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997
Changes in Extrahepatic Bile Duct Caliber in Liver Transplant Recipients Without Evidence of Biliary Obstruction
Wilbiarn
To better
Richard
transplantation, duct on serial
L. Carnpbebb1 G. Foster1’2 Wilbiarn J. Miller1
Jarnes
W. Lecky1
Albert B. Zajk& Kyung Y. Lee3
understand
dochostomy
changes
in the
we retrospectively chobangiograms
studied
size
of the extrahepatic
the luminal
in 40 liver transplant
bibiary anastomoses
bile duct
after
of the extrahepatic
recipients
with
and without biliary complications.
liver
bile
choledochochole-
Forty operative
and
The average interval between oper5 weeks (range, 1-17 weeks). The
105 postoperative cholangiograms were reviewed. ative and last postoperative cholangiogram was
mean diameter ± 2.4 mm (p =
diameter
of the donor common hepatic duct increased from 5.5 ± 2. 1 mm to 6.3 The mean diameter of the native common bile duct increased from
.015).
5.1 ± 1.4 mm to 6.8 ± 2.4 mm (p < .001). The diameter of the donor common hepatic increased by 3 mm or more in six patients (15%); the diameter of the native common bile duct increased by 3 mm or more in nine (23%). Increased diameter of the native common bile duct was associated with T-tube migration into the duct in four cases. The size of the extrahepatic bile duct on cholangiograms is stable or increases slightly in most liver transplant recipients. Mild increases unassociated with a specific cause of obstruction or hepatic dysfunction do not portend biliary obstruction and are clinically duct
benign. AJR
Bibiary
obstruction
transplants. biliary tree, obstruction
Received October 15, 1991 ; accepted December 18, 1991.
after
re-
vision I
Department
of Radiology,
lkiiversity
of Pitts-
burgh School of Medicine, Presbyterian University Hospital, DeSoto at O’Hara Sts., Pittsburgh, PA
1 521 3. Address reprint requests to W. L. Campbell. 2 Present address: Department of Radiology, West burgh,
Penn
Hospital,
4800
Friendship
Ave.,
0361 -803X/92/1 C American
Graduate Pittsburgh,
585-0997 Ray Society
Roentgen
1992
after
Causes
include
liver
transplantation
strictures
occurs
in approximately
at the bibiary anastomosis
5%
of
or in the donor [1 2]. Apparent
retained internal stents, T-tube problems, and stones at the ampubba of Vater with diffuse dilatation of the recipient and donor bile ducts and hepatic dysfunction also has been described. In such ,
extrahepatic cases, chobangiography shows biliary dilatation or other specific cause for obstruction [3, 4].
without
Although unexplained
clue to the presence of obstruction, of the recipient and donor extrahe-
biliary dilatation is often a valuable increases in the luminal diameters
evidence
of stricture,
stone,
patic bile ducts occasionally develop in liver transplant recipients who apparently do not have obstruction. Documentation of such acquired changes would have implications for the imaging diagnosis of posttransplantation obstructive biliary dilatation and, possibly, for the understanding of pathophysiobogic changes that might accompany choledochochobedochostomy biliary reconstructions. We therefore studied the size of the extrahepatic bile duct on serial cholangiograms in liver transplant obstruction.
recipients
who
had no clinical
or pathologic
evidence
of biliary
Pitts-
PA 15224.
3Department of Biostatistics, of Public Health, University of burgh, PA 15213.
May
158:997-1000,
School Pitts-
Materials
and Methods
Complete imaging transplant recipients
data and clinical follow-up were available for 49 consecutive liver who had postoperative cholangiography between January and July
1 988. Nine of these were excluded from the study because required biliary anastomotic revision to a choledochojejunostomy
of biliary complications with Roux-en-Y
that
loop. Forty
998
CAMPBELL
patients,
22
men
and
18
Mean age was 45 years structions
of
the
women,
made
(range,
end-to-end
1 8-71
up
the
years).
final
study
ET AL.
AJA:i58,
May 1992
group.
All had biliary
choledochocholedochostomy
recon(duct-to-
type with a T-tube left in place. For each patient, a good quality operative cholangiogram and at least one postoperative cholangiogram were available for review. None of the patients was considered to have biliary obstruction on the basis of clinical, laboratory, or liver biopsy evidence; none had subsequent surgical revision oftheir biliary
Downloaded from www.ajronline.org by 186.216.250.73 on 10/11/15 from IP address 186.216.250.73. Copyright ARRS. For personal use only; all rights reserved
duct)
reconstructions. Operative
and
postoperative
T-tube
formed by hand injection of 25% made
to standardize
cholangiograms
overhead
rate
on
Operative
target-to-film
per-
conventional
spot
films
and
one
by using a 44-in. (1 .1 m) target-to-
cholangiography
distance.
was
No attempt was Postoperative T-tube
diatrizoate.
of injection.
recorded
tube Bucky radiograph
film distance. 44-in.
