Gordon S. Abrams

Digital Breast Tomosynthesis: Observer Performance Study

OBJECTIVE The purpose of this study was to compare in a retrospective observer study the diagnostic performance of full-field digital mammography (FFDM) with that of digital breast tomosynthesis. MATERIALS AND METHODS Eight experienced radiologists interpreted images from 125 selected examinations, 35 with verified findings of cancer and 90 with no finding of cancer. The four display conditions included FFDM alone, 11 low-dose projections, reconstructed digital breast tomosynthesis images, and a combined display mode of FFDM and digital breast tomosynthesis images. Observers rated examinations using the screening BI-RADS rating scale and the free-response receiver operating characteristic paradigm. Observer performance levels were measured as the proportion of examinations prompting recall of patients for further diagnostic evaluation. The results were presented in terms of true-positive fraction and false-positive fraction. Performance levels were compared among the acquisitions and reading modes. Time to view and interpret an examination also was evaluated. RESULTS Use of the combination of digital breast tomosynthesis and FFDM was associated with 30% reduction in recall rate for cancer-free examinations that would have led to recall if FFDM had been used alone (p < 0.0001 for the participating radiologists, p = 0.047 in the context of a generalized population of radiologists). Use of digital breast tomosynthesis alone also tended to reduce recall rates, an average of 10%, although the observed decrease was not statistically significant (p = 0.09 for the participating radiologists). There was no convincing evidence that use of digital breast tomosynthesis alone or in combination with FFDM results in a substantial improvement in sensitivity. CONCLUSION Use of digital breast tomosynthesis for breast imaging may result in a substantial decrease in recall rate.

Digital Breast Tomosynthesis: A Pilot Observer Study

OBJECTIVE The objective of our study was to assess ergonomic and diagnostic performance-related issues associated with the interpretation of digital breast tomosynthesis-generated examinations. MATERIALS AND METHODS Thirty selected cases were read under three different display conditions by nine experienced radiologists in a fully crossed, mode-balanced observer performance study. The reading modes included full-field digital mammography (FFDM) alone, the 11 low-dose projections acquired for the reconstruction of tomosynthesis images, and the reconstructed digital breast tomosynthesis examination. Observers rated cases under the free-response receiver operating characteristic, as well as a screening paradigm, and provided subjective assessments of the relative diagnostic value of the two digital breast tomosynthesis-based image sets as compared with FFDM. The time to review and diagnose each case was also evaluated. RESULTS Observer performance measures were not statistically significant (p > 0.05) primarily because of the small sample size in this pilot study, suggesting that showing significant improvements in diagnosis, if any, will require a larger study. Several radiologists did perceive the digital breast tomosynthesis image set and the projection series to be better than FFDM (p < 0.05) for diagnosing this specific case set. The time to review, interpret, and rate the examinations was significantly different for the techniques in question (p < 0.05). CONCLUSION Tomosynthesis-based breast imaging may have great potential, but much work is needed before its optimal role in the clinical environment is known.

Ultrasound Guided Core Biopsy versus Fine Needle Aspiration for Evaluation of Axillary Lymphadenopathy in Patients with Breast Cancer

Rationale and Objectives. To compare the sensitivities of ultrasound guided core biopsy and fine needle aspiration (FNA) for detection of axillary lymph node metastases in patients with a current diagnosis of ipsilateral breast cancer. Materials and Methods. From December 2008 to December 2010, 105 patients with breast cancer and abnormal appearing lymph nodes in the ipsilateral axilla consented to undergo FNA of an axillary node immediately followed by core biopsy of the same node, both with ultrasound guidance. Experienced pathologists evaluated the aspirate cytology without knowledge of the core histology. Cytology and core biopsy results were compared to sentinel node excision or axillary dissection pathology. Sensitivities were compared using McNemars test. Results. Of 70 patients with axillary node metastases, FNA was positive in 55/70 (78.6%) and core was positive in 61/70 (87.1%) (P = 0.18). The FNA and core results were discordant in 14/70 (20%) patients. Ten cases were FNA negative/core positive. Four cases were FNA positive/core negative. Conclusion. Core biopsy detected six (8.6%) more cases of metastatic lymphadenopathy than FNA but the difference in sensitivities was not statistically significant. Core biopsy should be considered if the node is clearly imaged and readily accessible. FNA is a good alternative when a smaller needle is desired due to node location or other patient factors. This trial is registered with NCT01920139.

Detection of breast abnormalities using a prototype resonance electrical impedance spectroscopy system: A preliminary study

Electrical impedance spectroscopy has been investigated with but limited success as an adjunct procedure to mammography and as a possible pre-screening tool to stratify risk for having or developing breast cancer in younger women. In this study, the authors explored a new resonance frequency based [resonance electrical impedance spectroscopy (REIS)] approach to identify breasts that may have highly suspicious abnormalities that had been recommended for biopsies. The authors assembled a prototype REIS system generating multifrequency electrical sweeps ranging from 100 to 4100 kHz every 12 s. Using only two probes, one in contact with the nipple and the other with the outer breast skin surface 60 mm away, a paired transmission signal detection system is generated. The authors recruited 150 women between 30 and 50 years old to participate in this study. REIS measurements were performed on both breasts. Of these women 58 had been scheduled for a breast biopsy and 13 had been recalled for additional imaging procedures due to suspicious findings. The remaining 79 women had negative screening examinations. Eight REIS output signals at and around the resonance frequency were computed for each breast and the subtracted signals between the left and right breasts were used in a simple jackknifing method to select an optimal feature set to be inputted into a multi-feature based artificial neural network (ANN) that aims to predict whether a womans breast had been determined as abnormal (warranting a biopsy) or not. The classification performance was evaluated using a leave-one-case-out method and receiver operating characteristics (ROC) analysis. The study shows that REIS examination is easy to perform, short in duration, and acceptable to all participants in terms of comfort level and there is no indication of sensation of an electrical current during the measurements. Six REIS difference features were selected as input signals to the ANN. The area under the ROC curve (Az) was 0.707±0.033 for classifying between biopsy cases and non-biopsy (including recalled and screening negative) and the performance (Az) increased to 0.746±0.033 after excluding recalled but negative cases. At 95% specificity, the sensitivity levels were approximately 20.5% and 30.4% in the two data sets tested. The results suggest that differences in REIS signals between two breasts measured in and around the tissue resonance frequency can be used to identify at least some of the women with suspicious abnormalities warranting biopsy with high specificity.