Ultrasound-Guided Biopsies in the Abdomen and Pelvis

24 Pages·2008·7.45 MB·English

REVIEW ARTICLE
CME ARTICLE
Ultrasound-Guided Biopsies in the Abdomen and Pelvis
Thomas C. Winter, MD, Fred T. Lee Jr, MD, and J. Louis Hinshaw, MD
HISTORY
Abstract: Ultrasound-guided biopsies in the abdomen and pelvis
Although primacy is notoriously difficult to accurately
are generally more effective, safer, faster, and cheaper than those
assess, some of the earliest ultrasound-guided procedures
performed under computed tomography guidance. This manuscript
were reported in 1972 by Goldberg and Pollack1 with the
will discuss multiple aspects of sonographic biopsies performed
demonstrationoftheirdedicatedaspirationtransducer.2Com-
between the diaphragm and the symphysis pubis. We begin with
puted tomography (CT) followed closely behind, with the
systems issues, patient preparation (including bleeding profile and
first reported CT-guided biopsy performed by Alfidi et al2 in
anticoagulantuse),painmanagement,andinfectionprecautions.The
1975.3 Ultrasound-guided needle placement grew steadily in
procedureitselfisthenanalyzed,includingneedleguidance,therole
theensuingdecades.TheaptlyentitledarticleofDoddetal,4
of the sonographer, image optimization, patient positioning, core-
BSonography: The Undiscovered Jewel of Interventional
versus fine-needle aspiration, coaxial versusindividual pass, needle
Radiology,[ led to even more popularity for sonographically
technique, and postprocedure management. Issues specific to dif-
guided procedures.
ferentsitesarethendiscussed:liver,spleen,pancreas,kidney,adrenal,
bowel,retroperitoneumandmesentery,andthepelvis.Wefinishwith
adiscussionofcomplications,futuretrends,andabriefsummary. INDICATIONS
The reasons for percutaneous biopsy are broad and
Key Words:ultrasound,biopsy,guidance, sonography
expanding.These include theneed for tissue characterization
(UltrasoundQuarterly 2008;24:45Y68) of an abdominal mass, confirmation of metastatic disease to
direct therapy or counsel patients, confirmation of a specific
LEARNING OBJECTIVES tumor type for a clinical trial (a very large potential future
1. Identify patientselection and preparation. application of percutaneous biopsy as cancer treatments
2. Describe optimal biopsy technique. become more specific for different tumors), evaluation for
3. List potential complications. infection in a fluid collection, evaluation for parenchymal
disease in native organs (typically the kidney and liver), and
Theadventofpercutaneous image-guided biopsy hasbeen evaluation for transplant organ rejection. As abdominal
a huge boon to patients, generally sparing them the radiologists, we appreciate the potential advantages of high-
morbidity of operative procedures for tissue characterization. tech, noninvasive imaging; having said that, we definitely
Ultrasound guidance for these procedures is possible in most agree with one speaker who said Bthe most useful additional
cases in the abdomen and pelvis and is often safer, quicker, MR pulse sequence for lesion characterization is the 18-ga
andlessexpensiveandhasahigherdiagnosticyieldthanother needle[! Another perspective was given by one of the
image guidance modalities. The goal of this article is to memorable characters in Samuel Shem’s classic novel, BThe
presenttechniquesforultrasound-guidedbiopsiesinavariety House of God,[ who stated Bthere is no body cavity that
ofcommonandnot-so-commonscenariosintheabdomenand cannot be reached with a 14-gauge needle and a good strong
pelvis, potentially expanding the use of sonography in these arm.[5
situations and thereby bringing the benefits of ultrasound to What not to biopsy? All medical decision making is a
more of our patients. risk-benefit analysis, so there are very few absolute contra-
indications to biopsy. An excellent relationship and open
ReceivedforpublicationNovember14,2007;acceptedJanuary2,2008. communication with the referring physician are crucial to
Department of Radiology, Abdominal Imaging Section, University of good radiological medical decision making; in addition, the
WisconsinHospitalsandClinics,Madison,WI. radiologist needs to think like a clinician, know his or her
DrWinterhasdisclosedthatheisonthespeaker_sbureauofGEUltrasound.
patient’smedicalhistory,andunderstandtheclinical problem
DrsLeeandHinshawhavedisclosedthattheyhavenofinancialinterestsinor
relationships with any commercial companies pertaining to this educa- tobe solvedby thebiopsy.
tionalactivity. Forexample,performingabiopsyofahighlysuggestive
AllstaffinapositiontocontrolthecontentofthisCMEactivityhavedisclosed hypervascular mass in a cirrhotic liver in the face of an
thattheyhavenofinancialrelationshipswith,orfinancialinterestsin,any elevated>-fetoprotein(AFP)isnotnecessary6Vtheveryhigh
commercialcompaniespertainingtothiseducationalactivity.
likelihood of hepatocellular carcinoma (HCC) in this setting
LippincottCMEInstitute,Inc.hasidentifiedandresolvedallfacultyandstaff
conflictsofinterestregardingthiseducationalactivity. makestissueconfirmationnotworththesmallbutnonzerorisk
Reprints: Thomas C. Winter, MD, Department of Radiology, University of ofbleedingand/orseeding.Inthepast,percutaneousbiopsyof
WisconsinMedicalSchool,E3/311ClinicalScienceCenter,600Highland renal masses was actively discouraged; recent improvements
Ave,Madison,WI53792(e-mail:[email protected]).
