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Ultrasound for Liver Screening:
Rationale and Protocol
Mindy M. Horrow, MD, FACR, FAIUM, FSRUVice Chair of Radiology
Einstein Medical Center
Professor of Radiology Sidney Kimmel Medical School
Philadelphia, PA
May 15, 2019
No Relevant Personal
Disclosures
Jay C. Horrow (spouse) is an employee of Merck & Co.
Outline
Goals: Screening and Surveillance ultrasound to detect
(1) Parenchymal disease: steatosis, fibrosis, cirrhosis
(2) Hepatocellular carcinoma (HCC)- focal or infiltrative
US every 6 months
Requires standardized, meticulous detail(1) Ease of comparison (2) Decrease inter-observer variability
Different approach from scanning patients with pain
1. Static images and cine clips
2. Low and high frequency imaging
3. Liver/spleen and liver/kidney comparison
for texture and echogenicity
1. PV patency, direction, velocity
2. HA size, velocity
3. Varices
Gray scale Doppler
Parenchymal Disease:What are we looking for?
1. Increased echogenicity
a) Diffuse
b) Patchy
2. Coarse echotexture
a) Reticular echoes
b) Regenerating nodules
Echogenicity and echotexture
Contour and size
1. Overall length
2. Focal hypertrophy
3. Focal atrophy
4. Contour: wavy, nodular
1. Gray scale
a) Ascites, pleural effusion
b) Splenomegaly
2. Vascular
a) Varices
b) Direction portal flow
c) Velocity, waveforms in
HA, PV, HV
Signs of portal hypertension
Einstein Liver US ProtocolAdapted from ACR US LI-RADS
Longitudinal images
• Left lobe
• Left of midline
• At midline with aorta
• With IVC
• With LPV
• Right lobe
• With gallbladder
• With right kidney
• Include right
hemidiaphragm and
adjacent pleural space
• Far lateral
• MPV in B-mode, color and
spectral Doppler
• Common bile duct
Transverse images
• Dome with hepatic veins
• Right liver edge
• Left liver edge
• Left lobe
• With left portal vein
• Falciform ligament
(assess for patent
paraumbilical vein)
• Main portal vein bifurcation
• Right lobe
• With right portal vein
• With main portal vein
• With gallbladder
• With right kidney
• Near liver tip
Additional views:
• Wide FOV of liver
• Liver/spleen
comparison
• Spleen
measurement
• High frequency R
and L lobes for
contour and
parenchyma
• R and L lower
quadrants to assess
for ascites
Cine loops
• Sagittal left lobe midline to left liver edge
• Transverse subcostal through porta hepatis, superior to inferior
• Transverse right lobe superior to inferior
• High frequency linear transducer, left and right lobes
Large FOV cine loop sweeps
Sagittal left
Begin at patient midline
and scan to left liver
edge
Transverse subcostal
large FOV from below
heart through porta
hepatis
Transverse right
from diaphragm to
inferior aspect of liver
Benefits:1. Interpreting radiologist can search for focal abnormalities
2. Ease of comparison with CT and MRI
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Liver Spleen ComparisonFor echogenicity and echotexture
• Usually liver echogenicity is ≤
spleen and both have
homogeneous echotexture
• Even when enlarged 2° to portal
hypertension, splenic echogenicity
and echotexture usually normal
• Renal appearance may be
abnormal since patients with
chronic liver disease often have
altered renal function, thus renal
comparison may not be sensitive
• In most patients liver and spleen
are not adjacent (as in this
example)
• We use split screen technique
without changing machine settings
for liver spleen comparison
Left lobe hypertrophy in cirrhotic patient allows
Liver/spleen comparison in single image
Split screen technique in same patient
Liver
Spleen
Benefit of Liver spleen comparisonCompare echogenicity and echotexture in 4 different patients
Normal: Liver slightly less echogenic than spleen
Homogeneous echotexture at low and high frequency
