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Objective: The purpose of this study was to determine retrospectively the frequency and causes of false-negative diagnoses of lesions evaluated with percutaneous stereotactic biopsy performed with vacuum-assisted probes with the patient prone on a biopsy table., Materials and Methods: The records of 1,152 women (median age, 55 years; range, 31-94 years) with 1,280 lesions consecutively biopsied with 14-gauge (n = 159) or 11-gauge (n = 1,121) vacuum probes were reviewed retrospectively. The histologic diagnoses were malignant (n = 489), high-risk (n = 117), and benign (n = 674) lesions. Benign lesions were evaluated with repeated biopsy (n = 46) or mammographic follow-up for 24 months or longer (n = 506) or less than 24 months (n = 57). In 65 cases (10% of all benign lesions), follow-up was not performed. Fisher's exact tests were used to correlate patient, mammographic, and biopsy variables with false-negative diagnoses., Results: Of 508 lesions with a final diagnosis of malignancy, the initial needle biopsy diagnosis was malignant (n = 489), high-risk (n = 14), or benign (n = 5) lesion. The five false-negative diagnoses were related to gauge of the biopsy probe and specimen radiographic findings regarding calcifications but were not related to lesion type. False-negative diagnoses were made in 4.4% (three of 68) of cases in which 14-gauge vacuum biopsy was performed and in 0.45% (two of 440) of cases in which 11-gauge vacuum biopsy was performed (p = 0.019). False-negative diagnoses were made in 25% (one of four) of cases in which specimen radiographs showed no calcifications and 0.67% (two of 300) of cases in which they did show calcifications (p = 0.0390). False-negative diagnoses were made in 1.2% (three of 248) of cases of calcification lesions and 0.8% (two of 260) of cases of mass lesions (p = 0.679)., Conclusion: False-negative findings at stereotactic biopsy were least common with 11-gauge probes and were similar in frequency for calcifications and masses.

Objective: The purpose of our study was to better define the rate and variables associated with cancer underestimation when lobular neoplasia is found at minimally invasive breast biopsy., Materials and Methods: The records of 32,420 patients who underwent imaging-guided needle biopsy of the breast for mammographic or sonographic abnormalities from 1988 to 2000 were retrospectively reviewed. The 278 cases in which lobular neoplasia was the highest-risk lesion at biopsy were included. Of the 278 cases, 164 proceeded to surgical excision, allowing calculation of rates of underestimation from minimally invasive biopsy., Results: Of the 32,420 minimally invasive breast biopsies, lobular neoplasia was found in 278 (0.9%). One hundred sixty-four of the 278 (59%) continued to surgical excision, where cancer was pathologically confirmed in 38 (23%). No difference was seen in the underestimation rates for lesions diagnosed as lobular carcinoma in situ (25%, 17 of 67 lesions) versus atypical lobular hyperplasia (22%, 21 of 97 lesions). Statistically significant underestimation of carcinoma was found with biopsy of masses (with or without associated microcalcifications) rather than calcifications only, a higher BI-RADS category (p < 0.0001), use of a core biopsy device rather than a vacuum device (p < 0.01), and obtaining fewer specimens (p < 0.0001)., Conclusion: Significant sampling error occurs regardless of the type of core biopsy device, number of specimens obtained, histologic-radiographic concordance, mammographic appearance, and complete excision of the lesion as determined by imaging. For this reason, all patients with lobular neoplasia at core or vacuum-assisted biopsy should undergo surgical excision until further differentiating criteria can be determined.

