ct signs of fugal portal venous flow in patients with cirrhosis

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AJR:181, December 2003 1629

CT Signs of Hepatofugal PortalVenous Flow in Patients with Cirrhosis

OBJECTIVE. We investigated whether CT signs can be used to predict hepatofugal flow

in the main portal vein in patients with cirrhosis.

MATERIALS AND METHODS. We retrospectively identified 36 patients with cirrho-

sis, 18 with hepatopetal and 18 with hepatofugal flow in the main portal vein, who underwent

contemporaneous abdominal sonography and CT. Two independent observers evaluated the

following features on the randomized CT studies: diameter of the portal, splenic, and superior

mesenteric veins; spleen size; and the presence of ascites, varices, or arterial phase portalvenous enhancement. These data were correlated with the flow direction seen on sonography.

RESULTS.

A small main portal vein was the only sign significantly (

p

≤

0.05) predictive

of hepatofugal flow by univariate and multivariate analyses. Observers 1 and 2 recorded a

portal vein diameter of less than 1 cm in eight (44%) and seven (39%) of the 18 patients with

hepatofugal flow compared with one (6%) and none of the 18 patients with hepatopetal flow,

respectively (

p

< 0.02). Receiver operating characteristic analysis using the size of the portal

vein to predict flow direction revealed an area under the curve of 0.83 for observer 1 and 0.74

for observer 2.

CONCLUSION.

A diameter of less than 1 cm for the main portal vein is highly specific,

although not sensitive, for hepatofugal portal venous flow in patients with cirrhosis. This sign

may be useful when sonography is limited, or this sign may prompt sonographic assessment

in patients not known to have hepatofugal flow.

epatofugal portal venous flow in

patients with cirrhosis indicates

advanced portal hypertension

[1], and cirrhotic patients with hepatofugal

flow have greater hepatic dysfunction [2], a

higher incidence of hepatic encephalopathy

[3], an increased risk of variceal bleeding

[2, 4, 5], poorer response of varices to endo-

scopic ligation [6], and higher mortality [2,

7], compared with cirrhotic patients with

hepatopetal flow. The detection of hepatofu-

gal flow in the main portal vein implies the

liver is perfused solely by the hepatic artery,

which is of therapeutic importance in plan-ning chemoembolization of a hepatocellular

carcinoma or placement of a transjugular in-

trahepatic portosystemic shunt (TIPS). CT

arterioportography and portal venous an-

giography may be ineffective and therefore

contraindicated in the presence of hepatofu-

gal portal venous flow [8]. Doppler sonogra-

phy is the principal technique used to

determine the direction of flow in the portal

vein [9, 10], although MRI [11–13] and con-

ventional angiography [14, 15] can also be

used. To our knowledge, the role of CT in

determining the direction of portal venous

flow has not been systematically examined,

although patients with cirrhosis frequently

undergo CT, particularly when hepatocellu-

lar carcinoma is a concern. The establish-

ment of CT criteria for the detection of

hepatofugal flow in the main portal vein

could be helpful in the evaluation of such pa-

tients. Therefore, we undertook this study to

determine whether CT signs can be used to

predict hepatofugal portal venous flow in pa-tients with cirrhosis.

Materials and Methods

Patients

This study was a retrospective single-institution

study approved by our institutional review board.

Informed consent was not required. We searched

our radiology information system (IDXrad [soft-

ware version 9.7.1], IDX Systems, Burlington, VT)

Thomas J. Bryce

1

Benjamin M. Yeh

1

Aliya Qayyum

1

Preeyacha Pacharn

2

Nathan M. Bass

3

Ying Lu

1

Fergus V. Coakley

1

Received April 10, 2003; accepted after revisionJune 26, 2003.

1

Department of Medicine and Department of Radiology,Abdominal Imaging Section, University of California at SanFrancisco, Box 0628, 505 Parnassus Ave., San Francisco,

CA 94143-0628. Address correspondence toF. V. Coakley ([email protected]).

2

Department of Radiology, Mahidol University, 2 PrannokRd., Bangkok, 10700 Thailand.

3

Department of Medicine, Division of Gastroenterology,University of California at San Francisco, Box 0538, 505Parnassus Ave., San Francisco, CA 94143-0538.

