Ignite Creation Date:
2024-05-05 @ 11:53 AM
Last Modification Date:
2024-10-26 @ 9:16 AM
Study NCT ID:
NCT00169780
Status:
COMPLETED
Last Update Posted:
2011-12-07
First Post:
2005-09-09
Brief Title:
Kidney Stone Structural Analysis By Helical Computed Tomography CT
Sponsor:
Indiana Kidney Stone Institute
Organization:
Indiana Kidney Stone Institute
Study Overview
Official Title:
Kidney Stone Structural Analysis by Helical Computed Tomography A Pilot Study
Status:
COMPLETED
Status Verified Date:
2011-12
Last Known Status:
None
Delayed Posting:
No
If Stopped, Why?:
Not Stopped
Has Expanded Access:
False
If Expanded Access, NCT#:
N/A
Has Expanded Access, NCT# Status:
N/A
Acronym:
None
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 SWs 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 Description:
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 patients 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 SWL fragility exists within each major stone composition group that is best explained by stone structural heterogeneity Saw et al 2000 The association of stone structure and SWL fragility is not a new concept as Dretler and Polykoff 1996 in a retrospective study of calcium oxalate stones reported four distinct patterns of stone structure on plain abdominal radiographs Unfortunately SWL fragility was not directly tested with the authors relying on clinical intuition that stones that on x-ray are smooth and more radiodense and usually higher calcium oxalate monohydrate content tend to be harder to fragment with SWL Finally the technology for clinical CT continues to advance The latest generation of multidetector helical CT machines have considerably improved image resolution over single-detector CT technology These quad-slice scanners have 4 contiguous parallel rows of x-ray detectors combined with a higher gantry rotation speed which increase the speed of data collection by a factor as high as 8 over the conventional single-slice spiral CT scanners The evolution from single-slice to multi-slice scanners does not alter image performance in terms of contrast resolution in-plane spatial resolution and radiation dose if irradiating the same volume However the benefits of quad-slice spiral CT compared to single-slice spiral CT are significant The scans may be performed with thinner CT slices which means higher spatial resolution along the longitudinal axis of the patient The scans can also be performed much faster which means improved temporal resolution and less motion artifacts Thus the ability to both predict stone composition from kidney stone CT attenuation values and delineate structural features necessary to predict stone fragility to lithotripter shock waves-if not now practical with present technology-will certainly be possible as this technology progresses
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 SWL fragility exists within each major stone composition group that is best explained by stone structural heterogeneity Saw et al 2000 The association of stone structure and SWL fragility is not a new concept as Dretler and Polykoff 1996 in a retrospective study of calcium oxalate stones reported four distinct patterns of stone structure on plain abdominal radiographs Unfortunately SWL fragility was not directly tested with the authors relying on clinical intuition that stones that on x-ray are smooth and more radiodense and usually higher calcium oxalate monohydrate content tend to be harder to fragment with SWL Finally the technology for clinical CT continues to advance The latest generation of multidetector helical CT machines have considerably improved image resolution over single-detector CT technology These quad-slice scanners have 4 contiguous parallel rows of x-ray detectors combined with a higher gantry rotation speed which increase the speed of data collection by a factor as high as 8 over the conventional single-slice spiral CT scanners The evolution from single-slice to multi-slice scanners does not alter image performance in terms of contrast resolution in-plane spatial resolution and radiation dose if irradiating the same volume However the benefits of quad-slice spiral CT compared to single-slice spiral CT are significant The scans may be performed with thinner CT slices which means higher spatial resolution along the longitudinal axis of the patient The scans can also be performed much faster which means improved temporal resolution and less motion artifacts Thus the ability to both predict stone composition from kidney stone CT attenuation values and delineate structural features necessary to predict stone fragility to lithotripter shock waves-if not now practical with present technology-will certainly be possible as this technology progresses
Study Oversight
Has Oversight DMC:
None
Is a FDA Regulated Drug?:
None
Is a FDA Regulated Device?:
None
Is an Unapproved Device?:
None
Is a PPSD?:
None
Is a US Export?:
None
Is an FDA AA801 Violation?:
None