Lawrence

R. Goodman,

MD

#{149} Charles

Aprahamian,

MD

Changes In Splenic Size after Abdominal Trauma’ After spleen

blunt abdominal trauma, the often increases in volume on serial computed tomographic (CT) scans. To determine the frequency and significance of such enlargement, the authors performed a retrospective analysis of 44 hemodynamically stable patients who had experienced recent blunt abdominal trauma. The severity of splenic, hepatic, or other visceral injuries seen on each CT scan was numerically scored, and the amount of intraperitoneal fluid was assessed. Twentyfive patients (57%) had over 10% enlargement (average enlargement, 56%) on follow-up scans. Increasing volume did not correlate with clinical deterioration or the need for splenectomy. It did correlate modestly with the amount of blood in the penitoneum on CT scans, the number of units of blood transfused, and two clinical indexes of systemic trauma. Therefore, an enlarging spleen is not a CT indicator of a deteriorating clinical condition. This phenomenon is most likely due to marked adrenergic stimulation after injury and changing fluid volumes. Index terms: men, injuries, 775.412,

Spleen, 775.412 Trauma, Radiology

From

Abdomen,

CT, 78.1211 #{149} Abdo78.41 1, 78.412 #{149} Hemorrhage,

78.412 #{149} Hemorrhage, CT, 775.1211 #{149}Spleen, Spleen, 775.41,

#{149}

1990;

the

injuries, 78.41

CT, 775.1211

hemorrhage, 775.411, 775.412

176:629-632

Department

of Radiology

(L.R.G.)

and Section of Trauma (CA.), Medical College

and Emergency Surgery of Wisconsin, 8700 W Milwaukee, WI 53226. From

Wisconsin Aye, the 1989 RSNA scientific assembly. Received November 6, 1989; revision requested December 28; revision received March 19, 1990; accepted April 12. Address reprint requests to

L.R.G. 0RSNA,

1990

I

hemorrhage remains a leading cause of death aften blunt abdominal trauma. Injuries of the spleen and liver have traditionally been managed with early diagnosis, based on physical examination and penitoneal lavage, and treatment with laparotomy, splenectomy, and surgical repair of liver lacerations. Concern for postsplenectomy sepsis and the ability of computed tomography (CT) to enable diagnosis of both the site(s) of injury and the amount of intrapenitoneal hemorrhage has led to the use of selective nonoperative management of hemodynamically stable patients with injuries of the liver and spleen (1-6). At our institution, patients with liver, spleen, and renal injuries who are clinically stable are managed with careful clinical monitoring and serial CT scans, obtained approximately 3 days and 7 days after injury. Surgery, interventional nadiologic procedures, or both are used only if the patient’s clinical condition worsens or serial CT scans show evidence of a worsening intraabdominal injury (7). Recently, at our institution, a hemodynamically stable 23-year-old woman injured in an automobile accident underwent CT at admission, and her condition was diagnosed as minor splenic laceration without significant intraabdominal hemorrhage. She was managed nonopenatively and underwent follow-up abdominal CT at 3 days and 8 days. The scans demonstrated no regression of the laceration and progressive increase in splenic volume, from 295 to 363 to 425 cm3, a 44% increase. Because of the persistent laceration and the dramatic increase in splenic volume, the patient’s abdomen was explored at surgery. A normal-appearing, nonbleeding spleen with a stable laceration was identified. No repair was necessary. This experience prompted us to examine the significance of posttrauNTRAABDOMINAL

matic tected tively volume

changes in splenic volume dewith serial CT. We netnospecstudied changes in splenic in patients undergoing serial

CT as part of their nonoperative management. These findings were then correlated with other CT evidence of blunt trauma, various clinical parameters, and clinical treatment.