AJR

2003;181:1629–1633

0361–803X/03/1816–1629

© American Roentgen Ray Society

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1630

AJR:181, December 2003

Bryce et al.

and medical records for the period of October 1998

to March 2002 to identify patients meeting the fol-

lowing sequential criteria: abdominal sonography

report containing the term “cirrhosis”; contempora-

neous (within 5 months) abdominal CT; direction

of flow in the main portal vein described in the

sonography report; absence of TIPS or thrombosis

of the main portal vein; and histologic diagnosis of cirrhosis (

n

= 11) or a clear clinical diagnosis of

cirrhosis documented in the medical record (

n

=

25). We identified 18 patients with hepatofugal

flow in the main portal vein who met these criteria.

We then randomly selected an additional 18 pa-

tients with hepatopetal flow who also met these cri-

teria to form the final study population of 36

patients. None of the patients was assigned a

Child-Pugh class because not all required data

were available retrospectively.

The mean age of patients in the hepatopetal

group was 59 years (range, 44–80 years) versus 51

years (range, 17–73 years) in the hepatofugal

group. The hepatopetal group comprised 10 men

and eight women, and the hepatofugal group com-

prised seven men and 11 women. In the hepato-

petal group, the diagnosis of cirrhosis was

established by histology in six patients and on

clinical grounds in 12; in the hepatofugal group,

cirrhosis was established by histology in five pa-

tients and on clinical grounds in 13. Of those pa-

tients without histologic confirmation, cirrhosis

was diagnosed by a gastroenterologist in all but

two, both of whom had hepatofugal portal venous

flow. In these two patients, cirrhosis was diag-

nosed on the basis of clinical evidence including a

history of severe alcohol abuse; gross findings of

cirrhosis on imaging studies; and large varices, as-

cites, hypoalbuminemia, and coagulopathy. The

causes for cirrhosis in the group with hepatopetal

flow and in the group with hepatofugal flow, re-spectively, included the following: chronic viral

hepatitis, 11 and four patients; viral hepatitis and

ethanol abuse, two patients and one patient; etha-

nol abuse alone, 0 and six patients; autoimmune

hepatitis, one and three patients; nonalcoholic ste-

atotic hepatitis, one patient and 0 patients; primary

sclerosing cholangitis, one and three patients; and

cystic fibrosis, 0 and one patient. Cirrhosis was

cryptogenic in two patients with hepatopetal flow.

The median time between sonography and CT

was 23 days (range, 0–148 days) in the hepato-

petal group and 3 days (range, 0–97 days) in the

hepatofugal group. If sonography had been per-

formed more than 48 hr before or after the CT ex-

amination (hepatopetal group

, n

= 14; hepatofugalgroup, n

= 9), we identified a second Doppler

sonographic study of flow direction in the main

portal vein for each patient so that sonography oc-

curred before and after the CT examination

(hepatopetal group

, n

= 9; hepatofugal group, n

=

5). Alternatively, if CT had not been performed be-

tween the sonographic examinations, we identified

the two sonographic examinations closest in time

to the CT examination (hepatopetal group

, n

= 2;

hepatofugal group, n

= 2). In these patients, the

time lag between CT and sonography for the two

patients with hepatopetal flow was 3 and 31 days,

and for the two patients with hepatofugal flow, the

lag was 37 and 62 days. Additional studies were

not available for the remaining three hepatopetal

and two hepatofugal patients. All additional sono-

graphic studies evaluated confirmed the flow di-

rection seen on the initial study.

Imaging Technique

All CT examinations were performed on mul-

tidetector scanners (LightSpeed or HiSpeed, Gen-

eral Electric Medical Systems, Milwaukee, WI).

Thirty-four of the 36 patients received 150 mL of

IV iohexol (Omnipaque 350, Nycomed Amersham,

Princeton, NJ), and images were acquired in the

portal venous phase of enhancement (70-sec scan

delay with 5-mm slice collimation). Images were

also acquired in the arterial phase of enhancement

(45-sec scan delay with 2.5-mm slice collimation)

in 20 of these patients. Two patients (one with

hepatopetal and one with hepatofugal flow) did not

receive IV contrast material. All patients received

oral diatrizoate meglumine (Hypaque, Nycomed

Amersham). All images were contiguous. Color

Doppler sonography of the direction of flow in the

main portal vein was performed using a scanner

(Sequoia 512, Acuson Solutions, Mountain View,

CA) with a 1.75- to 4-MHz sector transducer (4V1,

Acuson Solutions) or a 2.5- to 4-MHz sector trans-

ducer (4V2,

Acuson Solutions).

