r

‘I

:

.

:

,

#{149}

.

4L

‘:-)‘-‘

v

‘

‘I-

#{149},

J

‘

k

1----

1!

-r

}

l

.p

I,

I

..

J11i

-.

!)

-

.1.’

I 1#{149}

r -

. #{149}11,

T

;.

I

r

American Journal of Roentgenology 1992.158:493-501.

I

Review

;

;

tk

l!II±41Flr

Abdominal

Robert

‘

,-.‘

Article

#{149}

r

Neil T Wolfman

;

E Bechtold

f

L -,T

Trauma:

Evaluation

EricSSch&ling1andJ

Wayne

by CT

Meredith2

CT is the technique of choice for initial examination ot hemoextent of injury to the head, abdomen, chest, pelvis, and dynamically stable patients after blunt abdominal trauma. it is r skeleton [2, 5-1 1 highly sensitive, specific, and accurate for use in detecting the CT examination of the abdomen has largely replaced other presence or absence of injury and defining its extent. Nonoper- : ‘; imaging techniques in the evaluation of hemodynamically ative management of many posttraurnaticinjunes, particularly in stable patients. It is perlormed in patients in whom the abthe liver, spleen, and kidney, is possible in part because of the diagnostic usefulness of CT. CT can be used effectively to visudomen cannot be evaluated adequately by clinical examinaalize the progression of liver and spleen injuries in those patients tion bUS of altered mental status (e.g., ethanol or drug chosen for conservative management. CT helps in treatment abuse, head injury), in those in whom findings on clinical decisions in patients with renal injury by defining the character abdominal examination are equivocal, and in those with sigand extent and distinguishing minor from severe renal trauma. : nificant pelvic fractures or history of multiple operations [2, 5, Posttraumatic injuries to the pancreas, bowel, and mesenterycan 6, 8, 9, 1 2]. CT is not performed in hemodynamically unstable be detected with CT. In these areas, however, signs may be J patients and in patients with obvious signs of peritonitis who subtle and a significant injury may be missed on an initial require immediate surgery For rapid evaluation of the extent examination of abdominal injury diagnostic pentoneal lavage (DPL) can be .

.

].

-

. T

.

.

.

#{149}

-

J

-

I

*j I.

,-

t&fOfTfld

either

immediately

before

or dunng

exploratory

surgery

Trauma is the third leading cause of death in the. United DPL is very sensitive for detecting hemorrhage, is quick States and the leading cause of death in person#{233} less thanTand simple to perform, and does not require sophisticated 40 years old [1 2]. It is currently one of America’s costliest equipment. However, the test cannot differentiate inconsehealth problems [3, 4]. Two important advances in the treatquential from significant bleeding [2, 13], resulting in unnecment of trauma patients in the past decade have been the essary laparotomies in 6-25% of cases [6, 7, 14]. DPL also creation and development of the Emergency Medical Service cannot show the location or extent of injury. Furthermore, it system and the widespread use of CT to examine patients does not show injuries of the retropentoneum, and thus is [2]. The Emergency Medical Service system defines the level T insensitive to trauma to the pancreas, the kidneys, and the of trauma care available at individual hospitals and identifies retroperitoneal portion of the duodenum. Traumatic cannula dedicated trauma centers (levels I and II centers) for desiginsertion, rents in the pentoneal membrane that allow blood nated geographic areas. Referring trauma victims to such from a retropentoneal injury to enter the abdominal cavity, centers for treatment results in reduced morbidity and morand pelvic fractures can result in false-positive examinations tality rates [2]. CT has become an integral part of the clinical [7, 15]. evaluation of traumatized patients because of its high sensiCT has replaced DPL in many centers for the initial evalutivity, specificity, and accuracy in detecting the presence and ation of suspected abdominal injury in stable patients [2, 7, ,

.

.

Received August 15, 1991 ; accepted after revision Octobr 14, 1991 #{149} I Department of Radiology, Bowman Gray School of Medicine, Wake Forest University, Medical Center Blvd., Winston-Salem, requests to N. T. Woffman. 2 Department of Surgery, Bowman Gray Schod of Medicine Wake Forest University, Winston-Salem, NC 27157 AJR 158 493-501

March

1992 0361 -803x/92/1

583-0493

© Amencan -..J

Roentgen

Ray Society

-‘

f

..‘

.

Blunt Upper

ji

IL!!.

.

NC 27157-1088.

Address

.

-‘---p

Pu!

OflO

repnnt

494

WOLFMAN

1 1 12]. Although

many studies

,

value of CT compared

[5, 9, 1 1] have confirmed

with DPL, these

results

the

are somewhat

controversial. Other reports [2, 16-1 9] show CT to be less valuable than DPL, particularly in injuries to the bowel or mesentery, and both CT and DPL may be warranted in such cases. DPL is best performed after CT to avoid interpretive errors because of fluid and free air introduced by the lavage procedure. Important diagnostic information may still be obtamed from CT after DPL by accounting for these factors [18, 20].

The use of CT in the examination of patients with blunt abdominal trauma, along with a trend toward nonoperative

management of many abdominal injuries, has decreased the need for exploratory surgery and reduced the frequency of nontherapeutic

laparotomies

[2, 6, 7, 9]. In fact,

the

trend

toward conservative and nonoperative treatment of many liver, spleen, and kidney injuries is due in part to the ability of CT not only to define injury but also to exclude significant

American Journal of Roentgenology 1992.158:493-501.

injury,

thereby

avoiding

unnecessary

surgery.

The final deci-

sion to operate should be based on CT findings in conjunction with the entire clinical picture and judgment of the attending trauma surgeon [2, 21]. In this article, we review the CT findings in patients with blunt upper abdominal trauma and the impact of these findings on treatment.

ET AL.

