Doppler ultrasound of the portal system - Normal findings
1. Doppler of the portal system
Normal findings
Samir Haffar M.D.
Assistant professor of gastroenterology
2. Doppler of normal portal system
• Normal US of portal system
• Normal Doppler US of portal system
Principles of Doppler US
Adjusting color Doppler US
Adjusting spectral Doppler US
Normal portal vein
Normal hepatic veins
Normal hepatic artery (impedance indices)
3. Sagittal & transverse planes of US
Sagittal plane Transverse plane
Abraham D et al. Emergency medicine sonography: Pocket guide.
Jones & Bartlett Publishers, Boston, MA, USA, 1st edition, 2010.
4. Normal portal venous circulation
Myers KA & Clough A. Making sense of vascular ultrasound. Arnold, London, 2004.
5. Normal hepatic circulation
The rule of three
• Superior mesenteric vein 2/3 – Splenic vein 1/3
• Right liver 2/3 – Left liver 1/3
• Portal vein 2/3 – Hepatic artery 1/3
6. Splenic vein
Transverse US view
Splenic vein behind tail, body & head of pancreas
Upper limit of normal: 10 mm
Gastroduodenal artery & CBD & in pancreatic head
Martínez-Noguera A et al. Abdom Imaging 2007 ; 32 : 136 – 149.
GDA
CBD
7. Inferior mesenteric vein
IMV inserting into portal system at confluence (33%)
Plane tangential to SV directed toward left upper quadrant
Plane tangential to IMV directed toward left lower quadrant
Wachsberg RH. Am J Roentgenol 2005 ; 184 : 481 – 486.
8. Wachsberg RH. Am J Roentgenol 2005 ; 184 : 481 – 486.
Anterior to LRV & SMA
Posterior to distal duodenum
Tangential to long axis of IMVTangential to long axis of SV
Anterior to SMA
Inferior mesenteric vein
Upper limit of normal: 7 mm
9. Jejunal vein
Wachsberg RH. Am J Roentgenol 2005 ; 184 : 481 – 486.
DUO
Anterior to duodenum & SMA before inserting into SMV
Should not be identified as IMV (behind distal duodenum)
Transverse sonogram
10. Respiratory variation of SV or SMV diameter
Forced inspiration & expiration
Berzigotti A & Piscaglia F. Ultraschall Med 2011 ; 32 : 548 – 571.
Splenic vein Superior mesenteric vein
Normal change ≥ 40% between forced inspiration & expiration
Normal SV or SMV < 10 mm
11. Left gastric vein / Coronary vein
Robinson KA et al. Ultrasound Quarterly 2009 ; 25 : 3 – 13.
Sagittal left paramedian US
of upper abdomen
Relationship of LGV to
SV, SMV, & PV
Upper limit of normal: 5 – 6 mm
12. Normal Left gastric vein anatomy
Coronary vein
Robinson KA et al. Ultrasound Quarterly 2009 ; 25 : 3 – 13.
Transverse US view
LGV seen anterior to bifurcation LGV arising from SV anterior to CA
Sagittal US view
13. Normal left gastric vein anatomy
Significant minority
Robinson KA et al. Ultrasound Quarterly 2009 ; 25 : 3 – 13.
Transverse view of upper abdomen
CV located posterior to origin
of hepatic artery
Sagittal view of upper abdomen
CV arising from superior aspect
of SV posterior to HA
14. Changing position of transducer for PV
IntercostalTransabdominal Subcostal
Kruskal JB et al. RadioGraphics 2004 ; 24 : 657 – 675.
15. Normal diameter of portal vein
Berzigotti A & Piscaglia F. Ultraschall Med 2011 ; 32 : 548 – 571.
Portal vein measured at crossing point with HA
Normal : < 13 or 16 mm
16. Normal branching pattern of portal vein
AbuRahma AF & Bergan JJ. Noninvasive vascular diagnosis: Practical guide to therapy.
Springer-Verlag, London , UK, 2nd edition, 2007.
H shape of left portal venous bifurcation
Right anterior & right posterior branches of right PV
2
3
45
8
6
7
17. Branches of right & left portal veins
H shape of left PV bifurcation
Right anterior & right posterior branches of right PV
Rumack CM, Wilson SR, & Charboneau JW. Diagnostic ultrasound.
