Can X-rays detect kidney stones?

From the Guidelines

X-rays can detect kidney stones, but their sensitivity is limited, ranging from 29% to 72% for stones of various sizes and locations, as reported in the most recent study 1. When considering the detection of kidney stones, it's essential to weigh the benefits and limitations of different imaging modalities. X-rays, particularly KUB radiographs, can identify kidney stones, but their effectiveness depends on factors such as stone composition, size, and location.

• The sensitivity of X-rays for detecting kidney stones is influenced by stone characteristics, with larger stones (>5 mm) being more detectable than smaller ones.
• X-rays may miss stones that are radiolucent, such as uric acid stones, or those obscured by intestinal contents or bone.
• The choice of imaging modality depends on various factors, including patient symptoms, medical history, and previous stone episodes. According to the most recent study 1, digital radiography has been shown to be 72% sensitive for large (>5 mm) stones in the proximal ureter but only 29% sensitive overall for the detection of stones of any size in any location. In comparison, CT scans without contrast are generally preferred for their high sensitivity (over 95%) in detecting kidney stones of all types, regardless of composition, and providing valuable information on stone size, location, and potential blockages 1. Ultrasound is another option that avoids radiation exposure, making it suitable for pregnant women and children, although it is less sensitive than CT scans. Ultimately, the selection of imaging modality should prioritize the patient's specific needs and circumstances, taking into account the potential benefits and limitations of each option.

From the Research

Detection of Kidney Stones using X-rays

• X-rays can be used to detect kidney stones, but their sensitivity is lower compared to other imaging modalities like CT scans 2, 3.
• The sensitivity of plain abdominal x-ray for detecting kidney stones is around 48% 3, which means that not all kidney stones may be visible on an x-ray.
• The size and location of the stone can affect its visibility on an x-ray, with larger stones being more easily detectable 3.
• X-rays are still recommended for follow-up of renal stones, particularly for patients with radiopaque stones 2, 3.

Comparison with Other Imaging Modalities

• CT scans are considered the gold standard for evaluating urinary stones, providing information on stone composition, size, burden, location, and collecting system 2.
• CT scans have a higher sensitivity for detecting kidney stones compared to x-rays, but they also expose patients to higher radiation doses 2.
• Ultrasound is another non-invasive modality that can be used to detect kidney stones, but its sensitivity is lower compared to CT scans 2.

Clinical Implications

• The choice of imaging modality for detecting kidney stones depends on various factors, including the patient's symptoms, medical history, and the suspected location and size of the stone 2, 3.
• X-rays may be used as a initial screening test for kidney stones, but CT scans or other imaging modalities may be necessary to confirm the diagnosis and plan treatment 2, 3.