MATERIALS

AND

METHODS

During a 36-month period cember 3i, 1988, 51 patients abdominal

operative serial

cluded

trauma

were

management CT examinations. in our study

namicaily lus dynamic

at least

one

tion

within

7 days.

treated

with

non-

and underwent Patients were inif they were hemody-

stable and abdominal

and

ending Dewith blunt

had

additional The

undergone

bo-

CT at admission CT examinaindex

patient

and

six other patients, whose CT examinations precluded accurate measurement of splenic volume, were excluded from furthen review. Thus, 44 patients were included in this study. Patients were scanned with a GE 9800 scanner (GE Medical Systems, Milwaukee); a dynamic technique with intravenous bolus injection ing

was used whenever possible 10-mm sections, a 2-second

(includscantime,

and

a 6-second

i00-i50

mL

of 60%

interscan

iothalamate

delay; megiumine

(Con-

ray 60; Mallinckrodt Medical, St Louis) was injected for 2 minutes, with a 45-second interval between the start of injection and the first scan). Some variation in injection

rate

was

noted

from

patient

to

patient. All images were made at 50 HU and with a window of 350 HU. The area of each axial scan of the spleen was determined on the monitor by tracing the margin of the spleen with a builtin

cursor

controlled

by

a track

ball.

Sub-

capsular hematomas were not included in the splenic area measurement, but intrasplenic hematomas were included. Section volumes were then calculated by multiplying by section thickness (1 cm)

Abbreviations: ISS = injury ma scone.

GCS = Glasgow severity score, RTS

=

coma scone, revised trau-

629

Table 1 CT Trauma

Table 2 Population

Score

Site

Characteristics No Change

Score

Finding

Factor

Laceration (linear defect) Fracture (thick, irregular

Spleen

Liver

Fracture

spleen (linear

No. of patients Age (y)(mean) Malesubjects Days in intensive

2

organ Abdomen

Note-Total * Per organ

3

Surgery

1

Abdominal Transfusion

Blood Perisplenic subcapsular Perihepatic Left flank Right flank

tions size.

was

also

between

and

1

Spleen Blood Other

1 1

changing

combina-

spleen

Our 44 patients included 29 male and 15 female subjects (Table 2). The average age was 28 years (range, 5-78 #{149} Radiology

no. of units)

25 27

44 28

17(68)

29(66)

4.2

4.5

17(68)

23(52)

4(9) 1.9

4(16) 2.7

0.9

(mean)

12.6 11.2 18.0

(mean) Liver laceration

RESULTS

630

(mean)

GCS* RTS ISS

laceration

Total Note.-Numbers *

performed

unit

0

(mean

1

total CT trauma score. injured (eg, kidney, pancreas).

of variables

Total

II)

11.6 10.4 22.8

20.7

12.0 10.7

0.8 1.2 1.1 0.01

1.5 0.4 1.5 0

1.2 0.8 1.3 0

3.2

3.5

3.3

CT score or

and were added to determine the total splenic volume. The validity and reproducibility of this method were previously documented (8-10). The percentage change in splenic volume was calculated as follows: [(volume scan 2 - volume scan 1) X iOO]/volume scan 1. The severity of splenic, hepatic, or other visceral injuries seen on each CT scan was numenicaily scored, and the amount of intraperitoneal fluid (presumably blood, because patients did not undergo lavage) was assessed (Table 1). A combined CT trauma score was assigned to each patient on the basis of severity of organ injury or injuries and the amount of blood in the abdomen. This score was a modification of several previously published grading systems (2-4). The CT scan reader (L.R.G.) knew the nature of the study but not the specifics of the clinical history or subsequent treatment. A trauma surgeon (CA.), working separately and without knowledge of the CT findings, reviewed each patient’s chart to determine age, sex, mechanism of injury, need for an operation, days in the intensive care unit, total blood replacement, total days of hospitalization, and outcome. In addition, several indexes of traumathe injury severity score (155), the Glasgow coma score (GCS), and the revised trauma score (RTS)-were also calculated (Appendix). Change in spleen size was correlated with each of the other clinical and CT indexes of trauma mentioned in this section by use of the Pearson product moment correlation. A stepwise regression analysis

care

19 29 12(63) 5 6(32)

surgery

Clinical indexes

3 1*

liver

Lesion

Other

Enlargement (Group

2

(thick,

irregular defect) Shattered

Splenic I)

