Courtney

C. Neff,

MD

#{149} Eric

vanSonnenberg,

CT Follow-up Resolve after

of Empyemas: Percutaneous

In this prospective study, computed tomography (CT) was used to examinc the resolution of pleural abnormalities following radiologic catheten drainage of empyemas. Ten patients with empyemas surrounded by pleural peels underwent thoracic CT scanning at 4, 8, and 12 weeks aften removal of their catheter(s). The scans demonstrated extensive pleural thickening 4 weeks after catheter removal in all 10 patients. The pleural thickening had decreased 8 weeks after catheter removal. At 12 weeks, the pleura was essentially normal in four patients, demonstrated only a small area of plaquelike thickening in four patients, and was mildly thickened in two patients. This study demonstrates that the pleural surfaces have a remarkable capacity for healing after empyema drainage. The pleural peel resolves in most cases. These results suggest that decontication need not be performed routinely when such empyemas are encountered; rather, patients should be treated on an individualized basis and studied with serial CT to determine the necessity of decortication. Index terms: Empyema, 66.76 66.1211 #{149} Pleura, CT, 66.1211

Lung,

#{149}

Pleura,

#{149}

CT,

diseases,

66.76

Radiology

1990;

176:195-197

From the Department of Radiology and Thoracic Surgery Service (D.W.L., Salem Hospital, Salem, MA 01970 and I

partment

California,

of Radiology

San

(E.V.),

University

MD

(C.C.N.) ASP.),

the

Deof

Diego Medical Center, San Diego. From the 1989 RSNA annual meeting. Received December 15, 1989; revision requested January 26, 1990; revision received February 12; accepted March 7. Address reprint requests to C.C.N. RSNA, 1990

T

Dexter

#{149}

W. Lawson,

Anthony

S. Patton,

#{149}

Pleural Catheter

robe of percutaneous catheter drainage of empyemas has expanded rapidly. In 1982, vanSonnenberg et al reported the successful use of this technique after standard chest tube drainage had failed (1). Since then, catheter drainage has been reported as a primary method of empyema management with cure rates of 80%-90% (2-4). Despite the reported success of this technique, catheter drainage of empyemas has not gained wide acceptance by thonacic surgeons (5,6). In Surgical Diseases of the Pleura and Chest Wall, Hood claims that even the placement of a barge intencostab tube should be attempted only if the pleural process is of less than 3 days duration; if the empyema has been present for more than 3 days, rib resection with tube drainage is advocated (5). Hood states: “Multi-loculation, fibninous debris, pleural ‘peel,’ and poor tube placement are the usual reasons for failure (of intercostal tubes)” (5). The problems posed by multiloculation, fibrinous debris, and poor tube placement are well known to the interventionab radiologist (1-4), but the significance of the pleural peel and its eventual fate after successful drainage of the infected fluid is poorly understood. A pleural peel forms as a result of fibrim deposition on the pleural sunfaces of an ernpyema. This peel can be observed directly only at thonacotorny; the timing of its evolution into the dense scar of chronic ernpyema is poorly understood. This fibrinous layer is the key to the ernpyerna staging system used by the American Thoracic Society (7). Stage I empyemas are exudative, characterized by thin pleural fluid with a low white blood cell count. Stage II empyernas are fibropurulent, characterized by thicker, more turbid fluid with the appearance of fibnin on the pleural surfaces that begins to form a peel around the lung. Stage III empyemas are chronic, characterized by the HE

MD

MD

Peels Drainage’ pleural

peel

trapping movement.

becoming

the

lung,

Surgeons

organized,

en-

restricting

its

and

have

emphasized

the

need for decortication due to the propensity of this peel to cause lung entnaprnent with resultant impairment of pulmonary function. Our experience did not appear to support this contention. None of our prior patients

had

developed

ment after age despite nent

pleural

catheter undertaken question:

lung

peels

at the

nab peel

after

effective

pleural

catheter

drain-

CT to as-

AND

January

1988,

we

utive

patients

that

1986

METHODS through

prospectively

age of stage

occurred

period following of empyernas.

PATIENTS

the

of

Sequential the means

changes

over a 3-month catheter drainage

From

time

placement. This study was to answer the following What happens to the pleu-

age of an empyema? scanning provided sess

entrap-

successful catheter drainthe presence of promi-

December

studied

10 consec-

referred

for catheter

II empyemas

who

criteria:

(a) Aspirated

following

drain-

met all of fluid

was thick and turbid and culture results were positive for bacteria! organisms including Streptococcus pneumoniae (n 4), Staphylococcus aureus (n = 2), Bacteroides sp (n 1), Enterococcus sp (n 1), Streptococcus viridans (n 1), and a mixed gramnegative bacilli (n 1). (b) There was radiographic

evidence

that

the

pleura!

fluid had been present for at least 7 days. (c) CT demonstrated thick pleural surfaces surrounding the fluid. (d) CT scans obtained after drainage showed that all of the pleural fluid was removed. Empyemas

that

few days study,

(stage

since

Chronic

were

present

I) were

they

contain

empyemas

age of these

no

present

months (stage III) were there is no proved role

densely

for

excluded pleura!

scans

due

to fibrin

peel.

excluded since for catheter drain-

fibrotic

that the pleural was

a

the

for many

lesions.

her it had been established in several tients who underwent decortication

drainage

only

from

peel seen

Earpaafter

on CT

deposition.

