First week in the big city

The past first week at NYC has already been wonderful! I have always loved this city and everything it has to offer. We've got around walking through central Manhattan, got dinner in some cute and delicious places, and went to see the NYC Philharmonic orchestra in Central Park for free (and fireworks afterwards) 

Back in Ithaca, I work with Dr. Chris Schaffer in developing and using multiphoton microscopy for the study of animal models of neurodegenerative disorders, such as Alzheimer’s disease. My research interests have always been related with imaging, so in this opportunity I got to work with Dr. Martin Prince, which is a world leading expert in Magnetic Resonance Imaging (MRI). MRI has a lot of applications, specially in brain, so I look forward to learn as much as I can and be able to use it on my own research.  Since the day I met Dr. Prince (Monday), I’ve been shadowing him through the MRI facilities and learning how to interpret and diagnose MRI images. At the beginning it was though, since I’m not a physician and sometimes I was asked which part of the body I was seeing in the images. I have to admit that I confused the bladder with the pancreas, and the stomach with the intestine in several occasions. But Dr. Prince patience and remarkable ability to explain things has helped me through the way. It’s also confusing to determine if an image is T1 or T2 (the two basic modalities of MRI images), but now I have learned that in T1 images fluids look dark and fat looks bright, while in T2 images fluids and fat looks bright. I’ve also learnt how to distinguish between the acquisitions modalities, such as gradient echo (GE), spin echo (SE) and proton density (PD). We went to Columbia on Wednesday since Dr. Prince has weekly meetings there with the liver transplant committee. They look at serious cases that need a transplant and determine who gets it based on the images. Also at noon, there is a meeting with other physicians, fellows and residents where they discuss interesting cases of MRI. We talked to one of his collaborators, Dr. Christine Rohde, which is a plastic surgeon specialized in breast reconstruction. I will probably shadow some of her surgeries.

Although I have worked with microscopy during my undergrad and PhD, I feel highly attracted by MRI. Since I studied physics, the mechanism of MRI is really clear to me and I also find it fascinating how is possible to get such a good volumetric imaging and sectioning of the human body. We struggle a lot with scattering and penetration depth in optical microscopy, since light is highly scattered by tissue.

Anyway, during this summer I will be working on a problem that radiologists have been facing for a while. Breast tissue expanders are used for expanding the skin and tissue surrounding the breast cavity after mastectomy has been done in patients with breast cancer. After radiation and chemotherapy, the tissue is scarred, tight and difficult to expand. These expanders possess a magnet that facilitates the access of a catheter that will fill up the expander with saline, silicone or air (depending on the modality). After the expander is completely filled, it can then be replaced with and implant and the breast is ready for reconstruction. In some occasions these patients need MRI to check for additional tumors. The problem is, that since the expander has a magnet on it, is not MRI safe. Contrary to what one would think, numerous studies have been performed with these expanders, people has been imaged with them (and curiously, when the expander is inflated, it tends to push the chest cavity inwards) and everything seems to work just fine. But the real problem is, that the magnet creates a big artifact on the image that literally can spoil the whole study. With Dr. Prince we would like to determine the imaging parameters that can reduce artifacts to the minimum and be able to calculate the volume of chest that has been pushed back by the expander. We got help from the physicists at General Electric (the ones that build the MRI machines) and the parameters they gave us helped us image a patient with tissue expander with the less artifact that they have seen ever. Is possible to see the chest wall perfectly and calculate the volume that has been displaced. Now the idea is to perform this experiments with phantoms and vary the parameters, thus optimizing the images. Dr. Prince currently has data for more than 15 tissue expanders and more than 20 breast implants that could be useful as a positive control, and they have cases every week. So looks like there is material for a publication. Sounds exciting!

 Left: image of the tissue expander that is inserted inside the breast cavity. Right: Phantom we designed with a bag of a saline and a magnet attached to it. This is the phantom we will insert in the MRI machine

Overall, I’ve been pretty busy and I have met a lot of different people, including patients and physicians, which I thought I would never did! I also went into the MRI machine, and it was funny because I had my earrings on, so I could feel how they moved as I approached to it!