**3.1. Percutaneous biopsy**

ing purulent echinococcus, as early as 1825 (Récamier) and 1833 (Stanley). Cytology was reported as a diagnosis method for liver disease by L. Lucatello (in Rome) in 1895, while F. Schupfer performed liver and spleen biopsies with a thicker needle twelve years later, in 1907. This new approach provided cylindrical-shaped tissue samples which could be

Other scarce accounts of successful procedures followed in the next couple of decades (Oli‐ vet, 1926; Huard 1935; Silverman, 1938; Baron, 1939; Kofler, 1940; Dible, 1943), using differ‐

A new stage in modern liver biopsy techniques was reached when, in 1957 and repeated in the following year, Menghini performed and reported on the first "one-second needle biop‐ sy" performed with a special small caliber needle with no trocar and a sharp bevel. This was the first time needle liver biopsy was introduced worldwide as a praised diagnostic techni‐ que capable of providing enough histological material for an accurate interpretation of the

Following this radical advancement, liver biopsy became more spread and the technique evolved once modern imagistic methods allowed for better and safer puncturing of the liver parenchyma. Thus, the technique entered the image-guided age of investigation per‐ formed under computed tomography (CT) or ultrasound (US) real-time screening. Re‐ ports from Denmark, China, the United Kingdom, France or the United States of America populated the 1960–1980 literature, once the technique became widespread and fully acknowledged by the academic community. Its utility in diagnosing liver diseases and later on in staging hepatitis or malignancies was undisputed for entire decades of

Recent advancements, based on the advent of new imagistic high-accuracy techniques based on both US and CT/RM approaches, highly diminished the role played by this invasive in‐ vestigation. The term "virtual biopsy" became more and more present in recent literature, once both doctors and patients alike became more confident and were introduced to these high-yield methods, such as Transient or Acoustic Radiation Force Elastography. Moreover, advanced serum markers (such as, for example, the Fibrotest-Actitest battery of tests) allow for an accurate non-invasive staging in hepatitis. The introduction of arterial uptake con‐ trast-enhanced US and CT/RM techniques substantially decreased the role of biopsy in diag‐

However, histology remains one of the most accurate methods for evaluating liver paren‐ chymal changes, and is always used in malignancies when the diagnosis is uncertain or when other non-invasive methods fail to provide an accurate staging for hepatitis. Along with these non-invasive techniques came a revolution in in-situ biopsy methods. Such is probe-based confocal laser endoscopy (pCLE), which uses miniaturized probes connected to a laser source through fiber optics, small enough to fit inside a biopsy needle, thus provid‐

ent aspiration techniques performed with different modified biopsy needles [1].

histologically prepared and analyzed [1].

86 Liver Biopsy – Indications, Procedures, Results

pathological changes present in the parenchyma [1].

the 20th century [1].

nosing liver biopsy [2–4].

ing rapid live assessment of liver architecture [5].

All modern percutaneous liver biopsy techniques have rapidity as a common denominator. Either cutting or suction needles can be used for transthoracic or subcostal biopsy, either af‐ ter palpation or imaging assessment of the puncturing zone, or, preferably, under continu‐ ous image guidance. The transthoracic approach is the preferred method used, under realtime US or (more rarely) CT guidance and after a thorough imaging investigation of the liver and puncture route. All percutaneous methods imply two phases, one extra-hepatic corresponding to the needle puncturing the skin and reaching the needle, and a hepatic stage in which the needle passes the liver capsule, collects the parenchyma material, and is swiftly extracted. It is considered a relatively safe procedure, complication rates varying be‐ tween studies, from 0.75% up to 13.6% [6].

Trucut needles and their modified versions driven by spring-loaded biopsy guns are in‐ creasingly used and are the instruments of choice in many centers worldwide, especially in Europe [7]. Needle diameters vary between 1.20 mm to 1.60 mm, smaller calibers being used when a high risk of complications is suspected.

Suction needles are less expensive and their operation allows for rapid intra-hepatic han‐ dling, thus being easier to use and possibly imply less bleeding-related complications. The most widespread types are the Menghini, Jamshidi and Klatskin needles, which remained virtually unchanged since their introduction in the second half of the last century. The maxi‐ mum required time for a complete syringe suction of the cytological material and the con‐ secutive needle retraction is 0.5 seconds. The intrahepatic phase is reduced to as low as 0.1 seconds when the needle is operated by an expert practitioner [8].

