1. SMALL ANIMAL ABDOMEN Chapter 18
Brown: Lavin’s Radiography for Veterinary Technicians Copyright © 2014, 2007, 2003, 1999, 1994 by Saunders, an imprint of Elsevier Inc.

2. Chapter Outline Objectives Key terms Overview Radiographic concerns
Positions
Lateral
Ventrodorsal
Further Views
Normal anatomy
Alternate mode images
Key points
Review questions
Bibliography
When you have finished this chapter, you will be able to:
1. Properly and safely position a dog or cat for the two common abdominal views with an emphasis on where to measure and center, where the borders are, and how to properly position so that the body part is parallel to the image receptor and perpendicular to the beam.
2. Understanding the other views that may need to be completed as alternatives.
3. Identify the normal abdominal anatomy found on a radiograph.
Brown: Lavin’s Radiography for Veterinary Technicians Copyright © 2014, 2007, 2003, 1999, 1994 by Saunders, an imprint of Elsevier Inc.

3. Radiographic Concerns
Similar density and multiple organ systems
Maximize inherent contrast when possible
Better to use higher kVp and lower mAs
See subtle changes better
May need two separate exposures for large dogs
To maximize the inherent contrast of the abdomen when using film/screen systems, keep the following considerations in mind:
Appropriate kilovolt peak (kVp) and milliampere-seconds (mAs) should be used to differentiate the various shades of gray between organs and structures
(generally an average 13- to 15-cm dog would require about 70-kVp and 6-8 mAs for film-based radiography).
Because of the difference in thickness between the chest and caudal abdomen, deep-chested dogs exhibit a marked difference in density between the cranial and caudal halves of the abdomen.
This is especially evident in the ventrodorsal (VD) view.
Two separate exposures measured at the thickest part of each site may be needed.
If there is only a minimal difference in anatomic thickness, a compromise can be made.
Using the same technique with digital radiography may be possible for the full abdomen of such dogs.
Brown: Lavin’s Radiography for Veterinary Technicians Copyright © 2014, 2007, 2003, 1999, 1994 by Saunders, an imprint of Elsevier Inc.

4. Further Considerations
Common views
Right lateral and Ventrodorsal
Take advantage of the heel effect
Use a grid if measurement exceeds 11 cm
Use higher mA to prevent motion artifacts
Take the exposure at the end of expiration.
Consider fasting and enema if needed
Use nonmanual restraint
Consider abdominal compression
The two positions commonly viewed are the right or left lateral and ventrodorsal (Box 18-1).
It is important to be consistent so that abnormalities can quickly be spotted. Contrast studies and other situations may also require further views.
If a right lateral view is used, the animal is lying on its right side.
Technically the correct terminology is left-right lateral (Le-RtL) if one considers, “point of entrance of the beam to point of exit” however, this term is not generally used.
Take advantage of the heel effect (the thickest part toward the cathode) to help reduce density differences, especially in the VD or DV views..
Use a 14 in × 17 in image receptor for large dogs; however, a very large dog will likely require two radiographs. Measure at the respective cranial and caudal abdomen..
A grid must be used if the measurement exceeds 11 cm, to prevent scatter that causes fogging which further decreases the contrast.
To help prevent motion artifacts, use as high a milliamperage setting as possible to produce the shortest exposure setting.
Take the radiograph at the end of expiration, when a brief pause often occurs.
To minimize artifacts and prevent misdiagnosis, fast the patient (if possible) about 12 hours before and administer a cleansing enema about 3 to 4 hours prior to taking a radiograph, to clear the intestinal tract of fecal matter. This preparation is more important for contrast studies.
To minimize radiation exposure to the personnel restraining a patient, nonmanual restraint should be utilized whenever possible. In order to facilitate this, use of a sedative or tranquilizer may be needed. The use of nonmanual restraint is illustrated in most of the following positions. Try to give the patient the illusion that it is being held by appropriate use of sandbags, tape, and so on. For further suggestions, please see Chapter 17 .
Abdominal compression may be utilized to reduce the thickness of the anatomical part. Compression moves an underlying organ to improve the visualization of a suspected lesion as well as reducing the thickness, which decreases scatter radiation. Remeasure the patient after compression has been applied, and use this new thickness to obtain the new kVp.
Brown: Lavin’s Radiography for Veterinary Technicians Copyright © 2014, 2007, 2003, 1999, 1994 by Saunders, an imprint of Elsevier Inc.