AJR:158,

March

1992

IV contrast approximately

material can be given as an initial bolus of 50 ml at a rate of 2-3 mI/sec, followed by a rapid infusion at 1 mI/sec. Alternatively, a single sustained bolus of contrast material at a rate of 1-3 mI/sec may be administered, particularly if dynamic scanning capability is available. The dose is altered for children to 2-3 mI/kg body weight. A mechanical injector is useful for regulating the flow

of contrast

material,

and dynamic

scanning

techniques

are

used to decrease examination time in this group of patients in whom expediency can be critical to successful treatment. Scans are usually taken at 1-cm intervals from the dome of the diaphragm through the abdomen and at 1 .5- to 2.0-cm

intervals

through

the pelvis. Patients

are monitored

through-

out the examination, and emergent resuscitation equipment should be readily available. In addition to soft-tissue window

settings, lung window settings are obtained for evaluation of the lower chest for significant injuries such as pneumothorax, lung parenchymal injuries, or free peritoneal air indicating hollow viscus injury, and bone window settings are used for bony fractures [5]. It is also useful to view images directly on the console video monitor, so that window and level settings can be manipulated to appreciate subtle but potentially significant findings. After the study, oral contrast material can be

withdrawn

from

the

stomach

via

a nasogastric

tube

if

indicated.

Technique Findings and Management Abdominal Trauma CT

Proper technique is critical examination of patients with opacify

bowel,

the patient

for

accurate

blunt

is given

abdominal

abdominal

trauma.

approximately

CT

additional 250 ml just before scanning. To avoid imaging artifacts, the patient’s arms are placed above the abdomen if possible and monitoring devices, tubes, and wires are positioned out of the scan plane. If a nasogastnc tube is in the

stomach, it is partially withdrawn so that the tip is positioned within the distal esophagus and repositioned after the examis completed.

A large field of view

decreases

artifacts

from structures that cannot be removed from the scan field. Restraints or sedation may be necessary to avoid motion artifacts

in patients

unable

to maintain

the proper

in Blunt

To

500 ml of

oral contrast medium (1 -3% solution of diatnzoate sodium or diatnzoate meglumine/diatrizoate sodium) orally or via nasogastric tube approximately 30-45 mm before CT and an

ination

Decisions

position.

Many trauma patients have multiorgan a thorough evaluation of all abdominal ranted in each case.

injuries. Therefore, components is war-

Hemoperitoneum

Hemoperitoneum is easily seen on CT and may be the only or most obvious sign of abdominal injury. Its presence should prompt a thorough search for injury to visceral organs. Hemoperitoneum is differentiated from other fluid because of increased attenuation, averaging 45 H and always greater than 30 H if less than 48 hr old [25]. Hemoperitoneum tends to be identified near the source of bleeding, spreading

Fast scans (60 H) than does free blood [25]. A localized collection of clotted blood, the “sentinel clot,” is an accurate sign of injury to an adjacent organ [28]. This sign may help in detecting subtle bowel, mesentenc, or splenic lesions. The presence of hemoperitoneum on a single CT study does not indicate that active bleeding is present. Jeffrey et al. [29], using dynamic scanning techniques, recently described CT signs of active intraabdominal arterial bleeding. Most frequently seen is a focal high-density area of 80-1 30 H (higher attenuation than free or clotted blood) that is isodense with adjacent major arteries (Fig. 1). Seen less frequently, a diffuse high-density area may simulate extravasation of oral contrast material from perforated bowel, although other signs

ABDOMINAL

TRAUMA

495

of bowel perforation are not present. In most patients with active intraabdominal bleeding, CT is rarely performed because of hemodynamic instability. Occasionally, however, a patient with active abdominal hemorrhage may become hemodynamically stable and then undergo CT. Detection of hemorrhage is then of vital importance, so that proper, potentially life-saving treatment can be instituted quickly. Signs of hypovolemic shock on CT include a small aorta, a collapsed inferior vena cava, marked enhancement of the kidneys, and initially diminished density of spleen compared with liver after contrast enhancement [30-33]. Taylor and Rosenfield [34] described a hypoperfusion complex in children that consists of marked, diffuse dilatation of the intestine by fluid; abnormally intense contrast enhancement of the bowel wall, mesentery, kidneys, and/or pancreas; decreased caliber of the aorta and inferior vena cava; and significant abdominal fluid.

American Journal of Roentgenology 1992.158:493-501.

Spleen

Fig. 1.-Renal fracture in 20year-oid man involved in motor vehicle accident. Enhanced CT scan shows kidney has been completely separated into two perfused poles by a severe laceration. Hematoma is seen between two poles. Focal areas of extremely high attenuation represent active bleeding. Patient died on day of admission.

with subcapsular in 36-year-old woman with hypotension after a fall 1 week before admission. Enhanced CT scan shows an irregular, linear, low-density laceration (ar. row) traversing spleen. Lateral contour of spleen is indented from subcapsular hematoma. Density of clotted blood (arrowhead) is increased when compared with nonclotted portion of hematoma. Large volume of hemoperitoneum in right perihepatic space and surrounding left lobe of liver also is seen. CT findings were confirmed at surgery. A spienectomy was performed, and hemoperitoneum was evacuated. and

Fig. 2.-Splenic penspienic

laceration hematoma

The spleen is the most frequently injured organ in patients with blunt abdominal trauma [5]. CT is extremely sensitive and specific in determining the presence and extent of splenic injury in the traumatized patient, and the CT features of splenic trauma have been well described [2, 35]. Subcapsular hematomas appear as crescentic fluid collections that flatten or indent the splenic margin (Fig. 2). Initially, hematomas may be isodense with splenic parenchyma on contrast-enhanced scans, particularly if adequate volumes of contrast material are not given [20, 35]. Intrasplenic hematomas are seen on CT as rounded low-density areas (Fig. 3). Lacerations appear as linear low-density areas within the spleen (Fig. 2). Multiple lacerations may have the appearance of a fragmented or

Fig. 3.-Injury of liver and spleen in 60-year-old woman after a motor vehicle accident. Enhanced CT scan shows low-density splenic hematoma posteriorly. Spleen also contains multiple lacerations (arrow). Pensplenic and perihepatic blood and liver laceration also are present. Exploratory laparotomy confirmed CT findings.

