Veterinary Diagnostic Imaging exam questions: topics, study tips and free sample questions

Answer: D. Fluoroscopy is commonly used to diagnose tracheal collapse. Fluoroscopy provides a continuous radiographic image, allowing visualization of the changing tracheal diameter during inspiration and expiration. Fluoroscopy is an excellent tool for assessing dynamic processes and moving structures. Other indications for fluoroscopy include assessment of esophageal motility, myelography, cardiovascular studies, fracture reductions and catheter/stent placement. Because a continuous x-ray beam is used, radiation exposure is a concern. Radiographers must follow safety procedures and wear a dosimeter during procedures.

Answer: B. Acoustic shadowing occurs when ultrasound waves hit dense, highly reflective or sound- absorptive substances like bone, calcium, or uroliths. An acoustic shadow appears as a dark area deep to the dense material because the ultrasound waves cannot reach this tissue. When ultrasound waves hit gas/air in the lungs it causes a reverberation artifact because the ultrasound beam is reflected back to the transducer. Some of this beam bounces off the transducer, reenters the body, and is reflected again. This artifact appears as parallel white lines (a.k.a. echogenic bands) on the ultrasound image. Acoustic enhancement occurs when ultrasound waves pass through fluid-filled structures with low attenuation such as the gallbladder. When the ultrasound wave hits the deep margin of the gallbladder it is bounced back to the transducer with more intensity than the waves that are passing through the surrounding liver. This causes a region of increased echogenicity deep to the fluid-filled structure.