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Chapter 13 / Energy Devices for Parenchymal Transection in Liver Surgery 161
Inherent limitations of the device remain the need for the operating sur-
geon to feel when the tissue is desiccated–sealed with a gradual compres-
sion of the device. e device diers from other devices as its mechanism of
action is initiated prior to complete closure of the device giving the operat-
ing surgeon feedback on the type of tissue that is being transected.
Salient Dissecting Sealer (Formerly TissueLink Monopolar)
e TissueLink oating ball is a saline-cooled, high-density monopolar
radiofrequency probe used for dissection and coagulation. Saline irrigation
at the tip maintains the surface temperature below 100°C, preventing char-
ring and tissue “sticking,” reducing smoke, and decreasing lateral thermal
spread. e saline facilitates energy transfer between the device–tissue
interface, maintaining contact with the hepatic tissue even when the tip is
moving and evenly dispersing thermal energy. e mechanism of sealing is
primarily by heat and shrinking, and it provides a clean transection bed and
can seal vessels up to 3mm in size. It will isolate larger vessels, which can
then be controlled by other techniques.
TissueLink is useful in transecting cirrhotic livers and in resecting
lesions in close proximity to major vessels. eoretically, the saline cooling
prevents lateral thermal spread, thus making it safer around biliary and
larger vascular structures. It is however expensive and slow. It has been
used in many centers in combination with ultrasonic dissection device.
Various nonrandomized studies showed ecacy in cirrhotic and noncir-
rhotic liver transection with respect to blood loss and postoperative liver
dysfunction, albeit with an increase in operative time. It has been used in
living donor hepatic transection showing superiority in one study over
CUSA and bipolar electrocautery. One randomized study, using water-jet,
ultrasonic dissector and aspirator, and salient dissecting sealer, found that
the dissecting sealer group used less hemostatic agents but was slower
and more expensive than Hydrojet and CUSA. Randomized trials however
have showed no signicant benet over the crush–clamp technique. e
benets of this device remain its hemostatic potential and action, while
not requiring any type of compression. is can be very helpful when per-
forming nonanatomic resections in cirrhotic patients when the hepatic
parenchyma is more brotic that the portal inow or hepatic outow and
thus a crushing technique can lead to more bleeding. e limitations of
the device remain its methodical method of action and limited eciency
when used alone.
PlasmaKinetic Tissue Management System
is system delivers pulsed bipolar energy through the instrument to the
tissue, allowing intermittent tissue cooling, which limits lateral thermal
spread and tissue sticking. e generator detects the optimal settings for
the specic instrument, and there are visual and audible tissue impedance
indicators. e system has two dierent modes: the vapor pulse coagulation
mode and the PlasmaKinetic tissue-cutting mode. In the vapor pulse mode,
high energy is delivered to grasped tissue, creating vapor zones. e current
then travels around the high-impedance vapor zones, following the path of
least resistance. e vapor zones subsequently collapse, and with each new
energy pulse, more and more tissue between the instrument jaws is coagu-
lated, ultimately resulting in uniform coagulation of tissue. It is capable of
sealing vessels 5 to 6mm in diameter and has burst pressure up to three
times the systolic blood pressure with half of the lateral thermal spread
compared to conventional bipolar devices. In a recent study, PlasmaKinetic
was used for hepatic resections in 51 cirrhotic and noncirrhotic livers, with
acceptable morbidity and transection speeds. e authors point to the
Section II / Liver162
statistical similarity between the outcomes of the cirrhotics and noncir-
rhotic patients as evidence that it is ecacious in cirrhotic liver. ere are
various eector instruments including hook, needle, and dissecting and
cutting forceps.
