development of various collateral pathways during portal hypertension : USG and CT

1. Portal hypertension and Porto-
systemic collateral pathways : Color
doppler and CT Portography
Presented by Dr. Anil kumar jangir

2. Ø Normal Portal circulation and
pathophysiology of Portal hypertension
Ø Color doppler evaluation of PHTN and
Varices
Ø CT Portography for evaluation of various
collateral pathways develops during portal
hypertension

3. NORMAL PORTAL CIRCULATION
• The portal circulation drains the digestive organs (from the
lower esophagus to the upper anal canal), the spleen and the
pancreas, and delivers the blood to the liver via the hepatic
portal vein
• The major tributaries of the portal vein are –
• Splenic V & SMV
• Other tributaries includes-
• IMV
• LGV
• RGV
• Pancreaticoduodenal vein
• Cystic vein

4. • PORTAL HYPERTENSION: PATHOPHYSIOLOGY
Ø In hepatocellular disease, the sinusoids are damaged, destroyed
or replaced. As the volume of normally functioning liver
parenchyma decreases, the resistance to portal venous Alow
increases, the portal vein dilates, and portal Nlow decreases and
with increasing severity, reverses i.e. turn hepatofugal .
• Resistance to portal inNlow occur either at the level of the portal
vein, hepatic sinusoids or hepatovenous outNlow
Ø In addition to an increase in hepatic vascular resistance to portal
blood Nlow, there is progressive splanchnic vasodilatation that
aggravates the portal hypertension syndrome by augmenting
portal blood Nlow.
Ø Recent updates in pathophysiologic understanding of portal
hypertension have also highlighted the contribution of hepatic
sinusoidal endothelial dysfunction elevating portal pressure.

5. • Hepatofugal Nlow within the
portal venous system is
associated with resultant
dilatation of the spleno-portal
axis and congestion of
tributaries which normally drain
into the spleno- portal axis
Normal portal venous pressure is between 5 to 10 mmHg, while the normal
pressure gradient between the portal vein and the inferior vena cava, known as
the hepatovenous pressure gradient (HVPG), is typically 1 to 5 mmHg
An elevation of pressure in the portal system above 6 mmHg is considered
portal hypertension. Above 12 mmHg pressure, portal hypertension becomes
clinically evident
Use of the ‘congestive index’ has been recommended to help diagnose portal
hypertension. This index is the ratio of the portal vein cross-sectional area
(cm2) divided by the mean portal Nlow velocity (cm/s).
In normal subjects, this ratio is less than 0.7.

6. • CAUSES OF PORTAL HYPERTENSION :

7. • CLINICAL SIGNIFICANCE
• (i) Diagnostic signiAicance: portosystemic collateral pathways
constitutes the direct sign of portal hypertension on imaging.
• (ii) Prognostic signiAicance: The more severe and more
prolonged the portal hypertension, the higher are the number
of portosystemic pathways.
• (iii) Therapeutic signiAicance: Detailed information about
collateral pathways is especially relevant when therapeutic
interventional procedures or surgery is being contemplated as
inadvertent collateral vessel injury can be potentially lethal As
these vessels can easily torn and are difNicult to repair
• There have been many reported cases of intraoperative
mortality and morbidity due to unintentional disruption of
unexpected portosystemic collaterals.

8. • Ultrasound evaluation of Portal Hypertension
ü Portal vein diameter (>13mm- Non speciNic)
ü Portal vein Nlow direction- Biphasic/Reverse Nlow
ü Portal velocity and waveform
ü Presence of Porto-systemic collaterals
ü Splenomegaly
ü Ascities
ü Hepatic vein evaluation- loss of triphasic
waveform(monophasic Nlow in cirrhosis)
ü Hepatic artery changes - Raised RI & PI in CLD

12. • The portal vein Doppler Nlow proNile in a fasting patient has a
relatively constant velocity of approximately 18 cm/s (`+/- 5
cm/s) towards the liver (hepatopetal)

13. • Spectral Doppler tracing of normal portal vein and hepatic
artery Nlow. Slight phasicity may be seen on the portal spectral
tracing due to respiration and a mild degree of periodicity may
be present, due either to retrograde pulsation transmitted from
the right heart via the hepatic vein or to the hepatic artery
systolic pressure wave. The dip in antegrade velocity coincides
with hepa4c arterial systole. The comparison of the two flow
profiles is achieved by interroga4ng with a wide sample volume
that encompasses both the artery and the vein in one tracing.

