If you’re experiencing pain in the middle of your tummy or your lower right side, you may be concerned that you have the symptoms of appendicitis. Magnetic Resonance Imaging (MRI) scans accurately confirm and exclude acute appendicitis in adults and children.
We’ll guide you through the symptoms of appendicitis, what it looks like on MRI and what else could be causing your painful symptoms so you can feel reassured you’re taking the right course of action.
What is Appendicitis?
Appendicitis is when the appendix, a small tubular pouch attached to the large intestine within the bowel, becomes suddenly and intensely inflamed (acute appendicitis), causing swelling and infection. Appendicitis is one of the most common reasons people need emergency surgery, especially young adults and children, although it can happen at any age.
Inflammation caused by appendicitis can cause the appendix to swell and burst, releasing bacteria from the bowels into the abdominal cavity. It can then travel into the bloodstream, which can lead to sepsis. This risk is why doctors will usually remove the appendix (appendectomy) before it bursts. Experts classify appendicitis into uncomplicated (non-perforating) or complicated (perforating) based on how severe the infection is and whether the appendix is showing signs of perforation or rupture.
What Are the Symptoms of Appendicitis?
Symptoms of appendicitis can vary widely from person to person. However, the most common sign for many people is pain in the tummy (abdomen), which usually starts in the middle of the belly and moves to the lower right-hand side within a day or two. The pain often worsens with movement, such as coughing or driving over uneven ground.
However, not everyone presents with pain, which can sometimes make the condition trickier to diagnose. Children, for example, may feel tenderness throughout their body instead of in the abdomen, while older people may not feel as much pain but may feel confusion and shock.
Apart from pain, there are other symptoms of appendicitis to be aware of:
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Fever
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Tiredness
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Lack of appetite or refusal to eat
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Swelling or bloating in the abdomen
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Nausea and vomiting
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Bowel problems, such as constipation or diarrhoea
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Pelvic or groin pain
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Chest pain
Can an MRI Detect Appendicitis?
An MRI is a valuable tool in detecting appendicitis, with studies suggesting that they have a diagnostic accuracy of between 95% (2021) and 100% (2023). While computed tomography scans (CT scans) and ultrasound scans are the imaging techniques most commonly used to detect appendicitis, MRI can be an ideal alternative imaging technique for children and pregnant women, where radiation from CT scans can be a risk. In pregnancy, MRI can also differentiate between appendicitis and other pregnancy conditions that have similar symptoms, such as ovarian torsion or pelvic inflammatory disease.
MRI is also useful for distinguishing between perforated and non-perforated appendicitis, which can be critical information for managing the condition.
What Does Appendicitis Look Like on MRI
The results from an MRI show similar signs to other imaging methods, such as CT scans or ultrasounds.
MRI will show any swelling and widening of the appendix, so the tubular organ may look wider than usual and feature a defined and bright border where inflammation causes a thickening of its walls. Fluid around the appendix caused by infection or perforation would appear as darker areas near the organ.
How Will My Doctor Approach the Diagnosis of Acute Appendicitis?
Patient History Evaluation
If they think you have suspected appendicitis, your doctor will ask about your symptoms and your medical history. They will ask about the type of pain you are experiencing and how long it has lasted. They’ll ask if you've had episodes of pain in the past and whether you have any gastrointestinal symptoms, such as diarrhoea or constipation. They will also ask if you’ve had abdominal surgery in the past.
Physical Examination
Your clinician will check for swelling and tenderness around the stomach and the right lower side of the abdomen. They will take your temperature and check for facial flushing, which may indicate fever. They’ll also check your tongue and breath for signs of dehydration.
There are also physical tests that your doctor will use to help them diagnose acute appendicitis, such as:
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Rovsing's sign: This test checks for pain in the right lower quadrant of the abdomen (where the appendix is) when pressure is applied to the left lower quadrant. If pressing on the left side causes pain on the right side, it may suggest appendicitis because it indicates irritation or inflammation of the appendix.