the
were
cholangiography
sodium
was performed
Percutaneous
by using
transhepatic
a
cholangi-
was performed in the standard fashion with a 40-in. (1 m)
ography
target-to-film distance. The caliber of the extrahepatic bile duct was measured on Bucky overhead or spot film radiographs. The least magnified views that exhibited good duct filling were selected for review. For the purposes of this study, good duct filling consisted of complete distension of the extrahepatic bile ducts, as determined from several radiographs, accompanied
by flow
intrahepatic
duct
into
the duodenum
branches.
was made. Correction
and
No absolute
filling
of multiple
Correction
for magnification
tertiary
for magnification
of spot radiographs
relative
to overhead operative and postoperative radiographs was made by measuring the lengths of the intraductal T portions of the T-tubes on anteroposterior projections. The difference between the spot and overhead
radiograph
measurement
measurements
gave
the
compared
with overhead
diameters
measured
direct
comparison
donor
common
midway caliber
of the
the
films to the nearest
overhead
hepatic
duct
the duct
native
by
overhead
of magnification
film
of spot
films
was
bifurcation
common
millimeter
radiographs.
measured and
bile duct
was
The
at a point
the biliary
of
anastomosis;
measured
at the
the
precisely the midpoint
for each patient by comparing the operative cholangiogram with both the postoperative study that showed the greatest diameter and the last available postoperative cholangiogram. The last postoperative Statistical
t-tests,
study
analyses
was
were
Mann-Whitney
Fig. 1.-Increase in diameter of extrahepatic bile duct after uncomplicated liver transplantation. A, Operative cholangiogram shows diameters of 4 mm for donor common hepatic duct and 3 mm for native common bile duct. Arrow = anastomosis. B, T-tube cholangiogram obtained 3 months later shows diameters of 5 mm for donor common hepatic and 6 mm for native common bile duct. Arrow = anastomosis.
to allow
caliber
between the anastomosis and the sphincter of Oddi. Changes in diameter of the extrahepatic bile ducts were calculated
cholangiographic
B
films. This factor was used to correct duct
on spot with
between
divided
percentage
A
used
for
performed
statistical
by using
U, and Pearson correlation
comparisons.
paired
and
unpaired
tests [5].
mm); the mean caliber on the last postoperative cholangiogram was 6.3 ± 2.4 mm (range, 2-1 1 mm). The increase from 5.5 to 6.3 mm was significant (p = .01 5). The mean
caliber of the native common giograms
caliber
was
5.1
±
bile duct on operative
1 .4 mm
(range,
on the last postoperative
2-8
mm);
cholangiogram
2.4 mm (range, 3-1 3 mm). The was statistically significant (p < the donor common hepatic duct in six (1 5%) of 40 patients, by 2
native
Results
had migrated
increase from 5.1 to 6.8 mm .001) (Fig. 1). The caliber of increased by 3 mm or more mm in 1 0 (25%), by 1 mm in
common
bile
to the sphincter
duct,
was not filled. The diameter One hundred forty-five cholangiograms were reviewed, in40 operative and 1 04 postoperative T-tube studies. One postoperative percutaneous transhepatic study was percluding
formed
after T-tube
removab. The mean number
of postoper-
ative cholangiograms The average interval erative cholangiogram
per transplant was 2.5 (range, 1-5). between the operative and last postopwas 5 weeks (range, 1 -1 7 weeks).
The average
of clinical
(range,
patients
0.3-33.5
length
months),
of 29.6 months
the
mean
was 6.8 ±
five (1 2%), and by 0 mm in 18 (45%); in one patient the T-tube
chobanthe
donor
of Oddi common
in whom
in a dilated hepatic
of the native common
duct
bile duct
increased by 3 mm or more in nine patients (22%), by 2 mm in 1 0 (25%), by 1 mm in eight (20%), and by 0 mm in 13 (32%). In three patients, the diameter of the native common bile duct was 1 2 mm or more on the last cholangiogram (12
mm in two patients and 13 mm in one). Increases in duct diameter in these three cases were 5, 8, and 9 mm. There
with
a mean
follow-up
in living
were no significant differences between changes in bile duct size calculated using the postoperative chobangiogram with the greatest duct diameter and the last postoperative cholan-
(range,
27-33.5
months).
Thirteen
giogram.
follow-up
was 21 .6 months
patients (33%) died between 0.3 and 1 8.2 (mean, 5.0) months after transplantation. The mean caliber of the donor common hepatic duct on operative cholangiograms was 5.5 ± 2.1 mm (range, 2-10
subsequently
No
patients
In four patients, tube
developed
significant
dilatation
that
resolved.
had migrated
In one of these,
the last cholangiogram into the distal
showed
common
the tube had passed
that the T-
bile duct
(Fig. 2).
into the sphincter
of
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AJR:i58,
CHANGES
May 1992
Fig. 2.-Marked
increase
in diameter
of extrahepatic
IN EXTRAHEPATIC
duct associated
with T-tube migration in a liver transplant recipient. A, Operative cholangiogram shows diameters of 3 mm for donor cornmon hepatic duct and 4 mm for native common bile duct. Arrow = area of anastomosis. B, T-tube cholangiogram performed 2 months, 22 days later shows an
increase in diameter of common ducts. Diameter of donor common hepatic duct is 7 mm, and diameter of native common bile duct is 12 mm. T-tube has migrated
into distal
common
bile duct. Arrow
= anastomosis.
