Appendix B – Contrast Media

Property	Description	Radiographic Relevance
Formula	BaSO₄ – an insoluble, inert compound	Not absorbed by the body; remains confined to GI tract
Solubility	Insoluble in water and body fluids	Prevents systemic absorption
Density (Weight/Volume)	Usually 30–100 % w/v, depending on exam	Higher density = greater radiopacity
Viscosity	Controlled by suspension additives	Thicker suspensions coat mucosa; thinner flow more readily
Flocculation Control	Additives prevent clumping	Smooth coating ensures diagnostic image detail

Preparation Type	Typical Exams	Example Trade Names	Notes
High-density barium (80–100 % w/v)	Double-contrast UGI, esophagram, BE	E-Z Paque, Varibar Thick	Provides excellent mucosal coating; may be mixed with CO₂ for double-contrast
Medium-density barium (50–70 % w/v)	Routine single-contrast UGI / SBFT	Readi-Cat, Liquid Polibar	Balanced coating and transit characteristics
Low-density barium (30–50 % w/v)	Small-bowel follow-through, pediatric GI	E-Z Paque dilute, Varibar Thin	Allows rapid transit; less coating detail
Varied viscosity preparations	Modified Barium Swallow (MBS/VFSS)	Varibar Thin Liquid, Nectar, Honey, Pudding	Viscosity chosen by speech-language pathologist to simulate food textures

Study Type	Positive Agent	Negative Agent	Purpose
Single-contrast	Barium only	None	Outlines lumen; used when patients cannot tolerate gas distention
Double-contrast	High-density barium	Air or CO₂	Coats mucosa; gas distends lumen for fine detail of folds, ulcers, lesions

Route	Common Exams	Delivery Method	Key Technique Points
Oral	Esophagram, UGI, SBFT, MBS	Cup, straw, syringe, or spoon; sometimes with effervescent granules	Patient positioning and swallowing sequence critical
Rectal	Barium Enema (single or double-contrast)	Gravity bag or mechanical injector; air or CO₂ insufflation for double-contrast	Ensure tip retention balloon is properly inflated; instruct slow, deep breathing
Enteric tube	Enteroclysis, pediatric or postoperative studies	Nasogastric / enteric catheter	Administer under fluoroscopic guidance; use pre-screening for perforation

Additive	Function
Suspending agents (e.g., carboxymethylcellulose)	Maintain even particle distribution
Dispersing agents	Prevent clumping (“flocculation”)
Flavoring / coloring agents	Improve patient tolerance
Methylcellulose components (combo systems only)	Serve as negative-contrast element in dual-phase small-bowel studies

Property	Description	Radiographic Relevance
Base composition	Organic iodine molecules in aqueous solution	High atomic number (Z=53) provides X-ray attenuation
Solubility	Fully water-soluble	Enables IV and enteric use; easily excreted
Viscosity / Osmolality	Controlled by molecular design	Affects patient tolerance and renal safety
Iodine concentration	Typically 240–370 mg I/mL (diagnostic range)	Determines image brightness (radiopacity)
Elimination	Renal (glomerular filtration)	Dose adjustments for renal impairment

Type	Description	Clinical Use	Examples
Ionic (High-Osmolar, HOCM)	Dissociate into ions; hypertonic to plasma	Limited modern use (angiography, some oral agents)	Conray, Hypaque
Nonionic (Low-Osmolar, LOCM)	Do not dissociate; near isotonic	Preferred for IV, enteric, and intrathecal routes	Omnipaque, Isovue, Optiray
Iso-osmolar (IOCM)	Osmolality equal to plasma	Used selectively for high-risk renal patients	Visipaque

Additive	Function
Buffers & stabilizers	Maintain pH and prevent crystallization
Chelating agents	Improve solubility and shelf life
Wetting agents / surfactants	Reduce viscosity, improving injection flow
Flavoring (oral forms)	Improve patient tolerance for enteric use

Negative Contrast Agent	Delivery Form	Typical Exams	Key Notes
Room Air	Manual insufflation	Barium enema (single or double contrast)	Most common negative agent for BE; inexpensive; monitor for cramping
CO₂ Gas	CO₂ insufflator system	Double-contrast BE	Rapid absorption → better comfort & lower perforation risk than room air
Effervescent Crystals	Sodium bicarbonate + citric acid crystals	Esophagram / UGI (double-contrast)	Standard modern method to generate gastric CO₂; instruct patient not to belch
Methylcellulose (combination systems)	Component in dual-contrast kits only (e.g., EnteroVu, Varibar M’cellulose)	Specialty small bowel mucosal studies	Standalone methylcellulose oral solutions no longer produced; used only in combo products to improve mucosal visualization