CT Interpretation

Two radiologists independently reviewed the

randomized CT images of all 36 patients on a

PACS (picture archiving and communication sys-

tem) workstation (Impax DS 3000 [release 4.1],

Agfa, Mortsel, Belgium). Observers were unaware

of clinical and sonographic findings. Both observ-ers recorded the following CT signs: short-axis di-

ameter of the main portal vein, which was

measured midway between the splenoportal con-

fluence and the portal vein bifurcation in the porta

hepatis; maximum short-axis diameter of the supe-

rior mesenteric vein, measured on the first image

that was clearly inferior to the splenoportal conflu-

ence; diameter of the splenic vein, measured adja-

cent to the midportion of the pancreatic tail;

presence or absence of ascites; presence or ab-

sence of varices; and spleen size, recorded as the

maximum axial diameter. In addition, for mul-

tiphase CT examinations (

n

= 20), the presence or

absence of early (i.e., arterial phase) enhancement

of the main portal vein was recorded.

Data Analysis

Statistical analysis was performed using statis-

tical analysis software (SAS version 8.1, SAS,

Cary, NC). Continuous data (vessel diameters and

spleen size) were examined by univariate analysis

using the two-tailed Cochran t

test.

Noncontinuous

data (all other categories) were examined using

Fisher’s exact test. The univariate analyses were

performed separately for the data for each ob-

server. All p values of 0.05 or less were considered

significant. Interobserver agreement for categori-

cal data was measured with kappa statistics [16].

Interobserver agreement for continuous data was

assessed using Bland-Altman regression [17] with

Bradley-Blackwood p

values [18]. Multivariate

analysis was performed using logistic regression

with a generalized linear model to account for thepresence of two observers. Parameters were se-

lected in a stepwise fashion with a type 3 signifi-

cance level of 0.05 or less required for factors to

remain in the model. Receiver operating character-

istic (ROC) analysis and area under the ROC curve

(A

z

) calculations were performed to evaluate pre-

dictive models.

Results

The CT signs recorded by each observer

showed high interobserver consistency for

all measurements other than the presence of

varices and the size of the spleen. A small

main portal vein correlated strongly (

p

<0.01) with hepatofugal flow by univariate

and multivariate analyses (Fig. 1). No other

signs achieved significance by either

method. ROC analysis using the diameter of

the main portal vein to predict hepatofugal

flow revealed an A

z

of 0.83 for observer 1

and 0.74 for observer 2 (Fig. 2).

Observer 1 found that the main portal vein

measured less than 1 cm in eight (44%) of 18

patients with hepatofugal flow, but in only

one (6%) of 18 patients with hepatopetal

flow (

p

< 0.02). Thus, the sensitivity of this

sign for predicting hepatofugal flow was

44% and the specificity was 94%. Observer 2found that the main portal vein measured less

than 1 cm in seven (39%) of 18 patients with

hepatofugal flow and 0 of 18 patients with

hepatopetal flow (

p

< 0.01), for a sensitivity

of 39% and a specificity of 100%.

The 1-cm measurement was the largest

(most sensitive) threshold that could be used

to predict hepatofugal flow without signifi-

cantly reducing specificity, given that both

observers measured the main portal vein at

or slightly above 1 cm in several patients

with hepatopetal flow (Fig. 1). A lower

threshold would reduce sensitivity without

significantly increasing specificity, and ahigher threshold would greatly reduce speci-

ficity with only mildly increasing sensitivity

(Fig. 2). A representative case illustrates the

finding of a small portal vein in a patient

with hepatofugal flow (Fig. 3). Arterial phase

enhancement of the portal vein was seen in

only one patient; in that patient, flow in the

portal vein was hepatopetal on sonography 1

day before CT (Fig. 4).