Oddi and in another it had just reached the sphincter. The mean diameter of the donor common hepatiC duct in these patients was 7.7 ± 1 .2 mm, compared with 6.2 ± 2.5 mm in patients without tube migration (p = .232). The mean diameter of the native common bile duct was 1 1 .0 ± 1 .8 mm, compared with 6.4 ± 1 .9 mm in patients without tube migration (p = .002). The mean increase in diameter of the native common bile duct in the four patients with tube migration was 6.0 ± 2.9 mm, compared with 1 .25 ± 1 .7 mm in the other subjects (p = .002). The increase in the diameter of the donor common hepatic duct was 2.3 ± 1 .5 mm in patients with tube migration compared with 0.6 ± 1 .9 mm in those without migration (p = .140). In 36 patients without tube migration, the mean size of the donor common hepatic duct increased from 5.6 ± 2.1 mm to 6.2 ± 2.5 mm (p = .047). The mean size of the native common bile duct increased from 5.1 ± 1 .4 mm to 6.4 ± 1 .9 mm (p < .001). We found no correlation between increasing size of the native common bile duct and either the age or sex of the patient.
Discussion Imaging of the extrahepatic bile ducts is a routine part of the postoperative management of liver transplant recipients. Early diagnosis of biliary complications such as obstruction or bile leak is essential for prompt treatment. An increase in
BILE
DUCT
CALIBER
999
the diameter of the bile duct may be an important clue to biliary obstruction in liver transplant recipients, as it may be in nontransplantation patients. This is particularly true in the diagnosis of so-called obstructive diffuse dilatation or ampullary obstruction, for which the main cholangiographic finding is dilatation of the extrahepatic bile ducts [4]. Although it has been assumed that the diameter of the extrahepatic bile duct normally remains stable in liver transplant recipients, occasionally both donor and native extrahepatic bile ducts have increased in size over time. Some cases, usually with more marked dilatation, have been associated with hepatic dysfunction that has improved with revision of the biliary anastomosis to a choledochojejunostomy [3, 4]. In other cases, the increase in the diameter of the bile duct has appeared to be clinically benign. The results of this study indicate that a slight increase in the size of the extrahepatic bile duct shown on cholangiograms is not unusual in liver transplant recipients, and in some patients, dilatation of the extrahepatic bile ducts develops. These findings have implications for the interpretation of posttranspbantation cholangiograms and, perhaps, for a better understanding of patients with clinically significant diffuse biliary dilatation and hepatic dysfunction. Although the degree of duct filling and radiographic magnification may affect measurements of bile duct caliber on cholangiograms, it is unlikely that the increases seen in the study patients can be entirely explained on this basis. Operative cholangiograms showed good duct distension, as evidenced by the extent of intrahepatic duct filling and the presence of flow into the duodenum; indeed, the degree of filling often was greater than in the postoperative studies. Chance variation in injection pressure could not account for observed increases in duct size as increases in diameter were statistically significant and progressive on serial studies. We corrected for magnification on spot films compared with operative and nonoperative overhead films by using the intraductal portion of the T-tube as an internal standard. Mean relative spot film magnification was 8% (range, 0-39%). As a practical matter, spot film magnification accounted for no more than 2 mm of apparent increase in duct size in any of the study patients. Whenever possible, we compared films taken in similar projections, although differences in patients’ positions have a negligible influence on radiographic magnification of the extrahepatic bile ducts [6]. We analyzed change in the size of the extrahepatic bile ducts by using both the postoperative study that showed the greatest diameter (perhaps representing greatest distention or most magnification) and the last available cholangiogram; there was no significant difference between the two. For the calculation and statistical analysis of changes in diameter, we used the more conservative last examination figure to minimize any artifactuab increase in measurement. The explanation for increases in the size of the extrahepatic bile duct in liver transplant recipients is not entirely clear. Possible mechanisms include increased function of the extrahepatic bile ducts as a reservoir in the absence of a gallbladder, variations in underlying duct laxity, and subclinical lowgrade obstruction. The prevalence of an acquired increase in caliber in the study patients is higher than has been reported
1000
CAMPBELL
in nontransplantation
barly those
studied
postcholecystectomy patients, particuwith sonography [7-9]. Liver transplant
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recipients are unusual in that they may have a number of postoperative cholangiograms over several weeks or months, even in the absence of evidence of biliary obstruction; com-
parable serial cholangiographic nontransplantation
ally lacking.
