**2.2 Percutaneous ultrasound guided**

Percutaneous ultrasound guided biopsy is the standard of care [7]. This technique can be performed blind after localizing the kidney with an ultrasound probe, or performed with real-time ultrasound guidance. The patient is placed in a prone position with a towel or pillow beneath the abdomen to ensure proper positioning and to stabilize the kidney. The lower pole of the

kidney is localized using the ultrasound probe placed around the renal angle posteriorly (**Figure 2**). The area of skin overlying the lower pole can be marked and the probe removed (blind) or the probe is used to guide the biopsy needle throughout the procedure (real-time). From this point on the procedure is similar to the blind technique.

The use of ultrasound guidance is now universally available in most countries globally, except for some centres in low and low-middle income countries where the ultrasound machine may not be available in the centre or to the nephrologist. The implication of this is that nephrologists in such centres may not have the skill required and this contributes to declining practice of renal biopsy in many of such centres.

### **2.3 CT guided percutaneous**

CT guided PRB may be the primary imaging technique or is indicated in obese patients, patients with complex kidney anatomy (e.g. vascular anomaly, horse-shoe kidney), focal lesions, those in whom kidneys are not well visualized on ultrasound and in patients who have difficulty lying prone [7, 8]. Interventional nephrologists or radiologists perform this procedure in the CT suite. Patients are usually fasted for 8 hours to allow for administration of conscious sedation. An intravenous line is secured for fluid administration and monitoring equipment for vital signs and pulse oximetry are attached to patient [9]. Patient with difficulties lying prone are placed in the ipsilateral side-up position, however the location of a focal lesion also influences the position chosen, e.g. lesions along the lateral edge of the kidney may be difficult to access with an ipsilateral side-up approach [9].

After adequately positioning the patient, a localizing grid is placed and preliminary CT images at 5 mm axial slices covering the entire length of the kidney is obtained. Thereafter, the shortest and safe route is chosen, the skin overlying kidney is prepped, draped and anaesthetized with 1% lidocaine. A coaxial needle is advanced to the kidney with CT guidance and core biopsy samples or fine needle aspirates are collected [9]. Once all samples are collected the needle is removed and post-care is given, including a post-procedure imaging to exclude haemorrhage.

### **2.4 Transjugular renal biopsy**

Mal who intended to carry out a liver biopsy but accidentally also obtained renal tissue first performed this procedure in 1989 [10]. Thereafter he further explored the feasibility of the procedure and it has since been practiced with success. Transjugular renal biopsy (TJRB) is performed in a radiology suite by either an interventional nephrologist or radiologist with fluoroscopy guidance.

**17**

*\**

**Table 1.**

The aspiration needle or core biopsy approach may be used and the main differ-

Skill requirement + ++ +++ +++ ++ G. A No No Yes Yes No Cost + ++ +++ +++ ++

The right internal jugular vein is often preferred due to its straighter course to the inferior vena cava. Following injection of local anaesthetic to skin and subcutaneous area, the vein is punctured with an 18-guage needle just above the thyroid cartilage medial to the sternal head of the sternocleidomastoid [11]. A guide wire is inserted and then a venous sheath is introduced over it. Next the catheter is advanced under fluoroscopic guidance through the IVC into the right renal vein. Lastly, the TRJB needle, pre-filled with normal saline and attached to a 20 ml luer

ence between the two approaches is the biopsy instrument.

*Patient's refusal or uncooperative patients are universal contraindication to all approaches.*

*Renal Biopsy: Appraisal of the Methods DOI: http://dx.doi.org/10.5772/intechopen.86755*

Contraindications Hypertension

Obesity Small kidneys Bleeding diathesis Solitary kidney Infection Obstructed kidney

Bleeding Injury to structures Infections

Compelling indications

Routine admission required

Complications Pain

*Comparing the biopsy techniques.*

**US-guided biopsy**

None Obese

**CT guided biopsy**

Complex anatomy Focal lesions Poor USS visualization

History of allergic reaction to contrast

Tissue yield Good Excellent Excellent Excellent,

Pain Bleeding Injury to structures Infections Radiation contrast nephropathy

No No Yes Yes Yes

Obese Complex anatomy Bleeding diathesis Poor visualization Failed PRB Solitary kidney Cystic kidneys High kidney location

**Laporoscopic Open biopsy Transjugular** 

Obese Complex anatomy Bleeding diathesis Poor visualization Failed PRB Solitary kidney Cystic kidneys High kidney location

\* Religious

grounds

abundant

Surgical risks Surgical risks Capsular

**biopsy**

Morbidly obese Bleeding diathesis Liver + kidney biopsy

History of allergic reaction to contrast

Good

perforation Contrast nephropathy

**Figure 2.** *Percutaneous ultrasound guided renal biopsy.*

### *Renal Biopsy: Appraisal of the Methods DOI: http://dx.doi.org/10.5772/intechopen.86755*

*Renal Diseases*

similar to the blind technique.

