RDMS Abdomen study guide
RDMS Abdomen · Work through your exam, one topic at a time.
RDMS Abdomen (AB) is the specialty examination that, together with the Sonography Principles and Instrumentation (SPI) exam, qualifies a sonographer for Registered Diagnostic Medical Sonographer (RDMS) certification. ARDMS administers it, and it is built for sonographers who perform abdominal ultrasound - evaluating the soft tissues, blood vessels, and organs of the human abdomen - and who want a credential that hospitals, imaging centers, and specialty practices recognize. The RDMS Abdomen study guide has 8 sections and about 2,098 words.
01Basic Abdominal Anatomy
The sonographic map of the abdomen rests on a few fixed relationships. The liver is divided into eight Couinaud segments by portal vein branches and drained by three hepatic veins.
338 words, about 2 min02Perfusion and Function
The liver has a dual supply: the portal vein delivers roughly 75% of flow, but the hepatic artery supplies about half the oxygen. The hepatic arterial buffer response compensates for falling portal flow by dilating the hepatic artery.
284 words, about 1 min03Pathology
Focal liver lesions: hemangioma is well defined and hyperechoic with posterior enhancement and no internal Doppler flow; focal nodular hyperplasia is near-isoechoic with a central scar and spoke-wheel vascularity; hepatocellular carcinoma in a cirrhotic liver shows arterial hyperenhancement with portal-venous or late washout on contrast-enhanced ultrasound; metastases are often multiple and target-like. Diffuse disease: cirrhosis produces a coarse nodular surface, caudate hypertrophy, right-lobe atrophy, and signs of portal hypertension; steatosis brightens the liver, degrades deep penetration, and blurs vessel walls.
273 words, about 1 min04Vascular Abnormalities
Abdominal aortic aneurysm: measure outer wall to outer wall, perpendicular to the vessel, in the anteroposterior plane; mural thrombus is included in the diameter. A diameter of 3.0 cm or more defines an aneurysm.
254 words, about 1 min05Trauma
The FAST examination screens for free fluid in four windows: perihepatic (Morison's pouch), perisplenic, pelvic (rectovesical or pouch of Douglas), and subxiphoid pericardial; an extended FAST adds thoracic views. Free fluid appears as an anechoic stripe, though acute hemorrhage may be echogenic and complex.
218 words, about 1 min06Postoperative Anatomy
Postoperative anatomy changes normal landmarks. After cholecystectomy the gallbladder is absent, surgical clips mark the fossa, and a small fluid collection may be normal; a bile leak or abscess is a complication.
234 words, about 1 min07Abdominal Physics
Frequency governs the trade-off between resolution and penetration: higher frequencies improve axial and lateral resolution but attenuate faster. Axial resolution equals half the spatial pulse length, and wavelength in soft tissue (mm) is approximately 1.54 divided by frequency in MHz, so 5 MHz gives about 0.31 mm.
266 words, about 1 min08Clinical Care and Practice
Patient preparation: fasting for 6–8 hours is standard for gallbladder, biliary, and pancreatic examinations, while pelvic scans require a full bladder. Positioning-supine, left lateral decubitus, semi-erect, or standing-can move stones and improve gallbladder visualization.
231 words, about 1 min