Browsing by Author "Vrtiska, Terri J."

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    Phenotypic characterization of kidney stone formers by endoscopic and histological quantification of intra-renal calcification
    (Elsevier, 2013) Linnes, Michael P.; Krambeck, Amy E.; Cornell, Lynn; Williams, James C., Jr.; Korinek, Mark; Bergstralh, Eric J.; Li, Xujian; Rule, Andrew D.; McCollough, Cynthia M.; Vrtiska, Terri J.; Lieske, John; Anatomy, Cell Biology and Physiology, School of Medicine
    Interstitial Randall's plaques and collecting duct plugs are distinct forms of renal calcification thought to provide sites for stone retention within the kidney. Here we assessed kidney stone precursor lesions in a random cohort of stone formers undergoing percutaneous nephrolithotomy. Each accessible papilla was endoscopically mapped following stone removal. The percent papillary surface area covered by plaque and plug were digitally measured using image analysis software. Stone composition was determined by micro-computed tomography and infrared analysis. A representative papillary tip was biopsied. The 24-h urine collections were used to measure supersaturation and crystal growth inhibition. The vast majority (99%) of stone formers had Randall's plaque on at least 1 papilla, while significant tubular plugging (over 1% of surface area) was present in about one-fifth of patients. Among calcium oxalate stone formers the amount of Randall's plaque correlated with higher urinary citrate levels. Tubular plugging correlated positively with pH and brushite supersaturation but negatively with citrate excretion. Lower urinary crystal growth inhibition predicted the presence of tubular plugging but not plaque. Thus, tubular plugging may be more common than previously recognized among patients with all types of stones, including some with idiopathic calcium oxalate stones.
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    Understanding, justifying, and optimizing radiation exposure for CT imaging in nephrourology
    (Springer Nature, 2019-04) Ferrero, Andrea; Takahashi, Naoki; Vrtiska, Terri J.; Krambeck, Amy E.; Lieske, John C.; McCollough, Cynthia H.; Urology, School of Medicine
    An estimated 4-5 million CT scans are performed in the USA every year to investigate nephrourological diseases such as urinary stones and renal masses. Despite the clinical benefits of CT imaging, concerns remain regarding the potential risks associated with exposure to ionizing radiation. To assess the potential risk of harmful biological effects from exposure to ionizing radiation, understanding the mechanisms by which radiation damage and repair occur is essential. Although radiation level and cancer risk follow a linear association at high doses, no strong relationship is apparent below 100 mSv, the doses used in diagnostic imaging. Furthermore, the small theoretical increase in risk of cancer incidence must be considered in the context of the clinical benefit derived from a medically indicated CT and the likelihood of cancer occurrence in the general population. Elimination of unnecessary imaging is the most important method to reduce imaging-related radiation; however, technical aspects of medically justified imaging should also be optimized, such that the required diagnostic information is retained while minimizing the dose of radiation. Despite intensive study, evidence to prove an increased cancer risk associated with radiation doses below ~100 mSv is lacking; however, concerns about ionizing radiation in medical imaging remain and can affect patient care. Overall, the principles of justification and optimization must remain the basis of clinical decision-making regarding the use of ionizing radiation in medicine.