Nonmass Findings at Breast US: Definition, Classifications, and Differential Diagnosis.

A nonmass finding at US has been described as a discrete identifiable area of altered echotexture compared with that of the surrounding breast tissue that does not conform to a mass shape. Recognizing nonmass findings is important because breast cancer can manifest as such lesions, and US correlate findings for mammographic and breast MRI abnormalities may manifest as nonmass findings. The term nonmass finding is not part of the current Breast Imaging Reporting and Data System US terminology, and no standardized approach to classify and evaluate nonmass findings at US currently exists, despite the various classification systems proposed in the literature. There is also considerable overlap between the sonographic features of benign and malignant causes of nonmass findings. These limitations cause diagnostic difficulty in evaluating clinical significance and recommending appropriate management. The authors review the definitions and classification systems of US nonmass findings proposed in the literature and illustrate the sonographic features of nonmass findings to help radiologists identify them at US. A range of benign and malignant causes of nonmass findings are reviewed, and sonographic-histopathologic correlations of nonmass findings are discussed. Cases of breast MRI and mammographic findings that may manifest as US nonmass findings are presented. Radiologists can improve detection and interpretative accuracy, as well as correlation of mammographic and MRI breast lesions, by increasing their recognition and understanding of nonmass findings at US.©RSNA, 2020.

Beyond appendicitis: ultrasound findings of acute bowel pathology.

Bowel pathology is a common unexpected finding on routine abdominal and pelvic ultrasound. However, radiologists are often unfamiliar with the ultrasound appearance of the gastrointestinal tract due to the underutilization of ultrasound for bowel evaluation in the USA. The purpose of this article is to familiarize radiologists with the characteristic ultrasound features of a variety of bowel pathologies. Basic ultrasound technique for bowel evaluation, ultrasound appearance of normal bowel, and key ultrasound features of common acute bowel abnormalities will be reviewed.

Imaging of Acute Conditions of the Perineum.

A wide range of acute conditions can affect the perineum, from self-limited disease to conditions that are potentially life threatening or contribute to substantial patient morbidity if not promptly diagnosed and appropriately treated. Imaging is essential in the clinical management of perineal disease because it allows accurate anatomic localization of the origin and extent of the disease to be determined. Familiarity with complex perineal anatomy, appropriate use of imaging modalities, and the spectrum of imaging findings seen in acute perineal conditions is crucial for radiologists to make a rapid and accurate diagnosis. Various imaging modalities are available to evaluate acute perineal conditions, each with their own advantages and disadvantages. Computed tomography is used most commonly in the acute care setting because of its widespread availability and rapid image acquisition. Ultrasonography could be used to evaluate superficial and palpable abnormalities and is especially helpful for diagnosis of genital injuries. Magnetic resonance (MR) imaging exhibits superior tissue contrast resolution, provides excellent characterization of conditions, and lacks ionizing radiation. Its role is increasing in the acute care setting; however, MR imaging is not always readily available and is currently reserved for use as a problem-solving technique. Retrograde urethrography is the modality of choice for evaluating traumatic urethral injury. ©RSNA, 2018.