Acute Cholecystitis. Longitudinal image of a gallbladder demonstrating gallstone, biliary sludging, and pericholecystic fluid. (Ultrasound contributor: Jeremy S. Boyd, MD.)
EMERGENCY ULTRASOUND: INTRODUCTION
Emergency ultrasound (EUS) is the use of point-of-care ultrasound by clinicians in the emergency department (ED) to answer focused clinical questions and/or assist in performing invasive procedures. It is not an extension of the physical exam by means of advanced technology, but rather uses ultrasound technology to sonographically assess patients for the presence or absence of pathologic conditions that commonly present to the ED. The use and scope of EUS has grown and evolved since the FAST exam was first introduced as part of the evaluation of the trauma patient. For more than a decade, EUS has been a required component of Emergency Medicine Residency training with additional training offered as part of a dedicated EUS fellowship programs. These dedicated EUS fellowship training programs have surged in recent years to meet the demand, with over 90 such programs currently operating.
EUS can be used by clinicians across the spectrum of diseases that present to the ED. Properly trained emergency clinicians use ultrasound to answer focused questions regarding the patient’s presenting complaint or condition. Rather than a comprehensive approach, the EUS examination is goal-directed and focused, often seeking to answer dichotomous, “yes/no,” questions such as “Is there fluid within the peritoneum?”
This text is not intended to provide an in-depth description of the limitations, efficacy, sensitivity, or appropriateness of EUS. Every application described herein is intended as a rapid visual review for those trained in basic EUS applications. Applicable protocols are based on the imaging guidelines of the American College of Emergency Physicians and American Institute of Ultrasound in Medicine (AIUM), as well as the authors’ collective experience. Basic information—transducer recommendations, scanning protocols, anatomic schematics—is presented within each application to represent both image acquisition and normal and pathological findings.
Sonographic windows—Anatomical locations on the body where an ultrasound probe is placed in order to view internal organs.
Transducer indicator/probe marker/marker dot—Usually a bump or ridge on the ultrasound transducer that corresponds to a symbol on the ultrasound screen. Used to indicate which side of the image corresponds with the transducer’s edge (Fig. 24.1).
Foot print—The part of the ultrasound probe that contacts the patient’s skin (Fig. 24.1).
Hyperechoic/echogenic—Used to describe objects on the ultrasound screen that are bright and therefore reflect sound waves.
Hypoechoic/anechoic—Used to describe objects on the ultrasound screen that are dark and therefore transmit sound waves.
Echotexture—The characteristic appearance of specific organs when viewed using ultrasound. The liver has a characteristic echotexture.
Transducer movements—When performing sonography, specific terms are used to describe characteristic movements of the transducer used to obtain the image desired. Some examples of this include ...