OBJECTIVE: To assess the ability of noninvasive computed tomography (CT) scans to detect interstitial calcium phosphate deposits (Randall's plaques) and duct of Bellini plugs, which are possible stone precursor lesions.
METHODS: At time of percutaneous nephrolithotomy (PCNL) for stone removal, all accessible individual papillae of 105 patients were endoscopically visualized and video recorded. Image-processing software was used to estimate the percentage of papillary surface occupied by plaque or plug in each pole (upper, middle, lower). The location of stones was also recorded. A radiologist blinded to the mapping results scored presurgical (n = 98) and postsurgical (n = 105) abdominal CT scans for the presence or absence of calcification by pole.
RESULTS: The cohort was a mean age of 56 years (range, 23-84 years). Maximum papillary surface area of each area of the kidney occupied by plug correlated with CT calcifications on pre- and postprocedure images by rank sum test. However, maximum plaque surface area did not correlate with radiographic findings (P = .10-.90 for each pole by rank sum test). Sensitivity was 81% and specificity was 69% of CT to detect plugs of at least 1% of the papillary surface area.
CONCLUSION: Calcifications seen on current generation clinical CT scans correspond to ductal plugging involving at least 1% of the papillary surface area. Current clinical CT scan technology appears inadequate for detecting Randall's plaques.
Krambeck AE, Lieske JC, Li X, Bergstralh EJ, Rule AD, Holmes D 3rd, McCollough CM, Vrtiska TJ. Are you the author?
Department of Urology, Mayo Clinic, Rochester, MN.
Reference: Urology. 2013 Jun 20. pii: S0090-4295(13)00505-0.