Multiple fine-needle biopsies using a coaxial technique: Efficacy and a comparison of three methods

Purpose Compare the success of three coaxial fineneedle biopsy techniques in obtaining multiple cytologic specimens of high quality.Methods For each of three different biopsy needle and technique combinations (aspiration: 22-gauge Chiba; capillary: 22-gauge Chiba; 22-gauge Autovac aspiration biopsy gun), 30 sites (15 liver, 15 kidney) were selected for coaxial fine-needle biopsy in cadaveric liver and kidneys. For each coaxial technique, three sequential biopsies were performed through an 18-gauge coaxial needle at each of multiple sites. The quality of the resultant 270 specimens was graded by a blinded cytopathologist using a previously published grading scheme.Results Using the coaxial technique, there was no significant dropoff in the cytologic specimen quality among the first, second, and third biopsies at a specific site, regardless of the order of the techniques/needles used. This was true for organs, the overall data, and for the individual five grading criteria. There was, however, a significant difference among the biopsy techniques themselves. Though there was no difference in the quality of cytopathologic specimen obtained with the Autovac aspiration gun and the aspiration technique with a 22-gauge Chiba needle, both were statistically better than the nonaspiration, capillary technique utilizing a 22-gauge needle (p = 0.0001).Conclusion The use of a coaxial technique with a fineneedle, 22-gauge biopsy offers unique advantages in obtaining a nearly unlimited amount of high-quality material for cytopathologic analysis. In this study, no dropoff was found in specimen quality with subsequent biopsies.     

Postmortem evaluation of four randomly selected automated biopsy devices for transthoracic lung biopsy

Purpose To evaluate four automated devices to achieve transthoracic lung biopsy.Methods Transthoracic lung biopsy specimens were obtained randomly from 21 human cadavers with unsuspicious lungs using Biopty (18- and 20-gauge), BIP (18 and 20-gauge), ASAP (18 gauge), and Autovac (18- and 20-gauge) devices. A total of 63 biopsies were carried out with each device and each needle diameter. The same devices and needles were then used randomly for biopsy of peripheral lung metastases. Specimens obtained during both parts of the study were analyzed for the area of tissue on the histologic section, adequacy of tissue for diagnosis, tissue preservation, and crush artifact. The examining pathologist was kept unaware of which procedure was used to obtain the specimens and the cadavers' clinical history.Results The Biopty 18-gauge device performed statistically better than any other of the evaluated systems for biopsy of normal lung parenchyma (p < 0.05). For biopsy of lung metastases, the differences between the devices and needle diameters were less, although the Biopty 18-gauge device performed better than the Autovac 18-gauge, BIP 18-gauge, and all 20-gauge devices for the area of tissue on the histologic section (p < 0.05). The results of the full-cut Autovac biopsy system were remarkable because of the large number of biopsies during which no tissue was obtained.Conclusion Automated biopsy devices can obtain high quality lung specimens sufficient for definite histopathologic diagnosis. However, additional clinical studies on the use of automated biopsy devices for lung biopsy are mandatory.     

Fine-needle aspiration biopsy for cytopathologic analysis: utility of syringe handles, automated guns, and the nonsuction method.

The performances of seven techniques and devices used with 22-gauge needles to obtain biopsy specimens for cytologic analysis were compared by means of single-blinded evaluation with an objective, previously published grading scheme. A total of 420 specimens were obtained from 10 fresh human cadavers (42 specimens per cadaver), including 30 hepatic, 20 renal, and 10 pancreatic specimens per technique or device. No statistical differences existed in the liver, kidney, or pancreas or in the combined data in the performance of the aspirator gun, syringe holders, vacuum needle, and end-cut gun versus the manual aspiration biopsy technique performed with a 22-gauge Chiba needle. However, nonaspiration, fine-needle capillary biopsy (FNCB) performed statistically significantly worse than any other technique or device in the kidney and pancreas and in comparison with the overall combined data. In the liver, no statistically significant difference existed in the overall performance of FNCB versus conventional aspiration biopsy, but the amount of cellular material obtained with FNCB was statistically significantly less.     

