MATERIALES Y MÉTODOS
3.1.3. m etoDología De recolecta
A. Decreased abdominal serosal detail may be due to the following:
1. Emaciation
2. Patient age: Animals younger than 6 months will have poor detail
3. Abdominal fl uid or infi ltrative disease (perito- nitis or carcinomatosis)
B. If a mass (can see margins) or mass effect (can- not see margins of mass, but organs are dis- placed) is seen, consider the following: 1. What are the potential organs of origin? 2. What are the differentials for a mass?
a. Neoplasia b. Hematoma c. Granuloma d. Abscess e. Cyst
C. Hernias: Look for abdominal organs in abnormal locations
1. Diaphragmatic 2. Umbilical 3. Inguinal 4. Perineal II. Hepatic disease
A. Generalized hepatomegaly 1. Radiographic fi ndings
a. Caudal displacement of the gastric axis (caudodorsal displacement of the pylorus)
b. Rounding of the caudoventral margin of the liver
2. Differentials should include: Metabolic, endo- crine, infl ammatory/infectious, and diffuse infi l- trative neoplastic disease. Nodular regenera- tion may also be present
B. Focal hepatic mass. Radiographic fi ndings include the following:
1. Displacement of structures (mainly the stomach) based on location
2. Pedunculated masses may extend caudal to the stomach. Differentials include neoplasia, abscess, granuloma, hematoma, and cyst C. Multifocal disease or irregularity of the liver mar-
gins. Differentials would include metastatic neoplasia, nodular regeneration, abscesses, or granulomas
D. Microhepatica (decreased liver size): Cranial dis- placement of the gastric axis
1. Portosystemic shunt 2. Chronic fi brosis or cirrhosis
E. A normal-sized liver does not rule out hepatic dis- ease. Abdominal ultrasound should be performed if clinical signs or laboratory abnormalities sug- gest liver disease
F. Gallbladder
1. Cholecystitis: Radiographs are normal 2. Cholelithiasis: Radiopaque calculi in the gall-
bladder. Most often and incidental fi nding III. Splenic disease
A. Generalized splenomegaly: Evaluation of the spleen for size is extremely subjective 1. Radiographic fi ndings
a. Rounding of the margins b. Increased thickness
2. Differentials include drug-induced (tranquiliza- tion), immune-mediated, infl ammatory or infec- tious, vascular congestion, diffuse neoplasia, and extramedullary hematopoiesis
B. Focal splenic mass 1. Radiographic fi ndings
a. Because the body and the tail of the spleen are very mobile, a splenic mass or mass effect can be seen in almost any location between the stomach and bladder b. With or without abdominal effusion 2. Differentials include neoplasia, hematoma,
abscess, granuloma, and nodular hyperplasia C. Splenic torsion
1. Large, deep-chested dogs 2. Radiographic fi ndings:
a. Abnormal location
b. Moderate to severe enlargement IV. Urinary tract disease
A. Renal and ureters 1. Congenital
a. Renal aplasia, hypoplasia, dysplasia: Kidney is absent or small
b. Ectopic ureters: Survey radiographs are normal
(1) Contrast study should include pneumo- cystography (negative contrast air in- fused in bladder) with a concurrent in- travenous pyelogram (IVP) or excretory urogram (EU); sometimes a positive contrast vaginogram may also be useful (2) Radiographic fi ndings for IVP
(a) Normal to dilated ureters and renal pelves
(b) Ureter bypasses the normal inser- tion at the trigone and empties into the urethra or vagina
2. Renal cysts
a. Solitary cysts: Usually not seen on radio- graphs but can occasionally become large enough to deform the cortex
