Free-hand, ultrasound-guided percutaneous renal biopsy: experience from a single operator

Complications of Percutaneous Kidney Allograft Biopsy: Systematic Review and Meta-analysis

BACKGROUND

Kidney biopsy is important to guide the management of allograft dysfunction but has a risk of complications. This review aimed to determine the incidence and risk factors of complications after kidney allograft biopsy.

METHODS

This is a systematic review and meta-analysis of randomized controlled trials, cohort studies, or case-control studies indexed on PubMed, Embase, Cochrane Central Register of Controlled Trials, World Health Organization International Clinical Trials Registry, and ClinicalTrials.gov, limited to the English language, from January 2000 to December 2020, including adult and pediatric kidney allograft biopsies. Primary outcomes were gross hematuria, bleeding requiring transfusion, and major complications (requiring interventions such as blood transfusion or surgical or radiological interventions).

RESULTS

The review included 72 studies (40 082 biopsies). The quality of included studies was suboptimal. Pooled rates of gross hematuria, bleeding requiring transfusion, and major complications were 3.18% [95% confidence interval (95% CI), 2.31-4.19], 0.31% (95% CI, 0.15-0.52) and 0.89% (95% CI, 0.61-1.22), respectively. Gross hematuria rates were lower in high-income compared with middle-income countries (2.59% versus 6.44%, P < 0.01) and biopsies performed by radiology as compared with nephrology departments (1.25% versus 3.71%, P < 0.01). Blood transfusion rates were lower in pediatrics than adults (0.0% versus 0.65%, P < 0.01). Major complications were lower in biopsies performed by specialists as compared with trainees (0.02% versus 3.64%, P < 0.01). Graft loss and mortality were extremely rare. Limitations included missing data, few randomized controlled trials, and possible publication bias.

CONCLUSIONS

The risk of complications after kidney allograft biopsy was low. Given the low quality of included studies, risk factors for complications should be further examined in future studies.

Ultrasound-guided percutaneous renal biopsy at a university hospital: retrospective analysis of success and complication rates

OBJECTIVE

To evaluate the success and complication rates of ultrasound-guided renal biopsy at a tertiary care hospital.

MATERIALS AND METHODS

This was a retrospective analysis of 97 ultrasound-guided renal biopsies, all performed by the same radiologist, between 1 March, 2017 and 31 October, 2019.

RESULTS

Of the 97 biopsies evaluated, 87 had a definitive pathological diagnosis. In five cases (5.4%), the biopsy results were inconclusive and a second procedure was required. In seven procedures (7.6%), there were complications, all of which were properly resolved.

CONCLUSION

Ultrasound-guided renal biopsy has proven to be a safe, effective method for the diagnosis of nephropathies, with high success rates.

Characterization of ferroptosis in kidney tubular cell death under diabetic conditions

Kidney tubular cell death induced by transforming growth factor-β1 (TGF-β1) is known to contribute to diabetic nephropathy, a major complication of diabetes. Caspase-3-dependent apoptosis and caspase-1-dependent pyroptosis are also involved in tubular cell death under diabetic conditions. Recently, ferroptosis, an atypical form of iron-dependent cell death, was reported to cause kidney disease, including acute kidney injury. Ferroptosis is primed by lipid peroxide accumulation through the cystine/glutamate antiporter system Xc- (xCT) and glutathione peroxidase 4 (GPX4)-dependent mechanisms. The aim of this study was to evaluate the role of ferroptosis in diabetes-induced tubular injury. TGF-β1-stimulated proximal tubular epithelial cells and diabetic mice models were used for in vitro and in vivo experiments, respectively. xCT and GPX4 expression, cell viability, glutathione concentration, and lipid peroxidation were quantified to indicate ferroptosis. The effect of ferroptosis inhibition was also assessed. In kidney biopsy samples from diabetic patients, xCT and GPX4 mRNA expression was decreased compared to nondiabetic samples. In TGF-β1-stimulated tubular cells, intracellular glutathione concentration was reduced and lipid peroxidation was enhanced, both of which are related to ferroptosis-related cell death. Ferrostatin-1 (Fer-1), a ferroptosis inhibitor, alleviated TGF-β1-induced ferroptosis. In diabetic mice, kidney mRNA and protein expressions of xCT and GPX4 were reduced compared to control. Kidney glutathione concentration was decreased, while lipid peroxidation was increased in these mice, and these changes were alleviated by Fer-1 treatment. Ferroptosis is involved in kidney tubular cell death under diabetic conditions. Ferroptosis inhibition could be a therapeutic option for diabetic nephropathy.