Sonographically guided fine-needle biopsy of thyroid nodules: the effects of nodule characteristics, sampling technique, and needle size on the adequacy of cytological material

AIM: To evaluate the effects of sonographic characteristics of thyroid nodules, the diameter of needle used for sampling, and sampling technique on obtaining sufficient cytological material (SCM). MATERIALS AND METHODS: We performed sonography-guided fine-needle biopsy (FNB) in 232 solid thyroid nodules. Size-, echogenicity, vascularity, and localization of all nodules were evaluated by Doppler sonography before the biopsy. Needles of size 20, 22, and 24 G were used for biopsy. The biopsy specimen was acquired using two different methods after localisation. In first method, the needle tip was advanced into the nodule in various positions using a to-and-fro motion whilst in the nodule, along with concurrent aspiration. In the second method, the needle was advanced vigorously using a to-and-fro motion within the nodule whilst being rotated on its axis (capillary-action technique). RESULTS: The mean nodule size was 2.1+/-1.3 cm (range 0.4-7.2 cm). SCM was acquired from 154 (66.4%) nodules by sonography-guided FNB. In 78 (33.6%) nodules, SCM could not be collected. There was no significant difference between nodules with different echogenicity and vascularity for SCM. Regarding the needle size, the lowest rate of SCM was obtained using 20 G needles (56.6%) and the highest rate of adequate material was obtained using 24 G needles (82.5%; p=0.001). The SCM rate was 76.9% with the capillary-action technique versus 49.4% with the aspiration technique (p<0.001). CONCLUSION: Selecting finer needles (24-25 G) for sonography-guided FNB of thyroid nodules and using the capillary-action technique decreased the rate of inadequate material in cytological examination.     

Ultrasound-guided transthoracic co-axial biopsy of thoracic mass lesions

PURPOSE: To compare the diagnostic yield of fine-needle aspiration biopsy (FNAB) and cutting needle biopsy in thoracic lesions. MATERIAL AND METHODs: Thirty patients with thoracic mass lesions were subjected to ultrasound-guided co-axial FNAB and cutting needle biopsy using 0.7 mm aspirating and 1.0-mm cutting needles, respectively. The diagnostic yield of the individual modalities was compared with the combined yield. RESULTS: A conclusive diagnosis was obtained in 76.6% (n=23) of patients by FNAB and in 66.6% (n=20) by cutting needle biopsy. The combined diagnostic yield of FNAB and cutting needle biopsy was 93.3% (n=28) with a significant statistical difference (p<0.03) as compared to cutting biopsy alone. Of the patients, 23.2% (n=7) had benign and 76.6% (n=23) malignant aetiologies. The diagnostic yield of FNAB versus cutting needle biopsy in benign lesions was 57.1% (n=4) and 100% (n=7), respectively. The diagnostic yield of FNAB versus cutting needle biopsy in malignant lesions was 82.6% (n=19) and 56.5%, (n=13). Two patients remained undiagnosed by either modality. There were no complications. CONCLUSION: FNAB and cutting needle biopsy are complementary to each other and attempts should be made to obtain small tissue cores in addition to routine cytologic specimens in diagnosing thoracic lesions, especially in benign pathologies. US provides a safe guidance modality for lesions abutting the chest wall.     

Percutaneous Biopsy of Osteoid Osteomas Prior to Percutaneous Treatment Using Two Different Biopsy Needles

Biopsy is usually performed as the first step in percutaneous treatment of osteoid osteomas prior to laser photocoagulation. At our institution, 117 patients with a presumed diagnosis of osteoid osteoma had a trephine biopsy before a percutaneous laser photocoagulation. Biopsies were made using two different types of needles. A Bonopty biopsy needle (14-gauge cannula, 16-gauge trephine needle; Radi Medical Systems, Uppsala, Sweden) was used in 65 patients, and a Laurane biopsy needle (11-gauge cannula, 12.5-gauge trephine needle; Laurane Medical, Saint-Arnoult, France) in 43 patients. Overall biopsy results were positive for osteoid osteoma in 83 (70.9%) of the 117 cases. The Laurane needle provided a significantly higher positive rate (81.4%) than the Bonopty needle (66.1%; p < 0.05). This difference was not due to the size of the nidus, which was similar in the two groups (p < 0.05) and may be an effect of differences in needle caliber (12.5 vs. 14 gauge) as well as differences in needle design. The rate of positive biopsy results obtained in the present series with the Laurane biopsy needle is, to our knowledge, the highest rate reported in series dealing with percutaneous radiofrequency ablation and laser photocoagulation of osteoid osteomas.     

