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393
Color
Doppler
Imaging
Portosystemic
G. Grant1 N. Tessler1 S. Gomes1
Edward
Franklin Antoinette
Chonita L. Holmes1 Rita R. Perrella1 Andre J. Dueninckx1
Ronald
of
Shunts
This study was designed to investigate the utility of color Doppler evaluation of portosystemic shunts. Thirty-one patients with a total imaged. The types of shunts examined included portacaval, five; distal splenorenal(Warren), 14; and mesoatrial, five. Sonography was knowledge of the status of the shunt, although the type of shunt
beginning
the study.
The sonographic
studies
were evaluated
sonography in the of 32 shunts were mesocaval, eight;
performed was
known
to determine
without before
their sensi-
tivity and specificity on the basis of a prospective comparison with angiography or MR imaging (22 cases). The possible advantages of color Doppler over duplex Doppler sonography in evaluating portosystemic shunts were also investigated, as was the ability of color Doppler sonography to image specifically the shunt anastomoses. Color Doppler sonography successfully inferred shunt patency (17 cases) or thrombosis (five cases) in all 22 shunts for which correlative imaging was available (sensitivity = 100%, specificity = 100%). In comparing duplex with color Doppler sonography in all 32 shunts, the two techniques were almost equally effective in establishing patency in portacaval,
W. Busuttil2
mesocaval,
and mesoatrial
shunts.
Duplex
Doppler
sonography,
however,
provided
useful
diagnostic information in only four of 14 splenorenal shunts. Color Doppler correctly inferred patency or thrombosis in all 14. Among all 32 shunts, the anastomosis was shown clearly by color Doppler in 23, probably in four, and not at all in five. Our results suggest that color Doppler sonography is an excellent method for the evaluation of all varieties of surgically created portosystemic shunts. In particular, color Doppler sonography appears to be superior to duplex Doppler sonography in imaging splenorenal communications. AJR
i54:393-397,
February
1990
Portosystemic shunts are constructed to palliate symptomatic portal hypertension [i 2] or to provide decompression of the hepatic vasculatune in patients with Budd-Chiani syndrome [3]. All such shunts may thrombose occasionally, though ,
the frequency
varies
with
the type
of shunt [4, 5]. Acute blockage
shunt may result in a life-threatening recurrence Angiography has been the definitive method for
Received July 1 7, 1 989; accepted September 19, 1989. 1
Department
sity of California,
of Radiological Los Angeles,
after revision
Sciences, Schcol
Univer-
of Medicine,
10833 LeConte Ave., Los Angeles, CA 90024. Address reprint requests to E. G. Grant. 2 Department of Surgery, University Los Angeles,
Schcol
of Medicine,
90024. 0361 -803X/90/1 © American
542-0393
Roentgen
Ray Society
of California,
Los Angeles,
CA
some
time.
However,
angiography
of a portosystemic
of symptoms. of evaluating portosystemic
is invasive,
and
the
anatomically
shunts isolated
portal system may be difficult to opacify [6]. Numerous imaging techniques, including neal-time sonography [7], contrast-enhanced CT [8, 9], and MR imaging [i 0], have been used to evaluate portosystemic shunts noninvasively. Recently, duplex Doppler sonography has been used in this regard as well [9, 1 i -1 6]. The results of evaluations with duplex Doppler sonography have been encouraging, but highly dependent on the location of the shunt [9, 1 i i 5]. We undertook this study to assess the possible role of color Doppler imaging in the evaluation of surgically created portosystemic shunts. ,
Subjects
and Methods
Thirty-two portosystemic Doppler imaging. The ages
shunts in 31 patients were evaluated with color and duplex of the patients at the time of sonographic examination ranged
GRANT
394
from
1 7 to 70 years
were
evaluated.
institution
41
for possible
of
years).
the
Sixteen
31
men
patients
1 5 women
referred
to
as part of their
were
referred
These
disease
primary
patients),
for
of the
processes
alcoholic
liver
of
patients
nontransplantation
venous
Fourteen
shunt
were
portal
patients
patency;
from
three
both
the
pre-
groups. included
biliary cirrhosis
entire
evaluations.
evaluation
1 5 symptomatic and
Underlying
patients),
imaging
preoperative
specifically
transplantation
(six
Doppler
under-
splenorenal flow had
to
shunts to be be visualized
considered in both
patent, limbs of
appropriately directed the shunt (portal vein/
with
duplex
1 4 patients
our
1990
obtained.
system
and
These
and
February
additional shunts were identified on sonograms obtained for other reasons. Fifteen of the 31 patients were symptomatic with ascites or recent gastroesophageal hemorrhage at the time the sonogram was
color
liver transplantation.
were
AJR:154,
inferior vena cava for portacaval, splenic vein/renal vein for splenorenal). For mesoatrial and mesocaval shunts, visualization of appropriately directed flow in any portion of the synthetic graft was taken to imply patency. Sensitivity and specificity were determined by comparing the results of color Doppler sonography with angiography and/or MR imaging. Angiography was performed 1 4 times and MR imaging 1 1 times in a total of 22 patients. Angiography was performed
went
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(mean,
Fourteen
ET AL.
chronic
(six patients),
disease
(six
active
hepatitis
Budd-Chiari
patients),
(10
syndrome
sclerosing
cholan-
standard
gitis (one patient), cystic fibrosis (one patient), and hemochromatosis (one patient). The types of shunts encountered were varied: portacaval (five), mesocaval (eight), distal splenorenal (1 4), and mesoatrial
imaging
(five).
angiography
The
time
sonographic
between
evaluation
color
imaging
where
[15].
in our
construction ranged
initial
of
from
three
1 day
patients
the
shunt
and
the
initial
to 9 years.