195

a.

b.

c. Figure

with

1.

CT

slowly indicate

of a 38-year-old

discovered

of

after

(c) Scan

collapsed

of catheter 4 weeks

after

(a) Arrows peel. (b) Note

empyema

insertion obtained

man

4 weeks

responding pneumonia. thick walls of pleural

thickness

days

scans

empyema

8

walls

(arrow).

after

catheter

re-

moval reveals pleural pseudotumor. (d) Scan obtained 8 weeks after catheter removal shows a decrease in the size of the pseudotumon.

(e) Scan

ter removal

obtained 12 weeks after shows plaquelike pleura!

cathescar

(arrow).

e.

d.

a. Figure astina! pleural

2.

CT

scans

of a 68-year-oh

abscess (A) (a) seen with adjacent thickening. CT scan at 12 weeks

Catheter drainage was attempted on every referred patient with a stage II empyema. Two patients with stage II empyemas were excluded from the study when the empyemas proved to be multi!oculated; the fluid could not be removed even with several catheters. Surgical drainage with

manual

tive.

196

Radiology

#{149}

lysis

of adhesions

was

(E) (b). Scan mild residual

empyema

(d) shows

cura-

The

study

obtained

group

en and four men to 84 years (mean,

emas

were

chest

radiographs

was

then

4 weeks

pleural

initially

consisted

of six

ranging in age 64 years). The

detected in a!!

aspirated

after

with

needles under ultrasound in seven patients, CT

ance

and

two,

were

removed

one.

According

fluoroscopic

tients

19

(c)

demonstrates

guidance

Fluid

tients,

20-

All undergo

guidin

to the

underwent to obtain

sention used for

on standard

10 patients.

for analysis

worn-

from empy-

or 22-gauge (US) guidance in

catheters

moderate

thickening.

catheter

and

placement

CT was

patients three

material-enhanced ed to the areas

protocol,

all

ten

pa-

CT prior to catheter inbaseline images. US was used

in

eight

gave informed consent follow-up, non-contrast

that

pa-

in two. to

CT procedures limitpreviously contained

July

1990

empyemas. CT was performed 4, 8, and 12 weeks after removal of the empyema catheter(s) with acquisition of contiguous 10-mm sections on a GE 9800 scanner (GE Medical Systems, Milwaukee). One patient was unable to return for scanning at 8 weeks,

and

another

patient

refused

to

undergo scanning at 12 weeks. Eight patients had empyemas secondary to bacteria! pneumonia. Two patients had empyemas and mediastinal abscesses secondary to late complications of Boer-

haave

syndrome.

Eight

empyemas

were

located posteriorly or postenolaterally; six of these were in basilar regions of the involved hemithora.x, and two were in the middle of the thorax. The other two empyemas were subpulmonic. Al! 10 patients were being treated with intravenously administered antibiotics at the time

of catheter

insertion.

The volume of fluid removed from empyemas varied from 75 to 850 mL. nine empyemas 12- and 14-F catheters

were

used.

An 8.4-F catheter

the In

was used

in

the 75-mL collection. One catheter was sufficient in eight patients, but in two patients two catheters were required for complete fluid removal (as determined with CT). Catheters were left in place Until

all

drainage

ceased.

ter drainage with a mean ic antibiotics after catheter

Duration

of cathe-

ranged from 4 to 18 days, of 10 days. Organism-specifwere continued for 8 weeks removal.

RESULTS Seven

patients

had

complete

meso-

bution of fever and leukocytosis in 72 hours of empyema drainage.

with-

The other three patients had extensive associated pneumonia, and defervescence occurred over 7-1 1 days. There was no incidence of empyema recurrence all patients

scanning moval.

in the study group, were asymptomatic

12 weeks They remain

after catheter asymptomatic

clinical follow-up 36 months.

ranging

from

Figures 1 and 2 show the tion of pleural abnormalities patients

over

and at CT

a 12-week

meat 12 to

nesoluin two

period.

In

one patient thick-walled empyema developed after inadequate treatment of pneumonia (Fig la,lb). In another patient a mediastinal abscess and empyema resulted from delayed diagnosis of Boerhaave 2b).

The

CT scans

ten catheter

five

patients

Volume

176

(Fig

had

(pseudotumoms) lc).