Elsevier-Mosby, St. Louis, Missouri, USA, 3rd edition, 2005.
18. Umbilical vein remnant
Normal ≤ 3 mm
Robinson KA et al. Ultrasound Quarterly 2009 ; 25 : 3 – 13.
Transverse view of LL
Ligamentum teres
Hypoechoic remnant of UV
Communicates with LPV
Longitudinal view of LL
No detectable flow
within UV remnant
Color Doppler view
Ligamentum teres
Hypoechoic remnant of UV
19. Normal caudate lobe
Study of 66 healthy subjects
Bargalló X et al. Am J Roentgenol 2003 ; 181 : 1641 – 1645.
Sagittal epigastric line
Sagittal diameter: 45 ± 9 mm
Antero-posterior diameter: 24 ± 6 cm
Caudate lobe size Caudate lobe vein
Thin caudate vein
≤ 2 mm in all healthy subjects
20. Major anatomical variations of portal system
Gallego C et al. RadioGraphics 2002 ; 22 : 141–159.
Agenesis of right or left portal vein
Trifurcation at porta hepatis
Right anterior portal branch arising from left PV
Right posterior portal branch arising from main PV
Most frequent
21. Agenesis of left portal vein
Sato M et al. Eur Radiol 2000 ; 10 : 362 – 364.
Absence of horizontal portion of LPV
Aberrant vessel from anterior RPV to vertical portion of LPV
22. Anatomical variants of portal vein
Trifurcation of PV
Right anterior branch
arising from left PV
Right posterior branch
arising from main PV
Battaglia S et al. J Ultrasound 2010 ; 13 : 49 – 56.
23. Normal hepatic veins
Three hepatic veins enter IVC 2 cm caudad to right atrium
Middle & left hepatic veins form common trunk (60%)
Battaglia S et al. J Ultrasound 2010 ; 13 : 49 – 56.
24. Normal hepatic veins
Best seen on subcostal oblique view
Mansour MA et al. Vascular Diagnosis. Elsevier-Saunders, Philadelphia, 1st edition, 2005
Right, middle, & left HV seen as “bunny” on points to IVC
6/7
5/8
4
2
Hepatic veins divide liver into Couinaud system segments
25. Hepatic vein variants
Battaglia S et al. J Ultrasound 2010 ; 13 : 49 – 56.
2 left hepatic veins2 right hepatic veins 2 middle hepatic veins
2 right & 2 left hepatic veins Left accessory hepatic vein
26. Hepatic vein variants
Battaglia S et al. J Ultrasound 2010 ; 13 : 49 – 56.
Left accessory HV2 left hepatic veins2 middle hepatic veins
27. Short hepatic vein orifices
Desser TS et al. Am J Roentgenol 2003 ; 180 : 1583 – 1591.
Short hepatic veins from pericaval liver segments
Drain directly into IVC caudad to its junction with HV
28. Left-sided IVC
Myers KA & Clough A. Making sense of vascular ultrasound. Arnold, London, 2004.
Normal anatomy of IVC Anomalous left-sided IVC
Persistence of embryological AV
30. Normal hepatic artery
Measurement of HA at two cm distal to its origin from CT
Normal diameter: 5 ± 1 mm
Buscarini E et al. Ultraschall Med 2004 ; 25 : 348 – 55.
31. Hepatic artery
Abraham D et al. Emergency medicine sonography: Pocket guide.
Jones & Bartlett Publishers, Boston, MA, USA, 1st edition, 2010.
Hepatic artery between main portal vein & CBD
Longitudinal oblique view of porta hepatis
32. Anatomical variations of hepatic artery
* Michels NA. Am J Surg 1966 ; 112 : 337 – 47.
Myers KA & Clough A. Making sense of vascular ultrasound. Arnold, London, 2004.
10 anatomic variants of HA (dissection of 200 cadavers)*
• Right hepatic artery from SMA
• Common hepatic artery from SMA
• Common trunk for celiac axis & SMA
• Celiac trunk absent & its branches arise from aorta
33. Right hepatic artery from SMA
Battaglia S et al. J Ultrasound 2010 ; 13 : 49 – 56.
Common hepatic artery gives rise to GDA & LHA
Right hepatic artery replaced by branch of SMA
SMA
Branch of SMA
CHA
SMA
LHA
RHA
GDA
34. Common hepatic artery from SMA
Battaglia S et al. J Ultrasound 2010 ; 13 : 49 – 56.