ARGON BEAM COAGULATORS
e argon beam coagulator is a noncontact, monopolar electrocoagulation
device that transmits radiofrequency electrical energy from a handheld
electrode across a jet of argon gas. e argon gas jet clears the eld of pooled
blood and evenly distributes electrical energy to the target tissue. Argon
photocoagulation is used very commonly to control bleeding from the cut
parenchymal edge. It allows for rapid and diuse supercial coagulation
at the plane of transection. It is usually used in conjunction with another
dissecting technique such as Kelly-clysis and CUSA. It cannot be used to
control large vascular and biliary structures, but with its low penetrance
contact coagulation, it is extremely eective in surface hemostasis. Its use
is almost ubiquitous in transplant and cirrhotic settings. ere have been
various reports of bowel injury with its use when used by untrained hands
or because of a lack of understanding of the method of action of the device.
ere remains a myth regarding the potential risk of venous gas embolism,
which can occur in any open case when the central venous pressure (CVP)
is low and/or inadvertent injury to the hepatic outow structure occurs.
We have successfully utilized argon beam coagulation following over 300
laparoscopic cases and have not had a single venous embolism event, and
thus, we believe this risk is unproven when good surgical transection tech-
nique is utilized.
ABLATIVE TECHNOLOGIES
Radiofrequency-Assisted Parenchymal Transection (RF-PT): Habib 4 ×
Radiofrequency (RF) devices have been used for more than a decade to
thermoablate nonresectable hepatic lesions. e Habib was an extension
of this technology. It was one of the rst devices to create a bloodless eld
at the purported site of transection using thermocoagulative properties. It
uses RF probes, which can be inserted into the liver surface. is leads to a
plane of coagulative necrosis to be developed along the line of parenchymal
transection, with subsequent reduction of blood loss and transfusion. is
concept of precoagulation deep in the parenchyma of the liver before tran-
section allows nonanatomical resections. It can seal intrahepatic vessels
and bile ducts. e radiofrequency energy is typically applied in sequen-
tially overlapping segments to ensure adequate hemostasis. is technique,
however, is time consuming and costly. Despite the ability for nonanatomi-
cal resection, it does lead to a large area of hepatic eschar and more tissue
necrosis than other techniques.
In the RF-PT or radiofrequency-assisted parenchymal transection, the
Habib device 4 × has been used widely in various centers. Various nonran-
domized studies showed benet especially in reduction of blood loss and
postoperative complications. However, there have been increasing reports
of liver failure and infectious complications in part due to the wide zone
of ablation that the RF device induces. In some randomized studies and
two meta-analyses, Habib was shown not to be superior to the crush–clamp
technique. Proponents argue that the use of RF-assisted device is especially
useful in cirrhotic livers where traditional transection methods can lead to
signicant more blood loss. is claim has been backed up by at least one
randomized study that showed signicantly lower blood loss and a trend
to decreased complications with the use of RF devices in cirrhotic livers.
Chapter 13 / Energy Devices for Parenchymal Transection in Liver Surgery 163
Itisuseful in cirrhotic patients, but the risks of the large ablation zone lead-
ing to liver failure in these patients with marginal liver reserve need to be
taken into account. Additional challenges with this device for laparoscopic
use are the large trocar that is required and the lack of any type of transec-
tion feature leading to inecient of movements during transection.
Microwave
Microwave energy technology has been used as an ablative therapy in
patients with nonresectable hepatic lesions. Similar to the RF-PT device,
it utilized the precoagulation principle. A microwave tissue coagulator
(Alfresa Ind., Osaka, Japan) generates a 2,450-MHz microwave, which is
transmitted to a monopolar type of needle electrode, called a microwave
scalpel, by way of a coaxial cable. is endoscopic surgical device has a
hand piece with needle-shaped monopolar applicators. Microwave emis-
sion is started after the liver tissue is punctured with a microwave probe or
scalpel. Molecular excitation by microwave causes thermal energy, which
results in zone of tissue coagulation around the microwave scalpel. e
coagulation region reaches a depth equal to the length of the scalpel. It can
be recognized as a supercial yellow-whitish coagulation zone approxi-
mately 1cm in diameter.