Fabrication and Characterization of a 20-MHz Microlinear Phased-Array Transducer for Intervention Guidance

This paper describes the design and fabrication of a miniature ultrasonic phased-array transducer used for intervention guidance. Currently, ultrasound probes are often placed at the body surface of the patients, leading to several drawbacks including the limitation of penetration and image quality. In order to improve the reliability of the guiding process, we propose a miniature phased-array transducer that can be placed adjacent to the intervention device during the interventional procedure. In this paper, we report the work that has been carried out on the development of this miniature phased-array transducer. It comprised 48 elements housed in a 3-mm-diameter needle. A specially designed flexible circuit was used for accommodating the transducer array in the long, thin needle housing. The center frequency and the fractional bandwidth were approximately 20 MHz and 42%, respectively, with an average crosstalk lower than -30 dB. The axial and azimuth resolutions were approximately 80 and [Formula: see text], respectively. The imaging capability of the transducer was further evaluated by acquiring the B-mode images of a needle in a cow liver. The performance of the proposed phased-array transducer demonstrates the feasibility of such an approach for interventional guidance.

Ultrasound-Guided Percutaneous Core Needle Biopsy of Abdominal Viscera: Tips to Ensure Safe and Effective Biopsy

Ultrasound-guided percutaneous core needle biopsy (USPCB) is used extensively in daily clinical practice for the pathologic confirmation of both focal and diffuse diseases of the abdominal viscera. As a guidance tool, US has a number of clear advantages over computerized tomography or magnetic resonance imaging: fewer false-negative biopsies, lack of ionizing radiation, portability, relatively short procedure time, real-time intra-procedural visualization of the biopsy needle, ability to guide the procedure in almost any anatomic plane, and relatively lower cost. Notably, USPCB is widely used to retrieve tissue specimens in cases of hepatic lesions. However, general radiologists, particularly beginners, find USPCB difficult to perform in abdominal organs other than the liver; indeed, a full understanding of the entire USPCB process and specific considerations for specific abdominal organs is necessary to safely obtain adequate specimens. In this review, we discuss some points and techniques that need to be borne in mind to increase the chances of successful USPCB. We believe that the tips and considerations presented in this review will help radiologists perform USPCB to successfully retrieve target tissue from different organs with minimal complications.

A novel approach to ultrasound-guided percutaneous native renal biopsy: a better tissue sampling technique

Background: Percutaneous renal biopsy (PRB) is an essential tool in diagnosis and management of various renal diseases. Conventional ultrasound-guided free-hand approaches to the lower pole of the kidney for PRB yield marginal tissue adequacy and causes a certain incidence of bleeding complications.

Objective: To describe a novel ultrasound-guided approach to the middle part of the kidney for PRB to obtain better tissue sampling.

Patients and methods: The plane angle between the renal biopsy needle and the skin was set at 30° for patients in the novel middle part approach group (n = 15) and 45° for patients in the conventional lower pole approach group (n = 15).

Results: The perpendicular distance between the needle tip and renal capsule in the middle part approach was significantly shorter than the lower pole approach group (0.92 ± 0.6 vs. 1.49 ± 0.4 cm, p = 0.005). The middle part approach to PRB yielded a significantly higher number of glomeruli (22.8 ± 7.2 vs. 15.3 ± 4.1, p = 0.002) and arcuate arteries (0.9 ± 0.6 vs. 0.5 ± 0.1, p = 0.02). The bleeding complications in the middle part approach seemed to be less than in the lower pole approach technique. Pain scores between the two methods as assessed using a visual analog scale were not different.