Bx proven steatohepatitis: Liver echogenicity = spleen,
slight heterogeneity, confirmed on high frequency
Moderate steatosis: Liver echogenicity > spleen in 2013
Liver = spleen in 2016 after RYGB and weight loss
Mild steatosis: Liver echogenicity > spleen;
cannot compare to kidney because renal
echogenicity is due to CRF
1 3
2 4 2013
2016
Echogenic liver at low frequency
echogenicity
sound attenuation
Smooth contour
echogenicity
reticular echoes
Smooth contour
Steatosis Hepatitis and fibrosis Cirrhosis
1 2 3
echogenicity
Regenerating nodules
Nodular contour
High frequency supports more specific diagnosis
Benefit of low frequency and wide field of
view for global contour abnormalities
Indentation of posterior inferior surface of R lobe at
level of R kidney 2°enlargement of caudate lobe and
atrophy of right
Interlobar atrophy and lateral segment hypertrophy
Low vs. high frequency imaging for contour
abnormalities in same patient
Global Surface
Inferior R lobe atrophy Caudate lobe
hypertrophy
Smooth anterior
R lobe
Nodular surface may have variable distribution
Interlobar atropy
Nodular posterior R
lobe and anterior L lobe
Cirrhosis: US-CT comparison 1
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Cirrhosis: US-CT comparison 2 Cirrhosis: US-CT comparison 3
High frequency static images and cine clips
help visualize regenerating nodules
Slightly nodular
contour
Homogeneous
echotexture
More confident interpretation of cirrhosis using these techniques
5-1 MHz
12-3 MHz
Nodular surface with multiple 1-2 mm regenerating
nodules
9-2 MHz
12-5 MHz
Slightly nodular
contour
Significant
heterogeneity
Regenerating nodules, definite nodular contour
Two different patients
Mild hepatic heterogeneity and
possible GB wall thickening
Is this cholecystitis?
GB wall thickening, nodular surface and
regenerating nodules;
Inter-lobar atrophy results in “naked GB”
Cirrhosis causes GB wall thickening!
12-5 MHz5 -1 MHz
Benefit of high frequency imagingRUQ US for abnormal
LFTs and pain
Progression of cirrhosis on 12-5 MHz imaging
2016 US and MR2013 US and CT 2014 US
Smooth contour
Normal echogenicityWavy contour
Heterogeneity
Nodular contour
Tiny hypoechoic regenerating
nodules on US with corresponding
hypointense foci on MRLiver BX 4/2014:
Chronic hepatitis with
Bridging fibrosis
Liver BX 10/2014:
Cirrhosis with
Extensive fibrosisT1W portal venous phase
Combination of techniquesWide field of view, high frequency
Standard 5-1 MHz: Increased echogenicity
Hepatosplenomegaly
Slightly heterogeneous echogenic liver
Wide FOV 12-5 MHz
Nodular surface
Nodular heterogeneity
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Benefit of high frequency imaging for diagnosis of
cirrhosis when liver surface is smooth
Slightly heterogeneous
echotexture with smooth contour
5-1 MHz
Though surface is smooth, regenerating
nodules suggest cirrhosis
12-5 MHz
Coronary varices
Smooth liver
Normal spleen
Biopsy proven
cirrhosis
Combination of low and high frequency, color Doppler
and cine clips allow more specific diagnosis
Nodular contour ?
What are these linear
echogenic bands ?
5-1 MHz 12-5 MHz
Definite nodular contour
Linear echogenic bands in
transverse
Superficial varices
Definitive cirrhosis and
portal HTN at 12 MHz
Narrow, thick walled CHD
Echogenic bands parallel to portal veins =
dilated sludge filled ducts
Primary Sclerosing
Cholangitis
Other findings related to cirrhosis
and portal hypertensionRight pleural effusion
Nephromegaly
SplenomegalyAscites with 3D surface rendering
2 different patients
Wall thickening of colon and jejunum
Colopathy and enteropathy
Sag R colon Sag jejunum in LUQ
Doppler changes with chronic
liver diseaseHepatic Artery Hepatic Veins Portal Vein
1. Variable changes
to R.I.
