Fluoroscopy and Special Procedures Flashcards

During a hysterosalpingography (HSG), what type of contrast medium is typically used?

Answer: Water-soluble iodinated contrast

Water-soluble iodinated contrast is used for HSG because it is absorbed by the peritoneum without residual effect if tubal patency allows spillage into the peritoneal cavity.

What serious complication can result from accidental introduction of air into the venous circulation during an IV contrast injection?

Answer: Venous air embolism

Venous air embolism occurs when air enters the venous system and obstructs pulmonary blood flow, which can be life-threatening and requires immediate positioning in the left lateral decubitus (Durant maneuver) position.

Which projection during a barium enema best demonstrates the sigmoid colon in its entirety with minimal overlap?

Answer: LPO or RPO oblique projection

The LPO or RPO oblique projections rotate the pelvis to uncoil the redundant sigmoid loop and project it away from overlapping loops, providing a clear view of the sigmoid colon.

What is the primary purpose of the 'last image hold' (LIH) feature available on modern fluoroscopic equipment?

Answer: To display the last acquired fluoroscopic frame so the radiologist can study it without continuing radiation exposure

Last image hold retains and displays the final fluoroscopic frame on the monitor, allowing the operator to evaluate positioning and anatomy without maintaining continuous radiation exposure.

During an upper GI double-contrast examination, what is the primary advantage of the double-contrast technique over single-contrast?

Answer: It provides superior mucosal detail enabling detection of small lesions

Double contrast (high-density barium coating + gas distension) outlines the mucosal surface in fine detail, making small polyps, ulcers, and early gastric carcinoma visible that may be missed on single-contrast studies.

What is the pharmacological role of glucagon when administered during a GI fluoroscopic examination?

Answer: It produces hypotonic duodenography by temporarily relaxing smooth muscle

Glucagon is an antispasmodic agent that temporarily inhibits smooth muscle contraction, reducing peristalsis and allowing better mucosal coating and visualization during hypotonic studies.

During a voiding cystourethrogram (VCUG), what critical action is the patient asked to perform at the key phase of the examination?

Answer: Actively void (urinate) while images are obtained

The patient voids (urinates) while fluoroscopic images are obtained to evaluate the urethra, bladder neck function, and detect vesicoureteral reflux during the voiding phase.