Conclusion: This novel approach to the middle part of the kidney for PRB provides comparable patient satisfaction and a superior adequacy of renal tissue when compared with the conventional lower pole approach with its consequent lower post biopsy bleeding complications. Larger studies to confirm this finding are warranted.

Retrospective Analysis of Ultrasound-Detected Bleeding Complications after Ultrasound-Guided Transcutaneous Kidney Biopsies

The aim of this retrospective single-center study was to examine ultrasound-detected complications after diagnostic parenchymal renal biopsies. After 471 ultrasound-guided kidney biopsies (225 native kidneys and 246 renal allografts), ultrasound revealed hematomas (21.9%), arterio-venous fistulas (8.9%), active bleeding (1.1%) and hematuria (0.4%). Only 0.8% of all patients required invasive intervention such as coiling (n = 3) and surgical procedures (n = 1). Three episodes of bleeding (0.6%) were solved with manual compression. One patient (0.2%) needed an irrigation catheter because of hematuria. Furthermore, six patients (1.3%) received blood transfusion. Ultrasound-guided biopsies are safe. With modern ultrasound machines using multi-frequency transducers with high resolution and harmonic imaging, even marginal bleeding after renal biopsy is detected.

The spectrum of renal cell carcinoma in adults

The spectrum of renal cell carcinoma (RCC) includes many neoplasms with distinct cytogenetics, biologic behaviors, and imaging appearances. The advent of molecular therapies targeting different tumor types, new insights into the relative roles of biopsy and surveillance for small incidental tumors, and a growing array of nephron-sparing interventions have altered management of RCC. Similarly, the role of the radiologist is changing, and it is becoming increasingly important for radiologists to familiarize themselves with the various types of RCC. This article introduces the reader to the common and uncommon recognized types of renal cell carcinoma and discusses how these neoplasms differ in imaging appearance and behavior.

Safety and tissue yield for percutaneous native kidney biopsy according to practitioner and ultrasound technique

Background

Although percutaneous renal biopsy remains an essential tool in the diagnosis and treatment of renal diseases, in recent times the traditional procedure of nephrologists has been performed by non-nephrologists rather than nephrologists at many institutions. The present study assessed the safety and adequacy of tissue yield during percutaneous renal biopsy according to practitioners and techniques based on ultrasound.

Methods

This study included 658 native renal biopsies performed from 2005 to 2010 at a single centre. The biopsies were performed by nephrologists or expert ultrasound radiologists using the ultrasound-marked blind or real-time ultrasound-guided techniques.

Results

A total of 271 ultrasound-marked blind biopsies were performed by nephrologists, 170 real-time ultrasound-guided biopsies were performed by nephrologists, and 217 real-time ultrasound-guided biopsies were performed by radiologists during the study period. No differences in post-biopsy complications such as haematoma, need for transfusion and intervention, gross haematuria, pain, or infection were observed among groups. Glomerular numbers of renal specimens from biopsies performed by nephrologists without reference to any technique were higher than those obtained from real-time ultrasound-guided biopsies performed by expert ultrasound radiologists.

Conclusions

Percutaneous renal biopsy performed by nephrologists was not inferior to that performed by expert ultrasound radiologists as related to specimen yield and post-biopsy complications.

Association of thrombotic microangiopathy and intimal hyperplasia with bleeding post-renal biopsy in antiphospholipid antibody-positive patients

OBJECTIVE

Renal biopsy remains the gold standard investigation for both diagnostic and prognostic purposes in the clinical management of lupus nephritis. However, it is not without potentially significant complications. The objectives of this study were to determine the rate of significant bleeding post-renal biopsy in patients with lupus nephritis and to identify risk factors associated with hemorrhagic complications.

METHODS

Clinical data were retrospectively collected on 215 renal biopsies performed over a 13-year period (1999-2012). Patients were categorized into 3 groups: a diagnosis of systemic lupus erythematosus (SLE) alone, SLE with coexisting antiphospholipid syndrome (APS), or a diagnosis of SLE with either positive anticardiolipin antibodies and/or lupus anticoagulant (LAC) without clinical APS manifestations.

