Christiane M. Hakim

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.

Detection and Classification of Calcifications on Digital Breast Tomosynthesis and 2D Digital Mammography: A Comparison

OBJECTIVE The purpose of this article is to compare the ability of digital breast tomosynthesis and full field digital mammography (FFDM) to detect and characterize calcifications. MATERIALS AND METHODS One hundred paired examinations were performed utilizing FFDM and digital breast tomosynthesis. Twenty biopsy-proven cancers, 40 biopsy-proven benign calcifications, and 40 randomly selected negative screening studies were retrospectively reviewed by five radiologists in a crossed multireader multimodal observer performance study. Data collected included the presence of calcifications and forced BI-RADS scores. Receiver operator curve analysis using BI-RADS was performed. RESULTS Overall calcification detection sensitivity was higher for FFDM (84% [95% CI, 79-88%]) than for digital breast tomosynthesis (75% [95% CI, 70-80%]). [corrected] In the cancer cohort, 75 (76%) of 99 interpretations identified calcification in both modes. Of those, a BI-RADS score less than or equal to 2 was rendered in three (4%) and nine (12%) cases with FFDM and digital breast tomosynthesis, respectively. In the benign cohort, 123 (62%) of 200 interpretations identified calcifications in both modes. Of those, a BI-RADS score greater than or equal to 3 was assigned in 105 (85%) and 93 (76%) cases with FFDM and digital breast tomosynthesis, respectively. There was no significant difference in the nonparametric computed area under the receiver operating characteristic curves (AUC) using the BI-RADS scores (FFDM, AUC = 0.76 and SD = 0.03; digital breast tomosynthesis, AUC = 0.72 and SD = 0.04 [p = 0.1277]). CONCLUSION In this small data set, FFDM appears to be slightly more sensitive than digital breast tomosynthesis for the detection of calcification. However, diagnostic performance as measured by area under the curve using BI-RADS was not significantly different. With improvements in processing algorithms and display, digital breast tomosynthesis could potentially be improved for this purpose.

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.

Digital Breast Tomosynthesis in the Diagnostic Environment: A Subjective Side-by-Side Review

OBJECTIVE The purpose of our study was to subjectively compare additional mammographic views to digital breast tomosynthesis (DBT) in the characterizing of known masses, architectural distortions, or asymmetries. MATERIALS AND METHODS Four experienced radiologists serially reviewed the imaging studies of 25 women with known masses, including full-field digital mammography (FFDM), additional views, and DBT. After review of the examinations, radiologists rated their relative preference in terms of classifying the finding in question when aided by the additional views versus aided by DBT, their combined diagnostic BI-RADS rating of the finding when both examinations were available, and whether or not they felt comfortable eliminating ultrasound in the specific cases being evaluated as a result of the DBT. RESULTS FFDM and DBT (combined) were perceived to be better for diagnosis in 50% (50/100) of the ratings (25 cases x four readers = 100 ratings) compared with FFDM and additional diagnostic views. Over all readers, 92% of the ratings for verified cancer cases and 50% of the ratings for high-risk cases were rated as BI-RADS 4 or 5. In 12% (12/100) of the ratings, radiologists indicated that the availability of DBT would have eliminated the need for ultrasound as a part of the diagnostic process. CONCLUSION DBT may be an alternative to obtaining additional mammographic views in most but not all cases of patients with a lesion that is not solely calcifications. In a fraction of cases, the use of DBT may eliminate the need for ultrasound.

Recall and detection rates in screening mammography: A review of clinical experience: Implications for practice guidelines

The authors investigated the correlation between recall and detection rates in a group of 10 radiologists who had read a high volume of screening mammograms in an academic institution.

Localized detection and classification of abnormalities on FFDM and tomosynthesis examinations rated under an FROC paradigm.

OBJECTIVE The purpose of our study was to assess diagnostic performance when retrospectively interpreting full-field digital mammography (FFDM) and breast tomosynthesis examinations under a free-response receiver operating characteristic (FROC) paradigm. MATERIALS AND METHODS We performed FROC analysis of a previously reported study in which eight experienced radiologists interpreted 125 examinations, including 35 with verified cancers. The FROC paradigm involves detecting, locating, and rating each suspected abnormality. Radiologists reviewed and rated both FFDM alone and a combined display mode of FFDM and digital breast tomosynthesis (DBT) (combined). Observer performance levels were assessed and compared with respect to the fraction of correctly identified abnormalities, the number of reported location-specific findings (both true and false), and their associated ratings. The analysis accounts for the number and locations of findings and the location-based ratings using a summary performance index (Λ), which is the FROC analog of the area between the receiver operating characteristic curve and the diagonal (chance) line. RESULTS Under the FROC paradigm, each reader detected more true abnormalities associated with cancer, or a higher true-positive fraction, under the combined mode. In an analysis focused on both the number of findings and associated location-based ratings, each of the radiologists performed better under the combined mode compared with FFDM alone, with increases in Λ ranging from 5% to 34%. On average, under the combined mode radiologists achieved a 16% improvement in Λ compared with the FFDM alone mode (95% CI, 7-26%; p < 0.01). CONCLUSION We showed that DBT-based breast imaging in combination with FFDM could result in better performance under the FROC paradigm.

