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Use of computed tomography scout film and Hounsfield unit of computed tomography scan in predicting the radio-opacity of urinary calculi in plain kidney, ureter and bladder radiographs.

Chua ME, Gomez OR, Sapno LD, Lim SL, Morales ML - Urol Ann (2014)

Bottom Line: Statistical significance was set at P value of 0.05 or less.The determined best cut off value of HU utilized for prediction of radiographic characteristics was 630HU at which urinary calculi were not seen at CT-scout film and were KUB X-ray radio-opaque.The set HU cut-off was established of ideal accuracy with an overall sensitivity of 82.2%, specificity of 96.9% and a positive predictive value of 96.5% and negative predictive value of 83.5%.

View Article: PubMed Central - PubMed

Affiliation: St. Luke's Medical Center, Institute of Urology, Philippines.

ABSTRACT

Objective: The objective of this study is to determine the diagnostic utility of computed tomography (CT)- scout film with an optimal non-contrast helical CT scan Hounsfield unit (HU) in predicting the appearance of urinary calculus in the plain kidneys, ureter, urinary bladder (KUB)-radiograph.

Methods: A prospective cross-sectional study was executed and data were collected from June 2007 to June 2012 at a tertiary hospital. The included subjects were diagnosed to have <10mm urolithiasis with non-contrast helical CT scan and KUB X-ray, which were carried out on the same day. Both KUB radiographs and CT-scout film were read by two qualified radiologists with inter-observer standardization prior to the study. Urolithiasis characteristics such as stone location, CT attenuation value, CT-scout film and KUB radiograph appearance were recorded independently by two observers. Univariate logistic analysis with receiver operating characteristic curve was generated to determine the best cut-off HU value of urolithiases not identified in CT-scout film, but determined radio-opaque in KUB X-ray. Subsequently, its sensitivity, specificity, predictive values and likelihood ratios were calculated. Statistical significance was set at P value of 0.05 or less.

Results: Two hundred and three valid cases were included. 73 out of 75 CT-scout film detected urolithiasis were identified on plain radiograph and determined as radio-opaque. The determined best cut off value of HU utilized for prediction of radiographic characteristics was 630HU at which urinary calculi were not seen at CT-scout film and were KUB X-ray radio-opaque. The set HU cut-off was established of ideal accuracy with an overall sensitivity of 82.2%, specificity of 96.9% and a positive predictive value of 96.5% and negative predictive value of 83.5%.

Conclusion: Urolithiases identified on the CT-scout film were also seen as radiopaque on the KUB radiograph while those stones not visible on the CT-scout film, but above the optimal HU cut-off value of 630 are also likely to be radiopaque.

No MeSH data available.


Related in: MedlinePlus

Receiver operating characteristic curve for determination of Hounsfield unit (HU) 630 set as the best HU cut-off value for determination of urolithiasis appearance unidentified in computed tomography scout and kidneys, ureter, urinary bladder X-ray determined radio-opaque
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Figure 3: Receiver operating characteristic curve for determination of Hounsfield unit (HU) 630 set as the best HU cut-off value for determination of urolithiasis appearance unidentified in computed tomography scout and kidneys, ureter, urinary bladder X-ray determined radio-opaque

Mentions: The area under the curve was 0.962 [Table 2, Figure 3]. This proves that those stones not identified in the CT Scout image, but with attenuation value above the set cut-off of 630 HU is accurate in determining patients with the stone in question and have optimal accuracy.


Use of computed tomography scout film and Hounsfield unit of computed tomography scan in predicting the radio-opacity of urinary calculi in plain kidney, ureter and bladder radiographs.

Chua ME, Gomez OR, Sapno LD, Lim SL, Morales ML - Urol Ann (2014)

Receiver operating characteristic curve for determination of Hounsfield unit (HU) 630 set as the best HU cut-off value for determination of urolithiasis appearance unidentified in computed tomography scout and kidneys, ureter, urinary bladder X-ray determined radio-opaque
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4127858&req=5

Figure 3: Receiver operating characteristic curve for determination of Hounsfield unit (HU) 630 set as the best HU cut-off value for determination of urolithiasis appearance unidentified in computed tomography scout and kidneys, ureter, urinary bladder X-ray determined radio-opaque
Mentions: The area under the curve was 0.962 [Table 2, Figure 3]. This proves that those stones not identified in the CT Scout image, but with attenuation value above the set cut-off of 630 HU is accurate in determining patients with the stone in question and have optimal accuracy.

Bottom Line: Statistical significance was set at P value of 0.05 or less.The determined best cut off value of HU utilized for prediction of radiographic characteristics was 630HU at which urinary calculi were not seen at CT-scout film and were KUB X-ray radio-opaque.The set HU cut-off was established of ideal accuracy with an overall sensitivity of 82.2%, specificity of 96.9% and a positive predictive value of 96.5% and negative predictive value of 83.5%.

View Article: PubMed Central - PubMed

Affiliation: St. Luke's Medical Center, Institute of Urology, Philippines.

ABSTRACT

Objective: The objective of this study is to determine the diagnostic utility of computed tomography (CT)- scout film with an optimal non-contrast helical CT scan Hounsfield unit (HU) in predicting the appearance of urinary calculus in the plain kidneys, ureter, urinary bladder (KUB)-radiograph.

Methods: A prospective cross-sectional study was executed and data were collected from June 2007 to June 2012 at a tertiary hospital. The included subjects were diagnosed to have <10mm urolithiasis with non-contrast helical CT scan and KUB X-ray, which were carried out on the same day. Both KUB radiographs and CT-scout film were read by two qualified radiologists with inter-observer standardization prior to the study. Urolithiasis characteristics such as stone location, CT attenuation value, CT-scout film and KUB radiograph appearance were recorded independently by two observers. Univariate logistic analysis with receiver operating characteristic curve was generated to determine the best cut-off HU value of urolithiases not identified in CT-scout film, but determined radio-opaque in KUB X-ray. Subsequently, its sensitivity, specificity, predictive values and likelihood ratios were calculated. Statistical significance was set at P value of 0.05 or less.

Results: Two hundred and three valid cases were included. 73 out of 75 CT-scout film detected urolithiasis were identified on plain radiograph and determined as radio-opaque. The determined best cut off value of HU utilized for prediction of radiographic characteristics was 630HU at which urinary calculi were not seen at CT-scout film and were KUB X-ray radio-opaque. The set HU cut-off was established of ideal accuracy with an overall sensitivity of 82.2%, specificity of 96.9% and a positive predictive value of 96.5% and negative predictive value of 83.5%.

Conclusion: Urolithiases identified on the CT-scout film were also seen as radiopaque on the KUB radiograph while those stones not visible on the CT-scout film, but above the optimal HU cut-off value of 630 are also likely to be radiopaque.

No MeSH data available.


Related in: MedlinePlus