CT Signs of Hepatofugal Portal Venous Flow


1631

0

0

0.2

0.2

0.4

0.4

0.6

0.6

0.8

0.8

1

1

False-Positive Fraction

T r u e - P o s i t i v e F r a c t i o n

Observer 1 Observer 2

D i a m e t e r o f M a i n P o r t a l V

e i n ( c m )

Hepatopetal Hepatofugal Hepatopetal Hepatofugal0

0.5

1

1.5

2

2.5

Fig. 2.—Diagram shows receiver operating characteristic (ROC) values achieved usingsmall main portal vein diameter to predict hepatofugal flow in main portal vein in patients with cirrhosis. Operating points achieved by predicting hepatofugal flow whenmain portal vein diameter was less than 1 cm are shown for observer 1 (×) and observer2 (Δ). Note that at appropriate operating points, this sign is highly specific for hepatofu-gal flow. Area under ROC curve (Az ) was 0.83 for observer 1 and 0.74 for observer 2.

Fig. 1.—Diagram shows diameters of main portal vein in patients with hepatopetalflow versus hepatofugal flow. Note that main portal vein diameter of less than 1 cmis highly specific for hepatofugal flow.

Fig. 3.—73-year-old woman with cirrhosis due to alcohol abuse.A, Axial CT scan obtained during portal venous phase shows small (8 mm in diameter) main portal vein (arrow ); this finding strongly correlates with hepatofugal flow.B, Sonogram shows hepatofugal flow in main portal vein.

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1632


Bryce et al.

Discussion

Our finding that a relatively small main

portal vein in patients with cirrhosis indi-

cates hepatofugal flow is consistent with the

physiology of hepatofugal flow in the cir-

rhotic liver. The average size of the main

portal vein in healthy adults has been found

to be 1.0 cm [19]; a main portal vein of less

than 1 cm can be considered relatively small

in a cirrhotic patient because portal hyper-

tension tends to increase portal vein size

[20]. Normally, the portal vein receives flow

from the superior mesenteric vein and the

splenic vein. In patients with cirrhosis and

hepatofugal flow in the main portal vein, the

portal vein is supplied only by the hepatic

artery, which also supplies the hepatic veins.

This decrease in flow volume could explain

the decreased diameter of the portal vein. (A

small main portal vein in cirrhotic patients

has been associated with spontaneous sple-norenal shunts [21], a phenomenon that

would also be expected to reduce hepatic

portal venous perfusion.) Although specific

for hepatofugal flow, this sign was of only

moderate sensitivity in our study group.

Possible explanations for the limited sensi-

tivity may include a tendency for the vein to

remain patulous after enlarging in earlier

stages of portal hypertension and the possi-

bility that portal hypertension may provide a

continuing impetus for venous enlargement,

despite a reduction or reversal in flow.

Arterial phase enhancement of the portal

vein has been reported as a sign of hepatofu-

gal flow [1, 22]. In our study, this sign was

present in only one of 20 patients undergoing

CT with arterial phase contrast enhancement,

and Doppler sonography of this patient 1 day

before CT showed hepatopetal flow. The

finding of arterial phase enhancement of the

portal vein on CT in a patient with hepato-

petal portal venous flow on sonography is

puzzling but might be explained by transient

changes in flow direction in the portal

venous system. Such flow changes can occur

spontaneously in cirrhotic patients [23], in

the postprandial state [24, 25], and during

hepatic arteriography [26]. Disturbance of

baseline physiology during abdominal CT,

such as due to breath-hold technique or bolus

administration of IV contrast material, may

alter portal venous hemodynamics. For ex-

ample, contrast administration might elevate

right heart and hepatic vein pressures, and

the subsequent increased shunting of hepatic

arterial blood into the portal venous system

may result in temporary hepatofugal flow.

Our study has several limitations. The sam-

ple size was small and may have restricted the

power of the study to detect differences be-

tween the hepatopetal and hepatofugal

groups. For example, the prevalence of ascites

and varices was higher in patients with

hepatofugal flow, but these differences did not

achieve statistical significance. These factors

might exhibit an association with hepatofugal

flow in a larger study. CT and sonography

were not immediately contemporaneous. The

lag between the examinations may have low-

ered the sensitivity of the study for additional

predictors of hepatofugal flow, although the

possible effects of the time difference would

be expected to apply to both hepatopetal and

hepatofugal groups of patients. The lag be-

tween studies would not be expected to gener-

ate spurious associations and should not

detract from the finding that a small portal

vein size is associated with hepatofugal portal

venous flow. Analysis of additional sonogra-

phy examinations of the study population pro-

vided evidence that the direction of portal

venous flow in our subjects was stable. There-

fore, it is reasonable to expect that the direc-

tion of flow at the time of CT would be

accurately predicted by the contemporaneous

sonographic examination that was evaluated.