The results
have
reported
been
of
else-
studies
were
performed
with
a commercially
available
unit (Ultramark 9, Advanced Technology Laboratories, Bothell, WA). Duplex and color Doppler imaging was performed with phased- and linear-array technology; 2.25-, 3.5-, and 5.0-MHz transducers were used. At the beginning of the examination, the patient’s chart was reviewed
to determine
the
type
of shunt
present.
The
sonologist
did
was considered patent on clinical grounds and had no knowledge of the results of other imaging procedures. The expected area of the shunt was scanned first with duplex Doppler and then with color Doppler imaging. The sonographic studies were then evaluated to address three specific questions: (1 ) What are the sensitivity and specificity of color Doppler sonography in the evaluation of portosystemic shunts? (2) Is color superior to duplex Doppler in assessing portosystemic shunts? (3) Can color Doppler imaging reliably depict shunt anastomoses? not
know
The
if the
criteria
shunt
for inferring
ing on the type
of shunt
shunt
under
patency
varied
investigation.
considerably
depend-
For portacaval
and
Selective
celiac
(and/or
splenic)
and
superior
procedures
were
reviewed
by one
member
of our
group
who
had no knowledge of the results of the sonographic studies. results of the sonograms were then compared with MR imaging Doppler
in a blinded
imaging
The results in all 32
All Doppler
technique.
mesenteric artery injections were performed in all patients. In some cases the shunts were entered directly. Hepatic vein wedge pressures were obtained as indicated. MR imaging was performed with spinecho technique in oblique, axial, and coronal projections. Correlative
fashion.
were based
of duplex
portosystemic
Sensitivity
on the results
vs color
Doppler
shunts.
Duplex
and
specificity were
Doppler
of color
22 shunts.
in these
imaging
The and
then
compared
examinations
were
performed in the usual manner. The shunt was first located, if possible, using real time. The Doppler cursor was then appropriately placed within the shunt and its patency was established on the basis of receiving the expected Doppler signal. A duplex Doppler study was considered unsuccessful if real-time visualization of the shunt (or the limbs of the shunt as described above for color Doppler imaging)
was
insufficient
to allow
adequate
cursor. The ability of color Doppler imaging also was evaluated in all 32 shunts.
placement
to depict
of the
shunt
Doppler
anastomoses
Results Angiography tency
Doppler tency
and/or
in 1 7 of 22
sonognaphy in all
five
i -4).
demonstrated
shunts
successfully
1 7 (Figs.
Fig. 1-Portacaval shunt. A and B, Longitudinal (A ) and transverse (B) color Doppler images show communication between portal vein and inferior vena cava (IVC) (arrows). Considerable turbulence is common at shunt anastomoses, as evidenced by mixture of colors in these areas. During portions of cardiac cycle, blood may reflux into portal system in response to normal phasic flow reversals in ivc. Note red color in portal vein (B); flow is directed toward Doppler beam.
MR imaging
cases;
were
demonstrated
Occlusion
was
shunt
occluded. also
paColor
shunt
pa-
diagnosed
Fig. 2.-Mesoatrial shunt. Longitudinal color Doppler image shows flow within superficial, subcostal portion of mesoatrial shunt. Note brightly echogenic walls of synthetic shunt (arrows). Although flow in shunt is directed toward right atrium, color changes from red to blue as flow advances and recedes in relation to Doppler beam.
AJR:154,
February
COLOR
1990
DOPPLER
OF
correctly in the remaining five (Fig. 5). Specificity and sensitivity, therefore, were 1 00%. These findings are summarized in
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Table
1 . In one
of the
1 7 patients,
a splenorenal
shunt
was
shown to be patent by both sonography and MR imaging. MR imaging, however, showed a narrowing of a small left renal vein as it passed between the superior mesentenic artery and the aorta. At the time of the sonogram, could not be followed as far as the aorta. was
patent,
its function
may
have
been
the left renal vein While this shunt
compromised.
Both
sonography and MR imaging showed the left renal vein to be draining into large retnopenitoneal collatenals. This patient was not symptomatic
at the time
of the
sonogram.
In comparing color and duplex Doppler sonognaphy in all 32 shunts, we found that all portacaval and mesoatrial shunts were adequately evaluated by both techniques. Duplex DoppIer
was
also
successful
mesocaval shunts correctly assessed
Fig. 3.-Mesocaval
in the
evaluation
of seven
(see Fig. 3B). Color Doppler patency in all 1 4 splenonenal
of eight
sonography shunts. Du-
PORTOSYSTEMIC
395
SHUNTS
plex Doppler sonography, however, fulfilled our criteria for a successful study in only four of i 4 splenorenal shunts (Table 2). Among the 32 shunts, the anastomosis was imaged by color Doppler sonography cleanly in 23, probably in four, and not at all in five
(Table
3).
Discussion Sonognaphy has been advocated since 1 977 as a noninvasive method of evaluating portosystemic shunts [6]. Sonognaphy is particularly applicable in acutely ill on uncomfortable patients. In addition, the inherent properties of sonography make it an attractive screening procedure immediately after placement of a shunt or before liven transplantation. Unfortunately, the use of neal-time sonography in the evaluation of portosystemic shunts has been limited, since its anatomically oriented images can only suggest patency. Duplex
shunt.
A, Longitudinal color Doppler image shows superior mesenteric vein (SMV) anterior to synthetic graft (arrow). Color signals are often impossible to demonstrate throughout an entire graft in one image because of changing relationship between flow direction and Doppler beam. B, Patency of mesocaval shunt in another patient is confirmed by showing flow entering distal inferior vena cava (I) from another direction. With persistent scanning, walls of shunt were eventually appreciated (curved arrow). Note posterior acoustic shadowing from graft walls (straight arrows).
