Academic radiology: the real good news.
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Education, Medical↗
Biomedical subjects
L L Fajardo
Publications and source records attributed to L L Fajardo.
Stereotactic core-needle breast biopsy: a multi-institutional prospective trial.
PURPOSE: To assess the accuracy of stereotactic core-needle biopsy (CNB) of nonpalpable breast lesions within the context of clinically important parameters of anticipated tissue-sampling error and concordance with mammographic findings. MATERIALS AND METHODS: CNB was performed in 1,003 patients, with results validated at surgery or clinical and mammographic follow-up. Mammographic findings were scored according to the American College of Radiology Breast Imaging Reporting and Data System with a similar correlative scale for histopathologic samples obtained at either CNB or surgery. Agreement of CNB findings with surgical findings or evidence of no change during clinical and mammographic follow-up (median, 24 months) for benign lesions was used to determine results. Three forms of diagnostic discrimination measures (strict, working [strict conditioned by tissue sampling error], applied [working conditioned by concordance of imaging and CNB findings) were used to evaluate the correlation of CNB, surgical, and follow-up results. RESULTS: Strict, working, and applied sensitivities were 91% +/- 1.9; 92% +/- 1.8, and 98% +/- 0.9, respectively; strict, working, and applied specificities were 100%, 98% +/- 0.8, and 73% +/- 0.9; strict, working, and applied accuracies were 97%, 96%, and 79%. CONCLUSION: Percutaneous stereotactic CNB is an accurate method to establish a histopathologic diagnosis of nonpalpable breast lesions. Accuracy increases when additional surgery is performed for lesions with anticipated sampling error or when CNB findings are discordant with mammographic findings. An understanding of the interrelationship among these parameters is necessary to properly assess results.
Biopsy, Needle↗
Fine-needle aspiration biopsy of nonpalpable breast lesions in a multicenter clinical trial: results from the radiologic diagnostic oncology group V.
PURPOSE: To determine the diagnostic accuracy of ultrasonographically (US) and stereotactically guided fine-needle aspiration biopsy (FNAB) in the diagnosis of nonpalpable breast lesions. MATERIALS AND METHODS: At 18 institutions, 442 women who underwent 22-25-gauge imaging-guided FNAB were enrolled. Definitive surgical, core-needle biopsy, and/or follow-up information was available for 423 (95.7%) of these women. The reference standard was established from additional clinical and imaging information for an additional six (1.4%) women who did not undergo further histopathologic evaluation. The FNAB protocol was standardized at all institutions, and all specimens were reread by one of two expert cytopathologists. RESULTS: When insufficient samples were included in the analysis and classified as positive, the sensitivity and specificity of FNAB were 85%-88% and 55.6%-90.5%, respectively; accuracy ranged from 62.2% to 89.2%. The diagnostic accuracy of FNAB was significantly better for detection of masses than for detection of calcifications (67.3% vs. 53.8%, P =.006) and with US guidance than with stereotactic guidance (77.2% vs. 58.9%; P =.002). CONCLUSION: FNAB of nonpalpable breast lesions has limited value given the high insufficient sample rate and greater diagnostic accuracy of other interventions, including core-needle biopsy and needle-localized open surgical biopsy.
Biopsy, Needle↗
MRI-guided needle localization: technique.
Magnetic resonance imaging (MRI) is being used increasingly in breast cancer diagnosis. Such indications include the search for a breast primary in women with metastatic carcinoma in the axillary lymph nodes, improving surgical planning in women with a biopsy-proven breast cancer, and in screening very high-risk women. If a suspicious lesion is found by MRI, localization with either directed additional mammographic or sonographic views or with MRI-guided needle localization or biopsy is necessary. We describe the use of a biopsy device with embedded internal fiducial markers. The coordinates for needle placement are calculated by distances between the fiducial markers and the lesion. The technique is simple to master and is aided by the use of a practice phantom.
Aged↗
A localization algorithm and error analysis for stereo x-ray image guidance.
Stereo x-ray radiography attracts increasing attention in major clinical applications. The purpose of this paper is to analyze the 3D localization error for breast biopsy procedures and provide guidelines for improving its accuracy. Our prototype is a CCD based digital stereo x-ray imaging system. The mathematical model consists of two x-ray sources and one stationary detector plane. A closed form least-squares solution is derived for 3D localization of feature points, particularly a biopsy needle tip, from a pair of 2D digital radiographs. Based on the least-squares formula and its first order approximation, the 3D localization error is analyzed in terms of object location, measurement error, separation between the two x-ray sources, and distance from the source to the detector. The stereo imaging and error estimation formulas are numerically simulated and experimentally validated. The data are in agreement with theoretical prediction. These results can be used for the purpose of system design and protocol optimization.
Algorithms↗
Lens distortion in optically coupled digital x-ray imaging.
