Kersten Peldschus

Home Institution
Medizinische Hochschule Hannover

Host Institution
Surgical Planning Lab, MRI Division, Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
Research Mentor: Ron Kikinis, M.D.
Clinical Rotations: 1) Dept. of Radiology and 2) Dept. of Neurosurgery, both at Brigham and Women's Hospital

E-Mail: k.peldschus@gmx.de

Research Topic
see Abstract
Personal Reactions to the U.S. Experience
Being in the U.S. for the first time, I was faced with some challenges. My English abilities were not comparable to those who had previously spent a long period of time in English speaking countries. However, this was not a big problem in daily life, but it caused some difficulties in my work place. Even so, many things seemed less formal than in Germany, I needed some time to become aware of American forms of social etiquette. This got me in trouble a few times. Nevertheless, there wasn't anything I could not overcome.
Living in this country and working in a hospital has made me also think about the American health and social care system. The lack of universal health care coverage was a frequently mentioned problem that made people feel uncertain about their futures. I was glad to know that we did not have the same conditions in Germany, although our health care system has its own problems.
Finally, I am thankful to have had these varied and often overwhelming experiences during my time in the U.S. I want to thank all the people who have made this possible.
Greatest Difficulties Encountered
Boston is an expensive city in which to live. Getting a room in an appropriate area for less than $650 U.S. per month was a real challenge. After I had found a place, it did not take a long time until I was faced with another financial difficulty. My wallet was stolen from a locker in a sports club. I did not even have a dollar to get on the T (subway) to go home at that moment. Therefore, it took me about three hours to get to my place and to cancel my credit card in Germany. Unfortunately, it had already been charged 955.40 Euros.
So please keep in mind these emergency numbers for cancellation of German credit/EC-cards.
- Credit card: 011-49-6966571333
- EC-card: 011-49-69740987
Most humorous incident
My roommate came up with a bottle of red Italian wine one night. We started to talk about different types and growth regions of European wine, which are actually quite expensive here in the U.S. Then he opened the bottle, took a nice beer glass (German style), put a couple of ice cubes in it, and filled it up with the wine. So I asked him, "Is it really worth talking about the flavor of wine when you water it down with ice cubes?" But he said his purpose of having the wine was just to fall asleep.
Helpful Hints for Future Students
- Come here to find a room in August, as the academic year starts in the second week of September each year.
- Make sure that you will have a place to stay for your first days in Boston, otherwise looking for a room (www.boston.craigslist.com; www.euroclub.mit.edu) will be even more challenging.
- If you do not get paid by your laboratory, check out the volunteer office in your hospital for several discounts (lunch, T-pass, movie and sport tickets).
- You should have a DB bank account in order to withdraw money without any fee at a Bank of America ATM. There are only two such ATMs in Boston, at Logan Airport Terminal C, and at the Loews Cinema at Boylston Station, Green Line.
- Join Community Boating (www.community-boating.org/index.php) for sailing on the Charles River - Check out www.bssc.com for cheap daily ski trips to New Hampshire, Maine or Vermont. - Take care of your WALLET!

next entry

  table of contents

 

Abstract on Research Topic
Registration of CT/MR images in the Assessment of Cochlear Implant Patients

Author
Kersten Peldschus
Institution
Surgical Planning Lab, Department of Radiology, Brigham and Women's Hospital; Harvard Medical School, Boston, MA
Introduction
The cochlear implant (CI) is an electronic hear prosthesis. It consists of an internal component with an electrode that is surgically inserted into the cochlea of the inner ear, and a portable external device that receives and transmits the acoustic signals. The CI is a standard treatment in patients with profound sensorineural hearing loss in postlingually deafened adults or prelingually deafened children.
Imaging of CI patients is a fundamental part of the whole preinterventional screening process. Computed tomography (CT) and Magnetic Resonance Imaging (MRI) are both used to assess the patients' suitability for a CI as well as to plan the surgical approach. CT and MRI result in complementary information. CT is providing an excellent demarcation of bony structures. MR images show high-contrast representation of the nerves in the internal auditory canal and the fluid filled adjacent structures of the inner ear. In cases of sclerotic and/or fibrotic obliterations it is of special importance to assess the attenuated fluid signal within the cochlea. A CI is possible if a consistent MRI signal remains in at least one of the two scalae, which separate the cochlea into two main tubular structures beside the cochlear duct. However, in severe conditions of obliteration the MRI signal cannot be clearly assigned to one of the scalae when reading the single images of CT and MR.
As a result of the development in image postprocessing and image guided surgery various algorithms of CT/MR registration and image fusion have been reported. However, image registration of the tiny inner structures has not been described yet. This may be due to inefficient registration accuracy with regard to the high-resolution data of both CT and MR of the temporal bone.
Purpose
To evaluate the accuracy of a manual registration/fusion approach of CT/MR images of the temporal bone with respect to intra- and interobserver similarity, and to describe the clinical application of the registration approach for assessment of CI patients.
Material and Methods
We examined 14 patients (5 male, 9 female, average age 24.93, range 2-76). All patients have undergone complete screening for CI including CT and MRI examinations. In 7 patients no radiological abnormalities in both imaging modalities have been reported. Five patients have represented findings of obliteration and 2 have suffered from inner ear malformations.
Registration/Fusion of all 14 patients was obtained retrospectively using the software 3D-Slicer (Surgical Planning Laboratory - www.slicer.org).
A determination of registration accuracy using a consistency measurement was applied to each of the 14 patients. Additionally, to determine the registration accuracy in comparison to a gold standard, we used two temporal bone phantoms with attached external radiological markers (IZI Corp, Baltimore) that are clearly detectable in CT and MR images. Data were analyzed in MATLAB 6.1 (The MathWorks, Inc.).
The results from the accuracy assessment will be evaluated in respect to the anatomical measurements of the cochlea and of the substructures that are detectable in CT and MR Imaging.
Preliminary Results
Registration/fusion of all 14 patients could be carried out. The time of postprocessing varied in a range of 14-35 minutes (mean: 24,8 min). The accuracy analysis is still in progress. Visual assessment provides a first impression of the high accuracy of the registered/fused images (see below).
Possible Conclusions
We are anticipating that we will achieve an accuracy that will demonstrate the suitability of our manual registration/fusion approach for the assessment prior to CI of patients with various types of obliteration or malformation of the inner ear. Therefore the ENT surgeon could be provided with more precise information about the patency of the cochlea and localization of obliterations that may result in an alternative surgical approach in specific cases. Furthermore, the registration method may also be applicable in surgical planning of neurinoma in the internal acoustic canal.