Fig. 4.-Distal
splenorenal
shunt.
A, Real-time image from duplex Doppler scan performed via a left anterior approach. No major vessels are identified in expected area of splenic limb of Warren shunt. B, Color Doppler image from same location clearly shows flow in splenic vein (S) coursing toward left renal vein. Anastomosis and left renal vein were imaged by scanning from other vantage points. Duplex Doppler sonography is unsuccessful in these situations.
Fig. 5.-Thrombosis dicated by complete genic walls (arrows).
of mesoatrial absence
shunt is in-
of color within echo-
GRANT
396
TABLE in the
1: Sensitivity and Specificity of Color Evaluation of Portosystemic Shunts
Doppler
Correctly
Angiography/MR
Type of Shunt
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Portacaval Mesoatrial
3 3
Mesocaval
Splenorenal Total
2: Duplex
Portosystemic
Thrombosed
Total
Diagnosed
Imaging
5
1 2 1
4 5 6
4 5 6
6
1
7
7
17
5
22
22
vs Color Doppler
Imaging
of
Duplex
.
Color
5 5 8 14
5 5 7 4
5 5 8 14
Total
32
21
32
3: Ability
of Color Doppler
to Image
Total
Type of Shunt
Shunt
Not
No. 5
4
1
0
Mesoatrial
5
2
3
0
8 14
8 9
0 1
0 4
32
23
5
4
Mesocaval Splenorenal Total
portacaval
Doppler
Colon Doppler shunt
sonognaphy
flow and inferring
was capable
patency
imaging
in all patients.
Sensitivity and specificity were 1 00% in our series. Previous studies of portosystemic shunts using duplex Doppler sonography have found the technique to be relatively accurate. The success of duplex Doppler sonognaphy, however, is largely dependent upon the location of the shunt. Duplex Doppler sonography can image portacaval and mesoatnial
shunts
lien work
quite
in this
adequately.
regard
[i 0, i 2-i
Our study
corroborates
4]. Although
colon
earDoppler
sonognaphy increased confidence and markedly lessened scanning time, it offered no true diagnostic advantage oven duplex Doppler in imaging these two types of shunts. Our results
also
indicate
that
mesocaval
shunts
adequately
imaged
by duplex
Doppler
experience,
real-time
scanning,
in fact,
echogenic
walls of the synthetic
are most
sonography. typically
constructed
less
an accepted
form
sonography,
though
somewhat
better than those of
in the left upper quad-
rant. The color Doppler image was visible through a relative veil of bowel gas and backscatten. Adequate visualization of the splenic and renal limbs of Warren shunts was possible in
investigated.
of directly
vs thrombosis
being
becomes
other hand, was fan more successful
of portosys-
been
are
Foley et al., were still disappointing. The venous limbs of splenonenal shunts were visualized by real time in only four of i 4 cases. Adequate placement of a Doppler cursor, therefore, was not possible. Color Doppler sonognaphy, on the
While color Doppler patency in all patients
in the evaluation
has not, to our knowledge,
vena
are being performed more frequently. Although duplex DoppIer sonography has been relatively successful with mesocaval shunts, the evaluation of distal splenonenal shunts has been problematic. Foley et al. [9], in fact, specifically addressed left upper quadrant shunts and found duplex Doppler sonognaphy thoroughly inadequate. Our results with duplex
technology,
and its potential
shunts
as liver transplantation
all of our patients.
shunts
inferior
duplex Doppler imaging has been considered as a screening procedure for all types of portosystemic a review of the literature reveals that most of the studied had portacaval communications [i i-is].
Doppler sonognaphy, however, provides physiologic flow information and has been used successfully by a number of authors in the evaluation of portosystemic shunts [9, 111 6]. Colon imaging is the latest refinement of sonographic temic
flow in the mid-distal
of therapy for patients with end-stage liven disease and portal hypertension. Mesocaval and splenonenal shunts, therefore,
Anastomoses
Portacaval
area of reversed
Unfortunately,
frequently
Questionable
Imaged
Imaged
1990
case. While potential shunts, patients
Adequate Shunt Visualization
Total
February
cava. As the inferior vena cava has no major infrarenal branches, such flow could only be from the patient’s shunt. Duplex Doppler sonography was not capable of graphically depicting this flow phenomenon and was unsuccessful in this
in the Evaluation
Portacaval Mesoatnial Mesocaval Splenorenal
TABLE
localized
Shunts
Type of Shunt
AJR:154,
Doppler imaged the flow within. Once the graft was located, either color or duplex Doppler sonognaphy could be used to establish patency. Of all shunts, Doppler signals were the most difficult to elicit from within the synthetic walls of mesocaval grafts. In the single mesocaval shunt that was not seen with duplex Doppler sonognaphy, the initial feature identified by colon Doppler sonognaphy was the presence of a
by Color Doppler Patent
TABLE
Imaging
ET AL.
identified
often
In our the
graft more readily than color
brightly
While the thin walls of native veins are not
echogenic,
they
apparently
offer
little
impedance
the transmission of the Doppler beam. The implanted vein is easily located with colon Doppler imaging.
was somewhat
to
splenic
imaging was capable of inferring shunt in our series, the shunt anastomosis
more challenging
to find. As expected,
visibil-
ity varied with the type of shunt being evaluated. The anastomosis between the portal vein and the inferior vena cava was seen readily in almost all patients. The liver provided an
excellent
acoustic
the synthetic shunts was
window mesoatrial
window.
Likewise,
graft and the inferior readily imaged once
was found.