UNLABELLED: The objectives of this research are to analyze geometrical distortions introduced by relay lenses in optically coupled digital x-ray imaging systems and to introduce an algorithm to correct such distortions. METHODS: The radial and tangential errors introduced by a relay lens in digital x-ray imaging were experimentally measured, using a lens-coupled CCD (charge coupled device) prototype. An algorithm was introduced to correct these distortions. Based on an x-ray image of a standard calibration grid, the algorithm first identified the location of the optical axis, then corrected the radial and tangential distortions using polynomial transformation technique. RESULTS: Lens distortions were classified and both radial and tangential distortions introduced by lenses were corrected using polynomial transformation. For the specific lens-CCD prototype investigated, the mean positional error caused by the relay lens was reduced by the correction algorithm from about eight pixels (0.69 mm) to less than 1.8 pixels (0.15 mm). Our investigation also shows that the fourth order of polynomial for the correction algorithm provided the best correction result. CONCLUSIONS: Lens distortions should be considered in position-dependent, quantitative x-ray imaging and such distortions can be minimized in CCD x-ray imaging by appropriate algorithm, as demonstrated in this paper.
Algorithms↗
Radiologists' preferences for digital mammographic display. The International Digital Mammography Development Group.
PURPOSE: To determine the preferences of radiologists among eight different image processing algorithms applied to digital mammograms obtained for screening and diagnostic imaging tasks. MATERIALS AND METHODS: Twenty-eight images representing histologically proved masses or calcifications were obtained by using three clinically available digital mammographic units. Images were processed and printed on film by using manual intensity windowing, histogram-based intensity windowing, mixture model intensity windowing, peripheral equalization, multiscale image contrast amplification (MUSICA), contrast-limited adaptive histogram equalization, Trex processing, and unsharp masking. Twelve radiologists compared the processed digital images with screen-film mammograms obtained in the same patient for breast cancer screening and breast lesion diagnosis. RESULTS: For the screening task, screen-film mammograms were preferred to all digital presentations, but the acceptability of images processed with Trex and MUSICA algorithms were not significantly different. All printed digital images were preferred to screen-film radiographs in the diagnosis of masses; mammograms processed with unsharp masking were significantly preferred. For the diagnosis of calcifications, no processed digital mammogram was preferred to screen-film mammograms. CONCLUSION: When digital mammograms were preferred to screen-film mammograms, radiologists selected different digital processing algorithms for each of three mammographic reading tasks and for different lesion types. Soft-copy display will eventually allow radiologists to select among these options more easily.
Algorithms↗
Measuring and incorporating patient preferences and utilities in the assessment of diagnostic technology.
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Activities of Daily Living↗
Interpolation algorithms for digital mammography systems with multiple detectors.
RATIONALE AND OBJECTIVES: In some full-field digital mammography systems, multiple detectors are abutted together, and the physical gaps between adjacent detectors produce seams between the resultant subimages. In this study, a variety of interpolation algorithms for estimating the missing information in the seams were compared, and their effect on image quality was evaluated. MATERIALS AND METHODS: Eight representative interpolation algorithms were selected, including nearest neighbor, one-dimensional and two-dimensional weighting, mean value, one-dimensional and two-dimensional polynomial, and one-dimensional and two-dimensional cubic spline interpolation methods. These methods were applied to digital mammograms and phantom images. The effectiveness of each algorithm was evaluated for accuracy and geometric distortion. RESULTS: These interpolation algorithms offered similar accuracy in estimating missing image information. The weighting, polynomial, and cubic spline interpolation algorithms introduced less geometric distortion than the nearest neighbor and mean value interpolation algorithms. All algorithms were more effective in estimating larger, lower-contrast features (such as breast masses) than in estimating smaller, higher-contrast features (such as breast microcalcifications). Small microcalcifications within the seams cannot be recovered with interpolation. The probability of a microcalcification in a seam is small, however, and the failure to image a few microcalcifications of a cluster generally does not substantially alter diagnostic performance. CONCLUSION: In the development of full-field digital breast imaging systems, appropriate interpolation algorithms can satisfactorily fill in narrow gaps between adjacent detectors. The one-dimensional weighting interpolation method seems an effective and efficient choice.
Algorithms↗
Optical processing architecture and its potential application for digital and analog radiography.
In this report we introduce the fundamental architectures and the potential applications of optical processing techniques in medical imaging. Three basic optical processing architectures were investigated for digital and analog radiography. The processors consist of a module that converts either the analog or the digital radiograph into a coherent light distribution; a coherent optical processing architecture that performs various mathematical operations; a programmable digital-optical interface and other accessories. Optical frequency filters were implemented for mammographic and other clinical feature enhancement. In medical image processing, digital computers offer the advantages of programmability and flexibility. In contrast, optical processors perform parallel image processing with high speed. Optical processors also offer analog nature, compact size, and cost effectiveness. With technical advances of digital-optical interface devices, the medical image processor, in the foreseeable future, may be a hybrid device, namely, a programmable optical architecture.