Microwave precoagulation has been gaining favor among some sur-
geons. It has shown to be a safe and eective mode of precoagulation before
transection in a nonrandomized study with respect to bile leak, hospital
stay, and blood loss as compared to historical controls with other transec-
tion devices. It has a smaller ablation zone compared to radiofrequency
ablation. is technique however is time consuming and needs precoagu-
lation as a separate step. No randomized controlled trials have compared
microwave to other technologies or to the clamp–crush technique. Current
technologies have not been optimized for precoagulation and transection
with the use of microwave and thus remain limited to open resections.
DISSECTION-ONLY DEVICES
Ultrasonic Dissectors: (CUSA)
e Cavitron Ultrasonic Surgical Aspirator (CUSA) is a dissecting device
that uses ultrasonic frequencies to fragment tissue. In combination with
the aspiration of the dissected contents (i.e., hepatic parenchyma), CUSA
skeletonizes small vessels and bile ducts allowing control by clips, ligatures,
or other energy devices. Utilizing a hollow titanium tip that vibrates along
its longitudinal axis, fragmentation of susceptible tissue occurs while con-
currently lavaging and aspirating material from the surgical site. e CUSA
selectively ablates tissues with high water content such as liver paren-
chyma, glandular tissue, and neoplastic tissue. Among CUSA’s benets, it
provides a very well-dened transection plane, which is useful in situations
of close proximity between tumors and major vascular structures. Also, it
can be used in the cirrhotic as well as noncirrhotic livers and is associated
with a low blood loss and low risk of bile leak.
Noninferiority studies comparing CUSA to the clamp–crush t echnique
have shown similar outcomes. One of the rst randomized studies compar-
ing the ultrasonic dissector versus the clamp–crush technique showed that
the ultrasonic dissector is more frequently associated with tumor expo-
sure at the resection margin and with incomplete appearance of landmark
hepatic veins on the cut surface. Subsequent retrospective studies showed
superiority with respect to blood loss but with longer operating times com-
pared to conventional surgery. Other studies comparing CUSA with water
dissectors (Hydrojet) showed CUSA to have longer transection times but
Section II / Liver164
less blood loss. Several RCTs looking at the eectiveness have not shown
any improvement in operative times, blood loss, or complication rates with
CUSA. Proponents of CUSA highlight the selective vascular isolation and
visualization of the CUSA, the clean operative eld, and the fact that it has
been used clinically for close to two decades. Opponents argue that is takes
longer, has similar transection outcome, and is expensive. e incidence
of air embolism with ultrasonic dissectors is also a common phenomenon,
which is usually asymptomatic but may lead to adverse outcomes.
Water-Jet Dissector (ERBEJET 2, ERBE USA Inc., Marietta, GA)
is technique employs a high-pressure water jet to break apart the liver
tissue and selectively isolate small vascular and biliary structures, poten-
tially decreasing blood loss. ese vessels and ducts must then be ligated
and divided individually according to preference. Its advantage is hav-
ing a precise delineation of the transection plane, which can be used to
expose major vessels eectively, especially in the context of closely adjacent
tumors. Water-jet dissection does not use thermal energy and thus spares
the surrounding tissue from any thermal damage. Water-jet dissection was
noted in one randomized study to be superior to CUSA with regard to tran-
section speed and blood loss, Pringle time, and operative duration. A ran-
domized trial comparing four techniques of clamp–crush (under pedicle
control), CUSA, Hydrojet, and dissecting sealer was recently conducted.
e clamp–crush method was noted to be superior in transection speed,
blood loss, transfusion rate, number of ligatures, and transection time. e
ultrasonic and water-jet dissection devices have remained a useful tool for
precoagulation dissection and thus do require an additional coagulation
device and cosurgeon of adequate experience to assist during the transec-
tion steps. is requirement can limit eciency, but overall remains a very
safe and eect method of dissection.
ULTRASONIC CUTTING AND COAGULATING DEVICE
e ultrasonic cutting and coagulating surgical device (Harmonic scalpel,
not to be confused with ultrasonic dissector such as CUSA) converts sound
energy into mechanical energy at the functional end of the instrument.
