Ureteral Calculi Detection Using Low Dose Computerized Tomography Protocols is Compromised in Overweight and Underweight Patients

Heldt, Jonathan P.; Smith, Jason C.; Anderson, Kirk; Richards, Gideon; Agarwal, Gautum; Smith, Damien; Schlaifer, Amy; Pittenger, Nicholas T.; Han, Daniel; Baldwin, Brenton D.; Schroeder, Gabriel; Baldwin, D. Duane

doi:10.1016/j.juro.2012.02.2568

Cited by 14 publications

(8 citation statements)

References 21 publications

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“…[12][13][14] These studies have also often excluded or found poor performance of nonsize-adjusted protocols in more obese patients, who are at increased risk for kidney stone and incur a higher radiation dose. 1,[15][16][17][18] Previous studies have also not followed patients receiving reduced-dose CT to determine its ability to predict outcomes and need for intervention.…”

Section: Background and Importancementioning

confidence: 99%

Accuracy of Reduced-Dose Computed Tomography for Ureteral Stones in Emergency Department Patients

Moore

Daniels

Ghita

et al. 2015

Annals of Emergency Medicine

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Study objective-Reduced-dose computed tomography (CT) scans have been recommended for diagnosis of kidney stone but are rarely used in the emergency department (ED) setting. Test characteristics are incompletely characterized, particularly in obese patients. Our primary outcome is to determine the sensitivity and specificity of a reduced-dose CT protocol for symptomatic ureteral stones, particularly those large enough to require intervention, using a protocol stratified by patient size.Methods-This was a prospective, blinded observational study of 201 patients at an academic medical center. Consenting subjects underwent both regular-and reduced-dose CT, stratified into a high and low body mass index (BMI) protocol based on effective abdominal diameter. Reduceddose CT scans were interpreted by radiologists blinded to regular-dose interpretations. Follow-up for outcome and intervention was performed at 90 days.Results-CT scans with both regular and reduced doses were conducted for 201 patients, with 63% receiving the high BMI reduced-dose protocol. Ureteral stone was identified in 102 patients (50.7%) of those receiving regular-dose CT, with a ureteral stone greater than 5 mm identified in 26 subjects (12.9%). Sensitivity of the reduced-dose CT for any ureteral stone was 90.2% (95% confidence interval [CI] 82.3% to 95.0%), with a specificity of 99.0% (95% CI 93.7% to 100.0%). For stones greater than 5 mm, sensitivity was 100% (95% CI 85.0% to 100.0%). Reduced-dose CT identified 96% of patients who required intervention for ureteral stone within 90 days. Mean * Corresponding Author. Chris.Moore@yale.edu, Twitter: Chris.Moore@Yale_EUS. Author contributions: CLM, MG, and GPG conceived the study and designed the trial. CLM, DS, and CPG obtained research funding.CLM and SL supervised the conduct of the trial and data collection. SL participated in recruitment of patients. GG performed overreadings of the CT scans in the trial. CLM, SL, and AM managed the data, including quality control. AM and CPG provided statistical advice. BD, GG, AM, DS, and CPG provided advisement on study design and methodology. CLM, SL, AM, and CPG analyzed the data. CLM drafted the article, and all authors contributed substantially to its revision. CLM takes responsibility for the paper as a whole.Presented as an abstract at the Society for Academic Emergency Medicine annual meeting, May 2013, Atlanta, GA.The content of this article is solely the responsibility of the authors and does not necessarily represent the official views of the AHRQ. HHS Public Access Author Manuscript Author ManuscriptAuthor ManuscriptAuthor Manuscript reduction in size-specific dose estimate was 18.6 milligray (mGy), from 21.7 mGy (SD 9.7) to 3.4 mGy (SD 0.9). Conclusion-CT

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Section: Background and Importancementioning

confidence: 99%

Accuracy of Reduced-Dose Computed Tomography for Ureteral Stones in Emergency Department Patients

Moore

Daniels

Ghita

et al. 2015

Annals of Emergency Medicine

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“…Interestingly, a more recent cadaveric simulation study carried out by Heldt et al . [29] using 3 cadavers of increasing weight/BMI found that although increasing adiposity negatively affected the diagnostic accuracy of ultra-low dose CT (<1 mSv) in detecting ureteral calculi, the sensitivity and specificity of ultra-low dose CT for detecting ureteral calculi was also decreased in underweight cadavers; presumably due to a lack of perinephric and peri-ureteral fat to help delineate the ureters from surrounding structures. However, there was no significant difference in sensitivity and/or specificity at radiation doses of 2 mSv or more, which would still constitute a “low-dose” scan using our definition.…”

