HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Yang, W. T. Articles by Dempsey, P. J. Search for Related Content PubMed PubMed Citation Articles by Yang, W. T. Articles by Dempsey, P. J.

Needle Localization for Excisional Biopsy of Breast Lesions: Comparison of Effect of Use of Full-Field Digital versus Screen-Film Mammographic Guidance on Procedure Time¹

¹ From the Division of Diagnostic Imaging (W.T.Y., G.J.W., A.C.K., P.J.D.), Department of Biostatistics (M.M.J.), Division of Cancer Medicine (M.B.C.), and Division of Surgery (K.K.H.), University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Blvd, Unit 57, Houston, TX 77030. From the 2002 RSNA scientific assembly. Received January 16, 2003; revision requested March 26; final revision received July 21; accepted August 22. Address correspondence to W.T.Y. (e-mail: wyang@di.mdacc.tmc.edu).

	ABSTRACT

TOP ABSTRACT INTRODUCTION Materials and Methods Results Discussion REFERENCES

 
The time required to perform needle localization with full-field digital (FFD) mammography was compared with the time required to perform it with screen-film (SF) mammography in 158 women with breast lesions. The time needed to position the patient before the first image was acquired, needle placement time, and total procedure time were compared between techniques. Regression modeling was performed to assess the effect of mammographic guidance method while simultaneously adjusting for other significant covariates. By using the backward selection technique, statistically nonsignificant variables were removed one at a time to produce a final model for which all statistically significant effects were defined as those with P < .10. Total procedure time for all lesions was shorter with FFD than with SF mammography. The time needed to position the patient and needle placement time were also significantly shorter with FFD than with SF mammography. Procedure time for needle localization of breast lesions is significantly shorter with FFD than with SF mammographic guidance.

© RSNA, 2004

Index terms: Breast, biopsy, 00.1261 • Breast neoplasms, localization, 00.1261 • Breast radiography, 00.112, 00.1215 • Breast radiography, comparative studies, 00.112, 00.1215 • Radiography, digital, 00.1215

	INTRODUCTION

TOP ABSTRACT INTRODUCTION Materials and Methods Results Discussion REFERENCES

 
To date, the most effective method for early detection of breast cancer is x-ray mammography, and among x-ray mammography systems, screen-film mammography has become the standard of reference in early breast cancer detection (1,2). The advantages of screen-film mammography include low cost, acceptable image quality with proper exposure, and ease of image viewing. However, current screen-film mammography systems are limited by a relatively narrow dynamic range, low contrast resolution, film noise, and film processing artifacts. In screen-film mammography, the film serves three functions: image acquisition, storage, and display. In digital systems, the tasks of image acquisition, display, and storage are separated, an arrangement that allows for the potential optimization of each function independently. Digital mammography systems may yield improved image quality and possibly reduce a patient’s radiation exposure (3). Furthermore, digital mammography systems may allow for improved efficiency because delays due to film processing are eliminated.

Recently, whole-breast digital imaging systems have been introduced, and flat-panel–based digital x-ray imaging systems have become commercially available for general radiography applications. The first commercially available Food and Drug Administration–approved full-field digital mammography unit, Senographe (GE Medical Systems, Milwaukee, Wis), involves use of an amorphous thallium-doped silicon cesium iodide detector. The Senographe detector incorporates active-matrix arrays of integrated electronic circuits and amorphous silicon thin-film transistors that are deposited on large-area glass substrates.

Results of previous studies have shown that, as compared with screen-film mammography systems, flat-panel–based detectors generally have a substantially higher detective quantum efficiency, which may lead to improved microcalcification detection and better low-contrast performance in general (4,5). This performance improvement has been evaluated and investigated with perception studies involving relevant diagnostic tasks (6,7). A recent comparison of full-field digital mammography with screen-film mammography for cancer detection revealed no difference in cancer detection and indicated that the use of full-field digital mammography resulted in fewer patient recalls than did the use of screen-film mammography (8,9).

We hypothesized that digital mammography systems improve efficiency because delays due to film processing are eliminated and technologists can verify positioning and check image quality on a monitor within seconds after an exposure. Thus, the amount of time that a woman’s breast is in compression is reduced, as is the overall procedure time. The purpose of our study was to determine whether full-field digital mammography requires less, more, or as much procedure time as screen-film mammography for needle localization of breast lesions prior to excisional biopsy.

