This document discusses non-invasive imaging techniques for evaluating portal hypertension. Ultrasound is the most widely used initial imaging modality to assess for portal vein patency, presence of collaterals, portal blood flow, and changes of cirrhosis. CT and MRI can further evaluate the portal venous system and collateral vessels. Ultrasound Doppler is used to measure portal blood flow direction, velocity, and assess for portosystemic collaterals and changes in hepatic veins. Imaging findings of various etiologies of portal hypertension are described, including cirrhosis, non-cirrhotic portal fibrosis, portal vein thrombosis, Budd-Chiari syndrome, and extrahepatic causes.

1. NON- INVASIVE IMAGING OF PORTAL
HYPERTENSION
DR. DEVKANT LAKHERA

2. Portal hypertension
Increase in portal pressure above 6-
10 mm Hg
Gradient - of more than 5 mm Hg
between hepatic veins and portal vein
Carries blood form GIT and spleen,
pancreas and gall bladder

3. PORTAL VEIN - Anatomy
Length - 6-8 cm
Caliber - 9-12 mm
Location:-
NECK OF PANCREAS
L1 –L2 vertebral level
Venules hepatic sinusoids
Terminal hepatic veins IVC heart
Hepatoduodenal ligament

4. Blood is not pumped  Driven via gradient
Pressure = Flow x Resistance
Gradient
Portal system
Caval venous
system
Valveless

5. Portocaval anastomosis
Distal esophagus
(Left gastric vein – oesophageal vein azygous  SVC)
Rectum
(Superior rectal– Middle and inferior rectal Internal
iliac)
Umbilicus
(Superficial epigastric  femoral  External iliac –
Paraumblical) (developed collaterals)
Tributary collaterals
Developed Collaterals (Hepatofugal)
gastrorenal// splenorenal// splenoretroperitoneal//
Paraumbilical vein: Runs in the falciform ligament and
connects the left portal vein to the systemic epigastric veins
near the umbilicus (close during development and reopen later

6. Pre-sinusoidal
(MC in India)
Sinusoidal Post-sinusoidal
Portal vein
thrombosis
Cirrhosis
(Hepatitis>
Alcoholic)
Budd-Chiari syndrome
Extrinsic
compression
of portal vein
Hepatic veno-occlusive
disease
Schistosomiasis Right heart failure
Causes of
cirrhosis
Hepatic
Intrahepatic

7. Non invasive imaging modalities
 Ultrasound and CDFI – Most widely used
Vascular patency
Presence of collaterals
Portal flow
Distinguish between extra and intrahepatic portal hypertension
Changes of cirrhosis
 Computed tomography and MRI – Portal venous system and collateral assessment.

8. INTRAHEPTIC PORTAL HYPERTENSION
USG evaluation of liver – Cirrhosis
-- Altered size
-- surface nodularity of with coarsened
echo texture
-- reduction in the number of visible portal
or hepatic veins
-- segmental hypertrophy/atrophy
◦ Transverse diameter segment IV - (<30 mm)
-- Splenomegaly and ascites.

9. Increased nodularity in liver undersurface enlargement of the caudate lobe

10. CT scan
Early - fatty infiltration (alcoholic liver disease)
Diminished volume
Nodularity of the liver, parenchymal
heterogeneity
Nonuniform lobar atrophy or hypertrophy may be
demonstrated
widening of the gallbladder fossa
enlargement of the lateral segment (LS) of the left lobe and
caudate lobe (C) of the liver, ascites, varices (red arrow), and
splenomegaly (S).

11. Prominent porta hepatis and intrahepatic
fissures - Hepatic atrophy
Regenerative nodules – Isoattenuating .
Very advanced cirrhosis with small nodular liver with
hypertrophy of the caudate lobe and extensive ascities

12. Hepatic C/RL ratio
line 1: Right lateral border of the portal vein
line 2: Left lateral border of the caudate lobe
line 3: Midway between the portal vein and the
IVC extended to the right liver edge
RL measurement: C measurement
caudate-right lobe ratio: C/RL
C/RL >0.65 = 96% likely to be cirrhotic//C/RL >0.73 = 99% likely
to be cirrhotic
: axial slice immediately below the bifurcation of the main
portal vein

13. Non cirrhotic portal fibrosis (Pre-sinusoidal portal hypertension
Smooth liver surface
Marked dilation of portal vein (selectively
left branch)
Thickening of portal vein wall
Increase in periportal echogenicity
increase in periportal echogenicity with normal parenchymal echotexture

14. CT
Normal sized liver
Splenomegaly
Dilated portal and splenic veins

15. 1. Portal vein diameter
2. Portal flow direction
3. Portal velocity and waveforms
4. Presence of portosystemic collaterals
5. Hepatic vein evaluation
6. Hepatic artery changes.
VASCULAR EVALUATION IN PORTAL HYPERTENSION

16. Portal vein diameter –> 9-12 mm in quiet respiration
>13 mm indicates portal hypertension
(>17mm –Large varices)
Portal vein diameter
(1-2 cm proximal to bifurcation)

17. Splenic vein and
Superior mesenteric vein
Splenic vein and superior mesenteric
vein - Diameter > 10mm
increase of diameter <20% during
inspiration
Loss of respiratory variation in these vessels is important sign

18. Normal portal vein
flow and velocity
Undulating hepatopetal flow.
Remain above baseline
Mean portal venous flow velocity
- 12 to 18 cm/sec
Average portal flow – 500-900
ml/min
Normal portal venous flow direction and waveform.

