Triphase CT Abdomen

What is a Triphasic CT Scan Abdomen?

A triphasic CT abdomen is a specialised CT scan that captures three distinct “phases” of blood flow through your abdominal organs after an iodine-based contrast injection. Each phase highlights different blood vessels and tissue characteristics, giving doctors a dynamic view impossible to obtain with routine imaging.

How It Differs from Routine CT

• Routine CT: Single-phase image—good for general anatomy.
• Triphasic CT: Three timed phases—arterial, portal venous, and delayed—pinpointing tiny tumours, vascular invasion, or subtle lesions.

Triple-Phase Imaging Explained

1. Arterial Phase (20–25 s): Highlights arteries and hypervascular tumours.
2. Portal Venous Phase (60–70 s): Shows organ parenchyma and venous drainage.
3. Delayed Phase (3–5 min): Detects contrast wash-out patterns, scarring, or leaks.

Radiation & Safety Profile

• Effective dose: ~5–8 mSv (similar to 1–2 years of natural background).
• ALARA principle: Lowest dose achievable with iterative reconstruction software.
• Contrast: Non-ionic, low-osmolar to reduce allergy risk.

Standard Triphasic Liver Protocol

• Arterial, portal venous, and 3-minute delayed phases centred on liver.

Modified Triple-Phase for Kidneys

• Corticomedullary, nephrographic, and excretory phases to map renal masses and collecting-system anatomy.

• Arterial Phase Findings: Arterial enhancement, hypervascular foci.
• Portal Venous Phase Findings: Lesion wash-out, venous thrombus.
• Delayed Phase Findings: Capsular retraction, contrast pooling.

• Detect hypervascular tumours before symptoms appear.
• Assess vascular invasion (portal vein, renal vein).
• Guide surgical planning with 3-D vascular mapping.

Liver Lesion Characterisation

• Distinguish benign haemangioma from hepatocellular carcinoma (HCC).
• Detect tiny hypervascular metastases.

Pancreatic & Renal Mass Work-up

• Evaluate renal cell carcinoma (RCC) extension into veins.
• Stage pancreatic neuroendocrine tumours.

Follow-up After Treatment

• Post-chemoembolisation or post-surgery assessment of residual tumour.

• Sub-millimetre resolution: 128-slice CT with 0.625 mm slices.
• Same-day reporting: Radiologists on-site until 9 p.m.
• Transparent pricing: No hidden contrast or film charges.

• Hepatocellular carcinoma (HCC)
• Renal cell carcinoma (RCC)
• Neuroendocrine tumours (NETs)

Fasting & Hydration Guidelines

• Fast 4–6 h before scan.
• Drink 500 mL water up to 1 h prior to aid contrast excretion.

Medication Adjustments

• Metformin: Pause 48 h post-scan if eGFR <60.
• Diabetes: Morning slots preferred for better glycaemic control.

• Recent creatinine report (within 4 weeks).
• Contrast consent form signed after allergy & renal screening.

• Morning slots for diabetic patients to minimise fasting hypoglycaemia.
• Emergency 24/7 availability for acute abdominal pain or trauma.

• Adults & seniors: No upper age limit.
• Pediatric considerations: Tailored low-dose protocols for >5 years; younger children may require anaesthesia.

1. Check-in & vitals (10 min).
2. IV cannula insertion (18–20 G) in antecubital vein.
3. Positioning on CT table, arms above head.
4. Contrast injection (100–120 mL at 4–5 mL/s) with automated injector.
5. Three-phase scanning (total 5–7 min).
6. Post-scan observation (15 min for delayed reactions).

• Pregnancy screening: Urine β-hCG for women 12–50 years.
• Claustrophobia support: Open-bore CT & mild sedation on request.

Contrast Allergy Precautions

• Mild reactions: rash, nausea (1–3 %).
• Severe anaphylaxis (<0.04 %).
• Pre-medication available for prior allergy.

Renal Function Requirements

• Serum creatinine ≤1.5 mg/dL (or eGFR ≥45).
• Hydration protocol for borderline values.