**2.3 CT guided percutaneous**

**2.4 Transjugular renal biopsy**

*Percutaneous ultrasound guided renal biopsy.*

kidney is localized using the ultrasound probe placed around the renal angle posteriorly (**Figure 2**). The area of skin overlying the lower pole can be marked and the probe removed (blind) or the probe is used to guide the biopsy needle throughout the procedure (real-time). From this point on the procedure is

The use of ultrasound guidance is now universally available in most countries globally, except for some centres in low and low-middle income countries where the ultrasound machine may not be available in the centre or to the nephrologist. The implication of this is that nephrologists in such centres may not have the skill required and this contributes to declining practice of renal biopsy in many of such centres.

CT guided PRB may be the primary imaging technique or is indicated in obese patients, patients with complex kidney anatomy (e.g. vascular anomaly, horse-shoe kidney), focal lesions, those in whom kidneys are not well visualized on ultrasound and in patients who have difficulty lying prone [7, 8]. Interventional nephrologists or radiologists perform this procedure in the CT suite. Patients are usually fasted for 8 hours to allow for administration of conscious sedation. An intravenous line is secured for fluid administration and monitoring equipment for vital signs and pulse oximetry are attached to patient [9]. Patient with difficulties lying prone are placed in the ipsilateral side-up position, however the location of a focal lesion also influences the position chosen, e.g. lesions along the lateral edge of the kidney may

After adequately positioning the patient, a localizing grid is placed and preliminary CT images at 5 mm axial slices covering the entire length of the kidney is obtained. Thereafter, the shortest and safe route is chosen, the skin overlying kidney is prepped, draped and anaesthetized with 1% lidocaine. A coaxial needle is advanced to the kidney with CT guidance and core biopsy samples or fine needle aspirates are collected [9]. Once all samples are collected the needle is removed and post-care is given, including a post-procedure imaging to exclude haemorrhage.

Mal who intended to carry out a liver biopsy but accidentally also obtained renal tissue first performed this procedure in 1989 [10]. Thereafter he further explored the feasibility of the procedure and it has since been practiced with success. Transjugular renal biopsy (TJRB) is performed in a radiology suite by either an interventional nephrologist or radiologist with fluoroscopy guidance.

be difficult to access with an ipsilateral side-up approach [9].

**16**

**Figure 2.**


#### **Table 1.**

*Comparing the biopsy techniques.*

The aspiration needle or core biopsy approach may be used and the main difference between the two approaches is the biopsy instrument.

The right internal jugular vein is often preferred due to its straighter course to the inferior vena cava. Following injection of local anaesthetic to skin and subcutaneous area, the vein is punctured with an 18-guage needle just above the thyroid cartilage medial to the sternal head of the sternocleidomastoid [11]. A guide wire is inserted and then a venous sheath is introduced over it. Next the catheter is advanced under fluoroscopic guidance through the IVC into the right renal vein. Lastly, the TRJB needle, pre-filled with normal saline and attached to a 20 ml luer

lock syringe, is advanced down the catheter to obtain the tissue core (core biopsy technique) [11]. More than one pass is usually possible to improve tissue yield.

#### **2.5 Laparoscopic and open biopsy**

Laparoscopic biopsy is usually performed by a urologist mostly via the retroperitoneal approach but can be approached transperitoneally. The patient receives general anaesthesia, is placed in full right or left flank position, prepped and draped. Using a two-port technique, firstly the retroperitoneum is entered in the posterior axillary line, halfway between the ribs and iliac crest [12]. The lower pole of the kidney is then localized by blunt dissection with the laparoscopic lens to create a space posterior to the kidney. Next a 5 mm trochar is inserted under direct vision in the anterior axillary line at the level of the iliac crest to identify the kidney; the biopsy is taken using a laparoscopic biopsy forceps [12]. Multiple biopsies can be taken and thereafter haemostasis is secured. In uncertain cases, intraoperative ultrasonography can be performed via a laparoscopic probe, to confirm renal tissue before biopsy [12, 13].

Open biopsies can be performed in patients with contraindication to PRB, or during open abdominal surgeries for other renal indications, e.g. taking a biopsy during a partial nephrectomy. Some patients refuse open biopsies on religious grounds (Jehovah's witness refusing blood transfusion) [12], so the laparoscopic technique becomes the preferred option (**Table 1**).

