Evaluation of sonographic detectability of different markers within an in vitro simulation model of the axilla.

PURPOSE: Clip-marking of axillary lymph nodes with initial biopsy-confirmed metastasis is required for targeted axillary dissection (TAD), which includes sentinel lymph node dissection (SLND) and selective localization and removal of the clipped targeted lymph node. There have been several studies which examined the feasibility of TAD in routine clinical use. In this context, the optimal clip visualisation was noted as one of the crucial limiting factors. We, therefore, evaluated the sonographic detectability of 10 different commercially available markers within an in vitro model simulating the anatomical composition of the axilla. METHODS: In this standardised model consisting of porcine fat with 30 mm thickness, the visibility of a total of ten markers was analysed in all 3 planes (parallel, diagonal, orthograde) with wire guidance and then classified into either "visibility good", "visibility moderate" or "visibility poor" with regard to the alignment of the transducer. Additionally, "real-life conditions" were simulated, in which the markers were searched without any wires guidance. RESULTS: It was observed that, while not all markers are detectable in fatty tissue, markers with spherical shape (non-embedded Inconel or Nitinol) or rectangular-shaped Titanium markers with embedded material have a clear advantage. 3D-shaped markers can always be detected in all three axes, which is of particular importance in the axilla with its pyramid shape and fatty tissue. CONCLUSION: The shape and the embedding of the material play a crucial role for visibility and efficacy of the marker, as reliable marking of suspicious and pathological axillary lymph nodes is essential for TAD.

Percutaneous Ultrasound-Guided Core Needle Biopsy: Comparison of 16-Gauge versus 14-Gauge Needle and the Effect of Coaxial Guidance in 1065 Breast Biopsies - A Prospective Randomized Clinical Noninferiority Trial.

PURPOSE: Ultrasound-guided core needle biopsy (CNB) is considered the standard assessment to diagnose sonographically visible suspicious breast mass lesions. Based on nonrandomized trials, the current German guidelines recommend at least three cylinders with ≤ 14-gauge needle biopsy. However, no recommendation is made as to how many specimens are needed with a smaller needle size, such as 16-gauge, or if biopsy with coaxial guidance improves diagnostic accuracy and quality. Therefore, in a prospective monocentric unblinded randomized controlled clinical noninferiority trial, the diagnostic accuracy of 16-gauge versus 14-gauge core needle biopsy, with and without coaxial guidance, was evaluated. MATERIALS AND METHODS: 1065 breast biopsies were included in order to analyze the number of core samples necessary to obtain an appropriate rate of diagnostic quality adequate for histological evaluation, and to achieve high diagnostic accuracy and diagnostic yield. Histological results were verified by surgery or long-term follow-up of at least two years up to five years. RESULTS: In order to obtain an additive diagnostic accuracy of > 99 %, a minimum of two cylinders with 14-gauge biopsy were required. The diagnostic accuracy and the diagnostic quality of 14-gauge biopsy were not affected by the coaxial technique. When performing a 16-gauge biopsy, five cylinders were required to achieve an additive diagnostic accuracy of > 99 %. Without coaxial guidance, 16-gauge CNB required at least three samples, whereas five needle passes with coaxial-guided 16-gauge biopsy were needed. CONCLUSION: The diagnostic accuracy and quality of ultrasound-guided 16-gauge core needle biopsy were inferior to the 14-gauge needle size, regardless of the use of a coaxial technique.