3 Technical Factors Abdomen has low inherent contrast Collimation Lower kVpHigher mAsCollimationHigh amount of scatterUse grid (if patient is >10-11cm thick)Take exposure on expirationMultiple soft-tissue opacity structures surrounded by variable amounts of fat = low inherent contrast.Don’t want mAs too high because of diaphragm motion during respirationUse a grid when the patient is >10-11cm thick.No compression of abdominal organs when expiration.
4 Positioning VD and R lateral views Include from diaphragm to pelvic inletFore limbs pulled craniallyHind limbs pulled caudallyAdditional views as necessaryHorizontal beam VD view = free abdominal gas. (L lateral recumbency)Obliques = renal contrast studiesButt shot = legs pulled forward, to evaluate for urethral calculiLarge dogs = two films may be necessary. Ensure overlap of structures.
5 Sandbags, positioning aids. Radiographic techniques: the dog By Joe P. Morgan, John Doval, Valerie Samii
6 Radiographic techniques: the dog By Joe P. Morgan, John Doval, Valerie Samii
11 Interpretation of Abdominal Radiographs LiverSpleenKidneysGIT (Stomach, SI, Cecum, LI)BladderProstateExtra-abdominal structuresStructures normally seen
12 Structures Not Normally Seen Gall bladderPancreasAdrenalsOvariesUterusUretersLymph NodesMesenteryVasculature
13 Liver Lateral view: VD view: Caudo-ventral margin angular Should not extend beyond the costal archNormal gastric axis parallel to ribs or perpendicular to spineVD view:Liver margins not well seenLong axis of stomach perpendicular to spineNormal gastric axis = a line drawn dorsal to ventral through the stomach in the lateral view)
17 Spleen Size is subjective Lateral view: VD view: Tail of spleen visible, but position variesNot usually seen on this view in catsVD view:Head of the spleen is visualizedCaudo-lateral to stomach fundusCranio-lateral to left kidneyCats : often seen lying along the left body wallNo set size parameters
22 Kidneys Right located cranial to left May be difficult to see in young or emaciated animalsSize (only evaluated on VD view)Dogs: 2 ½ to 3 ½ times the length of L2Cats: 2 to 3 times the length of L2Lateral view = kidneys may be magnified2.4-3
23 Right = renal fossa of the liver Dog – Lateral View
24 Dog – VD ViewDifficult to always visualize both kidneys.
27 Gastrointestinal Tract StomachCaudal to liverGastric AxisLess than 3 ICS wide on lateral viewVD:Dog = U-shapedCat = J-shapedU-shaped = crosses midline. Fundus is left and pylorus is rightJ-shaped = Left cranial abdomen, does not cross midline
31 Gastrointestinal Tract Small IntestineSize: Width less than 3 times the last ribDuodenumFixed along the right sideExtends caudally from the pyloric region of the stomachJejunum/IleumPosition VariesMid-ventral abdomenSmall Intestine contains both air and fluid (Dogs have more gas than cats).Terminal ileum = L1-L3 in mid or dorsal abdomen
33 Gastrointestinal Tract CecumComma shapedMid, right abdomenNot often seen in catsLarge IntestineAscending, transverse and descending colonSize: Width less than 5 times the last ribDogs – cecum is ventral to L3 on lateral and to the right of midline on the VD. Cats – rarely contains gas therefore not visualized routinely.Ascending colon = extends cranially from the cecum to the right of midline.Transverse colon = crosses to the left of midline at approx. L1.Descending colon = Extends caudally to the left of midline until the pelvic inlet.
41 Prostate Intact males ++ Caudal to bladder Symmetrical with smooth marginsSize:Lateral: Less than 70% of sacro-pubic distanceVD: Less than 50% of pelvic inlet widthLarger in intact or older male dogs.Not visualized in male cats.
45 Decreased Abdominal Detail Inability to distinguish organsCauses:Young Animals *Emaciated AnimalsPeritoneal FluidInflammation (Peritonitis, Pancreatitis)Carcinomatosis Normal findingContrast is due to fat, therefore decreased fat = decreased contrastYoung animals = puppies and kittens less than 6-8 months of age