Apiezoelectric crystal in the hand piece generates vibration at the tip of
the active blade at 55,500 times per second. is leads to production of heat
from rupture of hydrogen bonds, which leads to denaturation of proteins
at tissue temperatures of 60°C to 80°C, resulting in coagulum formation
without the desiccation, charring, or smoke caused by conventional elec-
trosurgical methods. e main disadvantages of Harmonic scalpel are the
limited ability to coagulate vessels larger than 3 to 5mm, increased cost of
disposable instruments, and potential for extensive thermal spread at high
energy levels (level 5) for more than 5 seconds. e quality of vessel seal also
depends on the amount of tissue tension delivered and the setting used,
and in this aspect, it is surgeon dependent.
Use of Harmonic scalpel has become more widespread in the era of
laparoscopic surgery, with varied uses from thyroid surgery to upper gas-
trointestinal (GI) tract procedures. Harmonic scalpel is capable of sealing
vessels from 3 to 5mm and has shown to have less lateral thermal spread
than conventional electrosurgery and minimal smoke formation or char-
ring. It is also a versatile instrument, allowing the surgeon to dissect, cut,
and coagulate using one instrument. e presence of an active exposed
blade can be both an advantage in mobilizing coapted tissue but can also
be dangerous if unintentional tissue contact with the active blade occurs.
Initial reports used Harmonic scalpel in both open and laparoscopic liver
Chapter 13 / Energy Devices for Parenchymal Transection in Liver Surgery 165
resections, with no biliary leakage reported in a study of 41 patients. In
contrast, a nonrandomized study showed an increased rate of postopera-
tive bile leakage, raising some concerns of its safety sealing biliary struc-
tures. Another large published series comparing clamp–crushing with
ultrasonic plus Harmonic scalpel dissection showed longer operative time,
but with a reduced blood loss and a lower rate of biliary stula. However,
the retrospective method of the study and the relatively long period of
inclusion may have biased these results against the clamp–crush tech-
nique. e merits of Harmonic device in cirrhotic livers, or in preventing
bile leaks, remain to be proven. Similarly, the device has not been opti-
mized for prolonged 20- to 30-second continuous use during transection,
and thus, care should be taken to avoid collateral heat transfer and to
ensure device integrity.
COMPARISON
e techniques of nger fracture technique or the use of Kelly-clysis along
with individual ligation with clips or sutures for vascular and biliary struc-
tures have long been employed in liver resection. ere has since been an
increase in the use of precoagulation, or making the transection plane
avascular with coagulation devices before transection. Examples of preco-
agulation devices are microwave and radiofrequency energy devices, which
ablate and coagulate along the transection plane leaving a rim of avascu-
lar tissue. Broadly speaking, Ligasure, Enseal, and Harmonic devices use
the precoagulation principles to eect subsequent parenchymal division.
is is in contrast to resistance-modulated devices, which fragment low-
resistance tissue (hepatic parenchyma) preserving brous (high- resistance)
components such as vessels and bile ducts for subsequent ligation by the
surgeon. ese vascular-sparing structures include the ultrasonic dissector
(CUSA) and the Hydrojet devices.
e advent of laparoscopy and its increased use in hepatic surgery led
to an increased need for improved transection technology. e use of inow
control in laparoscopic surgery is less common than with conventional
techniques due to technical diculty. Newer transection devices have
allowed parenchymal transection without the need for prolonged inow
control in laparoscopic procedures.
Although the Kelly-clysis or clamp–crush technique has long been
the cornerstone of parenchymal transection in combination with inow
control, there is a greater risk of blood loss associated with this technique,
when performed incorrectly. Despite a plethora of published literature
with respect to parenchymal transection devices, no clear consensus of the
optimal device exists. One of the major problems encountered in perform-
ing trials in this setting is rapid advance of technology. Newer variations
of existing technology and renements in current devices do not present
enough time for planning and conduct of appropriately powered trials.