RESULTS

Major bleeding complications were significantly more common in those with coexisting APS and/or antiphospholipid antibodies (aPL). LAC, presence of thrombotic microangiopathy (TMA) on renal biopsy, older age at the time of the biopsy (age >40 years), and elevated serum creatinine (>400 μmoles/liter) were independent risk factors for increased risk of bleeding. TMA and severe fibrous intimal hyperplasia on renal biopsy were significantly more prevalent in those who developed severe bleeding complications.

CONCLUSION

Based on these findings, lupus nephritis patients with coexisting APS, positive LAC, and histologic evidence of TMA and/or fibrous intimal hyperplasia are at increased risk of bleeding post-renal biopsy. aPL should be checked in all lupus nephritis patients before undergoing renal biopsy, as this subset of patients warrants particular caution pre- and postprocedure.

A modified technique for real time ultrasound guided pediatric percutaneous renal biopsy: the angled tangential approach

AIM

Pediatric renal biopsy may result in serious hemorrhagic complications, requiring additional diagnostic procedures, blood transfusion, vascular interventions, and prolongation of hospitalization. The aim of the present study was to propose the angled tangential approach technique for real-time ultrasound-guided pediatric percutaneous renal biopsy.

METHODS

A retrospective analysis of 166 percutaneous biopsies from June 2004 to May 2009 was performed. Patients' medical records, pathology results, and complications were reviewed.

RESULTS

No major complications were seen in the study group. The most frequently occurring minor complication was macroscopic hematuria, which occurred at the rate of 9.6%. Hematoma was detected in three cases and regressed spontaneously in all cases.

CONCLUSIONS

The angled tangential approach is a safe technique and an alternative option in pediatric percutaneous renal biopsies.

Nonfocal renal biopsies: adequacy and factors affecting a successful outcome

PURPOSE

The purpose of this study was to evaluate factors affecting the success of ultrasound-guided core biopsy of kidneys and determine the optimum number of passes.

METHODS

This retrospective study evaluated 484 nonfocal renal biopsies performed with 18-gauge side-notch biopsy needles. Number of biopsy passes, serum creatinine, body mass index, needle type, transplant age, kidney size, diabetic status, and operator were evaluated as predictors of the number of biopsy passes.

RESULTS

Four hundred seventy-four biopsies (338 transplant, 136 native) were included with mean number of passes 2.87 (3.1 native vs 2.78 transplant; P = 0.002). Mean number of glomeruli yielded per pass was 6.9 (7.2 transplant vs 6.1 native; P = 0.0002) with 3 passes adequate for histological diagnosis in 84% of biopsies. Native kidney, increasing serum creatinine level, trainee biopsy operator, and use of a Temno needle were found to be independent predictors of having more than 3 biopsy passes on multivariate analysis. Age, sex, body mass index, diabetic status, and kidney size were not associated with the number of biopsy passes.

CONCLUSIONS

The success of a nonfocal renal biopsy has many influencing variables, and in the absence of an on-site electron microscopy technologist to immediately evaluate biopsy samples, 3 passes with an 18-gauge needle would be adequate in 84% of kidneys to achieve a histological diagnosis, with 2 passes needed for transplant kidneys to meet the Banff 97 criteria.

The contemporary role of renal mass biopsy in the management of small renal tumors

The selective use of percutaneous biopsy for diagnosis in renal masses is a relatively uncommon approach when compared to the management of other solid neoplasms. With recent advancements in imaging techniques and their widespread use, the incidental discovery of asymptomatic, small renal masses (SRM) is on the rise and a substantial percentage of these SRM are benign. Recent advances in diagnostics have significantly improved accuracy rates of renal mass biopsy (RMB), making it a potentially powerful tool in the management of SRM. In this review, we will discuss the current management of SRM, problems with the traditional view of RMB, improvements in the diagnostic power of RMB, cost-effectiveness of RMB, and risks associated with RMB. RMB may offer important information enabling treating clinicians to better risk-stratify patients and ultimately provide a more personalized treatment approach for SRM.

