Atlas of breast magnetic resonance imaging

Utility of positron emission tomography for determination of axillary metastasis of breast cancer

Objectives

The involvement of axillary lymph nodes plays a key role in breast cancer staging. Positron emission tomography is a promising modality for detecting axillary lymph node metastasis. In addition, nomograms are used to predict the status of axillary lymph nodes. In this study, the role of positron emission tomography in determining axillary metastasis and its correlation with the nomogram was evaluated.

Material and Methods

The axillary maximum standard uptake value (SUVmax) values of the patients in the preoperative period, the features in the perioperative and postoperative specimen and Memorial Sloan Kettering Cancer Center nomogram data were evaluated.

Results

As axillary SUVmax detected by Positron emission tomography in the preoperative period increased, so did the likelihood of lymph node involvement. Axillary SUVmax value were compared with Memorial Sloan Kettering Cancer Center nomogram data but no correlation was found. Age, lymph node number, histopathology results, mass diameter, presence or absence of lymphovascular invasion and/or perineural invasion, tumor type, estrogen receptor status, Ki67 and Cerb-B2 statuses were not correlated. However, axillary SUVmax was inversely correlated with grade and progesterone receptor status.

Conclusion

Results from positron emission tomography of axillary lymph nodes in breasts cancer patients showed that SUVmax was only inversely related to cancer grade and progesterone receptor status while not correlating with other accepted parameters for tumor assessment. Thus there is insufficient reliability for the use of axillary SUVmax alone for accurate assessment of tumor characteristics at present.

Imaging and Management of Fibroepithelial Lesions of the Breast: Radiologic-Pathologic Correlation

Fibroepithelial lesions (FELs) are among the most common breast masses encountered by breast radiologists and pathologists. They encompass a spectrum of benign and malignant lesions, including fibroadenomas (FAs) and phyllodes tumors (PTs). FAs are typically seen in young premenopausal women, with a peak incidence at 20-30 years of age, and have imaging features of oval circumscribed hypoechoic masses. Although some FA variants are especially sensitive to hormonal influences and can exhibit rapid growth (eg, juvenile FA and lactational adenomas), most simple FAs are slow growing and involute after menopause. PTs can be benign, borderline, or malignant and are more common in older women aged 40-50 years. PTs usually manifest as enlarging palpable masses and are associated with a larger size and sometimes with an irregular shape at imaging compared with FAs. Although FA and FA variants are typically managed conservatively unless large and symptomatic, PTs are surgically excised because of the risk of undersampling at percutaneous biopsy and the malignant potential of borderline and malignant PTs. As a result of the overlap in imaging and histologic appearances, FELs can present a diagnostic challenge for the radiologist and pathologist. Radiologists can facilitate accurate diagnosis by supplying adequate tissue sampling and including critical information for the pathologist at the time of biopsy. Understanding the spectrum of FELs can facilitate and guide appropriate radiologic-pathologic correlation and timely diagnosis and management of PTs. Published under a CC BY 4.0 license. Online supplemental material is available for this article. Quiz questions for this article are available through the Online Learning Center.

Radiologic-Pathologic Correlation of Fibroepithelial Lesions: A Pictorial Review

Fibroepithelial lesions (FEL) of the breast encompass a spectrum of masses ranging from benign to malignant. Although these lesions are on the same biologic spectrum, differences in their clinical behaviors necessitate different management approaches. While imaging features are nonspecific, small size (less than 3 cm), oval shape, circumscribed margins, growth in diameter less than 20% in six months, and homogeneous echotexture on US favor fibroadenoma (FA). Conversely, larger size (3 cm or larger), rapid growth, irregular shape, noncircumscribed margins, and heterogeneous echotexture suggest possible phyllodes tumor (PT). Histopathologically, increased stromal cellularity, stromal atypia, and mitotic activity characterize PT, while FA typically lack these features. In this review, we summarize the imaging and pathology characteristics of nonmalignant FEL, including simple, juvenile, and complex FA, and benign and borderline PT and highlight the collaborative role of radiologists and pathologists in informing diagnosis and clinical management.