Again, when these trials do happen, they are quickly outmoded by a more
novel technology. is is due to the constant feedback from the operator
of the devices and manufacturers trying to retain a niche market. Also,
the operative mortality is about 1% in recent studies with a similar low
morbidity of 8%. erefore, sample size needed for adequately powered
randomized controlled trials using surgery-related mortality or specic
complications as a primary end point is very high, and most single-center
studies are unable to reach those numbers. Multicenter trials are marred
by nonuniformity of technique, which can lead to aberrant interpretations.
At this current point in time, no specic claims of superiority can be made
based on the evidence-based literature of one energy device over another.
Section II / Liver166
Published studies have mixed results and design aws and are underpow-
ered. In an attempt to resolve this issue, a few meta-analyses have been
performed; these have showed no clear benet of one device over another
or in fact even over the conventional clamp–crush technique. In this void
of denitive literature or consensus, the individual surgeon’s technique,
prior training, and familiarity with the device are the key to maintain the
current quality standards for hepatic transection and postoperative mor-
bidity and mortality.
In summation, most parenchymal transection devices have certain
advantages and niche users. Ligasure has the most published literature, is
capable of sealing vessels up to 7mm, has low lateral thermal imprint and
spread, and is easy to use. Similarly, the newer Enseal device has a similar
vessel-sealing ability, with lower thermal imprint, uses compression forces
in addition, and can cut and coagulate at the same time but needs a trained
measured input from the user. Harmonic scalpel is often used in combi-
nation with CUSA, Hydrojet, or the clamp–crush technique, but is not
suitable for controlling larger biliary or vascular structures. Using of resis-
tance-modulated devices, such as CUSA or Hydrojet, provides clean lines of
transection. Proponents argue that in performing hepatectomies in which
small margins are anticipated, the Harmonic scalpel could be benecial
in achieving R0 resections. Primary precoagulation technology of RF-PT
(Habib) is popular among many centers, with reported bloodless transec-
tion eld especially for nonanatomical resections but leaves a large area of
necrosis in its wake. Microwave devices are newer energy platforms with a
smaller zone of necrosis. Some large centers use salient dissecting sealer
often in conjugation with another hemostatic device and prefer the clean
transection with minimal thermal spread. It would be remiss to discuss
parenchymal transection without mentioning hepatectomy with staplers.
Stapler-directed parenchymal transection is safe and fast and leads to less
blood loss and shorter hospital stay. Initial studies have yet to be conrmed,
and the increase in cost may deter some surgeons. e CRUNSH study is
a randomized controlled trial to evaluate stapler hepatectomy versus the
clamp–crush technique with the primary end point being intraoperative
blood loss; this trial has recently been completed.
Most of these devices when used properly are safe and can facilitate
parenchymal transections. erefore, the choice of hemostatic assist tech-
nology in liver transection should be based on individual surgeon prefer-
ence, training, and practice setting. Surgeons should use mentors, industry
workshops, animal labs, and current literature to train themselves to the
device(s) they use. As a word of caution, some of these powerful energy
devices, if used inappropriately, can have severe consequences. For exam-
ple, in aberrant anatomy, or anatomy distorted by tumors, large vascular or
biliary structures could be easily sealed o with disastrous consequences
(Table 13.1).
Our Perspective
e published literature in hepatic parenchymal transection is heteroge-
neous. Some technologies have been shown to be superior in histologic
models and animal studies, but randomized controlled trials or similar
high-quality clinical data do not exist. At this point, no single energy source
has shown to be superior to others, and it behooves the operator to be aware
of the risks and benets of the technology that they are using. Currently,
many surgeons are using an “energy device”–clysis technique in which they
replace the Kelly clamp with hemostatic device as the crush–clamp device.
is was originally used with harmonic focus and was described as focus-
clysis but is being used with other devices.