Fig. 4.-Shattered spleen in 26-year-old woman after motor vehicle accident. Enhanced CT scan shows multiple lacerations and fragmentation of spleen. Large hemoperitoneum also is present, surrounding both spleen and liver. Hemoperitoneum extended into pelvis. Exploratory laparotomy confirmed CT findings.

496

American Journal of Roentgenology 1992.158:493-501.

s

WOLFMAN

shattered spleen (Fig. 4). Unenhancing portions of the spleen should suggest injury or thrombosis of the artery to the affected segment. Disruption of the splenic capsule results in visible hemopentoneum in up to 98% of patients with splenic injury [35]. Pensplenic clot also is associated with splenic injury. Both hemopentoneum and perisplenic clot may be present in cases of splenic injury without evidence of a splenic laceration on CT. Therefore, presence of either should prompt a search for splenic injury. Occasionally, splenic injury may manifest as heterogeneous parenchyma with a mottled irregular enhancement [35]. This finding is almost always associated with pentoneal blood and perisplenic clot and by itself is merely suggestive of splenic injury. The spleen also may transiently appear inhomogeneous during the early capillary phase of a contrast-enhanced dynamic CT study. Certain findings on CT may result in a false-positive diagnosis of splenic injury. Splenic lobulations and congenital clefts, and a prominent left hepatic lobe extending across the midline to lie immediately adjacent to the spleen, may simulate a splenic laceration [36]. Streak and motion artifacts can also result in incorrect diagnoses. The spleen may seem to enlarge on serial CT scans after blunt abdominal trauma [37]. This is a result of initial splenic contraction from adrenergic stimulation at the time of acute injury, which resolves with time and volume replacement. Although rare, delayed splenic rupture has been reported in patients in whom an initial CT scan after injury showed no evidence of splenic abnormality [34, 38-40]. Suboptimal contrast enhancement techniques may be partially responsible for this missed diagnosis [41]. Subtle inhomogeneities of the splenic parenchyma and minimal thickening of the lateroconal fascia and the left anterior renal fascia may be the only signs initially seen in some cases of delayed splenic rupture [40]. King and Shumacker [42] first reported overwhelming sepsis in five children after splenectomy, two of whom died. Other reports followed, confirming the increased risk of late sepsis after splenectomy in both children and adults [43]. This observation has encouraged nonoperative management and splenic salvage procedures in appropriate patients [2, 43-45]. The role of CT in selecting between conservative and operative treatment of splenic injuries remains unclear. Mirvis et al. [46], using a CT classification of four grades of splenic injury, found that although patients with severe splenic injury generally required laparotomy, eight of 23 such patients were treated successfully without surgery, and four of 1 5 patients with minor injury, initially treated conservatively, eventually required celiotomy. Buntain et al. [1 0] had more success in predicting outcome of splenic injury by using a CT classification that, in addition to grading splenic trauma, used modifiers for other intraabdominal and extraabdominal injuries. In their series, only patients with minor injuries were selected for nonoperative management, and all others had laparotomy. Resciniti et al. [47] devised a numeric CT scoring system that graded severity of splenic injury on a scale of 1 -3 and scored 1 point each for the presence of perisplenic fluid, abdominal intraperitoneal fluid, and pelvic intraperitoneal fluid. Questionable observations received 0.5 points. In their series, no

ET AL.

AJR:158,

March

1992

patient with a score lower than 2.5 who was initially managed nonoperatively required celiotomy. Umlas and Cronan [48] applied the grading systems of Buntain et al. and Resciniti et al. to determine whether the outcome of nonsurgical management could be predicted on the basis of CT findings. They found that these systems were not completely reliable. In particular, delayed splenic rupture remains a distinct problem in a small percentage of patients in whom the spleen is normal or shows only a limited injury on the initial CT scan [48, 49]. On the other hand, Brick et al. [21] have shown that moderate or severe splenic injury in children or injury associated with a moderate or large amount of hemopentoneum may be treated successfully without surgery. At this time, although CT is extremely useful in characterizing initial injury and following the evolution of splenic trauma, the final decision on whether to operate or not should be made by the trauma surgeon on the basis of clinical factors and not entirely on the CT findings. Liver The liver is preceded only by the spleen in frequency of injury from abdominal trauma. In 22-61 % of patients with hepatic injuries, significant damage is obvious, and because of shock or peritonitis such patients have immediate surgery without preliminary imaging studies. As with splenic trauma, CT has proved to be highly sensitive, specific, and accurate in defining and characterizing hepatic injury and associated hemopentoneum in hemodynamically stable patients [5, 1 1, 27, 50]. In all reported series, the right hepatic lobe is injured more frequently, probably because of its larger size and proximity to the lower ribs [21 50, 51]. The CT findings in hepatic injury are similar to those seen in the spleen; they include contusions (the mildest injury), subcapsular hematomas, intraparenchymal hematomas, and single or multiple lacerations and fractures through the hepatic parenchyma [7, 27, 50] (Figs. 3 and 5). Lack of enhancement offractures indicates loss of vascular supply with the potential for hepatic necrosis. Periportal tracking (areas of perivascular low-attenuation surrounding peripheral subsegmental portal venous branches) also has been described as a sign of hepatic injury on CT and may be the only finding [51 ] (Fig. 6). Although Macrander et al. [51 ] presume that such tracking is a sign of blood, Cox et al. [52] ascribe the finding to distension of penportal lymphatics because of associated hypotension and subsequent large fluid volume replacement in traumatized patients with no other evidence of abdominal trauma. Hepatic subcapsular and parenchymal gas seen on CT 2-3 days after hepatic trauma may be due to hepatic necrosis and may not be related to infection [53]. The liver has a remarkable ability to heal even after severe injury. Therefore, nonoperative management of such injuries in hemodynamically stable patients is now accepted. Unlike the spleen, the liver does not exhibit delayed rupture. Attempting to define the role of CT in management decisions, Moon and Federle [50] and Meyer et al. [54] reported that limited hepatic injury without evidence of active bleeding and with little or no hemoperitoneum could be managed successfully without surgery. More recently, it has been shown that stable ,

AJR:158,

March

CT

1992

OF

BLUNT

UPPER

ABDOMINAL

497

TRAUMA

Fig. 5.-Liver lacerations in 37-year-old woman injured in motor vehicle accident. Enhanced CT scan shows multiple irregular, low-density linear defects within liver, representing lacerations. Lacerations extend to medial and lateral surfaces of liver. Patient remained hemodynamicaily stable and was treated nonoperatlveiy.

