Clinical Trial: Kidney Stone Structural Analysis By Helical Computed Tomography (CT)
Study Status: Completed
Recruit Status: Completed
Study Type: Observational
Official Title: Kidney Stone Structural Analysis by Helical Computed Tomography (A Pilot Study)
Brief Summary: Current practices of the diagnosis of urinary stones gives little information on the probable fragility of stones using shock wave lithotripsy (SWL), and many patients receive more SW's than is necessary to break up their stones. Indeed, some patients are treated with SWL when their stones cannot be fragmented using this technology. The investigators have ample evidence that computed tomography (CT) images of kidney stones can reveal significant internal structure in stones—structure that is likely to be useful in predicting stone fragility—but no one has explored the use of clinical helical CT for this purpose. Also, the investigators do not know the effect that the human body wall and kidney tissue will have on the resolution of kidney stone structure with helical CT.
Detailed Summary:
Helical computed tomography has become the radiologic tool of choice in the assessment and treatment of patients with urinary tract calculi (Hubert et al, 1997; Smith et al, 1999). However, the full potential of helical CT to differentiate among stone types by structure or radiodensity has yet to be realized. Most CT scans for stones are used simply to identify the existence of a stone and give some indication of its size and location. These scans are viewed using soft tissue windows, in order to look for other possible causes of the patient's pain, such as appendicitis, gallstones, and colonic diverticulitis. However, soft tissue windows do not show structure within the kidney stone: stones appear as bright white objects in these images. The potential for observing structure in stones (using viewing windows closer to those used to view bone) has not been assessed in clinical studies. Currently, only the average CT attenuation value of urinary tract calculi has been investigated as an indicator of stone composition (Nakada et al, 2000; Mostafavi et al, 1998; Kuwahara et al, 1984). The average CT attenuation value has been shown to be useful for distinguishing some stones (such as uric acid from calcium oxalate) but considerable overlap in CT attenuation between stone types exist.
Treatment of urinary tract calculi is influenced by many factors including stone location, size and composition. Shock wave lithotripsy (SWL) is an effective, non-invasive method that is utilized to treat the majority of renal calculi. However, while some kidney stones are easily fragmented by SWL, other stones of similar composition are SW-resistant and must be removed by an invasive method following the failed lithotripsy. In addition, SWL is not without complications with long-term risks of hypertension and renal insufficiency (Evan et al, 1998; Willis et al, 1998). Considerable variation in S
Sponsor: Indiana Kidney Stone Institute
Current Primary Outcome: To determine whether available clinical helical CT is able to reveal internal structure of kidney stones [ Time Frame: Post op day one ]
Original Primary Outcome: To determine whether available clinical helical CT is able to reveal internal structure of kidney stones.
Current Secondary Outcome: To determine if high resolution CT can differentiate between plaque and renal calculi. [ Time Frame: Post op day one ]
Original Secondary Outcome:
Information By: Indiana Kidney Stone Institute
Dates:
Date Received: September 9, 2005
Date Started: July 2002
Date Completion:
Last Updated: December 5, 2011
Last Verified: December 2011