Purpose: To prospectively determine if estrogen receptor (ER)-negative human epidermal growth factor receptor type 2 (HER2)-positive and ER-negative HER2-negative breast cancers have distinguishing clinical and imaging features with use of retrospectively identified patients and tissue samples., Materials and Methods: This HIPAA-compliant study was institutional review board approved. Informed consent was obtained from living patients and waived for deceased patients. Mean patient age at diagnosis was 53 years (range, 31-84 years). Clinical history; histopathologic, mammographic, and breast sonographic findings; and HER2 status as determined with immunohistochemistry or fluorescent in situ hybridization were evaluated in 56 women with ER-negative breast cancer. Imaging appearances and clinicopathologic characteristics were correlated with tumor HER2 status. P < .05 indicated a significant difference., Results: Lesion margins on mammograms (P = .028) and sonograms (P = .023), calcifications on mammograms (P = .003), and clinical cancer stage at diagnosis (P = .029) were significantly associated with HER2 status. In contrast to ER-negative HER2-negative tumors, ER-negative HER2-positive tumors were more likely to have spiculated margins (56% vs 15%), be associated with calcifications (65% vs 21%), and be detected at a higher cancer stage (74% vs 57%)., Conclusion: Biologic diversity of cancers may manifest in imaging characteristics, and, conversely, studying the range of imaging features of cancers may help refine current molecular phenotypes., ((c) RSNA, 2008.)

Purpose: To retrospectively determine the frequency and causes of failure to retrieve microcalcifications in nonpalpable lesions, as judged on a radiograph of the specimen, and to determine outcome in patients with those lesions., Materials and Methods: Informed consent was obtained from each patient prior to biopsy. The institutional review board approved this HIPAA-compliant study and granted a waiver of informed consent. Retrospective review was performed of 1701 consecutive nonpalpable microcalcification lesions in 1511 women aged 29-92 years (median age, 54 years) who underwent percutaneous stereotactic biopsy on a prone biopsy table. Biopsy was successively performed with 14-gauge core, 14-gauge vacuum, and 11-gauge vacuum devices, with mild selection bias, and for each lesion, biopsy was performed with one device. Radiographs of the specimen were obtained to see whether microcalcifications were retrieved. Patient, mammographic, and biopsy variables were correlated with negative radiographs of the specimen. At repeat biopsy or mammographic follow-up, outcome was evaluated in patients with benign histologic results and negative radiographs of the specimen by using Fisher exact test P values., Results: Radiographs of the specimen were negative in 16% (30 of 182) of lesions at 14-gauge core biopsy, in 4% (four of 96) of lesions at 14-gauge vacuum biopsy, and in 1% (19 of 1423) of lesions at 11-gauge vacuum biopsy (P < .001). Substantial bleeding was a significant factor (P < .001) in failure to retrieve microcalcifications at only 11-gauge vacuum biopsy. Histologic results in 53 lesions with negative radiographs of the specimen were malignant (n = 6), indicated atypical hyperplasia (n = 6), or were benign (n = 41). Follow-up in patients with 40 benign lesions was performed with repeat biopsy (n = 17, with malignancy in three lesions) or mammography (n = 23) for 15-128 months (median, 70 months); one patient with one lesion was lost to follow-up., Conclusion: Failure to retrieve microcalcifications was least common with 11-gauge directional vacuum-assisted biopsy and occurred in 1% (19 of 1423) of lesions. Cancer was missed in 8% (three of 40) of benign lesions in patients who were followed up., ((c) RSNA, 2006.)

Fourier transform infrared (FT-IR) spectroscopy in a multiple internal reflection (MIR) geometry is integrated with silicon-based microreactors to allow detection of a wide range of chemical species while taking advantage of inexpensive batch fabrication techniques applicable to silicon substrates. The microreactors are fabricated in silicon and glass using standard microfabrication and selective etching techniques. The small ( approximately 1 cm side) reactor size provides access to nearly the full mid-IR frequency region with MIR-FT-IR, allowing us to probe both solution-phase and surface-bound chemical transformations. The wide applicability of this approach is demonstrated with two representative test cases: kinetics of acid-catalyzed ethyl acetate hydrolysis and amidization of surface-tethered amine groups.