Entire hepatic artery replaced by SMA
SMACHA
LHARHA
SMACHA
35. Left hepatic artery from left gastric artery
Battaglia S et al. J Ultrasound 2010 ; 13 : 49 – 56.
LHA originates from LGA
Runs alongside venous ligament
LGA
LHA
CHA
RHA LHA
LGA
36. Doppler of normal portal system
• Normal US of portal system
• Normal Doppler US of portal system
Principles of Doppler US
Adjusting color Doppler US
Adjusting spectral Doppler US
Normal portal vein
Normal hepatic veins
Normal hepatic artery (impedance indices)
37. Goals of Doppler
• Detection flow in a vessel
• Detection direction of flow
• Detection type of flow: Arterial or venous
Normal or abnormal
• Measurement of flow velocity
38. What is the Doppler phenomenon?
Doppler shift frequency (fd): ft – fr
Thrush A, Hartshorne T. Peripheral vascular ultrasound: How, why and when.
Elsevier Churchill Livingstone, London, 2nd edition, 2005.
ft
fr
39. Doppler equation
∆ F Doppler shift frequency (kHz)
F0 Ultrasound transmission frequency (MHz)
V Blood cell velocity (cm/sec)
Cos Ө Cos of angle between US & flow direction
C Speed of sound in soft tissue (1 540 m/sec)
∆ F = 2 F0 V Cos Ө / C
40. ∆ F
F0
V
Cos Ө
C
∆ F = 2 F0 V Cos Ө / C
1.6 kHz
5 MHz
60°
1 540 m/sec
Thrush A, Hartshorne T. Peripheral vascular ultrasound: How, why and when.
Elsevier Churchill Livingstone, London, 2nd edition, 2005.
Doppler equation
Converting Doppler shift frequency to velocity
?50 cm/s
41. Angle of insonation & Doppler effect
Kim MJ et al. Curr Probl Diagn Radiol 2009 ; 38 : 53 – 60.
Ө angle between transmitted beam & target vessel
Angles between 30° & 60° usually used for flow velocity
Angles exceeding 60° inadequate for flow velocity
42. Percentage error in velocity measurements
& angle of insonation
In order to minimize this error
Angles of insonation > 60° should not be used
43. Each examination should be performed with
Tahmasebpour HR et al. RadioGraphics 2005 ; 25 : 1561 – 1575.
• Gray-scale US
• Color Doppler
• Power Doppler
• Spectral Doppler
44. Sites of duplex insonation of portal system
Patnquin1 H et al. Am J Roentgenol 1987 ; 149 : 71 – 76.
45. Doppler of normal portal system
• Normal US of portal system
• Normal Doppler US of portal system
Principles of Doppler US
Adjusting color Doppler US
Adjusting spectral Doppler US
Normal portal vein
Normal hepatic veins
Normal hepatic artery (impedance indices)
46. Doppler panel on console of US imagers
Kruskal JB et al. RadioGraphics 2004 ; 24 : 657 – 675.
Each parameter can be adjusted to optimize color
or spectral Doppler components of examination
47. Color box size / Overlay
Kruskal JB et al. RadioGraphics 2004 ; 24 : 657 – 675.
Oversized color box
↑ frame rate & ↓ resolution
Reduced color box size
↓ frame rate & ↑ resolution
Color box should be as small & superficial as possible
48. Adjusting color velocity scale
Kruskal JB et al. RadioGraphics 2004 ; 24 : 657 – 675.
Color velocity scale 2 cm/sec
Color aliasing in PV & its branches
High color velocity scale 69 cm/sec
Apparent absence of flow in PV
Color velocity scale 30 cm/sec
Normal flow in a patent PV
49. Adjusting color gain
Kruskal JB et al. RadioGraphics 2004 ; 24 : 657 – 675.
Gain setting: 44%
Gain setting: 100%
Gain setting: 65%
50. Changing color baseline to avoid aliasing
Kruskal JB et al. RadioGraphics 2004 ; 24 : 657 – 675.
Color baseline too high
Flow within PV appears red
Accurate directional flow data
Color baseline lowered
Flow within PV appears green
Color equivalent of aliasing
51. Inversion of color flow
Kruskal JB et al. RadioGraphics 2004 ; 24 : 657 – 675.