Effect of suction on specimen size in fine-needle aspiration biopsy

High incidences of unsatisfactory specimens in fine-needle aspiration biopsy for cytology have been reported previously. Inappropriate aspiration techniques may account partly for this. In this study, the effect of suction on specimen size was studied in vitro using an automatic sampler. Bovine liver, testis, and pig's kidney were used as target tissues and biopsies were performed with 18-, 20- and 22-gauge needles. Specimen weight increased rapidly and linearly with suction force (P less than .001), regardless of the target tissue or needle diameter, when standard needle movement was applied. In the absence of needle movement, the suction force, rate of increase of suction, and duration of suction had no effect on the weight of the specimens. Needle movement alone, without suction, also produced meager specimens. Suction alone does not seem to tear fragments off target tissues. Nevertheless, in combination with needle movement, suction force plays an important role in the determination of specimen size.     

Comparison of fully automated and semi-automated biopsy needles for lung biopsy under CT fluoroscopic guidance

Objective

The aim of this study was to compare two different automated biopsy needles, a fully automated biopsy needle (Monopty; Bard, Covington, GA) and a semi-automated biopsy needle (Temno; Bauer Medical, Clearwater, FL), for lung biopsy.

Methods

50 consecutive percutaneous lung biopsies using the Monopty needle between June 2006 and January 2007 and 66 consecutive lung biopsies for 1 nodule in each session using the Temno needle between February 2007 and August 2008 were performed under CT fluoroscopic guidance followed by histopathological evaluation.

Results

In 42/50 lung biopsies performed with the Monopty needle and 54/66 lung biopsies performed with the Temno needle, the final diagnosis was confirmed by independent surgical pathological findings or clinical follow-up. Sufficient samples for histopathological evaluation were obtained in all 50 (100%) biopsies using the Monopty needle and in 55 (83.3%) of the 66 biopsies using the Temno needle (p<0.01). Accurate diagnosis was achieved in 41 (97.6%) of 42 biopsies using the Monopty needle and in 45 (83.3%) of 54 biopsies using the Temno needle (p=0.04). Biopsy-induced complications were pneumothorax, haemoptysis and haemothorax in 44.0%, 10.0% and 6.0% of biopsies, respectively, using the Monopty needle and in 48.3%, 8.3% and 3.3%, respectively, using the Temno needle.

Conclusion

There is a possibility that a fully automated biopsy needle such as the Monopty is more useful for CT scan-guided lung biopsy than semi-automated biopsy needles.CT scan-guided needle biopsy of lung nodules has become a well-established diagnostic technique [1]. Most CT scan-guided lung biopsies cited in earlier reports [2,3] were performed with fine-needle aspiration for cytology and were useful in differentiating malignant from benign lesions. In addition, a tissue-core biopsy using a cutting needle, which enables histopathological evaluation of the samples obtained [4], has been implemented to enhance diagnostic ability. Owing to the development of the automated cutting needle, tissue-core biopsy can now be performed more easily and higher quality core specimens can be obtained for histopathological analysis [5-11].There are two types of automated cutting needles: the fully automated biopsy needle and the semi-automated biopsy needle. Comparisons have been made of the use of these needles for autopsy [12] or breast tissue biopsy [13]. To our knowledge, no investigation has been carried out to compare these two types of automated cutting needles for lung biopsy. The aim of this study was to compare two different automated biopsy needles, a fully automated biopsy needle (Monopty; Bard, Covington, GA) and a semi-automated biopsy needle (Temno; Bauer Medical, Clearwater, FL), for use in CT scan-guided lung biopsy.     

Fine-needle aspiration biopsy of abdominal lesions: diagnostic yield for different needle tip configurations.

Four fine-needle aspiration biopsy needles with different tip configurations were used in 133 patients with abdominal lesions. The 20-gauge needles were used in random sequence by several physicians. The specimen from each of the 522 needle passes was evaluated by two cytopathologists for adequacy to render a diagnosis and for the presence of cell block material. The Franseen needle produced a 16% and 9% better yield for diagnostic material than did the cut biopsy and spinal needles (P less than .05), respectively. The Westcott needle was better than the cut biopsy needle by 13%, and the spinal needle produced an 11% better yield than did the cut biopsy needle. Differences did not exist in liver biopsies but were present in pancreatic biopsies. The spinal needle was the least successful in yielding cell block material. Use of the cut biopsy needle resulted in the largest proportion of inadequate specimens, except its yield in cell blocks in the liver was 25% higher than that of the Westcott needle. The authors conclude that not all unusual designs for 20-gauge needle tips render results superior to those of the simple spinal needle.     