observations
postcholecystectomy
Direct cholangiography
in uncomplicated patients
distends
are gener-
the bile ducts,
ET AL.
had T-tube
migration.
duct
between
sizes
complications
or otherwise
careful hepatic
nign. Occasionally,
sometimes significant
into the increases
into the distal
common
bile duct
ampulba of Vater was associated in the size of the native common
duct (3, 4, 8, and 9 mm in four patients).
and
The largest percent-
tubes in liver transplant recipients is not infrequent and is more common than in nontransplantation patients. Factors prompting tube migration may include small-caliber pliable tubes, excess intraabdominal tube length, and increasing duct diameter. Whether acquired duct dilatation usually precedes tube migration is not entirely clear, but a tube folded on itself in the native common bile duct and sometimes in the ampulla
of Vater seems in some cases to lead to further dilatation of the native segment of the common bile duct. Clinical obstruction is not usually a problem, and the T-tubes are normally removed without incident within 2-3 months of the transplantation. One must consider whether some patients with slight increases in the diameter of the extrahepatic bile duct may eventually have obstructive bibiary dilatation with hepatic dysfunction. Although this must happen occasionally, the patients obstruction
to do well without
2.5 years after transplantation.
dilatation
with
hepatic
dysfunction
evidence Diffuse
of biliary
obstructive
is nearly
recipients
unexplained
exists
without
without
hepatic
in
clinically
biliary
dysfunction
suggest
clinical
larger increases
in duct size (to 1 2 mm or
ampublary
obstruction.
In managing
such patients,
attention must be paid to the diameter of the extrabile duct on baseline operative cholangiograms, re-
tests and liver biopsies,
and the overall
picture.
with bile
ages of increase in size of the native common bile duct occurred in two patients with tube migration. Migration of T-
in this study continued
and
some associated with T-tube migration, overlap with of obstructive extrahepatic biliary dilatation and may
suits of liver function migration
some overlap with
creases in duct caliber occur in the first few weeks or months after transplantation and are usually slight and clinically be-
setting and is not likely to be a factor [1 0]. T-tube clamping after transplantation might influence the time of development of increases in duct caliber, but data on this variable are not T-tube
groups
May 1992
may have increases in the size of both native and donor extrahepatic bile ducts on postoperative cholangiograms. In-
greater), findings
available.
Nevertheless, the
apparent biliary obstruction. In summary, some liver transplant
which in part explains the well-known disparity between cholangiographic and sonographic results but does not explain progressive increases in size. Dilatation forced by excessive injection pressure probably does not occur in the clinical
biliary
AJR:i58,
always
characterized by increases in the diameter of extrahepatic ducts on cholangiograms to 1 2 mm or more (uncorrected for magnification)[4]. In contrast, the diameter of either the native
or the donor extrahepatic duct increased to 12 mm or more (uncorrected for magnification) and would have been considered dilated in only five patients in this study, two of whom
ACKNOWLEDGMENTS We thank Gloria Stephenson aration.
and Paula Kraft for manuscript
prep-
REFERENCES 1 . Zajko AB, Bron KM, Campbell WL, Behal R, Van Thiel DH, Starzl TE. Percutaneous transhepatic cholangiography and biliary drainage after liver transplantation: a five year experience. Gastrointest Radiol 1987;12: 137-143
2. Lerut J, Gordon AD, Iwatsuki 5, et al. Biliary tract complications
3.
in human
orthotopic liver transplantation. Transplantation 1987;43:47-5i Stieber AC, Ambrosino G, Kahn D, et al. An unusual complication
of
choledochocholedochostomy
in orthotopic liver transplantation. Transplant Proc 1988;20[suppl 1]:619-621 4. Miller WJ, Campbell WL, Zajko AB, et al. Obstructive dilatation of extrahepatic reolpient and donor bile ducts complicating orthotopic liver transplantation: imaging and laboratory findings. AJR 1991;157:29-32 5. Steele A, Tome J. Principles and procedures of statistics. New York:
McGraw-Hill,
1960
6. Persson B, Olsson J. Variations of common bile duct diameter after endoscopic sphincterotomy. Gastrointest Radiol 1991;16:45-48 7. Graham MF, Cooperberg PL, Cohen MM, Burhenne HJ. The size of the normal common hepatic duct following cholecystectomy: an ultrasonographic study. Radiology 1980;135: 137-1 39 8. Mueller PA, Ferrucci JT Jr, Simeone JF, et al. Postcholecystectomy bile duct dilatation: myth or reality? AJR 1981;136:355-358 9. Hunt DA, Scott AJ. Changes in bile duct diameter after cholecystectomy: a 5-year prospective study. Gastroenterology 1989;97 :1485-1488 10. Zeman AK, Burrell Ml. Gallbladder and bile duct imaging: a clinical radiologic approach. New York: Churchill Livingstone, 1987:403
997
Changes in Extrahepatic Bile Duct Caliber in Liver Transplant Recipients Without Evidence of Biliary Obstruction
Wilbiarn
To better
Richard
transplantation, duct on serial
L. Carnpbebb1 G. Foster1’2 Wilbiarn J. Miller1
Jarnes
W. Lecky1
Albert B. Zajk& Kyung Y. Lee3
understand
dochostomy
changes
in the
we retrospectively chobangiograms
studied
size
of the extrahepatic
the luminal
in 40 liver transplant
bibiary anastomoses
bile duct
after
of the extrahepatic
recipients
with
and without biliary complications.