Fig. 4.—49-year-old man with cirrhosis due to chronic hepatitis C infection.A, CT scan obtained during arterial phase shows contrast enhancement of portal vein. This sign is thought to indicate hepatofugal portal venous flow.B, Doppler sonogram obtained 1 day earlier than A, however, reveals hepatopetal flow.

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CT Signs of Hepatofugal Portal Venous Flow


1633

High interobserver consistency was not

seen for the measurement of spleen size and

assessment for the presence or absence of va-

rices. The discrepancy in identification of va-

rices between observers could be explained by

a greater sensitivity of observer 2 for varices in

borderline cases, given that all cases identified

as positive by observer 1 were also called posi-

tive by observer 2, but not vice versa. The in-

terobserver variation regarding spleen size

may have resulted from the complex and

partly subjective methodology used, which in-

volved identifying the maximal single dimen-

sion of the spleen on any axial image.

This study did not seek to measure the

prevalence of hepatofugal flow in the entire

population of cirrhotic patients, although this

information would be required to determine

predictive values. This is important given that

our sign, although highly specific, is of lim-

ited sensitivity. The prevalence of hepatofu-

gal flow in unselected cirrhotic patients has

been previously estimated at 3.1–3.4% [2,

27], rising to 9% or more in patients with ad-

vanced cirrhosis [2, 28]. Finally, the diagno-

sis of cirrhosis was confirmed histologically

in only about one third of the study subjects.

However, most patients with a diagnosis of

cirrhosis do not undergo histologic confirma-

tion. Restricting the analysis to only those pa-

tients with a histologic diagnosis would have

selected for substantially more diseased or

symptomatic patients, possibly harming the

generalizability of our results. Given that all

patients in this study had significant risk fac-tors for cirrhosis, had imaging features con-

sistent with cirrhosis, and had either

histologic confirmation of cirrhosis or had

been assigned the diagnosis of cirrhosis at a

tertiary care center (by a gastroenterologist in

all but two cases), we believe that the proba-

bility of noncirrhotic patients existing within

the study population is low.

In conclusion, our data suggest that a main

portal vein diameter of less than 1 cm is

highly specific for hepatofugal portal venous

flow in cirrhotic patients, although the sensi-

tivity of this sign is limited. If validated in

prospective studies, this sign may be usefulwhen sonography is limited or may prompt

sonographic assessment in patients not

known to have hepatofugal flow.

References

1. Wachsberg RH, Bahramipour P, Sofocleous CT,

Barone A. Hepatofugal flow in the portal venous

system: pathophysiology, imaging findings, and di-

agnostic pitfalls. RadioGraphics

2002;22:123–1402. Tarantino L, Giorgio A, de Stefano G, et al. Re-

verse flow in intrahepatic portal vessels and liver

function impairment in cirrhosis. Eur J Ultra-

sound

1997;6:171–177

3. Smith-Laing G, Camilo ME, Dick R, Sherlock S.

Percutaneous transhepatic portography in the as-

sessment of portal hypertension: clinical correla-

tions and comparison of radiographic techniques.

Gastroenterology

1980;78:197–205

4. Wachsberg RH, Simmons MZ. Coronary vein di-

ameter and flow direction in patients with portal

hypertension: evaluation with duplex sonography

and correlation with variceal bleeding. AJR

1994;162:637–641

5. Komatsuda T, Ishida H, Konno K, et al. Color

Doppler findings of gastrointestinal varices. Ab-dom

Imaging

1998;23:45–50

6. Matsumoto A, Hamamoto N, Ohnishi A, et al.

Left gastric vein hemodynamics and variceal re-

currence in patients undergoing prophylactic en-

doscopic ligation of high-risk esophageal varices.

