ARRT RRA flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Normal adult respiratory rate

12 to 20 breaths per minute at rest. Rates outside this range, especially with distress or cyanosis, require assessment and notification of the radiologist before proceeding.

Normal adult pulse range

60 to 100 beats per minute. Tachycardia with hypotension may indicate shock, while bradycardia may reflect medication effect or conduction abnormality.

Signs of anaphylaxis

Laryngeal edema, bronchospasm, hypotension, and urticaria occurring after contrast administration. Management includes epinephrine, oxygen, and IV fluids.

Extravasation first response

Stop the injection, remove the cannula, elevate the limb, apply a cold compress, and document volume and site. Monitor for swelling, pain, and compartment syndrome.

Gadolinium contraindication threshold

eGFR below 30 mL/min/1.73 m2 or dialysis dependence increases nephrogenic systemic fibrosis risk. Confirm renal function before administering gadolinium-based contrast.

Metformin and iodinated contrast

Hold metformin for 48 hours after contrast in patients with reduced renal function or acute kidney injury. Resume only after renal function is confirmed stable.

Airborne precautions

Used for tuberculosis, varicella, and measles. Requires a negative-pressure room and an N95 respirator for all entering personnel.

Universal precautions principle

Treat all blood and body fluids as infectious. Wear gloves for contact with nonintact skin or mucous membranes and perform hand hygiene before and after every patient.

Vital sign monitoring during contrast

Assess pulse, blood pressure, respiration, and skin status before and after contrast. Changes such as hypotension or dyspnea prompt immediate cessation and radiologist notification.

Magnification factor formula

Magnification factor equals SID divided by SOD, where SOD is source-to-object distance. Larger SID and smaller object-to-image distance reduce magnification.

Grid ratio selection rule

Use approximately 5:1 below 70 kVp, 8:1 for 70 to 90 kVp, and 10:1 to 12:1 above 90 kVp. Higher ratios require more precise centering and higher mAs.

The 15 percent rule

A 15 percent increase in kVp doubles receptor exposure, and a 15 percent decrease halves it. Compensate by halving or doubling mAs to maintain exposure.

Automatic exposure control setup

Select the chamber aligned with the anatomy of interest, center the part over that chamber, and set a backup time to prevent overexposure if the chamber fails.

Fluoroscopy dose reduction

Use pulsed fluoroscopy, last-image hold, minimal table-to-intensifier distance, and collimation. These measures apply the ALARA principle during fluoroscopic procedures.

Power injector cannula gauge

A 20 to 22 gauge cannula in a large antecubital vein is typical for power injection. Confirm blood return and patency with saline before contrast.

Low-osmolar contrast advantage

Nonionic low-osmolar agents cause less pain, nausea, and renal stress than high-osmolar ionic agents. They are preferred for intravenous administration.

Iodinated contrast reaction categories

Mild includes flushing and hives; moderate includes vomiting and bronchospasm; severe includes laryngeal edema, hypotension, and anaphylaxis requiring epinephrine.

mA and exposure time

Milliamperage multiplied by exposure time in seconds equals mAs. mAs controls receptor exposure and is the primary determinant of image noise.

kVp and subject contrast

Kilovoltage peak controls beam penetrability and subject contrast. Higher kVp lowers contrast and increases scatter; lower kVp raises contrast and patient dose.

Patient positioning for chest radiography

Upright PA at 72 inches SID with shoulders rolled forward and chin elevated. Full inspiration to 10 posterior ribs improves detection of subtle disease.

Receptor exposure indicator

A numeric value reflecting radiation reaching the digital receptor. Values outside the acceptable range indicate under- or overexposure and require technique correction.

Quantum mottle cause

Insufficient photons reaching the receptor produce grainy noise. Increasing mAs increases photon count and reduces quantum mottle in the image.

Spatial resolution definition

The ability to image small objects as separate structures, measured in line pairs per millimeter. Smaller focal spot and pixel size improve it.

Anode heel effect

Beam intensity is higher on the cathode side of the field. Position thicker anatomy toward the cathode to equalize receptor exposure across the image.

Histogram left shift

A histogram shifted toward lower values indicates underexposure and increased noise. Shifted right indicates overexposure and unnecessary patient dose.

Contrast resolution definition

The ability to distinguish tissues with similar attenuation. It improves with higher detector bit depth and lower image noise.

Motion artifact appearance

Blur or ghosting on the image caused by patient or equipment movement. Short exposure time and immobilization reduce its occurrence.

Magnification in image evaluation

Enlargement of the recorded image relative to the object. It increases with shorter SID and greater object-to-image-receptor distance.

Shape distortion causes

Elongation occurs when the object is angled relative to the beam; foreshortening occurs when the receptor is angled relative to the object. Alignment prevents both.

Grid cutoff appearance

Progressive loss of density toward the periphery of the image, caused by improper centering, wrong SID, or angulation with a focused grid.

Focal spot size effect

A smaller focal spot improves spatial resolution and recorded detail but limits tube current. Larger spots permit higher mA and shorter exposure times.

Beam collimation purpose

Restricting the field reduces patient dose and scatter and improves contrast. Collimation also defines the area of interest for evaluation.