MarIa

Hernanz-Schulman,

James Walter

B. Atkinson, H. Merrill,

MD MD MD

#{149} Sharon

M. Stein, G. Kirchner, MD C. Fleischer, MD

#{149} Sandra #{149} Arthur

MB, ChB #{149} Richard

#{149} Wallace

W. Neblett, MD

M. Heller,

MD

Pulmonary Sequestration: Diagnosis with Color Doppler Sonography and a New Theory ofAssociated Hydrothorax’ The

diagnosis

of pulmonary sequestraditionally relied on angiographic demonstration of a systemic artery to the sequestered lung tissue. Rarely, extralobar sequestration can be associated with tension hydrothorax, which in the past has invariably led to fetal hydrops and death. The authors report the cases of three infants who had initially undergone color and spectral Doppler analysis; in two of them, extralobar sequestrations were associated with congenital hydrothorax. All three patients underwent surgical resection and histopathologic evaluation of their sequestrations. On the basis of the findings, the authors believe that torsion of the sequestration occludes the efferent venous and lymphatic channels, initiating the accumulation of pleural fluid and subsequent hydrops through systemic venous obstruction. Color Doppler made possible the identification of minute tration

has

feeding

vessels,

diagnostic

obviating

further

sequestration is part of of bronchopulmonary foregut anomalies in which a portion of lung parenchyma does not communicate with the tracheobronchial tree and usually receives its arterial supply from a systemic vessel. Historically, the diagnosis has rested on arteriography, although the value of noninvasive techniques in the evaluation of pulmonary sequestration

clear,

has

within the airless Doppler analysis

ULMONARY

a spectrum

been

emphasized

in the

recent

literature (1-9). the use of color to facilitate the

To our knowledge, Doppler sonography diagnosis has not been

reported

radiobogic

in the

literature.

We discuss three cases of sequestration diagnosed with sonography, including two cases in which identification of the characteristic aberrant arterial supply was made possible by color Doppler sonography and in which the spectral waveform and surgical and histologic findings provided an etiologic clue to an unusual complication of the lesion.

normalities,

563.1556

Ultrasound

#{149}

(US),

Dop-

1991; 180:817-821

CASE Patient weeks 2, para

1.-A

gestation 1 mother.

the

drainage

to a 26-year-old,

at 31 gravida

Ra-

R.M.H., A.C.F.), Pediatric Surgery (W.W.N.), Pathology (J.B.A.), and Cardiothoracic Surgery (W.H.M.), Vanderbilt University Medical Center, Nashville, TN 37232-2675. Received March 11, April 10; revision reMay 3. Address reprint

over

the

next

chest ralesion at

the condition sonography

After

stabilized,

state-of-the-art

of the patient was performed with

equipment

and

pler capability

(Fig ib) enabled

tion of a vessel aorta, coursed

that arose superiorly,

showed

high

color

Dop-

identifica-

in the abdominal and ramified

lung. The spectral-wave of this vessel (Fig ic)

systolic

peaks

with

reversed

diastolic flow indicative of a high-resistance capillary bed. Venous signals were not identified. The preoperative diagnosis was

extralobar

pulmonary sequestration. the baby had a normal bib-

At surgery,

bate, aerated left lung. Inferiorly, the sequestered lung was bluish and was connected to the feeding vessels along the lower left mediastinum via a narrow pedide, which had allowed the sequestered lung

to twist.

moved patient

The

sequestration

was

without complications, was discharged from later.

Pathologic

re-

and the the hospital

that the tissue was composed lung and dilated lymphatic

with

focal

id). Patient

2.-A

areas

4

examination

of yes-

of hemorrhage

2.4-kg

boy

was

(Fig

born

at 36

reaccumulation At birth,

tension hydrothorax, which was successfully via internal catheter

la). of Radiology and S.M.S., S.G.K.,

continued

revealed polyhydramnios and a left-sided tension hydrothorax; thoracentesis was performed in utero, with rapid subsequent

Prenatal

of the

sonography

had

fluid.