liver
bile
choledochochole-
Forty operative
and
The average interval between oper5 weeks (range, 1-17 weeks). The
105 postoperative cholangiograms were reviewed. ative and last postoperative cholangiogram was
mean diameter ± 2.4 mm (p =
diameter
of the donor common hepatic duct increased from 5.5 ± 2. 1 mm to 6.3 The mean diameter of the native common bile duct increased from
.015).
5.1 ± 1.4 mm to 6.8 ± 2.4 mm (p < .001). The diameter of the donor common hepatic increased by 3 mm or more in six patients (15%); the diameter of the native common bile duct increased by 3 mm or more in nine (23%). Increased diameter of the native common bile duct was associated with T-tube migration into the duct in four cases. The size of the extrahepatic bile duct on cholangiograms is stable or increases slightly in most liver transplant recipients. Mild increases unassociated with a specific cause of obstruction or hepatic dysfunction do not portend biliary obstruction and are clinically duct
benign. AJR
Bibiary
obstruction
transplants. biliary tree, obstruction
Received October 15, 1991 ; accepted December 18, 1991.
after
re-
vision I
Department
of Radiology,
lkiiversity
of Pitts-
burgh School of Medicine, Presbyterian University Hospital, DeSoto at O’Hara Sts., Pittsburgh, PA
1 521 3. Address reprint requests to W. L. Campbell. 2 Present address: Department of Radiology, West burgh,
Penn
Hospital,
4800
Friendship
Ave.,
0361 -803X/92/1 C American
Graduate Pittsburgh,
585-0997 Ray Society
Roentgen
1992
after
Causes
include
liver
transplantation
strictures
occurs
in approximately
at the bibiary anastomosis
5%
of
or in the donor [1 2]. Apparent
retained internal stents, T-tube problems, and stones at the ampubba of Vater with diffuse dilatation of the recipient and donor bile ducts and hepatic dysfunction also has been described. In such ,
extrahepatic cases, chobangiography shows biliary dilatation or other specific cause for obstruction [3, 4].
without
Although unexplained
clue to the presence of obstruction, of the recipient and donor extrahe-
biliary dilatation is often a valuable increases in the luminal diameters
evidence
of stricture,
stone,
patic bile ducts occasionally develop in liver transplant recipients who apparently do not have obstruction. Documentation of such acquired changes would have implications for the imaging diagnosis of posttransplantation obstructive biliary dilatation and, possibly, for the understanding of pathophysiobogic changes that might accompany choledochochobedochostomy biliary reconstructions. We therefore studied the size of the extrahepatic bile duct on serial cholangiograms in liver transplant obstruction.
recipients
who
had no clinical
or pathologic
evidence
of biliary
Pitts-
PA 15224.
3Department of Biostatistics, of Public Health, University of burgh, PA 15213.
May
158:997-1000,
School Pitts-
Materials
and Methods
Complete imaging transplant recipients
data and clinical follow-up were available for 49 consecutive liver who had postoperative cholangiography between January and July
1 988. Nine of these were excluded from the study because required biliary anastomotic revision to a choledochojejunostomy
of biliary complications with Roux-en-Y
that
loop. Forty
998
CAMPBELL
patients,
22
men
and
18
Mean age was 45 years structions
of
the
women,
made
(range,
end-to-end
1 8-71
up
the
years).
final
study
ET AL.
AJA:i58,
May 1992
group.
All had biliary
choledochocholedochostomy
recon(duct-to-
type with a T-tube left in place. For each patient, a good quality operative cholangiogram and at least one postoperative cholangiogram were available for review. None of the patients was considered to have biliary obstruction on the basis of clinical, laboratory, or liver biopsy evidence; none had subsequent surgical revision oftheir biliary
Downloaded from www.ajronline.org by 186.216.250.73 on 10/11/15 from IP address 186.216.250.73. Copyright ARRS. For personal use only; all rights reserved
duct)
reconstructions. Operative
and
postoperative
T-tube
formed by hand injection of 25% made
to standardize
cholangiograms
overhead
rate
on
Operative
target-to-film
per-
conventional
spot
films
and
one
by using a 44-in. (1 .1 m) target-to-
cholangiography
distance.
was
No attempt was Postoperative T-tube
diatrizoate.
of injection.
recorded
tube Bucky radiograph
film distance. 44-in.
