Can unenhanced breast MRI be used to decrease negative biopsy rates?

Abstract

T he Breast Imaging Reporting and Data Systems (BI-RADS) lexicon (1) of AmericanCollege of Radiology (ACR) provides an efficient and standardized assessment and management of breast lesions. It also stratifies breast cancer risk for a given lesion by classifying them into categories 1 through 5 according to the degree of suspicion.According to this system, solid masses with a circumscribed margin, oval shape (including those with two or three gentle lobulations) and parallel orientation on ultrasonography (US) exam are classified as BI-RADS 3. These types of masses are commonly seen at diagnostic and screening examinations. In this category malignancy is highly unlikely (less than 2%) and a short interval follow-up is recommended (1). However, up to one-third of such masses undergo biopsy mainly because of radiologist, referring clinician, or patient concern about the substantial risk of malignancy (2-4). Many BI-RADS 3 masses are traditionally referred for biopsy if they are palpable, large in size, patient is of advanced age or has a positive family history for breast cancer.The BI-RADS 4 assessment is reserved for findings that do not have the classic appearance of malignancy but are sufficiently suspicious to justify a recommendation for biopsy. This category is largely indeterminate and highly variable in outcome. Breast lesions in this category carry 2% to 95% risk for malignancy (1). Thus, almost all recommendations for breast biopsies come from assessments made using this category. According to BI-RADS classification; category 4 is subgrouped as 4A, 4B, and 4C to better inform the clinicians, pathologists, and patients of the degree of concern. However, the criteria for distinguishing among these subcategories have not been well delineated. BI-RADS 4A designates lesions with a low suspicion for malignancy. In this group, a benign pathologic diagnosis is expected and considered concordant (1). Studies of several institutions by the use of their internal criteria revealed positive predictive value (PPV) of 7%-9% for 4A lesions, and more than 50% of the suspicious lesions fall into this category. On the other hand, BI-RADS 4B and 4C 287From the Department of Radiology (S.K.  sibel_ozy@ yahoo.com) Karadeniz Technical University, School of Medicine, Trabzon, Turkey. BREAST IMAGING ORIGINAL ARTICLE PURPOSE We aimed to determine whether low-risk breast masses can be effectively managed with unenhanced magnetic resonance imaging (MRI) combining T2-weighted sequences with diffusion-weighted imaging (DWI) instead of immediate biopsy to decrease negative biopsy rates. METHODSAfter institutional review board and patient approvals, 141 consecutive women with 156 low-risk breast masses, who underwent unenhanced MRI and later on received a final diagnosis, were included in the study. There were 72 BI-RADS 3 masses in women with relative risk factors and 84 BI-RADS 4A masses, all referred for biopsy. Apparent diffusion coefficient (ADC) cutoff was 0.90×10-3 mm2/s. According to ADC values and T2-weighted imaging charact...

Assessment of breast mass morphology with diffusion‐weighted MRI: Beyond apparent diffusion coefficient

“…On the other hand, abbreviated breast MRI protocols have gained significant popularity due to their shorter acquisition time, lower cost, and comparable diagnostic accuracy to DCE‐MRI . However, there are some recent concerns about nephrogenic systemic fibrosis and gadolinium deposition in neural tissues, which provoked the search for noncontrast‐enhanced breast MRI protocols . The results of those and our present study show that DWI is highly effective in the detection and characterization of breast tumors, and it may be potentially used as an abbreviated MRI for screening or even for some diagnostic purposes.…”

“…It has been presumed that DWI does not allow the assessment of morphological features of breast masses. To assess morphology, contrast‐enhanced T 1 and/or T 2 ‐weighted images are added to DWI in study protocols . However, we obtained substantially high‐moderate consistency between DWI and DCE‐MRI for morphologic parameters and this consistency was better for larger masses.…”

“…In the literature, 78–94% sensitivity and 79–94% specificity were reported for unenhanced MRI combining DWI with T 1 and/or T 2 ‐weighted sequences . On the other hand, 89–91% sensitivity and 91–94% specificity were reported for contrast‐enhanced abbreviated MRI .…”

“…It is noninvasive, has a short scanning time, and is highly specific. There are new promising studies on the use of DWI as a part of the enhanced or unenhanced abbreviated breast MRI protocols . Tumor characterization was performed mainly by apparent diffusion coefficient (ADC) values on DWI.…”

“…I n recent years, noncontrast-enhanced and abbreviated breast magnetic resonance imaging (MRI) methods have gained great interest. [1][2][3][4] Diffusion-weighted imaging (DWI) is a popular, noncontrast-enhanced MRI technique. It measures the random Brownian motion of water molecules in the tissue.…”