the neonate presented distress that necessitated

with en-

dotracheal intubation. A chest radiograph showed an opaque left hemithorax with contralateral mediastinab shift. The initial sonogram, obtained at bedside, clarified the contents of the left hemithorax (Fig

the Departments Sciences (M.H.S.,

im-

sta-

the left base.

sels

girl was born

2.5-kg

with

respiratory

several days. Postthoracostomy diographs suggested a masslike

immature

REPORTS

transudate,

in the baby’s

to a 20-year-old, gravida 4, para 3 mother. A prenatal sonogram obtamed at 27 weeks of gestation had revealed polyhydramnios and a left-sided

respiratory

1991; revision requested ceived May 1; accepted requests to M.H.S. 0 RSNA, 1991

tus;

showed

pIer studies

1 From diological

straw-colored

provement

days

studies.

Index terms: Hydrothorax, 60.76 #{149}Infants, newborn, respiratory system, 60.145, 60.76 Lung, abnormalities, 563.1556, 60.145 #{149} Pulmonary veins, abnormalities, 945.15 #{149}Thorax, ab-

Radiology

P

Within

the fluid-filled

left thoracic

cavity, an airless mass was present inferiorly; branching echogenic linear structures

seen

in structurally

ebectatic

pulmonary

absent. resent

The structure lung because

normal parenchyma

was

believed

weeks

gestation

treated drainage

into the amniotic space. Analysis of the pleural fluid was consistent with a transudate of plasma. The neonate was born with the intact catheter in place (Apgar score of 8/9 at I and 5 minutes). Chest radiographs revealed a masslike lesion at the left base. Postnatal sonography documented (Fig 2a-2c)

homogeneously

airless

lung

at the

at-

left base conforming to the costophrenic sulci. A feeding vessel could not be visu-

to rep-

ally identified despite use of high-resolution, state-of-the-art equipment. However,

but were

shape conformed sulci. The resolution its

to the costophrenic of the bedside equipment did not allow further characterization of the abnormality. Tube thoracostomy drained 60 mL of

with

color

systemic

Doppler, vessel

immediately

the left lateral

was below

aspect

the tortuous demonstrated. the

diaphragm

of the aorta

feeding It arose from

and 817

C.

d. 1. Patient

Figure

seemingly

1.

(a) Bedside

left coronal

small left lung with reverberating

(b) Left coronal

color

Doppler

sonogram

echoes

sonogram

reveals

shows

a very

large,

from air is floating

the feeding

artery

fluid-filled

superiorly.

through

hemithorax The

unaerated

unaerated

with

concave

sequestration

sequestration

(S) arising

medial

and lateral

(arrows)

is present

from

borders.

A

inferiorly.

the left lateral

aspect

of

the aorta, just below the diaphragm. Solid arrows = thoracic aorta, open arrow = abdominal aorta. (Figure is turned 90#{176} clockwise.) (c) Spectral Doppler tracing of the feeding artery shows systolic peaks with high-frequency shift and diastolic flow reversal. Two systoles were missed due to patient motion. (d) Pleural surface of lung. Subpleural lymphatic channels (arrowheads) are markedly dilated, and focal interstitial hemorrhage extends to the pleural surface (arrows). (Hematoxylin-eosin stain; original magnification, x95.)

coursed posteriorly and superiorly into the sequestered lung. Diastolic flow was low but was present at spectral-wave Doppler analysis, and venous signals were detectable. At surgery,

appeared

the

normal

compressed

racic

mass,

which

50%

of the

hemithorax.

of a narrow

hyperemic

818

and

no discoloration

#{149} Radiology

tho-

approximately The

vascular

sequestration pedicle.

lion was markedly but

left lung

occupied

ply to the extralobar sisted

bibobate

by the lower

The

edematous was

actively

was

sup-

consequestra-

and leaking

present.

fluid,

The

pa-

tient

had an uneventful

course

and

pital several Pathologic specimen

dilated hemorrhage

was

postoperative

discharged

from

days after surgery. examination showed consisted

lymphatic (Fig

of lung

channels 2d).

