🔬 Men's Health
CT Scan Explained in Nigeria
What a CT scan shows, what to expect, and how to prepare in Nigeria
A CT scan (computed tomography) uses X-rays taken from multiple angles, processed by a computer to create detailed cross-sectional images of the body. CT provides much more detailed information than a plain X-ray — showing bones, soft tissues, blood vessels, and organs in three-dimensional detail. In Nigeria, CT scanners are available at most state tertiary hospitals and many private hospitals. Understanding what your CT scan involves — including preparation, contrast dye, radiation, and what the report means — reduces anxiety and helps you prepare appropriately.
Signs and Symptoms
✓ CT is ordered for: head injury/stroke assessment, chest conditions (pneumonia, pulmonary embolism, lung cancer screening), abdominal/pelvic emergencies (appendicitis, bowel obstruction, aortic aneurysm), trauma assessment, cancer staging, spinal problems
✓ CT involves X-ray radiation — significantly more than a plain X-ray. Not used routinely where ultrasound or MRI can answer the clinical question
✓ CT is rapid (5–10 minutes) — preferred over MRI in emergencies
When to Seek Help
Head injury with loss of consciousness or neurological symptomsUrgent CT head to exclude intracranial haemorrhage
Sudden severe headache ('thunderclap headache')CT head within 6 hours — subarachnoid haemorrhage. If CT negative, lumbar puncture needed
Stroke symptoms — FAST (Face, Arm, Speech, Time)Emergency CT head distinguishes ischaemic from haemorrhagic stroke — determines treatment
Chest pain with breathlessness in a hospitalised patientCT pulmonary angiography (CTPA) for pulmonary embolism — time-sensitive
Tests & Diagnosis
🧪 CT head findings — key terms
Hyperdense (white): fresh blood (haemorrhage). Hypodense (dark): ischaemia/infarct, oedema, old blood. Midline shift: brain swelling pushing structures across midline — raised intracranial pressure. Subarachnoid blood: bright blood around brain surface
🧪 CT chest findings
Ground-glass opacity: hazy increased density — pneumonia, COVID, interstitial lung disease. Consolidation: denser opacity — bacterial pneumonia. Pulmonary embolism: filling defect in pulmonary artery on CTPA. Pleural effusion: fluid beside lung
🧪 CT abdomen/pelvis findings
Appendicitis: dilated appendix (> 6mm), periappendiceal fat stranding. Diverticulitis: thickened sigmoid colon with pericolic fat stranding. Bowel obstruction: dilated loops of bowel with transition point
🧪 CT spine
Disc herniation, spinal canal stenosis, fractures, tumour, infection (osteomyelitis). More detailed for bony structures than MRI
🧪 Hounsfield units (HU)
The numerical scale of CT density. Air: -1000. Fat: -100. Water: 0. Blood: +50–80. Bone: +400+. These numbers appear on CT reports and guide diagnosis
Frequently Asked Questions
Is CT radiation dangerous?
The radiation from a single CT scan increases lifetime cancer risk by approximately 0.05% above background. This is a very small risk. For a clinically indicated CT (suspected stroke, trauma, cancer staging), the risk from not having the scan (missing a treatable diagnosis) far exceeds the radiation risk. Concern about radiation should not delay clinically urgent CT.
Why does the radiologist want to give me dye (contrast)?
Iodinated contrast dye injected intravenously enhances the visibility of blood vessels and the vascularity of organs and tumours, making many conditions much clearer. A 'plain CT' (without contrast) may miss blood vessel problems, some tumours, and infection. Many scans are done both without and then with contrast (biphasic) for maximum information.
Can I have a CT if I have kidney disease?
Contrast CT carries risk of contrast-induced nephropathy (worsening kidney function) in people with eGFR < 30 mL/min. This must be weighed against the clinical need. For urgent clinical situations, CT is performed with adequate pre-hydration. For non-urgent situations, alternative imaging (MRI without gadolinium, ultrasound) should be considered.
How long does a CT scan take?
The scan itself takes 5–15 minutes. However, total time at the imaging centre may be 1–2 hours including preparation, waiting for the machine, changing, and waiting for post-scan observation after contrast. Results (a written radiologist's report) are usually available within 1–24 hours depending on urgency.