Percutaneous lung aspiration biopsy: a comparison between two fine needles.

Fine needle lung aspiration biopsy is now a well established method of obtaining tissue for histopathological diagnosis. It is fast, simple and reliable, and has a very low complication rate. We report our experience using two fine needles, the Turner and the EZ-EM Cut-Biopsy needles, comparing their yield and complication rates. We found that both needles had comparable diagnostic yields (65% with the Turner, and 71% with the EZ-EM) and complication rates. We also found that in most cases, aspirates alone were sufficient for diagnosis, and that obtaining tissue cores with larger bore EZ-EM needles did not significantly influence the diagnostic outcome. We conclude that both the Turner and the EZ-EM needles are equally effective and safe in percutaneous lung aspiration biopsy. The least traumatic needle should be used except when the cytological diagnosis is nonspecific inflammatory cells or inadequate, in which case a repeat with a cutting needle is advised to obtain a core of tissue.     

CT-guided liver biopsy: an update

Computed tomography (CT)-guided liver biopsy has become an accepted part of the diagnostic evaluation of patients with benign and malignant hepatic disease The advantages of imaging guidance over blind percutaneous biopsy are now well established in the literature. Controversy continues to exist, however, over the safety and accuracy of the procedure, as well as over the proper choice of needle: large-caliber cutting needle versus small caliber aspiration needle. In 1984, our group reported the results in a preliminary set of 180 patients in whom CT-guided biopsy of focal liver lesions was performed. The study indicated that cutting-needle sampling could provide increased diagnostic accuracy over fine-needle aspiration in both benign and malignant hepatic disease without a significant increase in complications. This paper reports the results in a series of 179 new patients who underwent CT-guided liver biopsy using a variety of needles. Comparison is again made between fine-needle and cutting-needle biopsy with respect to diagnostic accuracy and safety. A detailed discussion of the proper choice of biopsy needle as well as of the causes of both biopsy failure and complications is provided.     

Orbital mass lesions: US-guided fine-needle aspiration biopsy--experience in 37 patients.

PURPOSE: To evaluate the safety and effectiveness of using ultrasonographic (US) guidance for performing fine-needle aspiration biopsies of orbital mass lesions. MATERIALS AND METHODS: Thirty-seven patients with mass lesions in the orbit underwent US-guided fine-needle aspiration biopsy. Computed tomographic scans were available in all patients. In 19 patients, the lesions were located in posterior orbit, whereas in 18 patients the lesions were located in (n = 3) or extended up to (n = 15) the anterior compartment. Fine-needle aspiration biopsy was performed with 22-25-gauge needles and use of the freehand technique. RESULTS: Needle biopsies were performed safely and easily, and real-time US monitoring of the needle position was used to avoid injury to the eyeball. No major complications were encountered. Diagnostic specimens were obtained in 29 (78%) of the 37 patients, and 19 benign and 10 malignant disease processes were diagnosed. In eight patients (22%), an appropriate diagnosis could not be made, as aspiration samples yielded insufficient tissue. CONCLUSION: US provides safe and effective guidance for performing fine-needle aspiration biopsy in orbital mass lesions and is especially useful in deep-seated nonpalpable retrobulbar lesions.     

Sonographically guided percutaneous biopsy of gastrointestinal tract lesions

OBJECTIVE. Our objective was to evaluate the role and safety of sonographically guided percutaneous biopsy in the diagnosis of digestive tract lesions when the lesions are not suitable to biopsy by endoscopy and safely reachable by sonography. MATERIALS AND METHODS. We performed 42 biopsies in 41 patients (age range, 14-81 years; mean age, 57.5 years). We performed biopsies with real-time sonographic guidance using graded compression, with a 3.5-5-MHz microconvex transducer. In 39 biopsies, core specimens were obtained with an 18-gauge automatic needle gun; fine-needle aspiration biopsy was obtained in 28 patients with a 22-gauge needle and in the other four patients with a 21-gauge needle. In the remaining three patients, a coaxial technique with 20- and 22-gauge needles for cytology was used. RESULTS. In 40 (95.2%) of 42 core biopsies performed, a specific diagnosis was obtained. A positive diagnosis was obtained in 16 (45.7%) of 35 fine-needle aspirations. The lesions were located from the pharynx to the sigmoid colon. Twenty-eight patients had malignant lesions, and 13 had benign lesions. Only one serious complication, bile peritonitis, was observed. CONCLUSION. Percutaneous biopsy with sonographic guidance can be used safely and efficiently to diagnose digestive tract lesions that can be visualized on sonography and are not accessible endoscopically.     