Chapter 13 / Energy Devices for Parenchymal Transection in Liver Surgery 167
Ligasure Enseal PK-Gyrus Harmonic
Mechanism Bipolar Bipolar Bipolar Ultrasonic shear
Vessel size Up to 7 Up to 7 5 5
Lateral thermal spread 2–3 1 2–6 1
Burst pressure (2–3mm) 744 1,025 910 789
Burst pressure (4–5mm) 1,261 927 647 390
Burst pressure (6–7mm) 645 720 284 532
Seal times (2–3mm) 2.8 4 2 4
Seal times (4–5mm) 3 6.8 4 3.9
Seal times (6–7mm) 3.5 8.25 4.5 5.2
Failure rates 0–13.3 0–5.8 11–40 0–22
Smoke/vapor (ppm) 12.5±3.6 21.6±5 74.1±12 2.9±0.6
Operator-dependent sealing No Yes No Yes
Tactile feedback during actuation No Yes No No
Learning curve Minimal Moderate Minimal Moderate
Vessel-Sealing Devices’ Comparison
TABLE
13.1
Section II / Liver168
Our current practice is to use a similar technique in open and laparo-
scopic as well as in cirrhotic livers. e mobilization of the liver is done with
combined use of sharp Bovie dissection and Enseal. Pedicle clamping is the
exception rather than the norm, and this helps reduce blood loss in patients
who have steatohepatitis or cirrhosis. After performing intraoperative
ultrasound and marking the planned line of liver transection, a combined
crush and vessel sealing is performed with the Enseal device. Dissection is
advanced from the liver surface in 2- to 3-mm layers and 3cm depth, avoid-
ing making “tunnels” or “holes.” e inow and outow tract is controlled
with a single vascular stapler. Our preference for the Enseal device is due
to its high-burst pressures, low lateral thermal spread, ability to engage the
coagulation without locking or clamping down the instrument, uniform
application of pressure along the length of the jaws, comparative cost e-
cacy and the ability to use the same device across a spectrum of liver resec-
tions including open or laparoscopic cases.
Suggested Readings
Gurusamy KS, et al. Techniques for liver parenchymal transection in liver resection.
Cochrane Database Syst Rev 2009;(1):CD006880.
Kluger MD, Cherqui D. Minimally invasive techniques in hepatic resection. In:
Jarnagin WR, Blumgart WH (eds.), Blumgart’s surgery of the liver, pancreas and
biliary tract, 5th ed. Philadelphia, PA: Elsevier, 2012.
Newcomb WL, et al. Comparison of blood vessel sealing among new electrosurgical
and ultrasonic devices. Surg Endosc 2009;23(1):90–96.
Pamecha V, et al. Techniques for liver parenchymal transection: a meta-analysis of
randomized controlled trials. HPB(Oxford) 2009;11(4):275–281.
Rahbari NN, et al. Clamp-crushing versus stapler hepatectomy for transection of the
parenchyma in elective hepatic resection (CRUNSH)—a randomized controlled
trial (NCT01049607). BMC Surg 2011;11:22.
169
INTRODUCTION
Worldwide, hepatocellular carcinoma (HCC) is the fth most common can-
cer and a leading cause of cancer-related mortality. e major risk factors
for HCC include presence of cirrhosis and chronic viral hepatitis due to hep-
atitis C virus (HCV) and hepatitis B virus (HBV). HBV is the predominant
risk factor in the developing world, whereas HCV is the major risk factor in
the United States. HBV and HCV coinfection as well as human immunode-
ciency virus and HCV coinfection may accelerate the development of HCC.
Nonalcoholic fatty liver disease or nonalcoholic steatohepatitis (NASH) is
commonly seen in obese and diabetic individuals and is currently on the
rise worldwide and may become a major cause of HCC in future. HCV and
NASH account for majority of cases of HCC in the United States. Alcohol,
although not a mutagen itself, can cause HCC through alcohol-induced
cirrhosis and can act synergistically with other risk factors, including viral
hepatitis. Aatoxin B1 exposure, autoimmune disorders such as primary
biliary cirrhosis and autoimmune hepatitis, and several inherited liver dis-
orders such as hemochromatosis, Wilson disease, alpha1-antitrypsin de-
ciency, hereditary tyrosinemia, and glycogen storage disorders, although
rare, can also predispose to HCC.
