Why Preparation Matters More for This Scan Than Most

A CT coronary angiography is not a simple static picture. Three key physiological factors must align on the day, or the scan images will not be diagnostic:

1. Heart Rate Control

The scanner times its image capture precisely to your heartbeat. A fast or irregular rhythm blurs the coronary arteries — which is why caffeine is strictly restricted and beta blockers may be given.

2. Kidney Function (eGFR)

Iodinated contrast dye is filtered through your kidneys. A recent kidney function (eGFR) report ensures your body can clear the dye safely before proceeding.

Doctor’s Order Overrides

Your referring doctor’s specific instructions override anything on this page. Bring your prescription, disclose all current medications, and never stop any prescribed medication on your own.

The Preparation Checklist: Step-by-Step

Read this checklist when you book your appointment, and review it again the evening before your scan:

48 Hours Before

Initial Verification & Medical Disclosure

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    Confirm Kidney Function (eGFR) Report: Ensure you have an eGFR report from the past 4–6 weeks. Karauli Diagnostics offers home sample collection across Varanasi if you need one arranged.
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    Disclose Erectile Dysfunction Medication: Inform the team if taking sildenafil, tadalafil, or vardenafil. A nitrate spray given during the scan to widen coronary arteries can cause a dangerous drop in blood pressure when combined with these drugs. Disclose privately when booking.
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    Flag Allergies & Conditions: Inform staff of any prior contrast dye reactions, asthma, thyroid disease, or severe allergies.
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    Pregnancy Status: Declare immediately if you are or might be pregnant, as CT involves ionising radiation.
24 Hours Before

Dietary & Medication Controls

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    Stop All Caffeine: Avoid tea, coffee, cola, energy drinks, and green tea. Caffeine directly increases heart rate and is the #1 cause of poor scan images or delays.
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    Avoid Alcohol: Do not consume alcoholic beverages for 24 hours prior to the test.
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    Check Diabetes Medication (Metformin): Ask your referring doctor if metformin needs to be paused for 48 hours post-contrast based on your eGFR level. Do not stop without doctor direction.
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    Organise Documents: Put your prescription, past reports, and ID in one folder.
Morning of the Scan

Final Arrival Guidelines

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    Fasting Rules: Follow fasting instructions — typically 4 hours of fasting prior to your slot.
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    Hydration: Drink plain water as advised. Staying well-hydrated assists kidney dye clearance.
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    Take Prescribed Medicines: Take regular medications (including prescribed beta-blockers) with a small sip of water unless advised otherwise.
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    Clothing & Accessories: Wear loose, comfortable clothes. Leave metallic chains, jewellery, and accessories at home.
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    Arrive On Time: Slots are timed for heart-rate preparation. Arriving late compresses preparation time and reduces image quality.

What to Bring to Your Appointment

Gather these documents into a single folder so nothing is missing at registration:

Document Required Why It Matters
Doctor’s Prescription / Referral CTCA is performed strictly on medical referral. The scan cannot proceed without it.
Kidney Function (eGFR) Report The #1 reason for rescheduled scans. Verifies kidneys can clear contrast dye safely.
Previous ECG, TMT & 2D Echo Reports Provides crucial clinical context for the radiologist reading your cardiac scan.
Current Medicines List Includes exact names and dosages (photographing medication strips is acceptable).
Prior Angiography, Stent or Bypass Records Essential for comparing past structural interventions against current coronary anatomy.
ID & Insurance Details Required for registration verification and cashless / reimbursement claims.

Medicines & Conditions to Disclose When Booking

Inform our team about any of the following during booking — not on the scan table:

Diabetes & Metformin

May require temporary suspension post-scan depending on kidney eGFR numbers.

Kidney Disease / Low eGFR

Determines contrast dye eligibility and pre-scan hydration requirements.

Contrast Dye Allergies

Previous reactions (itching, hives, swelling) require pre-medication protocol.

Asthma & Severe Allergies

Allows clinical team to prepare anti-allergy precautions prior to dye injection.

Thyroid Disease

Iodinated contrast can transiently affect thyroid hormone levels.

PDE5 Inhibitors (ED Meds)

Sildenafil / Tadalafil must be avoided 48h prior due to nitrate spray hypotension risk.

BP & Beta-Blocker Meds

Helps team calibrate pre-scan heart rate control protocols.

Pregnancy Status

Ionising radiation risk requires immediate clinical review.

Minute by Minute: What Actually Happens

Plan for 1 to 2 hours total at the centre. The scan capture itself takes only seconds — almost all time is spent on precise preparation:

10–15 Mins

1. Registration & Paperwork

Prescription is verified, kidney function reports reviewed, and medical consent explained.

10 Mins

2. Clinical Assessment

Heart rate and blood pressure are measured. Staff confirm fasting, caffeine stoppage, and allergy history.

30–60 Mins

3. Heart-Rate Control (If Required)

If heart rate is above target (>65 bpm), a oral or IV beta-blocker is given. You rest comfortably while it takes effect.

2 Mins

4. IV Cannula Placement

A standard small IV cannula is inserted into an arm vein for contrast administration.

5 Mins

5. Positioning & ECG Setup

You lie on the scanner couch. ECG electrodes are attached to sync scan timing to your pulse. The technologist practises breath-holding with you.