1

defect)

Shattered Laceration defect)

(Group

in parentheses

The lower the number

are percentages.

the more severe the injury.

years). None of the 44 patients was hypotensive in the emergency department, intensive care unit, or ward. All patients were admitted to the intensive care unit and remained there until care could be provided on the ward (mean stay, 4.5 days). Twenty-three patients (52%) required sungical procedures, most for orthopedic injuries. Only four laparotomies were performed to repair a urinary bladden (n = 1), pancreas (n 1), and spleen (n = 2). Transfusions were necessary for 21 patients (48%), 14 of whom had undergone surgical procedunes. The average clinical indexes of trauma were as follows: GCS 12.0, RTS = 10.7, and ISS 20.7 (Table 2). At examination with CT, 36 patients had evidence of liver or spleen injuries (liver, n = 20; spleen, n 11; both, n = 5), and 25 patients had evidence of intraperitoneal blood. Eight patients had none of these conditions and underwent repeat scanning for other reasons. The average splenic volume increased 25.6% between the first and second scan. Nineteen patients showed less than 10% increase in splenic volume and were considered to have no significant change (group 1). Twenty-five patients had an increase in splenic volume greater than 10% (group 2), with an average enlargement of 56% (Fig 1). Three spleens more than doubled in volume (Figs 2, 3). The average CT trauma score was 3.3 (liven, 1 .2; spleen, 0.8, blood, 1.3) (Table 2). Pearson product moment correlation revealed a small but statistically significant correlation between splenic enlargement and CT evidence of intnaabdominal hemorrhage

,psI

20

is 16

14 12 10 S

6 4 2 0 -I

Figure

1.

Distribution

of splenic

volume

change.

(.33, P < .05), number of units of blood transfused (.39, P < .01), the GCS (-.37, P < .05), and the RTS (-.33, P < .05). A stepwise regression analysis made with these four variables indicated that only 24% of the change in splenic size could be attnibuted to these four variables. All patients underwent at least one repeat CT examination, and 16 of the patients underwent a third examination. Between the second and third examinations, the spleen further enlarged by 20%. Change in splenic size peaked 6-7 days after injury.

DISCUSSION Splenic enlargement of greater than 10% occurred in 25 (57%) of hemodynamically stable patients after blunt abdominal trauma. We postulate that progressive splenic enlargement on CT scans is not a sign of deteriorating splenic status but a return of the spleen to normal size after a physiologic contraction. In healthy adult volunteers, Henderson et al

September

1990

b.

a.

Figure 2. Images from a 22-year-old woman injured in a motor vehicle accident. Her initial scan showed evidence of a splenic laceration, a liver laceration, and blood in the peritoneum. (a) A four-on-one composite view shows the spleen with a grade 2 laceration of the medial inferior margin. A minimal amount of blood is seen lateral to the spleen. The calculated volume of the entire spleen was 81 cm3. The patient was treated conservatively but needed 5 units of blood. (b) Follow-up CT scans through approximately the same levels and with the same magnification demonstrate partial resolution of the splenic laceration. The total splenic volume enlarged to 265 cm3, a 227% increase.

a. Figure tative spleen

b. 3. Images from a 25-year-old axial scan shows a small spleen. has

a slightly

lower

Hounsfield

ed conservatively, requiring tion), CT scan shows a large different than larity of splenic lar enlargement.)

spleen blood

a 2-unit increase

man injured in an automobile accident. (a) A represenThe total volume of the spleen was only 43 cm3. The value than the liver ( 9 HU). The patient was treatblood transfusion. (b) Five days later (same magnificain spleen size. Although the depth of respiration was

that of a, the spleen was imaged at approximately the same level. (Note vessels in hilum and similar splenic shape; other axial sections showed The total splenic volume was 155 cm3, a 250% increase from baseline.

in b has a slightly flow to the spleen

higher Hounsfield value than the liver, a result of either increased or differences between the timing of the injections in a and b.