Fig. 6.-Periportal tracking in 16-year-old boy injured In motor vehicle accident. Circumferential low-attenuation areas surround portal venous branches. No other signs of injury were seen on this enhanced CT scan. Patient was treated nonoperatively.

patients with severe hepatic injuries and significant hemoperitoneum also may be treated nonoperatively without significant sequelae [21 27, 55]. Jeffrey [49] states that CT staging of blunt hepatic injuries has little discriminatory value in predicting outcome of stable patients, as nearly all have an ,

American Journal of Roentgenology 1992.158:493-501.

excellent

prognosis.

Other

abdominal

injuries

may,

however,

stress early surgery remaining 5% of renal kidneys, renal pedicle the renal pelvis. These surgery. Of all imaging

to avoid complications [58-60]. The injuries are severe, including shattered injuries, and avulsion and laceration of catastrophic injuries require immediate

techniques,

CT most

accurately

depicts

the

require laparotomy. Management decisions in the setting of hepatic injury should be based on clinical factors, and CT should be used to depict the injury and detect healing and resorption of

character and extent of renal injury, best displays penrenal hematomas and extravasation of urine, best distinguishes between the categories of renal trauma, and, therefore, is most useful in case management [57, 58, 61 62]. CT also

hemoperitoneum. Peritoneal blood is normally resorbed and therefore significantly reduced or absent within 1 week on

detects associated injuries within retroperitoneum that may influence

follow-up CT scans [27]. Otherwise, should be suspected. Subcapsular

patient with a suspected isolated renal injury, excretory urography will usually suffice as an initial examination [58, 62, 63]. Normal findings on excretory urography exclude significant renal injury. However, evidence of significant renal trauma on excretory urography often requires further evalu-

solves

within

6-8

weeks

[56].

continued hematoma

lntraparenchymal

hemorrhage usually rehematomas

heal much more slowly and may persist for several years, as bile in the hematoma delays clot resorption and adversely affects parenchymal healing [56]. Persistent intraparenchymal hematoma appears as a collection with a high attenuation (30-50 H). A water-density posttraumatic cyst or biloma may result. Lacerations, conversely, appear to heal more rapidly, and significant healing is seen on serial CT examinations over a 3-week period [27]. Clearly, any patient selected for con-

servative therapy requires continued hemodynamic monitoring and laboratory assessment; transfusion as needed; and the availability of nursing, surgical, and imaging facilities if hemodynamic

instability

develops

[27, 55].

,

ation with

renal injuries (75-85%) are minor and include contusions, intrarenal hematomas, small subcapsular hematomas, small lacerations that do not communicate with the collecting systern, and small segmental infarcts. Patients are usually hemodynamically

stable,

have

microscopic

hematuria,

and

are

treated conservatively. Intermediate injuries, which account for approximately 1 0% of renal trauma, include deep lacerations that communicate with the collecting system and result in urine extravasation. controversial; some

less severe

bleeding

Treatment of such injuries is somewhat advocate conservative management un-

or clinical deterioration

ensues;

others

of renal injuries on enhanced CT has been [57-60, 62]. Contusion, the mildest renal

injury, results in edema and extravasation of small amounts of blood and urine into the interstitial space [58, 62]. Contu-

sion may be subtle When

present,

and missed

it appears

on contrast-enhanced

as poorly

defined

CT.

areas

of de-

creased enhancement. Lang et al. [62] described the appearance of a small collection of contrast medium in the renal interstitium on delayed scans as a sign of contusion. Contuusually

Intrarenal

Renal injuries after blunt abdominal trauma can be categorized as minor, intermediate, and severe [57-60]. Most

cavity and In a stable

CT.

The appearance well documented

sions Kidney

the peritoneal management.

hancement Subcapsular

resolve

within

1 week.

hematomas

appear as areas of decreased enmay be poorly defined or well marginated.

that hematomas

are confined

by the renal

capsule,

are often lenticular, and may flatten the renal border. An apparent low-attenuation region around the surface of the kidney

may be caused

by respiratory

motion

during

the scan

and can result in a false diagnosis of subcapsular hematoma [60]. In such cases, a similar appearance is noted anterior to the abdominal wall. Lacerations appear as focal parenchymal injuries with decreased enhancement. If they involve the collecting system, contrast-laden urine extravasates and is easily seen on CT (Fig. 7). A significant perirenal hematoma is usually present with severe lacerations. Because of fascial fusions in the retroperitoneum,

hematomas

due to or associated

with

renal

WOLFMAN

498

American Journal of Roentgenology 1992.158:493-501.

Fig. 7.-Renal laceration extending Into collecting system in 37-year-old man Injured In motor vehicle accident Enhanced CT scan shows contrast cxtravasatlon (arrow). Posterior segment of kidney is not enhanced, denoting loss of vascular supply. Perirenal hematoma alsols seen. Nephrectomy was performed

(Fig. 1). Lacerations

usually

occur

par-

allel to the main vascular parenchymal enhancement erated

fragments

structures, preserving them, and is observed. The margins of lacmay have an inhomogeneous, mottled ap-

pearance, possibly the result of vasospasm. The shattered kidney contains multiple lacerations, some of which may shear across

vascular

planes

and

produce

devascularized

ments with nonenhancing parenchyma. the hilar lip of the kidney may appear its characteristic confusion. A segmental

posterolateral

AL.

location

frag-

A section through as a fracture, but should

prevent

patients

infarct

may

result

from

injury

intrarenal or polar arterial branch [60] and appears as a wedge-shaped or hemispheric area of nonperfusion with the apex pointing toward the renal hilum (Fig. 8). A thin enhancing nm may be seen [62]. Eventually a deep scar forms in the area of infarction.

