Xiaohu Li, Presenter: Nothing to Disclose

Bin Liu MD, Abstract Co-Author: Nothing to Disclose

Yongqiang Yu MD, Abstract Co-Author: Nothing to Disclose

To evaluate the feasibility of determining the majority chemical composition of calcium kidney Stone using gemstone spectral imaging(GSI) of spectral CT  

Twelve freshly excised pig kidneys with 72 extracted human kidney stones in them (two in the upper calices, tow in the renal pelvis and two in the lower calices of each kidney) which were immersed in a 10cm-deep water tank underwent CT(Discovery CT750 HD) scans with GSI mode and conventional polychromatic imaging (CPI,120kVp) mode, respectively. All GSI data were transferred to Workstation (AW4.4, GE Healthcare) to obtain the Effective Atomic Number(Zeff) ,Calcium Water Ratio(CWR),CT numbers at 50keV image and 120kVp image,which were compared among the stone groups. The composition of calcium stones was determined by infrared spectrometer  

According to the result of stone composition determined by infrared spectroscopy, 72 stones were divided into five groups: Calcium oxalate monohydrate(COM,n=38),Calcium oxalate dihydrate(COD,n=6),Brushite(BRU,n=6),Calcium Carbonate(CCA,n=5),Dahllite(DAH,n=17).The mean Zeff , CWR and the mean CT numbers at 50keV images and 120kVp images of each group were as below: COM(15.27±0.70,0.6020±0.0925,2267.47±384.92HU,1483±186.24), COD(15.42±0.24,0.5441±0.0474,2119.50±83.15,1384.88±126.02), BRU(15.66±0.23,0.6230±0.0561,2747.48±131.89,1860.42±47.65), CCA(16.08±0.17,0.7256±0.0279,2516.32±104.66,1643.08±115.97), DAH(16.19±0.49,0.7100±0.1064,3484.78±221.58,1536.84±187.11). There were significant differences in the mean Zeff ,CRW,CT numbers at both 50keV and 120kVp among groups(F=8.391,7.266,5.084,4.148,P=0.000,0.000,0.001,0.005). Comparison further between two groups showed there were significant differences in both the mean Zeff and CRW between COM and CCA (P<0.05), in the mean Zeff 、CRW and CT numbers at 50keV images both between COM and DAH and between COD and DAH (P<0.05) as well as in both CRW and CT numbers at 50keV images between COD and CCA (P<0.05). While there were no significant differences in CT numbers at 120kVp images between two random groups.

Compared with conventional polychromatic imaging, GSI can provide particular information to differentiate parts of calcium kidney stone by the mean Zeff, CRW and CT numbers at 50keV images.  

Determination of stone composition by GSI can help urologist choose the optimal treatment project to avoid complications and unnecessary surgical intervention  

Li, X, Liu, B, Yu, Y, Can Gemstone Spectral Imaging Differentiate the Composition of Calcium Kidney Stone? An Experimental Study Compared with Conventional Polychromatic Imaging (120kVp).  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12020312.html