MRI-guided breast interventions

Abstract

APPLIED RADIOLOGY © n 7 October 2015 7 n APPLIED RADIOLOGY © w .appliedradiol gy.com October 2015 Breast MRI has been well established as the most sensitive modality in breast imaging.1 However, it suffers from limited specificity, with known overlap between the signal intensity and enhancement characteristics of benign and malignant abnormalities, often requiring tissue sampling for definitive diagnosis.2 Second-look sonography is defined as a targeted ultrasound examination that uses lesion features such as size, morphology and location gathered from the concurrent MRI examination to evaluate for a correlative ultrasound lesion. If the MRI-detected lesion can be seen with targeted sonography, biopsy can be performed under ultrasound guidance.3, 4 Although the likelihood of a lesion being malignant has been shown to be higher if it demonstrates a sonographic correlate, reported lesion-detection rates with second-look sonography vary in the literature.5,6 It is important to remember that the lack of a sonographic correlate does not exclude malignancy.6 According to the American College of Radiology (ACR) practice guidelines, MRI-guided breast biopsy is warranted for suspicious lesions, or lesions highly suggestive of malignancy (BI-RADS 4 and 5) that are mammographically and sonographically occult or seen with certainty only on breast MRI. MRI-guided biopsy offers a minimally invasive alternative to surgical excision or open surgical biopsy. Other advantages include reduced morbidity, better cosmetic results and decreased scarring, with comparable accuracy. In addition, percutaneous biopsies are more cost effective, with less time lost from the patient’s normal activities.7 MRI-guided needle localizations provide safe and technically feasible presurgical needle localization, particularly in cases where disease extent is either not demonstrated or larger than demonstrated by sonography and mammography, and in cases of biopsy marking clip migration or lack of clip deployment at MRI-guided biopsy. If a lesion is not technically amenable to MRI-guided breast interventions