b. Polycystic kidney disease: Primarily Persian-related breeds. Normal to enlarged kidneys with smooth to irregular margins 3. Pyelonephritis: Radiographs often normal but
may see mild renal enlargement
4. Perinephric pseudocyst: Fluid around the kidney. Enlargement of the renal silhouette; margins are smooth
5. Hydronephrosis: Radiographs are normal until disease becomes severe, then renal enlarge- ment occurs. Often unilateral enlargement but can be bilateral
48 SECTION I GENERAL DISCIPLINES IN VETERINARY MEDICINE
6. Renal neoplasia: Metastatic or primary tumors; may be unilateral or bilateral. Radiographic fi ndings:
a. Kidneys may be normal on survey radio- graphs
b. Uniform to focal enlargement c. Margins may be smooth or irregular 7. Renal mineralization
a. Mineralization may occur in either the renal pelvis (nephroliths) or renal parenchyma (nephrocalcinosis)
b. It is not always possible to tell where the mineralization is located
B. Bladder
1. Bladder rupture. Radiographic fi ndings include the following:
a. Abdominal effusion
b. Best diagnosed with positive contrast cysto- gram
2. Cystic calculi. Radiographic fi ndings include the following:
a. Radiopaque calculi can be seen on survey fi lms: struvite and calcium oxalate
b. Nonradiopaque calculi require ultrasound or a double-contrast cystogram (calculi are visible as fi lling defects in the center of the contrast material)
3. Bladder neoplasia: Usually not seen on survey radiographs unless mineralization is present. Double-contrast cystogram: Irregular mucosal surface with thickened wall
4. Cystitis: Usually normal radiographs unless concurrent calculi present. Double-contrast
cystogram: Irregular mucosal surface with mild wall thickening; usually cranioventral in location 5. Emphysematous cystitis: Air within the wall of
the urinary bladder; sometimes seen in dia- betic patients
C. Urethra
1. Urethritis: Thickening of the wall and irregular mucosal surface seen with a positive contrast urethrogram
2. Ruptured urethra: Leakage of positive contrast into the soft tissues during a urethrogram 3. Urethral calculi: Will see radiopaque calculi on
survey radiographs
a. Take a perineal view in male dogs to assess the penile urethral
b. Calculi will appear as fi lling defects on a positive contrast urethrogram
4. Urethral neoplasia: Thickening of the wall and irregular mucosal surface seen with a positive contrast urethrogram
V. Gastrointestinal (GI) disease A. Esophagus
1. Megaesophagus
a. Focal or generalized; review many causes b. Radiographic fi ndings (Figure 5-5)
(1) Gas, fl uid, soft tissue distention (may be focal or generalized) of the esophagus (2) Dorsal tracheal stripe if gas in the
esophagus dorsal to the intrathoracic trachea
(3) Ventral deviation of the trachea
(4) Aspiration pneumonia: Alveolar pattern in cranioventral lung
Figure 5-5 Lateral (A) and ventrodorsal (B) radiographs of a dog with generalized megaesophagus; the esophagus is fi lled with gas. A, Note the sharp
demarcation between the esophagus and longus coli muscles, the ventral depression of the trachea, the long tracheal stripe sign, and the visibility of the esophageal walls in the caudal aspect of the thorax. A dilated esophagus is more diffi cult to see in the ventrodorsal view, but in this patient note the radiopaque lines paralleling the spine on each side of the thorax and how these lines converge caudally as they approach the stomach (B). (From Thrall DE.
Textbook of Veterinary Diagnostic Radiology, 5th ed. St Louis, 2007, Saunders.)