5. Prepare and Be Organized
Measure the patient in the position to be imaged.
Have everything ready prior to exposure.
Have everything ready prior to taking the exposure.
This includes:
measuring the animal,
turning on the machine,
setting the main voltage calibration if required,
having proper source-image distance, and
setting the exposures.
Have the image receptors ready.
Positioning devices should be close at hand, but remove any objects or distractions not utilized, to minimize scatter radiation.
The patient should be clean, should have no artifacts in the area of interest, and should be chemically restrained if possible.
Brown: Lavin’s Radiography for Veterinary Technicians Copyright © 2014, 2007, 2003, 1999, 1994 by Saunders, an imprint of Elsevier Inc.

6. Protocol for Abdominal Radiography
Routine views
Right or left Lateral
Ventrodorsal
Optional views
Dorsoventral
Lateral decubitus view
Modified lateral/lateral oblique
Brown: Lavin’s Radiography for Veterinary Technicians Copyright © 2014, 2007, 2003, 1999, 1994 by Saunders, an imprint of Elsevier Inc.

7. Lateral Measure: Central Ray: Borders: Caudal aspect of 13th rib
Canine: Over caudal aspect of 13th rib at level of L2 -L3.
Feline: 2 -3 fingerbreadths caudal to 13th rib.
Borders:
Full peritoneal cavity—T7—greater trochanter
MEASURE:
Caudal aspect of 13th rib (unless interested in a specific region).
CENTRAL RAY:
Canine:
Over caudal aspect of 13th rib at level of L2-L3.
Feline:
Two to three fingerbreadths caudal to 13th rib.
BORDERS:
Collimate cranially from the caudal aspect of T7 (full diaphragm and heart apex) and caudally to the greater trochanter to include the coxofemoral joints (pubic symphysis).
Brown: Lavin’s Radiography for Veterinary Technicians Copyright © 2014, 2007, 2003, 1999, 1994 by Saunders, an imprint of Elsevier Inc.

8. Checklist Settings correct Image receptor/machine/grid in position
Proper location of markers and identification (ID)
Correct body part and view
Properly centered
Borders correct and collimated
Thickest part to the cathode
Patient properly prepared, positioned, and restrained
Image will be perpendicular to the beam and parallel to the film
Full expiration
Quickly go through your mental checklist before pushing the exposure button; the checklist includes the following items:
Settings correct
Image receptor/machine/grid in position
Proper location of markers and identification (ID) (if using at this stage)
Correct body part and view
Properly centered
Borders correct and collimated
Thickest part to the cathode
Patient properly prepared, positioned, and restrained so the image will be perpendicular to the beam and parallel to the film
Full expiration
Brown: Lavin’s Radiography for Veterinary Technicians Copyright © 2014, 2007, 2003, 1999, 1994 by Saunders, an imprint of Elsevier Inc.

9. Lateral Positioning Placement Head Forelimbs Hind limbs Sternum
Place in: Right lateral recumbency.,
This tends to be the conventional position.
Head: Keep in a natural position; hold appropriately with a sandbag over the neck.
Be careful not to restrict breathing.
Forelimbs: Pull cranially and sandbag.
Place a small foam pad between the forelimbs to help eliminate rotation of the cranial abdomen.
Hind Limbs: Pull together caudally and sandbag to prevent superimposition of the femoral muscles, which can mask portions of the urinary bladder and prostate.
Place a foam pad of suitable thickness between the femurs to help eliminate rotation of the caudal abdomen and pelvis.
Sternum: Elevate with wedged sponges so the sternum is at the same plane as the thoracic vertebrae.
Brown: Lavin’s Radiography for Veterinary Technicians Copyright © 2014, 2007, 2003, 1999, 1994 by Saunders, an imprint of Elsevier Inc.