in pathological techniques, increasing evidence suggesting
thattheriskoftumorseedingisminimal,andnewtreatments
Copyright*2008byLippincottWilliams&Wilkins forrenalcellcarcinoma(RCC),however,haveledtoamarked
Ultrasound Quarterly & Volume 24, Number1, March 2008 45
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Winteret al Ultrasound Quarterly Volume 24,Number 1, March2008
upsurge in renal biopsies (vide infra). Biopsy of a potential sound guidance for percutaneous liver biopsy. In their deci-
ovarian mass has also been frowned upon; however, when sion analysis, they justify usage of a 78% probability of
the consult is received from a subspecialist gynecologic- obtaining an adequate sample using CT guidance, versus a
oncologist who has reviewed the entire clinical presentation, higher 87% for sonographic guidance (although please note
the biopsy may be in the patient’s best interest and can be thatwearenotawareofarandomizedtrialthatactuallydirectly
easily and safely performed. Similarly, splenic and bowel compares biopsy success rates between CT and ultrasound);
wall biopsies are beneficial and safe procedures in the in our opinion, the ease of real-time confirmation of needle
appropriate setting. passagedirectlythroughthelesionwithultrasoundisoneofthe
primary reasons that ultrasound may have a higher adequate
sample rate. Although time spent on any procedure depends
CHOICE OF IMAGING MODALITY heavilyon patient selection andoperatorexpertise, onestudy
FOR GUIDANCE comparing durations for ultrasound versus CT guidance for
This decision can essentially be simplified to a choice abdominal interventional procedures found an average room
betweenultrasound versusCT. Althoughmagnetic resonance timeof77minutesforultrasoundguidanceversus99minutes
imaging(MRI)guidanceispossibleandhassomeadvantages, (22 minutes longer) for the CT group.11 The advent of CT
in practice the specialized expensive equipment required fluoroscopyhasdecreasedthetimenecessaryforasuccessful
precludes widespread use of this technology. Fluoroscopy is procedure when compared with helical CT; these improve-
widely available but rarely used in soft tissue biopsies of the ments in needle placement times have been estimated at
abdomenandpelvisduetoitsinherentdisadvantagesinthese between 20%9 and 66%.12 However, in one phantom study,
areas. The choice between CT and ultrasound is a multi- ultrasoundwithaneedleguidestillrequiredlesstimethanthat
factorial decision that should be individualized on a case-by- with CT fluoroscopy. This publication also observed that
case basis. In general, a radiologist should consult with the improvementsinneedleplacementtimegenerallydonothavea
referring physician and direct each case to the appropriate significant effect on overall room time (eg, CT fluoroscopy
guidancemodality;thisdirectphysician-to-physiciancommu- versus conventional CT), and hence, the costs incurred. The
nication optimizespatientcare andminimizes the probability inherent ultrasound scan biopsy procedure itself is advanta-
ofpoor outcomes. geous as physicians attempt to cope with the difficulties
In our abdominal imaging section, approximately 98% brought upon by the Bobesity epidemic[ in our society13;
oftheabdominalandpelvicbiopsyproceduresareperformed because of compression applied with the ultrasound probe
using ultrasound guidance. In 2006, 15% of our 16,000 total upontheabdomen,theaveragedistancefromtheskinsurface
annualultrasoundexaminations(thesestatisticsdonotinclude tothelesionwasreducedfromanaverageof8.8cmwithCTto
breastimaging)areproceduresinvolvingultrasoundguidance 4.5cmwithultrasound,14therebyfacilitatingtissuesampling.
for needle placement, whether they are simple thoracentesis
and paracentesis, easy tissue sampling such as thyroid fine-
SYSTEMS ISSUES
needleaspiration(FNA),slightlymorechallengingsolidorgan
Wehavefoundthefollowing5pointstobeveryhelpful
core biopsy, or very difficult subcentimeter interaortocaval
indevelopingasuccessfulbiopsyprogram.First,emphasizeto
lymph node sampling. In general, if the mass or target can
the sonographers the importance of their personally taking
be seen with ultrasound, a biopsy will be performed under
professionalownershipofasuccessfulbiopsyservice.Notall
ultrasound rather than CT.
sonographers wish to embrace the responsibility inherent in
Advantages of ultrasound include real-time imaging
interventional procedures, but those who enjoy it and take it
guidance (safety), speed of use, the ability to compress the
seriouslyaddimmeasurablevaluetothepatient.Second,work
abdomen and get closer to your target, lower cost of capital
closelywithpathologistsandcytopathologiststoensuregood
equipment versus CT, rapid confirmation of complications
communication and useful consultation. Third, a dedicated
(bleeding), higher success rates, portability, and lack of
nurse clinician who is available for patient preparation,
radiationexposuretothepatientandmedicalstaff.Advantages
moderate sedation, and clinician consultation is invaluable.
of CT include visualization of certain structures that can be
Fourth, standardized paperworks (orders, notes, patient
difficult to seewith ultrasound (eg,adrenal, calcified masses,
education, etc) make the day run smoother. Finally, follow-
retroperitoneal structures, lung parenchymal lesions) and the
up is incredibly important for organizational learning. For
comfortofmanyradiologistswithCTtechnology. Computed
everything except thoracentesis, paracentesis, and thyroid
tomography fluoroscopy7 has increased the speed and proce-
FNA, the patient is called the next day to check on their
duresafetywithwhichCT-guidedbiopsiescanbeperformed,
well-being. All procedures are kept in a quality assurance
although the radiation exposure associated with this technol-
database,and complications are tracked.