the
were
cholangiography
sodium
was performed
Percutaneous
by using
transhepatic
a
cholangi-
was performed in the standard fashion with a 40-in. (1 m)
ography
target-to-film distance. The caliber of the extrahepatic bile duct was measured on Bucky overhead or spot film radiographs. The least magnified views that exhibited good duct filling were selected for review. For the purposes of this study, good duct filling consisted of complete distension of the extrahepatic bile ducts, as determined from several radiographs, accompanied
by flow
intrahepatic
duct
into
the duodenum
branches.
was made. Correction
and
No absolute
filling
of multiple
Correction
for magnification
tertiary
for magnification
of spot radiographs
relative
to overhead operative and postoperative radiographs was made by measuring the lengths of the intraductal T portions of the T-tubes on anteroposterior projections. The difference between the spot and overhead
radiograph
measurement
measurements
gave
the
compared
with overhead
diameters
measured
direct
comparison
donor
common
midway caliber
of the
the
films to the nearest
overhead
hepatic
duct
the duct
native
by
overhead
of magnification
film
of spot
films
was
bifurcation
common
millimeter
radiographs.
measured and
bile duct
was
The
at a point
the biliary
of
anastomosis;
measured
at the
the
precisely the midpoint
for each patient by comparing the operative cholangiogram with both the postoperative study that showed the greatest diameter and the last available postoperative cholangiogram. The last postoperative Statistical
t-tests,
study
analyses
was
were
Mann-Whitney
Fig. 1.-Increase in diameter of extrahepatic bile duct after uncomplicated liver transplantation. A, Operative cholangiogram shows diameters of 4 mm for donor common hepatic duct and 3 mm for native common bile duct. Arrow = anastomosis. B, T-tube cholangiogram obtained 3 months later shows diameters of 5 mm for donor common hepatic and 6 mm for native common bile duct. Arrow = anastomosis.
to allow
caliber
between the anastomosis and the sphincter of Oddi. Changes in diameter of the extrahepatic bile ducts were calculated
cholangiographic
B
films. This factor was used to correct duct
on spot with
between
divided
percentage
A
used
for
performed
statistical
by using
U, and Pearson correlation
comparisons.
paired
and
unpaired
tests [5].
mm); the mean caliber on the last postoperative cholangiogram was 6.3 ± 2.4 mm (range, 2-1 1 mm). The increase from 5.5 to 6.3 mm was significant (p = .01 5). The mean
caliber of the native common giograms
caliber
was
5.1
±
bile duct on operative
1 .4 mm
(range,
on the last postoperative
2-8
mm);
cholangiogram
2.4 mm (range, 3-1 3 mm). The was statistically significant (p < the donor common hepatic duct in six (1 5%) of 40 patients, by 2
native
Results
had migrated
increase from 5.1 to 6.8 mm .001) (Fig. 1). The caliber of increased by 3 mm or more mm in 1 0 (25%), by 1 mm in
common
bile
to the sphincter
duct,
was not filled. The diameter One hundred forty-five cholangiograms were reviewed, in40 operative and 1 04 postoperative T-tube studies. One postoperative percutaneous transhepatic study was percluding
formed
after T-tube
removab. The mean number
of postoper-
ative cholangiograms The average interval erative cholangiogram
per transplant was 2.5 (range, 1-5). between the operative and last postopwas 5 weeks (range, 1 -1 7 weeks).
The average
of clinical
(range,
patients
0.3-33.5
length
months),
of 29.6 months
the
mean
was 6.8 ±
five (1 2%), and by 0 mm in 18 (45%); in one patient the T-tube
chobanthe
donor
of Oddi common
in whom
in a dilated hepatic
of the native common
duct
bile duct
increased by 3 mm or more in nine patients (22%), by 2 mm in 1 0 (25%), by 1 mm in eight (20%), and by 0 mm in 13 (32%). In three patients, the diameter of the native common bile duct was 1 2 mm or more on the last cholangiogram (12
mm in two patients and 13 mm in one). Increases in duct diameter in these three cases were 5, 8, and 9 mm. There
with
a mean
follow-up
in living
were no significant differences between changes in bile duct size calculated using the postoperative chobangiogram with the greatest duct diameter and the last postoperative cholan-
(range,
27-33.5
months).
Thirteen
giogram.
follow-up
was 21 .6 months
patients (33%) died between 0.3 and 1 8.2 (mean, 5.0) months after transplantation. The mean caliber of the donor common hepatic duct on operative cholangiograms was 5.5 ± 2.1 mm (range, 2-10
subsequently
No
patients
In four patients, tube
developed
significant
dilatation
that
resolved.
had migrated
In one of these,
the last cholangiogram into the distal
showed
common
the tube had passed
that the T-
bile duct
(Fig. 2).
into the sphincter
of
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AJR:i58,
CHANGES
May 1992
Fig. 2.-Marked
increase
in diameter
of extrahepatic
IN EXTRAHEPATIC
duct associated
with T-tube migration in a liver transplant recipient. A, Operative cholangiogram shows diameters of 3 mm for donor cornmon hepatic duct and 4 mm for native common bile duct. Arrow = area of anastomosis. B, T-tube cholangiogram performed 2 months, 22 days later shows an
increase in diameter of common ducts. Diameter of donor common hepatic duct is 7 mm, and diameter of native common bile duct is 12 mm. T-tube has migrated
into distal
common
bile duct. Arrow
= anastomosis.