Image guidance has become mandatory in centers where the gastroenterologist can perform his or her own US exam. Real-time surveillance of the procedure greatly decreases the risk of complications (such as bleeding) and minimizes post-procedural complaints such as pain or hypotension. Hepatologists in the United States usually prefer to have a radiologist per‐ forming the procedure under CT or US guidance [8].

#### **3.2. Transjugular (transvenous) biopsy**

The transjugular route is preferred when the risk for complications is high and therefore a percutaneous approach is not considered safe enough for the patient. Patients with clinical ascites, known hemostatic defect, cirrhotic liver with clinical signs of organ deficiency (smaller size and increased palpatory stiffness) or morbid obesity are usually prime candi‐ dates for this approach. Another situation when the transvenous approach is preferred is when additional pressure measurements in the hepatic vein are required [8].

The resources needed for this procedure are higher than percutaneous approaches; howev‐ er, complication rates are lower (2.5% up to 6.5%) according to some authors [9], with mor‐ tality rates of approximately 0.09% in high-risk patient groups [10]. The expertise of the performing physician also plays a crucial role in the success rate of this procedure, and should be considered along with the higher resource costs when choosing this access route for a lower-risk patient [1].

**3.4. Adequacy of liver biopsy samples**

ing to approximately 20% sampling errors [15, 16].

subsequent grading and staging [1, 19, 20].

RNA detection etc.) [1].

Analysis of the biopsy material under ultraviolet fluorescent light may be required in order to identify porphyria. Liver tissue obtained through biopsy is then quickly transferred into a buffer solution, usually 4% or 10% neutral formalin, to avoid the alterations it may sustain due to hepatic enzymes autolysis. It can then be subjected to various preparation techniques, in accordance to what diagnostic tests will follow with that specific sample (frozen section,

Risks and Benefits of Liver Biopsy in Focal Liver Disease

http://dx.doi.org/10.5772/52620

89

An adequate biopsy fragment is between 1 and 4 cm long, weighting between 10 to 50 mg, with a minimal diameter of 1 mm. Fragmented samples from Menghini needles are accepta‐ ble, as their added size is somewhere in the vicinity of 2 cm (usually range from 1 to 2.5 cm in length). In order to properly represent the parenchymal architecture, at least 10–11 portal tracts should be completely present, six being a minimally acceptable number. Specimens of inadequate lengths usually lead to understaging of fibrosis and underestimate the grade of inflammation. Cirrhotic parenchyma usually comes fragmented through biopsy, thus lead‐

As it is appreciated that a liver biopsy specimen represents 1/50 000 of the total organ mass, discussions regarding how representative it can be for diffuse lesions always existed in the literature [8, 17]. It is however appreciated that most diffuse (steatosis or inflammation etc.) or focal lesions (both malignant and benign), as well as structural lesions such as fibrosis can be visualized with a fairly high degree of accuracy, if the minimum amount of liver paren‐ chyma and the required number of portal spaces are present. It was however demonstrated that the size of the sample is directly correlated to an underestimation of inflammatory changes [18], this paradigm being extended to fibrotic changes and has a direct effect on the

Another issue highly debated in literature is the inter-observer variability; even with the wide usage of quantification scores for both inflammation and fibrosis such as the Knodell [21] scoring system and the revised Ishak version [22] or the METAVIR score [23]. All inter‐ pretations are subjected to the experience and training of the pathologist, which is an inde‐ pendent variable in itself, separated from the inherent sampling and procedural errors. A second opinion is always recommended, and two pathologists are usually present in most large referral centers. Collaboration between the pathologist and the clinician performing

The most important quantification parameters refer to its geometry and relationship be‐ tween the principal compartments – portal tracts and the elements of the arterial vascular system; the configuration adopted by hepatocyte plates; the sinusoids and the perisinusoi‐ dal compartment; the amount of connective tissue, fat and the number of ducts present, as well as other normal cellular infiltrates of lymphoid origin [8]. Regenerative nodular hyper‐ plasia or macronodular cirrhosis can be sometimes classified as normal parenchyma, and the inherent variations of normal inflammatory cellular infiltrate can be misleading for an

inexperienced pathologist when observing low grade inflammatory lesions [8, 27].

the liver biopsy is also preferred, as some studies indicated [24–26].