ogy isnot trivial.8,9
Severaloftheadvantageslistedaboveinsonographyare
self-evident (eg, real-time guidance and portability). Others PATIENT PREPARATION
have been analyzed in a direct fashion. Kliewer et al,10 com- There is an old carpenter’s axiom, Bmeasure twice and
menting on the fact that cost minimization will be one of cutonce.[Thisappliestoimage-guidedbiopsiesaswell,since
the principal determinants of success in the marketplace as properplanningisprobablythesinglemostimportantfactorin
the economics of health care change in our country, found courtingsuccess.Threequotesemphasizethevalueofproper
that CT guidance is 1.89 times more expensive than ultra- preparation:Battentiontothelittledetailsisthefoundationof
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Ultrasound Quarterly Volume 24, Number1, March2008 Ultrasound-Guided Biopsies intheAbdomen andPelvis
excellence[(CoachJohnWooden);Bapintofsweatwillsavea raise the platelet count by 40,000 to 50,000/mL, assuming
gallon of blood[ (Gen George Patton); and Bwithout normal platelet survival. However, many acutely ill patients
execution, vision is just another word for hallucination[15 have shortened platelet survival, patients with large spleens
(Mark Hurd, HP CEO). (eg, cirrhosis) will have lower platelet recovery, and patients
Preparation begins with open communication with the who have autoimmune thrombocytopenia or who are allo-
referring physician, understanding the patient’s history, and immunized to donor platelets may be difficult or impossible
defining what clinical questionis tobe solved. to correct. Proper dosing of FFP is also complex. The
recommendeddoseofFFPis10to20mL/kg,or4to6Uinthe
Patient Preparation: Bleeding Profile average adult (the volume of a typical unit is 200Y250 mL).
Published studies on bleed rates and bleeding profiles However, the dose of FFP needed to achieve a given target
are tenuous at best. Prothrombin time (PT) and partial goes up dramatically as the target INR goes down. Table 3
thromboplastin time (PTT) are routinely ordered worldwide (BPredicted Fresh Frozen Plasma Transfusion Volume, Dose,
forsurgicalpatients,althoughstudiesconsistentlydemonstrate and Expected Factor Improvement for Various Target INR
thelowdiagnosticutilityofthispractice;preoperativePTand Values[) of the 2006 article by Holland and Brooks20 shows
PTT values are poor predictors of abnormal bleeding after thatifonestartswithanINRof6.0,itwilltake1.5LofFFPto
surgicalprocedures.16Indicesofcoagulationintheperipheral bringtheINRto3;2.5LtobringtheINRto1.7;3.5Ltobring
blood have been shown to be unreliable indicators of the theINRto1.5;and4.5LtobringtheINRto1.3.Bottomline,
risk of bleeding after liver biopsy.17 The platelet count is pleaseconsultliberallywithyourlocalhematologyexpertsfor
reproducible but does not assess function, thereby providing issues inthis area.
incompleteandpotentiallymisleadinginformation.18Toquote
from the seminal paper by Erban et al19 discussing the Patient Preparation: Anticoagulant Use
inappropriate use of the PTand PTT tests, BMany physicians This is another areawhere the published literature pro-
consider tests like [these] to be inexpensive, Blittle-ticket[ vides no firm guidance. Many patients are nowon long-term
itemsthatwillprotectthemfromthehazardsoflitigation.[For anticoagulation (heparin and its derivatives, or warfarin) or
the interested reader, Eckman et al18 provide an excellent long-termantiplatelettherapy(eg,aspirin,clopidogrel)orare
reviewregardingscreeningforbleedingrisk.Theyconcluded taking other medications that effect platelet function
thatBIwithoutsyntheticliverdysfunctionorahistoryoforal (eg, nonsteroidal anti-inflammatory agents). The risk of dis-
anticoagulantuse,routinetestinghasnobenefitinassessment continuing therapy (eg,thrombosis) must beweighed against
ofbleedingrisk.[Multiplestudieshaveshownthatobtaininga theriskofanincreasedlikelihoodofabiopsy-inducedbleed.
good history is the most important first step in determining If the clinical service is comfortable discontinuing
whether testing iswarranted. therapy, remember that one must wait ~6 hours after
However, partly because we have a large hepatology/ discontinuing heparin and 8 hours (overnight) after disconti-
liver transplant service and therefore perform invasive nuing low-molecular-weight heparin (LMWH), although one
proceduresonmanypatientswithsyntheticliverdysfunction, recenttrialstatesthatoneshouldconsidergivingthelastdose
andpartlybecauseofthepervasivefearoflitigationdiscussed ofLMWHthemorningofthedaybeforesurgery,rather than
above (Bdefensive medicine[), we routinely obtain an inter- our standard practice of giving the last dose the night before
nationalnormalizedratio(INR)andplateletcountonallintra- surgery;again,though,thischangeshouldbeweighedagainst
abdominalbiopsypatients.IftheINRislessthan1.5andthe the risk of thromboembolism.21 Current recommendations
platelet count is greater than 50,000/mL, we will perform suggestwaiting5to7daysafterdiscontinuingaspirinand7to
almostanyprocedure.Internationalnormalizedratioofgreater 10 days after stopping clopidogrel (Plavix) and ticlopidine
than1.5and/orplateletcountoflessthan50,000/mLprompts (Ticlid).22 Nonsteroidal anti-inflammatory drugs (NSAIDs)
discussion of the biopsy with the referring physician. are a large family, but they do not irreversibly affect platelet
Depending on the location of the target, the type of needle function the way that aspirin does; thus, our hematologists
tobeused,andsoon,adecisionismadewhethertosupplement state that a 24-hour discontinuation before the procedure is
the patient with a transfusion of fresh frozen plasma (FFP) generally sufficient. Warfarin’s duration of action varies
and/or platelets. This is particularly an issue in the biopsy widely, depending on many factors (dose, liver function); in
of cirrhotic livers where both INR and platelets are typically general, we discontinuewarfarin about aweek ahead of time