Percutaneous renal biopsy of native kidneys: efficiency, safety and risk factors associated with major complications

INTRODUCTION

The use of an automated biopsy device and real-time ultrasound (current technology) for percutaneous renal biopsies (PRBs) has improved the likelihood of obtaining adequate tissue for diagnosis and has reduced the complications associated with renal biopsies. Our objective was to evaluate the efficacy and safety of the current PRB procedure and identify possible risk factors for the development of major complications.

MATERIAL AND METHODS

We collected all native kidney PRBs performed with current technology in our institute from January 1998 to April 2008. Studied variables were collected from the patient's chart at the time of the biopsy.

RESULTS

We analyzed 623 (96.4%) of 646 renal biopsies performed with the current automated procedure guided by real-time ultrasound. Although the effectiveness was 97.6%, there were 110 complications. Fourteen (2.24%) of these complications were major: 9 cases of renal hematoma, 2 cases with macroscopic hematuria (which needed blood transfusion), 1 case of intestinal perforation (which required exploratory laparotomy), 1 nephrectomy and 1 case of a dissecting hematoma. The logistic regression analysis demonstrated the following risk factors for developing major complications: diastolic blood pressure ≥ 90 mmHg, RR 7.6 (95% CI 1.35-43); platelet count ≤ 120×10(3)/µl; RR 7.0 (95% CI 1.9-26.2); and blood urea nitrogen (BUN) ≥ 60 mg/dl, RR 9.27 (95% CI 2.8-30.7).

CONCLUSIONS

The observed efficacy and safety of the current technique in the present study were similar to observations in previous studies. Diastolic blood pressure ≥ 90 mmHg, platelets ≤ 120×10(3)/µl and BUN ≥ 60 mg/dl were independent risk factors for the development of major complications following PRB.

Renal mass sampling: an enlightened perspective

Renal mass sampling (RMS) can be carried out by core biopsy or fine needle aspiration with each presenting potential advantages and limitations. The literature about RMS is confounded by a lack of standardized techniques, ambiguous terminology, imprecise definitions of accuracy, substantial rates of non-informative biopsies, and recurrent diagnostic challenges with respect to eosinophilic neoplasms. Despite these concerns, RMS has an expanding role in the evaluation and treatment of renal masses, in order to stratify biological aggressiveness and guide management that can range from surgery to active surveillance. Non-informative biopsies can be managed with surgical excision or repeat biopsy, with the latter showing encouraging results in recent studies. We propose a new classification in which all biopsies are categorized as non-informative versus informative, with the latter being subclassified as confirmed accurate, presumed accurate or confirmed inaccurate. This terminology will facilitate the comparison of results from various studies and stimulate progress. Incorporation of novel biomarkers and molecular fingerprinting into RMS protocols will likely allow for more rational management of patients with renal masses in the near future.

Clinicopathological Spectrum of Renal Biopsies in Children

BACKGROUND

Renal biopsy has revolutionized the study of glomerular diseases. A retrospective analysis of 104 consecutive renal biopsies performed in children at a tertiary care referral centre over five years is presented.

METHODS

All the biopsies were performed non-ultrasound guided by a single consultant nephrologist. Trucut needles were used in the initial few years and a Magnum biopsy gun (Bard) over subsequent three years. There were 66 boys and 38 girls.

RESULT

A male predominance occurred in the older and younger patients. The male: female ratio was 2.2:1, 1:1, and 2.7:1 for the age groups below five years, 5-10 years and above 10 years respectively. All patients tolerated the biopsy well and success rate was 94%. There were minimal complications in the form of post biopsy haematuria (33.3%). Haematuria was mild in most of the cases and settled down within 24 hours. None required transfusion. However, 60% patients had mild discomfort in the form of local pain. There was no mortality, infection or renal loss. The most common indication for a kidney biopsy was nephrotic syndrome. Out of 104 biopsies, 85 were in children with nephrotic syndrome. The commonest primary renal pathology was mesangial proliferative glomerulonephritis (38%), minimal change disease (19%), focal segmental glomerulosclerosis (15%) and membranoproliferative glomerulonephritis (7%).

CONCLUSION

Renal biopsy is a safe procedure in experienced hands and the commonest indication for a biopsy in children remains nephrotic syndrome.