	Materials and Methods

TOP ABSTRACT INTRODUCTION Materials and Methods Results Discussion REFERENCES

 
Patients and Equipment
One hundred fifty-eight consecutive women underwent mammography for needle localization of breast masses (69 patients), calcifications (75 patients), architectural distortion (four patients), tumor marker coils (three patients), or stereotactic clips (seven patients) prior to excisional biopsy. Tumor marker coils had been placed to mark the sites of residual tumors treated with neoadjuvant chemotherapy, and stereotactic clips marked the sites of previous percutaneous biopsies of nonpalpable tumors that had been performed with stereotactic guidance. Institutional review board approval, with waiver of informed consent, was obtained for this study.

Eighty patients underwent needle localization with screen-film mammographic guidance that was provided with a DMR plus unit (GE Medical Systems), and 78 patients underwent needle localization with full-field digital mammographic guidance that was provided with a Senographe unit. The screen-film system used was the MinR-2000 screen and MinR-2000 film combination (Eastman Kodak, Rochester, NY). Hard-copy screen-film mammograms were processed with a Kodak X-OMAT Multiloader 300 Processor (Eastman Kodak). Soft-copy full-field digital mammograms were read at a 38 x 28-cm M20L acquisition workstation monitor (Image Systems, Minnetonka, Minn) with a matrix of 1,280 x 1,024 pixels, yielding a pixel size of approximately 28 µm for display.

The patients were assigned to the two groups in consecutive cohorts before and after the installation of a full-field digital mammography unit at our institution. Through 2000, prior to the availability of full-field digital mammography, all patients were assigned to the screen-film mammography group. Once the full-field digital mammography unit became available, all subsequent patients were assigned to the full-field digital mammography group. All needle localization procedures at our institution were performed with full-field digital mammography from that point forward. Although patient assignment was not randomized for this study, we believe that there was no selection bias in that all patients were assigned consecutively to a single group at the same institution during a defined time period. The protocol for needle localization was identical with both full-field digital and screen-film mammography. The median patient age was 54 years in both the full-field digital mammography group (age range, 28–76 years) and the screen-film mammography group (age range, 26–78 years).

Data Collection
Data on mammographically guided needle localization procedure times were collected for all patients. The technologist who performed the procedure recorded these data. Data collection was performed by using soft-copy full-field digital mammography and hard-copy screen-film mammography. Time A was defined as the time from the patient’s entry into the room to the time that the lesion was appropriately positioned in the field so that needle localization could be performed. Time B was designated as the time from when the first image was acquired to the time when the last image was acquired. Needle localization was performed during time B. The total procedure time was designated as time A + time B.

Additional information collected for each patient included the number of each lesion type described above. The sizes of the individual masses and calcification clusters that were targeted were recorded. Lesions were categorized into the following three groups according to size: lesions smaller than 1 cm, lesions between 1 and 2 cm in size, and lesions larger than 2 cm. For patients with multiple lesions, the largest lesion was used for the per-patient analysis of lesion size. The location of each lesion was categorized as being in the upper or the lower half of the breast or along the 3-o’clock–to–9-o’clock axis. The number of needles used per case was recorded. Each procedure involved one radiologist and one technologist, and the names and experience levels of the radiologist and technologist performing each procedure were recorded. A total of eight different radiologists (including G.J.W., A.C.K., and P.J.D.) and 14 different technologists were involved in the needle localization procedures.

Statistical Analysis
Regression modeling was performed to assess the effect of mammographic guidance method on procedure time while simultaneously adjusting for other significant covariates. By using the backward selection technique, statistically nonsignificant variables were removed one at a time to produce a final model for which all statistically significant effects were defined as those with P values of less than .10. To determine the effect of mammographic method on needle placement and total procedure time for all lesions, the initial regression model included as independent variables the method of mammography; lesion type, size, and location; the number of needles used; the number of lesions; and the individual radiologist and technologist. Similarly, to study the effect of type of mammography on positioning time for all lesions, the initial regression model included method of mammography; lesion type, size, and location; and the individual radiologist and technologist. All statistical analyses were performed by using SAS software release 8.1 (SAS Institute, Cary, NC).

	Results

TOP ABSTRACT INTRODUCTION Materials and Methods Results Discussion REFERENCES

 
Patient characteristics, including number of lesions, lesion type, and lesion size, are detailed for the two groups in Table 1. Mean time variables (time A, time B, and time A + time B) with each kind of mammographic guidance are given in Table 2. Significant variables predicting positioning, needle placement, and total procedure times for all lesions and the lesion subsets of masses and calcifications are detailed in Table 3. Mean total procedure time for all lesions was shorter with full-field digital mammography (42.3 minutes) than with screen-film mammography (50.8 minutes, P < .001). Other significant variables in the regression model included number of needles (P < .001), lesion location (P = .005), and the individual radiologist performing the procedure (P < .01). For all lesions, mean positioning times (13.2 vs 17.9 minutes, P = .003) and mean needle placement times (29.1 vs 32.8 minutes, P < .02) were shorter with full-field digital mammography than with screen-film mammography. Mean total procedure time was shorter with full-field digital mammography (41.4 minutes) than with screen-film mammography (48.5 minutes, P < .01) for the calcification subgroup as well as for the mass subgroup (43.4 vs 52.9 minutes, P < .05).