10. Lateral Further Comments and Tips
Images courtesy of Josh Schlote, BS, LVT, Northeast Community College (A) and Rosedale Animal Hospital (B)
Comments and Tips
Place any ID or markers on the ventral aspect of the abdomen.
Ensure that the sternum is parallel to the table and the beam is perpendicular to both.
Expose immediately at the end phase of expiration.
During expiration there is maximum amount of space for the abdominal contents as the lungs contract and the diaphragm relaxes.
Focal radiographs using gentle pressure with a compression paddle such as a wooden spoon or plastic paddle may effectively isolate organs such as the kidneys in a VD position.2
Remember to remeasure the patient because the decreased thickness will allow for a lower kVp and thus more contrast.
There is better longitudinal separation of the kidneys1 in a right lateral view, and the spleen is more consistently identified.
Left lateral is preferable in vomiting patients, because gas is moved to the pyloric antrum and can potentially highlight a foreign body.
A left lateral view may also be required in contrast studies, after the administration of contrast media.
Maximum expiration
Brown: Lavin’s Radiography for Veterinary Technicians Copyright © 2014, 2007, 2003, 1999, 1994 by Saunders, an imprint of Elsevier Inc.

11. Ventrodorsal View Measure: Central Ray: Borders: Widest Part
Canine: umbilicus
Feline: 2-3 fingerbreadths caudal to 13th rib.
Borders:
Full abdomen—T9—greater trochanter
Brown: Lavin’s Radiography for Veterinary Technicians Copyright © 2014, 2007, 2003, 1999, 1994 by Saunders, an imprint of Elsevier Inc.

12. Ventrodorsal Positioning
Placement
Head
Forelimbs
Hind limbs
Maximum expiration
Positioning
Place In: Dorsal recumbency.
A trough may be needed—use clear plastic if possible—and place the device under the thoracic region, not the area being radiographed. This minimizes distortion and artifacts.
Head: Gently pull forward.
If required, carefully position a sandbag over the head and neck, taking care not to restrict breathing.
Forelimbs: Extend forward with sandbags.
If possible, position a sandbag just proximal to the elbows over the limbs.
An alternative is either to tie each limb separately or to place a sandbag over each limb at the carpus and pull cranially.
Hind Limbs: Keep in a natural position, and place a sandbag over each limb.
Brown: Lavin’s Radiography for Veterinary Technicians Copyright © 2014, 2007, 2003, 1999, 1994 by Saunders, an imprint of Elsevier Inc.

13. Ventrodorsal Further Comments and Tips
Maximum expiration
Images courtesy of Josh Schlote, BS, LVT, Northeast Community College (A) and Rosedale Animal Hospital , Toronto, ON. (B)
FIGURE 18-5
A, Ventrodorsal radiograph of the abdomen of a canine .
B, Ventrodorsal radiograph of the abdomen of a 17-year-old feline .
Place any ID or markers adjacent to the corresponding side of the abdomen.
Ensure that the body is evenly positioned so that the two sides of the rib cage appear equidistant.
Ideally a straight line should be imagined connecting the point of the nose with the caudal midline.
Ensure that the sternum and spine are superimposed; image receptor and central ray are perpendicular to both.
Expose immediately at the end phase of expiration (this ensures that the diaphragm is positioned cranially and is not compressing the abdominal contents).
Brown: Lavin’s Radiography for Veterinary Technicians Copyright © 2014, 2007, 2003, 1999, 1994 by Saunders, an imprint of Elsevier Inc.

14. Is the Patient Properly Positioned?
Symmetry and superimposition
Images courtesy Josh Schlote, BS, LVT, Northeast Community College
Ways to determine whether the animal is properly positioned:
Lateral view
Rib heads are superimposed.
Intervertebral foramina are the same size.
Transverse processes are superimposed at the origin from the vertebral bodies.
Coxofemoral joints are superimposed.
Ventrodorsal view
Spinous processes are aligned in the center of the vertebral bodies.
Rib and abdominal symmetry.
Wings of the ilium are symmetrical.
Obturator foramina are symmetrical.
Brown: Lavin’s Radiography for Veterinary Technicians Copyright © 2014, 2007, 2003, 1999, 1994 by Saunders, an imprint of Elsevier Inc.