Demonstration
and splenonenal
shunts,
the junction
between
vena cava in mesocaval an appropriate acoustic
of the anastomoses however,
was more
in com-
plicated. In mesoatrial shunts, the junction between the superion mesenteric vein and the graft lies deep within the abdomen. This region is notoriously difficult to evaluate with sonognaphy because of surrounding bowel gas and tenic fat. This situation is probably further worsened high attenuation of the synthetic graft walls. Fortunately, portions of all mesoatrial shunts are easily imaged pass cephalad and come to lie directly beneath the
mesenby the long as they anterior
AJR:154,
February
COLOR
1990
DOPPLER
OF
abdominal wall. In our experience, confirmation of flow within even a small portion of a mesoatnial (or mesocaval) shunt is sufficient
The
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vein
to establish
in Warren
splenic limb of a considerable approach. Left perpendicular left
renal
between shunts
the
may
vein
be difficult
and left renal to image.
The
the shunt usually can be followed dorsally for distance when scanning from a left subcostal renal vein flow, however, is normally directed to the splenic vein. Doppler signals from the
vein,
therefore,
through the left flank. renal veins is optimally points,
the splenic
also
are
Because performed
anastomosis
may
best
received
by
scanning
imaging of the splenic and from two different vantage
be difficult
to image
in a single
section. With experience and meticulous technique, colon Doppler sonography should be capable of visualizing the anastomosis of patent splenonenal shunts in most patients. We have found that scanning the patient when the stomach is empty is particularly helpful. In our patient with a splenorenal shunt and angiognaphically proved thrombosis, the actual site of occlusion was not seen. This is to be expected in splenorenal shunts since the walls of native veins are not sufficiently echogenic to outline the shunt if a color signal is absent. Thrombosis, however, was inferred when a tangle of vessels was found extending from the spleen to large retropenitoneal collaterals. Among these vessels, the splenic limb of the shunt could not be defined as an individual structure. The presence of shunt dysfunction in this patient was particularly obvious since a routine postopenative study 6 weeks earlier showed the typical single vessel
extending
from the splenic
collatenals appearance
were present of collatenals
similar
to that
in the patient
hilum to the left renal vein. No
at the time of the earlier study. in the patient with thrombosis with
suspected
secondary to narrowing of the central basis of these two cases, abnormal
actual thrombosis)
scanning
should be suspected
shunt
The was
dysfunction
left renal vein. On the shunt physiology (or
in any patient with a
splenorenal shunt in whom left upper quadrant collatenals are identified instead of a well-defined splenic limb. Our study has found color Doppler sonography to be an excellent noninvasive method of imaging portosystemic shunts of all varieties. The examination is well tolerated and may even be performed portably, if necessary. While duplex
SHUNTS
offers
portacaval, imaging
patency.
anastomosis
PORTOSYSTEMIC
diagnostic
mesocaval,
more
physiology
rapidly,
increases
evaluation of splenonenal color Doppler sonognaphy
sonography
information
and mesoatrial
is performed
of shunt
397
in most
patients
shunts,
colon Doppler
and anatomic
physician
with
delineation
confidence.
In the
shunts, however, our study shows to be superior to duplex Doppler
and the only adequate
sonognaphic
method
of
evaluation.
REFERENCES 1 . Malt AA. Portasystemic
venous shunts. Part 1 . N EngI J Med 1976;295: 24-29 2. Malt AA. Portasystemic venous shunts. Part 2. N Eng! J Med 1976;295: 80-86 3. Cameron JL, Maddrey WC. Mesoatrial shunt: a new treatment for the Budd-Chiari syndrome. Ann Surg 1978;187:402-406 4. Schwartz SI, ed. Principles of surgery, 3d ed. New York: McGraw-Hill, 1979: 1297-1 315 5. Cameron JL, Kadir 5, Pierce WS. Mesoatrial shunt: a prosthesis modification. Surgery 1984;96:114-116 6. Abrahms HL, ed. Angiography, 2d ed. Boston: Little, Brown, 1971:1073-
1078 7. Goldberg
BB,
Patel
J. tJtrasonic
evaluation
of portacaval
shunts.
JCU
1977;5:304-306 8. Gleysteen JJ, Foley WD, Lawson TL, Unger GF. Patency evaluation distal splenorenal shunt with dynamic computed tomography. col Obstet i982;154:689-694 9. Foley WD, Gleysteen JJ, Lawson TL, et al. Dynamic computed
and pulsed Doppler sonography
in the evaluation
patency.
1983;7:
J Comput
Assist
Tomogr
Surg
of
Gyne-
tomography of spienorenal shunt
106-112
10. Bemardino ME, Steinberg HV, Pearson TC, Gedgaudas-McCIees AK, Torres WE, Henderson JM. Shunts for portal hypertension: MR and angiography for determination of patency. Radiology 1986;158:57-61 11. Ackroyd N, Gill A, Griffiths K, Kossoff G, Reeve T. Duplex scanning of the portal vein and portasystemic
shunts.
Surgery
1986;99:591-597
12. Finn JP, Gibson AN, Dunn GD. Duplex ultrasound in the evaluation of portacaval shunts. Clln Radio! 1987;38:87-89 13. Forsberg L, Holmin T. Pulsed Doppler and B-mode ultrasound features of interposition meso-caval and porta-caval shunts. Acta Radio! (Diagn] (Stockh) i983;24:353-357 14. Lafortune M, Patnquin H, Pomier G, et al. Hemodynamic changes in portal circulation after portosystemic patients. AJR i987;149:701-706
shunts:
use of duplex
sonography
in 43
15. Patriquin H, Lafortune M, Weber A, Blanchard H, Garel L, Roy C. Surgical portosystemic shunts in children: assessment with duplex Doppler US. Radio!ogy
1987;165:25-28
16. Grant EG, Perreila A, Tessler FN, Lois J, Busuttil A. Budd-Chiari syndrome: the results of duplex and color Doppler imaging. AJR i989;1 52:377-381
393
Color
Doppler
Imaging
Portosystemic
G. Grant1 N. Tessler1 S. Gomes1
Edward
Franklin Antoinette
Chonita L. Holmes1 Rita R. Perrella1 Andre J. Dueninckx1
Ronald
of
Shunts
This study was designed to investigate the utility of color Doppler evaluation of portosystemic shunts. Thirty-one patients with a total imaged. The types of shunts examined included portacaval, five; distal splenorenal(Warren), 14; and mesoatrial, five. Sonography was knowledge of the status of the shunt, although the type of shunt
beginning
the study.
