Article
Flat panel volumetric computed tomography: A promising new tool in high resolution skull base imaging
Flächendetektor-Volumen-Computertomographie: Ein viel versprechendes neues Instrument in der hochauflösenden Darstellung der Schädelbasis
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Published: | May 8, 2006 |
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Objective: Due to the introduction of multislice computed tomography (MSCT) scanning times have been markedly reduced and z-axis as well as in-plane resolution have been substantially improved. Though in certain indications, the demand of neurosurgeons concerning spatial resolution are not completely fulfilled. Here we introduce flat panel volumetric computed tomography (fpVCT) as a new approach to improve resolution in the imaging of human skull base.
Methods: The evaluated fpVCT is a newly developed prototype CT currently solely used as an experimental system. The collimated x-ray beam irradiates two silicon flat panel detectors, the z-coverage is 4.2 cm per step. Reconstructed images contain a data set of isotropic voxels with a resolution down to 50µm. Data sets of a prepared skull, six formalin fixed heads and an accident victim with frontal skull base fractures in situ were obtained by fpVCT and reconstructed in 512x512 up to 1024x1024 voxel matrices. Images were compared to those of a state of the art 16-slice MSCT.
Results: The images obtained by fpVCT clearly display smaller details of the bone structures such as small cells of the mastoids, the inner ear, small foraminae and trabeculars for anatomical studies as well as for the visualisation of skull base fractures compared to MSCT. Due to the isotropic voxels of the fpVCT, image quality was equal in all directions in contrast to that of MSCT with substantial loss of resolution in the z-axis. The images of the whole skull base could be reconstructed with a spatial resolution of 150 µm, parts of the skull could be reconstructed with the maximum resolution of 50-100µm.
Conclusions: So far this prototype fpVCT has been introduced for anatomical and functional high resolution imaging in small animals. Now we could demonstrate its potential for future applications in clinical use. For neurosurgeons it is interesting first of all in skull base surgery. Its high resolution of bone structures promises marked improvements of planning skull base approaches or detection of skull base fractures.