Clinical Application Of Mean CT Value Predicting Urinary Calculi Outcome Of ESWL

OBJECTIVE To retrospectively analyze the relationship between urinary calculi CT value and treatment outcomes of extracorporeal shock wave lithotripsy(ESWL),and assess the outcomes of ESWL.METHODS Ninety patients of urinary calculi who underwent ESWL for solitary renal or upper ureteral stones in Pudong New Area Gongli Hospital of Shanghai, China from April 2014 to April 2015, were divided into 3 groups according to the CT values of the calculi. The stone free rate, sessions of ESWL and residual stone rate were recorded and compared. To collect the gravels, analyse their compositions with the German BRUKER TENSOR27 Fourier transform infrared spectrum analysis method, then record its last lithotripsy outcomes after 12 weeks according to the non-contrast computed tomography. To compare different CT values of three groups of patients with the required sessions and shock wave number for ESWL, as well as the differences between stone crushing rate and stone-free rate, etc, and record the corresponding main stone composition, then compare and analyse the relationship or differences between the CT value and stone compositions.RESULTS The lower and medium CT value groups,compared with higher group had higher stone-free rate(there was significant difference, P < 0.05), and needed less sessions of lithotripsy(statistically significant difference, P < 0.05) and smaller shock wave number(there was significant difference, P < 0.01), enjoyed better efficiency. Three groups of high, medium and low density of calculi mean CT value were respectively 1241.7±151.4, 814±152.7, 401±98.5 stone-free rate were 33.3%, 60.0% and 78.9%(P<0.01), stone crushing rate were 88.9%, 92.0% and 100%(P=0.13,>0.05), calculi residual rate were 55.6%, 32.0% and 21.1%(P=0.01,<0.05), insignificance rate were 11.1%, 8.0%, 0(P=0.13,>0.05), the required sessions of ESWL were 3.1, 2.1, 1.8(P<0.05), shock wave number were 3222±426, 1938±639?1746±327times(P<0.01). Three groups of patients with calculi ingredients in the calcium oxalate/calcium phosphate, struvite stones had statistical differences(P < 0.05), which were mainly made of calcium oxalate/calcium phosphate stones found in the composition of high density group(P < 0.01), and struvite as the main component of stones found in middle and low density group(P = 0.02, < 0.05), with cystine(P = 0.17 > 0.05) and uric acid(P = 0.09 > 0.05) as the main component of stones mainly existed in low density group, in which however both wre not the main stone composition, there was no significant differences between the low density groups..CONCLUSION The NCCT value of upper urinary stones could predict the outcomes of ESWL. Different CT value means different ESWL effect, as well as the sessions of ESWL required and different shock wave number in upper urinary stones. The actual mean Hounsfield Units of non-contrast computed tomography could predict the outcomes of the ESWL directly for urinary calculi, though great limtitations seemed to appear in preliminary evaluation of stone main components with NCCT value, and could be used as a significant referential evaluation index to ESWL therapeutic effect, which was worthy of wide clinical application.