1992

Fig. 9-Pancreatic laceration in 29-year-old man who fell 9 m from a tree. Enhanced CT scan shows site of laceration (arrow) at junction of body and tail of pancreas. Associated peripancreatic fluid and thickening of left anterior pararenal fascia also are noted. Splenic laceration with a segmental perfusion defect, seen anteriorly in spleen on this image, was due to loss of vascular supply. CT findings were confirmed at exploratory laparotomy.

in their

series.

Lang

et al. [62],

on the other

hand,

patients

in their

series.

Injury

to the renal

vein

after

blunt

trauma is missed more often than injury to the artery; in addition to lack of enhancement, the kidney may appear enlarged, the rim enhancement may be thicker, and thrombus in the vein may be seen [58]. Pancreas

Pancreatic injuries, fractures, contusions,

including pancreatic duct and traumatic pancreatitis,

3-1 2% of all abdominal

to an

March

found CT less reliable in the detection of trauma to the renal artery, as the diagnosis was missed on CT in five of seven

clinically renal

AJR:158,

Fig. 8.-Left renal pedicle injury in 36-year-old woman after motorcycle accident CT scan was obtamed after perltoneal lavage and excretory urography. Left kidney does not enhance because of renal pedicle injury. Perlrenal and anterior pararenal hematomas are noted also. Typical appearance of wedgeshaped perfusion defect representing segmental renal infarct (arrow) is seen in right kidney. Li vertebral burst fracture also is present with surrounding hematoma. An avulsed left renal artery was found at surgery.

tr&ima tend not to cross the midline; the presence of such a hematoma should prompt a search for injury to the aorta, its branches, or other midline structures [57]. Lacerations that completely transect the kidney into two separate poles are often called fractures

ET

20%

important,

of cases

complications curling

injuries from blunt trauma.

however,

because

of pancreatic

trauma,

(pseudocyst,

abscess,

pancreatitis,

disruption, represent

and fistulae)

death

and major

in 16-

posttraumatic

hemorrhage,

occur

They are

occurs

acute

in one of three

re-

survi-

vors [1 7, 65, 66]. Delay in diagnosis leads to an increase in the mortality and morbidity rate. The typical clinical findings of upper abdominal pain, leukocytosis, and increased serum

Laceration of the renal pelvis or avulsion of the ureteropelvic causes extravasation of contrast-laden urine. Extravasation without evident renal injury should raise suspicion of

amylase may not be apparent for one or more days after acute pancreatic trauma. In addition, an increase in the serum

such injuries of the renal pelvis [60].

injury [67]. Pancreatic

junction

In many cases

an injury of the renal pedicle

arterial or venous occlusion CT because the kidney does rim of enhancement may be blood flow from the capsular

resulting

in

can be clearly documented on not enhance (Fig. 8). A cortical present as a result of collateral arteries. An abrupt cutoff of the

amylase

level after trauma may be present injury

may

be difficult

without

to diagnose

pancreatic on CT [17,

Little evidence of pancreatic injury may appear on CT examinations performed soon after the traumatic event [65]. Pancreatic duct disruption is the most significant pancreatic 65].

injury.

Although

this abnormality cannot be seen directly on injury to the pancreas may be detected. Fracture of the pancreas, depicted as a clear separation or low-density line through the long axis, occurs most commonly

associated

contrast-enhanced renal artery is seen occasionally [64]. The reliability of CT in detecting injuries of the renal pedicle is in dispute. Sclafani et a]. [57] consider CT the method of choice

CT,

and confirmatory angiography unnecessary. Lupetin et al. [64], using CT, diagnosed renal artery occlusion in all seven

in the neck of the pancreas as a result of compression of the organ against the spine [67] (Fig. 9). Thickening of the left

AJR:158,

March

anterior

CT

1992

renal

fascia,

although

not

OF

specific

BLUNT

for

UPPER

enlargement of the organ, areas of decreased attenuation, and peripancreatic edema and fluid collections [1 7, 65, 67]. If the possibility of pancreatic trauma persists despite initially normal CT findings, a second CT examination in 1 2-24 hr may be warranted, because signs of injury can be delayed. ERCP, which directly visualizes the pancreatic duct, may also be necessary for further evaluation when CT findings are equivocal or CT is technically inadequate [65]. Immediate

is the

recommended

treatment

for

pancreatic

fracture.

Bowel

American Journal of Roentgenology 1992.158:493-501.

Bowel and mesentery injuries are reported to occur in 5% of blunt trauma cases [68]. As these injuries are most commonly seen in restrained motor vehicle accident victims, the may rise as seat belt usage is important. In patients with

area, anterior to the liver. Extraluminal within the leaves of the mesentery or in the retropentoneum, particularly in the anterior pararenal space. Occasionally, pneumopentoneum results from pneuair also may be present

momediastinum, pneumothorax, bladder rupture, or previous peritoneal lavage and is not related to bowel trauma [17, 70]. Extravasation of oral contrast material from the bowel

lumen is a specific sign of bowel perforation (Fig. 1 1). Unfortunately, its presence is shown on CT in only a minority of cases. lntraabdominal fluid, although seen in nearly all cases of bowel or mesentenc injury, is not a specific indicator. Moderate or large amounts of fluid are associated significant bowel or mesenteric trauma. If no associated

increases duodenal

[1 6]. Early perforation,

uation

mesentenc

hematoma

bowel tion. Therefore,

its absence

Although

Rizzo

Unfortunately,

clinical

injury include material,

extralu-

pentoneal

or

retropentoneal fluid, thickened bowel wall, high-density clot (sentinel clot) adjacent to the involved bowel, and focal mesentenc infiltration [1 6, 68]. Free air in either the peritoneal cavity

or the retroperitoneum

duodenum,

small bowel,

injuries,

not

exclude

bowel

may be difficult

high sensitivity

other authors

can

injury

in detecting

indicate that this

with CT [2, 1 7, 33, 72]. This difficulty

may be due in part to the subtlety

minal air, extravasation

of oral contrast

signs

does

et al. [68] report

diagnosis

69].