Reversal of this inversion
Appropriate directional flow noted
Portal venous flow appears blue
Falsely suggests flow reversal
52. Changing color Doppler wall filter
Kruskal JB et al. RadioGraphics 2004 ; 24 : 657 – 675.
Highest wall filter setting
Color signal from low velocity
flow filtered out
Filling in of flow in hepatic veins
Low filter setting
53. Angle of insonation
Kruskal JB et al. RadioGraphics 2004 ; 24 : 657 – 675.
Transducer positioned perpendicular to flow
No color assigned, yielding false finding of absent flow
54. Doppler of normal portal system
• Normal US of portal system
• Normal Doppler US of portal system
Principles of Doppler US
Adjusting color Doppler US
Adjusting spectral Doppler US
Normal portal vein
Normal hepatic veins
Normal hepatic artery (impedance indices)
55. Obtain waveform at end of normal breath-out
• Take normal breath
• Take normal breath-out
• Stop breathing
• Then obtain a waveform
Deep inspiration should be avoided when possible
Robinson KA et al. Ultrasound Quarterly 2009 ; 25 : 3 – 13.
56. Anatomy of spectral Doppler
Angle correction
Cursor
Beam path
Sample volume
Baseline
EDV
Thrush A, Hartshorne T. Peripheral vascular ultrasound: How, why and when.
Elsevier Churchill Livingstone, London, 2nd edition, 2005.
PSV
Shade of gray related to strength of signal
received at that frequency
Time (s)
57. Optimizing gate size & position
Kruskal JB et al. RadioGraphics 2004 ; 24 : 657 – 675.
Sampling of flow in both portal vein & hepatic veins
Gate size too large
58. Adjusting spectral velocity scale
Spectral scale: 200 cm/sec Spectral scale: 50 cm/sec
Kruskal JB et al. RadioGraphics 2004 ; 24 : 657 – 675.
Color Doppler image, color bar, & color scale unchanged
Spectral component is active
59. Adjusting spectral Doppler gain
Gain setting 0% Gain setting 38%
Gain setting 77% Gain setting 100%
Kruskal JB et al. RadioGraphics 2004 ; 24 : 657 – 675.
60. Changing spectral baseline to avoid aliasing
Kruskal JB et al. RadioGraphics 2004 ; 24 : 657 – 675.
Aliasing of spectral waveform
Inaccurate waveform data
Spectral baseline lowered
Accurate quantitative data obtained
High spectral baseline
61. Changing wall filter
Kruskal JB et al. RadioGraphics 2004 ; 24 : 657 – 675.
High wall filter setting
Loss of low-velocity-flow of
waveform above baseline
Spectral waveform fills in toward
baseline as wall filter reduced
Sequential reduced wall filter
62. Inversion of spectral flow
Kruskal JB et al. RadioGraphics 2004 ; 24 : 657 – 675.
Appropriate color flow
Spectral waveform below baseline
Inversion of spectral waveform
Spectral waveform above baseline
64. Doppler of the normal portal system
• Normal US of portal system
• Normal Doppler US of portal system
Principles of Doppler US
Adjusting color Doppler US
Adjusting spectral Doppler US
Normal portal vein
Normal hepatic veins
Normal hepatic artery (impedance indices)
65. Normal pulsed Doppler of portal vein
Kruskal JB et al. RadioGraphics 2004 ; 24 : 657 – 675.
Sample gate placed in middle of main portal vein
Width of sample gate approximately half the lumen
Pulsed Doppler obtained at end of normal breath out
66. Measurement of portal vein velocity
Vmax
Vmin
Vmean
TAMV*
* TAMV: Time Average Mean Velocity
67. Variability of portal vein velocity
• Inter-observer variability
• Inter-machine variability (same equipment)
• Different states of fasting (at least 6 hours fasting)
• Differences in positioning (supine)
• Different exercise status (at least 10 min)
• Different phases of respiration (end of breath-out)
• Presence of collateral (especially re-canalized UV)
• Different cardiac output
Robinson KA et al. Ultrasound Quarterly 2009 ; 25 : 3 – 13.
Berzigotti A & Piscaglia F. Ultraschall in Med 2011 ; 32 : 548 – 571.