Oddi and in another it had just reached the sphincter. The mean diameter of the donor common hepatiC duct in these patients was 7.7 ± 1 .2 mm, compared with 6.2 ± 2.5 mm in patients without tube migration (p = .232). The mean diameter of the native common bile duct was 1 1 .0 ± 1 .8 mm, compared with 6.4 ± 1 .9 mm in patients without tube migration (p = .002). The mean increase in diameter of the native common bile duct in the four patients with tube migration was 6.0 ± 2.9 mm, compared with 1 .25 ± 1 .7 mm in the other subjects (p = .002). The increase in the diameter of the donor common hepatic duct was 2.3 ± 1 .5 mm in patients with tube migration compared with 0.6 ± 1 .9 mm in those without migration (p = .140). In 36 patients without tube migration, the mean size of the donor common hepatic duct increased from 5.6 ± 2.1 mm to 6.2 ± 2.5 mm (p = .047). The mean size of the native common bile duct increased from 5.1 ± 1 .4 mm to 6.4 ± 1 .9 mm (p < .001). We found no correlation between increasing size of the native common bile duct and either the age or sex of the patient.
Discussion Imaging of the extrahepatic bile ducts is a routine part of the postoperative management of liver transplant recipients. Early diagnosis of biliary complications such as obstruction or bile leak is essential for prompt treatment. An increase in
BILE
DUCT
CALIBER
999
the diameter of the bile duct may be an important clue to biliary obstruction in liver transplant recipients, as it may be in nontransplantation patients. This is particularly true in the diagnosis of so-called obstructive diffuse dilatation or ampullary obstruction, for which the main cholangiographic finding is dilatation of the extrahepatic bile ducts [4]. Although it has been assumed that the diameter of the extrahepatic bile duct normally remains stable in liver transplant recipients, occasionally both donor and native extrahepatic bile ducts have increased in size over time. Some cases, usually with more marked dilatation, have been associated with hepatic dysfunction that has improved with revision of the biliary anastomosis to a choledochojejunostomy [3, 4]. In other cases, the increase in the diameter of the bile duct has appeared to be clinically benign. The results of this study indicate that a slight increase in the size of the extrahepatic bile duct shown on cholangiograms is not unusual in liver transplant recipients, and in some patients, dilatation of the extrahepatic bile ducts develops. These findings have implications for the interpretation of posttranspbantation cholangiograms and, perhaps, for a better understanding of patients with clinically significant diffuse biliary dilatation and hepatic dysfunction. Although the degree of duct filling and radiographic magnification may affect measurements of bile duct caliber on cholangiograms, it is unlikely that the increases seen in the study patients can be entirely explained on this basis. Operative cholangiograms showed good duct distension, as evidenced by the extent of intrahepatic duct filling and the presence of flow into the duodenum; indeed, the degree of filling often was greater than in the postoperative studies. Chance variation in injection pressure could not account for observed increases in duct size as increases in diameter were statistically significant and progressive on serial studies. We corrected for magnification on spot films compared with operative and nonoperative overhead films by using the intraductal portion of the T-tube as an internal standard. Mean relative spot film magnification was 8% (range, 0-39%). As a practical matter, spot film magnification accounted for no more than 2 mm of apparent increase in duct size in any of the study patients. Whenever possible, we compared films taken in similar projections, although differences in patients’ positions have a negligible influence on radiographic magnification of the extrahepatic bile ducts [6]. We analyzed change in the size of the extrahepatic bile ducts by using both the postoperative study that showed the greatest diameter (perhaps representing greatest distention or most magnification) and the last available cholangiogram; there was no significant difference between the two. For the calculation and statistical analysis of changes in diameter, we used the more conservative last examination figure to minimize any artifactuab increase in measurement. The explanation for increases in the size of the extrahepatic bile duct in liver transplant recipients is not entirely clear. Possible mechanisms include increased function of the extrahepatic bile ducts as a reservoir in the absence of a gallbladder, variations in underlying duct laxity, and subclinical lowgrade obstruction. The prevalence of an acquired increase in caliber in the study patients is higher than has been reported
1000
CAMPBELL
in nontransplantation
barly those
studied
postcholecystectomy patients, particuwith sonography [7-9]. Liver transplant
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recipients are unusual in that they may have a number of postoperative cholangiograms over several weeks or months, even in the absence of evidence of biliary obstruction; com-
parable serial cholangiographic nontransplantation
ally lacking.