2. ↑ velocities reflect
shift to more
arterial flow as
portal HTN
worsens and PV
flow decreases
3. Dilatation
1. Decreasing phasicity1
a. a wave ↓ baseline
b. Ultimately
monophasic
2. Spectral broadening:
loss of normal spectral
window
3. Diminutive size
1. Slow flow, < 16 cm/sec
2. Abnormal direction
a. Complete or partial
hepatofugal
3. Absent
a. Stasis
b. Benign thrombus
c. Malignant thrombus
4. Dilatation1 Obtain waveform during mild inspiration
Valsalva maneuver can reduce phasicity
NORMALa
PV
VaricesParaumbilical
Coronary
Spleno-renalCavernous transformation
after chronic PV thrombosis
Gallbladder varices due to chronic PV thrombus
T1W post contrast
TRV
Elevated hepatic
artery velocity 2°
increased arterial flow
PV direction remains
hepatopetal with normal
velocity
Para-umbilical varix
Loss of phasicity in
hepatic veins due
to stiff liver
Doppler in patient with cirrhosis
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Beware:
Diffusely ↑ size of intrahepatic arteries can have appearance similar
to biliary dilatation in gray scale images
Hepatofugal flow in
Splenic V and MPV
Splenorenal varices
Trv splenic vein
Doppler in patient with cirrhosis
Low velocity hepatopetal
flow in main PV
Reversed flow in left PV
“No flow” in PV at routine
PRF settings
Patent PV with slow flow at
lower PRF
Low velocity in PV
Intermittently reversed flow
Hepatofugal
Hepatopetal
Doppler in 3 different patients with cirrhosisSubtle and variable reversals of portal flow, low velocities
HCC: Diffuse and FocalACR US LI-RADS
• Terminology: Recommend use of “Observation” for any
focal region that differs from background parenchyma in
echogenicity and echotexture
• US Scores for:
– Detection
1. Negative- No observation or definitely benign
2. Sub-threshold- Observation <10mm or not definitely benign
3. Positive- Observation ≥ 10mm, not definitely benign, new thrombus in PV
– Visualization: extent of heterogeneity, ability to adequately
penetrate to diaphragm
A. Minimal limitations
B. Moderate limitations
C. Severe limitations
Remember: US LI-RADS is for detection of “Observations”
Contrast CT/MRI and Contrast US are tests
for definitive diagnosis and characterization of HCC
Importance of R and L lobe comparison
to appreciate diffuse HCC
Typical cirrhosis:
1. Nodular contour
2. Coarse echotexture
3. Normal population
of vessels
Infiltrative HCC =
“Adenomyosis of the Liver”
1. Considerable
heterogeneity
2. “Venetian blind” shadowing
3. Indistinct echogenic
nodularity
4. Absent vessels
STOP
Evaluate
vessels!
Same
patient
Uterus with adenomyosis
R L
Diffuse portal “tumor in vein” confirms
suspicion of diffuse HCC (US LI-RADS 3)
Branching pattern of echogenic “nodules”
more easily appreciated as tumor in vein
by using cine clips
Expanded R PV filled with tumor that
demonstrates arterial flow
Same patient
Localized infiltrative HCCPoorly defined region of tumor with corresponding PV tumor in vein
PV thrombus in same
region as infiltrative tumor(note how tumor bulges capsule!)