Purpose: To determine whether number of specimens obtained at stereotactic 11-gauge vacuum-assisted breast biopsy with the patient prone influences diagnostic accuracy and to determine whether this number varies depending on mammographic appearance of lesions as masses or microcalcifications., Materials and Methods: Biopsy was prospectively performed in 100 patients (median age, 55 years; range, 31-81 years) with 100 lesions that were mammographically evident as masses (n = 50) and microcalcifications (n = 50) with standardized protocol to acquire 20 specimens per lesion in three 360 degrees probe rotations at one skin entry site. Specimens were histologically evaluated sequentially, and findings were compared with results of surgical excision or of mammographic follow-up for at least 24 months. Differences in diagnostic yield after each probe rotation and differences in diagnostic yield between masses and microcalcifications were determined with chi(2) test., Results: Up to 12 specimens harvested within two 360 degrees probe rotations were necessary to yield correct diagnosis in 96% of patients with masses and 92% of patients with microcalcifications. Diagnostic yield was not improved with more than 12 specimens for masses or microcalcifications. In two (4%) of 47 patients with lesions that were eventually diagnosed as cancer, results at stereotactic biopsy indicated they were benign. Underestimation of diagnosis of lesions as atypical ductal hyperplasia and ductal carcinoma in situ occurred in two (50%) of four and two (17%) of 12 lesions, respectively. With 20 specimens harvested during three probe rotations, there was no statistically significant difference in diagnostic yield between patients with masses and those with microcalcifications (P =.68)., Conclusion: At 11-gauge vacuum-assisted biopsy, highest diagnostic yield was achieved with 12 specimens per lesion, independent of mammographic appearance of the lesion. Even with standardized retrieval of 20 specimens per lesion, underestimation of disease still occurs., (Copyright RSNA, 2004)

Two women, aged 50 and 51 years, underwent stereotactic, 11-gauge vacuum-assisted biopsy from the cranial approach of small lesions in the upper outer quadrant of the right breast with removal of lesions that were detected with mammography. Postbiopsy mammograms showed the metal clip or marker at the biopsy sites in both patients. Histologic analysis of both lesions indicated atypical hyperplasia. Mammograms obtained prior to surgical excision showed caudal z-axis migration of the clip or marker to be 6.5 cm at 5 weeks and 4.5 cm at 10 weeks, respectively. By ignoring the clip or marker that had migrated to an inaccurate location and by using internal and external breast landmarks to guide presurgical excision needle localization, the biopsy sites were successfully excised in both patients., (Copyright RSNA, 2003)

Objective: The purpose of this retrospective study was to determine which mammographically detected lesions in need of imaging-guided biopsy could undergo prone, stereotactic biopsy., Materials and Methods: From July 1991 through June 2001, 1687 consecutive patients (age range, 29-94 years; median age, 58 years) with 1894 lesions were referred by clinicians in a multispecialty clinic. The patients underwent stereotactic, prone, histologic biopsy of 1851 lesions (98%) and needle-localized breast biopsy of 43 lesions (2%). We performed stereotactic biopsies successively with 14-gauge automated large-core devices and 14- or 11-gauge vacuum-assisted devices. We evaluated lesions by patient, breast, lesion, and procedural variables to determine why stereotactic biopsy was not performed., Results: Of 1851 lesions referred for stereotactic biopsy, biopsies were canceled in 42 lesions (2%) not considered suspicious enough to warrant biopsy. Of 1809 lesions in which stereotactic biopsy was considered to be warranted, stereotactic biopsy was canceled for technical reasons in 29 lesions (2%). Of 43 lesions referred for surgical biopsy, stereotactic biopsy was thought to be technically problematic in five (12%). Inability to accomplish a stereotactic biopsy in 34 (2%) of 1852 lesions needing a biopsy was due to proximity to the chest wall (n = 10, 29%), inadequate lesion visualization unrelated to lesion depth (n = 19, 56%), and patient factors (n = 5, 15%)., Conclusion: Stereotactic biopsy had a technical success rate of 98% (1780/1809) and was used for histologic diagnosis in 96% (1780/1852) of mammographically detected lesions. Inadequate lesion visualization accounted for 85% (29/34) of stereotactic biopsy failures.

