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325

Abnormalities of the Gallbladder After Extracorporeal Shock-Wave Lithotripsy: Imaging Findings

William E. Torre& Bruce R. Baumgartner William J. Casarella

To qualify for treatment with biliary extracorporeal shock-wave lithotripsy (ESWL), patients must have sonograms that show gallstones and oral cholecystograms (OCGs) that show normal opacification (indicating normal function) of the gallbladder. We have noted that sonograms and OCGs made 6 weeks to 6 months after ESWL sometimes show abnormalities that were not visible on these images before ESWL. In these cases, the gallbladder appears contracted on sonograms and is poorly visualized on OCGs. To

determine how often this occurs and to study its significance,

we analyzed the posttreat-

ment sonograms and OCGs in 174 patients who underwent ESWL After ESWL, sonograms showed a contracted gallbladder and OCGs showed poor function in 25 (14%) of the 174 patients. One patient (4%) was lost to follow-up. In 17 (68%) of the 25 patients, the abnormalities were transient (findings on sonograms and OCGs returned to normal by 12 months after ESWL). In the other seven patients (28%), the abnormalities persisted (all seven subsequently had a cholecystectomy); this is a cholecystectomy rate twice that in the patients with normal findings on sonograms and OCGs after ESWL (20/149 or 13%). All 25 patients with abnormalities after ESWL had gallstone fragments at 6

weeks, as did 146 of the 149 patients with normal-appearing gallbladders When these abnormalities persist (in approximately one third of patients), tomy is often required. cholecystitis, a process likely. AJR

159:325-327,

The cause of the abnormalities is unknown, although that is not detectable by pre-ESWL imaging techniques,

August

Extracorporeal patients

with

variety

of lithotripters,

chronic seems

1992

shock-wave

20,000

after ESWL cholecystec-

lithotripsy

symptomatic

(ESWL)

has been used to treat more than worldwide. Investigators, using a

cholelithiasis

have shown

the safety

and efficacy

of ESWL

in selected

patients with cholelithiasis [1-8]. All biliary lithotripsy clinical trials done in the United States require that potential patients meet approved criteria such as having a specified number and size of gallstones. All patients must have a functioning

gallbladder

shown

on oral cholecystograms

(OCG5),

and the gallstone(s)

visible on sonograms. All clinical trials require postlithotripsy up to 6 months; imaging studies done at the follow-up sonography, OCG, or both.

As we began to image our patients Received January 21 , 1992; accepted vision February 25, 1992. All authors: Department of Radiology,

after

re-

University School of Medicine, 1364 Clifton Rd., N.E., Atlanta, GA 30322. Address reprint requests to W. E. Torres. 0361 -803X/92/1 592-0325 © American Roentgen Ray Society

their initial follow-up

6 weeks

biliary ESWL, we saw several patients who had contracted gallbladders sonography. It was decided to evaluate gallbladder function specifically

patients, Emory

during

and thus we added a 6-week

This was done

in addition

OCG examination

to the required

described in the subjects and methods evaluate the prevalence of contracted faint/nonvisualized

causes

gallbladders

and significance.

on OCGs

follow-up

imaging

must be

follow-up at intervals examinations include

to the follow-up procedures,

after

shown by in these

regimen. which

are

section. The purpose of this study is to gallbladders shown on sonograms or of after

ESWL

and to consider

the possible

326

TORRES

Subjects

and Methods

In 1988, our center began a clinical trial to evaluate ness and safety of ESWL using the MPL-9000 (Dornier

the effectiveMedizintech-

nik

double-blind

GmbH,

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manner,

Germering,

ursodeoxycholic and

In

the need

a prospective

for adjuvant

chemolysis

with

clinical,

radio-

acid.

The screening logic,

Germany).

we also determined process

laboratory

done

testing.

before

ESWL

Sonography

includes

ofthe

gallbladder

and

biliary

tract is done in addition to a double (reinforcement) dose of OCG to evaluate cystic duct patency and gallbladder function. All 1 74 patients included in the study were candidates for ESWL

using the inclusion general,

and exclusion

a normally

criteria previously

functioning

gallbladder

described

shown

on

[3];

OCGs

in

and

gallstones visible on sonograms were required. Of the 174 patients, 1 12 were women and 62 were men; the patients ranged in age from 17 to 99 years (mean, 50 years). All patients were randomly selected to receive either ursodeoxycholic acid or placebo for 6 months starting 1 week before ESWL. All ESWL procedures were done as previously described [3, 9]. A maximum of one retreatment was allowed and that only for patients who had fragments 5 mm or larger seen on the sonogram 6 weeks after ESWL.