Section: Discussionmentioning

confidence: 99%

Should low-dose computed tomography kidneys, ureter and bladder be the new investigation of choice in suspected renal colic?: A systematic review

Drake¹,

Jain²,

Bryant³

et al. 2014

Indian J Urol

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Introduction:Computed tomography kidneys, ureter and bladder (CTKUB) is the accepted gold standard investigation for suspected renal colic. Dose considerations are particularly pertinent in the context of detecting urolithiasis given the high risk of disease recurrence, which can necessitate multiple radiological examinations over the lifetime of a stone-former. We performed a systematic review of the literature to see whether there was any evidence that reducing the effective radiation dose of a CTKUB compromised the diagnostic accuracy of the scan.Materials and Methods:Relevant databases including MedLine, EMBASE, DARE and the Cochrane Library were searched from inception to October 2012. All English language articles reporting on prospective studies where non-contrast, low-dose CT (LDCT) was used to investigate adults (males and non-pregnant females) presenting with flank pain or suspected urolithiasis were included. LDCT was defined as an effective radiation dose <3 mSv per examination.Results:Our initial search identified 497 records. After removing duplicates, 390 abstracts were screened, of which 375 were excluded, principally because outcomes of interest were not presented. Six papers remained for the final analysis, reporting on a total of 903 patients. Individual studies showed a prevalence of urolithiasis ranging between 36% and 88%, with additional pathologies found in 5-16%. The effective radiation dose of the LDCT techniques used ranged from 0.5 to 2.8 mSv. The sensitivity of LDCT for diagnosing stone disease was 90-97% with a specificity of 86-100%.Conclusions:The sensitivity and specificity of CTKUB for diagnosing urolithiasis remains high, even when the effective radiation dose is lowered. LDCT may miss some small stones (<3 mm), especially in obese patients (>30 kg/m2), but in this group LDCT still identifies most alternative diagnoses. With at least one level 1A and two level 1B studies supporting the use of LDCT, there is Grade A recommendation for its use as the first-line investigation in suspected renal colic in non-obese patients.

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“…In recent years, the use of low-dose CT imaging (2-3.5 mSv) has been thoroughly investigated [17,[31][32][33][34][35]. These studies have consistently shown that low-dose CT provides a sensitivity and specificity >95 % and is similar to conventional CT for the detection of both renal and ureteral calculi [31,36,37].…”

Section: Reducing Radiation During Work-up For Urolithiasismentioning

confidence: 99%

“…Similarly, very thin and very obese patients are better imaged with low-dose, not ultra lowdose imaging, as image noise can impair image clarity [32]. Finally, patients with spinal hardware, reservoirs, hip replacements, or other implants may produce image noise that compromises the radiologic detection of calculi in the corresponding areas with both low and ultra low-dose CT techniques.…”

Section: Reducing Radiation During Work-up For Urolithiasismentioning

confidence: 99%

Techniques for Minimizing Radiation Exposure During Evaluation, Surgical Treatment, and Follow-up of Urinary Lithiasis

Arenas

Baldwin

2015

Curr Urol Rep

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Patients receive significant radiation exposure during the diagnosis, treatment, and follow-up of urinary stone disease. This radiation exposure may result in patient harm and is believed to contribute to the risk for malignancy. This review will present current information to allow surgeons to optimize their diagnostic, treatment, and follow-up regimens to allow optimal care of stone disease patients at the lowest radiation dose possible.

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Ureteral Calculi Detection Using Low Dose Computerized Tomography Protocols is Compromised in Overweight and Underweight Patients

Cited by 14 publications

References 21 publications

Accuracy of Reduced-Dose Computed Tomography for Ureteral Stones in Emergency Department Patients

Accuracy of Reduced-Dose Computed Tomography for Ureteral Stones in Emergency Department Patients

Should low-dose computed tomography kidneys, ureter and bladder be the new investigation of choice in suspected renal colic?: A systematic review

Techniques for Minimizing Radiation Exposure During Evaluation, Surgical Treatment, and Follow-up of Urinary Lithiasis

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