Another very important aspect is the lower quality of the tissue specimens collected through the transjugular approach. The tissue cylinders are thinner and more fragmented than those obtained through percutaneous biopsy, and usually represent only 1-2 cm of the liver paren‐ chyma, containing fewer portal fields [11].

#### **3.3. Surgical or laparoscopic biopsy: Novel approaches for liver biopsy**

This approach is preferred in patients with peritoneal involvement when an abdominal cancer is present, with associated ascites or peritoneal disease with ascites of suspected hepatic origin. Also, focal hepatic lesions can be targeted for biopsy through the laparo‐ scopic channel.

Biopsy can thus be performed with either normal needle systems, or by wedge resection. However, the later approach may overestimate the level of fibrosis, as the resection is per‐ formed too close to the fibrotic capsule that envelops the liver. The procedure is always con‐ ducted under general anesthesia and requires controlled pneumoperitoneum by infusion of nitrous oxide, always performed by trained physicians, allowing for a good control of bleed‐ ing and a minimum set of complications due to the large working area created. In direct comparison with percutaneous biopsy, the laparoscopic approach provides a higher level of accuracy as it allows the evaluation of the surrounding peritoneum [12]. The main complica‐ tions are related to the general anesthesia used for the procedure, the local abdominal and intra-peritoneal traumas associated, as well as the risk of bleeding, which is also present in the other types of biopsy.

Advancements to surgical techniques led to the development of the natural orifice translu‐ minal endoscopic surgery (NOTES), a new surgically-derived endoscopic technique that uses a transgastric or transanal route to facilitate the access to the abdominal cavity. One re‐ cent study presented a liver biopsy performed through a transgastric flexible endoscopic de‐ vice which permitted the inspection of the liver and surrounding intraperitoneal space. The technique can be applied to morbidly obese patients or to patients at high risk of complica‐ tions [13]. This approach remains however limited at the present time to a few highly select‐ ed patients, and is performed only by trained surgeons and gastroenterologists, at moderate to high costs and in selected centers.

Recent studies also focused on evaluating the liver capsule in cirrhotic patients through pCLE inserted through a laparoscopic channel, this being a promising field in the advance‐ ment of minimally invasive biopsy techniques [14]. Another study describes the use of pCLE in a routine minilaparoscopy setting, performed under conscious sedation. The authors could describe subsurface serial images in real time, allowing for an in vivo analysis of the liver parenchyma [5]. This approach may lead the way to targeted biopsy through live as‐ sessment of the liver parenchyma, as well as immediate morphological and dynamic evalua‐ tion of intrahepatic structures.

#### **3.4. Adequacy of liver biopsy samples**

performing physician also plays a crucial role in the success rate of this procedure, and should be considered along with the higher resource costs when choosing this access route

Another very important aspect is the lower quality of the tissue specimens collected through the transjugular approach. The tissue cylinders are thinner and more fragmented than those obtained through percutaneous biopsy, and usually represent only 1-2 cm of the liver paren‐

This approach is preferred in patients with peritoneal involvement when an abdominal cancer is present, with associated ascites or peritoneal disease with ascites of suspected hepatic origin. Also, focal hepatic lesions can be targeted for biopsy through the laparo‐

Biopsy can thus be performed with either normal needle systems, or by wedge resection. However, the later approach may overestimate the level of fibrosis, as the resection is per‐ formed too close to the fibrotic capsule that envelops the liver. The procedure is always con‐ ducted under general anesthesia and requires controlled pneumoperitoneum by infusion of nitrous oxide, always performed by trained physicians, allowing for a good control of bleed‐ ing and a minimum set of complications due to the large working area created. In direct comparison with percutaneous biopsy, the laparoscopic approach provides a higher level of accuracy as it allows the evaluation of the surrounding peritoneum [12]. The main complica‐ tions are related to the general anesthesia used for the procedure, the local abdominal and intra-peritoneal traumas associated, as well as the risk of bleeding, which is also present in

