Stereotactic biopsy with contrast-enhanced mammography: the initial Australian experience.

INTRODUCTION: Contrast-enhanced mammography (CEM) and MRI detect 'contrast-only' lesions (COLs) occult on standard breast imaging (ultrasound and conventional mammography). Until recently, MRI was the only reliable method of biopsy. This study presents the first Australian experience with CEM-guided biopsy (CEMBx) and the lessons learnt. METHODS: A prospective audit of the first 15 consecutive patients who underwent CEMBx for COLs was performed. Indications for contrast imaging, patient and lesion characteristics, procedural details, radiation dose and pathology data were collected. RESULTS: The 15 women were aged 37-81 years (mean 59 years). Indications for contrast imaging were problem solving (n = 3), moderate risk screening (n = 2), cancer staging (n = 9) and symptoms (n = 1). The COLs were non-mass (n = 14), mass (n = 1) and an enhancing asymmetry (n = 1). For one patient, two lesions were sampled during the same event. All lesions enhanced and were successfully sampled followed by marker clip insertion. Most biopsies (87.5%) were performed with the breast in cranio-caudal compression using a horizontal approach. Procedural duration ranged from 13 to 33 min (mean 22 min). Radiation dose was similar to standard stereotactic biopsy. Post-biopsy hematomas occurred in three patients, none required intervention. Clip displacement occurred in three cases. Core biopsy histopathology results were benign (n = 8), malignant (n = 7) and a borderline breast lesion (BBL) (n = 1). Patient satisfaction rates were high. Imaging follow-up is ongoing. CONCLUSIONS: CEMBx is a quick, safe and reliable alternative to MRIBx to sample COLs.

Localisation accuracy with iodine-125 seed versus wire guidance for breast cancer surgery.

INTRODUCTION: Impalpable breast lesions generally require image-guided localisation for breast-conserving surgery. A standard technique is to place a hook wire (HW) within the lesion. Radioguided occult lesion localisation using iodine seeds (ROLLIS) involves inserting a 4.5 mm iodine-125 seed (seed) into the lesion. We hypothesised that a seed could be more precisely positioned in relation to the lesion than a HW and that this may be associated with a lower re-excision rate. METHODS: Retrospective review of consecutive participant data from three ROLLIS RCT (ACTRN12613000655741) sites. Participants underwent preoperative lesion localisation (PLL) with seed or HW between September 2013 and December 2017. Lesion and procedural characteristics were recorded. Distances between (1) any part of the seed or thickened segment of the HW ('TSHW') and the lesion/clip ('distance to device' DTD) and (2) centre of the TSHW/seed and centre of the lesion/clip (device centre to target centre 'DCTC') were measured on immediate postinsertion mammograms. Pathological margin involvement and re-excision rates were compared. RESULTS: A total of 390 lesions (190 ROLLIS and 200 HWL) were analysed. Lesion characteristics and guidance modality used were similar between groups. Ultrasound-guided DTD and DCTC for seed were smaller than for HW (77.1% and 60.6%, respectively, P-value < 0.001). Stereotactic-guided DCTC for seeds was 41.6% smaller than for HW (P-value = 0.001). No statistically significant difference in the re-excision rates was found. CONCLUSION: Iodine-125 seeds can be more precisely positioned for preoperative lesion localisation than HW, however, no statistically significant difference in re-excision rates was detected.

Vacuum-assisted excision biopsy for definitive diagnosis of breast lesions of uncertain malignant potential (B3 lesions) on core biopsy - A single centre Western Australian experience.

INTRODUCTION: In Australia, the usual approach to breast lesions where core biopsy returns an uncertain result ("B3" breast lesion) is to perform surgical diagnostic open biopsy (DOB). This is associated with patient time off work, costs of hospital admission, risks of general anaesthesia and surgical complications. The majority of B3 lesions return benign results following surgery. Vacuum assisted excision biopsy (VAEB) is a less invasive, lower cost alternative, and is standard of care for selected B3 lesions in the United Kingdom. Similar use of VAEB in Australia, could save many women unnecessary surgery. The aim of this study was to document our experience during the introduction of VAEB as an alternative to DOB for diagnosis of selected B3 lesions. METHODS: The multidisciplinary team developed an agreed VAEB pathway for selected B3 lesions. Technically accessible papillary lesions, mucocele-like lesions and radial scars without atypia measuring ≤ 15mm were selected. RESULTS: Over a 7 month period, 18 women with 20 B3 lesions were offered VAEB. 16 women (18 lesions) chose VAEB over DOB. Papillomas were the commonest lesion type. All lesions were successfully sampled: 17/18 were benign. One lesion (6%) was upgraded to malignancy (ductal carcinoma in situ on VAEB, invasive ductal carcinoma at surgery). No major complications occurred. Patient satisfaction was high: 15/16 respondents would again choose VAEB over surgery. CONCLUSION: VAEB is a patient-preferred, safe, well-tolerated, lower-cost alternative to DOB for definitive diagnosis of selected B3 breast lesions.

