PURPOSE: To differentiate calcium oxalate monohydrate (COM) and calcium oxalate dihydrate (COD) kidney stones using micro-CT and clinical CT images.
MATERIALS AND METHODS: A total of 37 human kidney stones (22 COM and 15 COD) were scanned using a commercial micro CT scanner with pixel sizes of 7-23 microns. Under an IRB-approved protocol, image data of 19 stones > 5mm in size (10 COM and 9 COD) were retrieved from a cohort of 80 patients who underwent clinical dual-energy CT (DECT) exams for clinical indications and had stones available for infrared spectroscopic compositional analysis. Both micro-CT and clinical CT images were processed using an in-house software, which quantified stone surface morphology with curvature based calculations. A shape index was generated as a quantitative shape metric to differentiate COM vs. COD stones. Statistical tests were performed to test the performance of the shape index.
RESULTS: On micro-CT images, the shape index was significantly different between COM and COD stones (p< 0.0001). The area under the curve (AUC) of the receiver operating characteristic curve was 0.92. With an optimal cutoff, the sensitivity and specificity were 0.93 and 0.91, respectively. On clinical DECT images, a significant morphological difference was also detected (p=0.007). The AUC, sensitivity and specificity were 0.90, 1 and 0.73, respectively.
CONCLUSIONS: A morphological difference was detectable in micro-CT images and in clinical images between COM and COD stones larger than 5 mm. The shape index is a highly promising method, which can separate COM and COD stones with reasonable accuracy.
Written by:
Duan X, Qu M, Wang J, Trevathan J, Vrtiska T, Williams JC Jr, Krambeck A, Lieske J, McCollough C. Are you the author?
Department of Radiology, Mayo Clinic, 200 First ST SW, Rochester MN, 55905.
Reference: J Urol. 2012 Nov 7. pii: S0022-5347(12)05469-9.
doi: :10.1016/j.juro.2012.11.004
PubMed Abstract
PMID: 23142201
Go "Beyond the Abstract" - Read an article written by the authors for UroToday.com
UroToday.com Stone Disease Section
