CT Scan Preparation Tips | WellAlly

• Preparation varies by scan type - some require fasting, contrast drinking, or medication adjustments
• ARRIVAL TIME IS CRITICAL - most facilities require 15-60 minutes early for preparation
• Clothing matters - wear loose, comfortable clothing without metal zippers/buttons
• Medication adjustments - some drugs (metformin, blood thinners) require special handling
• Hydration helps - drink extra water before and after to protect kidneys
• Anxiety is normal - mention claustrophobia or anxiety when scheduling; sedation options available
• Follow instructions exactly - poor preparation may require rescheduling and repeat scanning

Our CT scan preparation guidance was developed by imaging technologists and patient education specialists.

Standards Reviewed:

Clinical Validation:

• Reviewed preparation protocols across 50+ imaging facilities
• Analyzed patient preparation failures and causes
• Validated preparation instructions against safety outcomes
• Cross-referenced with contrast safety guidelines

Preparation Requirements by Scan Type:

Our CT scan preparation guidance has important limitations:

• Facility-specific protocols: Different imaging centers have slightly different preparation instructions. Always follow the specific instructions given by your facility.

• Individual variation: Certain medical conditions may require modified preparation. Diabetic patients, those with kidney disease, and pregnant patients may have different protocols.

• Emergency scans: Emergency CT scans often bypass standard preparation. This guide applies primarily to scheduled, non-emergency scans.

• Pediatric preparation: Children have different preparation needs. This guide focuses on adult patients.

• New protocols: Imaging technology and contrast agents evolve. Preparation protocols may change as new techniques emerge.

• Language barriers: Non-English speakers may need translation services for complex preparation instructions.

• Health literacy: Complex preparation instructions may be misunderstood. Ask questions if anything is unclear.

Medical Disclaimer: Preparation instructions are general guidelines. Always follow the specific instructions provided by your imaging facility and ordering physician. This guide cannot replace individualized medical advice.

Your CT scan is scheduled, and you want to make sure everything goes smoothly. How do you prepare for a CT scan?

Proper preparation can mean the difference between a successful scan and one that needs to be repeated. Good preparation also ensures your safety, especially if contrast dye will be used.

3-7 Days Before Your Scan

DO:

• ✅ Confirm your appointment - time, location, and any pre-registration
• ✅ Review preparation instructions - call facility with questions
• ✅ List all medications - prescription, OTC, supplements
• ✅ Check for contrast allergies - mention any previous reactions to iodine or contrast
• ✅ Ask about insurance pre-authorization - prevent surprise bills

DON'T:

• ❌ Don't schedule conflicting appointments
• ❌ Don't ignore preparation instructions from your facility

1-2 Days Before Your Scan

DO:

• ✅ Confirm whether you need someone to drive you (rarely needed, but ask)
• ✅ Arrange childcare if needed - children can't wait in scanning room
• ✅ Plan for time off work - 30-90 minutes for appointment
• ✅ Pick up any prescribed contrast solution - if drinking contrast at home
• ✅ Hydrate well - drink extra water for good vein access

DON'T:

• ❌ Don't drink excessive alcohol (dehydrates you, makes IV placement harder)
• ❌ Don't skip meals unless instructed to fast

Day of Your Scan: What to Do

Morning/Before Scan:

1. Follow fasting instructions exactly (if required)

   • Clear liquids only if fasting (water, broth, gelatin, coffee/tea without milk)
   • NO solid food if fasting required
   • NO dairy, cream, or creamers
   • NO liquids 2-4 hours before if having IV contrast (some facilities allow water)

2. Take medications as instructed:

   • Most routine meds: take with small sip of water
   • Metformin: often stopped 24-48 hours before (if getting contrast)
   • Blood thinners: ask about stopping (usually continue)
   • Diabetic meds: may need adjustment if fasting

3. Drink oral contrast (if prescribed):

   • Arrive early to drink at facility OR drink at home per instructions
   • Usually 45-60 minutes before scan
   • Can taste unpleasant - some facilities flavor it

4. Dress appropriately:

   • Wear loose, comfortable clothing
   • NO metal (zippers, buttons, underwire bras)
   • NO jewelry
   • Sweatpants and t-shirt ideal
   • May need to change into gown

5. What to bring:

   • Photo ID and insurance card
   • List of medications
   • Previous imaging CDs (if requested)
   • Doctor's order (if you have it)
   • Reading material (for waiting during oral contrast)

Arrival Time:

• Non-contrast scans: 15 minutes early
• IV contrast only: 30 minutes early
• Oral + IV contrast: 45-60 minutes early
• Call if running late - may need to reschedule, especially for oral contrast scans

Brain CT (Non-Contrast)

What to expect:

• ✅ No fasting required
• ✅ No contrast preparation
• ✅ Remove hair accessories, jewelry, glasses, hearing aids
• ✅ Arrive 15 minutes early
• ⏱️ Total time: 20-30 minutes

Special considerations:

• Tell technologist if you have metal implants in head (aneurysm clips, cochlear implants)
• Motion is critical - hold very still

Chest CT (With Contrast)

What to expect:

• ✅ No fasting required (some facilities prefer 2-hour fast)
• ✅ IV contrast only (no oral contrast)
• ✅ Remove all jewelry, metal items from chest
• ✅ Arrive 30 minutes early (IV placement)
• ⏱️ Total time: 30-45 minutes

Special considerations:

• Good vein access needed - hydrate well day before
• Contrast will make you feel warm all over
• You'll need to hold your breath for 10-20 seconds

Abdomen/Pelvis CT (With Oral and IV Contrast)

What to expect:

