Prospective assessment of adjunctive ultrasound-guided diffuse optical tomography in women undergoing breast biopsy: Impact on BI-RADS assessments

Abstract

Purpose: To assess the impact of adjunctive ultrasound guided diffuse optical tomography (US-guided DOT) on BI-RADS assessment in women undergoing US-guided breast biopsy.

Method: This prospective study enrolled women referred for US-guided breast biopsy between 3/5/2019 and 3/19/2020. Participants underwent US-guided DOT immediately before biopsy. The US-guided DOT acquisition generated average maximum total hemoglobin (HbT) spatial maps and quantitative HbT values. Four radiologists blinded to histopathology assessed conventional imaging (CI) to assign a CI BI-RADS assessment and then integrated DOT information in assigning a CI&DOT BI-RADS assessment. HbT was compared between benign and malignant lesions using an ANOVA test and Tukey's test. Benign biopsies were tabulated, deeming BI-RADS ≥ 4A as positive. Reader agreement was assessed.

Results: Among 61 included women (mean age 48 years), biopsy demonstrated 15 (24.6%) malignant and 46 (75.4%) benign lesions. Mean HbT was 55.3 ± 22.6 µM in benign lesions versus 85.4 ± 15.6 µM in cancers (p < .001). HbT threshold of 78.5 µM achieved sensitivity 80% (12/15) and specificity 89% (41/46) for malignancy. Across readers and patients, 197 pairs of CI BI-RADS and CI&DOT BI-RADS assessments were assigned. Adjunctive US-guided DOT achieved a net decrease in 23.5% (31/132) of suspicious (CI BI-RADS ≥ 4A) assessments of benign lesions (34 correct downgrades and 3 incorrect upgrades). 38.3% (31/81) of 4A assessments were appropriately downgraded. No cancer was downgraded to a non-actionable assessment. Interreader agreement analysis demonstrated kappa = 0.48-0.53 for CI BI-RADS and kappa = 0.28-0.44 for CI&DOT BI-RADS.

Conclusions: Integration of US-guided DOT information achieved a 23.5% reduction in suspicious BI-RADS assessments for benign lesions. Larger studies are warranted, with attention to improved reader agreement.

Keywords: Breast cancer; Breast ultrasound; Diffuse optical tomography; Optical imaging; Predictive value.

Fig. 1.

Photographs of the diffuse optical tomography (DOT) probe in the open position with a commercial ultrasound transducer (yellow arrow) in place (A), and in the closed position looking at the probe surface (B). White arrow (B) represents 1 of 9 light emission optical fibers, blue arrowhead (B) represents 1 of 14 light detection optical fibers.

Fig. 2.

Single representative level from spatial maps of average maximum total hemoglobin concentration (HbT) of three different patients highlighting the HbT spatial map features. A. 40-year-old woman with fat necrosis. Spatial map shows background HbT only. B. 50-year-old woman with intermediate grade invasive ductal carcinoma. Spatial map shows high HbT (113 μM), oval shape, central location of highest HbT (arrow), and tight ring distribution (bracket). C. 40-year-old woman with fibroadenomatoid change. Spatial map shows intermediate HbT (72 μM) with “not oval” shape, peripheral location of highest HbT (arrowheads), and diffuse ring distribution (bracket).

Fig. 3.

Flow chart of patient sample. DOT = diffuse optical tomography; US = ultrasound.

Fig. 4.

Anti-radial ultrasound (US) image and average maximum total hemoglobin concentration (HbT) spatial distribution map of a 50-year-old woman (patient 32) with a 1.6 cm stage 1 intermediate grade invasive ductal carcinoma. US shows an irregular hypoechoic mass with indistinct margins (arrow). US-guided diffuse optical tomography (DOT) reveals HbT of 113 μM with oval shape, central high HbT, and tight ring distribution. All three readers upgraded assessment from BI-RADS 4C on conventional imaging (CI) to BI-RADS 5 based on CI and DOT.

Fig. 5.

Radial ultrasound image and average maximum total hemoglobin concentration (HbT) spatial distribution map of a 26-year-old woman (patient 008) with biopsy proven stromal fibrosis. The patient presented with a palpable abnormality corresponding to a sonographic hypoechoic area. Diffuse optical tomography (DOT) revealed HbT of 33.7 μM, below level of < 50 μM that is indicative of benign lesions. Three of four readers downgraded the lesion from a BI-RADs 4A on conventional imaging (CI) to BI-RADS 2 or 3 based on CI and DOT; one reader maintained BI-RADS 4A assessment.