Column	Purpose
Study / Exam	Identifies the procedure or imaging focus
Contrast	Indicates whether positive or negative contrast (and type) is used
Generic Name	Lists the primary active substance
Common Trade Names	Reflects what technologists will see on product packaging
Route	Clarifies method of administration (oral, rectal, intrathecal, intra-articular, etc.)
Key Notes	Highlights preparation, patient care, and safety details for that procedure

Contraindications / Precautions

• Do not use barium when perforation, fistula, or recent bowel surgery is suspected — use a nonionic low- or iso-osmolar iodinated agent (e.g., iohexol / Omnipaque).
• Avoid diatrizoate-based agents (e.g., Gastrografin, MD-Gastroview) in patients with:
  • Aspiration risk
  • Tracheoesophageal fistula (TEF)
  • Significant dysphagia
• Aspiration of diatrizoate can cause acute pulmonary edema, pneumonitis, or death.
• Effervescent crystals should be used only when the patient can control belching.
• Methylcellulose is no longer produced as a stand-alone negative agent; it is available only in combination products (e.g., Varibar M’cellulose, EnteroVu).
• Confirm pregnancy status prior to fluoroscopic studies involving the abdomen or pelvis.
• Follow pediatric dilution guidelines from the radiologist for age- or weight-adjusted concentrations.

Technique & Safety Notes

• Barium sulfate is the first-choice contrast for GI imaging when perforation is not suspected.
• For suspected perforation, use nonionic, low- or iso-osmolar iodinated contrast (e.g., iohexol / Omnipaque).
• If aspiration risk exists, use thin barium or nonionic iodinated contrast—not Gastrografin.
• Double-contrast (barium + gas) enhances mucosal detail; instruct patients not to belch after ingesting effervescent crystals.
• CO₂ is preferred over room air for double-contrast BE due to better tolerance and faster absorption.
• Always document contrast name, concentration, volume, route, and lot number.
• Observe closely during swallowing; stop immediately for any distress, cough, or choking.
• Encourage hydration after the procedure to prevent constipation or barium impaction.

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Genitourinary (GU) Contrast Media Reference

Genitourinary contrast procedures are performed to evaluate the kidneys, ureters, bladder, urethra, and reproductive organs.
All studies use water-soluble iodinated contrast, most commonly nonionic low- or iso-osmolar formulations, to provide clear visualization while minimizing patient discomfort and mucosal irritation.

Study / Exam	Contrast	Generic	Common Trade Names	Route	Key Notes
Intravenous Urogram (IVU / IVP)	Nonionic iodinated	Iohexol / Iopamidol	Omnipaque 300–350 / Isovue-300–370	IV injection	Visualizes kidneys, ureters, and bladder. Hydrate before and after. Obtain timed films (nephrogram through cystogram phases). Screen renal function per site policy.
Retrograde Pyelogram	Nonionic iodinated (low-osmolality)	Iohexol / Iopamidol	Omnipaque / Isovue	Catheter via cystoscope into ureter	Performed in cysto suite under sterile technique. No renal function labs required. Inject gently to prevent pyelovenous reflux.
Cystogram (Retrograde)	Nonionic iodinated	Iohexol / Iopamidol	Omnipaque / Isovue	Foley catheter instillation into bladder	Demonstrates bladder contour, reflux, and rupture. Avoid ionic agents (cause burning and spasm). Fill until patient sense of fullness (≈300–400 mL).
Voiding Cystourethrogram (VCUG)	Nonionic iodinated	Iohexol / Iopamidol	Omnipaque / Isovue	Foley catheter; patient voids under fluoro	Evaluates vesicoureteral reflux. Provide privacy, especially for pediatric patients. Stop if spasm or pain occurs.
Urethrogram (Retrograde Male)	Nonionic iodinated	Iohexol / Iopamidol	Omnipaque / Isovue	Catheter cone tip at urethral meatus	Evaluate urethral trauma or stricture. Warm contrast to reduce discomfort. Use low-pressure injection.
Hysterosalpingogram (HSG)	Nonionic iodinated	Iohexol / Iomeprol	Omnipaque / Iomeron	Intrauterine catheter	Performed during early follicular phase. Demonstrates uterine cavity and tubal patency. Expect mild cramping; use sterile technique.
Nephrostogram	Nonionic iodinated	Iohexol / Iopamidol	Omnipaque / Isovue	Through existing nephrostomy tube	Confirms tube placement and drainage under fluoro. Use minimal contrast volume.
Loopogram	Nonionic iodinated	Iohexol / Iopamidol	Omnipaque / Isovue	Catheter into ileal conduit or urinary diversion	Evaluates stoma integrity and reflux after urinary diversion surgery. Use gentle manual injection.
Fallopian Tube Recanalization (Special procedure)	Nonionic iodinated	Iohexol	Omnipaque	Microcatheter under fluoroscopic guidance	Performed by interventional radiologist. Diagnostic and potentially therapeutic.