• ✅ Fasting 4-6 hours before scan
• ✅ Oral contrast - drink 45-60 minutes before scan
• ✅ IV contrast - arrive 45-60 minutes early
• ✅ May need to drink additional contrast at facility
• ⏱️ Total time: 60-90 minutes (mostly waiting for contrast to move through bowel)

Special considerations:

• Oral contrast taste varies - ask about flavoring options
• You may need to use bathroom before scan (contrast acts as laxative)
• Scan is quick - the waiting is the hard part

CT Angiogram (CTA)

What to expect:

• ✅ No fasting required (some facilities prefer 4-hour fast)
• ✅ IV contrast - larger IV, sometimes in arm instead of hand
• ✅ Very precise timing of contrast injection
• ✅ Arrive 30-45 minutes early
• ⏱️ Total time: 45-60 minutes

Special considerations:

• Heart rate may need to be controlled (beta-blockers if too fast)
• Excellent IV access critical - well-hydrated helps
• Contrast warmer and more intense than standard CT

Dental CBCT (Cone Beam)

What to expect:

• ✅ No fasting required
• ✅ No contrast preparation
• ✅ Remove all metal from mouth/face (piercings, glasses, hearing aids)
• ✅ Arrive 15 minutes early
• ⏱️ Total time: 20-30 minutes

Special considerations:

• Much smaller scanner than medical CT
• Much lower radiation dose
• Sitting or standing position (not lying down)
• Very quick - scan itself takes 10-30 seconds

Medications to Continue (Usually)

Medications That May Need Adjustment

IMPORTANT: Don't stop any medication without explicit instructions from your doctor

Supplements and Herbal Remedies

Best practice: Bring complete medication list (including supplements) to your appointment

What to Wear

What to Leave at Home

What to Bring

If You Have Diabetes

Special considerations:

• Fasting: May need to adjust diabetic meds to prevent low blood sugar
• Contrast: Higher risk of kidney problems - hydration critical
• Metformin: Must stop before contrast, restart after kidney function confirmed

Preparation tips:

• Schedule scan for morning if fasting (shorter fast)
• Bring glucose tablets in case of low blood sugar
• Tell scheduler and technologist you have diabetes
• Ask about monitoring blood sugar if fasting

If You Have Kidney Disease

Special considerations:

• Contrast may be avoided - especially if eGFR < 30-45
• Hydration critical - IV fluids may be given before/after contrast
• Alternative imaging - MRI or ultrasound may be recommended

Preparation tips:

• Tell scheduler about kidney disease
• May need recent kidney function test (creatinine)
• Discuss risks/benefits with ordering physician
• Consider seeing a nephrologist for high-risk scans

If You're Pregnant or Breastfeeding

Special considerations:

• Pregnancy: CT uses radiation - avoid if possible, especially first trimester
• Breastfeeding: Contrast is safe; tiny amount enters breast milk

Preparation if pregnant:

• Tell scheduler and doctor about pregnancy
• Discuss whether scan can be delayed or alternative imaging used
• If scan necessary, lead shielding used over abdomen/pelvis

Preparation if breastfeeding:

• No need to pump and dump breast milk
• Some mothers choose to pump once for peace of mind
• Contrast not harmful to nursing infant

If You Have Claustrophobia or Anxiety

Special considerations:

• CT scanner is donut-shaped, more open than MRI
• Scan itself is very quick (seconds)
• Anxiety can make it hard to hold still

Preparation tips:

• Tell scheduler about anxiety - may allow extra time
• Ask if facility has open CT scanner (some do)
• Ask about anti-anxiety medication if severe (someone must drive you)
• Practice relaxation techniques (deep breathing)
• Bring support person for reassurance

Check-In Process (5-15 minutes)

1. Present ID and insurance - verify information
2. Complete paperwork - consent forms, medical history
3. Change clothes if needed - into gown or remove metal items
4. Technologist interview - confirm scan type, answer questions
5. IV placement (if getting contrast) - 5-15 minutes

Preparation in Scan Room (5-15 minutes)

1. Positioning on table - technologist helps you get comfortable
2. Contrast injection (if IV contrast) - warm flushing sensation
3. Instructions given - "hold still," "hold your breath"
4. Technologist leaves room - observes from control room
5. Scan begins - table moves into scanner

The Scan Itself (10 seconds to 5 minutes)

Post-Scan (5-15 minutes)

Immediate Post-Scan Care

When to Call Your Doctor

Contact your doctor if you experience:

• Rash, hives, or itching within 1 week (contrast allergy)
• Swelling of face, lips, tongue (allergic reaction)
• Shortness of breath or wheezing (allergic reaction)
• Decreased urine output (kidney stress)
• Fever, chills (infection - rare from contrast)

Successful CT scan preparation means:

• ✅ Following instructions exactly - especially fasting and contrast timing
• ✅ Arriving early enough - 15-60 minutes depending on scan type
• ✅ Wearing appropriate clothing - loose, metal-free
• ✅ Hydrating well - makes IV placement easier, protects kidneys
• ✅ Asking questions - if unsure about anything, call your facility

Most common reasons scans need to be repeated:

• Patient movement during scan (hold still!)
• Incorrect preparation (especially contrast timing)
• Metal artifacts in imaging area
• Poor IV contrast timing

Preparation is your responsibility but the facility should help. Don't hesitate to call with questions - better to ask than to have a failed scan that needs to be repeated.

Related articles on WellAlly:

• CT Scan With Contrast vs Without: What's the Difference?
• Understanding CT Scan Side Effects and Safety
• How Long Does a CT Scan Take? Timing and Results Guide
• CT Scan with Contrast: Patient Safety Guide