15. Further Views Dorsoventral View
Measure, center, and borders as per VD
Placement
Head
Forelimbs
Hind limbs
Maximum expiration
Positioning
Place In: Ventral recumbency.
Head: Gently pull forward and carefully place a sandbag over the neck and head taking care not to restrict breathing.
Forelimbs: Extend slightly forward in a fairly natural position.
Place sandbags over each elbow.
Hind Limbs: Keep in a natural position, and place a sandbag over each limb near the stifle.
Image courtesy of Seneca College, Veterinary Technician Program
Brown: Lavin’s Radiography for Veterinary Technicians Copyright © 2014, 2007, 2003, 1999, 1994 by Saunders, an imprint of Elsevier Inc.

16. Dorsoventral Comments and Tips
Image courtesy of Josh Schlote, BS, LVT, Northeast Community College
Place any identification or markers adjacent to the correct side of the abdomen.
Ensure that the body is evenly positioned so that the two sides of the rib cage appear equidistant.
Ideally a straight line should be imagined connecting the point of the nose with the caudal midline.
Ensure that the sternum and spine are superimposed; the image receptor and central ray are perpendicular to both.
Expose immediately at the end phase of expiration. During expiration there is a maximum amount of space for the abdominal contents as the lungs contract and the diaphragm relaxes.
Brown: Lavin’s Radiography for Veterinary Technicians Copyright © 2014, 2007, 2003, 1999, 1994 by Saunders, an imprint of Elsevier Inc.

17. Further Views Lateral Decubitus View
Measure, center, and borders as per VD
Placement
Head
Forelimbs
Hind limbs
Sternum
Comments and Tips
Consider this view if fluid or free gas is suspected, such as in evaluation of gas-capped fluid levels that may be found in an abscess or in a bowel loop, or if the animal will be harmed if placed in an alternate position. Small amounts of fluid may not be identified radiographically.
Positioning
Place In: Right lateral recumbency on a thick foam pad or equivalent (to allow the dependent portion of the abdomen to be in the field of view).
Head: Keep in a natural position and hold appropriately with a sandbag over the neck taking care not to restrict breathing.
Forelimbs: Pull cranially and sandbag. Place a small foam pad between the front limbs to help eliminate rotation of the cranial abdomen.
Hind Limbs: Pull and sandbag caudally to prevent superimposition of the femoral muscles that can mask portions of the bladder and prostate area. Placing a foam pad of suitable thickness between the femurs helps eliminate rotation of the caudal abdomen and pelvis.
Sternum: Elevate the ventral abdomen with wedged sponges so the sternum is at the same plane as the thoracic vertebrae.
The position is described according to the side of the patient closer to the table (i.e., right decubitus if the patient is in right lateral recumbency). Place the image receptor vertically behind the patient.
The horizontal beam will be directed ventrodorsally, entering the sternum and exiting the vertebrae.
Expose immediately at the end phase of expiration; this helps ensure that the diaphragm is positioned cranially and is not compressing the abdominal contents.
Ensure that the sternum and spine are on the same plane; the image receptor and central ray are perpendicular to both.
If free gas is suspected, wait at least 5 minutes once in position prior to the exposure to allow dorsal collection of the gas.
Brown: Lavin’s Radiography for Veterinary Technicians Copyright © 2014, 2007, 2003, 1999, 1994 by Saunders, an imprint of Elsevier Inc.

18. Further Views Modified Lateral
Purpose:
Measure
Central ray
Borders
 Placement
Head
Forelimbs
Hind limbs
Sternum
If evaluation of the entire length of the urinary tract is of concern in a male, the hind limbs may mask the membranous and penile urethra in a true lateral position. There are two alternatives that could be considered—the modified lateral and lateral oblique.
Measure central ray as per the lateral abdomen if imaging a full abdomen.
Positioning
Place In: Right lateral recumbency.
Head: Keep in a natural position, and hold appropriately with a sandbag over the neck.
Be careful not to restrict breathing.
Forelimbs: Pull cranially and sandbag.
Place a small foam pad between the forelimbs to help eliminate rotation of the cranial abdomen.
Hind Limbs: Pull the pelvic limbs cranially as far forward as possible without causing rotation of the body from the film.
An appropriately sized foam pad placed between the femurs may help eliminate rotation of the pelvis.
Place sandbags over the limbs.
Sternum: Elevate the ventral abdomen with wedged sponges so the sternum is at the same plane as the vertebrae.
Have the central ray be perpendicular to both.
Brown: Lavin’s Radiography for Veterinary Technicians Copyright © 2014, 2007, 2003, 1999, 1994 by Saunders, an imprint of Elsevier Inc.