depressed. We routinely perform diagnostic and therapeutic andrecheckanINRthemorningoftheprocedure.Inonetrial
paracentesis in our population of cirrhotic patients with liver of patients on long-term anticoagulation undergoing colono-
failure if the INR is less than 2 without any infusion of FFP, scopicpolypectomyforpolypsoflessthan1cm,warfarinwas
butwealwayscarefullylookforandavoidtheinferiorepigas- discontinued 36 hours before the procedure, and the average
tric arteries with Doppler before our paracentesis puncture. INR on the day of the procedure was 2.3. No bleeding
WhatistheproperdoseofFFPorplateletstogive?The complications were identified with 41 polypectomies in 21
complexity of blood product replacement requires clinical patients.23 In all cases, reinstitution of medications after a
consultation for proper patient care. Rough guidelines are procedureshouldbeindividualized.22
given here, but realize that the details of this process are Forpatientsinwhomevenshort-termdiscontinuationof
generally beyond the scope of a radiologist’s practice. The warfarintherapyisfelttobetoorisky,ourstandardpracticeis
recommended platelet transfusion dose is 1 U/10 kg of body to discontinue warfarin 5 to 7 days before the procedure and
weightwhenusingrandom-donorpooledplatelets;thisshould replace with LMWH. The LMWH is then discontinued the
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Winteret al Ultrasound Quarterly Volume 24,Number 1, March2008
night before the procedure and restarted the night of the Pain Management
procedure.Warfarin therapy isreinitiated on thenextday.As Adequate pain control is not only a moral imperative,
always, close consultation with the referring service leads to but it has high political priority as well. Pain management
optimal patientmanagement. guidelinesimplementedbytheJointCommissiononAccred-
Shouldoneeverperformaninterventionalprocedurein itation of Healthcare Organizations in 2001 mandate regular
apatientwhohasrecentlytakenanaspirinorNSAID?Thereis assessment of pain and the establishment of policies and
no good evidence-based answer to this commonly occurring procedures that support the appropriate use of pain medica-
and vexing issue. In an informal survey of colleagues who tion.28 A comfortable patient makes an abdominal biopsy a
perform many ultrasound-guided procedures, some labora- much easier procedure all theway around! Painmanagement
tories hold firm to this rule and refuse procedures until the canbesimplifiedintotheBGoldenRule[;howwouldyoulike
requisite time off the drug has passed, primarily over fear of yourselfor your mom tobe treated?There are3 components
litigationinthesettingofanadverseoutcomeratherthanany to adequate pain relief: psychosocial, local anesthesia, and
true scientific sense that this is intrinsically dangerous. Other moderate sedation.
colleaguesshareouropinionthatthisistoosevereapractice,
potentially leading to great patient inconvenience (eg, the
Psychosocial
patientwholives5hoursawayandhastaken2daysoffwork
It has been shown again and again that obvious care,
for aliveror thyroid biopsy,having failedtogetthemessage
concern, and warmth from the medical team result in
that he should discontinue his daily baby aspirin 5 days
decreasedpatientanxietyandperceivedpain.Followcommon
before).Afterathoroughdiscussionofthepossibletheoretical
sense tactics such as making sure that the patient is at a
increase in risk with the patient and giving him or her the
comfortabletemperature,thattherearenobrightlightsinthe
option of rescheduling for a future date, we will typically go
patient’s eyes, and so on. Think about how you prepare the
aheadandperformthebiopsyinthissetting;conversely,inthe
patient. For needles that can be test fired before use (read
retiredpatientwholives10minutesfromourhospitalandfor
the package insert; some of the older devices recommend
whom it is no true inconvenience to reschedule, we will
againsttesting), there isaworld of difference between facing
usually delay the procedure until these drugs have been
the patient with the needle fully visible, close to his face,
stopped for anadequate period.
and stating, Byou will hear a bang from the gun as I fire it,[
There are data to support performing low-risk biopsies
versus turning your back to the patient and blocking viewof
in patients on aspirin or NSAIDs. First, an editorialist states
theneedleandcalmlystating,Byouwillhearaclickfromthe
that maintaining patients who are at substantial risk for
spring in the biopsy device as I test it.[ Consider your word
cardiovascular events on aspirin yields good results for
therapeutic endoscopic procedures.24 Second, many open choice and the subsequent mental state you engender as you
inject the lidocaine. Our orientation packet for the residents
surgical procedures, especially vascular, are performed in
includes a superb article entitled, BCan Words Hurt? Patient-
patients who are anticoagulated or on aspirin due to a
Provider Interactions During Invasive Procedures.[29 Using
favorable risk-benefit ratio. Third, a UK expert writing on
guidelines for liver biopsy states that BIeven though the wordssimilartoBabeesting[orBasharpjab[beforeinstilling
local anesthesia may engender more perceived pain than
ingestion of aspirin and other NSAIDs in the week prior to
neutral statements such as Byou’ll feel cool tingling with the
invasive intervention is a recognised contraindication by
severalauthoritiesIthereare,toourknowledge,however,no spreading of the numbness.[ Although we do not practice
overt hypnosis routinely, there is a body of work on the
convincing data to support this as a contraindication to
percutaneous liverbiopsy.[25 Fourth, a reviewof the issue of medicalutilityofhypnosisinminor(andoccasionallymajor)
invasive procedures; if interested, peruse the Web site of the
low-dose baby aspirin in patients undergoing ultrasound-
AmericanSocietyforClinicalHypnosis(http://www.asch.net/
guided transrectal biopsies of the prostate identifies 2 studies
genpubinfo.htm).