Equipment Design↗
Rate of insufficient samples for fine-needle aspiration for nonpalpable breast lesions in a multicenter clinical trial: The Radiologic Diagnostic Oncology Group 5 Study. The RDOG5 investigators.
BACKGROUND: Radiologic Diagnostic Oncology Group 5 is a multicenter clinical trial designed to evaluate fine-needle aspiration (FNA) of nonpalpable breast lesions performed by multiple operators using the same protocol. METHODS: Four hundred and nineteen women with mammographically detected nonpalpable breast lesions were enrolled on the trial at 18 institutions. Group A institutions randomized women to stereotactically guided FNA (SFNA) followed by stereotactically guided core needle biopsy (SCNB), or SCNB only. Group B institutions randomized women to SFNA and SCNB, SCNB, or ultrasonographically guided FNA followed by ultrasonographically guided core needle biopsy (USCNB), or USCNB only. A total of 377 women were eligible for analysis. RESULTS: FNA yielded 128 insufficient samples for the 377 patients (33.95%; 95% confidence interval, 29.2-38.7%). The rate of insufficient samples varied by type of lesion with calcified lesions associated with a significantly higher rate of insufficient sampling than masses (P < 0.001). The radiologist's level of suspicion of the lesion was not a statistically significant predictor of insufficient samples for mass lesions, but was a predictor for calcified lesions. For the 336 lesions for which histologic information was available, insufficient samples occurred in significantly more benign than malignant lesions. CONCLUSIONS: The high rate of insufficient samples for FNA of nonpalpable breast lesions in this multicenter trial makes its use impractical in this setting. Because of this factor, the study was terminated early.
Adult↗
Placement of endovascular embolization microcoils to localize the site of breast lesions removed at stereotactic core biopsy.
In 13 cases, a breast abnormality was inadvertently removed during stereotactic core biopsy, and a 0.5- or 1.0-cm-long endovascular embolization microcoil was placed to mark the biopsy site. In seven patients, the microcoils allowed successful preoperative localization of the lesion site. In six patients, 6-month follow-up mammograms showed no change in microcoil position. Placement of embolization microcoils helped localize the site of breast lesions removed during stereotactic core biopsy.
Biopsy, Needle↗
Future directions in imaging of breast diseases.
In the near future, investigation and refinement of emerging anatomic and functional breast imaging techniques will enable clinical trials that will evaluate their utility and potential for improving the survival and quality of life for patients with breast cancer. In the longer term, strategic research collaborations among investigators in the fields of functional imaging, molecular biology, and pathology are needed to merge existing science and advance the development of biomarker and genetic techniques focused on detecting and characterizing disease at the cellular and molecular levels. This research could create clinical tools for (a) detecting breast cancer earlier, (b) more accurately quantifying the extent of disease, (c) noninvasively evaluating lymph node involvement, (d) identifying micrometastases and residual microscopic disease, and (e) enhancing therapy by means of imaging-guided biomarker or tumor-specific delivery of pharmacologic, chemosensitizing, or radiosensitizing agents to tumors.
Breast↗
The RSNA-AUR-ARRS introduction to research program for 2nd year radiology residents: effect on career choice and early academic performance. Radiological Society of North America. Association of University Radiologists. American Roentgen Ray Society.
PURPOSE: To evaluate graduates of the first 5 years of the Introduction to Research program, sponsored by the Radiological Society of North America, Association of University Radiologists, and American Roentgen Ray Society, to determine if they more frequently entered and demonstrated early success in academic careers than did nonparticipants. MATERIALS AND METHODS: In 1997, the authors surveyed all 396 program participants for the 1990-1995 period and 2,047 nonparticipants who were in the same residencies as the participants during that period. Career plans, research participation, and academic achievements were compared. RESULTS: The survey was completed by 321 participants (81%) and 1,153 nonparticipants (56%). More than a third of participants thought the program had a strong effect on their initial career decision. Forty-one percent of participants who completed training (n = 192) were currently in academia versus 26% of nonparticipants (n = 676; P = .001). Of the 321 participants, 35% believed they would spend most of their careers in academia and 15% thought research would be their major focus versus 19% and 8% for the 1,153 nonparticipants (P < .001). Participants had higher levels of academic achievement earlier in their careers than did nonparticipants. CONCLUSION: The Introduction to Research program is encouraging the development of successful research careers. However, the results may be influenced by the self- or departmental selection of participants who were oriented toward research independent of program participation.
Achievement↗
Percutaneous breast biopsy for nonpalpable lesions.