The sonographic
studies
were evaluated
sonography in the of 32 shunts were mesocaval, eight;
performed was
known
to determine
without before
their sensi-
tivity and specificity on the basis of a prospective comparison with angiography or MR imaging (22 cases). The possible advantages of color Doppler over duplex Doppler sonography in evaluating portosystemic shunts were also investigated, as was the ability of color Doppler sonography to image specifically the shunt anastomoses. Color Doppler sonography successfully inferred shunt patency (17 cases) or thrombosis (five cases) in all 22 shunts for which correlative imaging was available (sensitivity = 100%, specificity = 100%). In comparing duplex with color Doppler sonography in all 32 shunts, the two techniques were almost equally effective in establishing patency in portacaval,
W. Busuttil2
mesocaval,
and mesoatrial
shunts.
Duplex
Doppler
sonography,
however,
provided
useful
diagnostic information in only four of 14 splenorenal shunts. Color Doppler correctly inferred patency or thrombosis in all 14. Among all 32 shunts, the anastomosis was shown clearly by color Doppler in 23, probably in four, and not at all in five. Our results suggest that color Doppler sonography is an excellent method for the evaluation of all varieties of surgically created portosystemic shunts. In particular, color Doppler sonography appears to be superior to duplex Doppler sonography in imaging splenorenal communications. AJR
i54:393-397,
February
1990
Portosystemic shunts are constructed to palliate symptomatic portal hypertension [i 2] or to provide decompression of the hepatic vasculatune in patients with Budd-Chiani syndrome [3]. All such shunts may thrombose occasionally, though ,
the frequency
varies
with
the type
of shunt [4, 5]. Acute blockage
shunt may result in a life-threatening recurrence Angiography has been the definitive method for
Received July 1 7, 1 989; accepted September 19, 1989. 1
Department
sity of California,
of Radiological Los Angeles,
after revision
Sciences, Schcol
Univer-
of Medicine,
10833 LeConte Ave., Los Angeles, CA 90024. Address reprint requests to E. G. Grant. 2 Department of Surgery, University Los Angeles,
Schcol
of Medicine,
90024. 0361 -803X/90/1 © American
542-0393
Roentgen
Ray Society
of California,
Los Angeles,
CA
some
time.
However,
angiography
of a portosystemic
of symptoms. of evaluating portosystemic
is invasive,
and
the
anatomically
shunts isolated
portal system may be difficult to opacify [6]. Numerous imaging techniques, including neal-time sonography [7], contrast-enhanced CT [8, 9], and MR imaging [i 0], have been used to evaluate portosystemic shunts noninvasively. Recently, duplex Doppler sonography has been used in this regard as well [9, 1 i -1 6]. The results of evaluations with duplex Doppler sonography have been encouraging, but highly dependent on the location of the shunt [9, 1 i i 5]. We undertook this study to assess the possible role of color Doppler imaging in the evaluation of surgically created portosystemic shunts. ,
Subjects
and Methods
Thirty-two portosystemic Doppler imaging. The ages
shunts in 31 patients were evaluated with color and duplex of the patients at the time of sonographic examination ranged
GRANT
394
from
1 7 to 70 years
were
evaluated.
institution
41
for possible
of
years).
the
Sixteen
31
men
patients
1 5 women
referred
to
as part of their
were
referred
These
disease
primary
patients),
for
of the
processes
alcoholic
liver
of
patients
nontransplantation
venous
Fourteen
shunt
were
portal
patients
patency;
from
three
both
the
pre-
groups. included
biliary cirrhosis
entire
evaluations.
evaluation
1 5 symptomatic and
Underlying
patients),
imaging
preoperative
specifically
transplantation
(six
Doppler
under-
splenorenal flow had
to
shunts to be be visualized
considered in both
patent, limbs of
appropriately directed the shunt (portal vein/
with
duplex
1 4 patients
our
1990
obtained.
system
and
These
and
February
additional shunts were identified on sonograms obtained for other reasons. Fifteen of the 31 patients were symptomatic with ascites or recent gastroesophageal hemorrhage at the time the sonogram was
color
liver transplantation.
were
AJR:154,
inferior vena cava for portacaval, splenic vein/renal vein for splenorenal). For mesoatrial and mesocaval shunts, visualization of appropriately directed flow in any portion of the synthetic graft was taken to imply patency. Sensitivity and specificity were determined by comparing the results of color Doppler sonography with angiography and/or MR imaging. Angiography was performed 1 4 times and MR imaging 1 1 times in a total of 22 patients. Angiography was performed
went
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(mean,
Fourteen
ET AL.
chronic
(six patients),
disease
(six
active
hepatitis
Budd-Chiari
patients),
(10
syndrome
sclerosing
cholan-
standard
gitis (one patient), cystic fibrosis (one patient), and hemochromatosis (one patient). The types of shunts encountered were varied: portacaval (five), mesocaval (eight), distal splenorenal (1 4), and mesoatrial
imaging
(five).
angiography
The
time
sonographic
between
evaluation
color
imaging
where
[15].
in our
construction ranged
initial
of
from
three
1 day
patients
the
shunt
and
the
initial
to 9 years.