Branching of PV with tumor in
vein and subtle difference in
echotexture of tumor more
easily appreciated with cine
clip Arterial enhancement in
PV tumor, difficult to
appreciate
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Focal Observation ≥ 1cm at screeninghistory of Hepatitis C and Cirrhosis
Cine helps categorize Couinaud
segment and assess
relationship to vessels and
ducts
Arterial MRI
Delayed MRI
CT/MRI LI-RADS 5: Classic HCC
Recommend
multiphase
contrast study
(Look carefully on cine for second “observation”)
US LI-RADS Category 3
Small observation on screening US
Solitary 8.4 mm lobulated
echogenic nodule visible
on low and high frequency
MRI arterial phase
hyperenhancement
MRI delayed phase washout
with capsule
MRI was
performed
US LI-RADS Category 2
Sub-thresholdCT/MRI LI-RADS 4
Note: There is shift
towards US rather than
CT/MRI F/U for sub cm
observations to decrease
false positive rate of US
screening and due to size
(< 1 cm does not meet
criteria for LI-RADS 5)
Small observation on screening US
7 mm hypoechoic observation
in left lobe
MRI T1 pre
T1 arterial phase
T1 delayed
What to do
when not
visible
on MRI ?
Resume US screening
US LI-RADS Category 2,
Sub-threshold
Note: There is shift
towards US rather than
CT/MRI F/U for sub cm
observations to decrease
false positive rate of US
screening . Observation
< 1 cm does not meet
criteria for LI-RADS 5.
New 1.4 cm observation on surveillance US
not visible on MRI
Arterial phaseSag L lobe
Portal venous phase 5 minutes
CEUS LI-RADS 3
No washout
Small component enhances similar to
liver, no arterial hyperenhancement
Isoenhancing
Contrast US
Resume US screening
Pitfalls and other issues
• Be wary of making dx of PV thrombosis unless
thrombus is visualized in gray scale
• Multiple tiny regenerating nodules: when to
become concerned for a focal lesion?
– We suggest >5mm
• Lack of correlation between US and MR/CT
– If observation only visualized on US continue US
screening and/or contrast enhanced US
• When is US insufficient for screening/surveillance?
– If unable to penetrate adequately 2º severe steatosis or
extreme heterogeneity
Troubleshooting and Pitfalls
Visualization improved!
C5 R lobe
supine
Poor visualization 2°
obesity
Wavy contour L lobe, Cirrhosis?
Nodularity often not uniform
Check contour both lobes!
Poor visualization 2°
steatosis
C5 penetration
LPO positioning
C5 penetration
When steatosis is severe
and cannot visualize
diaphragm, US is limited
Check R lobe
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• Dedicated screening and surveillance liver US is a highly
specialized imaging technique which benefits from
attention to detail using: – Standardized technique in routine order
– High and low frequency imaging
– Liver/spleen comparison
– Cine clips
• Doppler: Even if formal spectral Doppler is not ordered,
check direction of PV flow and search for varices
• HCC screening– Use wide FOV, compare echotexture of lobes and look for PV thrombus
as clue to infiltrative HCC
Tips from Einstein radiologists:1. “Adenomyosis” of liver may be clue to infiltrative HCC
2. “Naked gallbladder” is a useful sign of inter-lobar atrophy
3. If no color flow in “anechoic” PV on routine settings, make PRF sensitive to R/O thrombus
Summary References
1. Colli A, et al. Severe Liver Fibrosis or Cirrhosis: Accuracy of US for
Detection – Analysis of 300 Cases. Radiology 2003; 227:89-94
2. Hirooka M, et al. Nonalcoholic Fatty Liver Disease: Portal hypertension due
to outflow block in patients without cirrhosis. Radiology 2015; 274: 597- 604
3. Kelly EM, et al. Sonography predicts liver steatosis in patients with chronic
hepatitis B. J Ultrasound Med 2017; 36: 925-932
4. McNaughton DA, Abu-Yousef MM. Doppler US of the Liver Made Simple.
Radiographics 2011;31:161-188
5. Morgan TA, et al. US LI-RADS: ultrasound liver imaging reporting and data
system for screening and surveillance of hepatocellular carcinoma. Abdom
Radiol (2017) DOI: 10.1007/s00261-017-1317-7
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