Gastrointest

Endosc

1999;50:768–774

7. Finucci G, Bellon S, Merkel C, et al. Evaluation

of splanchnic angiography as a prognostic index

of survival in patients with cirrhosis. Scand

J

Gastroenterol

1991;26:951–960

8. Oliver JH 3rd, Baron RL, Dodd GD 3rd, Peterson

MS, Carr BI. Does advanced cirrhosis with porto-

systemic shunting affect the value of CT arterial

portography in the evaluation of the liver? AJR

1995;164:333–337

9. Ralls PW. Color Doppler sonography of the he-patic artery and portal venous system. AJR

1990;155:517–525

10. Johansen K, Paun M. Duplex ultrasonography of the

portal vein. Surg Clin North Am 1990;70:181–190

11. Burkart DJ, Johnson CD, Morton MJ, Ehman RL.

Phase-contrast cine MR angiography in chronic

liver disease. Radiology

1993;187:407–412

12. Imazu H, Matsui T, Noguchi R, et al. Magnetic

resonance angiography for monitoring prophylac-

tic endoscopic treatment of high risk esophageal

varices. Endoscopy

2000;32:766–772

13. Finn JP, Kane RA, Edelman RR, et al. Imaging of

the portal venous system in patients with cirrho-

sis: MR angiography vs duplex Doppler sonogra-

phy. AJR

1993;161:989–994

14. Herlinger H. Arterioportography. Clin

Radiol

1978;29:255–275

15. Nelson RC, Lovett KE, Chezmar JL, et al. Com-

parison of pulsed Doppler sonography and an-

giography in patients with portal hypertension.

AJR

1987;149:77–81

16. Landis JR, Koch GG. The measurement of ob-

server agreement for categorical data. Biometrics

1977;33:159–174

17. Bland JM, Altman DG. Statistical methods for as-

sessing agreement between two methods of clini-

cal measurement. Lancet

1986;1:307–310

18. Bradley EL, Blackwood LG. Comparing paired

data: a simultaneous test of means and variances.

Am Stat 1989;43:234–235

19. Niederau C, Sonnenberg A, Muller JE, Erckenbre-

cht JF, Scholten T, Fritsch WP. Sonographic mea-

surements of the normal liver, spleen, pancreas, and

portal vein. Radiology

1983;149:537–540

20. Subramanyam BR, Balthar EJ, Raghavendra BN,

Lefleur RS. Sonographic evaluation of patients

with portal hypertension. Am J Gastroenterol

1983;78:369–373

21. Brancatelli G, Federle MP, Pealer K, Geller DA.

Portal venous thrombosis or sclerosis in liver

transplantation candidates: preoperative CT find-

ings and correlation with surgical procedure. Ra-

diology

2001;220:321–328

22. Park CM, Cha SH, Kim DH, et al. Hepatic arteri-

oportal shunts not directly related to hepatocellular

carcinoma: findings on CT during hepatic arteriog-

raphy, CT arterial portography and dual phase spi-

ral CT. Clin Radiol 2000;55:465–470

23. Hoevels J, Lunderquist A, Tylen U. Spontaneous

intermittent reversal of blood flow in intrahepatic

portal vein branches in cirrhosis of the liver. Car-

diovasc Radiol

1979;2:267–273

24. de Vries PJ, de Hooge P, Hoekstra JB, van Hat-

tum J. Postprandial reversal of the portal venous

flow in a patient with liver cirrhosis. Neth J Med

1995;47:235–240

25. Tochio H, Kudo M, Nishiuma S, Okabe Y. Intra-

hepatic spontaneous retrograde portal flow in pa-tients with cirrhosis of the liver: reversal by food

intake. AJR

2001;177:1109–1112

26. Ohnishi K, Saito M, Sato S, et al. Direction of

splenic venous flow assessed by pulsed Doppler

flowmetry in patients with a large splenorenal

shunt: relation to spontaneous hepatic encephalop-

athy. Gastroenterology

1985;89:180–185

27. Gaiani S, Bolondi L, Li Bassi S, Zironi G, Siringo

S, Barbara L. Prevalence of spontaneous hepatofu-

gal portal flow in liver cirrhosis: clinical and endo-

scopic correlation in 228 patients. Gastroenterology

1991;100:160–167

28. von Herbay A, Frieling T, Haussinger D. Color

Doppler sonographic evaluation of spontaneous

portosystemic shunts and inversion of portal

venous flow in patients with cirrhosis.

J Clin Ul-trasound

2000;28:332–333

ct signs of fugal portal venous flow in patients with cirrhosis

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