The

tissue

that the with

but no areas feeding

noted to be mildly tachypneic, and a prominent murmur was heard; he was referred to our institution for evaluation.

the hos-

vessel

was less than 1 mm in luminal diameter and had actually been overbooked when the gross specimen was sectioned. Patient 3.-A 3.0-kg boy was born at

term to a 19-year-obd gravida 2, para 2 mother. During a routine visit to his pediatrician at age 8 weeks, the infant was

of

A chest

radiograph

(Fig

3a)

revealed

a

triangular mass at the right base, with rounded areas of decreased opacity but no air bronchograms. Sonography (Fig 3b-3d) showed largely de-aerated parenchyma

with

scattered

echoes

consistent

with

bronchial aeration. A very large artery arose from the celiac axis and crossed crus

of the

formation. in caliber

diaphragm

to supply

The artery was to the descending

the

roughly aorta

September

nonthe mal-

equal at the

1991

Figure 2. Patient

2. (a) Left coronal color sonogram shows the origin of the artery (straight arrow) from the abaorta just below the diaphragm arrows). This vessel was less than 1 mm in diameter (compare a with C). P = spleen, S = sequestration. (b) Image sequential to a traces the tortuous artery into the lung. Note the spine (black S), indicating a more posterior angulation compared with that in a. Curved arrows point to diaphragm. P = spleen, white S = sequestration. (c) ImDoppler feeding dominal (curved

age analogous visualize color

to a demonstrates

feeding

Doppler

artery mapping.

inability

in the absence The

gate

to

of

is in the

vessel, which was identified with color on a separate screen. Note presence of forward diastolic between

flow but relatively large difference systolic and diastolic flow velocities.

(d) Dilated lymphatic channels matoxylin-eosin stain; original xi2O.)

a.

in lung. (Hemagnification,

b.

C.

same level, throughout

of pulmonary

and prominent flow occurred diastole. Although the artery

was readily visible, Doppler cilitated tracing of the venous

guidance drainage

radiology

fato

the left atrium. was intralobar

The preoperative diagnosis sequestration. At surgery, an intrabobar sequestration was well anchored and was contained entirely within the basal portion of the right lower lobe. An anomalous esophageal bronchus

entered

the

sequestration,

and

there were multiple inflamed hilar nodes. A right lower lobectomy was performed without complications. The pathologic findings were consistent with pulmonary sequestration with acute bronchitis (Fig 3e). The lymphatic channels were not dilated.

DISCUSSION To our knowledge, this is the first description of color Doppler as an adjunct to the sonographic diagnosis

Volume

180

#{149} Number

3

sequestration literature.

in the

As far as we

know, spectral Doppler analysis in extrabobar pulmonary sequestration associated with hydrothorax has never been previously described. We have found only 10 previous reports of extralobar pulmonary sequestration associated with tension hydrothorax (10-16). To our knowledge, patients 1 and 2 are the first two surviving infants with this condition. The pathogenesis of the tension hydrothorax and subsequent hydrops has

remained

elusive.

Some

authors

have failed to speculate on its origin (10,12,13,15). Others have suggested a vascular etiology of overcircubation as the initiating event (i4). Another group of investigators, remarking on dilated lymphatic channels on histologic sections, have implicated abnor-

mal

lymphatic

physiology

Patient sequestered was

roughly

drainage in the pathohydrothorax (ii). 3 had very large flow to his lung: The feeding vessel of the

equal

in size

to the

de-

scending aorta, which diminished in size by approximately 50% after its takeoff. However, no pleural fluid surrounded this intralobar sequestration, and the lymphatic channels were not dilated on histologic sections. These facts belie the theory of excessive flow as the cause of the pleural effusion associated with Sequestration. The narrow pedicle in patients 1 and 2 allowed for torsion of the sequestration, thus producing obstruction of the efferent lymphatic channels and veins. As more and more fluid accumulates in the pleural space, perhaps a vicious cycle is initiated,

Radiology

#{149} 819

b. Figure

3. Patient

3.

(a) Anteroposterior

C.

ra-

diograph shows the abnormal area of pulmonary parenchyma at the right base. Rounded air spaces and absence of air bronchograms raised initial suspicion of sequestration. An upper right rib anomaly was also present.