Objective: . This study was conducted to evaluate the outcome of cases of radial scar diagnosed by percutaneous core needle biopsy., Materials and Methods: Of 198 nonpalpable lesions diagnosed with radial scars found at core needle biopsy, 157 lesions constituting the study group had undergone surgical excision (n = 102) or mammographic surveillance after biopsy for at least 24 months (median, 38 months; n = 55). Mammographic lesion type, lesion size, biopsy guidance method, biopsy device, number of specimens per lesion, and presence of atypical hyperplasia at percutaneous biopsy were retrospectively analyzed. Results were compared with histologic findings at surgery or mammographic findings during surveillance., Results: . Carcinoma was found at excision in 28% (8/29) of lesions with associated atypical hyperplasia at percutaneous biopsy and 4% (5/128) of lesions without associated atypia (p < 0.0001). In the latter group, carcinoma was found at excision in 3% (2/60) of masses, 8% (3/40) of architectural distortions, and 0% (0/28) of microcalcification lesions. Malignancy was missed in 9% (5/58) of lesions biopsied with a spring-loaded device and in 0% (0/70) of lesions biopsied with a directional vacuum-assisted device (p = 0.01); and in 8% (5/60) of lesions sampled with less than 12 specimens per lesion and 0% (0/68) sampled with 12 or more specimens (p = 0.015). Lesion type, maximal lesion diameter, and type of imaging guidance (stereotactic or sonographic) were not significant factors in determining the presence of malignancy., Conclusion: . Diagnosis of radial scar based on core needle biopsy is likely to be reliable when there is no associated atypical hyperplasia at percutaneous biopsy, when the biopsy includes at least 12 specimens, and when mammographic findings are reconciled with histologic findings. When the lesion diagnosed by core needle biopsy as radial scar does not meet these criteria, excisional biopsy is indicated.

Purpose: To determine if a subset of atypical ductal hyperplasia (ADH) lesions diagnosed at 11-gauge, directional, vacuum-assisted, prone, stereotactic biopsy fit the "probably benign" definition of a less than 2% chance of being carcinoma at subsequent surgical excision., Materials and Methods: Clinical, mammographic, and stereotactic biopsy features in 104 consecutive nonpalpable ADH lesions were correlated with the presence of carcinoma at lumpectomy. The results were analyzed with chi(2) statistic, with P <.05 indicative of significant difference., Results: Surgical excision revealed carcinoma in 22 (21%) of 104 ADH lesions. The lowest incidences of carcinoma (each P <.02) were 16% (15 of 92) in patients with no personal history of breast carcinoma, 13% (nine of 67) when maximum lesion diameter was less than 10 mm, and 8% (three of 36) when 100% of the mammographic lesion was removed at stereotactic biopsy., Conclusion: No clinical, mammographic, or biopsy features alone or in combination could be used to define a substantial subset of probably benign lesions with a less than 2% chance of carcinoma at lumpectomy., (Copyright RSNA, 2002)

Purpose: To describe our experience with stereotactic histologic biopsy in patients with breast implants., Materials and Methods: Thirty-one (1.3%) of 2,399 consecutive lesions on which stereotactic histologic biopsy was performed were in breasts containing implants. Biopsy difficulties were evaluated for lesions in breasts with and breasts without implants. Biopsy was performed on lesions in patients with implants prone on a dedicated table, with automated large-core (n = 13) or directional vacuum-assisted (n = 18) devices. Follow-up was surgical (11 of 11 malignancies and two of three high-risk lesions) and mammographic (one of three high-risk lesions and 17 of 17 benign lesions)., Results: There were no implant ruptures, hematomas requiring drainage, infections requiring treatment, false-negative findings, or histologic underestimations. Difficulties with stereotactic histologic biopsy were more prevalent in breasts with implants and included positioning problems in 10 (50%) of 20 lesions in breasts with subglandular implants and zero (0%) of 10 with subpectoral implants, lesions seen on only one view in four (13%) of 31 lesions, specimen radiographs negative for calcifications in two (10%) of 20 lesions, prominent bleeding in two (6%) of 31 lesions, and suboptimally small tissue samples in three (10%) of 31 lesions., Conclusion: Stereotactic histologic biopsy is safe in breasts with implants. Compared with that in breasts without implants, biopsy is often technically more difficult and may eventually prove less accurate.

