Friday, June 22, 2007
The waiting room is friendly, almost inviting. A look behind the swinging doors reveals just a handful of offices and mostly empty patient rooms. No one is being cut open on operating tables, no one is scrambling frantically in response to nervous sounding pages, no one is making a sound much higher than muted conversation. The pace is leisurely. The mood is sedate. And I haven't once heard anyone request cc's of anything, stat.
Then again, this is what makes radiology so intriguing. The ability to look inside of a human body with mind-boggling precision is granted by techniques so low in risk and so minimally invasive that, from a quick look, it all seems so, well, mundane.
Mundane, until you see the processed pictures...
I am currently splitting my time between Dr. Martin Prince and Dr. Matthew Cham, both of the Radiology Department at New York-Presbyterian Hospital, and Dr. Jonathan Weinsaft of the Cardiology and Nuclear Medicine Departments.
In my first week of the Summer Immersion program, I have observed all three as they made diagnoses, ranging from the typical to the bizarre. Tucked away in an unassuming room, half-seriously dubbed “The Cave,” my advisors analyze series of images and movies streamed from various imaging sites housed throughout a three-block section of uptown Manhattan. Computerized Tomography (CT), Magnetic Resonance (MR), Positron Emission Tomography (PET), Single Photon Emission Computed Tomography (SPECT), it’s all here. The images, splashed across an array of five of the largest LCD screens I have ever seen, offer probing insight into the condition of their subjects. That is to say, in the eyes of a seasoned observer.
“So what do you think is happening here?” they cheerfully ask, as a cine MR sequence is looped across The Wall.
I see a heart beating. It looks fine. I venture a guess.
“It looks like a heart."
I sense they want more.
"...I think it's beating?"
It turns out I was right. Well, somewhat. The patient is suffering from infracted myocardium and irregularly functioning valves, resulting in both mitral valve and tricuspid valve regurgitation. A simple case. A consensus is reached among those present, myself excluded. The final diagnosis is quickly developed and it’s onto the next case. All without ever coming within two blocks of the patient.
“Don’t worry, you’ll pick up on it.”
I hope they’re right.
Thursday, June 21, 2007
I am shadowing Dr. Henschke in the department of radiology at Weill-Cornell medical center. Dr. Henschke started a huge lung cancer screening program using computed tomography (CT) in 1992, and published the first ground breaking paper in 1999 stating that use of CT in high risk groups (i.e. smokers) increases the chance of detecting early lung cancers compared to conventional x-ray. It makes perfect sense (at least to me!) that the earlier you detect cancer, the more effective treatment will be, but nonetheless there has been some controversy around this clinical trial, and this itself motivated me to enter this field and learn how a technical and analytical views of an engineer can contribute in advancing diagnostic or treatment paradigms. I will certainly write more about these controversies later when I get to meet with more physicians in the hospital.
I started off this week by watching Dr. Yankelevitz (Dr. Henschke's collaborator) performing an amazing lung biopsy. He detected a suspicious nodule in the left lung of an 85 year old former smoker, and skillfully inserted a fine needle into the patients back and took a biopsy. These nodules are around 5mm in diameter and it's quite impressive how he inserted the needle right where it should go. Soon after he took the biopsy, he made a microscope slide with quick fixatives and we observed non-small cell cancer pathology under the scope.
During this week I have also shadowed several radiologists in the x-ray reading rooms where they review x-ray or CT of patients on screens and record their diagnosis using a cute little microphone (that's why when you have an x-ray done it will take a while to hear back from the radiologist). I would highly recommend others to go and watch how this reporting is done. They look at the image and read hundred different stuffs in a few minutes! To someone like me everything seems black and white(!!) but there are certainly amazing stories behind!
Now, this is interesting: I went to a clinical pathology conference in cardiothoracic surgery! This is where all of the physicians in that department gather and discuss complicated cases that they're not sure how to proceed. They mentioned a bunch of technical terminology but its interesting to see how they all interact to solve a problem. These sessions also involves interns, residents and fellows presenting and quite honestly this part seemed scary to me! Imagine you're presenting against at least 10 experienced physicians who will bombard you with tough question!
Right now I am scratching my head trying to do some physics and calculate CT dose index and some other radiation properties for another radiologist and tomorrow I will be going to a pulmonary function lab where they get to interview volunteers for the lung cancer clinical trial.
Have fun and seriously do not smoke if you do so!
P.S. Anyone interested in some lung anatomy? Who knows why left lung is taller than right lung? [DO NOT GOOGLE!]
Wednesday, June 20, 2007
As shown in the left figure above, if the myocardium is viable, then it shows up dark in an MRI image. If infarcted myocardium is presented, it will show up as bright region (termed hyperenhancement) as shown in the upper part of the myocardium in the image on the right. The mechanism at the cellular level responsible for hyperenhancement is still not fully understood.
This week I also visit the nuclear medicine laboratory. For cardiovascular disease, the main procedure using SPECT is myocardial perfusion study. This is a form of functional imaging, in which the functional state of the tissue is accessed rather then the anatomical structure of the body. The procedure usually goes as follows: nuclear medicine (usually Tc-tetrofosmin or Tc-sestamibi) is injected into the patient. After the administered of radiopharmaceutical, a stress test is performed to increase the heart rate (either by doing exercise or administered with another drug such as adenosine). Then SPECT images are taken after the test to see the blood perfusion of the myocardium. The underlying principle is that under conditions of stress, diseased myocardium receives less blood flow than normal myocardium.
I found out all these from the technicians in the lab, which is kind of surprising that they know a lot of the theory behind the procedure. During my stay in the lab, it appears to me that the lab with only two SPECT scanners is run by at least 4 or 5 technicians. However, after I talked to them, I found out that it is pretty easy to operate the scanner. They usually assist the patient to get on the bench of the scanner, then adjust several parameters on the computer and let the SPECT scanner runs. The parameters are basically how long the scanner should run depending on the person body size and how many slices of images to take etc. I wonder, shouldn’t these settings be easily calculated by the computer automatically rather then entering manually?
I also found out that my project for this summer is related to another MRI imaging technique called t1 mapping. However, I have no idea what that is. Oh well, this means more reading besides the 20 or so clinical papers Dr. Weinsaft give me on cardiovascular disease diagnosis. Will let u guys know when I find the time to read about it …