that found no increased risk of hemorrhage in the groups on
aspirin.26 Finally, a Radiological Society of North America
presentation in 2005 looked specifically at the risk of Local Anesthesia
significant hemorrhage resulting from image-guided core We use 1% lidocaine buffered with 8.4% sodium
biopsy in patients taking aspirin.27 In this study of 6073 bicarbonate in a 9:1 ratio. Although somewhat controversial,
biopsies,theauthorsconcludedthatBthereisanelevatedrisk the buffering is generally reported to decrease the Bstinging[
of significant bleeding complications in those patients taking sensationofthelidocaineinjection.30Onapracticalnote,the
aspirin atthetime ofpercutaneous biopsy.However,thisrisk rateof injectionisoftenthemostimportantfactorformaking
is small and should not preclude biopsy in most cases.[ In theinjectionmoretolerableVslowisgood.Whenperforming
fact, although not statistically significant, in their subset of localanesthesia,startwithasubdermalinjectionof2to3mL
patients undergoing liver biopsy, the hemorrhage rate in of lidocaine using a 30-gauge needle (note how small this is,
patients taking aspirin was approximately half that of those ratherthanthetypicallyprovided22-or25-gaugediameters),
not taking it (0.46% vs 0.93%). In summary, as in all of followed by deeper anesthesiawith a 22-gauge spinal needle
medicine,optimalcareresultsfromtreatingeachpatientasan (through the biopsy guide, if you are using one). This
individual and fully discussing the pros and cons of any techniqueensuresacylinderofanesthesiaalongthepathofthe
potential course of action so that the patient may make an biopsy and gives a Bpreview[ of the biopsy trajectory; the
informed choice. latterisusefulifthereareribsorotherstructurestobeavoided
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Ultrasound Quarterly Volume 24, Number1, March2008 Ultrasound-Guided Biopsies intheAbdomen andPelvis
FIGURE1. Inadvertentlyinjectedairobscuringthetarget.A,WhitearrowonCTdenotesasofttissuemassthatwaslater
biopsyproventorepresentperitonealcarcinomatosisfromrectalcancer.Thehigh-densitystructurejustanteriortothenodule
isahepaticarterialinfusionpump.B,Arrowdenotesnoduleonultrasound.C,Althoughthelidocainesyringewasflushedofair,
thedeadspaceinthenumbingneedleafterthestyletwasremovedcontainedenoughgastoseriouslydegradetheultrasound
image.Notehowthenoduleisnowbarelyvisualizedbehindtheshadowcausedbytheinjectedair.
alongtheway.Makesurethatallairhasbeenpurgedfromthe these doses. Always monitor oxygen saturation, pulse, and
syringe andneedle asaircancause obscurationoftheneedle bloodpressurethroughouttheprocedureandafterwardinthe
or target (Fig. 1)! Be sure to place several milliliters of dedicated recovery area. Oxygen, suction, and airway
lidocainedirectlyontheperitonealsurfaceandattheliver(or managementequipmentshouldbereadilyavailable.Although
other organ) capsule. Do not puncture the liver or other almost never needed if fentanyl and/or midazolam are
visceralorganbecauseanesthetizingtheliverparenchymawill appropriately administered, reversal agents (naloxone and
not decrease the pain of the procedure and may increase the flumazenil) should be easily accessible. Keep your advanced
rate of bleeding. Use lidocaine liberally. We routinely give cardiaclifesupportskillscurrent.
10 mL, and there is no risk of lidocaine toxicity in giving
Infection Precautions
20 mL as necessary. More specifically, the maximum
percutaneousdoseoflidocainewithoutepinephrineinhealthy Todrapeornottodrape?Wealwaysdrapetheprobefor
adults is 4 mg/kg, up to 300 mg. Because there is 10 mg guided biopsies (for thoracenteses and paracenteses, we
lidocaine/mL in a 1% solution, this represents a maximum usually mark the spot and do not use the transducer during
dose of 20 to 30 mL for most patients. Busy physicians take needle placement). I am not aware of any literature that
note:lidocainerequirestimetodiffusethroughthetissues,so documents that this extrastep decreases therisk of infection.
allow a few minutes before biopsy after local anesthetic Infact,severalveryexperiencedcenters ofexcellence(Mayo
administration tominimize discomfort. Clinic, Italian groups) do not sterilely drape the probe unless
thepatientisknowntohaveHIVinfectionandinsteadsimply
Moderate Sedation cleanse and disinfect the transducer before and after each
biopsy;theyhavehadnoknownissueswiththisprotocol.The
Thethirdtoolforpainmanagementismoderatesedation
disadvantages to draping include time, cost, and potential
(previouslyreferredtoasBconscioussedation[).Ifthepatient
degradation of image quality (although the latter is more
is treated appropriately, and copious local anesthetic is
theoretical than real in our opinion). If chemical disinfection
properly administered, moderate sedation is usually not
is used (eg,alcohol, povidone-iodine [Betadine]), ensure that
necessary for routine liver biopsies; however, if a nurse is
the substance used is compatible with the transducer surface
readilyavailable,ifthebiopsylookstobeparticularlydifficult,
and manufacturer’s recommendations.
or if the patient is particularly anxious, we will certainly use
intravenous medications, typically fentanyl (Sublimaze) and
Skin Preparation
midazolam (Versed). We almost never use moderate sedation
for thyroid biopsies, superficial lymph node biopsies, We now use chlorhexidine 2%/isopropyl alcohol 70%
thoracenteses, or paracenteses. Conversely, transvaginal (Chloraprep) rather than povidone-iodine 10% (Betadine).
biopsiesmaybequitepainful,somoderatesedationisalmost Both are adequate, but the former has better antimicrobial ac-
always used here. tivity,doesnotstainoritch,andworksquicker.Readthepack-
If moderate sedation is used, make sure that it is done age insert for application instructions, and take care to apply
safely. Most hospitals now require special credentialing and withaback-and-forthactionforafull30seconds,and then let
privilegingtoperformsedation,andmanyalsorequireconsent air dryVdo not blot or wipe. Only 1 application is required.
for the sedation as well as the procedure itself. The
medications should be administered in small aliquots, Needle Safety
typically50Kgoffentanyland1mgofmidazolam,although Becareful!Thereisaveritablealphabetofpathogensto
in elderly, very sick, or small patients, we will often halve bewaryof.InadditiontoHIV,thereareavarietyofhepatitis
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Winteret al Ultrasound Quarterly Volume 24,Number 1, March2008
FIGURE2. Needlenotfollowingtrajectorypredictedbytheguide.Thislesion(metastasisfrompancreaticcancer,arrowheadinCT
[A])hadtobefine-needleaspirated3timestoreturnthediagnosis(metastaticpancreaticadenocarcinoma).Becausethe20-gauge
needlewasdeflectedbyoverlyingtissues,thefirstpasswaslateral(B)tothelesion(arrowhead).Thenextpass(notshown)was
medialtothelesion,whereasthethirdpass(alsonotshown)wasinthetumor.Arrowpointstotheneedletip.