Purpose: To measure the effect of biopsy device, probe size, mammographic lesion type, lesion size, and number of samples obtained per lesion on the ductal carcinoma in situ (DCIS) underestimation rate., Materials and Methods: Nonpalpable breast lesions at 16 institutions received a histologic diagnosis of DCIS after 14-gauge automated large-core biopsy in 373 lesions and after 14- or 11-gauge directional vacuum-assisted biopsy in 953 lesions. The presence of histopathologic invasive carcinoma was noted at subsequent surgical biopsy., Results: By performing the chi(2) test, independent significant DCIS underestimation rates by biopsy device were 20.4% (76 of 373) of lesions diagnosed at large-core biopsy and 11.2% (107 of 953) of lesions diagnosed at vacuum-assisted biopsy (P <.001); by lesion type, 24.3% (35 of 144) of masses and 12.5% (148 of 1,182) of microcalcifications (P <.001); and by number of specimens per lesion, 17.5% (88 of 502) with 10 or fewer specimens and 11.5% (92 of 799) with greater than 10 (P <.02). DCIS underestimations increased with lesion size., Conclusion: DCIS underestimations were 1.9 times more frequent with masses than with calcifications, 1.8 times more frequent with large-core biopsy than with vacuum-assisted biopsy, and 1.5 times more frequent with 10 or fewer specimens per lesion than with more than 10 specimens per lesion.

Microcalcifications discovered by mammography require careful analysis, occasionally leading to core biopsy to exclude associated breast cancer. We report unrecognized milk of calcium layering on small field of view prone digital stereotactic images. We illustrate important features on prone digital images attributed to milk of calcium which can exclude breast neoplasm, suggest this diagnosis, and prevent unnecessary biopsy.

We describe the analysis of heat flow in a type of tunable optical fiber grating that uses thin-film resistive heaters microfabricated on the surface of the fiber. The high rate of heat loss from these microstructures and the relatively low thermal diffusivity of the glass yield unusual thermal properties. Approximate one-dimensional analytical calculations capture important aspects of the thermal characteristics of these systems. Comparison with experimental results that we obtained from devices with established designs validates certain features of the computations. This modeling also establishes the suitability of integrated thin-film heaters for several new types of tunable fiber grating devices.

This paper describes a procedure for making topologically complex three-dimensional microfluidic channel systems in poly(dimethylsiloxane) (PDMS). This procedure is called the "membrane sandwich" method to suggest the structure of the final system: a thin membrane having channel structures molded on each face (and with connections between the faces) sandwiched between two thicker, flat slabs that provide structural support. Two "masters" are fabricated by rapid prototyping using two-level photolithography and replica molding. They are aligned face to face, under pressure, with PDMS prepolymer between them. The PDMS is cured thermally. The masters have complementary alignment tracks, so registration is straightforward. The resulting, thin PDMS membrane can be transferred and sealed to another membrane or slab of PDMS by a sequence of steps in which the two masters are removed one at a time; these steps take place without distortion of the features. This method can fabricate a membrane containing a channel that crosses over and under itself, but does not intersect itself and, therefore, can be fabricated in the form of any knot. It follows that this method can generate topologically complex microfluidic systems; this capability is demonstrated by the fabrication of a "basketweave" structure. By filling the channels and removing the membrane, complex microstructures can be made. Stacking and sealing more than one membrane allows even more complicated geometries than are possible in one membrane. A square coiled channel that surrounds, but does not connect to, a straight channel illustrates this type of complexity.

Objective: The purpose of our study was to evaluate how often a mammographic abnormality thought to be produced by the biopsy procedure was evident on the initial follow-up mammogram after percutaneous biopsy of impalpable histologically benign lesions. We compared three stereotactic percutaneous biopsy methods., Conclusion: A mammographic density seen well only in the projection parallel to the biopsy needle tract was evident in 2% (5/226) of the lesions for which 11-gauge directional vacuum-assisted biopsy was used, 0% (0/96) of the lesions for which 14-gauge directional vacuum-assisted biopsy was used, and 0% (0/422) of the lesions for which 14-gauge automated large-core biopsy was used. No mammographic abnormalities assessed as BI-RADS categories 3, 4, or 5 (according to the American College of Radiology's Breast Imaging Reporting and Data System) and thought to be produced by the biopsy procedure were evident after any of the biopsy methods.