Biopsy of renal masses: when and why

Percutaneous image-guided biopsy of renal masses is a safe and accurate procedure. Although once reserved for the diagnosis of unresectable renal cell carcinoma, metastases, lymphoma, and infection, today percutaneous image-guided biopsy has an expanded role. There is increasing awareness that a substantial proportion of small, solid renal masses are benign neoplasms. Although imaging can be used to diagnose most of them, some are incorrectly believed to represent renal cell carcinoma and unnecessary surgery may be performed. Based largely on advances in cytological techniques, percutaneous biopsy can be now be used to diagnose benign neoplasms and thus prevent them from being treated unnecessarily. Concurrent advances in percutaneous ablation have also promoted its use. As a result, there are 8 established indications for percutaneous biopsy, and reason to believe that the number of indications will expand further in the future.

The renal biopsy

CONTEXT

The first renal biopsy was carried out more than a century ago, but its widespread introduction into clinical use, beginning in the 1950s, helped develop nephrology into the powerful subspecialty of internal medicine that it is today. In the past 25 years, the use of the spring-loaded biopsy gun, in combination with newer visualization techniques, including ultrasound and computed axial tomography scanning, has led to greater tissue yield and to a much lower risk of complication. During this same time, our understanding of renal pathology has increased many fold. Correct fixation and processing of renal biopsy tissue is critical, and the laboratory must be skilled with renal biopsy light microscopy, immunohistochemistry, and transmission electron microscopy preparation.

OBJECTIVES

To provide an overview of the renal biopsy, including the techniques and its complications, and to summarize proper laboratory methods for processing renal biopsy tissue.

DATA SOURCES

This article is based on a review of the literature and on the experience of the author.

CONCLUSIONS

The experienced nephropathologist, knowledgeable in both renal medicine and pathology and thus able to correlate subtle tissue-derived information with appropriate clinical data, remains the most important key to the development of an accurate clinicopathologic diagnosis.

In vivo visualization of abdominal malignancies with acoustic radiation force elastography

The utility of acoustic radiation force impulse (ARFI) imaging for real-time visualization of abdominal malignancies was investigated. Nine patients presenting with suspicious masses in the liver (n = 7) or kidney (n = 2) underwent combined sonography/ARFI imaging. Images were acquired of a total of 12 tumors in the nine patients. In all cases, boundary definition in ARFI images was improved or equivalent to boundary definition in B-mode images. Displacement contrast in ARFI images was superior to echo contrast in B-mode images for each tumor. The mean contrast for suspected hepatocellular carcinomas (HCCs) in B-mode images was 2.9 dB (range: 1.5-4.2) versus 7.5 dB (range: 3.1-11.9) in ARFI images, with all HCCs appearing more compliant than regional cirrhotic liver parenchyma. The mean contrast for metastases in B-mode images was 3.1 dB (range: 1.2-5.2) versus 9.3 dB (range: 5.7-13.9) in ARFI images, with all masses appearing less compliant than regional non-cirrhotic liver parenchyma. ARFI image contrast (10.4 dB) was superior to B-mode contrast (0.9 dB) for a renal mass. To our knowledge, we present the first in vivo images of abdominal malignancies in humans acquired with the ARFI method or any other technique of imaging tissue elasticity.

Percutaneous renal biopsy: comparison of blind and real-time ultrasound-guided technique

