Атлас по рентгенологии травмированных собак и кошек / an-atlas-of-radiology-of-the-traumatized-dog-and-cat

202 Radiology of Abdominal Trauma

	3.1.4.6	Retroperitoneal air		3.1.5	Use of contrast studies in the
	Retroperitoneal air is uncommon and is more often second-				traumatized abdomen
	ary to pneumomediastinum, with the air passing from that re-
	gion into the retroperitoneal space. Another possibility is a			3.1.5.1	Urinary tract trauma
	tearing of the peritoneum and passage of air from the peri-
	toneal space into the retroperitoneal space. Trauma to the			Traumatic lesions of the urinary tract are frequent and excre-
	pelvic region can also permit air to move into the retroperi-			tory urography (Table 3.7) and retrograde urethrocystography
	toneal space. A final possibility is a puncture wound into the			(Table 3.8) can be helpful diagnostically. Excretory urography
	retroperitoneal space with the presence of a gas-producing			is the most easily performed technique, since the trauma pa-
	microorganism. The radiographic features for this condition			tient probably has a venous catheter in place because of a re-
3	involve an increase in contrast created by the air as well as a			quirement for fluid therapy. Therefore, it is convenient to in-
	possible mass effect with abnormal positioning of the adjacent			ject a positive contrast urographic agent at a rate of 1 to 2
	organs (Table 3.6).			ml/kg bw. Radiographs made at 5 to 10 minutes after the in-
				jection will show the bilateral function of normal kidneys. Fol-
				lowing trauma, one or both kidneys can fail to excrete the
	Table 3.6: Radiographic features of retroperitoneal air			contrast agent because of renal artery thrombosis, renal artery
				tear, avulsion of the kidney, or kidney injury. The contrast
	(Cases 3.9 & 3.17)
				agent can accumulate within the renal subcapsular space indi-
	1. Increased visualization of the
				cating renal laceration. If the contrast agent leaks into the
	a. sublumbar muscles (quadratus lumborum, psoas major, psoas minor)			retroperitoneal space this indicates renal laceration or ureteral
	b. kidneys
				tear. The contrast agent can also leak into the peritoneal space
	2. Ventral displacement of
				if the peritoneum is torn subsequent to any of these injuries.
	a. kidneys
				Sequential radiographs will show the character of the ureters,
	b. small bowel
				the position of the urinary bladder, and the status of the blad-
	c. descending colon and rectum
	3. Secondary to			der wall.
	a. pneumomediastinum			If it is possible to catheterize the urinary bladder in a retro-
	b. peritoneal air
	c. subcutaneous emphysema or infection			grade direction, the location of the bladder, the status of the
	d. pelvic canal air			bladder wall, and the status of the urethra can be determined.
				The urethra is evaluated following repositioning of the
				catheter tip so that it lies within the distal urethra.

3.1.4.7Organ enlargement

Enlargement of solid parenchymatous abdominal organs in cases of trauma can be due to subcapsular or encapsulated hemorrhage following hepatic, splenic, or renal injury. Enlarged renal shadows can also be due to hydronephrosis following ureteral rupture. Since the fluid is contained beneath the capsule, the border of the organ remains visible on the radiograph, but the organ can appear larger, or with a different shape or contour than usual. This radiographic feature is not commonly seen.

3.1.4.8The pelvis

In the event of generalized trauma, pelvic radiographs are relatively easy to perform and permit the evaluation of the soft tissues containing the distal colon and rectum, plus the terminal ureters, urinary bladder, and urethra in addition to the caudal lumbar vertebra, lumbosacral junction, sacrum, caudal vertebrae, sacroiliac joints, pelvis, hip joints, and the proximal femurs. Any of these structures can be traumatized and require treatment. Often a combination of injuries effecting both the soft tissues and bone or joint is present (See also Chap. 4.2.16 Pelvis).

Table 3.7: Radiographic features of excretory urography in trauma patients

(Cases 3.18, 3.20, 3.23, 3.24, 3.27, 3.29 & 3.32)