	Discussion

TOP ABSTRACT INTRODUCTION Materials and Methods Results Discussion REFERENCES

In our experience, changing from screen-film mammography to full-field digital mammography significantly decreased needle localization procedure time. While the total procedure time savings of approximately 8 minutes resulting from the use of full-field digital rather than screen-film mammographic guidance for needle localization may not be a large enough time reduction to substantially affect workflow in facilities where needle localization is not performed in great volume, the use of full-field digital mammography resulted in a significant time reduction in our facility, where up to three needle localization procedures are performed each morning and many procedures involve bracketing the lesion with multiple needles. Although the time saved during each procedure is relatively small, the time reduction occurs while the patient remains stationary with the breast in compression. Thus, the use of full-field digital mammography may also potentially contribute to a substantial reduction in patient discomfort.

To the best of our knowledge, results of no similar comparison studies of needle localization procedure time that involved the use of full-field digital mammography have been reported in the literature. The amount of time saved in our study was not as great as that observed with use of a small-field-of-view digital system in a study in which that system was compared with screen-film mammography for needle localization (3). Dershaw et al (3) observed a 50% reduction in needle localization procedure time with use of a prototype small-field-of-view (5 x 5 cm) digital mammography unit.

With screen-film mammography units, stereotactic biopsy has been reported to take 20–50 minutes (10–12), whereas with digital units that are used with patients in the prone position, stereotactic biopsies have been reported to take 15–20 minutes (13). Comparative studies in which investigators evaluated the effect of use of full-field digital versus screen-film mammography on the accuracy of core biopsy of microcalcifications performed with upright stereotactic guidance revealed that biopsy with full-field digital mammography had a significantly higher success rate for accurately obtaining calcifications—even in lesions with fewer calcifications—as well as improved sensitivity in the diagnosis of ductal carcinoma in situ (10,11).

Most of the time saved in this study appeared to come from the speed involved in displaying digital images (15 seconds per image) rather than processing films (3 minutes per image). Perhaps the improved time efficiency occurred because there is no film development time with full-field digital mammography systems. Compared with the time required to perform needle localization with screen-film mammography systems, 8–10 minutes can be saved per needle localization procedure when full-field digital mammography systems are used. In our study, the varying skill levels of the multiple individuals who performed needle localization—ranging from trainees to experienced breast imagers—also had an effect on the overall total procedure time. Additionally, multiple patient-related factors that play an important role in the time required for needle localization, such as the time to explain the procedure to the patients and the time for preparation of equipment and supplies, cannot be made more time-efficient by using a full-field digital mammography unit.

Digital mammograms can be presented on laser-printed film or at a high-spatial-resolution computer workstation, also known as a soft-copy display system (13). Currently, only cathode ray tube technology supports the requirements for soft-copy display of digital mammograms in that it can enable the display of mammograms completely on the monitors at full spatial resolution. The pixel size of approximately 28 µm with our acquisition workstation monitor was not a limiting factor for system resolution in this study. Instead, the 100-µm detection element of the full-field digital mammography unit was a limiting factor and may have affected the display of microcalcifications in our study. The efficiency of needle localization in the targeting of subtle calcifications may be improved through the application of image processing software to increase the conspicuity of calcifications nearly instantaneously.

Further limitations of this study included the relatively small study population and the multiple potentially significant covariates of different patients, lesion types, and radiologists and technologists performing the procedures. Although lesion type and individual technologist were not found at multivariate regression analysis to be significant variables in determining procedure time in this study, the individual radiologist performing each procedure did significantly affect procedure time. At the time of this study, there were eight radiologists of varying skill and experience performing needle localization at our institution, a teaching hospital, as well as less-experienced rotating fellows and residents. A further limitation was that data on the number of exposures and the number of films obtained per needle localization procedure—potentially significant variables—were not collected during the study period and thus could not be analyzed in this study. Similarly, breast density, a factor that may potentially affect procedure time, was not compared between the two patient groups.

In conclusion, as digital technology continues to improve and digital mammography becomes less expensive, further study is needed to determine whether the use of digital mammography will contribute substantially to making needle localization procedures more time efficient.

	FOOTNOTES

 
G.J.W. is a stockholder in General Electric and reports participation in research agreements with and receipt of research support from General Electric.