An atypically located pleomorphic adenoma: Radiological and pathological correlation.

Pleomorphic adenoma is a common benign salivary gland neoplasm which very rarely occurs in the breast. Its radiologic and pathologic appearance may be mistaken for other benign or malignant lesions such as a fibroadenoma or invasive ductal carcinoma. Due to the risk of local recurrence and, rarely, malignant transformation, wide local excision with clear margins is recommended. As such, a correct diagnosis of this lesion is important to ensure appropriate surgical treatment. We report a case of an atypically located pleomorphic adenoma with radiologic-pathologic correlation in an asymptomatic 63-year-old woman.

Artifacts in contrast-enhanced mammography: are there differences between vendors?

PURPOSE: Contrast-Enhanced Mammography (CEM) produces a dual-energy subtracted (DES) image that demonstrates iodine uptake (neovascularity) in breast tissue. We aim to review a range of artifacts on DES images produced using equipment from two different vendors and compare their incidence and subjective severity. METHODS: We retrospectively reviewed CEM studies performed between September 2013 and March 2017 using GE Senographe Essential (n = 100) and Hologic Selenia Dimensions (n = 100) equipment. Artifacts were categorized and graded in severity by a subspecialist breast radiologist and one of two medical imaging technologists in consensus. The incidence of artifacts between vendors was compared by calculating the relative risk, and the severity gradings were compared using a Wilcoxon rank-sum test. RESULTS: Elephant rind, corrugations and the black line on chest wall artifact were seen exclusively in Hologic images. Artifacts such as cloudy fat, negative rim around lesion and white line on pectoral muscle were seen in significantly more Hologic images (p < 0.05) whilst halo, ripple, skin line enhancement, black line on pectoral muscle, bright pectorals, chest wall high-lighting and air gap were seen in significantly more GE images (p < 0.05). The severity gradings for cloudy fat had a significantly higher mean rank in Hologic images (p < 0.001) whilst halo and ripple artifacts had a significantly higher mean rank in GE images (p < 0.001 and p = 0.028 respectively). CONCLUSION: The type, incidence and subjective severity of CEM-specific artifacts differ between vendors. Further research is needed, but differences in algorithms used to produce the DE image are postulated to be a significant contributor.

A comparison of stereotactic and tomosynthesis-guided localisation of impalpable breast lesions.

INTRODUCTION: Impalpable breast cancers require precise pre-operative lesion localisation to minimise re-excision rates. Conventional techniques include hookwire insertion using stereotactic guidance. Newer techniques include the use of tomosynthesis guidance and the use of iodine-125 seeds. This study compares the accuracy of lesion localisation with hookwire or seed insertion using prone stereotactic or upright tomosynthesis guidance. METHODS: This registered quality improvement activity did not require formal ethics approval. The post-localisation images for 116 lesions were reviewed. The distance from the lesion or breast biopsy marker to the hookwire or seed was measured on post-insertion mammograms. The relative placement accuracy of hookwire or seed using prone stereotactic or upright tomosynthesis guidance was compared. A lesion to seed or wire distance > 10 mm was considered technically unsatisfactory. RESULTS: 94.8% of the seeds and wires inserted via prone stereotactic guidance were accurately placed, compared with 89.6% of those inserted via upright tomosynthesis. There were twice as many technically unsatisfactory insertions under upright tomosynthesis guidance. The majority of the unsatisfactory insertions using upright tomosynthesis occurred when the lesion was at or below the level of the nipple and the insertion was performed craniocaudally. CONCLUSION: The degree of accuracy of pre-operative localisation of impalpable breast lesions is significantly higher with the use of prone stereotactic rather than upright tomosynthesis guidance. This was most evident with the placement of I-125 seeds, and in cases where the target lesion was located below the level of the nipple.

Radiographer technique: Does it contribute to the question of clip migration?

INTRODUCTION: Marker clips are commonly deployed at the site of a percutaneous breast biopsy. Studies have shown that displacement of the clip from the site of deployment is not uncommon. The objective of this study was to determine how much 'migration' could be seen with fixed structures within the breast tissue across three consecutive annual screening examinations, and therefore attempt to quantify how much of the reported clip migration could be due to radiographer technique. METHODS: Large, easily identified benign calcifications were measured by two investigators across three consecutive cycles of screening mammography. The position of the calcifications on the two standard mammographic views was measured in two planes. Other variables recorded included breast size and density, compression force used, and location of the benign calcifications within the breast. RESULTS: In 38% of cases, benign breast calcifications showed a mimicked movement of >15 mm in at least one plane. This was greatest in large breasts, those where fibroglandular tissue occupied less than 50% of the breast volume, and in the upper outer quadrant of the breast where mimicked movement >10 mm was noted in up to 90% of the larger breasts. CONCLUSION: Fixed immobile objects in the breast can appear to move a distance of >15 mm in up to 30% of cases. Clinically, some of what has previously been called marker 'migration' may be spurious and accounted for by differences in radiographic positioning techniques.