Maya Christina Larson, Presenter: Nothing to Disclose

Ralf W. Bauer MD, Abstract Co-Author: Research Consultant, Siemens AG Speakers Bureau, Siemens AG

Josef Matthias Kerl MD, Abstract Co-Author: Research Consultant, Siemens AG Speakers Bureau, Siemens AG

Shuo Zhang MS, Abstract Co-Author: Research collaboration, Siemens AG

Kai Tobias Block, Abstract Co-Author: Employee, Siemens AG

Martin Georg Mack MD, Abstract Co-Author: Nothing to Disclose

Stefan Zangos MD, Abstract Co-Author: Nothing to Disclose

Renate Maria Hammerstingl MD, Abstract Co-Author: Nothing to Disclose

Thomas G. Graf PhD, Abstract Co-Author: Employee, Siemens AG

Thomas Josef Vogl MD, PhD, Abstract Co-Author: Nothing to Disclose

Velopharyngeal dysfunction (VPD) can have many causes. The diagnostic procedures to evaluate the cause for VPD are clinical exam, fibreoptic nasoendoscopy, and videofluoroscopy during speaking and swallowing. During videofluoroscopy the movement of the soft palate, the pharynx, and the closing of the velopharyngeal port are the maneuvers of interest. Unfortunately, videofluoroscopy implicates the application of X-rays which could be avoided by using MR imaging. Thus, the aim of our study was to develop a rapid MRI protocol using equal temporal resolution as fluoroscopy (27 Hz) to demonstrate the velopharyngeal (VP) mechanism during speaking and swallowing without radiation.  

8 healthy volunteers underwent 3.0 T MR functional imaging. Our approach was to use a fast low-angle shot (FLASH) gradient-echo sequence with radial k-space sampling and sliding-window reconstruction (5 subframes) for achieving an image update rate of 27 Hz (27 frames per second). Sagittal single shot views with 8 mm slabs were obtained during speaking and swallowing with a TR of 3.95 ms, a TE of 1.97 ms, a flip angle of 20°, and a matrix size of 128 x 128 pixels. The visibility of the velopharyngeal mechanism during speaking and swallowing was rated by 2 radiologists on a 5 point scale (1 excellent – 5 non-diagnostic).

The obtained real-time MR images (cinematics) were sufficient to evaluate the movement of the soft palate, of the tongue, and the pharyngeal muscles during speaking and swallowing to assess dysfunctions. All volunteers showed a complete closure of the velopharyngeal port. Both radiologists rated the overall image quality in consensus as diagnostic.

The images showed a good air/muscle contrast with a temporal resolution of 27 Hz, which is comparable to fluoroscopic imaging. Therefore real-time MR imaging meets the necessary technical requirements concerning the temporal resolution, but in the long term view the spatial resolution is a parameter that could be improved.  

This new technique can be used as an alternative to fluoroscopy to evaluate the velopharyngeal dysfunction (VPD) during speaking and swallowing without the necessity of application of x-rays radiation

Larson, M, Bauer, R, Kerl, J, Zhang, S, Block, K, Mack, M, Zangos, S, Hammerstingl, R, Graf, T, Vogl, T, Can True Real-time MR Imaging with Radial k-Space Sampling be as Accurate as Videofluoroscopy in the Evaluation of Velopharyngeal Dysfunction during Speaking and Swallowing without Radiation?.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11015527.html