observations
postcholecystectomy
Direct cholangiography
in uncomplicated patients
distends
are gener-
the bile ducts,
ET AL.
had T-tube
migration.
duct
between
sizes
complications
or otherwise
careful hepatic
nign. Occasionally,
sometimes significant
into the increases
into the distal
common
bile duct
ampulba of Vater was associated in the size of the native common
duct (3, 4, 8, and 9 mm in four patients).
and
The largest percent-
tubes in liver transplant recipients is not infrequent and is more common than in nontransplantation patients. Factors prompting tube migration may include small-caliber pliable tubes, excess intraabdominal tube length, and increasing duct diameter. Whether acquired duct dilatation usually precedes tube migration is not entirely clear, but a tube folded on itself in the native common bile duct and sometimes in the ampulla
of Vater seems in some cases to lead to further dilatation of the native segment of the common bile duct. Clinical obstruction is not usually a problem, and the T-tubes are normally removed without incident within 2-3 months of the transplantation. One must consider whether some patients with slight increases in the diameter of the extrahepatic bile duct may eventually have obstructive bibiary dilatation with hepatic dysfunction. Although this must happen occasionally, the patients obstruction
to do well without
2.5 years after transplantation.
dilatation
with
hepatic
dysfunction
evidence Diffuse
of biliary
obstructive
is nearly
recipients
unexplained
exists
without
without
hepatic
in
clinically
biliary
dysfunction
suggest
clinical
larger increases
in duct size (to 1 2 mm or
ampublary
obstruction.
In managing
such patients,
attention must be paid to the diameter of the extrabile duct on baseline operative cholangiograms, re-
tests and liver biopsies,
and the overall
picture.
with bile
ages of increase in size of the native common bile duct occurred in two patients with tube migration. Migration of T-
in this study continued
and
some associated with T-tube migration, overlap with of obstructive extrahepatic biliary dilatation and may
suits of liver function migration
some overlap with
creases in duct caliber occur in the first few weeks or months after transplantation and are usually slight and clinically be-
setting and is not likely to be a factor [1 0]. T-tube clamping after transplantation might influence the time of development of increases in duct caliber, but data on this variable are not T-tube
groups
May 1992
may have increases in the size of both native and donor extrahepatic bile ducts on postoperative cholangiograms. In-
greater), findings
available.
Nevertheless, the
apparent biliary obstruction. In summary, some liver transplant
which in part explains the well-known disparity between cholangiographic and sonographic results but does not explain progressive increases in size. Dilatation forced by excessive injection pressure probably does not occur in the clinical
biliary
AJR:i58,
always
characterized by increases in the diameter of extrahepatic ducts on cholangiograms to 1 2 mm or more (uncorrected for magnification)[4]. In contrast, the diameter of either the native
or the donor extrahepatic duct increased to 12 mm or more (uncorrected for magnification) and would have been considered dilated in only five patients in this study, two of whom
ACKNOWLEDGMENTS We thank Gloria Stephenson aration.
and Paula Kraft for manuscript
prep-
REFERENCES 1 . Zajko AB, Bron KM, Campbell WL, Behal R, Van Thiel DH, Starzl TE. Percutaneous transhepatic cholangiography and biliary drainage after liver transplantation: a five year experience. Gastrointest Radiol 1987;12: 137-143
2. Lerut J, Gordon AD, Iwatsuki 5, et al. Biliary tract complications
3.
in human
orthotopic liver transplantation. Transplantation 1987;43:47-5i Stieber AC, Ambrosino G, Kahn D, et al. An unusual complication
of
choledochocholedochostomy
in orthotopic liver transplantation. Transplant Proc 1988;20[suppl 1]:619-621 4. Miller WJ, Campbell WL, Zajko AB, et al. Obstructive dilatation of extrahepatic reolpient and donor bile ducts complicating orthotopic liver transplantation: imaging and laboratory findings. AJR 1991;157:29-32 5. Steele A, Tome J. Principles and procedures of statistics. New York:
McGraw-Hill,
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6. Persson B, Olsson J. Variations of common bile duct diameter after endoscopic sphincterotomy. Gastrointest Radiol 1991;16:45-48 7. Graham MF, Cooperberg PL, Cohen MM, Burhenne HJ. The size of the normal common hepatic duct following cholecystectomy: an ultrasonographic study. Radiology 1980;135: 137-1 39 8. Mueller PA, Ferrucci JT Jr, Simeone JF, et al. Postcholecystectomy bile duct dilatation: myth or reality? AJR 1981;136:355-358 9. Hunt DA, Scott AJ. Changes in bile duct diameter after cholecystectomy: a 5-year prospective study. Gastroenterology 1989;97 :1485-1488 10. Zeman AK, Burrell Ml. Gallbladder and bile duct imaging: a clinical radiologic approach. New York: Churchill Livingstone, 1987:403