Optimization of Ultrasound Backscatter Spectroscopy to Assess Neurotoxic Effects of Anesthesia in the Newborn Non-human Primate Brain

Studies in animal models have revealed that long exposures to anesthetics can induce apoptosis in the newborn and young developing brain. These effects have not been confirmed in humans because of the lack of a non-invasive, practical in vivo imaging tool with the ability to detect these changes. Following the successful use of ultrasound backscatter spectroscopy (UBS) to monitor in vivo cell death in breast tumors, we aimed to use UBS to assess the neurotoxicity of the anesthetic sevoflurane (SEVO) in a non-human primate (NHP) model. Sixteen 2- to 7-day-old rhesus macaques were exposed for 5 h to SEVO. Ultrasound scanning was done with a phased array transducer on a clinical ultrasound scanner operated at 10 MHz. Data consisting of 10-15 frames of radiofrequency (RF) echo signals from coronal views of the thalamus were obtained 0.5 and 6.0 h after initiating exposure. The UBS parameter "effective scatterer size" (ESS) was estimated by fitting a scattering form factor (FF) model to the FF measured from RF echo signals. The approach involved analyzing the frequency dependence of the measured FF to characterize scattering sources and selecting the FF model based on a χ² goodness-of-fit criterion. To assess data quality, a rigorous acceptance criterion based on the analysis of prevalence of diffuse scattering (an assumption in the estimation of ESS) was established. ESS changes after exposure to SEVO were compared with changes in a control group of five primates for which ultrasound data were acquired at 0 and 10 min (no apoptosis expected). Over the entire data set, the average measured FF at 0.5 and 6.0 h monotonically decreased with frequency, justifying fitting a single FF over the analysis bandwidth. χ² values of a (inhomogeneous continuum) Gaussian FF model were one-fifth those of the discrete fluid sphere model, suggesting that a continuum scatterer model better represents ultrasound scattering in the young rhesus brain. After application of the data quality criterion, only 5 of 16 subjects from the apoptotic group and 5 of 5 subjects from the control group fulfilled the acceptance criteria. All subjects in the apoptotic group that passed the acceptance criterion exhibited a significant ESS reduction at 6.0 h. These changes (-6.4%, 95% Interquartile Range: -14.3% to -3.3%) were larger than those in the control group (-0.8%, 95% Interquartile Range: -2.0% to 1.5%]). Data with a low prevalence of diffuse scattering corresponded to possibly biased results. Thus, ESS has the potential to detect changes in brain microstructure related to anesthesia-induced apoptosis.

Sonography of Invasive Apocrine Carcinoma of the Breast in Five Cases

OBJECTIVE

To evaluate the sonographic features of invasive apocrine carcinoma (IAC) of the breast.

MATERIALS AND METHODS

This study included five pathologically proven cases of IAC, and their sonographic features were retrospectively analyzed according to the Breast Imaging Reporting and Data System (BI-RADS) lexicon.

RESULTS

All five lesions involved the left breast and were seen as irregularly shaped masses. All lesions, except one, had a parallel orientation to the chest wall. All five lesions showed noncircumscribed margins and heterogeneous echotexture; however, they showed various posterior features. One lesion had edema as an associated feature. Sonographic assessments were classified as BI-RADS category 4 in all five cases.

CONCLUSION

Invasive apocrine carcinoma sonographic findings are difficult to differentiate from those of invasive ductal carcinoma of no special type.

Typical atypical findings on dynamic MRI of the breast

Dynamic contrast enhanced magnetic resonance imaging (DCE MRI) of the breast has become an important tool to detect and characterize breast disease. The American College of Radiology Breast Imaging Reporting and Data System (BI-RADS(®)) provides a standardized vocabulary for describing the morphologic features and contrast kinetics of breast lesions. However, some lesions may show morphologic and dynamic MR features not consistent with their histologic nature resulting in incorrect categorization as malignant or benign. Another cause of diagnostic problems is artifacts. Thus correct interpretation of dynamic MRI of the breast demands knowledge of the most common pitfalls encountered in clinical practice. A pictorial overview of these is presented, with particular reference to the differentiation of malignant tumors from benign lesions.