68. Normal portal vein
• Diameter Upper limits of normal: 13 – 16 mm
> 20 – 30% increase with food & inspiration
• Flow direction Towards liver (hepatopetal)
Throughout entire cardiac cycle
• Velocity Varies greatly (Max – Mean – Min – TAMV)
Mean velocity: 15 – 18 cm/s
Varies with cardiac & respiration activity
Undulating appearance of waveform
Goyal N et al. Clin Radiology 2009 ; 64 : 1056 – 1066.
69. Mean portal vein velocity in cirrhosis
Mean portal vein velocity (cm/sec)
Controls Cirrhosis
Gaiaini et al1 19 2.1 11.4 3.7
Moriyasu et al2 15.3 4 9.7 2.6
Zoli et al3 16 0.5 10.5 0.6
Ohnishi et al4 17 3.9 12 3
1 Gaiaini et al. Hepatology 1989 ; 9 : 815 – 819.
2 Moriyasu et al. Am J Roentgenol 1986 ; 146 : 735 – 739.
3 Zoli et al. J Ultrasoud Med 1985 ; 4 : 641 – 646.
4 Ohnishi et al. Gastroenterology 1985 ; 89 : 180 – 185.
15 cm/sec best cut-off value of mean PV velocity
70. Interpretation of portal vein flow
Normal flow
Kok Th et al. Scand J Gastroenterol 1999 ; 34 (Suppl 230) : 82 – 88.
Reversed flow
Advanced PHT
SOS
Porto-systemic shunt
TIPS
To and fro flow
Advanced PHT
Heart failure
Arterio-portal fistula
72. Normal cardiac pulsatility of portal vein
No pulsatility
VPI: 0
PVP: 1
Moderate pulsatility
VPI: 0.4
PVP: 0.6
Robinson KA et al. Ultrasound Quarterly 2009 ; 25 : 3 – 13.
73. Increased pulsatility of portal vein
Exaggerated pulsatility
Minimum velocity below baseline
Robinson KA et al. Ultrasound Quarterly 2009 ; 25 : 3 – 13.
- Portal hypertension
- Tricuspid regurgitation
- Right heart failure
- Arterio-portal vein fistula
74. Cross sectional area (cm²)
Mean flow velocity (cm/sec)
Congestion index of portal vein
Moriyasu F et al. Am J Roentgenol 1986 ; 146 : 735 – 739.
CI ≥ 0.08 Portal hypertension
Sensibility: 65-95% – Specificity: 100%
Normal Value 0.07 ± 0.03 cm.sec
Inter-observer variability in area measurements
Inter-observer variability in velocity measurements
Variability compounded when parameters combined in ratio
75. Portal vein flow volume
Q = Flow volume (ml/min)
Vm = Mean velocity of PV (cm/sec)
A = Area of portal vein (cm²)
Q = Vm x A x 60
Normal values: 825 ± 200 ml / min
15 ml / min / kg
76. Spleno-Portal Index (SPI)
Liu CH et al. Radiology 2008 ; 248 : 132 – 139.
Maximal images of spleen
Splenic index
Transverse d (cm) . Vertical d (cm)
Spleno-portal index: splenic index / mean PV velocity
Duplex US of portal vein
Mean PV velocity
77. ROC of spleno-portal index (SPI)
143 compensated cirrhosis (Child-Pugh: A)
Liu CH et al. Radiology 2008 ; 248 : 132 – 139.
SPI threshold of 3.0
Sen 92%, Sp 93%, PPV 91% & NPV 94% for esophageal varices
AUROC: 0.93
3.0
79. Helical portal vein flow
If not properly recognized
It can produce mistaken impression of PV flow reversal
Robinson KA et al. Ultrasound Quarterly 2009 ; 25 : 3 – 13.
Color Doppler US of PV Pulsed Doppler US of PV
80. Helical portal vein flow
Near the bifurcation
• Normal subjects 2%
• Severe chronic liver disease 20%
• Post-liver transplantation Donor PV > recipient PV
• Portal vein stenosis
• TIPS
Robinson KA et al. Ultrasound Quarterly 2009 ; 25 : 3 – 13.
81. Helical portal vein flow
Mimic of hepatofugal flow
Wachsberg RH et al. RadioGraphics 2002 ; 22 : 123 – 140.
