Table 2.1Subgroup analysis for possible variables contributing to heterogeneity

SubgroupMean Sensitivity (95% CI)ComparisonMean Sensitivity (95% CI)
Chaparro et al (2009)
Phospho-soda for bowel preparation83.3% (95% CI, 79%–87%), I2=73%No Phospho-soda62% (95% CI, 58%–66%), I2=93%
With fecal tagging88% (95% CI 84%–91%), I2<50%Without fecal tagging59% (95% CI 56%–63%), I2=91%
Collimation thinner than 5mm72% (95% CI 68%–76%), I2=89%Collimation ≥5mm65% (95% CI, 68%–76%), I2=95%
Reconstruction thinner than 3mm64% (95% CI, 60%–68%), I2=90%)Reconstruction ≥3mm58% (95% CI, 49%–67%), I2=87%
2-D imaging with 3-D confirmation64% (95% CI, 60–67%), I2=90%3-D imaging83% (95% CI, 78%–87%), I2=84%
Radiation dose <100mA63% (95% CI, 60%–67%), I2=95%Radiation dose >100mA79% (95% CI, 75%–83%), I2=83%
Patients at high risk of CRC or polyps65% (95% CI, 61%–68%), I2=94%Patients at average risk82% (95% CI, 77&–87%), I2=83%
Other variablesNo differences were found in other variables analysed, including study quality
Mulhall et al (2005)
Multidetector Scanner95% (95% CI, 92%–99%), I2=40%, p>0.2Single Detector Scanner82% (95% CI, 76%–92%), I2=87.1%, p<0.001
2D imaging with 3-D confirmation81.9% (95% CI, 71%–91%), I2=87.5%, p=0.023-D imaging91% (95% CI, 83%–99%), I2=53.1%, p=0.06
Collimation widthStudies using thinner slices for collimation appeared to have better sensitivity and meta-regression appeared to suggest that for every 1mm increase in collomation width there was a decrease in sensitivity of 4.9% (95% CI 0.8%–7.1%)
Fly through technologyStudies using fly through technology reported a pooled sensitivity of 99% (95% CI, 95%–100%, I2=47.6%, p=0.17).
Other VariablesFor the other subgroups investigated (year of publication, type of scanner, thickness of reconstruction interval, use of contrast and patient characteristics) no source of possible heterogeneity was found.

From: 2, Investigation, diagnosis and staging

Cover of Colorectal Cancer
Colorectal Cancer: The Diagnosis and Management of Colorectal Cancer.
NICE Clinical Guidelines, No. 131.
National Collaborating Centre for Cancer (UK).
Copyright © 2011, National Collaborating Centre for Cancer.

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