1 Min

6. Sublingual Nitrate Spray (If Used)

A quick spray under the tongue widens coronary arteries for ultra-clear imaging (may cause brief mild flushing).

Seconds

7. The 384-Slice CT Scan

Contrast is injected automatically, you hold your breath for 10–15 seconds, and high-resolution 3D images are captured instantly.

15–20 Mins

8. Post-Scan Observation

You rest while radiologists verify diagnostic image quality and confirm no allergic response. IV cannula is removed, and you can depart.

What You Will Feel — And Why It’s Completely Normal

Knowing what sensations to expect prevents unnecessary alarm during the scan:

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Spreading Warmth

A warm sensation spreading through your chest, abdomen, and groin as contrast enters. Some feel as though they’ve wet themselves — this is an illusion and passes in seconds.

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Metallic Taste

A temporary metallic or salty taste in your mouth during contrast injection. Completely harmless and fades quickly.

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Brief Flushing / Headache

If nitrate spray was administered under the tongue, a mild transient headache or face warmth may occur.

When to Alert Staff Immediately

Tell the technologist right away if you experience itching, skin rash, facial swelling, difficulty breathing, or severe dizziness. Contrast reactions are rare, but our medical team is fully equipped to treat them promptly.

After the Scan & Recovery Care

Post-Scan Instructions

• Drink plenty of water (1.5–2 litres) for the rest of the day to flush contrast dye from your kidneys.
• Resume normal driving, work, and eating immediately — there is no sedation or recovery downtime.
• Follow doctor guidance on restarting metformin if suspended.

Report & Digital Images

• Written reports are delivered within a few hours to the same day.
• Request digital DICOM images on CD/USB for your cardiologist’s review alongside the printed report.

The 6 Most Common Reasons Scans Get Rescheduled

Every single one of these causes a wasted day — and every single one is 100% preventable:

  • ❌ No recent kidney function (eGFR) report
  • ❌ High heart rate due to morning tea/coffee
  • ❌ Not fasted as instructed
  • ❌ Missing original doctor referral letter
  • ❌ Undisclosed PDE5 inhibitor medication
  • ❌ Arriving late, bypassing prep window

Where to Get CT Coronary Angiography in Varanasi

Karauli Diagnostics operates 4 advanced centres across Varanasi equipped with 384-slice CT scanners:

Bhojubeer Branch

S.2/326 E-3A, Plot No. 18/1, Gilat Bazar, Bhojubeer, Varanasi, Uttar Pradesh – 221002

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Sankat Mochan Branch

B. 36/4-27, Ramapuri Colony, Near Sankat Mochan Temple, Saket Nagar Colony, Varanasi, Uttar Pradesh – 221005

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Manduadih Branch

Shop No. 1, MS Commercial Complex, Manduadih Varanasi, Uttar Pradesh – 221005

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Maldahiya Branch

C21/30, A1-A2 Pishachmochan Road Near Ganga Palace Maldhaiya, Varanasi, Uttar Pradesh – 221002

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Awaleshpur Branch

Amra Chauraha, Above Grihasthi Supermarket, Varanasi – 221106

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Frequently Asked Questions

Everything you need to know about CT coronary angiography preparation and protocols:

Commonly around four hours before the appointment, though protocols vary. Confirm the exact duration when you book. Water is usually permitted and being well hydrated is generally helpful — check with the team.
Caffeine raises heart rate. Cardiac CT produces its clearest images at a steady, relatively low heart rate, so caffeine can degrade image quality or mean you need additional heart-rate medication before the scan. Avoid tea, coffee, cola, energy drinks and green tea as directed.
Do not stop any medication on your own. Depending on your kidney function, your doctor may advise suspending metformin for around 48 hours after contrast. Bring your kidney function report and your medication list so the referring doctor and the scan team can decide.
Possibly. If your heart rate is above the target range on arrival, a beta blocker may be given orally or through the IV. This is routine and is the main reason the appointment takes longer than the scan itself.
Most people feel a spreading warmth through the body and a metallic taste in the mouth. Many describe a sensation of having wet themselves — this does not actually happen. Both effects are normal and pass within seconds.
Plan for one to two hours including registration, assessment, heart-rate preparation and post-scan observation. The scan acquisition itself takes only seconds.
Not medically — there is no sedation and you can drive yourself home. Company is helpful if you are elderly, anxious or travelling from outside the city.
Yes. There is no recovery period. Drink plenty of water for the rest of the day to help clear the contrast, unless your doctor has restricted your fluids.
Imaging reports are typically delivered within a few hours to the same day depending on complexity. Confirm the expected turnaround when you book, and ask for digital images as well as the printed report.
Tell the team when you book. A nitrate spray may be given before the scan to widen the coronary arteries, and combining nitrates with sildenafil, tadalafil or vardenafil can cause a dangerous fall in blood pressure. These medicines are generally avoided for at least 48 hours before the scan. This information is confidential and medically necessary.
AS

Medically Reviewed by Dr. Ankita Ujjwal Shah (MD, DNB)

Consultant Radiologist, Karauli Diagnostics · Published: 1 August 2026

This guide is for informational purposes and does not replace specific orders from your physician or scanning team.

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