Yield of MR-directed US for MRI-detected breast findings: how often can we avoid MR biopsy?

PURPOSE: To evaluate the yield of MR-directed ultrasound for MRI detected breast findings. METHODS: This retrospective study included 857 consecutive patients who had a breast MRI between January 2017-December 2020 and received a BI-RADS 4 assessment. Only exams recommended for MR-directed ultrasound were included in the study, yielding 765 patients. Findings were characterized by presence or absence of a sonographic correlate. Utilizing the electronic medical record, for those with a sonographic correlate, the size, location, and morphology were noted. Imaging guided (Ultrasound and MRI) pathology results as well as excisional pathology results were recorded. A multivariable logistical regression analysis was used to investigate the clinical utility of MR-directed ultrasound. RESULTS: There were 1262 MRI-detected BI-RADS category 4 findings in 765 patients. Of the 1262 findings, MR-directed ultrasound was performed on 852 (68 %). Of these, 291/852 (34 %) had an ultrasound correlate, including 143/291 (49 %) benign lesions, 81/291 (28 %) malignant lesions, 16/291 (5 %) with high-risk pathology and 51/291 (18 %) unknown due to lost to follow-up. Of those findings with ultrasound correlates, 173/291 (59 %) represented masses, 69/291 (24 %) were regions of non-mass enhancement, 22/291 (7.6 %) were foci and 27/291 (9.3 %) fell into the category of other which included lymph node, cysts, and scar tissue. Masses were significantly more likely to be identified on MR-directed ultrasound (p < 0.0001) compared to foci. CONCLUSION: The yield of MR-directed ultrasound is significantly higher for masses, than foci and non-mass enhancement, which should be taken into consideration when recommending an MR-directed ultrasound.

A cross-species analysis of systemic mediators of repair and complex tissue regeneration.

Regeneration is an elegant and complex process informed by both local and long-range signals. Many current studies on regeneration are largely limited to investigations of local modulators within a canonical cohort of model organisms. Enhanced genetic tools increasingly enable precise temporal and spatial perturbations within these model regenerators, and these have primarily been applied to cells within the local injury site. Meanwhile, many aspects of broader spatial regulators of regeneration have not yet been examined with the same level of scrutiny. Recent studies have shed important insight into the significant effects of environmental cues and circulating factors on the regenerative process. These observations highlight that consideration of more systemic and possibly more broadly acting cues will also be critical to fully understand complex tissue regeneration. In this review, we explore the ways in which systemic cues and circulating factors affect the initiation of regeneration, the regenerative process, and its outcome. As this is a broad topic, we conceptually divide the factors based on their initial input as either external cues (for example, starvation and light/dark cycle) or internal cues (for example, hormones); however, all of these inputs ultimately lead to internal responses. We consider studies performed in a diverse set of organisms, including vertebrates and invertebrates. Through analysis of systemic mediators of regeneration, we argue that increased investigation of these "systemic factors" could reveal novel insights that may pave the way for a diverse set of therapeutic avenues.