(10) found that the average splenic volume was 219 cm3 ± 75 (standard deviation). In our adult patients, the initial splenic volume of 200 cm3 ± 106 was slightly below these standards, and the follow-up volume of 255 cm3 ± 111 was slightly above them. CT standards for splenic volumes in children were not found in the literature. The initial decrease in splenic size,

Volume

176

#{149} Number

simisimiThe

3

with eventual return to normal size, appears to be due to the systemic effect of trauma rather than to the local abdominal injury. Three of the four significantly but modestly correlated variables were measures of systemic rather than local trauma. The GCS classifies neunologic status, and yet it correlates significantly with changing splenic size. The RTS builds on the GCS, incorporating vital signs

such as blood pressure and respiratory rate. The ISS, the index most affected by direct trauma to the trunk, had the lowest correlation with change in splenic size. Total blood replacement is also potentially influenced by many injuries beyond the abdomen. The only direct measure of intnaabdominal injury that correlated significantly with changing spleen size was the CT estimate of intrapenitoneal blood volume. Splenic and hepatic lacerations, the most direct indicatons of abdominal visceral trauma, did not correlate significantly. Splenic contraction in response to exercise, hemorrhage, on administration of epinephrine is well documented in dogs. Muscle in the splenic capsule of dogs contracts, providing a source of autotransfusion in response to stress (11-13). In humans, there is no muscular capsule, but the visceral circulation is known to contract in response to adnenergic stimulation, decreasing blood flow to the spleen. Sandler et al (14) demonstrated this phenomena in patients undergoing left ventniculognaphy with administration of nadionuclides. They found that, with supine exercise, splenic radioactivity decreased 49% from that of the resting supine state. It gradually returned to baseline after cessation of exercise. Less

Radiology

#{149} 631

dramatic changes occurred when the patient stood erect. These changes are a systemic response to exercise, probably due to adrenergic effects on the splenic circulation. The liver does not show similar changes. It is likely that in our acutely injured patients, the spleen contracted under heavy adnenergic stimulation. With time and volume replacement, the spleen returned to normal size. This physiologic return is seen on the CT scan as progressive splenic enlargement. The circulating blood volume may have also influenced the size of the spleen. With aggressive fluid replacement and the resorption of extravascular fluid just prior to the physiologic diuresis, the spleen may enlarge in response to the increased circulatory volume. The spleen peaks in size 6 days after trauma, a fact that supports this explanation. In the vast majority of healthy patients studied with dynamic CT, splenic enhancement with contrast material exceeds liven enhancement, so that the spleen has a higher Hounsfield value than the liver (15,16). During our CT evaluation of splenic volume, 1 1 CT scans incidentally showed liver of greater Hounsfield values than the spleen. None of these spleens required surgery for splenic injuries, and most returned to normal attenuation on subsequent scans. We agree with Berland and Van Dyke (17) that diminished splenic enhancement with contrast material after blunt abdominal trauma is not necessarily a sign of splenic infarction on vascular injury. The altered spleen-to-liver density relationship may also be due to the adnenergic effect on splenic blood flow, medical diseases of the liven or spleen, variations in timing of scanning after intravenous injection of contrast material, or the other vagaries of measuring attenuation values. This study is limited by the somewhat heterogeneous nature of our patient population. Some of the patients were injured near the hospital and arrived in the emergency department after paramedic stabilization in the field. Others were flown by helicopter after stabilization at distant points. The interval between injury and scanning varied, and we often

632

#{149} Radiology

found it difficult to reconstruct the patient’s fluid intake and output. Many patients suffered from multiple injuries and often required transfusions or surgery for extraabdominal injuries. Other patients who were hypotensive at admission, on became hypotensive subsequently, would not have undergone serial CT scanning and would have been excluded from the study. Thus the patient selection process undoubtedly influenced the results. Multiple studies have demonstrated the ability of contrast material-enhanced CT to enable accurate diagnosis of visceral injuries after blunt abdominal trauma (1-7). We continue to believe that in hemodynamically stable patients with abdominal trauma, CT is an accurate diagnostic tool and that serial CT scans can be used to identify and monitor injuries. However, neither enlargement of the spleen on serial CT scans nor decreased splenic enhancement relative to the liver should be considered an indicator of a deteriorating condition.

