Category assessment based on 3D volume data acquired by automated breast ultrasonography

1000-Case Reader Study of Radiologists' Performance in Interpretation of Automated Breast Volume Scanner Images with a Computer-Aided Detection System

The objective of our study was to assess, in a reader study, radiologists' performance in interpretation of automated breast volume scanner (ABVS) images with the aid of a computer-aided detection (CADe) system. Our study is a retrospective observer study with the purpose of investigating the effectiveness of using a CADe system as an aid for radiologists in interpretation of ABVS images. The multiple-reader, multiple-case study was designed to compare the diagnostic performance of radiologists with and without CADe. The study included 1000 cases selected from ABVS examinations in our institution in 2012. Among those cases were 206 malignant, 486 benign and 308 normal cases. The cancer cases were consecutive; the benign and normal cases were randomly selected. All malignant and benign cases were confirmed by biopsy or surgery, and normal cases were confirmed by 2-y follow-up. Reader performance was compared in terms of area under the receiver operating characteristic curve, sensitivity and specificity. Additionally, the reading time per case for each reader was recorded. Nine radiologists from our institution participated in the study. Three had more than 8 y of ultrasound experience and more than 4 y of ABVS experience (group A); 3 had more than 5 y of ultrasound experience (group B), and 3 had more than 1 y of ultrasound experience (group C). Both group B and group C had no ABVS experience. The CADe system used was the QVCAD System (QView Medical, Inc., Los Altos, CA, USA). It is designed to aid radiologists in searching for suspicious areas in ABVS images. CADe results are presented to the reader simultaneously with the ABVS images; that is, the radiologists read the ABVS images concurrently with the CADe results. The cases were randomly assigned for each reader into two equal-size groups, 1 and 2. Initially the readers read their group 1 cases with the aid of CADe and their group 2 cases without CADe. After a 1-mo washout period, they re-read their group 1 cases without CADe and their group 2 cases with CADe. The areas under the receiver operating characteristic curves of all readers were 0.784 for reading with CADe and 0.747 without CADe. Areas under the curves with and without CADe were 0.833 and 0.829 for group A, 0.757 and 0.696 for group B and 0.759 and 0.718 for group C. All differences in areas under the curve were statistically significant (p <0.05), except that for group A. The average reading time was 9.3% (p < < 0.05) faster with CADe for all readers. In summary, CADe improves radiologist performance with respect to both accuracy and reading time for the detection of breast cancer using the ABVS, with the greater benefit for those inexperienced with ABVS.

Ultrasound Imaging Technologies for Breast Cancer Detection and Management: A Review

Ultrasound imaging is a commonly used modality for breast cancer detection and diagnosis. In this review, we summarize ultrasound imaging technologies and their clinical applications for the management of breast cancer patients. The technologies include ultrasound elastography, contrast-enhanced ultrasound, 3-D ultrasound, automatic breast ultrasound and computer-aided detection of breast ultrasound. We summarize the study results seen in the literature and discuss their future directions. We also provide a review of ultrasound-guided, breast biopsy and the fusion of ultrasound with other imaging modalities, especially magnetic resonance imaging (MRI). For comparison, we also discuss the diagnostic performance of mammography, MRI, positron emission tomography and computed tomography for breast cancer diagnosis at the end of this review. New ultrasound imaging techniques, ultrasound-guided biopsy and the fusion of ultrasound with other modalities provide important tools for the management of breast patients.

Comparison of automated breast ultrasonography to handheld ultrasonography in detecting and diagnosing breast lesions

BACKGROUND

Automated breast ultrasonography (ABUS) is increasingly used as a screening tool. Several studies have demonstrated a similar diagnostic performance for ABUS compared with handheld ultrasonography (HHUS), but the overall results have been controversial.

PURPOSE

To compare the clinical utility of ABUS and HHUS for detection and diagnosis of breast lesions.

MATERIAL AND METHODS

ABUS and HHUS images of suspicious breast lesions were obtained for 173 consecutive women scheduled to undergo ultrasonography (US)-guided or stereotactic biopsy. There were a total of 206 lesions, 46 of which were malignant and 160 benign. Three breast radiologists took part in this study: two reviewed the ABUS images, and the third reviewed all of the images, ABUS and HHUS, as well as the patients' medical records. The biopsied-lesion-detection rates were obtained. Using the Breast Imaging Reporting and Data System (BI-RADS), the images of the biopsied lesions were evaluated. Factors affecting ABUS detectability were analyzed.

RESULTS

The overall detection rates were 83.0% for ABUS and 94.2% for HHUS. Ten lesions were not detected on either HHUS or ABUS and these were microcalcifications (one malignancy and nine benign lesions). Of the 194 HHUS-detected lesions, 169 were detected by ABUS and 25 benign were not. ABUS less frequently detected lesions of smaller size as well as those of benign appearance and lower final-assessment category (P = 0.011 and P < 0.0001, respectively).

CONCLUSION

ABUS detected all of the malignant lesions that were detected on HHUS. ABUS missed several smaller benign lesions.

The clinical utility of automated breast volume scanner: a pilot study of 139 cases

PURPOSE

The aim of this study is to evaluate the clinical utility of automated breast volume scanner (ABVS) for detecting and diagnosing the breast lesions.

METHODS

From December 2010 to January 2012, bilateral whole breast examinations were performed with ABVS for 139 women. Based on the Breast Imaging Reporting and Data System (BI-RADS) categories, the breast lesions were evaluated on coronal multiplanar reconstruction images using the ABVS workstation. Then, the imaging results were compared with those on conventional handheld ultrasound (HHUS) images. Histological diagnoses were performed on BI-RADS category 4 and 5 lesions.

RESULTS

A total of 453 lesions were detected by ABVS. On the HHUS, 33 new lesions were detected but 69 lesions were not detected. BI-RADS category 2 and 3 matched to those on ABVS at 73.5% (61/83) and 85.4% (276/323). In 47 lesions of BI-RADS category 4 or 5, there was an exact match to those on ABVS. In addition, 47 lesions were classified as BI-RADS category 4 and 5, for which an ultrasound-guided core needle biopsy was performed. The malignant lesions of BI-RADS category 4 and 5 showed the following: 2/27 (7.4%) in 4A, 4/5 (80%) in 4B, 2/2 (100%) in 4C, and 13/13 (100%) in 5. The ABVS showed 21 true positives and a positive predictive value of 44.7% (21/47).

CONCLUSION

There was considerable agreement in the assessment of the breast lesions by ABVS and HHUS. The ABVS had advantages of high diagnostic accuracy, examiner-independence, multislice visualization of the whole breast and less time-consuming. Our results indicate that ABVS might be a useful modality in diagnosing breast lesions.