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IMAGING ESSENTIALS | A B
UÊCranial Border: Place the vertical center of the FOV along the axis of the greater tro- Vh>nÌiÀÊÕ««iÀÊ li}®°Ê/hiÊ}Ài>ÌiÀÊ ÌÀoVh>nÌiÀÊ should be midway between the iliac crest and ischiatic tuberosity. The cranial border of ÌhiÊVollim>ÌoÀÊli}hÌÊ "6®ÊÃhoÕl`ÊLiÊ«l>Vi`Ê cranial to the iliac crest.
UÊCaudal Border: The caudal border of the col- limator light should be placed at the level of the ischiatic tuberosity or caudal skin margin in the perineal region.
Figure 1. Lateral Radiograph of Pelvis (A) Dog positioned for a lateral radiograph of the pelvis. Note the sponge placed between the right and left pelvic limbs and, in this case, the right pelvic limb has been pulled cranially in a scissors fashion. (B) Right lateral radiograph of the pelvis from the dog in A.
ROUTINE RADIOGRAPHIC VIEWS A routine radiographic examination of the pelvis con- sists of two orthogonal radiographs, including a lateral image and an extended leg ventrodorsal image. The ÃÌivliÊ joinÌÃÊ ÌhÀoÕ}hÊ ÌhiÊ liÛilÊovÊ ÌhiÊ«ÀoÝim>lÊ VÀÕÃ®Ê are included in both images.
Lateral Images Positioning For a lateral image of the pelvis, the patient is posi- tioned on the table with the right side down for a right lateral image and left side down for a left lateral image. For cases, such as pelvic fractures or lameness, the side of concern should be the dependent side, which is placed closest to the table. A right lateral image of the pelvis is standard. UÊThe pelvic limbs should be taped separately with a sponge placed between them to ensure that the right and left hemipelves are aligned and directly superimposed.
UÊThe pelvic limb that is closest to the x-ray table is taped in a cranial position, whereas the limb away from the table is placed in a caudal position so the pelvic limbs are in a scissor position, with the stifle joinÌÃÊÃi«>À>ÌiÊ>n`ÊnoÌÊoÛiÀl>««in}ÊFigure 1®°
Collimation -Ì>ÀÌÊLÞÊ ÃiÌÌin}Ê ÌhiÊVollim>ÌoÀÊ li}hÌÊ viil`ÊovÊÛiiÜÊoÀÊ "6®Ê ÌoÊÌhiÊÃ>miÊÃiâiÊovÊ ÌhiÊV>ÃÃiÌÌiÊoÀÊ`iÌiVÌoÀÊLÞÊ
using the corresponding numbers next to the collima- ÌoÀÊknoLÃÊÃiiÊSmall Animal Abdominal Radiogra- phy]Ê oÛimLiÀÉ iVimLiÀÊÓ䣣]Ê«>}iÊxή°Ê/hinÊ>`jÕÃÌÊ ÌhiÊVollim>ÌionÊÌoÊÌhiÊ>VÌÕ>lÊÃiâiÊovÊÌhiÊ«>Ìiin̽ÃÊ«ilÛiÃÊ >n`Ê«ilÛiVÊ limLÃÊ ÌÞ«iV>llÞÊ Ãm>lliÀÊ Ìh>nÊ ÌhiÊoÀi}in>lÊ Vollim>ÌoÀÊli}hÌÊÃiÌÌin}®°
UÊDorsal Border: The vertical portion of the FOV should extend dorsal to iliac crest and }Ài>ÌiÀÊ ÌÀoVh>nÌiÀÊ ÃkinÊm>À}inÊ ovÊ `oÀÃ>lÊ «ilÛiî°
UÊDistal Border:Ê `jÕÃÌÊÌhiÊhoÀiâonÌ>lÊVinÌiÀÊ of the collimator light so that it is midway between the dorsal skin surface and distally includes the stifle joints and proximal crura.
Ventrodorsal Images Positioning The patient should be placed in dorsal recum- LinVÞÊinÊ>Ê«oÃiÌionin}Ê6-ÌÀoÕ}hÊFigure 2,
«>}iÊxä®°Ê1Ãin}Ê>Ê6-ÌÀoÕ}hÊhil«ÃÊkii«ÊÌhiÊ«>Ìiin̽ÃÊÛiÀ- tebral column and sternum aligned and the pelvis in a straight position. To avoid superimposed artifacts from the V-trough, the entire pelvis should be positioned past the edge of the trough and placed on the x-ray table. This positioning also helps decrease geometric magnification of the image. UÊTape the thoracic limbs together and pull them cranially to help align the vertebral column. This, in turn, will aid in keeping the pelvis straight. >VhÊ«ilÛiVÊlimLÊÃhoÕl`ÊLiÊÌ>«i`ÊÃi«>À>ÌilÞÊ>n`Ê extended evenly.
BREED PARTICULARS — Lateral Views In large-breed dogs, such as Great Danes, Doberman pinschers, or mastiffs, the cassette/ detector plate may be turned vertically to encom- pass the entire length of the femurs and pelvis in the dorsal and ventral plane. If needed, the stifle joints can be excluded from the primary
field of view (FOV); additional radiographs centered on the stifle joints can then be taken as needed.
January/February 2012 Today's Veterinary Practice
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Small Animal Pelvic Radiography