Accurate Determination of Chemical Composition of Urinary Calculi by Spiral Computerized Tomography

MOSTAFAVI, MOHAMMAD R.; ERNST, RANDY D.; Saltzman, Brian

doi:10.1097/00005392-199803000-00010

Cited by 61 publications

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“…Several in vitro and in vivo studies have shown that this approach can discriminate UA from non-UA stones (7)(8)(9)(10)(11). Combining the analysis of CT numbers with visual assessment of stone morphology using a wide window setting (eg, bone window) substantially improves the accuracy of stone characterization (12).…”

Section: Introductionmentioning

confidence: 99%

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Noninvasive Differentiation of Uric Acid versus Non–Uric Acid Kidney Stones Using Dual-Energy CT

et al. 2007

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Rationale and Objectives-To determine the accuracy and sensitivity for dual-energy computed tomography (DECT) discrimination of uric acid (UA) stones from other (non-UA) renal stones in a commercially implemented product.Materials and Methods-Forty human renal stones comprising uric acid (n = 16), hydroxyapatite (n = 8), calcium ox-alate (n = 8), and cystine (n = 8) were inserted in four porcine kidneys (10 each) and placed inside a 32-cm water tank anterior to a cadaver spine. Spiral dual-energy scans were obtained on a dual-source, 64-slice computed tomography (CT) system using a clinical protocol and automatic exposure control. Scanning was performed at two different collimations (0.6 mm and 1.2 mm) and within three phantom sizes (medium, large, and extra large) resulting in a total of six image datasets. These datasets were analyzed using the dual-energy software tool available on the CT system for both accuracy (number of stones correctly classified as either UA or non-UA) and sensitivity (for UA stones). Stone characterization was correlated with micro-CT.Results-For the medium and large phantom sizes, the DECT technique demonstrated 100% accuracy (40/40), regardless of collimation. For the extra large phantom size and the 0.6-mm collimation (resulting in the noisiest dataset), three (two cystine and one small UA) stones could not be classified (93% accuracy and 94% sensitivity). For the extra large phantom size and the 1.2-mm collimation, the dual-energy tool failed to identify two small UA stones (95% accuracy and 88% sensitivity). Conclusions-In an anthropomorphic phantom model, dual-energy CT can accurately discriminate uric acid stones from other stone types. KeywordsKidney stones; renal calculi; dual-energy computed tomography; uric acid; urolithiasis Symptomatic urinary stone disease affects approximately 900,000 persons in the United States each year, resulting in annual medical cost of $5.3 billion. Nephrolithiasis has traditionally been evaluated using plain film radiographic techniques with or without tomography or administration of intravenous contrast for excretory urography. Over recent years, however, computed tomography (CT) has supplanted these traditional techniques because of increased sensitivity, speed, and the lack of intravenous contrast (1 Although state-of-the-art CT provides accurate submillimeter details of the size and location of renal stones (4,5), current routine clinical image analysis does not differentiate stone composition. This is particularly important in the case of uric acid (UA) stones (~10% of cases), because urinary alkalinization can be prescribed to dissolve UA stones and could thereby be initiated at presentation rather than following lengthy metabolic workup. Therefore simple and reliable differentiation of UA versus non-UA stone composition could potentially allow patients with UA stones to avoid invasive interventional urinary procedures for stone removal or external shock wave lithotripsy, both of which are expensive and might result in renal hemorrh...

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Section: Introductionmentioning

confidence: 99%

“…As a consequence, UA stones have higher CT numbers at higher kVp than at lower kVp, whereas non-UA stones have higher CT numbers at lower kVp than at higher kVp. Indeed, some previous studies (8,13,15) have already exploited this fact and used the difference between CT numbers at high and low kVp to improve the prediction accuracy of the CT number approach.…”

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confidence: 99%

Noninvasive Differentiation of Uric Acid versus Non–Uric Acid Kidney Stones Using Dual-Energy CT

et al. 2007

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“…Study by Mostafavi et al attempted to determine the chemical composition of urinary calculi by CT scanning in an in vitro setting. 13,14 It was done using the absolute CT value measured at 120 kV and the dual kilovolt CT values measured at 80 and 120 kV. They found that absolute CT value measured at 120 kV was able to identify precisely the chemical composition of uric acid, struvite and calcium oxalate stones whereas it was imprecise in differentiating calcium oxalate from brushite stone and struvite from cystine stone.…”

Section: Discussionmentioning

confidence: 99%

Non-contrast spiral computed tomography diagnosis of urolithiasis and associated features: hospital based study

2016

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“…Even though most stones are visible on CT, the struvite stones and uric acid stones are radiolucent on radiography [22]. Due to the difference in composition of renal stones, there is a wide variation in the attenuation on multidetector CT. For example, calcium monohydrate and brushite measure 1700-2800 HU, calcium phosphate 1200-1600 HU, cystine 600-1100 HU, struvite 600-900 HU, and uric acid 200-450 HU [23][24][25].…”

Section: Stone Compositionmentioning

confidence: 99%

Urinary Obstruction, Stone Disease, and Infection

Nicola

Menias

2018

IDKD Springer Series

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Accurate Determination of Chemical Composition of Urinary Calculi by Spiral Computerized Tomography

Abstract: This study demonstrates that the chemical composition of urinary calculi can be accurately determined by CT scanning in an in vitro setting.

Cited by 61 publications

References 0 publications

Noninvasive Differentiation of Uric Acid versus Non–Uric Acid Kidney Stones Using Dual-Energy CT

Noninvasive Differentiation of Uric Acid versus Non–Uric Acid Kidney Stones Using Dual-Energy CT

Non-contrast spiral computed tomography diagnosis of urolithiasis and associated features: hospital based study

Urinary Obstruction, Stone Disease, and Infection

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