CT Scan for Kidney Stones: Fast, Accurate Diagnosis When You Need It

At Independent Physicians Medical Center (IPMC) in Northeast Philadelphia, we offer rapid CT imaging for kidney stone evaluation, helping you and your doctor get answers fast so treatment can begin without delay.

Why Is CT the Gold Standard for Kidney Stones?

A non-contrast CT scan of the abdomen and pelvis (meaning no IV dye is needed) is the gold standard for kidney stone detection. Here’s why it’s so effective:

Extremely high accuracy. CT can detect kidney stones with greater than 95 percent sensitivity, regardless of the stone’s chemical composition. Unlike X-rays, which can only detect calcium-based stones (and miss uric acid and other types), CT identifies virtually all stones.

Precise location. CT shows exactly where the stone is — whether it’s still in the kidney, has moved into the ureter (the tube connecting the kidney to the bladder), or is in the bladder. The stone’s location determines the treatment approach.

Size measurement. The exact size of the stone is documented. Small stones (under 5 mm) often pass on their own, while larger stones may require intervention.

Obstruction assessment. CT reveals whether the stone is blocking urine flow, which can cause the kidney to swell (hydronephrosis). Obstructing stones, especially those causing severe hydronephrosis or infection, may require urgent treatment.

Alternative diagnoses. When kidney stones are NOT found, the CT scan may reveal another cause for your pain — such as appendicitis, diverticulitis, an ovarian cyst, or an aortic aneurysm. This is one of the reasons CT is so valuable in the acute setting.

Speed. The scan takes just a few minutes and requires no preparation, contrast dye, or fasting, making it ideal for patients in acute pain.

What to Expect During the Scan

A CT scan for kidney stones is one of the simplest imaging exams. No fasting, no IV, no contrast dye, and no special preparation are needed. You’ll lie on a table that slides through the scanner, and the scan is completed in just a few minutes. You may be asked to hold your breath briefly.

The scan is painless (though you may be in significant pain from the stone itself — our team will help ensure your comfort).

Understanding Your Results

A board-certified radiologist will review the images and identify any stones present, documenting their size (in millimeters), location (kidney, ureter, or bladder), and whether they are causing obstruction. The radiologist will also assess for signs of infection and evaluate the other abdominal organs for alternative diagnoses.

Based on the findings, your doctor may recommend watchful waiting and pain management for small stones that are likely to pass on their own, medication to help the stone pass more easily (medical expulsive therapy), extracorporeal shock wave lithotripsy (ESWL) to break up larger stones from outside the body, ureteroscopy (a minimally invasive procedure to remove or fragment the stone), or surgical intervention for very large or complicated stones.

At IPMC, we prioritize fast results so your treatment can begin as quickly as possible.