14. • As liver disease worsens, the periodicity in the portal vein may
become more pronounced, usually coinciding with hepatic
arterial systole.

15. • Finally, with end-stage liver disease, continuous hepatofugal
Nlow is observed, usually with increased periodicity.

16. Note: Pronounced periodicity may be seen in the portal vein,
which does not coincide with hepatic arterial systole.
This is usually due to cardiac disease, such as right ventricular
dysfunction or tricuspid regurgitation.

17. • Varices
• As portal hypertension progresses and pressure rises to 15 or
20 mmHg, sufNicient pressure exists to cause the development
of varices. These collateral pathways shunt blood from the
portal to the systemic circulation
• The magnitude and extent of collateral channels often depend
on the severity of portal hypertension i.e. the pressure gradient
driving the Nlow between the portal and the systemic
circulations and the duration of portal hypertension. The more
severe and more prolonged the portal hypertension, the higher
are the number of portosystemic pathways

18. • ORDER OF APPEARANCE OF COLLATERALS
• Backpressure transmitted through the tributaries of the portal
vein results in the engorgement of the collaterals outside the
gut wall. The varices outside the wall are called para-in location.
In turn, this is followed by dilatation of veins on the surface of
the visceral (muscular) wall in a peri-esophageal, peri-gastric or
perirectal location.
• Presence of perforating veins allows the transmission of this
backpressure to the deep intrinsic veins, which lie in
submucosa, and result in the formation of varices in a
submucosal or subepithelial location. These submucous veins
are, thus, the Nirst sites of 'bloodlogging' and become varicose
before those upon the outer surface of esophagus in portal
hypertension.

20. COLLATERAL PATHWAYS
• Common porto-systemic collaterals in cirrhosis include
gastroesophageal, paraesophageal, and perigastric varices,
gastro- or spleno-renal shunt, or recanalized paraumbilical vein
and abdominal wall collaterals

21. Short gastric varices :
Short gastric varices coursing
between the spleen and the greater
curvature of the stomach are best
imaged via the left Nlank, using the
enlarged spleen as a window
A tangled web of veins is seen
coursing cephalad from the splenic
vascular pedicle and extends
towards the diaphragm coursing
from the splenic vein, along the
greater curvature of the stomach
and from there to the systemic
circulation via oesophageal varices

22. Left gastric/coronary
varices :
Normally <4mm---> 7mm
Left gastric or coronary vein
varices course from the splenic
or portal veins along the lesser
curvature of the stomach and are
best imaged through the left lobe
of the liver
The left gastric varix is typically a
single large tortuous vessel
whereas short gastric varices
tend to be a plexus of small
vessels,
A large tortuous left gastric varix
is seen coursing from the region
of the coeliac axis towards the
gastro-oesophageal junction.

23. Recanalised paraumblical vein :
• Ligamentum teres in the left lobe of liver
• Recanalized visible as a channel greater than 3 mm in diameter
• Hepatofugal Nlow
• Recanalization of umbilical vein is a highly speciNic sign of portal
hypertension
• From the umbilicus, the blood may pass to the superior or
inferior epigastric veins, or through subcutaneous veins in the
anterior abdominal wall, known as the ‘Caput Medusa’, to reach
the systemic circulation.
• Patients with known portal hypertension, who present with an
umbilical hernia, should undergo imaging evaluation prior to
surgery as the hernia may contain a dilated varix, rather than
bowel. This pathway has less risk of life-threatening variceal
bleeding

24. Large vein carries Nlow from the left portal vein towards the transducer. It courses
along the falciform ligament and then turns caudad along the abdominal wall
passing towards the umbilicus, deep to the rectus muscles