19. Further Views Lateral Oblique
Measure
Central ray
Borders
 Placement
Head
Forelimbs
Hind limbs
Place in: Right lateral recumbency.
Head: Keep in a natural position and support appropriately with a sandbag over the neck.
Forelimbs: Pull cranially and sandbag.
Hind Limbs: Pull the dependent limb caudally and place a sandbag over the femur to keep in position.
Raise the contralateral limb so that it is pulled dorsally and out of the field of view.
A bungee cord or gauze tied around the tarsus and metatarsus and secured to the table, machine or sandbag will help keep the limb out of the field of view.
Brown: Lavin’s Radiography for Veterinary Technicians Copyright © 2014, 2007, 2003, 1999, 1994 by Saunders, an imprint of Elsevier Inc.

20. Modified Lateral/Lateral Oblique
Comments and Tips
Ensure that the pelvic limbs are not superimposed over the caudal aspect of the os penis.
Expose immediately at the end phase of expiration.
For male dogs, this view may be needed because on the ventrodorsal view there may be superimposition of the penis over the bladder.
Oblique views can also be achieved by placing the patient in the VD or DV positions and rotating the body degrees .
This moves the esophagus, stomach, colon and urinary bladder away from the vertebrae to allow better visualization.
The criteria for proper symmetry will not apply.
Brown: Lavin’s Radiography for Veterinary Technicians Copyright © 2014, 2007, 2003, 1999, 1994 by Saunders, an imprint of Elsevier Inc.

21. Abdominal Anatomy
Reprint permission from Dyce, S. a. (2010). Textbook of Veterinary Anatomy. St. Louis, MO: Saunders, Elsevier, 2010 p. 439 Figure 14-7.
A, Transverse section of the canine abdomen at the level of the first lumbar vertebra. B, Corresponding computerized tomography (CT) scan slightly more caudal than the section shown in A; the cat was lying on its back during the CT procedure. 1, First lumbar vertebra; 2, last rib; 3, descending colon; 4, transverse colon; 5, lymph nodes and blood vessels in mesentery, with the jejunum ventral to them; 6, caudal vena cava; 7, aorta, between crura of diaphragm; 8, right kidney; 8, cranial pole of left kidney; 9, descending duodenum and pancreas; 10, greater omentum; 11, linea alba; 12, liver; 13, spleen.
Brown: Lavin’s Radiography for Veterinary Technicians Copyright © 2014, 2007, 2003, 1999, 1994 by Saunders, an imprint of Elsevier Inc.

22. Normal Stomach Position Canine and Feline
Diagrams of normal canine or feline stomach in lateral and ventrodorsal projections.
A, Canine stomach in lateral recumbency.
B, Feline stomach in lateral recumbency.
The gastric axis is parallel with the ribs.
C, Canine stomach in dorsal recumbency.
The gastric axis is perpendicular to the spine, and the stomach is slightly U-shaped.
D, Feline stomach in dorsal recumbency.
The pylorus is located at the midline, and the stomach has more of an acute angle appearing J shaped.
The major areas of the stomach are
F, fundus;
B, body;
A, pyloric antrum;
P, pyloric canal;
C, cardia.
Brown: Lavin’s Radiography for Veterinary Technicians Copyright © 2014, 2007, 2003, 1999, 1994 by Saunders, an imprint of Elsevier Inc.

23. Anatomy of the Abdomen Stomach
Positioning of the canine and feline stomach and its contents depending on the projections
Effects of positional changes as shown in the canine stomach.
A, Right lateral (RtL);
gas is in the fundus (F) and dorsal body of the stomach (B).
B, Left lateral (LeL);
gas is in the main body, pyloric antrum (A) and canal (P), and duodenum.
C, Ventrodorsal (VD);
gas is in the pyloric antrum, body of the stomach, and descending duodenum.
D, Dorsoventral (DV);
gas is in the fundus and cardia (C).
Brown: Lavin’s Radiography for Veterinary Technicians Copyright © 2014, 2007, 2003, 1999, 1994 by Saunders, an imprint of Elsevier Inc.