The

extensive

Number

#{149}

4 weeks

demonstrated

masses

patients

(Fig

obtained

removal

pleural-based in five

syndrome

1

other

pleural

2a,

af-

thickening at 4 weeks (Fig 2c). The scans obtained after 8 weeks showed partial resolution of the pleural pseu-

with

dotumors and the pleural thickening in all patients (Fig id). Twelve weeks after catheter removal, a small area of plaquelike thickening was demonstmated in the pleura in four patients (Fig le). There was little or no pleunal thickening in four patients, while the pleura showed moderate focal pleural thickening in the other two patients (Fig 2d).

DISCUSSION The “split pleural sign,” a useful CT sign to diagnose empyema, is dependent on contrast enhancement of the pleural peel. This indicates that early in its course the pleural peel has a significant vascular supply (8). This blood flow should permit antibiotic penetration into the pleural peel until the microvasculatune becomes obliterated by fibrosis. The length of the time that it takes for a pleural peel to become dense scar tissue, which is impervious to antibiotics, must be variable. In 1971, Crofton and Douglas suggested that this process takes about 12 weeks (9), while more recently Wilcox wrote: “The chronic stage (of empyema) begins about the 6th week after the onset of the acute illness” (10). Our data show that during the first

few

weeks

peels

are

ence

does

after not

not

formation,

static,

and

necessarily

pres-

localized.

be assumed from massive empyemas

It cannot, our

that most

repair

of the

vanSonnenberg E, Nakamoto 5K, Mueller PR, et al. CT- and ultrasound-guided catheter

drainage

chest-tube

of empyemas

failure.

after

Radiology

1984;

151:349-353.

Westcott J. Percutaneous age of pleural effusion

2.

1985; 3.

O’Moore PV, al. Sonographic and

4.

Mueller PR, guidance

therapeutic

ral

catheter

and

drain-

empyema.

AJR

144:1189-1193.

space.

Simeone JF, of diagnostic

interventions

AJR

Merriam

MA,

Lambiae

RE,

1987;

percutaneous fluid

the

JJ, Dorfman

Cronan

pleural

in

et pleu-

149:1-5.

Haas

guided

RA.

GS,

Radiographically catheter

collections.

drainage

AJR

of

1988;

151:1113-1116.

5.

Hood

RM.

and

chest

1986;

Surgical wall.

diseases

of the

Philadelphia:

pleura

Saunders,

95.

6.

Orringer basics.

7.

American

MB. Thoracic empyema: Chest 1988; 93:901-902. Thoracic

Surgery.

culous

Society

to

Subcommittee

Management

empyema.

back

of non-tuber-

Am

Rev

Resp

Dis

1962;

85:935.

8.

Stark

DD,

drasky lung

AE, abscess

and

Federle

MP,

Webb and

computed

141:163-167. Crofton

9.

Goodman

PC,

10.

Wilcox rax.

tomography.

J, Douglas

BR. In:

The

Glenn

diovascular

11

on

.

Conn: 155.

A.

AJR

J

empyema. 12.

90:849-885 Hood RM. and 1986;

and

chest

pneumotho-

ed.

Thoracic

4th

ed.

and

car-

Norwalk, 1983;

MJ, Orringer MB. of adult thoracic

Thorac

Cardiovasc

Surgical

diseases

wall.

thoracis.

ed. Oxford, 1971; 172.

Appleton-Century-Crofts, JH, Botham management

1983;

Empyema

pleura

WWL, surgery.

Lemmer Modern

Po-

WR. Differentiating empyema: radiography

In: Respiratory diseases, 15th England: Blackwell Scientific,

therefore,

all of the pleural space and encasing the lung will respond well to percutaneous drainage nor that extensive pleural peels associated with such empyemas will necessarily resolve they did in our patients. The standand method of practice syndrome is operative

1.

preclude

findings involving

and

References

on

successful catheter drainage. Clearly, the peels in these 10 patients with stage II empyemas were not metabolicably inactive scars. Rather, they passed through stages of healing that included the formation of pleural pseudotumoms in 40% of the cases. With complimentary antibiotic therapy, the pleura returned to a nearly normal appearance. The pleural infections in our series

were

drainage

emas can usually be cured with catheter drainage. Follow-up CT scans will demonstrate inadequate drainage or failure of the lung to reexpand at which time surgery can still be performed without significant delay. U

pleural their

both

esophagus. It should be noted that the cases reported here were unusual in that they responded to conservative management with drainage alone. Some thoracic surgeons still advocate early decortication for all stage II empyemas (11,12). The results reported by Merriam et al (4) and our CT findings suggest that localized empy-

Philadelphia:

Surg of the

1985; pleura

Saunders,

83.

as

in Boerhaave treatment

Radiology

#{149} 197