25. ROLE OF MDCT-PORTOVENOGRAPHY
• MDCT plays a crucial role in providing insights into the
anatomy and physiopathology of the portal venous
system.
• As MDCT provides volumetric data, which can be
presented not only as axial sections but also as
multiplanar reformats, it provides outstanding images
for the visualization of these portosystemic collaterals.
• Delineation of these collaterals is especially important
before any therapeutic intervention or surgery so as to
avoid inadvertent injury.
• In addition, it allows concomitant assessment of liver
parenchymal changes, presence of splenomegaly, and
ascites.
• MIP and 3D reformatted images augment visualization
of the course and anatomic relationships of these
tortuous collateral channels.

26. Scanning technique-
Ø No oral contrast
Ø Arms raised above the head
Ø 125 ml contrast, Nlow rate- 4-5ml/sec
Ø Arterial phase scan (dome to bottom of liver)
Ø Portal phase scan (diaphragm to iliac crest)
Ø MIP, 3D reconstruction

27. CLASSIFICATION OF COLLATERAL PATHWAYS
I. COMMON COLLATERAL PATHWAYS
• Paraesophageal & (peri)esophageal
• Paragastric and (peri)gastric
• Pararectal and (peri)rectal
• Recanalized paraumbilical vein
& abdominal wall collaterals
• Splenorenal & gastro-spleno-renal
• Retroperitoneal collaterals

28. II. ECTOPIC VARICES
• Mesenteric and omental varices
• Para duodenal varices
• Jejunal or ileal varices
• Colonic varices
• Gallbladder and biliary varices
• Utero-vaginal & adnexal varices
• Vesical varices
• Anastomotic site and stomal varices

29. III. ATYPICAL (UNCOMMON) COLLATERAL PATHWAYS
• Mesenterico-gonadal or mesenterico-caval collaterals
• Intrahepatic porto-systemic shunt
• Transhepatic (extrahepatic) porto-systemic shunt
• Right posterior portal branch - IVC collaterals
• Right and left infradiaphragmatic shunts
• Vertebrolumbar-azygos Pathway
• Paraumbilical - left femoral collaterals
• Aberrant left gastric vein to left portal vein collaterals

30. • ESOPHAGEAL & PARA-ESOPHAGEAL COLLATERALS
• Typical CT appearance is nodular thickening of the esophageal wall
and enhancing nodular intraluminal protrusions with scalloped
borders
• Esophageal varices are enlarged, tortuous veins situated in the wall of
the lower esophagus formed by dilated subepithebial, submucosal
and perforating veins. While, the paraesophageal varices are situated
outside the esophagus in the posterior mediastinum
• Esophageal varices are usually supplied by the anterior branch of the
left gastric vein, whereas the posterior branch of this vein supplies
paraesophageal collateral vessels.
• Blood from the esophageal and paraesophageal varices usually drains
into the azygos vein (78%). Uncommonly, it drains into the IVC
(12%), or pulmonary or brachiocephalic veins
• Clinical signiAicance: Esophageal varices are common collateral
pathways observed in portal hypertension which may increase up to
six-fold in size and can carry up to a half litre of blood per minute.
Unfortunately, they are the commonest to bleed in cirrhotic patients
owing to the high-volume of blood Nlow and account for the high
mortality associated with spontaneous variceal bleeding.

31. Fig.- Axial CT image portovenous phase : Multiple large tubular and
serpiginous esophageal and paraesophageal varices at the level of the
esophageal hiatus of the diaphragm

32. Figure : Axial (A) and coronal (B) CECT images show large paraesophageal varices

33. esophageal varices appear as enhancing linear intramural protrusions within a
thickened esophagus paraesophageal collaterals seen as tuft of serpiginous
vessels in the posterior mediastinum located outside the walls of the esophagus

34. CT images show a tuft of posterior mediastinal paraesophageal collaterals deriving
their afferent supply from the coronary vein. The efferent drainage of esophageal and
paraesophagel collaterals occurs mainly through the azygous and hemiazygous venous
system

35. • GASTRIC & PERIGASTRIC COLLATERALS
• The left gastric, short gastric and posterior gastric veins can
signiNicantly enlarge in patients with portal hypertension and
contribute in the formation of gastric and perigastric varices
• The left gastric vein mainly contributes to formation of cardiac
varices whereas the short gastric vein and posterior gastric vein
contribute to formation of fundal varices.