Contraindications / Precautions

• Active urinary tract infection — defer elective retrograde or cystographic studies until treated.
• Recent bladder or urethral surgery — confirm clearance from urologist.
• Ionic (high-osmolality) agents may cause severe discomfort or mucosal irritation — avoid.
• Always check for pregnancy prior to pelvic procedures (VCUG, HSG).
• Use aseptic technique for all catheter-based studies.

Technique & Safety Notes

• Verify patient identity, procedure, and contrast type before administration.
• Warm contrast to body temperature to reduce spasm and discomfort.
• Maintain sterile field during catheterization and injection.
• Document contrast name, concentration, volume, route, and lot number.
• Observe for vasovagal reaction during bladder distention; lower bag and elevate legs if needed.
• Provide post-procedure instructions: mild dysuria or urgency is normal; encourage fluids.

Key Concepts for Practice

• All GU exams use water-soluble iodinated contrast; nonionic agents are preferred for comfort and safety.
• Ionic agents are contraindicated for retrograde or intraluminal use due to mucosal irritation.
• IVU assesses renal function dynamically; retrograde studies assess structure only.
• Cystogram / VCUG evaluate reflux, rupture, or outlet obstruction.
• HSG performed in early cycle to avoid pregnancy; confirms tubal patency.
• Warmed contrast = fewer spasms; sterile technique = fewer infections.
• Always document contrast details and patient response.

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Special Procedures Contrast Reference

Special procedures such as myelography, arthrography, and fistulography use targeted contrast administration to evaluate specific anatomic structures and functional relationships.
All procedures require meticulous sterile technique, correct agent selection, and close patient monitoring before, during, and after contrast injection.

Contraindications / Precautions

• Ionic contrast agents are strictly contraindicated for intrathecal use — only nonionic, intrathecal-approved agents (e.g., Omnipaque 180, 240, 300) may be used for myelography.
• Confirm no known contrast allergy or prior severe reaction before injection.
• Anticoagulant therapy may increase bleeding risk during needle procedures; follow facility policy regarding INR or platelet count verification.
• Active infection at puncture or joint site contraindicates injection until treated.
• For myelography, ensure no recent lumbar puncture or procedure within the previous 24 hours that could affect CSF flow.
• Pregnancy is a relative contraindication for fluoroscopic myelography; verify status per facility protocol.

Technique & Safety Notes

• Maintain strict sterile technique for all invasive procedures (myelogram, arthrogram, fistulogram).
• Verify the contrast label before opening — it must state “For Intrathecal Use” when performing a myelogram.
• For myelography:
  • Elevate the head of the table ~30° post-procedure to reduce risk of post-dural puncture headache.
  • Monitor neurologic status during and after injection.
  • Contrast flows within the subarachnoid space; use table tilt to control distribution (Trendelenburg for cervical fill, reverse Trendelenburg for lumbar).
• For arthrography:
  • Common joints: shoulder, hip, knee, wrist, ankle.
  • Use double-contrast (iodinated + air/CO₂) when mucosal or cartilage detail is desired.
  • Perform time-out, local anesthetic, and informed consent before the procedure.
• For fistulograms/sinograms:
  • Use low-osmolar, nonionic iodinated contrast.
  • Inject gently to define sinus tracts; avoid overdistention.
• Document contrast name, concentration, volume, lot number, expiration date, site, and laterality for every procedure.

Key Concepts for Practice

• Intrathecal contrast must be nonionic and explicitly labeled for intrathecal use.
• Ionic contrast → never intrathecal.
• Myelography visualizes the spinal cord and nerve roots within the subarachnoid space; used when MRI is contraindicated or nondiagnostic.
• Arthrography evaluates joint capsule, synovium, and cartilage surfaces; double-contrast improves detail.
• Fistulograms identify the extent and communication of abnormal tracts using low-osmolar iodinated contrast.
• Sterility and verification are essential — infection prevention and contrast identification are critical safety steps.
• Contrast allergy protocols apply to all iodinated injections.
• Document thoroughly and monitor patients post-procedure for headache, pain, or allergic symptoms.