The results
have
reported
been
of
else-
studies
were
performed
with
a commercially
available
unit (Ultramark 9, Advanced Technology Laboratories, Bothell, WA). Duplex and color Doppler imaging was performed with phased- and linear-array technology; 2.25-, 3.5-, and 5.0-MHz transducers were used. At the beginning of the examination, the patient’s chart was reviewed
to determine
the
type
of shunt
present.
The
sonologist
did
was considered patent on clinical grounds and had no knowledge of the results of other imaging procedures. The expected area of the shunt was scanned first with duplex Doppler and then with color Doppler imaging. The sonographic studies were then evaluated to address three specific questions: (1 ) What are the sensitivity and specificity of color Doppler sonography in the evaluation of portosystemic shunts? (2) Is color superior to duplex Doppler in assessing portosystemic shunts? (3) Can color Doppler imaging reliably depict shunt anastomoses? not
know
The
if the
criteria
shunt
for inferring
ing on the type
of shunt
shunt
under
patency
varied
investigation.
considerably
depend-
For portacaval
and
Selective
celiac
(and/or
splenic)
and
superior
procedures
were
reviewed
by one
member
of our
group
who
had no knowledge of the results of the sonographic studies. results of the sonograms were then compared with MR imaging Doppler
in a blinded
imaging
The results in all 32
All Doppler
technique.
mesenteric artery injections were performed in all patients. In some cases the shunts were entered directly. Hepatic vein wedge pressures were obtained as indicated. MR imaging was performed with spinecho technique in oblique, axial, and coronal projections. Correlative
fashion.
were based
of duplex
portosystemic
Sensitivity
on the results
vs color
Doppler
shunts.
Duplex
and
specificity were
Doppler
of color
22 shunts.
in these
imaging
The and
then
compared
examinations
were
performed in the usual manner. The shunt was first located, if possible, using real time. The Doppler cursor was then appropriately placed within the shunt and its patency was established on the basis of receiving the expected Doppler signal. A duplex Doppler study was considered unsuccessful if real-time visualization of the shunt (or the limbs of the shunt as described above for color Doppler imaging)
was
insufficient
to allow
adequate
cursor. The ability of color Doppler imaging also was evaluated in all 32 shunts.
placement
to depict
of the
shunt
Doppler
anastomoses
Results Angiography tency
Doppler tency
and/or
in 1 7 of 22
sonognaphy in all
five
i -4).
demonstrated
shunts
successfully
1 7 (Figs.
Fig. 1-Portacaval shunt. A and B, Longitudinal (A ) and transverse (B) color Doppler images show communication between portal vein and inferior vena cava (IVC) (arrows). Considerable turbulence is common at shunt anastomoses, as evidenced by mixture of colors in these areas. During portions of cardiac cycle, blood may reflux into portal system in response to normal phasic flow reversals in ivc. Note red color in portal vein (B); flow is directed toward Doppler beam.
MR imaging
cases;
were
demonstrated
Occlusion
was
shunt
occluded. also
paColor
shunt
pa-
diagnosed
Fig. 2.-Mesoatrial shunt. Longitudinal color Doppler image shows flow within superficial, subcostal portion of mesoatrial shunt. Note brightly echogenic walls of synthetic shunt (arrows). Although flow in shunt is directed toward right atrium, color changes from red to blue as flow advances and recedes in relation to Doppler beam.
AJR:154,
February
COLOR
1990
DOPPLER
OF
correctly in the remaining five (Fig. 5). Specificity and sensitivity, therefore, were 1 00%. These findings are summarized in
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Table
1 . In one
of the
1 7 patients,
a splenorenal
shunt
was
shown to be patent by both sonography and MR imaging. MR imaging, however, showed a narrowing of a small left renal vein as it passed between the superior mesentenic artery and the aorta. At the time of the sonogram, could not be followed as far as the aorta. was
patent,
its function
may
have
been
the left renal vein While this shunt
compromised.
Both
sonography and MR imaging showed the left renal vein to be draining into large retnopenitoneal collatenals. This patient was not symptomatic
at the time
of the
sonogram.
In comparing color and duplex Doppler sonognaphy in all 32 shunts, we found that all portacaval and mesoatrial shunts were adequately evaluated by both techniques. Duplex DoppIer
was
also
successful
mesocaval shunts correctly assessed
Fig. 3.-Mesocaval
in the
evaluation
of seven
(see Fig. 3B). Color Doppler patency in all 1 4 splenonenal
of eight
sonography shunts. Du-
PORTOSYSTEMIC
395
SHUNTS
plex Doppler sonography, however, fulfilled our criteria for a successful study in only four of i 4 splenorenal shunts (Table 2). Among the 32 shunts, the anastomosis was imaged by color Doppler sonography cleanly in 23, probably in four, and not at all in five
(Table
3).
Discussion Sonognaphy has been advocated since 1 977 as a noninvasive method of evaluating portosystemic shunts [6]. Sonognaphy is particularly applicable in acutely ill on uncomfortable patients. In addition, the inherent properties of sonography make it an attractive screening procedure immediately after placement of a shunt or before liven transplantation. Unfortunately, the use of neal-time sonography in the evaluation of portosystemic shunts has been limited, since its anatomically oriented images can only suggest patency. Duplex
shunt.
A, Longitudinal color Doppler image shows superior mesenteric vein (SMV) anterior to synthetic graft (arrow). Color signals are often impossible to demonstrate throughout an entire graft in one image because of changing relationship between flow direction and Doppler beam. B, Patency of mesocaval shunt in another patient is confirmed by showing flow entering distal inferior vena cava (I) from another direction. With persistent scanning, walls of shunt were eventually appreciated (curved arrow). Note posterior acoustic shadowing from graft walls (straight arrows).