24. Positional Changes Expiration and Inspiration
Right lateral
Left Lateral
Images courtesy of Josh Schlote, BS, LVT, Northeast Community College
Brown: Lavin’s Radiography for Veterinary Technicians Copyright © 2014, 2007, 2003, 1999, 1994 by Saunders, an imprint of Elsevier Inc.

25. Positional Changes Expiration and Inspiration
VD View
DV View
Images courtesy of Josh Schlote, BS, LVT, Northeast Community College
Brown: Lavin’s Radiography for Veterinary Technicians Copyright © 2014, 2007, 2003, 1999, 1994 by Saunders, an imprint of Elsevier Inc.

26. Evaluation of Urogenital System
FIGURE 18-12
Visceral projections on the left (A) and right (B) canine abdominal walls. 1, Diaphragm; 2, liver; 3, stomach; 4, spleen; 5 and 5, left and right kidneys, respectively; 6, descending colon; 7, small intestine; 7, descending duodenum; 8, pancreas; 9, rectum; 10, female urogenital tract; 11, bladder.
Brown: Lavin’s Radiography for Veterinary Technicians Copyright © 2014, 2007, 2003, 1999, 1994 by Saunders, an imprint of Elsevier Inc.

27. Alternate Modalities
A, Transverse section of the canine abdomen at the level of the first lumbar vertebra. B, Corresponding computerized tomography (CT) scan slightly more caudal than the section shown in A; the cat was lying on its back during the CT procedure. 1, First lumbar vertebra; 2, last rib; 3, descending colon; 4, transverse colon; 5, lymph nodes and blood vessels in mesentery, with the jejunum ventral to them; 6, caudal vena cava; 7, aorta, between crura of diaphragm; 8, right kidney; 8, cranial pole of left kidney; 9, descending duodenum and pancreas; 10, greater omentum; 11, linea alba; 12, liver; 13, spleen.
Brown: Lavin’s Radiography for Veterinary Technicians Copyright © 2014, 2007, 2003, 1999, 1994 by Saunders, an imprint of Elsevier Inc.

28. Comparison of Radiograph Ultrasound Images
Images courtesy of : Josh Schlote, BS, LVT, Northeast Community College (A) and Vetel Diagnostics (B-E)
Comparison of a feline radiograph with various ultrasound images. A , Normal feline lateral abdominal radiograph . B, Sagittal ultrasound image of the liver, gallbladder, and stomach. This is an example of normal liver echogenicity. C, Sagittal ultrasound image of the left kidney. This feline kidney measures smaller than normal (normal is > 3 cm in length) but does have a smooth margin. D, Sagittal ultrasound image of the urinary bladder. This is an example of a normal urinary bladder. E, Sagittal ultrasound image of the spleen. This is an example of a normal feline spleen. Note: Although only one view is being shown here, all studies should be obtained with a minimum of two orthogonal views .
Brown: Lavin’s Radiography for Veterinary Technicians Copyright © 2014, 2007, 2003, 1999, 1994 by Saunders, an imprint of Elsevier Inc.

29. Key Points Use proper exposure
Utilize proper technique and positioning
Right lateral and ventrodorsal are standard
Understand basic anatomy
Other modalities may be best to visualize further structures
Brown: Lavin’s Radiography for Veterinary Technicians Copyright © 2014, 2007, 2003, 1999, 1994 by Saunders, an imprint of Elsevier Inc.

30. Mystery Radiograph
What is the abnormal radiodense material, and where do you think it is located?
Image courtesy of Rosedale Animal Hospital, Toronto, ON
The image is a metal bottle tab that appears to be in the stomach, but one can not be sure until an orthogonal view is taken.
Brown: Lavin’s Radiography for Veterinary Technicians Copyright © 2014, 2007, 2003, 1999, 1994 by Saunders, an imprint of Elsevier Inc.