initially may be subtle or absent. CT signs of bowel and mesentenc

hematoma

[68].

mortality

[68,

or intramural

the site of injury [28, 71] (Fig. 1OB). Thickened is seen in about 75% of cases with transmural lacera-

bowel and mesentery

of 65%

with solid

help localize

surgery performed within 24 hr of injury has a 5% mortality rate, whereas delayed diagnosis and treatment leads to a rate

499

visceral injury is noted, bowel or mesentenc injury should be suspected [1 6, 68]. Focal mesenteric infiltration is also a frequently seen but nonspecific sign. A localized high-atten-

and Mesentery

incidence diagnosis

TRAUMA

the subdiaphragmatic

pancreatic

injury, is frequently present and should raise the possibility of pancreatic injury [65]. Other signs include focal or diffuse

surgery

ABDOMINAL

of the findings

and the fact

that presentation of signs and symptoms may be delayed. The initial CT examination may be done before the clinical signs are manifest [1 7, 33, 68]. The coordinated use of CT and pentoneal lavage for diagnosis of bowel and mesenteric injuries has been suggested [1 6, 18].

from injury to the retroperitoneal

or colon is a relatively

specific

sign

of bowel perforation but is seen in only half of cases [68, 69] (Fig. 1 OA). The volume of air may be quite small and subtle. Wide window or lung settings will aid in detection. The most common location in which to detect free intraperitoneal air is

Miscellaneous

Abdominal

Trauma

Gallbladder injury after blunt abdominal trauma is uncommon, occurring in 2-3% of cases [73, 74]. Laceration or perforation,

complete

avulsion,

or intramural

;___%

-V.

Fig. 10.-Perforated jejunum in 37-year-old man injured in motor vehicle accident A, Enhanced CT scan shows free intraperitoneal air due to jejunal perforation anterior to liver. Wide window settings are used to accentuate display of free air. B, CT scan at level caudal to A shows localized high-attenuation hematoma adjacent to mildly dilated loop of bowel denoting site of Injury. Free intraperitoneal blood also is seen in both right and left paracolic gutters. Exploratory laparotomy revealed a perforated jejunum, torn mesentery, and ischemlc lleum.

--

, #{149}

contusion

can

.

Fig. 11.-Perforated duodenum in 38-year-old man hit by a train. CT scan shows extravasation of oral contrast material from duodenum at site of injury (arrow). Free perltoneal fluid is noted in Morison pouch. Diffuse mesenteric edema also is present CTflndingswere confirmed at exploratory laparotomy.

500

WOLFMAN

Fig. 12.-Traumatic rupture of left hemidiaphragm in 20-year-old man injured in motor vehicle accident CT scan shows that stomach, containing oral contrast medium, has herniated through dlaphragmatic rupture and lies within thoracic cavity. Left hemidiaphragmatic rupture was confirmed at exploratory laparotomy.

American Journal of Roentgenology 1992.158:493-501.

occur.

On CT, the gallbladder

orrhage

with associated

associated

with

may contain

peritoneal

bile leakage

also

high-density

blood; may

hem-

low-density

be present

fluid

[73,

74].

Hemobilia is likely if high-attenuation material is seen in the gallbladder, and other causes of increased density, such as stones, contrast material, and milk-of-calcium bile, can be excluded

patients

[75].

after

Diaphragmatic

blunt

rupture

abdominal

trauma

occurs

in 1-2%

and almost

of

always

affects the left side [76, 77]. This injury is difficult to diagnose with any imaging technique and is often missed on CT [76].

Hemiation of abdominal contents through be seen occasionally [77] (Fig. 12). Traumatic

patients

adrenal

hemorrhage

after severe trauma

occurs

the diaphragm in up to 25%

may of

[78, 79]. In 85% of cases hem-

orrhage is right-sided and in 20% of cases it is bilateral. On CT, adrenal hemorrhage appears as a hyperdense mass (5075 H) with streaky infiltration into the penadrenal fat and

thickening at the adjacent malities in the subcutaneous site of trauma

diaphragmatic crus [78]. Abnorfat of the abdominal wall at the

also may be seen [79].

REFERENCES 1 . U.S. Bureau of the Census. Statistical abstract of the United States: 1990, 1 10th ed. Washington, DC: U.S. Government Printing Office, 1990: 78-81,85 2. MCCOrt JJ. Caring for the major trauma victim: the role for radiology. Radiology 1987;163: 1-9 3. MacKenzie EJ, Morris JA Jr, Smith GS, Fahey M. Acute hospital costs of trauma in the United States: implications for regionalized systems of care. J Trauma 1990;30:1096-1103 4. Harlan LC, Harlan WR, Parsons PE. The economic impact of injuries: a major source of medical costs. Am J Public Health 1990;80:453-459 5. Federle MP. CT of abdominal trauma. In: Federle MP, Brant-Zawadzki M, eds. Computed tomography in the evaluation of trauma, 2nd ed. Baltimore: Williams & Wilkins, 1986:191-273 6. Peitzman AB, Makaroun MS, Slasky BS, Ritter P. Prospective study of computed tomography in initial management of blunt abdominal trauma. J Trauma 1986;26:585-592 7. Federle MP, Crass RA, Jeffrey RB, Trunkey DD. Computed tomography in blunt abdominal trauma. Arch Surg 1982;117:645-650 8. Kaufman RA, Towbin R, Babcock DS, et al. Upper abdominal trauma in children: imaging evaluation. AJR 1984;142:449-460

ET

AL.