(5) An esophagram (barium) may be useful for determining the extent
2. Foreign bodies
a. Radiopaque determined based on location from survey radiographs
b. Non radiopaque can be diagnosed as fi lling defects with a positive contrast esophagram B. Gastric disease
1. Gastric dilation (GD)
a. Stomach air, fl uid or ingesta dilated b. Normal positioning
2. Gastric dilation volvulus (GDV) (Figure 5-6) a. Preferred view is right lateral view b. Radiographic fi ndings
(1) Stomach is fl uid, ingesta, or gas dis- tended
(2) Fundus: Displaced caudal, ventral, to right
(3) Pylorus and duodenum: Displaced cra- nial, dorsal, to left
(4) Compartmentalization: Soft tissue band dividing fundus and pylorus
(5) Splenomegaly
(6) Intestinal ileus (dilation of small bowel) (7) Megaesophagus
(8) Hypovolemia (decreased size of cardiac silhouette, pulmonary vessels and cau- dal vena cava)
(9) Plus or minus necrosis of stomach wall: Mural or free peritoneal air
3. Gastric foreign body
a. Easily seen if radiopaque. Zinc toxicity may result from pennies
b. Left lateral view will redistribute gas to py- lorus and may help to outline pyloric for- eign material
4. Gastric neoplasia: Survey radiographs are of- ten normal
5. Gastric emptying disorders
a. Functional ileus versus mechanical obstruction
b. GD even after 24 hours without food (NPO)
c. Radiographic fi ndings
(1). Fluid, gas, ingesta fi lled stomach (2). Often see small mineral opacities at py-
lorus (gravel sign)
(3). Left lateral view is best to assess pylo- rus (foreign material or mural disease- hypertrophy or neoplasia)
C. Small intestine
1. Foreign bodies/intestinal obstruction a. Radiographic fi ndings dependent on dura-
tion of disease, location of obstruction, and degree of obstruction
b. Radiographic fi ndings:
(1) Segmental distention of small intestine (some loops dilated, others normal): Moderate to severe
(2) May see foreign material if radiopaque (3) With or without free gas if intestine has
perforated
c. Linear foreign bodies: Do not see the disten- tion as with other types of obstruction; in- stead, see placation of the bowel (abnormal cresent- or comma- shaped gas pattern) 2. Mural disease
a. Radiographic fi ndings depend on degree of obstruction
b. Most commonly see signs of mechanical ob- struction as listed above for foreign bodies c. Neoplasia: Adenocarcinoma and lymphoma
most common
3. Intussusception: May see intussusception itself but more commonly see signs of mechanical obstruction
4. Enteritis or infl ammatory bowel disease: Nor- mal radiographs to mild generalized distention of small intestine
5. Mesenteric volvulus: Radiographic fi ndings in- clude the following:
a. Severe generalized gas distention of bowel b. With or without free abdominal gas and
fl uid
c. Irregularity to mucosal surface D. Large intestine
1. Colitis: Radiographic fi ndings include (often seen in normal radiographs) the following: a. Fluid-fi lled colon
b. Corrugation
c. Wall thickening: Diffi cult to assess without contrast
2. Neoplasia: May see mural thickening if outlined by gas or distention of the colon if obstructed 3. Megacolon: Functional or mechanical. Radio-
graphic fi ndings include a fl uid or feces dis- tended colon
E. Contrast procedures
1. Pneumogastrogram: Negative contrast in stomach. Useful for identifying foreign material or mural disease
Figure 5-6 Gastric volvulus, right recumbent lateral view. The pylorus (P) is directed cranioventrally. Compartmentalization of the stomach is evident. Most of the small intestine is moderately distended, suggesting paralytic ileus. (From Thrall DE. Textbook of Veterinary Diagnostic Radiology, 5th ed. St Louis, 2007, Saunders.)