## **3. Specimen handling and processing**

The manner in which the biopsy core collected is handled and processed contributes to the diagnostic and prognostic usefulness. The tissue core should be gently removed from the biopsy needle using an 18G needle, or washed from the needle onto a Petri dish, using a slow jet of normal saline. A magnifying lens or a dissecting microscope should be used immediately to confirm it is kidney tissue, and whether it is cortex or medulla. The renal cortex appears pale pink to tan with reddish blushes depicting the glomeruli, while the medulla usually contains straight red striations representing vasa recta [14].

The biopsy operator must be knowledgeable of effective ways of dividing the renal core obtained when needed, and the right fixative to use. This ensures that adequate samples are delivered to the pathologist, for the different processing and fixation methods required for light microscopy (LM), immunohistochemistry (IHC) and electron microscopy (EM). At least three cores are required, one each for LM, IHC and EM. The need for dividing tissue core arises if the number of cores obtained is inadequate, e.g. if only one core is obtained, 1 mm cuts are made from both ends for EM, while the remainder is cut in two, the larger of which is used for LM while the other for IHC [14]. Specimen should be placed quickly in appropriate fixatives and accompanied with adequate clinical information to guide the pathologist in interpreting the findings.

#### **3.1 Light microscopy**

The fixative for LM is buffered 10% aqueous formaldehyde solution. The tissue is examined using a light microscope which employs focused visible light to magnify objects viewed. Stains are used to enhance characterization of the tissue; common stains are H&E, periodic acid-Schiff (PAS), Silver, and Trichrome. Light microscopy (LM) shows predominantly proliferative lesions, and occasionally

**19**

future [15].

*Renal Biopsy: Appraisal of the Methods DOI: http://dx.doi.org/10.5772/intechopen.86755*

**3.2 Immunohistochemistry**

**3.3 Electron microscopy**

nephropathy may be missed without an EM.

overnight admission except severe complications arise.

**4. Appraisal of the methods**

membranous features and crescents. It gives limited magnification and so there is

This includes immunofluorescence (IF) and immunoperoxidase (IP). The choice of which to use often depends on the pathologist and resources available. Immunoperoxidase (IP) requires no special fixation, since a tissue pre-fixed in formalin for LM can be used for IP depending on the question to be answered. It produces well-developed antigen retrieval and results are reproducible [14]. Immunofluorescence is the choice of most renal pathologist. The fixation used is Zeus solution (modified Michel's tissue fixative). IF produces accurate location of deposits with the aid of dark field microscopes, and excellent resolution when fluorescence microscopes with epifluorescence attachments are used. Routine examinations during IF include immunoglobulin's (IgG, IgM, IgA), complements (C3, C1q, C4) fibrin, kappa and lambda chains. Other antibodies may be examined

depending on the question to be answered, e.g. C4d in allograft biopsies.

The fixative for EM is 2–3% glutaraldehyde or 1–4% paraformaldehyde. Electron

microscopy (EM) aids in visualizing the ultrastructure and cross section of the kidney tissue including the glomerular basement membrane, mesangium, capillary

Ideally all three histopathologic examinations discussed above should be performed on all individual patient's specimens received to avoid missed diagnosis. Diagnosis such as light chain-associated disease, IgA nephropathy, anti-glomerular basement membrane disease may be missed without IHC, while diagnosis such as minimal change disease, fibrillary glomerulopathy, immunotactoid glomerulopathy, dense deposit disease, Alports, and thin glomerular basement membrane

The image guided percutaneous techniques are successful in terms of tissue yield in majority of cases. Furthermore, image guidance is particularly instrumental to the safe performance of focus biopsies in cases of cystic kidneys and solid renal masses [9]. Apart from methods described earlier, newer imaging techniques, such as, CT fluoroscopy and fusion ultrasonography may apply to renal biopsy in the

Percutaneous ultrasound guided approach is standard care for biopsy of nonfocal lesions [7]. The real-time ultrasound guided technique has been compared to the blind technique after localisation with ultrasound, and no significant difference in tissue yield was noted [16]. Both techniques have similar potential complications and can be used in similar patients. The rates of complications associated with PRB are difficult to compare across studies because of the heterogeneity of studies in terms of technique and needle used, operator and definitions of complications, e.g. bleeding [7]. These procedures are however done routinely without need for

Tissue diagnosis may not be successful in about 6% of ultrasound guided biopsies in some series and common reasons are due to operator's technique, type/ size of biopsy needle, and patient factors (reduced GFR, small atrophic kidneys,

loops, tubulointerstitium, vessels. Immune deposits are also well visualized.

often a need for EM and or IHC to avoid missed diagnosis.

membranous features and crescents. It gives limited magnification and so there is often a need for EM and or IHC to avoid missed diagnosis.