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Patient Screening & Documentation 

Patient screening and documentation are essential components of safe contrast administration.
Radiographers are responsible for verifying patient identity, assessing for risk factors or contraindications, confirming correct contrast selection, and recording all procedural details and patient responses.

Pre-Procedure Verification

Before beginning any contrast study:

• Verify patient identity using two identifiers (e.g., name and date of birth).
• Confirm the clinical indication and ensure the correct exam has been ordered.
• Confirm the contrast agent, route, and dose with the radiologist or protocol.
• Verify consent according to facility policy — verbal for GI exams, written for intrathecal or joint injections.
• Review available imaging and medical history for recent surgery, leaks, or contraindications.

Risk Assessment

Before administering any contrast agent, evaluate the patient for potential risk factors that may increase the likelihood of an adverse reaction or complication.
This assessment should include allergy history, renal and metabolic status, respiratory or swallowing safety, and other medical conditions that could influence contrast tolerance or procedural safety.

Allergy & Reaction History

• Ask about any previous contrast reactions — document type, severity, and timing.
• Clarify allergies to iodine, shellfish, or betadine (not true contraindications but still important for documentation).
• Note allergies to latex, medications, or foods that may impact supplies or emergency response.

Renal & Metabolic Risk

• Identify renal disease, dialysis, or transplant history.
• Ask about diabetes or metformin use and follow facility policy for timing of medication hold and restart.
• Creatinine/eGFR is required only when risk factors are present, per ACR guidance.

Respiratory & Swallow Safety (GI Exams)

• Assess for dysphagia or aspiration risk before oral contrast.
• If tracheoesophageal fistula (TEF) or high aspiration risk is suspected, avoid diatrizoate (Gastrografin) and use barium or nonionic iodinated contrast instead.

Other Conditions

• Identify asthma, cardiac disease, or beta-blocker use (may affect emergency medication response).
• Confirm anticoagulation status for needle procedures (arthrogram, myelogram).
• Assess for pregnancy and follow site screening policy.
• Confirm no infection at puncture site for invasive procedures.

Administration & Monitoring

During contrast preparation and administration, radiographers must follow strict safety and verification procedures to ensure correct agent selection, accurate dosing, and patient well-being throughout the exam.

• Verify contrast name, concentration, and expiration date.
• Confirm the right patient, right exam, right contrast, right route, and right dose before administration.
• Ensure emergency drugs, oxygen, and suction are immediately available—particularly for intravenous or intrathecal studies.
• Observe the patient continuously for discomfort, cough, rash, or changes in breathing or responsiveness.
• If any distress occurs, stop the procedure immediately and notify the radiologist.
• For myelograms, maintain the head of bed elevation (~30°) post-procedure to minimize post-dural puncture headache.
• Encourage hydration if medically appropriate after iodinated contrast to aid renal clearance.

Documentation Standards

Accurate charting and communication are essential for both clinical and legal safety.

Document the following for every contrast procedure:

Item	Example / Notes
Contrast name	“Omnipaque 300”
Dose / Volume & Route	75 mL IV; 100 mL oral; 10 mL intra-articular
Concentration	300 mg I/mL
Lot number & Expiration	Off vial label
Manufacturer / NDC (if required)	From vial
Site & laterality (if applicable)	L shoulder joint
Patient response	“Tolerated well”
Complications or interventions	“O₂ given for mild dyspnea; resolved”
Provider notification & time	“Radiologist notified at 14:35”
Post-procedure instructions	“Encourage fluids; HOB 30° × 4 hr”

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Contrast Reactions & Emergency Management

Although serious reactions to contrast media are uncommon, all radiographic staff must be prepared to recognize and respond immediately.
Early identification of symptoms, prompt activation of the emergency protocol, and accurate documentation are critical for patient safety and quality care.

Quick Response Reference

Symptom	Concern
Coughing, gagging, or choking	Aspiration risk
Hives, itching	Mild allergic reaction
Wheezing, throat tightness, or dyspnea	Anaphylactoid reaction
Change in voice or drooling	Airway obstruction threat
Confusion or agitation	Hypoxia or vascular event
Hypotension or syncope	Severe reaction or shock

If any of these symptoms occur, stop the exam immediately, call for assistance, and notify the radiologist.

Types of Contrast Reactions

Contrast reactions are idiosyncratic (not true allergies) but are managed as allergic responses.