Dual, independently addressable thin-film resistive heaters fabricated in a multilayer geometry on the surface of an optical fiber provide a new, flexible means for thermally tuning the properties of intracore gratings. In particular, control of the current that is applied to each of these heaters permits the chirp and the central wavelength of the grating to be adjusted independently. The designs and simple fabrication procedures for these types of device, the important physics of heat flow in them, and a tunable add-drop filter that demonstrates essential aspects of their operation are described.

Purpose: To determine the rate and causes of false-negative findings and histologic underestimates at stereotactic biopsy of nonpalpable breast lesions., Materials and Methods: Stereotactic, 14-gauge, automated, large-core needle biopsy (LCNB) was performed in 483 consecutive nonpalpable breast lesions. Excision was advised for the 143 carcinomas, 25 atypical ductal hyperplasia (ADH) lesions, and five radial scars. Mammographic follow-up was advised for the benign lesions without a repeat biopsy., Results: Of the 310 benign lesions, 259 underwent mammographic follow-up at 6-85 months (median, 55 months) without repeat biopsy, 48 underwent repeat biopsy and three were lost to follow-up. On the basis of the histologic diagnosis of carcinoma at surgical biopsy, diagnosis with LCNB was not correct (i.e., disease was underestimated at histologic examination) in 14 (58%) of 24 ADH lesions and two (40%) of five radial scars. Two (1.2%) of 161 lesions with a final diagnosis of carcinoma were benign at LCNB but malignant at repeat biopsy (i.e., false-negative findings at LCNB). Repeat biopsy was prompted by mammographic progression at 6 and 18 months after LCNB., Conclusion: The false-negative rate with LCNB was 1.2% in this study and 4.0% in the literature. The presence of carcinoma in ADH and radial scar lesions was often underestimated.

Objective: The purpose of our study was to evaluate how often histologically benign lesions were completely removed as shown by the initial mammogram after biopsy. We compared three percutaneous biopsy techniques., Materials and Methods: Retrospective review was performed on 1206 consecutive impalpable breast lesions having percutaneous stereotactic biopsies done on a prone biopsy table using 14-gauge automated large-core needles (n = 721); 14-gauge directional vacuum-assisted probes (n = 192); and 11-gauge directional vacuum-assisted probes (n = 293). Lesions that were histologically benign and that did not have subsequent surgical excision had mammographic follow-up. The 667 initial mammograms after biopsy (advised to be done at 6 or 12 months and accomplished at 1-53 months [median, 7 months] after biopsy) were reviewed to see if the lesions were no longer apparent., Results: The lesion was absent in 9% (40/422) of lesions for which 14-gauge large-core biopsy was used, 22% (21/95) of lesions for which 14-gauge vacuum-assisted biopsy was used, and 64% (96/150) of lesions for which 11-gauge vacuum-assisted biopsy was used (p < .0001). No mammographic pseudolesions were created by the biopsy. No clinically significant complications occurred., Conclusion: The lesion was more often completely removed with directional vacuum-assisted biopsy than with automated large-core biopsy and more often completely removed with 11-gauge probes than with 14-gauge probes.

Two concepts for use in the fabrication of three-dimensional (3D) microstructures with complex topologies are described. Both routes begin with a two-dimensional (2D) pattern and transform it into a 3D microstructure. The concepts are illustrated by use of soft lithographic techniques to transfer 2D patterns to cylindrical (pseudo-3D) substrates. Subsequent steps-application of uniaxial strain, connection of patterns on intersecting surfaces-transform these patterns into free-standing, 3D, noncylindrically symmetrical microstructures. Microelectrodeposition provides an additive method that strengthens thin metal designs produced by patterning, welds nonconnected structures, and enables the high-strain deformations required in one method to be carried out successfully.

This paper describes the fabrication of large (up to 45 cm(2)) arrays of microwells, with volumes as small as ∼3 fL/well and densities as high as 10(7) wells/cm(2). These arrays of microwells are formed by casting an elastomer, poly(dimethylsiloxane) (PDMS), against "masters" prepared by photolithography; arrays of microwells in other polymers can be formed by using a master consisting of posts in PDMS. A straightforward technique, discontinuous dewetting, allows wells to be filled rapidly (typically on the order of 10(4) wells/s) and uniformly with a wide range of liquids. Several rudimentary strategies for addressing microwells are investigated, including electroosmotic pumping and gaseous diffusion.

