Diagnostic ultrasound ( PDFDrive )

774 PART III Small Parts, Carotid Artery, and Peripheral Vessel Sonography
TABLE 21.1 Breast Imaging Reporting and Data System (BI-RADS) Categories 43
BI-RADS
Category
Description and Examples
Risk of
Malignancy
Recommended Follow-Up
0 Incomplete examination; additional imaging is necessary
to evaluate the inding or area of clinical concern
1 Sonographically normal tissues that cause mammographic
or clinical abnormalities
2 Benign entities: includes intramammary lymph nodes,
ectatic ducts, all simple and some complicated cysts
(milk of calcium), and deinitively benign solid nodules,
such as lipomas and hamartomas
3 “Probably benign” complicated and complex cystic and
solid masses, some small intraductal masses possibly
representing debris or papilloma, and a subset of
ibroadenomas
0% Routine screening a
0% Routine screening a
≤2% Short-interval follow-up
recommendation with either
mammography or ultrasound,
typically 6 months a
4a Mildly suspicious >2-10% Histologic sampling either with
4b Moderately suspicious >10%-≤50%
4c Highly suspicious >50%-<95%
5 Very highly suspicious ≥95%
6 Known malignancy
percutaneous biopsy or
surgical excision
a In the above BI-RADS description, should the patient have a palpable abnormality or other clinical inding and be rated as BI-RADS 1 or 2, the
patient should also have a clinical follow-up in 6 weeks to 3 months to ensure that the clinical inding has not changed. If BI-RADS 3
characterization is associated with a stable lesion at irst follow-up, then an additional 6-month follow-up is recommended. After 1 year of
stability, an additional 1 year, and possibly 2 years, of imaging follow-up may be performed.
been increasingly used to better identify masses associated with
neovascularity that more likely represent malignancy. 35-40 Additional
studies have evaluated whether contrast-enhanced
ultrasound can identify sentinel lymph nodes during the preoperative
evaluation 41 and tumor response to chemotherapy. 42
REPORTING
he ACR Breast Imaging Reporting and Data System (BI-
RADS) was initially developed for mammography but has similar
categories and descriptors for ultrasound 18 to standardize reporting
and data. BI-RADS has developed a standardized lexicon for
describing indings seen on ultrasound in addition to a system
for classifying these indings and their probability of malignancy. 17
he BI-RADS assessment categories for classiication of indings
range from BI-RADS 0 through BI-RADS 6 (Table 21.1).
SONOGRAPHIC FINDINGS
When evaluating the breast by ultrasound, it is important to
adhere to the BI-RADS descriptors of sonographic indings
because they provide a standard lexicon for communicating
results. In this section, we review common imaging indings and
how to describe them according to the most recent edition of
the ACR BI-RADS Atlas. 18
he sonographic indings that correlate with mammographic
abnormalities or areas of clinical concern can fall into several
diferent categories: (1) ANDIs, (2) cysts, (3) solid masses, and
(4) indeterminate (cystic vs. solid) lesions.
Normal Tissues and Variations
Normal breast tissues and variations of normal tissues, including
duct ectasia, FCC, and benign proliferative disorders, can cause
both mammographic and sonographic abnormalities. hese
changes have been termed “ANDIs” (aberrations of normal
development and involution). ANDIs can appear sonographically
not only as normal tissues but as cysts and solid nodules, accounting
for some false-positive results at biopsy. Most sonographically
normal tissues can be characterized as BI-RADS 1. hat being
said, ANDIs can cause a spectrum of abnormalities that can be
characterized as BI-RADS 2, 3, or 4. 44
Cysts and Cystic Masses
Simple Cysts
Simple cysts are anechoic, round or oval, and surrounded
completely by a thin, echogenic wall or capsule with enhanced
sound transmission and thin-edge shadows (Fig. 21.20, Video
21.3). hey form from dilation of the acini in the TDLU. When
multiple acini dilate, they can form a group of small microcysts.
hey can then coalesce together to form a solitary cyst. Cysts
that meet strict criteria for being simple are “deinitively benign”
and do not require further follow-up. Aspiration of simple cysts
is generally reserved for relief of pain and tenderness in very
tense simple cysts.
Demonstrating that a benign simple cyst causes a palpable
lump or mammographic nodule is by far the most valuable inding
demonstrable on sonography because the negative predictive
value is 100%. 45