A right upper quadrant (RUQ) ultrasound is an imaging scan that uses sound waves to examine the organs in the upper right portion of your abdomen, primarily the liver, gallbladder, bile ducts, and right kidney. It’s the recommended first-line imaging test for evaluating pain in that area, most often ordered to check for gallstones or gallbladder inflammation.
What It’s Used For
The most common reason for an RUQ ultrasound is acute pain in the upper right side of the abdomen. That pain is most frequently caused by gallbladder or liver problems. The American College of Radiology identifies ultrasound as the main imaging modality for assessing this type of pain, and it’s considered the go-to choice when a gallbladder disorder is suspected.
Specific conditions this scan helps detect include:
- Gallstones (solid deposits in the gallbladder)
- Cholecystitis (inflammation of the gallbladder, often caused by a trapped gallstone)
- Bile duct stones (gallstones that have moved into the ducts draining the liver)
- Liver abnormalities such as fatty liver disease, cysts, or masses
- Kidney issues on the right side, including stones or blockages
Your doctor may also order this scan to investigate abnormal liver blood tests, unexplained jaundice (yellowing of the skin or eyes), or fluid buildup in the abdomen.
Why Ultrasound Over CT
Ultrasound and CT scans each have strengths in this part of the body, but ultrasound comes first for good reason. It’s significantly better at finding gallstones: ultrasound detects them about 87% of the time, compared to just 60% for CT. Gallstones are the most common cause of RUQ pain, so this advantage matters.
CT does outperform ultrasound for diagnosing gallbladder inflammation itself (92% sensitivity versus 79%), which is why your doctor may order a CT or other follow-up imaging if your ultrasound looks normal but your symptoms strongly suggest inflammation. Still, ultrasound is the starting point because it’s fast, widely available, involves no radiation, and catches the most likely culprit.
What the Scan Looks For
The sonographer and radiologist are evaluating several things at once. For the gallbladder, the key findings are whether stones are present, whether the gallbladder wall is thickened, and whether there’s fluid collecting around the gallbladder (called pericholecystic fluid). A thickened gallbladder wall is the most reliably reported sign of gallbladder inflammation on ultrasound. When fluid is present around the gallbladder, the wall is almost always thickened too, so wall thickness serves as the primary marker.
These findings also have practical implications beyond diagnosis. A thickened gallbladder wall on ultrasound is about four times more likely to indicate a complicated surgical case if gallbladder removal becomes necessary. This helps surgeons plan appropriately before they operate.
For the liver, the scan can reveal changes in size, texture, or the presence of masses. The bile ducts are checked for dilation, which could indicate a stone or blockage downstream. The right kidney is typically included in the field of view and assessed for stones, swelling, or structural problems.
How to Prepare
You’ll typically need to fast for 8 to 12 hours before the scan. This means no food or drinks during that window. Fasting serves two purposes: it reduces gas in your abdomen that can interfere with image quality, and it allows the gallbladder to fill with bile, making it easier to visualize. Many appointments are scheduled for the morning so you can fast overnight.
Ask your care team whether plain water is allowed before the test. Continue taking your regular medications unless you’re specifically told to stop.
What Happens During the Scan
The entire exam typically takes less than 30 minutes. You’ll lie on an exam table, and the sonographer will apply a warm gel to the skin over your right upper abdomen. A handheld device called a transducer is then pressed gently against the skin and moved across the area. The transducer sends sound waves into your body and captures the echoes that bounce back, creating real-time images on a screen.
You may be asked to hold your breath briefly, roll onto your side, or shift positions so the sonographer can get better views of certain structures. The gallbladder can sometimes hide behind the ribs or bowel gas, so repositioning helps. During the exam, the sonographer may press the transducer firmly into your upper abdomen and ask if you feel pain. This is a deliberate test: tenderness at that specific spot when the gallbladder is compressed by the transducer is a clinical sign of gallbladder inflammation.
The scan is painless unless there’s active inflammation, and it involves no needles, contrast dye, or radiation. Results are typically read by a radiologist and sent to your ordering physician, often within a day.
What Happens After
If the ultrasound reveals gallstones without inflammation, your doctor may recommend monitoring or discuss surgical options depending on your symptoms. If signs of acute inflammation are found, treatment decisions move faster, potentially including antibiotics and gallbladder removal.
A normal scan doesn’t always rule everything out. If your pain persists and the ultrasound is unremarkable, your doctor may order additional imaging like a CT scan or a specialized nuclear medicine scan that tracks bile flow through your system. Some conditions, like small bile duct stones or early inflammation, can be missed on an initial ultrasound.