In-Vivo relation between CT attenuation value and shockwave fragmentation.
OBJECTIVE
To use CT attenuation numbers as a means of determining the susceptibility of an artificial stone to in-vivo fragmentation with extracorporeal shockwave lithotripsy (SWL).


METHODS
Four types of artificial kidney stones having different CT attenuation values were used. One randomly selected stone was implanted in the renal pelvis of a kidney of 12 young pigs and exposed in vivo to 2500 shockwaves (21 kV) using an electrohydraulic lithotripter. Bilateral nephrectomy was performed after SWL. Fragments were strained through a mesh with a 3.1-mm grid, and the debris left on the mesh was dried and weighed. Fragmentation coefficients (FCs) were associated with CT attenuation values using a statistical model.


RESULTS
The relation between FC and CT number was significant, indicating that as CT attenuation increases, FC is reduced. Larger stone fragments were obtained from stones with higher CT numbers. Initial stone weight was not a significant explanation for variations in FC.


CONCLUSIONS
The CT values could be helpful in selecting patients for SWL in the future. However, other parameters such as stone porosity, shape, and roughness also will have to be considered.
Hurtado
Fernando
F
Nuevo Hospital Civil, Universidad de Guadalajara, Guadalajara, Jalisco, C.T. 44340 México.
Gutiérrez
Jorge
J
Castaño-Tostado
Eduardo
E
Bustos
Julio
J
Mues
Enrique
E
Del Sol Quintero
María
M
Méndez
Arturo
A
Loske
Achim M
AM
D000818:Animals; D004195:Disease Models, Animal; D007669:Kidney Calculi / Q000000981:diagnostic imaging* / Q000628:therapy*; D008096:Lithotripsy; D008297:Male; D008954:Models, Biological; D015233:Models, Statistical; D009392:Nephrectomy; D013552:Swine; D014057:Tomography, X-Ray Computed