3.

Resciniti A, Fink MP, Raptopoulos V. Davidoff 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.

4.

Federle RB Jr.

5.

Scatamacchia

CT. Radiology

6.

7.

severity regions

verity most

of trauma. severely

score

(ISS).-Each

is graded

1-6,

The

scores

injured

areas

on

for the are

motor

response.

This

provides

cal index of the condition with a head injury. (The as injury

severity

their statistical her help with

assistance and the manuscript.

Sylvia

Bartz

for

E.

R, Sones

Computed

tomo-

P. Kutner

M.

Accurate

of liver, kidney, and spleen mass by computerized axial Ann Intern Med 1979;

90:185-187.

10.

1 1.

13.

14.

15.

Acknowledgments: We thank Ronald Tikofsky, PhD, and Hannah Goodman, MS. for

Ford

measurement volume and tomography.

a numeri-

increases.)

RB,

B, Barlow

of the patient score decreases

Revised trauma score (RTS).-This score combines the GCS with assessment of blood pressure and respiratory rate (the score decreases as injury severity increases). #{149}

in adults:

impact of CT grading on management. Radiology 1989; 171:725-729. 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. Foley WD, Cates JD, Kellman GM, et al. Treatment of blunt hepatic injuries: role of CT. Radiology 1987; 164:635-638.

9.

squared

and added. Glasgow coma score (GCS).-This scale grades the effects of external stimuli on eye opening, pupil response, and best

V. Fink

trauma

graphic volumetric calculation reproducibility. Invest Radio! 1986; 21:272-274. Heymsfield SB, Fulenwider 1, Nondlinger

se-

three

Splenic

Staron

of six based

162:69-71.

Raptopoulos

8.

12.

injury

1987; SA,

MP, Silva WE.

APPENDIX body

MP, Griffiths B, Minagi H, Jeffrey Splenic trauma: evaluation with

16.

Henderson JM, Heymsfield SB, Horowitz J, Kutnen MH. Measurement of liver and spleen volume by computed tomography. Radiology 1981; 141:525-527. Guyton A. Textbook of medical physiology. Philadelphia: Saunders, 1986; 343. Vatner SF, Higgins CB, Millard RW, Franklin D. Role of the spleen in the periphera! vascular response to severe exercise in untethened dogs. Cardiovasc Res 1974; 8:276-282. Cuntheroth

WG,

Mullins

CL.

Uiver

and

spleen as venous reservoirs. Am J Physiol 1963; 204:35-41. SandIer P, Kronenbeng MW, Forman MB, Wolfe OH, Clanton JA, Partain CL. Dynamic fluctuations in blood and spleen radioactivity: splenic contraction and relation to clinical radionuclide volume calculations. J Am Coll Cardiol 1984; 3:12051211. Alpern MB, Uawson TL, Foley WD, et al. Focal hepatic masses and fatty infiltration detected by enhanced dynamic CT. Radiology 1986; 158:45-49. Nelson nardino

RC, ME.

the liver and and nonionic

Chezmar

JU, Peterson

Contrast-enhanced

spleen: agents.

comparison AJR 1989;

JE,

Ber-

CT

of

of ionic 153:973-

976.

17.

Benland LL, VanDyke JA. Decreased splenic enhancement of CT in traumatized hypotensive patients. Radiology 1985; 156:469-471.

References 1.

2.

Wing VW, Federle MP, Morris JA, Jeffrey RB, Bluth R. The clinical impact of CT for blunt abdominal trauma. AJR 1985; 145:1191-1194. Buntain WL, Gould HR, Maul! K!. Predictability of splenic salvage by computed tomography. J Trauma 1988; 28:24-34.

September

1990