Fig. 4.-Distal
splenorenal
shunt.
A, Real-time image from duplex Doppler scan performed via a left anterior approach. No major vessels are identified in expected area of splenic limb of Warren shunt. B, Color Doppler image from same location clearly shows flow in splenic vein (S) coursing toward left renal vein. Anastomosis and left renal vein were imaged by scanning from other vantage points. Duplex Doppler sonography is unsuccessful in these situations.
Fig. 5.-Thrombosis dicated by complete genic walls (arrows).
of mesoatrial absence
shunt is in-
of color within echo-
GRANT
396
TABLE in the
1: Sensitivity and Specificity of Color Evaluation of Portosystemic Shunts
Doppler
Correctly
Angiography/MR
Type of Shunt
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Portacaval Mesoatrial
3 3
Mesocaval
Splenorenal Total
2: Duplex
Portosystemic
Thrombosed
Total
Diagnosed
Imaging
5
1 2 1
4 5 6
4 5 6
6
1
7
7
17
5
22
22
vs Color Doppler
Imaging
of
Duplex
.
Color
5 5 8 14
5 5 7 4
5 5 8 14
Total
32
21
32
3: Ability
of Color Doppler
to Image
Total
Type of Shunt
Shunt
Not
No. 5
4
1
0
Mesoatrial
5
2
3
0
8 14
8 9
0 1
0 4
32
23
5
4
Mesocaval Splenorenal Total
portacaval
Doppler
Colon Doppler shunt
sonognaphy
flow and inferring
was capable
patency
imaging
in all patients.
Sensitivity and specificity were 1 00% in our series. Previous studies of portosystemic shunts using duplex Doppler sonography have found the technique to be relatively accurate. The success of duplex Doppler sonognaphy, however, is largely dependent upon the location of the shunt. Duplex Doppler sonography can image portacaval and mesoatnial
shunts
lien work
quite
in this
adequately.
regard
[i 0, i 2-i
Our study
corroborates
4]. Although
colon
earDoppler
sonognaphy increased confidence and markedly lessened scanning time, it offered no true diagnostic advantage oven duplex Doppler in imaging these two types of shunts. Our results
also
indicate
that
mesocaval
shunts
adequately
imaged
by duplex
Doppler
experience,
real-time
scanning,
in fact,
echogenic
walls of the synthetic
are most
sonography. typically
constructed
less
an accepted
form
sonography,
though
somewhat
better than those of
in the left upper quad-
rant. The color Doppler image was visible through a relative veil of bowel gas and backscatten. Adequate visualization of the splenic and renal limbs of Warren shunts was possible in
investigated.
of directly
vs thrombosis
being
becomes
other hand, was fan more successful
of portosys-
been
are
Foley et al., were still disappointing. The venous limbs of splenonenal shunts were visualized by real time in only four of i 4 cases. Adequate placement of a Doppler cursor, therefore, was not possible. Color Doppler sonognaphy, on the
While color Doppler patency in all patients
in the evaluation
has not, to our knowledge,
vena
are being performed more frequently. Although duplex DoppIer sonography has been relatively successful with mesocaval shunts, the evaluation of distal splenonenal shunts has been problematic. Foley et al. [9], in fact, specifically addressed left upper quadrant shunts and found duplex Doppler sonognaphy thoroughly inadequate. Our results with duplex
technology,
and its potential
shunts
as liver transplantation
all of our patients.
shunts
inferior
duplex Doppler imaging has been considered as a screening procedure for all types of portosystemic a review of the literature reveals that most of the studied had portacaval communications [i i-is].
Doppler sonognaphy, however, provides physiologic flow information and has been used successfully by a number of authors in the evaluation of portosystemic shunts [9, 111 6]. Colon imaging is the latest refinement of sonographic temic
flow in the mid-distal
of therapy for patients with end-stage liven disease and portal hypertension. Mesocaval and splenonenal shunts, therefore,
Anastomoses
Portacaval
area of reversed
Unfortunately,
frequently
Questionable
Imaged
Imaged
1990
case. While potential shunts, patients
Adequate Shunt Visualization
Total
February
cava. As the inferior vena cava has no major infrarenal branches, such flow could only be from the patient’s shunt. Duplex Doppler sonography was not capable of graphically depicting this flow phenomenon and was unsuccessful in this
in the Evaluation
Portacaval Mesoatnial Mesocaval Splenorenal
TABLE
localized
Shunts
Type of Shunt
AJR:154,
Doppler imaged the flow within. Once the graft was located, either color or duplex Doppler sonognaphy could be used to establish patency. Of all shunts, Doppler signals were the most difficult to elicit from within the synthetic walls of mesocaval grafts. In the single mesocaval shunt that was not seen with duplex Doppler sonognaphy, the initial feature identified by colon Doppler sonognaphy was the presence of a
by Color Doppler Patent
TABLE
Imaging
ET AL.
identified
often
In our the
graft more readily than color
brightly
While the thin walls of native veins are not
echogenic,
they
apparently
offer
little
impedance
the transmission of the Doppler beam. The implanted vein is easily located with colon Doppler imaging.
was somewhat
to
splenic
imaging was capable of inferring shunt in our series, the shunt anastomosis
more challenging
to find. As expected,
visibil-
ity varied with the type of shunt being evaluated. The anastomosis between the portal vein and the inferior vena cava was seen readily in almost all patients. The liver provided an
excellent
acoustic
the synthetic shunts was
window mesoatrial
window.
Likewise,
graft and the inferior readily imaged once
was found.