AJR:158,

March

1992

9. Wing VW, Federle MP, Morris JA Jr, Jeffrey RB, Bluth R. The clinical impact of CT for blunt abdominal trauma. AJR 1985;1 45:1191-1194 10. Buntain WL, Gould HR, Maull KI. Predictability of splenic salvage by computed tomography. J Trauma 1988;28:24-34 1 1 . Goldstein AS, Sclafani SJA, Kupferstein NH, et al. The diagnostic superiority of computerized tomography. J Trauma 1985;25:938-946 12. Federle MP, Goldberg HI, Kaiser JA, Moss AA, Jeffrey RB Jr, Mall JC. Evaluation of abdominal trauma by computed tomography. Radiology 1981;138:637-644 13. Gomez GA, Alvarez R, Plasencia G, et al. Diagnostic peritoneal lavage in the management of blunt abdominal trauma: a reassessment. J Trauma 1987;27: 1-5 14. Powell RW, Green JB, Ochsner MG, BarttelbOrt SW, Shackford SR. Sise MJ. Peritoneal lavage in pediatric patients sustaining blunt abdominal trauma: a reappraisal. J Trauma 1987;27 :6-10 15. Hubbard SG, Bivins BA, Sachatello CR, Griffen WO Jr. Diagnostic errors with peritoneal lavage in patients with pelvic fractures. Arch Surg 1979;1 14:844-846 16. Hayes CW, Conway WF, Walsh JW, Coppage L, Gervin AS. Seat belt injuries: radiologic findings and clinical correlation. RadioGraphics 1991;1 1:23-26 17. Cook DE, Walsh JW, Vick CW, Brewer WH. Upper abdominal trauma: pitfalls in CT diagnosis. Radiology 1986;159:65-69 18. Keamey PA Jr, Vahey 7, Burney RE, Glazer G. Computed tomography and diagnostic peritoneal lavage in blunt abdominal trauma: their combined role. Arch Surg 1989;124:344-347 19. Marx JA, Moore EE, Jorden RC, Eule J Jr. Limitations of computed tomography in the evaluation of acute abdominal trauma: a prospective comparison with diagnostic peritoneal lavage. J Trauma i985;25:933-937 20. Kane NM, Dorfman GS, Cronan JJ. Efficacy of CT followiog peritoneal lavage in abdominal trauma. J Comput Assist Tomogr 1987;1 1:998-1002 21 . Brick SH, Taylor GA, Potter BM, Eichelberger MR. Hepatic and splenic injury in children: role of CT in the decision for laparotomy. Radiology 1987;165:643-646 22. Kelly J, Raptopoulos v, Davidoff A, Waite R, Norton P. The value of noncontrastenhanced CT in blunt abdominal trauma. AiR 1989;152:41-46 23. Mindell HJ. On the value of non-contrast.enhanced CT in blunt abdominal trauma. MR 1989;152:47-48 24. Taylor GA, Guion CJ, Potter BM, Eichelberger MR. CT of blunt abdominal trauma in children. AJR 1989;153:555-559 25. Federle MP, Jeffrey RB Jr. Hemoperitoneum studied by computed tomography. Radiology 1983;148:187-192 26. Meyers MA. intraperitoneal spread of infections. In: Meyers MA. Dynamic radiology of the abdomen: normal and pathologic anatomy, 3rd ed. New York: Springer-Verlag, 1988:49-89 27. Foley WD, Cates JO, Keliman GM, et al. Treatment ofblunt hepatic injuries: role of CT. Radiology 1987;164:635-638 28. Orwig 0, Federle MP. Localized clotted blood as evidence of visceral trauma on CT: the sentinel clot sign. AJR 1989;153:747-749 29. Jeffrey RB Jr, Cardoza JO, Olcott EW. Oetection of active intraabdominal arterial hemorrhage: value of dynamic contrast-enhanced CT. AiR 1991;156:725-729 30. Shin MS, Borland LL, Ho K-J. Small aorta: CT detection and clinical significance. J Comput Assist Tomogr 1990;14: 102-1 03 31 . Jeffrey RB Jr. Federle MP. The collapsed inferior vena cava: CT evidence of hypovolemia. AiR 1988:150:431-432 32. Sclafani SJA, Becker JA. Radiologic diagnosis of renal trauma. UrolRadiol 1985:7:192-200 33. Berland LL, VanDyke JA. Decreased splenic enhancement on CT in traumatized hypotensive patients. Radiology 1985:156:469-471 34. Taylor CR, Rosenfield AT. Umitations of computed tomography in the recognition of delayed splenic rupture. J Comput Assist Tomogr 1984;8: 1205-1 207 35. Federle MP, Gnffiths B, Minagi H, Jeffrey RB Jr. Splenic trauma: evaluation with CT. Radiology 1987:162:69-71 36. Jeffrey RB, Laing FC, Federle MP, Goodman PC. Computed tomography of splenic trauma. Radiology 1981:141:729-732 37. Goodman LA, Aprahamian C. Changes in splenic size after abdominal trauma. Radiology 1990:176:629-632 38. Pappas 0, Mirvis SE, Crepps JT. Splenic trauma: false-negative CT diagnosis in cases of delayed rupture. AiR 1987:149:727-728 39. Fagelman 0, Hertz MA, Ross AS. Delayed development of splenic subcap-

AJR:158,

40. 41

.

42. 43. 44.

45,

46.

47.

American Journal of Roentgenology 1992.158:493-501.

48.

49. 50. 51

52. 53.

54.

55.

56. 57. 58. 59.

.

