Advantages and disadvantages of a plain X ray versus a CT scan?
A plain abdominal radiograph is a low-cost procedure that is easy to perform with inexpensive radiographic equipment. A radiograph requires little cooperation from the patient. The radiation dose is small. A CT scan is a high-cost procedure that also requires little cooperation from the patient. CT equipment is expensive and delivers a higher radiation dose to the patient. Given the rapid speed of new CT scanners, the time that a patient is lying on the scanner tabletop is nearly equal for a plain radiograph of the abdomen and a CT scan. A plain abdominal radiograph requires no patient preparation. There is about a 1-hour preparation time for a CT scan that uses intravenous (IV) and oral contrast agents.
CT has far greater contrast resolution than a plain abdominal radiograph and is far superior in showing abnormal calcifications or fluid/gas patterns in the viscera or peritoneal space. CT is tremendously superior for assessment of the solid organs. A plain radiograph has better spatial resolution than CT, in particular, the overview scout image of a CT scan (variously termed scanogram or topogram ). A plain abdominal radiograph provides an overall “big picture” for bowel obstruction superior to a CT scan. This advantage is greatly surpassed, however, by the ability of CT to demonstrate individual bowel loops, fluid-filled bowel loops, bowel wall thickness, and intravenous contrast enhancement patterns.