Demonstration
and splenonenal
shunts,
the junction
between
vena cava in mesocaval an appropriate acoustic
of the anastomoses however,
was more
in com-
plicated. In mesoatrial shunts, the junction between the superion mesenteric vein and the graft lies deep within the abdomen. This region is notoriously difficult to evaluate with sonognaphy because of surrounding bowel gas and tenic fat. This situation is probably further worsened high attenuation of the synthetic graft walls. Fortunately, portions of all mesoatrial shunts are easily imaged pass cephalad and come to lie directly beneath the
mesenby the long as they anterior
AJR:154,
February
COLOR
1990
DOPPLER
OF
abdominal wall. In our experience, confirmation of flow within even a small portion of a mesoatnial (or mesocaval) shunt is sufficient
The
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vein
to establish
in Warren
splenic limb of a considerable approach. Left perpendicular left
renal
between shunts
the
may
vein
be difficult
and left renal to image.
The
the shunt usually can be followed dorsally for distance when scanning from a left subcostal renal vein flow, however, is normally directed to the splenic vein. Doppler signals from the
vein,
therefore,
through the left flank. renal veins is optimally points,
the splenic
also
are
Because performed
anastomosis
may
best
received
by
scanning
imaging of the splenic and from two different vantage
be difficult
to image
in a single
section. With experience and meticulous technique, colon Doppler sonography should be capable of visualizing the anastomosis of patent splenonenal shunts in most patients. We have found that scanning the patient when the stomach is empty is particularly helpful. In our patient with a splenorenal shunt and angiognaphically proved thrombosis, the actual site of occlusion was not seen. This is to be expected in splenorenal shunts since the walls of native veins are not sufficiently echogenic to outline the shunt if a color signal is absent. Thrombosis, however, was inferred when a tangle of vessels was found extending from the spleen to large retropenitoneal collaterals. Among these vessels, the splenic limb of the shunt could not be defined as an individual structure. The presence of shunt dysfunction in this patient was particularly obvious since a routine postopenative study 6 weeks earlier showed the typical single vessel
extending
from the splenic
collatenals appearance
were present of collatenals
similar
to that
in the patient
hilum to the left renal vein. No
at the time of the earlier study. in the patient with thrombosis with
suspected
secondary to narrowing of the central basis of these two cases, abnormal
actual thrombosis)
scanning
should be suspected
shunt
The was
dysfunction
left renal vein. On the shunt physiology (or
in any patient with a
splenorenal shunt in whom left upper quadrant collatenals are identified instead of a well-defined splenic limb. Our study has found color Doppler sonography to be an excellent noninvasive method of imaging portosystemic shunts of all varieties. The examination is well tolerated and may even be performed portably, if necessary. While duplex
SHUNTS
offers
portacaval, imaging
patency.
anastomosis
PORTOSYSTEMIC
diagnostic
mesocaval,
more
physiology
rapidly,
increases
evaluation of splenonenal color Doppler sonognaphy
sonography
information
and mesoatrial
is performed
of shunt
397
in most
patients
shunts,
colon Doppler
and anatomic
physician
with
delineation
confidence.
In the
shunts, however, our study shows to be superior to duplex Doppler
and the only adequate
sonognaphic
method
of
evaluation.
REFERENCES 1 . Malt AA. Portasystemic
venous shunts. Part 1 . N EngI J Med 1976;295: 24-29 2. Malt AA. Portasystemic venous shunts. Part 2. N Eng! J Med 1976;295: 80-86 3. Cameron JL, Maddrey WC. Mesoatrial shunt: a new treatment for the Budd-Chiari syndrome. Ann Surg 1978;187:402-406 4. Schwartz SI, ed. Principles of surgery, 3d ed. New York: McGraw-Hill, 1979: 1297-1 315 5. Cameron JL, Kadir 5, Pierce WS. Mesoatrial shunt: a prosthesis modification. Surgery 1984;96:114-116 6. Abrahms HL, ed. Angiography, 2d ed. Boston: Little, Brown, 1971:1073-
1078 7. Goldberg
BB,
Patel
J. tJtrasonic
evaluation
of portacaval
shunts.
JCU
1977;5:304-306 8. Gleysteen JJ, Foley WD, Lawson TL, Unger GF. Patency evaluation distal splenorenal shunt with dynamic computed tomography. col Obstet i982;154:689-694 9. Foley WD, Gleysteen JJ, Lawson TL, et al. Dynamic computed
and pulsed Doppler sonography
in the evaluation
patency.
1983;7:
J Comput
Assist
Tomogr
Surg
of
Gyne-
tomography of spienorenal shunt
106-112
10. Bemardino ME, Steinberg HV, Pearson TC, Gedgaudas-McCIees AK, Torres WE, Henderson JM. Shunts for portal hypertension: MR and angiography for determination of patency. Radiology 1986;158:57-61 11. Ackroyd N, Gill A, Griffiths K, Kossoff G, Reeve T. Duplex scanning of the portal vein and portasystemic
shunts.
Surgery
1986;99:591-597
12. Finn JP, Gibson AN, Dunn GD. Duplex ultrasound in the evaluation of portacaval shunts. Clln Radio! 1987;38:87-89 13. Forsberg L, Holmin T. Pulsed Doppler and B-mode ultrasound features of interposition meso-caval and porta-caval shunts. Acta Radio! (Diagn] (Stockh) i983;24:353-357 14. Lafortune M, Patnquin H, Pomier G, et al. Hemodynamic changes in portal circulation after portosystemic patients. AJR i987;149:701-706
shunts:
use of duplex
sonography
in 43
15. Patriquin H, Lafortune M, Weber A, Blanchard H, Garel L, Roy C. Surgical portosystemic shunts in children: assessment with duplex Doppler US. Radio!ogy
1987;165:25-28
16. Grant EG, Perreila A, Tessler FN, Lois J, Busuttil A. Budd-Chiari syndrome: the results of duplex and color Doppler imaging. AJR i989;1 52:377-381