Combining fine-needle aspiration and core biopsy under CT fluoroscopy guidance: a better way to treat patients with lung nodules?

OBJECTIVE: The goal of our study was to evaluate the efficacy of the combined use of fine-needle aspiration and tissue core biopsy under real-time CT fluoroscopy guidance. SUBJECTS AND METHODS: One hundred thirty-eight percutaneous needle lung biopsy samples were obtained by two methods. The samples obtained by tissue fine-needle aspiration underwent cytologic evaluation, and those obtained by core biopsy using an automated cutting needle underwent histologic evaluation. The final diagnosis was confirmed by independent surgical pathologic findings, independent culture results, or clinical follow-up. RESULTS: Rates of adequate specimens obtained and of precise diagnosis by combined use of fine-needle aspiration and core biopsy were 97.1% (134/138) and 94.2% (130/138) evaluated lung lesions, respectively, whereas those rates were 84.8% (117/138) and 79.7% (110/138) by fine-needle aspiration alone and 91.3% (126/138) and 89.1% (123/138) by core biopsy alone, respectively. Precise diagnosis was achieved by the combined use of the techniques in 30 (93.8%) of 32 lesions ranging from 3 to 10 mm in diameter, 42 (93.3%) of 45 lesions ranging from 11 to 20 mm, 43 (93.5%) of 46 lesions ranging from 21 to 30 mm, and 100% of 15 lesions ranging from 31 to 100 mm. In 89 of 90 lesions shown to be malignant by CT-guided lung biopsy and 30 of 44 shown to be benign, specific cell types could be proven from specimens obtained by the combined use of the two different types of needle biopsy. CONCLUSION: The combined use of fine-needle aspiration and core biopsy improves the diagnostic ability of CT fluoroscopy-guided lung biopsy, even in small lesions.     

Percutaneous CT-Guided Biopsy of the Lung: Comparison Between Aspiration and Automated Cutting Needles Using a Coaxial Technique

Purpose: To compare the accuracy and complication rate of two different CT-guided transthoracic needle biopsy techniques: fine needle aspiration and an automated biopsy device. Methods: Two consecutive series of respectively 125 (group A) and 98 (group B) biopsies performed using 20–22 gauge coaxial fine needle aspiration (group A) and an automated 19.5 gauge coaxial biopsy device (group B) were compared in terms of their accuracy and complication rate. Results: Groups A and B included respectively 100 (80%) and 77 (79%) malignant lesions and 25 (20%) and 18 (21%) benign lesions. No significant difference was found between the two series concerning patients, lesions, and procedural variables. For a diagnosis of malignancy, a statistically significant difference in sensitivity was found (82.7% vs 97.4%) between results obtained with the automated biopsy device and fine needle aspiration respectively. For a diagnosis of malignancy, the false negative rate of the biopsy result was significantly higher (p <0.005) in group A (17%) than in group B (2.6%). For a specific diagnosis of benignity, no statistically significant difference was found between the two groups (44% vs 26%) but the automated biopsy device provided fewer indeterminate cases. There was no difference between the two groups concerning the pneumothorax rate, which was 20% in group A and 15% in group B, or the hemoptysis rate, which was 2.4% in group A and 4% in group B. Conclusion: For a diagnosis of malignancy when a cytopathologist is not available on-site, automated biopsy devices provide a lower rate of false negative results and a similar complication rate to fine needle aspiration.     

CT导引下骶骨病变穿刺活检

目的 探讨CT导引下对骶骨病变穿刺活检技术和应用价值.方法 在CT导引下对21例骶骨病变联合使用Ackermann骨钻针、切割式活检针和抽吸式活检针采集骨性标本和非骨性标本.结果穿刺成功率100%,除1例标本为含坏死组织和凝血块外,其余均获得病理结果,病理活检成功率95.2%.结论 CT导引下穿刺活检是对骶骨病变作出正确诊断的可靠方法,操作简便、安全,并发症少,为术前诊断提供重要的参考依据.正确合理使用操作方法可以提高穿刺的成功率和缩短穿刺时间.     