strains which currently run from hepatitis A through G. The but that this benefit was greatest for inexperienced operators.
most important of these are hepatitis B virus, for which a In our laboratory, most deep abdominal biopsies are
vaccine is available (make sure to check your antibody re- performed using a biopsy guide, whereas superficial biopsies
sponsetoensureyouareadequatelyimmunized),andhepatitis (eg, thyroid, breast, groin) are performed freehand. Remem-
C virus, for which novaccine is available. Despite all of our ber, though, that a guide is just a guide, not a guarantee,
precautions,weaverageabout1needlestickinourlaboratory particularly with thin needles, cirrhotic (hard) livers, and/or
every year. Protect yourself, the sonographer you work with, any firm overlying structures (eg, ribs) that may deflect the
andthecytopathologistyouarepassingtheneedleto. needle(Fig.2).Ifconsistentdeviationtoonesideisobserved,
one can adjust the projected trajectory outside the lesion to
OTHER BIOPSY ISSUES compensate for the amount of deviation (similar to compen-
sating for wind or elevation issues through the site of a rifle)
Guidance
(Fig. 3).
Mechanicalbiopsyguideversusfreehand.Bothsystems
work well if the operator is comfortable with the technique. Role of the Sonographer
Freehand technique offers the possibility of better needle Some laboratories have the radiologist guide the pro-
visualization (more specular reflection if angles are chosen cedure while the needle is placed; this requires more manual
appropriately) but generally requires more skill and experi- dexterity but allows more direct control of needle placement.
ence.Inonestudy,aphantommodeloflesions inthehuman However, in our laboratory, the sonographers scan and guide
liver with simulated overlying ribs was used to compare biopsyproceduresforseveralreasons:theyareusuallythebest
freehand and probe-guided techniques31; the authors con- technical scanners; the large number (~2400/yr) of needle
cludedthattherewasatimebenefittotheuseofprobeguides guidance procedures done by ultrasound in our laboratory
FIGURE3. Compensatingforneedledeviation.Thischallengingperipancreaticmassbiopsywasunsuccessfulforthefirst2
passesbecausetheneedlekeptdeviatingmediallyfromitspredictedpath,likelyduetooverlyingfibroustissue.A,CTshows
mass(blackarrow)directlyinfrontofinferiorvenacava(‘‘IVC’’),posterolateraltoportalveinconfluence(‘‘PV’’),andbehindartery
(‘‘A’’)andcommonbileduct(‘‘CBD’’).Forthethirdattempt(ultrasoundshowninB),thetrajectory(dottedbiopsyguideline)was
placedoutsidethelesionbytheamountofpredicteddeviation,andtheneedletip(arrow)wassuccessfullyintroducedintothe
lesion.Pathologyreturnedunusualinflammatorypseudotumor.
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Ultrasound Quarterly Volume 24, Number1, March2008 Ultrasound-Guided Biopsies intheAbdomen andPelvis
FIGURE4. Useofahigh-frequencylineartransducertooptimizesmalllesionbiopsy.This5-year-oldwithahistoryofneuroblastoma
wasnotedtohavea4(cid:1)6mmnodule(arrow)intheleftlobeofhisliveratroutineCT(A).Thismasswasseenonlyonarterial-phase
images,precludingCT-guidedbiopsyeveniftheradiologistpreferredthatmodality.Notethatthelesion(arrow)iswellseen
(B)usinga12-MHzlinearultrasoundtransducer.Biopsy(C)(arrowdenotingneedletipinlesion)unfortunatelyreturned
metastaticneuroblastoma.
contributes toa highlevelof expertise and experience by the latter probes are often necessary for deep lesions that are
sonographers in the face of a constantly changing group of accessed between ribs, but should not generally be your first
residents and fellows, thereby enabling us to deliver more choice.Second,optimizeyourgray-scaleimage.Zoomin,put
uniform quality; the division of labor enables all participants your focal zones at the area of interest, and try harmonics;
to concentrate on a single task (sonographers on the probe we have found that compound imaging technology greatly
and guidance, and sonologists on passing the needle and improvesneedlevisualization.
managing the specimen); and the fact that the most difficult
and challenging biopsies require abdominal compression, Seeing the Needle
awkward transducer angulation, and/or prolonged targeting, Afterthegray-scaleimagehasbeenoptimized,whatcan
whichcanbenearlyimpossibletoperformbyasingleoperator. one do to help visualize the needle? Obviously, the more
perpendicularthesoundbeamistotheneedle,thestrongerthe
Image Optimization
reflection will be. Move the inner stylet in and out without
Thisisperhapsoneofthemostimportantaspectsofany actuallymovingtheouterneedle;thissavestissuetraumaand
nontrivial biopsy. First, choose the correct transducer. To
often is all that is needed to find the needle. Rotating the
quoteProfFayeLaing,Binultrasound,alwaysstarthigh,then needle often allows optimization of the specular ultrasound
golow.[Thatis,attempttousethehighestpossiblefrequency reflection from asymmetric needle tips. If these maneuvers
transducer. Many superficial liver lesions, especially those in
fail,thenjudiciouslymovingtheneedlebackandforthisoften
thelefthepaticlobe,canbeimagedwithhigh-frequencylinear
useful.Echogenicneedlecoatingsarenotacure-all,butdoaid
transducers (theBsmallparts[probes);thebetterdepictionof in needle detection32 with very little additional cost. Some
the target inherent with these transducers makes biopsies authorshavedescribedusingcolorDopplertolocateamoving
easier andenablesonetoreliablyhit smaller masses (Fig.4).
