Activity 1: Properties of Radiopaque Contrast Media Naomi, a former radiologist,

Activity 1: Properties of Radiopaque Contrast Media
Naomi, a former radiologist, has recently joined a new research team. Part of her role is to help develop more effective ways to produce images of body parts whose tissues are particularly low in contrast. As a first step, Naomi begins by establishing the causes of low-contrast properties in biologic (human) tissue. Naomi’s immediate focus is on roentgenography; to start with, she is working only with agents derived from triiodinated benzoic acid.
What parts of the body is Naomi’s team most likely to be concerned about imaging? Why?
What common property in the tissues Naomi is working with makes them particularly low contrast?
Based on what you know from the above, what agents would you predict Naomi might choose to work with first? Why?
One reason Naomi has chosen to work with the specific ROCM identified in question 3 is the fact that iodine molecules are responsible for the silhouette images projected on radiographic film. What makes that true?
At the team’s next meeting, Brad, one of Naomi’s colleagues, reports on the osmotic activity of selected intravascular ROCM. When Naomi asks whether Brad means osmolality or osmolarity, Brad explains to her that the two terms can be used interchangeably in reference to osmotic activity. “The difference between the two measurements is insignificant,” he says.
5. a. What exactly is osmosis, and what conditions must exist for this phenomenon to occur? Describe a highly osmotic agent, and explain how one would act if placed in the bloodstream.
b. Is Brad’s statement true? If so, when? If not, why not?
c. Create a chart Naomi’s team can use when the difference between the two might matter.
Activity 2: Clinical Selection of Radiopaque Contrast Media
Brad, a member of a research team, discovers that he is tired of research. He misses working with patients and the challenges and variations in daily clinical problem-solving. When a position is advertised for an assistant director in a small new community hospital, Brad decides the time is right to leave the research lab environment to return to patient involvement. He wins the position.
One of Brad’s first assignments is orientation training for the new hospital’s radiography staff—many of whom are beginning their first positions in the field. Because he knows hands-on experience sometimes raises excellent questions and will motivate his staff to want to learn, he decides to have an orientation in the second week of work rather than the first.
1. As you solve the questions below, use them to design a table for Brad’s employees that outlines the differences between the three broad categories of intravascular ROCM. Your table should include forms, molecular makeup, and ratios of iodine atoms to osmotically active particles.
Four patients arrive and are prepared by radiography staff members simultaneously. Brad is asked to use a rapid IV injection of intravascular ROCM to enhance Mr. Abbott’s (presumably normal) urinary tract visibility and to create contrast enhancement of Ms. Beckett’s brain. A third patient, Mrs. Chan, requires oral diatrizoate sodium to enhance the radiodensity of the esophagus and stomach, whereas Mr. Deuck will take the same agent for radiodensity of the duodenum. Mr. Edam needs enhanced radiodensity for accurate imaging of the rectum and colon.
Questions 2 through 6 concern these four patients.
If the required ROCM are all administered at the same time, in what order will these patients be ready for the radiographic exam?
Is it possible to determine what route each of the four patients will require for the administration of their ROCM? If so, what are those routes? If not, why not?
Unfortunately, it turns out that Mr. Abbott has some degree of renal impairment. What effect, if any, is this likely to have on the administration of intravascular ROCM?
Mr. Deuck comes back to Brad’s department in 2 days. This time he needs a cholecystography. A technician suggests that Brad administer iodamide meglumine. If you agree, explain why it is the agent of choice. If you disagree, explain why, suggesting an alternative agent.
What is the preferred drug (and route) of choice for Mr. Edam’s enhancement agents (of the rectum and colon)? When might this not be appropriate? What other alternatives are there? Which of these is/are preferred if Mr. Edam’s physician requests Computed Tomography?