Transjugular liver biopsy in liver transplant patients using an 18-gauge automated core biopsy needle

Aim of this retrospective study is to evaluate accuracy and safety of transjugular liver biopsy using an 18-gauge automated core biopsy needle, in patients underwent liver transplantation. 183 consecutively transjugular liver biopsy were performed in 115 liver transplant patients. An 18-gauge automated core needle biopsy was used in all patients. Technical success was achieved in 182 procedures (99.5%). In one patient we were not able to obtain a liver sample. The mean number of passages was 1.43 (range 1–5). Mean number of fragments was 2 (range 1–12). Mean total length of the specimens was 1.7 cm (range 0.5–3.4 cm). The specimen was adequate for diagnosis in 172 (94.5%) cases and suboptimal or inadequate in 10 (4.5%). Suboptimal or inadequate samples were associated with higher number of passages (2.0 vs. 1.4, p < 0.012), higher number of fragments (4.3 vs. 1.9, p < 0.0001) and decreased total length of the specimens (0.99 vs. 1.73, p < 0.03). As only complication one patient (0.5%) had a large perihepatic hematoma requiring blood transfusion. In conclusion using an 18-gauge automated core needle biopsy, in most liver transplant recipients, an accurate diagnosis can be obtained with one or two passages. This is associated with a low risk of complications.     

Ultrasonically guided percutaneous fine needle aspiration biopsy of solid masses

Fine needle aspiration biopsy is a highly accurate cytologic technique in the differentiation of benign vs. malignant disease. After careful localization with the ultrasound beam, a 22 gauge 0.6 mm needle is used to obtain four to five cell samples. Seventy percutaneous fine needle aspiration biopsies were performed nodes, subcutaneous nodules, and other retroperitoneal masses. Ninety-three percent accuracy was obtained with no complications. Studies in four patients with carcinoma of the tail of the pancreas were falsely negative for malignant cells; all four patients had desmoplastic tumors. Complications of hemorrhage, tumor seeding, infection, fistula formation, and pain encountered with other methods and using larger bore needles have not been found with the fine needle technique. It is a safe, accurate method that can be performed as an out-patient procedure.     

The use of ultrasound-guided cutting-needle biopsy in paediatric neck masses

Objective: Neck masses are common in children. Although there is a low incidence of therapeutically significant pathology, biopsy is occasionally required for evaluation. Open biopsy or fine needle aspiration may be used to obtain tissue. Open biopsy provides material suitable for histological analysis but requires general anaesthesia. Cytological material obtained by fine needle aspiration is often inconclusive. A core of histological material may also be obtained by percutaneous cutting-needle biopsy, a recognised procedure at other anatomical sites, usually performed under local anaesthesia.? Materials and Methods: There are few accounts using cutting needles in adult neck masses and no previous paediatric series. We present our experience of ultrasound-guided core biopsies of neck masses in 15 children ranging in age from three months to 16 years.? Results: Thirteen biopsies were easily performed without sedation as an outpatient procedure under topical and injected local anaesthetic. In all fifteen cases the procedure was well tolerated and a tissue successfully obtained.? Conclusion: Ultrasound guided cutting needle biopsies of head and neck masses of children can be performed under local anaesthesia in the majority of cases. Received: 2 October 1998; Revision received: 6 July 1999; Accepted: 6 July 1999     

Operator experience versus specimen quality in 15 commonly used biopsy devices

Open hepatic and renal biopsies were performed in 15 healthy pygmy pigs by each of 15 different commonly used needles/automated biopsy devices (guns). These biopsies were performed by three radiologists, each with widely varying prior experience in the use of each device. These 15 biopsy needles/biopsy guns were divided into six categories and compared in a multivariate model to assess differences in radiologist performance based upon their prior experience. The performance of individual radiologists varied the most with the group of aspiration needles. Even an experienced radiologist who had previously performed 55 such biopsies performed statistically worse than another radiologist who had performed in excess of 200. The biopsy guns, as a group, also demonstrated significant variability between radiologists and their experience level. However, when considered alone, experience appeared less a factor with the Bard 18-gauge (1.20 mm) long-throw biopsy gun. Considerable experience-related variability was also encountered in the liver with the Vim Silverman needle and in the kidney with the vacuum needles. The 14 gauge (2.00 mm) Tru-Cut needle provided a high-quality specimen seemingly independent of operator experience. Regardless of the needle or device used, prior experience in their use appears most important in biopsies of softer, less fibrous, and more vascular tissue. Correspondence to: K. D. HopperPresented at the 1991 meeting of the European Congress of Radiology