36. • Gastric varices drain into the systemic veins primarily via the
esophageal- paraesophageal varices into the azygous-
hemiazygous veins. They may also drain into left renal vein by
way of gastrorenal shunt

37. • Clinical signiAicance: Although, gastric varices bleed less
frequently than esophageal varices the bleeding from them is
more severe and can be fatal because of the large size and rapid
blood Nlow of the varices.

38. • RECTAL & PERIRECTAL VARICES:
• Rectal varices manifested as discrete dilated submucosal veins
and constitute a pathway for portal venous Nlow between the
superior rectal veins (of the inferior mesenteric system) and the
middle and inferior rectal veins (of the iliac system).
• Afferent pathway: Inferior mesenteric vein (IMV) continues as
the superior rectal vein and acts as afferent to rectal varices.
The blood from superior rectal vein goes to extrinsic rectal
venous plexus (ERVP), which lies outside rectum below the
level of peritoneal reNlection. From the ERVP the blood Nlows by
perforators into the intrinsic rectal venous plexus (IRVP).
• Efferent pathway: From both ERVP and IRVP the portal
hemorrhoidal blood Nlows into systemic circulation through two
portosystemic shunts (recto genital and inter-rectal) which
eventually drain into the middle and inferior rectal veins. These
veins empty into the internal iliac veins.

39. Enlarged IMV continuing with dilated SRV and supplying rectal and perirectal varices.
Submucosal rectal varices (within the rectal wall) as well as perirectal varices (outside
the rectal wall) are well visualized

40. • RECANALIZED PARAUMBILICAL VEIN, UMBILICAL &
ABDOMINAL WALL COLLATERALS:
• The paraumbilical vein is a relatively common venous collateral
pathway in patients with cirrhosis.
• The paraumbilical vein originates from the umbilical portion of
the left portal vein courses along the falciform ligament,
frequently extending toward the umbilicus.

41. • Typically the recanalized paraumbilical vein courses caudally
towards the umbilicus along the anterior abdominal wall and
terminates into the systemic circulation via the inferior
epigastric vein.
• Alternately a cephalic course of the paraumbilical vein
communicates via the substernal or internal mammary veins
with the intercostal and azygous veins.

42. • The portosystemic collateralisation between the
paraumbilical vein, the periumbilical veins of the anterior
abdominal wall and the superNicial and deep epigastric veins
comprises of, what is known as, Cruveilhier- Baumgarten
syndrome.

43. SPLENO-RENAL & GASTRO-SPLENORENAL
COLLATERALS:
• Collaterals along the spleen, primarily supplied by the short
gastric vein, usually shunt the blood into the left renal vein
(systemic circulation) via a spleno-renal shunt
• The splenic collaterals may also drain into left suprarenal vein
and then into the left renal vein (i.e. splenoadrenorenal
shunt).
• Varices in this location may communicate with gastric,
perigastric or retrogastric varices and drain through a common
shunt into the left renal vein (spleno-gastrorenal shunt)
• Among patients with large spontaneous shunts, there is a high
frequency of hepatic encephabopathy and their closure has
shown good results in improving the patient's neurological
status.

45. Retrogastric and perigastric varices (that usually drain into the esophageal veins) can
occasionally drain in combination with the splenic varices into the left renal vein via a
spleno-gastrorenal shunt

46. • RETROPERITONEAL COLLATERALS:
• Arise from the colic or mesenteric branches and can occur
anywhere in the retroperitoneum (peripancreatic, perisplenic,
perirenal, paravertebral and retrocaval area).