March

1992

CT

OF

BLUNT

UPPER

sular hematoma: CT evaluation. J ComputA.ssist Tomogr 1985:9:815-816 Sutton CS, Haaga JR. CT evaluation of limited splenic trauma. J comput Assist Tomogr 1987;11:167-169 Conrad MR. SpIeniC trauma: false-negative CT diagnosis in cases of delayed rupture (letter). AiR 1988;151 :200 King H, Shumacker HB Jr. SpleniC studies. I. Susceptibility to infection after splenectomy performed in infancy. Ann Surg 1952;136:239-242 Elmore JA, Clark OE, Isler RJ, Homer WA. Selective nonoperative management of blunt splenic trauma in adults. Arch Surg 1989:124:581-586 Em SH, Shandling B, Simpson JS, Stephens CA. Nonoperative managemont of traumatized spleen in children: how and why. J Pediatr Surg 1978:13:117-119 Zucker K, Browns K, Rossman 0, Hemingway 0, Salk A. Nonoperative management of splenic trauma: conservative or radical treatment? Arch Surg 1984;1 19:400-404 Mirvis SE, Whitley NO, Gens OR. Blunt splenic trauma in adults: CT-based classification and correlation with prognosis and treatment. Radiology 1989;171 :33-39 Resciniti A, Fink MP, Raptopoulos V. Oavidoff A, Silva WE. Nonoperative treatment of adult splenic trauma: development of a computed tomographic scoring system that detects appropriate candidates for expectant management. J Trauma 1988:128:828-831 Umlas S-L, Cronan JJ. SpleniC trauma: can CT grading systems enable prediction of successful nonsurgical treatment? Radiology 1991:178: 481-487 Jeffrey RB Jr. CT diagnosis of blunt hepatic and splenic injuries: a look to the future (editorial). Radiology 1989;171 :17-18 Moon KL Jr. Federle MP. Computed tomography in hepatic trauma. AiR 1983:141:309-314 Macrancor sJ, Lawson TL, Foley WO, Oodds WJ, Erickson SJ, Ouiroz FA. Penportal tracking in hepatic trauma: CT features. J comput Assist Tomogr 1989:13:952-957 Cox JF, Friedman AC, Radecki P0, Lev-Toaft AS, Caroline OF. Penportal lymphadema in trauma patients. AiR 1990:154:1124-1125 Abramson SJ, Borden WE, Kaufman RA, Ruzal-Shapiro C. Hepatic parenchymal and subcapsular gas after hepatic laceration caused by blunt abdominal trauma. MR 1989:153:1031-1032 Meyer AA, Crass RA, Urn AC Jr, Jeffrey RB, Federle MP, Trunkey 00. Selective nonoperative management of blunt liver injury using computed tomography. Arch Surg 1985;120:550-554 Mirvis SE, Whitley NO, Valnwrsght JR, Gens OR. Blunt hepatic trauma in adults: CT-based classification and correlation with prognosis and treatmont. Radiology 1989:171:27-32 Savolaine ER, Grecos GP, Howard J, White P. Evolution of CT findings in hepatic hematoma. J Comput Assist Tomogr 1985:9:1090-1096 Sclafani 5JA, Becker JA, Shaftan GVV, et al. Strategies for the radiologic management of genitounnary trauma. Urol Radiol 1985;7:231-244 Pollack HM, Wein AJ. Imaging of renal trauma. Radiology 1989:172: 297-308 Foderle MP, Kaiser JA, McAninch JW, Jeffrey RB, Mall JC. The role of

ABDOMINAL

.

62.

63.

64. 65. 66. 67. 68.

69. 70.

71

72. 73.

74.

501

computed tomography in renal trauma. Radiology 1981:141:455-460 Fanney OR, Casillas J, Murphy BJ. CT in the diagnosis of renal trauma. RadioGraphics 1990:10:29-40

60. 61

TRAUMA

.

Sandier injuries.

CM, Toombs BO. Computed tomographic Radiology 1981;141 :461-466

evaluation

of blunt renal

Lang EK, Sullivan J, Frentz G. Renal trauma: radiological studies. Comparison of urography, computed tomography, angiography, and radionuclide studies. Radiology 1985:154:1-6 Kisa E, Schenk WG lii. Indications for emergency intravenous pyelography (IVP) in blunt abdominal trauma: a reappraisal. J Trauma 1986:26: 1086-1089 Lupetin AR. Mainwanng BL, Daffner RH. CT diagnosis ofrenal artery injury caused by blunt abdominal trauma. AiR 1989:153:1065-1068 Jeffrey RB Jr, Federle MP. Crass RA. Computed tomography of pancreatic trauma. Radiology 1983:147:491-494 Carr NO. Calms Si, Lees WA, Russell RCG. Late complications of pancreatic trauma. Br J Surg 1989;76: 1244-1 246 Oodds WJ, Taylor AJ, Erickson SJ, Lawson TL. Traumatic fracture of the pancreas: CT characteristics. J Comput Assist Tomogr 1990:14:375-378 Rizzo MJ, Federle MP, Griffiths BG. Bowel and mesenteric injury following blunt abdominal trauma: evaluation with CT. Radiology 1989:173: 143-148 Glazer GM, Buy JN, Moss AA, Goldberg Hi, Federle MP. CT detection of duodenal perforation. AiR 1981:137:333-336 Bulas 01, Taylor GA, Eichelberger MR. The value of CT in detecting bowel perforation in children after blunt abdominal trauma. AiR 1989:153: 561-564 Plojoux 0, Hauser H, Wettstein P. Computed tomography of intramural hematoma of the small intestine: a report of 3 cases. Radiology 1982:144:559-561 Sherck JP, Oakes 00. Intestinal injuries missed by computed tomography. J Trauma 1990:30:1-7 Jeffrey RB Jr. Fedetle MP, Laing FC, Wing VW. COmputed tomography of blunt trauma to the gallbladder. J Comput Assist Tomogr 1986:10: 756-758 Gottesman L, Marks RA, Khoury PT, Moailem AG, Wichem WA Jr. Oiagnosis of isolated perforation of the gallbladder following blunt trauma

using sonography and CT scan. J Trauma 1984;24:280-281 Krudy AG, Doppman JL, Bissonette MB, Girton M. Hemobiiia: computed tomographic diagnosis. Radiology 1983:148:785-789 76. Gelman A, Mirvis SE, Gens 0. Diaphragmatic rupture due to blunt trauma: sensitivity of plaln chest radiographs. AiR 1991;156:51-57 77. Heiberg E, Woiverson MK, Hurd RN, Jagannadharao B, Sundaram M. CT recognition of traumatic rupture of the diaphragm. AJR 1980:135: 369-372 78. Wiims GE, Marchal GJF, Baert AL, et al. CT and ultrasound features of post-traumatic adrenal hemorrhage. J Comput Assist Tomogr 1987;1 1: 112-115 79. Murphy BJ, Casilias J, Ynzarry JM. Traumatic adrenal hemorrhage: radiologic findings. Radiology 1988;169:701-703 75.