Author contributions: Guarantors of integrity of entire study, W.T.Y., G.J.W.; study concepts, G.J.W., A.C.K., K.K.H.; study design, W.T.Y., G.J.W., M.M.J., K.K.H.; literature research, W.T.Y., G.J.W., M.M.J., M.B.C.; clinical studies, G.J.W., A.C.K., K.K.H., P.J.D.; data acquisition, W.T.Y., G.J.W., M.B.C., A.C.K., K.K.H., P.J.D.; data analysis/interpretation, W.T.Y., M.M.J., M.B.C., P.J.D.; statistical analysis, W.T.Y., M.M.J.; manuscript preparation, W.T.Y., M.M.J., G.J.W.; manuscript definition of intellectual content, W.T.Y., G.J.W.; manuscript editing, revision/review, and final version approval, all authors

	REFERENCES

TOP ABSTRACT INTRODUCTION Materials and Methods Results Discussion REFERENCES

 

1. Verbeek AL, Hendriks JH, Holland R, Mravunac M, Sturmans F, Day NE. Reduction of breast cancer mortality through mass screening with modern mammography. Lancet 1984; 1:1222-1224.[Medline]
2. Howard J. Using mammography for cancer control: an unrealized potential. CA Cancer J Clin 1987; 37:33-48.[Free Full Text]
3. Dershaw DD, Fleischman RC, Liberman L, Deutch B, Abramson AF, Hann L. Use of digital mammography in needle localization procedures. AJR Am J Roentgenol 1993; 161:559-562.[Abstract/Free Full Text]
4. Siewerdsen JH, Antonuk LE, El-Mohri Y, Yorkston J, Huang W, Cunningham IA. Signal, noise power spectrum, and detective quantum efficiency of indirect-detection flat-panel imagers for diagnostic radiology. Med Phys 1998; 25:614-628.[CrossRef][Medline]
5. Zhao W, Rowlands JA. Digital radiology using active matrix readout of amorphous selenium: theoretical analysis of detective quantum efficiency. Med Phys 1997; 24:1819-1833.[CrossRef][Medline]
6. Chan HP, Helvie MA, Petrick N. Digital mammography: observer performance study of the effects of pixel size on the characterization of malignant and benign microcalcifications. Acad Radiol 2001; 8:454-466.[CrossRef][Medline]
7. Rong XJ, Shaw CC, Johnston DA, et al. Microcalcification detectability for four mammographic detectors: flat-panel CCD, CR, and screen-film. Med Phys 2002; 29:2052-2061.[CrossRef][Medline]
8. Lewin JM, Hendrick RE, D’Orsi CJ, et al. Comparison of full-field digital mammography and screen-film mammography for cancer detection: results of 4,945 paired examinations. Radiology 2001; 218:873-880.[Abstract/Free Full Text]
9. Lewin JM, D’Orsi CJ, Hendrick RE, et al. Clinical comparison of full-field digital mammography and screen-film mammography for detection of breast cancer. AJR Am J Roentgenol 2002; 179:671-677.[Abstract/Free Full Text]
10. Whitlock JP, Evans AJ, Burrell HC, et al. Digital imaging improves upright stereotactic core biopsy of mammographic microcalcifications. Clin Radiol 2000; 55:374-377.[CrossRef][Medline]
11. Becker L, Taves D, McCurdy L, Muscedere G, Karlik S, Ward S. Stereotactic core biopsy of breast microcalcifications: comparison of film versus digital mammography, both using an add-on unit. AJR Am J Roentgenol 2001; 177:1451-1457.[Abstract/Free Full Text]
12. Caines JS, McPhee MD, Konok GP, Wright BA. Stereotaxic needle core biopsy of breast lesions using a regular mammographic table with an adaptable stereotaxic device. AJR Am J Roentgenol 1994; 163:317-321.[Abstract/Free Full Text]
13. Liberman L, Dershaw DD, Rosen PP, Abramson , AF , Deutch BM, Hann LE. Stereotaxic 14-gauge breast biopsy: how many core biopsy specimens are needed? Radiology 1994; 192:793-795.[Abstract/Free Full Text]

This article has been cited by other articles:

				N. Cho and W. K. Moon Digital Mammography-Guided Skin Marking for Sonographically Guided Biopsy of Suspicious Microcalcifications Am. J. Roentgenol., March 1, 2009; 192(3): W132 - W136. [Abstract] [Full Text] [PDF]

				J. H. BRUSIN Digital Mammography: An Update Radiol. Technol., January 1, 2006; 77(3): 226M - 234M. [Abstract] [Full Text] [PDF]

This Article Abstract Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Yang, W. T. Articles by Dempsey, P. J. Search for Related Content PubMed PubMed Citation Articles by Yang, W. T. Articles by Dempsey, P. J.