after ESWL and follow-up

6 OCG 6

months after ESWL. At our institution, we added a 6-week the follow-up procedure to assess gallbladder concentrating this OCG was added, only at our institution, after seeing

OCG to ability; several

According

weeks,

to the

3 months,

patients

whose

ders.

protocol,

and 6 months

follow-up

This additional

patients;

in the

all patients

sonograms

6-week

group

OCG

of 25

had

follow-up

showed

contracted

was done

patients

with

sonograms

in 69 (40%)

abnormal

gallblad-

of the 174

gallbladders,

14

patients (56%) had a 6-week OCG. Between 6 weeks and 6 months follow-up, 25 (14%) of the 1 74 patients had faint/nonvisualized gall-

bladders on OCGs and contracted

of

the entire

of stones

group

6 weeks

gallbladders

of 1 74 patients,

after

ESWL.

on sonograms.

only three

All 25 patients

patients

included

were in the

free study

had gallstone fragments at the time of their gallbladder abnormality. All patients were evaluated at the time offollow-up with respect to biliary symptoms; additionally, all patients’ charts were reviewed. Patients not returning for follow-up were contacted by phone to ascertain their clinical status and to determine if they had had a cholecystectomy. The follow-up sonograms were done on a variety of sonography units

3- to 5-MHz transducers,

with

by the Society

of Diagnostic

following

Medical

were told to fast for 12 hr before contracted

gallbladder

shown

food intake and reexamined OCG examinations were schedule

sonography.

by sonography to confirm

published

[1 0]. All patients

All patients

were questioned

the contracted

gallbladder.

with a about All

done by using a 2-day consecutive dose with a total of 1 2 tablets or 6 g of iopanoic acid (Telepaque,

Winthrop

Pharmaceuticals,

instructed

to consume

examination scribed

the guidelines

Sonographers

in the

New York, NY) [1 1]; the patients

a low-fat

diet for 2 days before

and to take the tablets

during

were

the day of the

a 2-day period as do-

instructions.

Results

ET AL.

AJR:159,

with a gallbladder

ESWL had a stone-free gallbladder fragments were present 6 weeks remaining 1 49 patients. 1 2 of the 25 patients

abnormality

after

after treatment. Gallstone after ESWL in 146 of the

For the first 6 months of the study, with gallbladder abnormalities were

1992

taking ursodeoxycholic acid and 1 3 of them were given placebo. The 25 patients were divided into two groups depending on whether or not the abnormalities seen with sonography (contracted gallbladder) or OCG (poor or no visualization) persisted. One patient was lost to follow-up.

A transient

gallbladder

during this 1 2-month faint or no visualization

shown

abnormality

was seen in 18 patients

period. Of these 1 8 patients, six had by OCG and contracted gallbladders

by sonography;

eight

patients

had abnormal

OCG

findings alone and four had sonographic abnormalities only. Of the 18 patients, six with an abnormal gallbladder 6 weeks or 3 months after ESWL had normal sonographic and/or OCG findings at 6 months. At 1 2 months or more after ESWL, 11 of the remaining 1 2 patients had normal findings on sonograms; therefore, 1 7 (94%) of 1 8 patients had a normal gallbladder shown by OCG or sonography at their last followup. One patient was lost to follow-up. Two (1 1 %) of the 18 patients in this group were free of stones 1 2 months after

ESWL. In the ity, three faint or not have patients

seven patients with persistent gallbladder abnormalhad OCG 6 weeks after ESWL by which there was no visualization of the gallbladder; two patients did a 6-week OCG. Cholecystectomy was done in four before the 6-month follow-up, with pathologic diag-

nosis of chronic

cholecystitis

in three and acute cholecystitis

in one; three patients had a cholecystectomy after the 12month period with the pathologic diagnosis of chronic cholecystitis. All seven patients had residual gallstone fragments found during cholecystectomy. Of the 25 patients with abnormal findings on imaging stud-

es after ESWL, the seven patients

(28%) who had persistently

contracted gallbladders all had cholecystectomies. (1 3%) of the 1 49 patients with normal-appearing

shown

by imaging

studies

three of the 1 74 patients ESWL.

underwent were

Twenty gallbladders

cholecystectomy.

free of stones

6 weeks

Only after

Discussion Few studies on changes in gallbladder appearance or function after ESWL have been reported [1-8, 12, 1 3]. In an animal study, histologic examination of gallbladders after lithotripsy showed only minimal changes [14]. Spengler et al.

