MRI scans are coming soon to Lola Health. We are not taking bookings yet. In the meantime, you can book an at-home blood test, with a phlebotomist visit included.
MRI, CT, and ultrasound are the three main imaging methods used in the UK. Each works differently, costs differently, and is better suited to different clinical questions. This guide explains when you need each one, what they cost, and how to choose the right scan for your situation.
Quick Comparison: MRI vs CT vs Ultrasound
| Feature | MRI | CT | Ultrasound |
|---|---|---|---|
| How it works | Magnetic fields + radio waves | X-ray beams from multiple angles | High-frequency sound waves |
| Radiation | None | Yes (ionising radiation) | None |
| Private cost (UK) | Varies by body area | £300–£600 | £100–£300 |
| Scan duration | 20–60 minutes | 5–15 minutes | 15–30 minutes |
| Best for | Soft tissue, brain, joints, organs | Bones, chest, acute trauma, some cancers | Pregnancy, gallbladder, thyroid, superficial structures |
| Contrast agent | Gadolinium (sometimes) | Iodine-based (often) | Rarely needed |
| Claustrophobia risk | Yes (enclosed scanner) | Low (quick, open ring) | None |
| Noise level | Loud (headphones needed) | Quiet | Silent |
When MRI Is the Right Choice
MRI excels at imaging soft tissue — anything that isn't bone. Choose MRI when you need to see:
Brain and Neurological
- Persistent headaches, migraines, dizziness — Brain MRI
- Suspected MS, stroke follow-up, brain tumours
- Pituitary abnormalities (hormone issues) — Pituitary MRI
Joints and Musculoskeletal
- Knee ligament tears, meniscus damage — Knee MRI
- Shoulder rotator cuff tears, labral tears — Shoulder MRI
- Disc herniation, spinal stenosis — Lumbar Spine MRI
- Hip labral tears, avascular necrosis — Hip MRI
Organs
- Liver disease, fatty liver, liver lesions — Liver MRI
- Kidney masses or cysts — Kidney MRI
- Prostate cancer assessment (mpMRI) — Prostate MRI
- Heart muscle disease (cardiomyopathy) — Cardiac MRI
Cancer Screening
- Pelvic masses, ovarian cysts — Pelvis MRI
- Full body screening — Full Body MRI
When CT Is the Right Choice
CT scans are faster and better for certain structures. Choose CT when:
- Acute trauma — Suspected fractures, head injuries, internal bleeding. CT is fast (5–10 minutes) and available in every A&E.
- Chest imaging — Lung cancer screening, pulmonary embolism, pneumonia assessment. CT of the chest is better than MRI for lung tissue.
- Bone detail — Complex fractures, bone tumours, spinal fractures. CT shows bone structure in higher resolution than MRI.
- Abdominal emergencies — Appendicitis, bowel obstruction, kidney stones. CT is the standard emergency imaging for acute abdominal pain.
- Vascular imaging — CT angiography (CTA) for aortic aneurysm, pulmonary embolism, coronary artery disease. Fast and accurate for blood vessel imaging.
Downside: CT uses ionising radiation. A single CT scan delivers the equivalent of 6–12 months of background radiation. This makes CT less suitable for repeated monitoring or screening in younger patients.
When Ultrasound Is the Right Choice
Ultrasound is cheap, radiation-free, and excellent for certain applications. Choose ultrasound when:
- Pregnancy monitoring — Standard for fetal assessment. Safe, radiation-free, real-time imaging.
- Gallbladder — Gallstones, cholecystitis. Ultrasound is the first-line test.
- Thyroid nodules — Initial assessment. If the ultrasound shows a suspicious nodule, a thyroid MRI can provide more detail.
- Superficial lumps — Breast lumps, lymph nodes, hernias. Quick, painless assessment.
- Kidney stones — Visible on ultrasound without radiation.
- Heart valves (echocardiogram) — Functional cardiac assessment. Different from cardiac MRI, which looks at heart muscle.
Downsides: Limited by body habitus (harder in larger patients), operator-dependent (quality varies with the sonographer's skill), and can't image through bone or air-filled structures.
Can You Have More Than One Type?
Yes — they're often complementary:
- Ultrasound → MRI: A thyroid ultrasound showing a nodule may prompt a thyroid MRI for more detail.
- CT → MRI: A CT showing a liver lesion may need MRI for characterisation (MRI can distinguish benign from malignant liver lesions better than CT).
- Blood test → MRI: Abnormal blood results (raised liver enzymes, high PSA, elevated CA-125) can direct you to the right MRI scan. Read our guide on when blood tests suggest you need a scan.
Cost Comparison
| Scan Type | Private Cost (UK) | Best For |
|---|---|---|
| Ultrasound | £100–£300 | First-line for superficial structures, pregnancy, gallbladder |
| MRI (individual) | Varies by body area | Soft tissue, brain, joints, organs, cancer screening |
| CT scan | £300–£600 | Bones, chest, acute trauma, vascular |
| Full body MRI | Varies by provider and protocol | Preventive whole-body screening |
Decision Flowchart
Not sure which scan you need? Follow this logic:
- Is it an emergency? → Go to A&E. They'll order the right scan (usually CT).
- Is it a pregnancy or gallbladder question? → Start with ultrasound.
- Is it a bone/fracture question? → X-ray first, then CT if needed.
- Is it a joint, brain, organ, or soft tissue question? → MRI is almost always the best option.
- Not sure what's wrong? → Start with a blood test to narrow it down. If your results point to a problem, an MRI may be the next step. MRI scans are coming soon to Lola Health — your GP can also refer you.
Start with a Blood Test — Peak 70 Panel
70 biomarkers covering liver, kidney, thyroid, hormones, inflammation, and more. Results in 2 working days.
View Blood Test Details →Related Guides
- Private MRI Scan Cost UK (2026)
- MRI Scan Cost by Body Part
- When Blood Tests Suggest You Need a Scan
- Blood Test Then Scan: Complete Pathway
At-Home Blood Testing
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