(b) Anterior

sagittal

color

Doppler

sonogram

shows the large feeding vessel (straight arrows) to the sequestration (5). A = aorta, L liver. Curved arrow points to the diaphragm. (C) Transverse sonogram through the sequestration with color guidance (not shown) en-

abled

identification

gate) pling.

with venous (d) When

of a cystic

space

(Doppler

at Doppler signal was lowed and the transducer was angled cordingly, the venous drainage could traced to the left atrium (La); straight points to the interatrial septum. Curved

row indicates ferior (Ra).

vena

signals the venous

the eustachian cava

drains

valve

into

(e) Photomicrograph

the

samfolacbe arrow ar-

as the in-

right

of lung.

=

d.

atrium

Most

the lung parenchyma has been replaced by inflammation and organizing pneumonitis secondary to recurrent and ongoing infeclion. Only occasional, mildly distended lymphatic channels (arrows) are evident. (Hematoxylin-eosin stain; original magnification, x95.)

with

increasing

resulting in more sive torsion. This

intrathoracic frequent theory

volume and would

extenalso

explain the dilated lymphatic channels observed within the sequestration of our first two patients and in those cases in the literature in which the pathologic findings are described

about its pedicle; histologic examination revealed multiple areas of hemorrhage. The waveform of patient 2, on the other hand, showed some diasflow.

At surgery,

this

infant’s

se-

questration was edematous, but no discoloration was present; areas of hemorrhage were absent from the histologic sections. We postulate that long-term, ongoing decompression of the hemithorax in patient 2 provided a smaller space in which the lung 820

#{149} Radiology

could not twist as easily, thus interrupting the vicious cycle. As more patients with this anomaly come to medical attention, our theory can be further evaluated. Specifically, it would be interesting to note prospectively the anatomic relationship and vascular flow pattern of extralo-

However,

bar

setting, rested

sequestration

not

associated

with

hydrothorax. The previous reports of extralobar sequestration and hydrothorax do not elaborate on the thoracic attachments of the sequestered lung. However, in a review article

(11,13,14). Analysis of the spectral waveform supports a hypothesis of venous obstruction. Diastolic flow was reversed in patient 1. At surgery, this infant’s sequestration had bluish discoloration and appeared to be actively twisting

tolic

e.

of

of 547

cases

133

well-documented

bar

sequestration

cases

of extralo-

associated

are reported.

state

hibited

(17),

not

hydrothorax thors

of sequestration

that

the

a variety

the surrounding connections astinum,

The

au-

sequestrations

tissue, lower

with

diaphragm.

medi-

Further-

more, tension hydrothorax is not a feature of intralobar sequestrations, which are well anchored within a pulmonary lobe. Although we have not actively disproved a primary bymphatic malformation as the initiating causative

and

factor,

surgical

the

and

spectral

pathologic

the

presence

an impeded

a systemic

a chronically

the diagnosis on angiographic

of systemic

ex-

vessel

inflamed,

nonsequestered segment However, in the appropriate

tion

efferent than event.

of lung. clinical

traditionally documenta-

arterial

has

supply

sequestered segment. More many experienced surgeons

to the recently, have

come to rely on computed tomography (CT), magnetic resonance (MR)

imaging,

and

invasive

diagnostic

sonography

in the

evaluation

congenital

anomaly.

CT is optimally suited tion of aerated pulmonary but

nonof this

for evaluaparen-

its obligatory

axial

scan-

ning plane severely limits its ability to delineate the systemic vascular supply.