Contrast Extravasation

Contrast Reaction Algorithm

1. Stop contrast injection or swallow immediately
2. Call for assistance or activate Code if severe
3. Maintain airway — provide O₂, suction, and ventilatory support as needed
4. Monitor vital signs continuously
5. Administer emergency medications per protocol
6. Document all actions, medication doses, and times
7. Complete incident and adverse-event reports per policy

Source: American College of Radiology (2024). ACR Manual on Contrast Media (pp. 49–62). Doses align with ACR and ARRT clinical competencies; confirm local standing orders before use.

Key Concepts for Practice

• Most common reaction: mild nausea, warmth, or urticaria
• Most dangerous reaction: laryngeal edema → airway obstruction
• First-line medication: epinephrine IM (1:1000)
• Monitor for at least 30 minutes post-contrast for delayed effects
• Extravasation: stop injection, elevate limb, apply cold compress, document
• Vasovagal: bradycardia + hypotension → Trendelenburg + atropine
• Never inject ionic contrast intrathecally
• Always verify contrast label before use
• Document all reactions, interventions, and outcomes immediately

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Exam Sequencing and Rationale

When multiple contrast studies are ordered for the same patient, the sequence must minimize residual contrast interference and protect patient safety.
Proper sequencing ensures diagnostic accuracy, prevents contrast contamination between studies, and reduces patient risk from repeated exposure.

Standard Exam Sequencing

Order	Exam Type	Reason / Rationale
1	Non-contrast procedures (plain films, fluoroscopy without contrast)	Establish baseline anatomy and pathology before contrast introduction.
2	Urinary tract studies (IVU, cystogram, VCUG)	Iodinated contrast clears quickly via kidneys; later exams may interfere with renal visualization.
3	Biliary system studies (cholangiography, ERCP)	Prevents delay from residual barium in bowel loops that could obscure ducts.
4	Gastrointestinal series with barium (esophagram, UGI, SBFT, BE)	Barium remains in the GI tract for hours or days; performing these first could obscure other anatomy.
5	CT or MRI with IV contrast (if same-day scheduling)	Cross-sectional exams are least affected by previous fluoroscopic contrast, but residual GI barium can degrade image quality.
6	Nuclear medicine studies	Should follow radiographic exams by at least 24 hours if barium or iodinated oral contrast was used, to avoid attenuation artifacts.

Special Sequencing Considerations

• Barium follow-through after UGI:
  Performed immediately following the upper GI series using the same oral contrast; do not repeat barium ingestion unless directed.
• Post-operative or leak studies:
  Always use water-soluble iodinated contrast first to confirm integrity before introducing barium.
• When both iodinated and barium agents are ordered:
  Perform iodinated study first, then barium—iodine clears faster and will not obscure subsequent studies, whereas barium can remain for days.
• Pediatric sequencing:
  Minimize total fluoroscopy time; group related procedures (e.g., VCUG followed by UGI if both required) under one exposure period when feasible.
• Interdepartmental coordination:
  Communicate with CT, MRI, and Nuclear Medicine staff to prevent residual contrast interference and optimize timing between modalities.

Key Concepts for Practice

• Always confirm exam order with the radiologist when multiple contrast procedures are scheduled.
• Iodinated contrast clears rapidly; barium persists, so barium exams should be last.
• Water-soluble contrast is required whenever perforation or leak is suspected.
• Residual barium can obscure other exams for several days—document use and advise follow-up staff.
• Sequence exams to protect renal function, reduce radiation exposure, and avoid redundant injections.
• Effective communication among radiology, CT, and nuclear medicine teams ensures both safety and image quality.

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Key References

American College of Radiology. (2024). ACR manual on contrast media (Version 11). American College of Radiology. https://www.acr.org/Clinical-Resources/Contrast-Manual

Baert, A. L., & Knauth, M. (2009). Contrast media in practice: Safety, indications, and protocols (2nd ed.). Springer.

Ehrlich, R. A., & Coakes, D. M. (2024). Patient care in radiography: With an introduction to medical imaging (11th ed.). Elsevier.

European Society of Urogenital Radiology. (2018). ESUR guidelines on contrast agents: Version 10.0. https://www.esur.org/guidelines

Mosby. (2023). Mosby’s comprehensive review of radiography: The complete study guide and career planner (9th ed.). Elsevier.

Radiologic Society of North America. (2024). Contrast agent information for patients and professionals. https://www.radiologyinfo.org/en/info/safety-contrast 

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