47. ECTOPIC VARICES
• Almost any vein in the abdomen may serve as a potential
collateral channel to the systemic circulation.
• Ectopic varices are deNined as portosystemic collaterals
occurring anywhere in the gastrointestinal tract (or abdomen)
other than the esophagus and stomach.
• Such ectopic varices are located predominantly in the omentum,
mesentery, duodenum, jejunum, ileum, colon, rectum, pancreas,
gallbladder, and bile duct.
• Ectopic collaterals have also been reported in the uterus, vagina,
diaphragm and urinary bladder and at enterostomy stoma and
anastomotic sites.

48. • Gallbladder varices: They are present in approx. 12% of
patients with portal hypertension but are more frequent in
those with extrahepatic portal hypertension (30%). The
afferent veins are the cystic vein or a branch of the right portal
vein, while the efferent drain into the hepatic vein, intrahepatic
portal vein, or into systemic anterior abdominal wall collaterals
• Biliary varices: are primarily associated with extrahepatic
obstruction of the portal vein (EHPVO).
• Clinical signiAicance: These collaterals may cause extrinsic
compression and protrusion into the thin and pliable common
bile duct with or without upstream biliary dilatation (portal
biliopathy).

50. Pancreatic varices: are exceptionally rare. When present they are almost always
associated with portal vein thrombosis with concomitant thrombosis of the splenic
and the superior mesenteric veins

51. • ATYPICAL COLLATERAL PATHWAYS
• MESENTERICO-GONADAL & MESENTERICO-CAVAL VARICES:
• Mesenterico-gonadal or mesenterico-caval varices are
uncommon collateral pathways communicating between
intestinal or retroperitoneal tributaries of the superior and
inferior mesenteric veins and systemic veins
• The mesenteric varices are more commonly supplied by
branches SMV and usually drain into the IVC through the dilated
right gonadal vein, right renal vein, or sometimes directly join
the IVC.
• In rare instances IMV provides a conduit for portosystemic
shunting.

52. CT portography (coronal MIP images) shows the dilated ileocolic branch of the
superior mesenteric vein with saccular varices, draining into the markedly enlarged
right gonadal vein

53. INTRAHEPATIC PORTOSYSTEMIC VENOUS SHUNT:
• Atypical porto-systemic shunt.
• In the patient with an intrahepatic portosystemic venous shunt,
the portal vein communicates with the hepatic vein in or on the
surface of the liver through a dilated venous aneurysm.
• CT portography depicts the dilated portal branch running into
the venous aneurysm and early venous draining of the hepatic
vein

54. Intrahepatic portosystemic venous shunt : Axial contrast-enhanced (MIP) images reveal
a saccular venous aneurysm acting as a conduit between the right portal vein and the
right hepatic vein.
Clinical signiAicance: The shunt may mimic a hemangioma or aneurysm in the liver on
conventional CECT. More importantly, this collateral pathway can preclude crucial
procedures such as transjugular intrahepatic porto-systemic shunt (TIPSS).

55. • TRANSHEPATIC (EXTRAHEPATIC) PORTOSYSTEMIC VENOUS
SHUNT
• In this type of portosystemic shunt, the intrahepa4c portal vein
runs toward the outside of the liver and communicates with the
systemic veins.
• Paraumbilical venous collaterals running anteroinferiorly through
the falciform ligament are the best known of the various
transhepa4c portosystemic shunts.

56. Coronal MIP portography images
the intrahepatic peripheral branch of the left
lateral portal vein. It runs extrahepatically to drain
into the systemic circulation via the left intercostal
veins.

57. • References
1. Myron A Pozniak, Paul L Allan MD . Clinical doppler
ultrasound. 3rd edition
2. A. Arora, A. Mukund at al : CT-Portography depiction of
different Hepatofugal Collaterals in Cirrhosis. ECR 2013;
C-1135
3. Murad, Anirudh, Edward : Portal Hypertension-
Imaging of portosystemic collateral pathway and
assosiated image guided therapy. WJG Vol. 23(10)
2017mar

58. THANK YOU