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Psoas sign: This test checks for pain when your doctor extends and stretches the right thigh while lying on your left side. If this causes pain in the right lower abdomen, it may indicate that the appendix is inflamed and irritating the psoas muscle near the appendix.
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Obturator sign: This test involves moving the right thigh inward (rotating it while it's bent) and checking for pain in the right lower abdomen. Pain during this movement can suggest inflammation in the appendix, affecting nearby muscles, including the obturator.
If you’re pregnant, your doctor may also recommend a gynaecological and pelvic examination to rule out other possible conditions, such as ectopic pregnancy.
Men and women may be offered a groin examination to rule out alternative conditions, such as a hernia, while men may be offered a scrotal examination to rule out testicular problems.
Blood Tests (Check for Infection or Inflammation)
Your doctor will recommend blood tests to check for signs of inflammation or infection. A complete blood count (CBC) will show increased white blood cells, a sign of appendicitis. High levels of C-reactive protein (CRP) can also suggest inflammation.
Urinalysis (Rule Out Urinary Tract Issues)
A urine test will help to rule out a urinary tract infection (UTI) or another kidney problem that could be causing your symptoms. Blood or pus in your urine could indicate a UTI.
CT Scan
A CT scan is often the first scan doctors use to identify appendicitis, especially in adults and non-pregnant women. CT scans provide detailed images of the abdomen and pelvis and allow your clinicians to see the appendix and any related problems, such as perforation or infection.
MRI
MRI is particularly helpful for pregnant women and children as it avoids the risk of radiation exposure from a CT scan/ Your doctor may recommend an MRI if they think a CT scan or an ultrasound may be unsuitable for you.
Ultrasound
Ultrasound is often used in children and pregnant women because it doesn't use radiation and can show the appendix and any signs of inflammation or infection. However, if you are obese or you have gas in the intestines, it can make the appendix harder to see on ultrasound.
Abdominal X-Ray (If Needed)
X-ray isn’t usually used to diagnose appendicitis, but it can rule out other conditions, such as bowel blockages or ruptures.
Pregnancy Test (For Women of Childbearing Age)
If there’s a possibility you could be pregnant, your doctor will offer you a pregnancy test. It’s an important test because it can help to rule out the possibility of an ectopic pregnancy.
Diagnostic Laparoscopy (If Uncertain Diagnosis)
If doctors are still unsure whether you have appendicitis, they may recommend diagnostic laparoscopy. It involves a small incision in the abdomen, under general anaesthetic, and the insertion of a laparoscope, a thin tube with a light and a camera. This will allow your surgeon to carefully examine the appendix and surrounding organs. It is considered minimally invasive, and your incision will be closed with stitches or adhesive strips after the laparoscopy.
If It’s Not Appendicitis, What Else Could It Be?
There are lots of other conditions which may present with similar symptoms to acute appendicitis, including, but not limited to:
Gastrointestinal conditions:
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Gastroenteritis
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Incarcerated hernia
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Perforated peptic ulcer
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Pancreatitis
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Inflammatory bowel disease
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Irritable bowel syndrome
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Constipation
Urological conditions:
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Urinary tract infection
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Urinary retention
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Testicular torsion
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Ectopic pregnancy
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Pelvic inflammatory disease
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Endometriosis or adenomyosis
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Fibroids
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Period pain
Other conditions:
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Pneumonia
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Radicular back pain or lumbar discitis
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Non-specific abdominal pain
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Abdominal wall abscess or haematoma
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Shingles
Causes of Appendicitis
Doctors don’t fully understand what causes acute appendicitis, but we think about half of all cases are caused by a blockage in the appendix. When the appendix is blocked, it becomes swollen due to mucus, bacterial growth and inflammation. Thai reduces blood flow to the appendix, which can lead to tissue death (necrosis) and, in some cases, the appendix bursting. Blockages may be due to:
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A buildup of hard stool
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Lymph tissue swelling, often from infection
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Foreign bodies or objects in the appendix
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Tumours (in rare cases, a tumour in the appendix itself).