The use of real-time ultrasound-guided renal biopsy is believed to be superior to blind biopsy, but there are few reports comparing the two techniques. The goal of the present study was to compare the outcomes of ultrasound-guided and blind renal biopsies at a single teaching institution, in terms of adequacy of tissue yield and frequency of hemorrhagic complications. We reviewed retrospectively the outcomes of all patients undergoing a percutaneous native kidney biopsy during a 2-year period (January 1, 2004 to December 31, 2005). Of 129 renal biopsies, 65 were ultrasound-guided and 64 were performed by the blind technique. All biopsies were performed by nephrology fellows under direct faculty supervision. The two patient groups were comparable in terms of age, sex, race, diabetes, hypertension, serum creatinine, and hematocrit. The mean number of glomeruli per biopsy was higher in the ultrasound-guided group than in the patients with a blind biopsy (18 +/- 9 versus 11 +/- 9, p = 0.0001). An inadequate tissue sample requiring repeat biopsy occurred in 0% of the ultrasound-guided biopsies and 16% of the blind biopsies (p = 0.0006). Large hematomas requiring vascular intervention or transfusion were less frequent in the ultrasound-guided biopsies (0% versus 11%, p = 0.006). The hematocrit 24 hours postbiopsy was higher in the ultrasound-guided biopsies when compared with the blind biopsies (32 +/- 5% versus 30 +/- 4%, p = 0.04). When compared with blind renal biopsy, real-time ultrasound-guided percutaneous renal biopsy provides a superior yield of kidney tissue and results in fewer hemorrhagic complications. Real-time ultrasound-guided renal biopsy is the preferred technique.

Ultrasound-guided biopsy of homogenous solid renal masses

OBJECTIVES

We evaluated the reliability of sonographic criteria in selecting solid renal masses for percutaneous fine-needle biopsy.

METHODS

In study 1 (intraoperative ultrasound study), we prospectively examined 100 consecutive patients scheduled for partial/radical nephrectomy by using two different high-resolution probes (Philips HDI 5000, CT8-4, L12-5; 4-12MHz). The main tumor was intraoperatively evaluated by B-mode and power Doppler sonography. Morphologic characteristics seen on ultrasound were categorized in (non-)homogenous and (non-)cystic renal masses and were related to findings of pathological examination. Study 1 provided the selection criteria for study 2. In study 2 (percutaneous biopsy study), under local anesthesia and with the use of an 18-G needle, we prospectively performed two to three sonographically guided percutaneous biopsies in 30 consecutive patients whose tumors appeared to be homogenous and noncystic according to the sonograph (convex array 3.5MHz, HDI 5000, C5-2 and Falcon 2101 EXL, B+K Medical).

RESULTS

In the ultrasound study, only 16 (22.9%) of the 76 clear-cell carcinomas but all 9 (100%) oncocytoma appeared homogenous and noncystic on high-resolution intraoperative ultrasound. By applying these results to 30 patients of study 2 (18 men, 12 women; aged 63+/-7.7 yr, tumor size 29+/-11.3mm) who met these sonographic criteria on preoperative transabdominal ultrasound, we bioptically diagnosed 8 (26.7%) benign tumors; 25 of 30 (83.3%) patients were accurately diagnosed. Small tumors (<3cm), decreased breathing compliance, and medially located renal lesions seem to negatively influence biopsy results.

CONCLUSIONS

Kidney tumors that appear noncystic and homogenous on preoperative ultrasound are more likely to be of benign origin. Ultrasound-guided percutaneous biopsy of these solid renal masses could determine renal tumor patients for whom surveillance might be an option. However, experienced and dedicated histopathologic evaluation remains crucial to observe patients with clearly benign biopsy results. All even slightly questionable biopsy findings require surgical exploration.

Renal Masses in the Adult Patient: The Role of Percutaneous Biopsy

Although percutaneous renal mass biopsy with cross-sectional imaging guidance has long been considered to be safe and accurate, there have been recent advances in imaging, interventional, and cytologic techniques that have increased the role of percutaneous biopsy in the diagnosis of renal masses. Today, biopsy plays a fundamental role in the care of patients with a renal mass. Biopsy results are used to confirm the diagnosis of renal cancers, metastases, and infections, and there is increasing evidence to suggest that biopsy can help subtype and grade many primary renal cancers. Because a considerable fraction of small solid renal masses are benign and do not need treatment, there is an increasing need to diagnose them. Biopsy after a full imaging work-up can help prevent unnecessary and potentially morbid surgical and ablation procedures in a substantial number of patients. Although more data are needed to understand the overall accuracy of biopsy for the diagnosis of benign lesions, many can be diagnosed with the aid of biopsy findings. This article reviews reported experience with percutaneous renal mass biopsy, discusses the technical factors that contribute to results, and details seven specific clinical settings that should prompt the clinician to consider percutaneous biopsy when encountering a renal mass.