MR

ideal

imaging

modality

is, in many

with

which

ways,

the

to assess

tracings

these anomalies, because the systemic supply may arise from the thoracic aorta, at a level inaccessible to the sonographic beam. However, the high cost of MR imaging and the necessity

findings

of sedation

suggest

that

should

become

the

in our patients and our review of the literature support a vascular theory to

explain

that

persons,

supply

chyma,

including

lobe,

In older may

interesting ex-

of connections

to the

and

with

it seems

circulation with obstructed lymphatics and veins, rather cessive flow, is the initiating

of hydrothorax.

not

procedure The

MR imaging first

diagnostic

of choice. basilar

location

of many

September

of

1991

these

lesions

and

the

absence

of aera-

tion provides an excellent acoustic window for sonography, especially neonates and infants. As illustrated our

cases,

state-of-the-art

in by

equipment

and

color Doppler capability can guide and facilitate this search. The feeding vessel in patient 3 was very large and found easily; however, the vessel

in patient

2 was

1 mm in diameter, have been identified guidance.

Color

4.

and

approximately

it would not without Doppler

Doppler

5.

6.

7.

sonography

will prove particularly useful proving the overall accuracy examination and in obviating preoperative studies. U

in imof the further

8.

9.

References 1. 2.

3.

Felker RE, Tonkin IL. Imaging of pulmonary sequestration. AJR 1990; 154:241-249. Wimbush KJ, Agha FP, Brady TM. Bilateral pulmonary sequestration: computed tomographic appearance. AJR 1983; 140: 689-690. Naidich DP, Rumancik WM, LeFleur RS, Estioko MR, Brown SM. Case report: in-

10.

11.

tralobar pulmonary sequestration-MR evaluation. J Comput Assist Tomogr 1987; 11:531-533. Naidich DP, Rumancik WM, Ettenger NA, et al. Congenital anomalies of the lungs in adults: MR diagnosis. AJR 1988; 151:1319. Oliphant L, McFadden RG, Carr TJ, et al. Magnetic resonance imaging to diagnose intralobar pulmonary sequestration. Chest 1987; 91:500-502. Thind CR, Piling OW. Case report. Pulmonary sequestration: the value of ultrasound. Clin Radiol 1985; 36:437-439. West MS. DonaldsonjS, Skolnik A. Pulmonary sequestration: diagnosis by ultrasound. J Ultrasound Med 1989; 8:125-129. Kaude JV, Laurin S. Ultrasonographic demonstration of systemic artery feeding extrapulmonary sequestration. Pediatr Radiol 1984; 14:226-227. Newman B. Real-time ultrasound and color-Doppler imaging in pulmonary Sequestration. Pediatrics 1990; 86:620-623. Romero R, Chrvenak FA, Kotzen J, Berkowitz RL, Hobbins JC. Antenatal sonographic findings of extralobar pulmonary sequestration. J Ultrasound Med 1982; 1:131-132. Lucaya J, Garcia-Conesa JA, Bernado L. Pulmonary sequestration associated with unilateral pulmonary hypoplasia and massive pleural effusion. Pediatr Radiol 1984;

12.

13.

14.

15.

16.

17.

Kristoffersen SE, Ipsen I. Case report: ultrasonic real time diagnosis of hydrothorax before delivery in an infant with extralobar lung sequestration. Acta Obstet Gynecol Scand 1984; 63:721-723. Weiner C, Varner M, Pringle K, Hem H, Williamson R, Smith W. Case reports: antenatal diagnosis and palliative treatment of nonimmune hydrops fetalis secondary to pulmonary extralobar sequestration. Obstet Gynecol 1986; 68:275-280. Thomas CS, Leopold GR, Hilton 5, Key T, Coen R, Lynch F. Fetal hydrops associated with extralobar pulmonary sequestration. J Ultrasound Med 1986; 5:668-671. Reece EA, Lockwood CJ, Rizzo N, Pilu G, Bovicelli L, Hobbins JC. Intrinsic intrathoracic malformations of the fetus: sonographic detection and clinical presentation. Obstet Gynecol 1987; 70:627-632. Hruban RH, Shumway SJ, Orel SB, Dumler JS, Baker RR, Hutchins GM. Congenital bronchopulmonary foregut malformations: intralobar and extralobar pulmonary sequestrations communicating with the foregut. AmJ Clin Pathol 1989; 91:403-409. Savic B, Birtel FJ, Tholen W, Funke HD, Knoche R. Lung sequestration: report of seven cases and review of 540 published cases. Thorax 1979; 34:96-101.

14:228-229.

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Radiology

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