Certain factors can increase the risk of appendicitis, including:
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Family history of appendicitis
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Seasonal trends (appendicitis happens more often in the summer)
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Infection, for example, from E. coli
What’s The Treatment And Outlook For Appendicitis?
Appendicitis is usually treated by removing the appendix during surgery (appendectomy). It usually takes around an hour and is performed under general anaesthetic. In some cases, if the infection is caught early and surgery is considered too risky, your doctor may recommend antibiotics instead.
Most people recover from appendicitis in 1 to 2 weeks, although recovery can take longer if the appendix bursts before removal. It’s common to have pain around the wounds and some bowel problems, such as constipation or diarrhoea, while you heal. If you have keyhole surgery, it may be possible to go home the next day, while open surgery needs a longer hospital stay.
You can't get appendicitis again after having your appendix removed. However, in very rare cases, a condition called residual appendicitis can happen if small pieces of the appendix are left behind during surgery.
Are There Any Complications From Appendicitis?
If your appendix is perforated, there is a risk of more severe complications, such as:
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An appendix mass, where the inflamed appendix forms a lump surrounded by other tissues.
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An appendix abscess, which may form after the mass.
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Generalised peritonitis, a dangerous infection caused by leakage from the appendix.
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Sepsis, which affects 17–32% of patients with perforated appendicitis.
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Bowel obstruction, often due to adhesions formed in the abdomen.
In pregnant women, complications can include a higher risk of miscarriage or premature birth.
Perforated appendixes affect between 16% and 40% of people with appendicitis (2024), and the risk rises in children and older people.
Why an MRI Scan is a Good Option
MRI is a safe way to check for appendicitis because it can offer clinicians a view of your abdomen and groin without the risk of radiation exposure, making it particularly helpful for pregnant women and children. However, it can be more expensive and only sometimes available, and some people find the scanner uncomfortable.
How an MRI Scan Detects Appendicitis
MRI scans use strong magnetic fields and radio waves to create detailed images of your abdomen, helping to detect signs of appendicitis.
The process begins by aligning water molecules in the tissues using magnets. Radio waves briefly disrupt this alignment, and as the molecules return to their original position, they send out signals that the MRI machine captures.
A computer processes these signals to create detailed images, slice by slice, allowing doctors to see the appendix and any signs of inflammation, swelling, or complications, such as an abscess or perforation.
Find an MRI Scan for Appendicitis
If you’re not sure whether your symptoms are signs of appendicitis, an MRI can help diagnose the condition and guide your treatment options. Whether you need surgery, antibiotics, or monitoring, an MRI provides important information to help manage your care. If you're unsure whether an MRI is the right choice for you, our team of expert clinicians can help you understand your options and determine the best steps to improve your health and reduce the risk of complications. However, call 999 or go to A&E if you have severe pain in your abdomen or signs of sepsis.
Sources:
Acute appendicitis. (2024). https://radiopaedia.org/articles/acute-appendicitis-2?lang=gb
Appendicitis. (2024). https://www.nhs.uk/conditions/appendicitis/
Appendicitis. (2024). https://cks.nice.org.uk/topics/appendicitis/
Appendicitis. (2023).https://my.clevelandclinic.org/health/diseases/8095-appendicitis
Dongchan K., et al. (2023). Rapid MRI Abdomen for Assessment of Clinically Suspected Acute Appendicitis in the General Adult Population: a Systematic Review. https://www.sciencedirect.com/science/article/pii/S1091255X23004171?via%3Dihub
D'Souza N., et al. (2021). Magnetic resonance imaging (MRI) for diagnosis of acute appendicitis. https://pmc.ncbi.nlm.nih.gov/articles/PMC8670723/
Rosenbaum, D. G., et al. (2017). Differentiating perforated from non-perforated appendicitis on contrast-enhanced magnetic resonance imaging. https://scite.ai/reports/differentiating-perforated-from-non-perforated-appendicitis-4LDzJew
