Ultrasound or MRI: what are the examinations suited for in musculoskeletal problems?

Ultrasound creates images using sound waves and is performed with a handheld probe against the skin. The examination is dynamic and can therefore show structures in motion. It uses no radiation and no contrast fluid [1][2].

MRI uses strong magnets and requires you to lie inside a scanner. The examination usually takes 15 to 25 minutes, and you must fill in a checklist beforehand [1][2].

The two examinations complement each other. Which one is relevant depends on which structure is being examined and what the answer is going to be used for [1][2].

The guideline describes ultrasound as well suited to structures near the surface, such as tendons, bursae, some ligaments and peripheral nerves. The method is inexpensive and can be performed by the clinician, but the result depends on the person performing the examination [1].

Ultrasound does not show structures inside the joint, and covers only a small area at a time. It does not show bone marrow either [1][2].

According to the guideline, MRI is best suited to cartilage, ligaments, tendons, other soft tissue in and around the joints, and bone marrow [1]. It also shows larger and deeper areas, and structures inside the joint [2].

MRI is more demanding to carry out than ultrasound and does not give the same level of detail in very superficial structures [2].

The starting point is the history and a clinical examination. The guideline says that imaging should be considered only when three conditions are met: the examination provides clinically important information beyond what the conversation and examination have given, the information can change how the problem is managed, and the changed management has a reasonable likelihood of improving the patient's health [1].

The guideline also points out that a good clinical examination and dialogue with the patient can replace imaging when it would give no benefit [1]. The guideline was published in 2014 and applies to adults with non-traumatic problems, that is, problems without a clear injury event [1].

The guideline goes through different parts of the body. Some examples:

• Back: imaging is not recommended for acute or subacute low back pain. With red flags, or symptoms that do not improve after 4 to 6 weeks, imaging is recommended, and MRI is the first choice [1].
• Shoulder: subacromial impingement syndrome and frozen shoulder are regarded as clinical diagnoses, and imaging is not recommended. When a full-thickness rotator cuff tear is suspected in people over 60 with reduced strength, ultrasound or MRI can be used [1].
• Hand and wrist: imaging is not recommended in the primary assessment of tendinopathies, ganglion cysts and trigger finger [1].
• Knee: MRI is recommended if X-ray does not explain the symptoms and significant damage to soft tissue, cartilage or bone marrow is suspected, or when a meniscal injury that needs treatment is suspected [1].

For carpal tunnel syndrome, the guideline mentions nerve conduction testing as relevant instead of imaging, and ultrasound as a good support [1]. A more recent review of American guidelines does not recommend MRI for this condition, and mentions ultrasound as an alternative when a clinical test is negative but suspicion is high [3]. You can read more in the article on carpal tunnel syndrome.

The guideline describes suspected cauda equina as an emergency, and red flags as a reason for imaging [1]. If you are unsure whether your symptoms are serious, you can contact your GP or an out-of-hours service.

Symptoms that do not improve, or that get worse, should be assessed again [1].

A chiropractor can take a history, carry out a clinical examination and assess whether imaging is relevant. When needed, diagnostic ultrasound can be used, and the chiropractor can refer on to imaging or a specialist. You can read more about chiropractic care at Dr.Dropin.

Is ultrasound better than MRI?

Neither is better in every situation. Ultrasound is well suited to tendons, bursae and nerves near the surface, while MRI shows structures inside the joint and in larger and deeper areas [1][2].

Do I need an MRI for back pain?

The guideline does not recommend imaging for acute or subacute low back pain. With red flags, or symptoms that do not improve after 4 to 6 weeks, it is recommended, and MRI is the first choice [1].

Does ultrasound use radiation?

No, ultrasound uses sound waves and no radiation [2]. The guideline points out that CT gives considerably more radiation than ordinary X-ray, and that CT is rarely used in primary diagnostics [1].

Can everything be seen on an ultrasound examination?

No. Ultrasound does not show structures inside the joint, covers only a small area at a time and does not show bone marrow [1][2]. Findings must also be interpreted together with the symptoms.

The article on carpal tunnel syndrome describes symptoms and assessment of a condition where ultrasound is sometimes relevant. The page on ultrasound examination tells more about the service at Dr.Dropin. You can find more articles in the overview of articles.

This article was written by Dr.Dropin Fysikalske and is based on the sources listed below. It gives general information and does not replace an examination by a healthcare professional.

The websites were accessed and read on 22 October 2026.

1. Norwegian Directorate of Health. National guideline: Imaging in non-traumatic musculoskeletal disorders (IS-1899). Published 21 January 2014. Link

2. Cleveland Clinic. When is ultrasound used vs. an MRI for bone, muscle and joint problems? Cleveland Clinic Health Essentials. Date not stated on the page. Link

3. Sadler KP, Torbert DR, Writer JK. Management of carpal tunnel syndrome: guidelines from the AAOS. Am Fam Physician. 2025;112(3):337-339. Link