy. There was heavy rain and electricity in the air. As we left, I was thinking that this was going to be a long trip. Sure enough, a few blocks down was some of NYC’s finest, bumper to bumper traffic. The bus driver was insistent about continuing on down the same path so by the time we were out of traffic; I had whiplash and nausea. Upon arriving in Ithaca after about a 6.5 hour trip, I was starving. After grabbing a quick bite, I immediately began working on my daughter’s bedroom. There was a 5 drawer chest with my name all over it. I finished at about 3 AM. I grabbed a few hours of sleep and was off to the lab. My goal for my time in Ithaca was to run 3 experiments to complete my data set for a potential paper. 2 of the 3 went as expected but some monkey threw a wrench into the other experiment. So, after a superficial analysis, the paper is still moving forward but we will have to see what the data has to say.

Rewind: The “Fat Lip”

During this week, there was more of the same and a few once-in-a-lifetime cases. The first was a severe case of the “fat lip.” This patient was seen by a general practitioner as she had a really fluid-filled lip, a fat lip. There were no obvious culprits as she had received no trauma to the region of her face. This case seemed a little “fishy” and I am sure that the first doctor thought of domestic abuse. Well, it turned out to be much more serious. After CT and MRI, it was determined that the patient had an AVM in her lower lip. You can look back to my previous blog to refresh yourself on AVMs. The treatment for this AVM was embolization. It is hoped that the lack of blood supply will result in shrinkage of the surrounding tissue. If not, an option to be excision by a surgeon in Plastic surgery.

Neck Mass

The next interesting case was a neck mass embolization. This patient, located at Memorial Sloan-Kettering Cancer Center, presented with a complication from a C3-c5 fusion. Sometime ago, this patient was in a bad car accident and suffered from whiplash. This incident caused a crack in one of the vertebrae resulting in the fusion. This fusion was done with the aid of a titanium cage and screws that would allow the bone to the metal structure that was in place for support. That operation was a total success. After sometime at a post-operative check-up, the physician noticed some swelling and tenderness. After imaging, the patient was informed that a tumor was growing around and through the metal cage that was implanted to fix his broken neck.

Our job was embolization. Surgeons at Sloan-Kettering were going back in to remove everything which included all metal implants and the entire tumor. Without embolization, chances were very high the patient could bleed out before the surgeons were through. The patient was embolized, using polyvinyl chloride beads, successfully with few complications.

Well, stay tuned for the next episode. We have several interesting cases on the docket for this week. After three weeks of this, I am pretty comfortable and confident watching most procedures and operations. I have read up on and watched the most common cases several times. I find myself explaining to the newcomers just as people helped me before. I am totally enjoying the experience and can't wait for more.

Image of the Bottom Lip AVM (The "Fat" Lip)

3rd Week and it Feels Like Home

So the third week of the summer immersion program has just wrapped up, and the Weill Medical School is beginning to feel like home (a home away from home), but still a home. This feeling of being part of the hospital stems from the daily interaction with the residents on the 8am rounds in 4 North, the group of clinicians that I interact with on a daily basis where we read MRI, CT, SPECT images, and the nurses that recognize me in the different departments where I observe the procedures. The hospital has become a routine to an extent, but each day there is something new to learn and there is always a new experience to be had, which is the main reason that it keeps this job interesting.

Monday and Tuesday were relatively quiet and non-eventful. I started the days off in the cardiology division of the hospital with rounds with the residents at 8am and then moved on to meet with Dr. Weinsaft and read MRI images. Tuesday had something new to the standard MRI images because we had another clinician that joined us and was looking at the lungs that are in the field of view while you image the heart. By looking at the lungs, the clinician was able to diagnose and pick out small nodules that could potentially be lung carcinoma and warn the patient/physician of these growths. Additionally, this same clinician pointed out to me that you can also see variations in the bone structure and can diagnose problems (such as slipped disks which the patient didn't know they had) and then help treat the condition.

One dramatic image from Tuesday was that a patient came in and had a CT scan done and had been complaining of chest paint amongst other symptoms. The patient was also diagnosed and treated for prostate cancer earlier (which I learned from his medical records) and the CT confirmed that the prostate cancer had begun to spread into the liver and bones (bone pain was another symptom that the patient had complained about). The cancer was readily observable on the CT images especially in the liver where normal tissue appeared a light grey, while the cancerous tissue was spherical and dark. The patients heart turned out to be functioning correctly, but from the CT he had to be informed that his cancer had spread. I don't know how much longer the patient had to live, or if he was going to undergo radiation therapy, but the power of the CT scan demonstrated that many of the diseases that a patient has cannot always just be observable from the outside. The technology of the CT machine allows a very rapid way to image the human body and find where the problems exist without having to use invasive procedures.

Wednesday and Thursday began as the other two previous days had, with rounds in 4 North, some more MRI/CT image reading. On Thursday I had a meeting with Dr. Weinsaft and two other doctors that were involved on a paper that had just been submitted to the American Journal of Cardiology. This paper is currently under review, but the project that I am working on builds off of the previous paper. We met as a group to discuss what I had been doing with the database analysis and setup a time where I could work with one of the clinicians to begin tracing the cardiac MRI images that had been acquired. From my database analysis I had found 19 patients that had a normal heart, but their left ventricle walls had increased in size and mass (this can be caused by high blood pressure, genetic predisposition, and coronary heart disease). In the coming week I will take this group of patients and with the help of another clinician begin on generating numerical values that can be used in the statistical analysis to compare against the data that was obtained for the paper.

Friday was a bit different; instead of starting rounds in 4 North as I had been doing for the last two weeks, I headed down the E 55th St MRI building that houses two more MRI machines in the basement of the building. This building is more a clinic rather than a hospital because many patients do not like to attend a hospital to receive treatment. I spent the day observing MRI images, not just of the heart, but also of the brain, the breast, and lower lumbar regions. Each region of the body has a different way in which it is scanned and there is a different program that is used to generate the image. During this time, two graduate students of Dr. Wang's were present and were also running their algorithm on the patients to determine if their imaging programs functioned. These images then could be compared again the images that are currently being used. One thing that I did realize when the patients got off the MRI table was that they wanted their results automatically and the technicians could not tell them what they had found since they were not specialists nor had the power to diagnose what the patient had. However, while the patient was in the machine, the technicians were readily able to pick out what was wrong with the patient (wall abnormalities in the heart, spread of cancer from the breast, aneurysm in the brain), because of the countless scans that these technicians do on a daily basis. Although the technician knows what they see, they cannot let the patient know anything because it brings up the potential of a malpractice lawsuit for a misdiagnosis where a person that is not legally qualified to diagnosis a condition voices their opinion.

Therefore this third week at the medical school has begun to feel like home and although it is becoming routine (with rounds and reading images) there is always something new to observe and a new case that can be examined, so you'll hardly get bored.