Background: Two complementary approaches to studying the cellular function of proteins involve alteration of function either by mutating protein-encoding genes or by binding a small molecule to the protein. A mutagen can generate millions of genetic mutations; correspondingly, split-pool synthesis can generate millions of unique ligands attached to individual beads. Genetic screening of mutations is relatively straightforward but, in contrast, split-pool synthesis presents a challenge to current methods of screening for compounds that alter protein function. The methods used to screen natural products are not feasible for large libraries composed of covalently immobilized compounds on synthesis beads. The sheer number of compounds synthesized by split-pool synthesis, and the small quantity of individual compound attached to each bead require assay miniaturization for efficient screening., Results: We present a miniaturized cell-based technique for the screening of ligands prepared by split-pool synthesis. Spatially defined droplets with uniform volumes of approximately 50-150 nanoliters (depending on well dimensions) are arrayed on plastic devices prepared using a combination of photolithography and polymer molding. Using this microtechnology, approximately 6,500 assays using either yeast cells or mammalian tissue culture can be performed within the dimensions of a standard 10 cm petri dish. We demonstrate that the biological effect of a small molecule prepared by split-pool synthesis can be detected in this format following its photorelease from a bead., Conclusions: The miniaturized format described here allows uniformly sized nanodroplets to be arrayed on plastic devices. The design is amenable to a large number of biological assays and the spatially arrayed format ensures uniform and controlled ligand concentrations and should facilitate automation of assays. The screening method presented here provides an efficient means of rapidly screening large numbers of ligands made by split-pool synthesis in both yeast and mammalian cells.

Purpose: To determine what factors are associated with unsuccessful needle-localized breast biopsy (NLBB)., Materials and Methods: Findings in 280 consecutive nonpalpable breast lesions in 262 women (age range, 27-87 years; mean age, 55 years) who underwent nonstereotactic, mammographically guided, standardized NLBB were retrospectively analyzed according to mammographic lesion type, lesion size, number of lesions per breast, needle type, proximity of needle to lesion, radiologist, specimen size, surgeon, and histologic findings., Results: Biopsy failed in seven (2.5%) of 280 lesions. Failures were related to lesion type, lesion size, number of lesions per breast, accuracy of needle placement, and volume of tissue removed. Removal of more than one tissue specimen converted failure to success in 14 (67%) of 21 initially missed lesions, all microcalcifications., Conclusion: Unsuccessful NLBB was more likely with two lesions per breast, small lesions, small specimens, and microcalcifications. Piercing such lesions with the localizing needle led to successful biopsy. Removal of more tissue was helpful with missed microcalcifications.

Purpose: To compare histologic findings of atypical ductal hyperplasia (ADH) at 14-gauge, directional, vacuum-assisted breast biopsy (hereafter, vacuum-assisted biopsy) and at 14-gauge, automated, large-core breast biopsy (hereafter, large-core biopsy) with findings at histologic examination after surgical biopsy., Materials and Methods: Nonpalpable breast lesions were diagnosed as ADH at histologic examination after vacuum-assisted biopsy in 88 lesions in seven institutions and after large-core biopsy in 55 previously reported lesions. Histologic findings at subsequent surgical biopsy were compared for the presence of carcinoma., Results: On the basis of histologic findings of carcinoma at surgical biopsy, the diagnosis of ADH was not correct in 26 (48%) of 54 lesions sampled at large-core biopsy and in 13 (18%) of 74 lesions sampled at vacuum-assisted biopsy (Fisher exact test, P < .0004). More tissue specimens were obtained at vacuum-assisted biopsy (mean, 15.8 specimens) than at large-core biopsy (mean, 9.7 specimens). Individual specimens were twice as large at vacuum-assisted biopsy (mean, 34 mg) as at large-core biopsy (mean, 17 mg) (previously reported)., Conclusion: ADH was diagnosed 2.7 times more reliably at vacuum-assisted biopsy than at large-core biopsy (with no increase in complications) with most of the improvement as a result of acquisition of more than 10 specimens per lesion, but carcinoma was sufficiently underestimated with both methods to necessitate surgical biopsy.