Hepatopetal flow within liver confirms that net flow is hepatopetal
82. Doppler of the normal portal system
• Normal US of portal system
• Normal Doppler US of portal system
Principles of Doppler US
Adjusting color Doppler US
Adjusting spectral Doppler US
Normal portal vein
Normal hepatic veins
Normal hepatic artery (impedance indices)
83. Color Doppler of normal hepatic veins
Normal diameter: < 10 mm
2 cm before entrance into IVC
Atrial systole Ventricular systole
Buscarini E et al. Ultraschall Med 2004 ; 25 : 348 – 55.
84. Normal hepatic vein waveform – 3 components
Kruskal JB et al. RadioGraphics 2004 ; 24 : 657 – 675.
A Atrial systole
S Ventricular systole
D Atrial diastole
A
S D
S wave > D wave
Commonly described as triphasic
85. Normal hepatic vein waveform – 4 components
A Atrial systole
S Ventricular systole
V Atrial overfilling transitional wave
Below, at, or above baseline
D Atrial diastole
Kruskal JB et al. RadioGraphics 2004 ; 24 : 657 – 675.
86. Normal hepatic vein waveform – 5 components
A Atrial systole
C Small spike following A wave
S Ventricular systole
V Atrial overfilling transitional wave
D Atrial diastole
Scheinfeld MH et al. RadioGraphics 2009 ; 29 : 2081 – 2098.
87. Relationship of EKC, CVP & HV waveform
Desser TS et al. Am J Roentgenol 2003 ; 180 : 1583 – 1591.
88. Classification of Doppler HV waveform
Measurement taken in RHV or MHV
Zhang L et al. BMC Gastroenterology 2011 ; 11: 84 – 90.
Triphasic waveform
Biphasic waveform
Monophasic waveform
90. Damping index of HV waveform
Severe portal hypertension : HVPG > 12 mmHg
Kim MY et al. Liver International 2007 ; 27 : 1103 – 1110.
Minimum velocity of downward HV
Maximum velocity of downward HV
Damping index =
Normal value: < 0.6
Severe portal hypertension: ≥ 0.6
91. Damping index of HV waveform in cirrhosis
DI: 0.26
HVPG: 7 mmHg
DI: 0.72
HVPG: 15 mmHg
Kim MY et al. Liver International 2007 ; 27 : 1103 – 1110.
92. ROC of damping index in hepatic vein
Damping index ≥ 0.6 severe PHT
Sensitivity 76% – Specificity 82 % – AUC 0.86
Severe portal hypertension : HVPG > 12 mmHg
Kim MY et al. Liver International 2007 ; 27 : 1103 – 1110.
DI:0.6
93. Evaluation of HV spectral waveforms
Direction of flow BCS
No flow
Reversed flow
Arrhythmia
Patient or technical factors
Irregular
Fatty infiltration
Cirrhosis
Metastatic infiltration
BCS or SOS
↑ abd pressure (Valsalva)
Monophasic
Right heart failure
Tricuspid regurgitation
Yes
Regularity of flow
Antegrade
Mono- bi- or triphasic
Regular
D wave > S wave
Bi- or triphasic
Normal
No
Scheinfeld MH et al. RadioGraphics 2009 ; 29 : 2081 – 2098.
94. Doppler of normal portal system
• Normal US of portal system
• Normal Doppler US of portal system
Principles of Doppler US
Adjusting color Doppler US
Adjusting spectral Doppler US
Normal portal vein
Normal hepatic veins
Normal hepatic artery (impedance indices)
95. Impedance indices
Resistance index (RI) or Pourcelot’s index
RI: S – ED / S
Normal: 0.65 ± 10
Buscarini E et al. Ultraschall Med 2004 ; 25 : 348 – 55.
97. Normal hepatic artery
Low resistance flow
Diameter* 5 ± 1 mm
PSV 70 ± 10 cm/sec
RI 0.65 ± 10
PI 0.92 ± 0.1
* Buscarini E et al. Ultraschall Med 2004 ; 25 : 348 – 55.
Measurement of HA at 2 cm distal to its origin from CT
98. Interpretation of hepatic artery flow
ESLD: End Stage Liver Disease
Kok Th et al. Scand J Gastroenterol 1999 ; 34 (Suppl 230) : 82 – 88.
