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Chapter 7










                                      The Wing: Normal Computed

                                      Tomographic Anatomy





























                    III CONVENTIONAL CROSS-
                         SECTIONAL COMPUTED                              nal tumors. I have yet to have the opportunity to
                         TOMOGRAPHIC IMAGING                             perform magnetography on one of our injured birds,
                                                                         largely because of the high anesthesia risk related to
                                                                         the prolonged examination time required when using

                    For most purposes, conventional biplanar radiography   a low field strength magnet.
                    is quite suitable for routine avian imaging. However,
                    there are instances where extensive hard or soft tissue
                    overlap makes conclusive diagnosis difficult or im-

                    possible. Under such circumstances, cross-sectional   III RECONSTRUCTED THREE-
                    imaging in the form of computed tomography (CT) or
                    magnetic resonance imaging (MRI) warrants consider-      DIMENSIONAL COMPUTED
                    ation. Using these imaging forms, it is possible to      TOMOGRAPHIC IMAGING
                    obtain very thin tissue slices, which by virtue of their
                    diminutive slice thickness (2  mm or less, for example)   Three-dimensional reconstruction (3-D recon) created
                    largely or completely eliminate superimposition      from multiple consecutive cross-sectional tissue slices
                    (Figures 7-1 to 7-3).                                realizes the full diagnostic potential of CT, particularly
                       Using CT, it is also possible to obtain x-ray transmis-  when combined with the ability to manipulate such
                    sion values (Hounsfield units) that are characteristic of   images in three-dimensional space. These anatomical

                    both normal and diseased tissues. These data can then   models may be created with either the dedicated soft-

                    be used to further refine or deny a particular diagnosis,   ware that accompanies most modern CT imagers or
                    as the case may be.                                  can be carried out with standardized digital commu-
                       CT has been found to be most useful in the assess-  nications (DICOM) software. The three-dimensionally
                    ment of complex shoulder injuries in raptors, as well   reconstructed images of an owl’s shoulder are pro-
                    as in the assessment of some types of invasive abdomi-  vided as examples in Figures 7-4 and 7-5.
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