[1 5] showed that gallbladder motility was not altered after ESWL in patients studied with sonography and cholecystokinin. In a multicenter study, Burnett et al. [8] reported “visualization” in 64 of 67 patients examined with OCG 3 months after ESWL. Rawat reported a 1 2% prevalence of contracted gallbladders shown by sonography in a group of patients after lithotripsy (Rawat B et al., presented at the Third Intemational Symposium on Biliary Lithotripsy, September 1990).

Several investigators None of the 25 patients

August

[1 5-20]

have suggested

that patients

with symptomatic gallstones have impaired gallbladder motility. The cause of the gallbladder motility dysfunction in patients with cholelithiasis is unknown, but it may result from gallstones, chronic inflammation, or stone formation. It has been theorized that gallstone disease with gallbladder fibrosis

AJR:159,

August

GALLBLADDER

1992

and wall thickening malities chronic

ABNORMALITIES

may be involved [1 3]. Although no abnordetected on sonographic examinations,

have been cholecystitis

with

fibrosis

on a histologic

level

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been suggested as the cause of impaired gallbladder ing in patients with symptomatic gallstones.

had

empty-

The potential causes of a contracted gallbladder shown by sonography in our patients are many. It is, however, important to distinguish the physiologically collapsed gallbladder (i.e.,

loss of volume) from a gallbladder of chronic gallbladder disease; tiated on follow-up sonography.

The National sonography

Dornier

to follow

that is contracted this can

Biliary

usually

Lithotripsy

up patients

6 weeks,

because

be difteren-

Study

[5] used

3 months,

and 6

months after ESWL; OCG was used for screening and, subsequently, to evaluate gallbladder function 6 months after ESWL. The 6-week imaging studies revealed a group of patients with

performed contracted

at our center gallbladders

shown by sonography or with a faint or nonfunctioning gallbladder shown by OCG. None of the patients in whom the gallbladder

appeared

contracted

on sonograms

in patients

with

abnormal

gallbladders

after

ESWL,

imaging

studies should be done to assess gallbladder functionsonography or OCG following a fatty meal or with cholecystokinin

can be used.

The seven patients in our study who had persistent gallbladder abnormality all had cholecystectomy; the overall cholecystectomy rate (28%) in our group of 25 patients with gallbladder abnormalities was much higher than the rate (1 3%) in the larger group of 149 patients without gallbladder abnormality after ESWL. We postulate partial or complete obstruction of the cystic duct as a cause of the faint or nonvisualization

bladder shown

of the gallbladder

on sonograms.

mal gallbladders, deoxycholic acid

on OCGs

or the contracted

Of the 25 patients

with abnor-

almost equal numbers were taking ursoor placebo for the first 6 months of the

study; the use or nonuse of bile acids is not thought to be a factor in the contracted or faint/nonvisualized gallbladder after ESWL. The results suggest that in most patients, the abnormal gallbladder after ESWL is a temporary condition-a “stunned gallbladder”-as 17 (68%) of 25 patients had normal findings

The changes

tered ease;

cholecystectomy;

in many of these

patients,

the al-

contractility may result from intrinsic gallbladder disthat is, chronic cholecystitis on a histologic level, not

detectable

by any imaging

method

now available.

327

authors

thank

Faye

Laing,

who

reviewed

and

suggested

to the manuscript.

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on sonograms 12 months or more after ESWL. Those patients with persistently abnormal gallbladders after ESWL often

require

ESWL

ACKNOWLEDGMENT

had a visible

gallbladder on the OCG examination. Conversely, nonvisualization on OCG is not always associated with a contracted gallbladder shown by sonography. We believe that, especially

AFTER

19.

20.

cholecystokinin and contraction of the gallbladder in patients with gallstones. Ann Surg 1982;195:670-675 Forgacs IC, Maisey MN, Murphy GM, Dowling RH. Influence of gallstones and ursodeoxycholic acid therapy on gallbladder emptying. Gastroenterology 1984;87:299-307 Pomeranz IS, Shaffer EA. Abnormal gallbladder emptying in a subgroup of patients with gallstones. Gastroenterology 1985;88:787-791