1.Failure of normal renal opacification/excretion by contrast agent because of a

a.torn renal artery

b.torsion of the renal artery

c.thrombosis of a renal artery

2.Extravasation of contrast medium into the

a.subcapsular space because of renal laceration

c.peritoneal space because of renal laceration and capsular tear

d.retroperitoneal space because of renal laceration and capsular tear

e.retroperitoneal space because of ureteral tear

3.Hydronephrosis because of ureteral injury

4.Hydroureter because of ureteral injury

5.Failure of normal visualization of urinary bladder because of

a.renal or ureteral injury that fails to funnel contrast agent into bladder

b.incomplete filling of bladder because of tear in the bladder wall

6.Peritoneal extravasation of contrast agent because of bladder wall tear

7.Extravasation of contrast agent into the pelvic spaces because of

a.bladder neck injury

b.proximal urethral injury

c. tear		4. Failure of transit of contrast agent	203
		Use of contrast studies in the traumatized abdomen
Table 3.8: Radiographic features of retrograde urethrography/		Table 3.9: Radiographic features of gastrointestinal trauma
cystography in trauma patients		following orally administered contrast agent
(Cases 3.12, 3.19, 3.20, 3.21, 3.22, 3.25, 3.26, 3.27, 3.28, 3.29 & 3.30)		(Cases 3.3–3.9)
1. Extravasation of contrast medium into the		1. Displacement of
a. peritoneal space because of bladder wall injury		a. gastro-esophageal junction
b. peritoneal space because of proximal urethral injury		b. stomach
c. pelvic space because of		c. small bowel
I. proximal urethral injury		2. Distention of
II. bladder neck injury		a. stomach
d. peri-urethral space because of urethral injury		b. small bowel
2. Contrast column may indicate an abnormal mucosal surface due to		3. Extravasation of contrast agent into	3
a. injury		a. peritoneal space
b. stricture
3. Malposition of the
a. urinary bladder
b. urethra
4. Foreign body (catheter)		Gastric foreign bodies
		Gastric foreign bodies are noted frequently on the radiograph-
3.1.5.2	Gastrointestinal tract trauma	ic studies. Their identification is dependent on their density
		(Table 3.10), and if surrounding gastric air provides contrast or
Traumatic lesions of the intestinal tract are frequent and are		if ingesta hides the object. If the foreign bodies are obstructive,
generally identified by evaluation of noncontrast radiographs		the clinical importance is greater. Most are only impressive be-
and the identification of peritoneal fluid or air. In patients		cause of their radiographic appearance that is often influenced
with a rupture of the wall of the stomach or bowel, it is pos-		by the patient positioning.
sible that the tear is large enough to permit the release of in-
gesta or the barium contrast agent into the peritoneal cavity;
however, this is an uncommon finding. Often the most im-		Table 3.10: Radiographic density of common gastric foreign bodies
portant radiographic finding is simply a determination of the
		(Cases 3.1, 3.2, 3.5, 3.6, 3.7 & 3.8)
location of the hollow viscus. Displacement of a part of the
		1. Greatest density
gastrointestinal tract is common in hernias and this is readily
determined by identifying the positive contrast within the dis-		a. glass with high lead content
		b. metallic objects
placed stomach or small bowel (Table 3.9).
		c. heavy plastic objects
When used, these contrast studies involve the oral administra-		d. gravel and rocks
		e. large bony fragments
tion of barium sulfate suspension according to the following		2. Medium density
schedule: 8–10 ml/kg bw in small dogs that weigh less than		a. aluminum sheets or strips
10 kg, 5–8 ml/kg bw in medium-sized dogs that weigh be-		b. glass with low lead content
tween 10 –40 kg, and 3–5 ml/kg bw in large dogs that weigh		c. plastic toys
more than 40 kg; and 12–16 ml/kg bw in the cat. These		d. ornaments
dosages are necessary to insure a meal volume that will induce		e. small bone fragments
		3. Lowest density
normal peristalsis. Often, however, the study is made only to
evaluate the location of an organ and the amount of barium		a. ingesta
		b. cloth strips or cloth toys
sulfate meal administered can be less. Radiographs are then
		c. plastic sheets orbags
made shortly after the administration of the meal, but they can
		d. paper
also be made at varying time intervals following administration		e. string or rope

of the contrast agent depending on the information to be gained. In trauma patients, these studies are rarely functional in nature, but are only made to identify the location of the organ and the integrity of its walls.

3.2Case presentations

204 Radiology of Abdominal Trauma

3.2.1Gastric foreign bodies and dilatation

Case 3.1

3

Signalment/History: “Frosty”, a 14-month-old, female DSH cat, was presented because of intermittent vomiting over the previous 1 to 2 months. Vomiting occurred every two to three days and contained bile-stained fluid without food. The use of lamb and turkey diets was unsuccessful in correcting the clinical signs. No radiographic studies had been made.

Radiographic procedure: Abdominal studies were made assuming a possible gastric foreign body.

Radiographic diagnosis: A 2-cm-in-diameter, discoid object with a metallic density and a slightly irregular border lay within the region of the pylorus. The small bowel loops were filled with fluid, but not distended. The colon was gas-filled. No radiographic signs of an obstructive ileus were noted.

Treatment/Management: A partially dissolved copper penny was removed by gastroscopic technique. The pyloric antrum was noted to be highly inflamed. The chronic gastritis resulting from the foreign body was thought to be the cause of the vomiting. “Frosty” improved clinically following removal of the foreign body.

Gastric foreign bodies and dilatation 205

Case 3.2

3

Signalment/History: “Chris” was a 6-year-old, female German Shepherd with a history of depression, vomiting, and hematuria over the previous two days.

Physical examination: The abdomen was tender on physical examination.

Radiographic procedure: The abdomen was radiographed.

