TY - JOUR
T1 - Stone characteristics on noncontrast computed tomography
T2 - Establishing definitive patterns to discriminate calcium and uric acid compositions
AU - Marchini, Giovanni S.
AU - Remer, Erick M.
AU - Gebreselassie, Surafel
AU - Liu, Xiaobo
AU - Pynadath, Cindy
AU - Snyder, Grace
AU - Monga, Manoj
PY - 2013/9
Y1 - 2013/9
N2 - Objective To evaluate if different stone compositions can be distinguished by variations in Hounsfield unit (HU) patterns from stone core to periphery. Materials and Methods We retrospectively reviewed our stone registry searching for pure uric acid (UA) and calcium oxalate (CaOx) stones. Inclusion criteria comprised: pure calculi; noncontrast computed tomography before stone analysis; and stone size ≥4 mm. A single urologist reviewed all images (abdominal/bone windows). Absolute HU attenuation was measured in the center (core) and edges (periphery) of each stone. HU density (HU/size) and stone volume were calculated. Categorical variables were compared with Chi-square/Fisher exact test; continuous with analysis of variance/Student t test. Spearman's test was used correlate HU values and stone dimensions. A P <.05 was considered significant. Results Included were 47 UA and 36 CaOx stones. CaOx cohort had higher HU values for all parameters (P <.001). HU variation (core-periphery) was more homogeneous in the UA group (-25%) than in the CaOx group (-52%). Stone dimensions had a significant positive correlation with HU values in CaOx cohort. In the UA group, stone volume and periphery HU had significant positive correlation. On bone window, CaOx stones had a heterogeneous pattern with a higher attenuation core with decreasing attenuation toward the periphery; UA calculi had a more homogeneous constant frosted white cloudy appearance. Conclusion Stone size does not affect HU for UA stone, but has a positive correlation with CaOx stone. UA stones can be differentiated from CaOx by evaluating variation in HU from core to periphery and by subjective evaluation of homogeneity in bone windows.
AB - Objective To evaluate if different stone compositions can be distinguished by variations in Hounsfield unit (HU) patterns from stone core to periphery. Materials and Methods We retrospectively reviewed our stone registry searching for pure uric acid (UA) and calcium oxalate (CaOx) stones. Inclusion criteria comprised: pure calculi; noncontrast computed tomography before stone analysis; and stone size ≥4 mm. A single urologist reviewed all images (abdominal/bone windows). Absolute HU attenuation was measured in the center (core) and edges (periphery) of each stone. HU density (HU/size) and stone volume were calculated. Categorical variables were compared with Chi-square/Fisher exact test; continuous with analysis of variance/Student t test. Spearman's test was used correlate HU values and stone dimensions. A P <.05 was considered significant. Results Included were 47 UA and 36 CaOx stones. CaOx cohort had higher HU values for all parameters (P <.001). HU variation (core-periphery) was more homogeneous in the UA group (-25%) than in the CaOx group (-52%). Stone dimensions had a significant positive correlation with HU values in CaOx cohort. In the UA group, stone volume and periphery HU had significant positive correlation. On bone window, CaOx stones had a heterogeneous pattern with a higher attenuation core with decreasing attenuation toward the periphery; UA calculi had a more homogeneous constant frosted white cloudy appearance. Conclusion Stone size does not affect HU for UA stone, but has a positive correlation with CaOx stone. UA stones can be differentiated from CaOx by evaluating variation in HU from core to periphery and by subjective evaluation of homogeneity in bone windows.
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U2 - 10.1016/j.urology.2013.03.092
DO - 10.1016/j.urology.2013.03.092
M3 - Article
AN - SCOPUS:84883224771
SN - 0090-4295
VL - 82
SP - 539
EP - 546
JO - Urology
JF - Urology
IS - 3
ER -