needle tip, but in our experience, the artifact associated with
If the lesion cannot be seen with a high-frequency linear
this generallylimitsits usefulness.
transducer,tryalower-frequencylinear(Bvascular[ probe)or
high-frequencycurvedlineararray.Ifthosedonotwork,move Patient Positioning
toalow-frequencycurvedlinearprobe,andonlyifallofthese Many practitioners inadvertently assume that biopsy
fail,usethesmallfootprintsector/vector/phaser probe.These should be performed with the patient in supine position,
FIGURE5. Theimportanceofpatient
positioning.This8-mmFNA-provenbreast
cancermetastasiswouldbedifficulttoaccess
fromananteriorapproachwiththepatientin
supineposition(thinwhitearrowinA),butwas
easilysampledintercostallywiththepatientin
leftlateraldecubitusposition(thickergrayarrow
inAdenotesultrasoundbiopsypath,whereas
BshowssonogramofFNA).
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Winteret al Ultrasound Quarterly Volume 24,Number 1, March2008
FIGURE6. Traditionalside-notchcoreneedle(A),newercylindricalfull-borecoreneedle(B),anddifferencesinpathological
specimenarea(C).
similar to the positioning used for most CT scans. Although Btouch-prep[ (the cytology team rolls the core on a glass
thisoftenworkswellforleftlobeliverandpancreaticbiopsies, slide and performs cytological analysis on the shed cells)
other targets are often more optimally accessed with the or, often with high accuracy, by simple visual inspection
patientinoblique,decubitus,orevenpronepositions(Fig.5). (Fig. 7). Interpretation of cytology specimens is not only
Spendtimescanningandpreparingaheadoftimewiththisin operator dependent but also inappropriate for some tumor
mind, and potentially difficult procedures can often be easily types, and thus, the decision to obtain cytological or
converted toverymanageableones. pathological specimen in a given patient should be individ-
ualized on a case-by-case basis; consult with your clinicians
Core Versus FNA
and pathology experts regarding the clinical question that
The choice between cytology (FNA) and pathology
needs to be answered and the best method for getting to
(core) is multifactorial and is often based on institutional that answer.
accessandexpertise.Ifcytologyserviceisnotavailableduring
the procedure to assess the adequacy of a specimen, a core Coaxial Versus Multiple Separate Passes
biopsy is often the best choice. The smaller needles possible Should one place a larger bore introducer needle and
with cytology (20- to 25-gauge) are associated with a
sample (either FNA or core biopsy) multiple times through
procedure that is likely safer aswell as more comfortable for
this, or should one serially perform multiple separate passes
the patient. In general, cytological aspiration should be with a smaller bore needle? As with many of the
considered in patients with a known malignancy and a high
Bcontroversies[ regarding technique in the biopsy arena,
pretest probability that the area on which a biopsy will be
there is a paucity of hard, evidence-based data regarding this
performed is a metastasis; hypervascular lesions; masses
question. Our general preference and practice is to perform
surrounded by certain structures (ie, bowel, blood vessels) multiple separate passes with a smaller bore needle. An
where trauma needs to be minimized; and epithelial tumors
exception is made when the initial needle placement is very
(adenocarcinomas and squamous cell carcinomas). Although
challenging; in these cases, we will place an introducer and
thereisagreatvarietyofopiniononthismatter,33ourcytology samplecoaxiallythrough it.
team believes that better FNA samples are obtained with the
smallestpossibleneedle(eg,25-gaugeforathyroidFNA)and
no suction, just vigorous back-and-forth motion to pack the
needle with cells. Larger needles and syringe suction give
fewer diagnostically adequate samples due to dilution with
bloodproducts14andarereservedfortherarescirrhouslesion
that fails to shed cells with the smallest gauge needle.
Interestingly, and perhaps somewhat counterintuitively, there
are very little data suggesting that appropriate use of an
18-gauge needle is any more dangerous than using a smaller
FNA needle.34
Biopsies are usually more appropriately performed
using automated cutting needles in cases other than those
just listed, particularly lymphoma, RCC, and hepatoma.
Although both work well, we generally prefer the newer
cylindrical full-bore cutting needles to the older side-notch
needles,becauseoneobtainssignificantlymoretissuepercore
for analysis than the former for a given puncture diameter
(Fig.6). If a small bowel loop needs to be traversed toget to
FIGURE7. CorebiopsyofHCCspecimenonTelfapadshows
the mass, try to use no larger than a 20-gauge needle. Core darkcirrhoticliver(mahoganycolorinreallife)ateitherend
biopsy specimens can be assessed for adequacy by either andpalewhitetumortissue(arrows)inthecenter.
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Ultrasound Quarterly Volume 24, Number1, March2008 Ultrasound-Guided Biopsies intheAbdomen andPelvis
FIGURE8. Hepaticbiopsythroughascites
issafe(seetext).Needles(arrows=tip)are
shownpassingthroughascites(‘‘A’’)into
hepaticmetastasesfromovariancancer
(A,firstpatient)andendometrial
carcinosarcoma(B,differentpatient).