A photothermal detector consisting of a relief grating on the surface of an elastomer was fabricated and characterized. The detector has a sensitivity of the order of microwatts per square millimeter and has rise and fall times of the order of tens of seconds. Numerical and analytical modeling account for the behavior of the detector.

Microcontact printing (mu CP) has been used to produce patterned self-assembled monolayers (SAMs) with submicrometer features on curved substrates with radii of curvature as small as 25 micrometers. Wet-chemical etching that uses the patterned SAMs as resists transfers the patterns formed by mu CP into gold. At present, there is no comparable method for microfabrication on curved surfaces.

Purpose: To assess the reliability and reproducibility of automated large-core breast biopsy., Materials and Methods: A consortium of 20 institutions reported, in a standardized fashion, their core breast biopsy data. All biopsies were performed with "long-throw" (2.3-cm) automated core biopsy devices fitted with 14-gauge needles. Needle guidance was accomplished by means of either a dedicated, stereotaxic device, in which the patient lies in the prone position, or high-frequency electronically focused ultrasound equipment., Results: The data in 6,152 lesions were gathered. Clinical or surgical follow-up was available in 3,765 lesions; 1,363 of these lesions were subsequently surgically excised, and the core histologic study showed cancer in 910 lesions, mammary intraepithelial neoplasia in 173 lesions, and benign disease in 280 lesions. In these 280 lesions, there were 15 false-negative core biopsies., Conclusion: The data show that percutaneous large-core breast biopsy is a reproducible and reliable alternative to surgical biopsy.

Purpose: To determine whether histologic findings of cancer or atypical hyperplasia at large-core needle biopsy (LCNB) of nonpalpable breast lesions match histologic findings at excision., Materials and Methods: Stereotaxic LCNB was performed with an automated prone unit, biopsy gun, and 14-gauge cutting needles in 450 nonpalpable breast lesions. Lesions classified as carcinoma or atypical ductal hyperplasia (ADH) at histologic examination after LCNB were excised. A pathologist retrospectively compared core and excisional histologic findings., Results: Histologic comparison was performed in 116 of 135 carcinomas after LCNB. Histologic findings were concordant in 99 carcinomas. Partial discordance in 17 carcinomas led to an additional surgical procedure in one case. Histologic comparison was performed in 16 of 19 ADHs diagnosed with LCNB. Histologic findings were concordant in five and discordant in 11 ADHs., Conclusion: LCNB findings of carcinoma are accurate and allow definitive therapeutic surgery, including mastectomy. LCNB findings of ADH are inaccurate, and excisional biopsy is necessary.

Four hundred forty-seven needle biopsies of the lung were carried out on 348 patients in a nonhospital outpatient setting. There were no fatalities or serious complications. A reliable working diagnosis was obtained in 74% of patients (86% true positive for malignancy). Diagnostic thoracotomy was avoided in 31%, and the diagnostic interval was shortened in most. Impressive economic benefits resulted. Careful postbiopsy evaluation revealed pneumothorax in 41% of patients, with 10% requiring chest tube drainage, usually on an ambulatory basis. With management of the infrequent complications by the radiologist, outpatient needle biopsy of the lung can be safe, reliable, and highly cost effective.

There are currently four needle biopsy methods for obtaining tissue from patients with possible diffuse liver disease or cancer. These include percutaneous blind needle biopsy, a visually guided needle biopsy at laparoscopy, guided fine-needle biopsies with ultrasonography or computed tomography, and the transvenous liver biopsy. We and others have found the guided fine-needle biopsy technique to be safe, relatively cheap, and highly accurate in the diagnosis of liver cancer. Blind percutaneous biopsy should be reserved for patients with possible diffuse, noncancerous, liver disease. Guided biopsies at laparoscopy can be done if the other two methods fail to give a tissue diagnosis. The transvenous approach is useful in patients with a coagulation disorder.