Decreased diastolic flow
ESLD
Reversed diastolic flow
ESLD
Low resistance flow
Normal
IMV originates anterior to the sacrum as the superior rectal (hemorrhoidal) vein & receives branches from the sigmoid and descendingcolon as it ascends to the left of midline adjacent to the inferior mesenteric artery and left gonadal vein.In the upper abdomen, the IMV passes posterior to the distal duodenum, anterior to the left renal vein, and then anterior to the superior mesenteric artery before anastomosing with the portal venous system.In a large autopsy series, the IMV inserted into the distal splenic vein in 38.0%, the portal confluence in 32.7%, and the superiormesenteric vein in 29.3% of cases. On CT, the diameter of the normal IMV rarely exceeds 6 mm.
Normal size of lobuscaudatus was defined as 6.8 ± 1.3 cm for the sagittal diameter.Hogrefe B. Sonographische Morphometrie der gesunden Leber. Personal communications.In: Boozari B et al. J Hepatol 2008 ; 49 : 572 – 580.
Major anatomical variations of the portal vein are uncommon but include1- agenesis of the right or left portal vein2- trifurcation at the portahepatis3- right anterior portal branch arising from the left portal vein4- Right posterior portal branch arising from the main portal vein
PV divides into right anterior, right posterior, & left portal veins at the same level.
Bunny: أرنب
Anomalous left-sided IVC from persistence of the embryological azygos vein.
Ө (theta), also referred to as the Doppler angle,is the angle between the transmitted beam and the direction ofblood flow within the blood vessel (the reflector path). Converting Doppler shift frequencies to velocity measurements.
Ө (theta), also referred to as the Doppler angle,is the angle between the transmitted beam and the direction ofblood flow within the blood vessel (the reflector path). Converting Doppler shift frequencies to velocity measurements.
The larger the angle of insonation, the greater the potential source of error in velocity measurement.
The frame rate is the rate per second at which complete images are produced.With pulse-echo imaging alone, the frame rate can exceed 50 images per second.However, the time required to produce color flow images is much longer, which significantly lowers the frame rate. The frame rate in color imaging is dependent on several factors.For example, the size and position of the color box have a great effect on the frame rate. The width of the box is especially important: The wider the box, the more scan lines are required and the longer it will taketo acquire the data to produce the image.
normal-appearing wall-to-wall flow in the main portal vein.
Too large: signal from adjacent vessel or extraneous parenchymaToo small: false impression of reduced or even absent flow
Food ingestion induces hemodynamic changes.Exercise and posture changes also induce hemodynamic changes.patients in follow-up should preferably be examined by the same operator and with the same equipment whenever possible.
Undulating: Variation of PV diameter with inspiration:Lack of caliber variation of the splenic and mesenteric vein during respiration is another parameter that has been investigated. In 1 study, this approach had a sensitivity of 80% and specificity of 100% in diagnosing portal hypertension. However, it is a method that has not gained widespread use, likely because of difficulties in measurement accuracy and interobserver variability.PV velocity:Significantly lower mean portal venous velocity was noted in cirrhotic patients (13 ± 3.2 cm/s versus 19.6 ± 2.6 cm/s in controls) by Zironi et al & 15 cm/s was considered as best cut-off value in detection of PHT, showing sensitivity & specificity of 88% and 96%, respectively.51. Zironi G, Gaiani S, Fenyves D, et al. Value of measurement of mean portal flow velocity by Doppler flowmetry in the diagnosis of portal hypertension. J Hepatol 1992;16:298-303.
VPI: venous equivalent to the arterial resistive index.In most normal subjects, Vmin less than half Vmax.
Cross-sectional area was calculated from the formula for the cross-section of an ellipse. Congestion index is a better marker for the diagnosis of PHT as it takes into account the velocity as well as diameter of PV.
Triphasic waveform due to transmitted cardiac activity & Similar to waveform for the jugular vein.Two negative waves and another positive wave.
Measurements taken in RHV & MHVAvoid artefact from transmitted cardiac movement in LHV
Acceleration resulting from focal compression by regenerative nodulesValue of 0.6 of DI showed a sensitivity of 75.9% and a specificity of 81.8% for the presence of severe portal hypertension (hepatic venous pressure gradient >12mmHg) (AUC = 0.860).
Low-resistance profile: - Broad systolic peak - Gradual deceleration from systole to diastole - Well-maintained diastolic flow throughout the cardiac cycle.