Evaluation of imaging-guided fine-needle percutaneous biopsy of renal masses

To evaluate the utility of imaging-guided fine-needle percutaneous biopsy of renal masses, we conducted a prospective analysis of our imaging-guided procedures from January 1999 to February 2003. We performed 54 percutaneous core biopsies in 46 patients. Fluoro-computed tomography and ultrasound guidance were respectively used in 48 and six cases. One to four specimens were obtained by using an 18-gauge automated coaxial biopsy system. We reviewed the patients medical records, pathology results, and imaging studies. Core biopsy results were compared with surgical pathology (n=27) or clinical follow-up (n=19). All biopsies provided sufficient material for analysis. The mean tumor size was 33 mm. Biopsy findings were positive for malignancy in 31 cases; histologic diagnoses included renal cell carcinoma (n=23), transitional cell carcinoma (n=5), and metastasis (n=3). Biopsy revealed 15 benign diagnoses: oncocytoma (n=6), hemorrhagic renal cyst (n=3), chronic nephritis (n=3), angiomyolipoma (n=2), and mycotic renal abscess (n=1). The average follow-up period for patients with benign diagnoses was 16 months. Biopsy results showed normal renal parenchyma in eight of 54 procedures, all of which had recuperated by subsequent biopsies. No immediate complications occurred after the procedures. Imaging-guided percutaneous core biopsy is a safe and accurate method for the evaluation of renal masses.

Metastatic renal cell carcinoma: CT-guided immunotherapy as a technically feasible and safe approach to delivery of gene therapy for treatment

PURPOSE

To assess the technical feasibility and safety of weekly outpatient percutaneous computed tomographic (CT)-guided intratumoral injections of interleukin-2 (IL-2) plasmid DNA in a wide variety of superficial and deep tumor sites.

MATERIALS AND METHODS

Twenty-nine patients with metastatic renal cell carcinoma and a total of 30 lesions measuring 1.0 cm(2) or greater in accessible thoracic (n = 15) or abdominal (n = 15) locations underwent up to three cycles of six weekly intratumoral IL-2 plasmid DNA injections. CT was used to guide needle placement and injection. After injection cycle 1, patients whose tumors demonstrated stable (< or =25% increase and < or =50% decrease in product of lesion diameters) or decreased size (>50% decrease in product of lesion diameters) advanced to injection cycle 2. Patients whose lesions decreased in size by more than 50% over the course of injection cycle 2 were eligible to begin injection cycle 3. An acceptable safety and technical feasibility profile for this technique was deemed to be (a) a safety and feasibility profile similar to that of single-needle biopsy and (b) an absence of serious adverse events (as defined in Title 21 of the Code of Federal Regulations) and/or unacceptable toxicities (as graded according to the National Cancer Institute Common Toxicity Criteria).

RESULTS

A total of 284 intratumoral injections were performed, with a mean of 9.8 injections (range, 6-18 injections) received by each patient. Technical success (needle placement and injection of gene therapy agent) was achieved in all cases. Complications were experienced after 42 (14.8%) of the 284 injections. The most common complication was pneumothorax (at 32 [28.6%] of 112 intrathoracic injections), for which only one patient required catheter drainage. Complications occurred randomly throughout injection cycles and did not appear to increase as patients received more injections (P =.532). No patient experienced serious adverse events or unacceptable toxicities.

CONCLUSION

Percutaneous CT-guided intratumoral immunotherapy injections are technically feasible and can be safely performed.

Current status of kidney transplant: update 2003

Pediatric transplantation has seen remarkable advances over the past two decades with reduced morbidity and mortality, reduced rejection rates, and improved long-term patient and allograft survival. Infants currently have short-term patient and allograft survival rates better than any other age group; short-term allograft survival rates in CD recipients are equal to those in LD recipients. With decreased rejection, long-term allograft survival is improving dramatically. Transplantation allows for much reduced risks and improved metabolic status, growth and development, and more normal social interactions. The future of transplantation continues to be exciting, with opportunities for reduced immunosuppressive medications and their side effects, and the elusive goal of transplantation tolerance seems within reach.