19. Normal portal vein flow
May become accentuated in portal hypertension

20. Portal hypertension
Portal vein loses its undulatory pattern and
becomes monophasic.
Later flow becomes biphasic and finally
hepatofugal
Flow velocity < 12cm /sec
US image shows slow flow in the main portal vein

21. Reversal of flow –Hepatofugal flow

22. Interpretation of flow
Normal flow To and Fro flow Reversed flow
Portal hypertension Advanced PHTN
Cardiac failure

23. Other causes of portal vein dilatation
Portal vein dilatation and flow reversal can CHF.
--- portal flow is markedly pulsatile
--- dilated IVC
Cardiac failure
Tricuspid regurgitation
Portal vein - Exaggerated pulsatality

24. Vascular indices
Liver Vascular Index
(LVI = PVVel/ Hepatic Artery PI) - < 12 cm/sec
Congestive index :
Cross-sectional area mean flow velocity of the portal trunk - > 0.13 cm/sec

25. Effective liver perfusion
Both the volume flow and velocity – decrease
may increase - large paraumbilical collateral
is lower as calculated from flow volume in portal trunk minus portal flow volume in the
umbilical vein.

26. Important indicators of portal hypertension.
Left gastric
Short gastric
Paraumblical
Splenorenal
Splenoretroperitoneal
Splenocaval
Splenoportal
Portosystemic Venous
Collaterals

27. Left gastric (coronary vein) – Normally <4mm  > 7mm
Associate with esophageal and gastric varices
Short gastric veins-- spleen and gastric wall.
Left gastric (coronary vein)

28. Paraumbilical vein

29. Paraumbilical vein
Ligamentum teres in the left lobe of liver
Recanalized visible as a channel greater
than 3 mm in diameter
Hepatofugal flow
Recanalization of umbilical vein is a highly
specific sign of portal hypertension

30. Splenorenal shunts --Splenic hilar
Splenoretroperitoneal
Spenocalval
Splenoportal

31. Hepatic vein assessment
Doppler spectral traces from normal
hepatic veins have a triphasic appearance
two waves that represent atrial and ventricular
diastole and a small wave that occurs in atrial systole
Altered hepatic vein waveforms
50% of patients with cirrhosis  flattening of the
phasic oscillations

32. Loss of pattern
Monophasic flow
Cirrhosis (Poor prognosis)
Infiltrative liver disease
Budd Chiari (Hepatic vein thrombosis)
Pulsed Doppler waveform analysis shows loss of the normal
triphasic hepatic vein pulsatility.

33. Exaggerated phasicity
Congestive heart failure
Tricuspid incompetence

34. Hepatic artery
normal hepatic artery (HA)
-- 4-6 mm
-- 25 to 30% of blood to the liver.
-- anterior to the portal vein
systolic velocity - 30 to 40 cm/sec and
diastolic velocity - 10-15 cm/sec
.

35. HEPATIC ARTERY
Resistivity Index -0.55 to 0.81
Pulsatility index (PI) - 1.16 to 1.24
Increased in chronic liver disease

36. CT
Splenoportal axis – Best visualized on portal phase
images
Retroperitoneal and mesenteric collaterals are better
visualized on CT
Axial CT scan showing esophageal (white arrow) and
paraesophageal (red arrow) varices. Superficial collateral
vessels are also present (yellow arrows

37. Coronal reformatted MDCT image shows short gastric and
perigastric varices (arrow).//Axial CECT in portal phase showing
recanalized paraumbilical vein.

38. Extrahepatic portal hypertension
Portal vein occlusion –Thrombosis, Tumor
invasion or compression.
Causes
◦ Sepsis.
◦ Acute Pancreatitis
◦ Tumor invasion – Pancreatic / HCC
◦ Hypercoagulable states
Non visualization of portal vein to thrombus occluding the of
PV (echogenic intraluminal material(arrow) or absent color flow

39. CT
Presents
Low attenuation filling defect
Lack of portal vein enhancement

40. Portal vein thrombosis
Contrast-enhanced fat-saturated T1-weighted
MRI in a 62-year-old woman with near-
occlusive thrombus in the main portal vein

41. Cavernous transformation
Tortuous vessels in the porta
hepatis
periportal collateral circulation

42. Cavernous transformation of liver

43. Splenic vein thrombosis
Regional portal hypertension
Pancreatitis and pancreatic carcinoma
short gastric and gastroepiploic veins return blood to the patient PV

44. Budd-Chiari Syndrome
Hepatic vein thrombosis
Rare
Acute : Result of thrombosis of main hepatic vein of IVC
Chronic: due to intrahepatic venous fibrosis

45. USG
No flow in hepatic vein or discontinuity between
the main hepatic vein and the inferior vena cava
Reversed flow in hepatic veins and intra-and
extrahepatic collaterals
increased resistive index within the hepatic
artery: >0.75

47. CT
Inhomogeneous mottled apperance (nutmeg
liver)
Delayed enhancement of the peripheral liver
with accompanying central low density areas
Inability to identify hepatic veins
Chronic phase, there is caudate lobe
enlargement and atrophy of the peripheral
liver in affected areas

48. THANK YOU

50. sample volume should be placed in the midportion of the lumen
An angle indicator line is subjectively placed parallel to the vessel
direction, velocity, and acceleration

51. Factors which affect imaging
Focal zone at the level of portal vein
Inc sensitivity
◦ Slow velocity range
◦ Small angle
◦ Patient positioning
◦ Small color box
Aliasing