HCC is the result of chronic injury to the liver cells leading to repeated
cycles of cell damage and proliferation with accruals of several genetic and
epigenetic changes. Major molecular alterations in HCC include TP53 muta-
tion (approximately 50%), Wnt–beta-catenin signaling pathway mutations
(20% to 40%), activation of the insulin-like growth factor signaling pathway,
and PI3/PTEN/AKT signaling pathway activation. e PI3/PTEN/AKT
pathway plays a role in cell invasion through activation of MMP-9; there-
fore, kinases in this pathway could prove to be exciting therapeutic targets.
SURVEILLANCE AND DIAGNOSIS
Several societies including the American Association for the Study of Liver
Diseases (AASLD) and the National Comprehensive Cancer Network have
published guidelines for screening and surveillance of HCC. e AASLD
prefers the use of term surveillance over screening for early detection of
HCC as it involves repeated use of screening test at repeated intervals.
Surveillance for HCC is indicated in all cirrhotic patients. Surveillance is
also recommended for other specic groups such as hepatitis B carriers
with positive family history of HCC and those with high HBV DNA levels.
Both radiologic and serologic tests are used for surveillance of HCC in
the above-mentioned populations. Ultrasound (US) examinations and alfa-
fetoprotein (AFP) levels are the most widely used methods for surveillance.
A surveillance interval of 6 months is based on tumor doubling times of
approximately 6 months.
Hepatocellular Carcinoma
Mashaal Dhir and Chandrakanth Are
14
Section II / Liver170
Among the serologic methods, AFP is the most commonly used diag-
nostic test although sensitivity and specicity vary with the size of the
nodule and the cuto values utilized. Sensitivity and specicity range from
55% to 60% and 88% to 90% for a cuto value of 20 μg/L compared to 17%
and 99.4%, respectively, for a cuto value of 400 μg/L. In addition, AFP may
be elevated in patients with intrahepatic cholangiocarcinoma. erefore,
per AASLD, diagnosis should rest on the radiologic and histopathologic
criteria, and AFP alone is considered as an inadequate screening test for
HCC. US is the most commonly recommended test overall for surveillance
with sensitivity (65% to 80%) and specicity (48% to 94%) varying depend-
ing on the size of the nodule. Importantly, US is operator dependent, and
all focal lesions on US should be veried using four-phase multidetector
CT (MDCT) or a dynamic contrast-enhanced MRI as these modalities have
higher sensitivity (89%) and specicity (99%) for lesions greater than 1cm.
A contrast-enhanced study is required to demonstrate the typical “wash-
out” of the contrast seen in HCC. HCC has arterial blood supply exclusively,
whereas the rest of the liver has both portal venous and arterial supply. In
the arterial phase, HCC enhances more than the liver as it has only arterial
supply, whereas arterial contrast in nontumorous liver is diluted by the por-
tal venous blood. In the venous phase, HCC enhances less than the liver as
it has no venous blood supply and the arterial blood owing through HCC
no longer contains contrast, whereas the nontumorous liver is enhanced by
contrast in the venous blood. is phenomenon is known as “washout” and
is characteristic of HCC. A four-phase study (unenhanced, arterial, venous,
and delayed—MDCT or dynamic MRI) is required to document this radio-
logic nding. Figure 14.1 summarizes the AASLD-recommended diagnostic
algorithm for suspected HCC (Fig. 14.1).
HCC
HCC
< 1 cm
> 1 cm
Repeat US at 3 months
Stable
Yes
Yes
Growing/changing
character
Investigate
according to size
No
4-phase MDCT/ dynamic
contrast enhanced MRI
Arterial hypervascularity AND
venous or delayed phase
washout
Other contrast enhanced
study (CT or MRI)
Arterial hypervascularity AND
venous or delayed phase
washout
Biopsy
No
FIGURE 14.1 Algorithm for investigation of small nodules found on screening in patients at
risk for HCC. Adapted from AASLD practice guidelines 2010. Bruix et al. 2010, with permission.