Advancements to surgical techniques led to the development of the natural orifice translu‐ minal endoscopic surgery (NOTES), a new surgically-derived endoscopic technique that uses a transgastric or transanal route to facilitate the access to the abdominal cavity. One re‐ cent study presented a liver biopsy performed through a transgastric flexible endoscopic de‐ vice which permitted the inspection of the liver and surrounding intraperitoneal space. The technique can be applied to morbidly obese patients or to patients at high risk of complica‐ tions [13]. This approach remains however limited at the present time to a few highly select‐ ed patients, and is performed only by trained surgeons and gastroenterologists, at moderate

Recent studies also focused on evaluating the liver capsule in cirrhotic patients through pCLE inserted through a laparoscopic channel, this being a promising field in the advance‐ ment of minimally invasive biopsy techniques [14]. Another study describes the use of pCLE in a routine minilaparoscopy setting, performed under conscious sedation. The authors could describe subsurface serial images in real time, allowing for an in vivo analysis of the liver parenchyma [5]. This approach may lead the way to targeted biopsy through live as‐ sessment of the liver parenchyma, as well as immediate morphological and dynamic evalua‐

**3.3. Surgical or laparoscopic biopsy: Novel approaches for liver biopsy**

for a lower-risk patient [1].

88 Liver Biopsy – Indications, Procedures, Results

scopic channel.

the other types of biopsy.

to high costs and in selected centers.

tion of intrahepatic structures.

chyma, containing fewer portal fields [11].

Analysis of the biopsy material under ultraviolet fluorescent light may be required in order to identify porphyria. Liver tissue obtained through biopsy is then quickly transferred into a buffer solution, usually 4% or 10% neutral formalin, to avoid the alterations it may sustain due to hepatic enzymes autolysis. It can then be subjected to various preparation techniques, in accordance to what diagnostic tests will follow with that specific sample (frozen section, RNA detection etc.) [1].

An adequate biopsy fragment is between 1 and 4 cm long, weighting between 10 to 50 mg, with a minimal diameter of 1 mm. Fragmented samples from Menghini needles are accepta‐ ble, as their added size is somewhere in the vicinity of 2 cm (usually range from 1 to 2.5 cm in length). In order to properly represent the parenchymal architecture, at least 10–11 portal tracts should be completely present, six being a minimally acceptable number. Specimens of inadequate lengths usually lead to understaging of fibrosis and underestimate the grade of inflammation. Cirrhotic parenchyma usually comes fragmented through biopsy, thus lead‐ ing to approximately 20% sampling errors [15, 16].

As it is appreciated that a liver biopsy specimen represents 1/50 000 of the total organ mass, discussions regarding how representative it can be for diffuse lesions always existed in the literature [8, 17]. It is however appreciated that most diffuse (steatosis or inflammation etc.) or focal lesions (both malignant and benign), as well as structural lesions such as fibrosis can be visualized with a fairly high degree of accuracy, if the minimum amount of liver paren‐ chyma and the required number of portal spaces are present. It was however demonstrated that the size of the sample is directly correlated to an underestimation of inflammatory changes [18], this paradigm being extended to fibrotic changes and has a direct effect on the subsequent grading and staging [1, 19, 20].

Another issue highly debated in literature is the inter-observer variability; even with the wide usage of quantification scores for both inflammation and fibrosis such as the Knodell [21] scoring system and the revised Ishak version [22] or the METAVIR score [23]. All inter‐ pretations are subjected to the experience and training of the pathologist, which is an inde‐ pendent variable in itself, separated from the inherent sampling and procedural errors. A second opinion is always recommended, and two pathologists are usually present in most large referral centers. Collaboration between the pathologist and the clinician performing the liver biopsy is also preferred, as some studies indicated [24–26].

The most important quantification parameters refer to its geometry and relationship be‐ tween the principal compartments – portal tracts and the elements of the arterial vascular system; the configuration adopted by hepatocyte plates; the sinusoids and the perisinusoi‐ dal compartment; the amount of connective tissue, fat and the number of ducts present, as well as other normal cellular infiltrates of lymphoid origin [8]. Regenerative nodular hyper‐ plasia or macronodular cirrhosis can be sometimes classified as normal parenchyma, and the inherent variations of normal inflammatory cellular infiltrate can be misleading for an inexperienced pathologist when observing low grade inflammatory lesions [8, 27].