50 SECTION I GENERAL DISCIPLINES IN VETERINARY MEDICINE
2. Gastrogram: Positive contrast
a. Useful for identifying foreign material or mu- ral disease and stomach location (hernia or liver size)
b. May have to wait until stomach empties to identify foreign material
3. Upper GI: Barium (15% to 30% wt/vol) admin- istered via a tube into the stomach at approxi- mately 5 mL/lb; radiographs taken immedi- ately, then at various intervals depending on patient disease and motility. Useful for foreign bodies including linear foreign bodies, mural masses, intestinal perforation, location of bowel, and motility disorders (gastric empty- ing or functional ileus)
4. Pneumocolon: Infuse air into descending co- lon. Useful for determining location of colon and mural disease
5. Partial barium enema
a. Administer barium into descending colon b. Useful for determining location of colon and
mural disease
6. Compression radiography: Use a radiolucent spoon to compress area of interest, thus dis- placing overlying structures
a. Useful in areas of the abdomen that are out- side the rib cage
b. Can be used for other organs in addition to the GI tract
VI. Reproductive tract disease A. Prostatic disease
1. The prostate should not be seen in neutered dogs; in intact dogs, it should be less than 70% of the pelvic inlet height and is generally much less than that
2. Prostatic enlargement will result in cranial dis- placement of the urinary bladder and dorsal displacement of the colon
3. Prostatic enlargement may be caused by be- nign hypertrophy (intact male only), prostati- tis, neoplasia, prostatic cyst, prostatic abscess, or paraprostatic cyst
4. If there are medial iliac lymph node enlarge- ment and aggressive bone changes in the cau- dal lumbar spine, then neoplasia is the primary differential
B. Testicle: With cryptorchidism there are usually no radiographic abnormalities. May see as a mass or mass effect in the mid to caudal abdomen if the testicle becomes abnormal (torsion or neoplasia) C. Ovarian disease
1. Ovarian enlargement may result from cyst, ab- scess, or neoplasia (granulosa cell tumor, tera- toma, adenocarcinoma)
2. May not see on radiographs
3. If severely enlarged will see a mass caudal to the kidneys with ventromedial displacement of bowel
D. Uterus
1. The gravid uterus is not recognized on radio- graphs before 25 to 30 days’ gestation 2. Mineralization of the fetal skeleton can be seen
at 42 to 45 days in dogs and 35 to 40 days in cats
3. Fetal death: Radiographic fi ndings include the following:
a. Gas within the uterus or fetus b. Overlapping of bones of the skull c. Lysis of the fetal skeleton
d. Abnormal alignment of the spine and limbs 4. Uterine enlargement: Differentials should in-
clude pregnancy, pyometra, mucometra, and hydrometra. Pyometra shows a tubular mass in the caudoventral abdomen resulting in cra- niodorsal displacement of the small bowel on the lateral view and medial displacement on the VD view. Compression radiography may help identify the uterus between the bladder and colon on the lateral view
VII. Other A. Pancreas
1. Pancreatitis. Radiographic fi ndings include the following:
a. Increased soft tissue opacity caudal to the stomach
b. Decreased serosal detail caudal to the stomach
c. Widening of the gastroduodenal angle or displacement of the proximal duodenum to the right
d. Displacement of transverse colon caudally e. Gas within the duodenum and colon-ileus 2. Pancreatic masses. Radiographic fi ndings in-
clude the following:
a. Mass or mass effect caudal to the stomach b. Displacement of the colon caudally c. With or without abdominal effusion B. Adrenal
1. Adrenal enlargement is usually not seen on survey radiographs unless severe
2. Severe enlargement will result in a mass or mass effect in the retroperitoneal space dis- placing the kidneys caudolateral
3. Hyperadrenocorticism. Radiographs may be normal. Radiographic fi ndings include the following:
a. Pendulous abdomen
b. Diffuse hepatomegaly: Rounding of the caudoventral liver margin
c. Pulmonary mineralization: Diffuse unstructured
d. Mineralization of the skin (calcinosis cutis) or other soft tissues
e. Uncommon to see adrenal mass. Adrenal mineralization can be seen in normal cats or with neoplasia
C. Lymph node
1. Normal lymph nodes are not seen on survey radiographs
2. Radiographic enlargement is generally caused by neoplasia (lymphoma being common) or granulomatous disease. Reactive lymph nodes from other disease rarely get large enough to identify on radiographs
3. Masses or mass effects in the central abdomen and ventral to the caudal lumbar vertebrae (medial iliac)