Radiographic diagnosis: Radiopaque gastric foreign bodies could be seen with a tissue density suggesting either a metallic, glass-like, or dense plastic composition.

Note the difference in radiographic density of the foreign bodies according to the patient’s position. The lack of contrast between the abdominal organs suggested the presence of peritoneal fluid.

Treatment/Management: “Chris” died from chronic pyelonephritis that had resulted in hypertension, myocardial vascular damage, uremia, widespread mineralization, and parathyroid hyperplasia.

The gastric foreign bodies were glass, but were not thought to have contributed to the production of the clinical signs. Dogs often eat a variety of debris along with their usual diet or sometimes find these objects in a convenient garbage can. In either situation, the resulting radiographic shadows are prominent and may suggest clinical importance. The debris may be obstructive or may be injurious to the mucosal surface; however, if small, they usually pass through the gastrointestinal tract and do not cause more than acute, short-lived clinical problems.

206 Radiology of Abdominal Trauma

Case 3.3

3

Signalment/History: “Bingo” was a 1-year-old, dachshund mixed breed with a history of gagging and choking after eating.

Physical examination: The abdomen was distended on palpation, but was not noticeably painful.

Radiographic procedure: Abdominal radiographs were made.

Radiographic diagnosis: The stomach was distended and filled with ingesta. No evidence of a “pillar” sign or “shelf sign” was present that could have suggested a gastric volvulus/torsion. The pylorus was on the right side in its normal position. The colon was filled with feces that had the same appearance as the gastric contents. The small bowel loops were air filled but not distended.

Treatment/Management: The patient was treated as having marked gastric distention and was given a cleansing enema.

Gastric foreign bodies and dilatation 207

3

Radiographic diagnosis: Radiographs made after the enema showed the stomach to have emptied. Small bowel loops could not be identified. The colon had refilled after the enema.

Treatment/Management: “Bingo” was thought to have had overeaten and returned to normal after the enema.

208 Radiology of Abdominal Trauma

3.2.2Small bowel foreign bodies

Case 3.4

3

Day 1

Signalment/History: “Pepper” was an 8-year-old, female

Terrier mix with a history of vomiting for several days.

Physical examination: Palpation of the abdomen revealed a hard mass in the caudal abdomen the size of a “nut”.

Radiographic procedure: Radiographs were made of the abdomen.

Radiographic diagnosis (day 1): The stomach was distended and filled with air and fluid. The small bowel loops were filled with fluid, although they had a normal diameter. A 2-cm-in-diameter foreign body was located in the midportion of the caudal abdomen. It had a “slit-like” lucency in the center, in addition to a “ring shaped” lucency around its edge.

Small bowel foreign bodies 209

3

Day 2

Radiographic diagnosis (day 2): Studies made one day later again showed a distension of the fluid-filled stomach. The foreign body had the same appearance and was in the same location. A sentinel loop of distended fluid-filled bowel was diagnostic of being secondary to an obstructing foreign body (arrows).

Treatment/Management: The nut was removed from the bowel surgically and “Pepper” recovered quickly. In some societies, it is possible to determine the season of the year and holidays by the character of the foreign bodies found in the bowels of pets.

210 Radiology of Abdominal Trauma

Case 3.5

3

Noncontrast

Signalment/History: “Jenny” was a 1-year-old, female DSH cat who was vomiting. She had been anorectic for several weeks.

Physical examination: A cranial abdominal mass was evident on palpation.

Radiographic procedure: Abdominal radiographs were made, followed by a compression study to further clarify the nature of the suspect mass. Following failure of that procedure to insure a specific diagnosis, a barium sulfate meal was used to further identify the nature of the mass.

Radiographic diagnosis (noncontrast): A poorly marginated mass with a granular consistency was located in the left cranial abdomen, immediately caudal to the liver. Loss of mucosal borders suggested the possibility of focal peritoneal fluid. Both the stomach and small bowel loops were empty. A proximal partially obstructing intestinal lesion was suspected.

The use of a compression device separated the questionable mass from the liver and stomach indicating that it was probably intestinal and was not associated with a focal peritoneal effusion.

Small bowel foreign bodies 211

3

Barium sulfate meal

Radiographic diagnosis (barium sulfate meal): Radiographs made 20 minutes after the administration of a contrast meal showed a lesion in the descending duodenum that was characterized by a marked distention of the bowel with the contrast agent mixing with an intraluminal mass. A portion of the liquid meal passed the lesion and was seen within the distal bowel loops. The contrast study confirmed the presence of a partially obstructing luminal mass within the descending duodenum.

Treatment/Management: A mass of thick paper was removed at surgery and “Jenny” was discharged a happy cat.

Comments: Intraluminal foreign bodies tend to distend the bowel lumen and prevent the contrast meal from outlining a smooth mucosal surface. If some of the meal passes the foreign body, the distal bowel loops will be partially filled. A differential diagnosis radiographically should include an intestinal tumor.