Which type of kidney stone is typically not visible on a CT scan?

The type of kidney stone that is typically not visible on a CT scan is uric acid. This stone is composed primarily of uric acid, which is less dense than other types of stones. As a result, uric acid stones may not show up on standard imaging techniques, such as non-contrast CT scans, particularly when compared to the more dense calcium-containing stones.

Uric acid stones form in acidic urine and can be the result of factors such as dehydration or certain metabolic disorders. Since they are not radiopaque, they may only be detected through other means, such as ultrasound or through the identification of urinary crystals. This distinction is significant as it impacts the diagnostic approach and potential treatment for patients suspected of having kidney stones.

In contrast, struvite stones, calcium oxalate stones, and cystine stones are all typically visible on CT scans due to their dense composition, allowing for easier identification and diagnosis.