Xiaohu Li, Presenter: Nothing to Disclose

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

Shuai Zhang, Abstract Co-Author: Nothing to Disclose

Ken Chen, Abstract Co-Author: Employee, General Electric Company

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

Yifei Zhang, Abstract Co-Author: Nothing to Disclose

Wanqin Wang, Abstract Co-Author: Nothing to Disclose

Xingwang Wu, Abstract Co-Author: Nothing to Disclose

The purpose of this study was to select optimal monochromatic level for differentiating the composition of kidney stone

Eighteen freshly excised pig kidneys with 108 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 spectral CT(Discovery CT750 HD) scans with gemstone spectral imaging (GSI) to obtain two sets of images: polychromatic images(140kVp) and monochromatic images(70keV) during a single GSI acquisition. All GSI data were transferred to ADW4.4 workstation to acquire 21 sets of monochromatic images (40-140keV, interval of 5keV) with GSI Viewer. CT numbers of stones were measured and compared at 22 sets of images(polychromatic images and 21 sets of monochromatic images) in terms of the stone composition determined by infrared spectrometer after CT examination.

According to the result of infrared spectroscopy, 108 stones were divided into five groups: uric acid stones(UA,n=13), struvite stones(STR,n=24),cystine stones(CYS,n=14), calcium phosphate(CaP,n=18),calcium oxalate (COX, n=39). 1. At polychromatic images, The mean CT numbers of each group were 461.85±103.73HU、764.96±221.72HU、564.89±129.09HU、1601.89±200.14HU、1483.19±286.24HU. There were not significant differences in CT numbers of both between Cap and COX and between UA and CYS(P=0.068 and P=0.240,respectively). 2. At two sets of monochromatic images(45 and 50keV), The mean CT numbers of each group were 548.35±231.33HU、1256.85±353.49HU、868.82±204.47HU、2839.02±125.96HU、2629.52±332.13HU,503.08±167.59HU、1055.98±290.09HU、739.75±172.22HU、2567.44±177.62HU、2267.47±384.92HU. There were significant differences in CT numbers between two random groups(P<0.05). 3. At other sets of monochromatic images, the difference in CT numbers between at least two random groups was no statistically significant(P<0.05).  

In GSI of kidney stone, the optimal monochromatic levels were determined at 45 and 50keV to better differentiate the composition of kidney stone compared to polychromatic images(140kVp)

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, Zhang, S, Chen, K, Yu, Y, Zhang, Y, Wang, W, Wu, X, Gemstone Spectral Imaging of Kidney Stone in Vitro: Initial Results of Selecting Optimal Monochromatic Level for Determination of Kidney Stone Composition.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11007809.html