Renal Stone Density Lab Report

Identification renal stone size and density with computed radiography and computed tomography respectively to determine its fragility by ESWL

Dr.Haider Qasim Hamood
MBChB; DMRD; FIBMS (Radio-Diagnosis)

Abstract:
Background: Renal stone is one of the most common causes of acute abdomen. There are many types of renal stones depending on stone chemical components those including calcium oxalate stone, struvite stone, uric acid stone and cystine stone. Spiral computed tomography (CT) and computed radiography (CR) are more valuable diagnostic imaging modalities in describing and evaluating the renal stone site, size and density in Hounsfield Units (HU). The aim of our study is to identify the role, sensitivity and accuracy of CT and CR in
All patients were radiologically analyzed by CT to identify renal stone density. CR is used to measure the size of stones in the same patients.

Results: According to the stone densities those determined by CT, the renal stones were divided into two groups, the first group; the stone density range from 140-319 HU and in the second group range from 319-770 HU, in the first group, the ESWL was successful and effective in stone fragmentation while it is failed in the second group. Regarding to the renal stone size which is determined by CR, the renal stones were also divided into two groups, in the first group the renal stone sizes range from 2.27-3.65 cm. and in the second group, the renal stone size range from 0.3-1.65 cm., the ESWL was more successful therapeutically in the first group, while it is failed in the second groups.

Conclusion: This study confirms the renal stone density and size help in predicting the outcome of ESWL therapy and can be considered as important parameters in the renal stone treatment by using ESWL when it is indicated.

Keywords: Renal stone fragility, CR, CT, ESWL,
DISCUSSION
ESWL today represents one of the most frequently used modalities in the treatment of upper urinary tract calculi [8,14]. The outcome of ESWL is measured in terms of stone fragmentation and clearance. Failure of ESWL may occur and this associated with non-significant exposure of the renal parenchyma to shock waves and minor complications, invariably alternative treatments are then needed, incurring additional medical expenses. Therefore, from the beginning of ESWL, factors predicting its outcome have been studied including number of stone characteristics such as fragility, size, location and composition.

Stone fragility correlates with mineral content and thus, stone density. Early work evaluated stone fragility as a predictive factor of ESWL outcome. Chaussy et al. [2] suggested that a stone was less likely to break if its density was greater than that of vertebral spine on a plain abdominal film. Mattelaer et al. [12] concluded that highly opaque stones were less fragile with ESWL therapy. Others have shown that smooth, uniform stones that appeared denser than bone (12th rib) on a plain abdominal film, responded poorly to ESWL. The limitations of these studies were the subjective nature of assessment and therefore, they have not progressed widely into clinical