One article suggested that the strategy of multiple 1 article that evaluated the use of a 17-gauge introducer with
separate needle passes might have a higher successful yield an 18-gauge biopsy needle in 128 patients with proven HCC
rate because slightly different areas of the target (due to the founda0%incidenceoftrackseedingwithameanfollow-up
inevitable slight differences in needle positioning inherent of410days36;however,8(6.25%)ofthesepatientsalsohadan
withthistechnique)aresampled,therebyavoidingrepeatedly episode of bleeding within 24 hours of biopsy that required
sampling a necrotic or nondiagnostic area.35 Another hospital admission, fluid resuscitation, and/or transfusion.
theoretical advantage to this technique is that if samples are This 6.25% bleed rate is significantly higher than the 0% to
performed during suspended respiration (as we always do), 1.4%ratespublishedinseveralotherseries,anditispossible
one does not shear or tear the capsule (liver, kidney, pleura, that this increasedrisk isrelated tothe coaxialtechnique.
peritoneum) but rather makes focal discrete punctures that
may have less tendency to bleed. Disadvantages to this Needle Technique
strategy include multiple holes in the covering capsule (as In choosing a needle path, consider the intervening
opposedtojust1holewithcoaxialtechnique)andthefactthat, structures (ie, attempt to avoid vasculature and bowel,
for very difficult and challenging biopsies, one has to although small bowel can generally be traversed safely with
successfully navigate theneedle tothe lesion multiple times. a20-to22-gaugeneedle),andusuallyselecttheshortestpath
The coaxial technique makes it easy to obtain multiple from skin to lesion. The needle should be advanced during
samples once the introducer needle is placed. There is suspended respiration with a firm, continuous motion to
generallyonly1holeinthecapsule.Normaltissueisrelatively minimize pain and to keep the needle on target. Also, the
protected from the trauma of multiple needle passages. needle tip is usually much easier to seewhen it is in motion.
Disadvantages of the coaxial technique include potential Slow and tenuous needle passes tend to deflect rather than
shearingofthecapsule(becausetheintroducerisgenerallyleft puncturestructures(likethelivercapsule),decreasetheability
induringquietrespirationbetweensamples),alargerpuncture toseetheneedletip,andincreasepatientpain,especiallywhen
holeinthecapsule,andrepetitivesamplingofthesamearea.A traversing the peritoneum or visceral structures sensitive to
postulated but unproven advantage is less chance for track stretching; thus, a brisk puncture is optimal when passing
seeding because the needle that samples the tumor is throughthese coverings.
withdrawn through the inside of the introducer needle. The Is biopsy through ascites safe? In a word, yes. Older,
issueofthetrueriskoftrackseedingisverycontroversial,but anecdotal teachings stated that biopsy through surrounding
FIGURE9. The‘‘Don’tLookAfterwards’’school.Gray-scale(A),colorDoppler(B),andpulsedDoppler(C,black-and-white
reproductionoforiginalcolorimage)imagesofajetofblood(arrow)flowingintosurroundingascitesfollowingrenaltransplant
(‘‘RTX’’)biopsy.Images15minuteslater(notshown)showasmallamountofblood,butthepatientdidfineandwasasymptomatic
theentiretime.
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Winteret al Ultrasound Quarterly Volume 24,Number 1, March2008
FIGURE10. AnexampleoftheDoppler‘‘patenttrack’’signimmediatelyafterliverbiopsy(seetext).A,Notebloodflowwithin
track(arrow)extendingtothelivercapsule(arrowheads).Thisflowwasabsentat5minutes(B,black-and-whitereproductionof
originalcolorimage),andthepatientremainedasymptomatic.Unfortunately,multiplelesionsvisibleinbothimagesrepresent
metastaticpancreaticadenocarcinoma.
fluid was a (relative) contraindication, presumably because vitalsignmonitoring;thisisaJointCommissiononAccredi-
there would be no tissue tamponade of the puncture site. tation of Healthcare Organizations requirement if moderate
However,severalstudies haveshownthat,atleastinthecase sedation has been administered. We do not obtain routine
oftheliver,thepresenceofascitesdoesnotaltercomplication postprocedure hematocrit/hemoglobin levels if the patient is
rates37,38 (Fig.8). asymptomatic. The patient must be awake, alert, and able to
hold down fluids before discharge.The patient should havea
Postprocedure ride home from the hospital, appropriate instructions about
Imaging what to do if questions or complications arise, and know the
protocol for contacting his or her physician to discuss the
There is no consensus as towhether one should image
biopsyresults.Goodcommunicationandpatientteachinghelp
afterabiopsytoassessfor potentialcomplications.TheBno[
prevent unfortunate outcomes such as the patient who had a
group feels that the patient should simply be assessed
liverbiopsy,returnedtohishome2hoursaway,hadmildpain,
clinically (Btreat the patient, not the lab test[ school of
and went to the local emergency room wherethe on-call sur-
thought), that most bleeds are small and resolve sponta-
geonheardthewordsBliverbiopsytoday[andthenperformed
neously,andthatimagingoftheseasymptomatichemorrhages
unnecessaryexploratoryceliotomyforasmallbleedthateasily
leads to unnecessary excitement and overtreatment (Fig. 9).
could havebeen managedconservatively.
Othersstatethatpostprocedureimagingisusefulinpredicting
high-risk groups for more careful follow-up. For example, a
SPECIFIC SITES
recent article by Kim et al39 showed that a negative Doppler
biopsy track immediately after biopsy had a 100% negative Liver
predictive value for postprocedural hemorrhage, whereas
The liver is likely the most commonly percutaneously
Doppler detectable flow in the track and again at 5 minutes
biopsiedsolidabdominalorgan.Liverbiopsiescanbedivided
later had a positive predictive value of 75% for postbiopsy
into Bmedical[ biopsies, acquiring tissue from a random site
bleeding(Fig.10).
in the hepatic parenchyma to assess for diffuse disease (eg,
staging hepatitis C damage, assessing cirrhosis, or grading
Monitoring rejection after transplant), versus Bsurgical[ biopsies, target-
Following an intra-abdominal biopsy, we observe the ing a specific suspicious lesion in the liver. The former has
patientfor~4hoursinadedicatedrecoveryareawithfrequent often been (and still often is) performed Bblindly[ with just
FIGURE11. Biopsycomplication.Severepain
afteranonradiology-performed‘‘blind’’liver
biopsy(noimageguidancewasused)
promptedapostprocedureCT.Scoutview(A)
denotesalargemassintherightabdomen
(blackarrows),showntobealargehematoma
(whitearrows)onaxialimaging(B).The
patientrequiredseveralbloodtransfusions
butrecovered.
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