Increasingly, biopsies for suspected breast abnormalities are conducted by percutaneous needle extraction of core samples rather than by standard surgical excision or fine-needle aspiration (FNA) of cellular material. Core-needle biopsies are highly accurate and have many advantages over surgical excisions, including reduction of the morbidity and cost of breast disease diagnosis. Limitations include differentiating atypical ductal hyperplasia from ductal carcinoma in situ. Equipment and technique for stereotactic and ultrasound-guided core breast biopsy are discussed. Appropriate indications for core-needle biopsy, excisional biopsy after needle localization, and FNA are provided. Appropriate management after core-needle biopsy includes the establishment of concordance of histologic results with the level of suspicion of the mammographic findings to prevent false-negative core biopsies. A recommendation for return to regular mammographic screening, short-interval (6-month) mammographic follow-up, or repeat core or surgical appearance depends on this correlation.
Journal Article↗
Contrast-detail detectability analysis: comparison of a digital spot mammography system and an analog screen-film mammography system.
RATIONALE AND OBJECTIVES: The authors compared the contrast-detail detectability properties of an optically coupled charge-coupled device (CCD) digital mammography system with those of a conventional analog screen-film mammography system. METHODS: A proprietary contrast-detail phantom was imaged with both systems. Twelve observers viewed analog and digital images obtained at seven different mean glandular doses. Contrast-detail-dose curves were generated on the basis of the readers' visual perceptions. Interobserver errors were also calculated. In addition, the authors applied a theoretical model for lesion detectability to calculate and compare the digital and analog mammography systems. RESULTS: The readers' contrast-detail detectability was significantly superior with the digital system in the detail and contrast ranges evaluated (P < .001). CONCLUSION: The performance of the readers paralleled the performance predicted by the theoretical model for the two imaging systems. The following features account for the superior performance of the digital mammography system: (a) higher quantum efficiency of the phosphor, (b) wider dynamic range, (c) better contrast transfer characteristics, and, most important, (d) greater photon flux at the phosphor entrance.
Contrast Sensitivity↗
Diagnostic efficacy of compressed digitized real-time sonography of uterine fibroids.
RATIONALE AND OBJECTIVES: The authors investigated the diagnostic efficacy of compression of real-time ultrasound (US) examinations. METHODS: Low- and high-compression recordings (9:1 and 15:1, respectively) of examinations were generated by using Joint Photographic Experts Group algorithms. Seven radiologists used a five-level response scale to answer questions about the presence, number, and location of focal fibroid tumors in 67 randomly sorted uterine examinations. The images were viewed after no, low, and high compression. Results were evaluated by using multipatient, multireader receiver operating characteristic jack-knife analysis. RESULTS: Given the reduction in the US digital video rates from 74 Mbit/sec for uncompressed images to 8 Mbit/sec for low compression and 4.7 Mbit/sec for high compression, there were no statistically significant differences in accuracy between the compression schemes. Confidence intervals suggested that the sample size was adequate. CONCLUSION: Compressed images with compression ratios of 9:1 and 15:1 were diagnostically equivalent to uncompressed images of uterine fibroid tumors.
Female↗
Association of breast cancer with the finding of atypical ductal hyperplasia at core breast biopsy.
OBJECTIVE: The purpose of the study is to evaluate the prevalence of occult breast carcinoma in surgical breast biopsies performed on nonpalpable breast lesions diagnosed initially as atypical ductal hyperplasia (ADH) by core needle biopsy. BACKGROUND: Atypical ductal hyperplasia is a lesion with significant malignant potential. Some authors note that ADH and ductal carcinoma in situ (DCIS) frequently coexist in the same lesion. The criterion for the diagnosis of DCIS requires involvement of at least two ducts; otherwise, a lesion that is qualitatively consistent with DCIS but quantitatively insufficient is described as atypical ductal hyperplasia. Thus, the finding of ADH in a core needle breast biopsy specimen actually may represent a sample of a true in situ carcinoma. METHODS: Between May 3, 1994, and June 12, 1996, image-guided core biopsies of 510 mammographically identified lesions were performed using a 14-gauge automated device with an average of 7.5 cores obtained per lesion. Atypical ductal hyperplasia was found in 23 (4.5%) of 510 lesions, and surgical excision subsequently was performed in 21 of these cases. In these 21 cases, histopathologic results from core needle and surgical biopsies were reviewed and correlated. RESULTS: Histopathologic study of the 21 surgically excised lesions having ADH in their core needle specimens showed seven (33.3%) with DCIS. CONCLUSIONS: In the authors' patient population, one third of patients with ADH at core biopsy have an occult carcinoma. A core needle breast biopsy finding of ADH for nonpalpable lesions therefore warrants a recommendation for excisional biopsy.
Biopsy, Needle↗