Endoanal ultrasound findings and fecal incontinence symptoms in women with and without recognized anal sphincter tears

OBJECTIVE: To estimate whether endoanal ultrasound findings are more prevalent in primiparous women with a history of anal sphincter tear than in women without this history and whether the findings are associated with fecal incontinence symptoms. METHODS: A total of 251 primiparous women at seven clinical sites underwent standardized ultrasound assessment of the internal and external anal sphincter 6–12 months after delivery. Participants were women in the three cohorts of the Childbirth and Pelvic Symptoms Study: 1) women with clinically evident third- or fourth-degree tear at vaginal delivery (n=106); 2) no tear at vaginal delivery (n=106); and 3) cesarean delivery without labor (n=39). Women completed the Fecal Incontinence Severity Index to assess fecal incontinence symptoms. RESULTS: Thirty-five percent of the sphincter tear group exhibited internal sphincter gaps compared with 3% of vaginal controls (odds ratio [OR] 18.4, 95% confidence interval [CI] 5.5–62.1) and 10% of cesarean controls. External sphincter gaps were identified in 51% of the tear group compared with 31% of vaginal controls (OR 2.3, 95% CI 1.3–4.0) and 28% of cesarean controls. In the tear group, fecal incontinence severity was greater in those with internal sphincter gaps compared with those with no internal sphincter gaps (Fecal Incontinence Severity Index score 6.6±8.3 compared with 3.3±6.1, P=.02), as well as in those with external sphincter gaps (6.1±8.4 compared with 2.7±5.0, P=.01), and greatest in those with both internal and external sphincter gaps compared with at least one gap not present (7.2±8.1 compared with 3.4±6.4, P=.003). CONCLUSION: Anal sphincter gaps detected by ultrasonography are prevalent in postpartum primiparous women with a history of sphincter tear and are associated with fecal incontinence severity. LEVEL OF EVIDENCE: II-2

Detection and classification performance levels of mammographic masses under different computer-aided detection cueing environments1

Abstract Rationale and objectives The authors evaluated the impact of different computer-aided detection (CAD) cueing conditions on radiologists’ performance levels in detecting and classifying masses depicted on mammograms. Materials and methods In an observer performance study, eight radiologists interpreted 110 subtle cases six times under different display conditions to detect depicted masses and classify them as benign or malignant. Forty-five cases depicted biopsy-proven masses and 65 were negative. One mass-based cueing sensitivity of 80% and two false-positive cueing rates of 1.2 and 0.5 per image were used in this study. In one mode, radiologists first interpreted images without CAD results, followed by the display of cues and reinterpretation. In another mode, radiologists viewed CAD cues as images were presented and then interpreted images. Free-response receiver operating characteristic method was used to analyze and compare detection performance. The receiver operating characteristic method was used to evaluate classification performance. Results At these performance levels, providing cues after initial interpretation had little effect on the overall performance in detecting masses. However, in the mode with the highest false-positive cueing rate, viewing CAD cues immediately upon display of images significantly reduced average performance for both detection and classification tasks ( P Conclusion CAD systems with low sensitivity (≤80% on mass-based detection) and high false-positive rate (≥0.5 per image) in a dataset with subtle abnormalities had little effect on radiologists’ performance in the detection and classification of mammographic masses.

Reproducibility of Dynamic MR Imaging Pelvic Measurements : A Multi-institutional Study

PURPOSE To assess the reproducibility of bone and soft-tissue pelvimetry measurements obtained from dynamic magnetic resonance (MR) imaging studies in primiparous women across multiple centers. MATERIALS AND METHODS All subjects prospectively gave consent for participation in this institutional review board-approved, HIPAA-compliant study. At six clinical sites, standardized dynamic pelvic 1.5-T multiplanar T2-weighted MR imaging was performed in three groups of primiparous women at 6-12 months after birth: Group 1, vaginal delivery with anal sphincter tear (n = 93); group 2, vaginal delivery without anal sphincter tear (n = 79); and group 3, cesarean delivery without labor (n = 26). After standardized central training, blinded readers at separate clinical sites and a blinded expert central reader measured nine bone and 10 soft-tissue pelvimetry parameters. Subsequently, three readers underwent additional standardized training, and reread 20 MR imaging studies. Measurement variability was assessed by using intraclass correlation for agreement between the clinical site and central readers. Acceptable agreement was defined as an intraclass correlation coefficient (ICC) of at least 0.7. RESULTS There was acceptable agreement (ICC range, 0.71-0.93) for eight of 19 MR imaging parameters at initial readings of 198 subjects. The remaining parameters had an ICC range of 0.13-0.66. Additional training reduced measurement variability: Twelve of 19 parameters had acceptable agreement (ICC range, 0.70-0.92). Correlations were greater for bone (ICC, >or=0.70 in five [initial readings] and eight of nine [rereadings] variables) than for soft-tissue measurements (ICC, >or=0.70 in three [initial readings] of 10 and four [rereadings] of 10 readings, respectively). CONCLUSION Despite standardized central training, there is high variability of pelvic MR imaging measurements among readers, particularly for soft-tissue structures. Although slightly improved with additional training, measurement variability adversely affects the utility of many MR imaging measurements for multicenter pelvic floor disorder research.

Magnetic resonance assessment of pelvic anatomy and pelvic floor disorders after childbirth

To compare pelvic anatomy, using magnetic resonance imaging, between postpartum women with or without pelvic floor disorders. We measured postpartum bony and soft tissue pelvic dimensions in 246 primiparas, 6–12-months postpartum. Anatomy was compared between women with and without urinary or fecal incontinence, or pelvic organ prolapse; P < 0.01 was considered statistically significant. A deeper sacral hollow was significantly associated with fecal incontinence (P = 0.005). Urinary incontinence was marginally associated with a wider intertuberous diameter (P = 0.017) and pelvic arch (P = 0.017). There were no significant differences in pelvimetry measures between women with and without prolapse (e.g., vaginal or cervical descent to or beyond the hymen). We did not detect meaningful differences in soft tissue dimensions for women with and without these pelvic floor disorders. Dimensions of the bony pelvis do not differ substantially between primiparous women with and without postpartum urinary incontinence, fecal incontinence and prolapse.