Key result
The DICOM-based software significantly reduced analysis time but yielded slightly larger CIMT measurements (mean difference 0.02 mm) compared to older bitmap-based software, and increasing the number of measurements did not improve reproducibility.
Why the study?
Does a new DICOM-based software measuring CIMT on multiple frames improve reproducibility and analysis time compared to older bitmap-based software?
Does a new DICOM-based software measuring CIMT on multiple frames improve reproducibility and analysis time compared to older bitmap-based software?
Mean Difference: 0.02 (95% CI 0.01–0.03)
While DICOM-based software significantly reduced CIMT analysis time, a ten-fold increase in the number of measurements used to calculate CIMT did not improve reproducibility.
May shorten CIMT analysis time; leaves open whether DICOM software improves reproducibility versus bitmap methods.
BACKGROUND: Carotid intima-media thickness (CIMT) measured by B-mode ultrasonography is a marker of atherosclerosis and is commonly used as an outcome in intervention trials. We have developed DICOM-based software that measures CIMT rapidly on multiple end-diastolic image frames. The aims of this study were to compare the performance of our new software with older bitmap-based CIMT measurement software and to determine whether a ten-fold increase in the number of measurements used to calculate mean CIMT would improve reproducibility. METHODS: Two independent sonographers recorded replicate carotid scans in thirty volunteers and two blinded observers measured CIMT off-line using the new DICOM-based software and older bitmap-based software. A Bland-Altman plot was used to compare CIMT results from the two software programs and t-tests were used to compare analysis times. F-tests were used to compare the co-efficients of variation (CVs) from a standard six-frame measurement protocol with CVs from a sixty-frame measurement protocol. Ordinary least products (OLP) regression was used to test for sonographer and observer biases. RESULTS: The new DICOM-based software was much faster than older bitmap-based software (average measurement time for one scan 3.4 +/- 0.6 minutes versus 8.4 +/- 1.8 minutes, p < 0.0001) but CIMT measurements were larger than those made using the alternative software (+0.02 mm, 95%CI 0.01-0.03 mm). The sixty-frame measurement protocol had worse reproducibility than the six-frame protocol (inter-observer CV 5.1% vs 3.5%, p = 0.004) and inter and intra-observer biases were more pronounced in the sixty-frame than the six-frame results. CONCLUSION: While the use of DICOM-based software significantly reduced analysis time, a ten-fold increase in the number of measurements used to calculate CIMT did not improve reproducibility. In addition, we found that observer biases caused differences in mean CIMT of a magnitude commonly reported as significant in intervention trials. Our results highlight the importance of good study design with concurrent controls and the need to ensure that no observer drift occurs between baseline and follow-up measurements when CIMT is used to monitor the effect of an intervention.
No takes yet. Share an insight, caveat, or question.
Potter et al. (2007) studied Atherosclerosis (Carotid intima-medial thickness) (n=30). DICOM-based CIMT measurement software vs. Bitmap-based CIMT measurement software was evaluated on Difference in measured Carotid intima-medial thickness (CIMT) (MD 0.02 mm, 95% CI 0.01-0.03). The DICOM-based software significantly reduced analysis time but yielded slightly larger CIMT measurements (mean difference 0.02 mm) compared to older bitmap-based software, and increasing the number of measurements did not improve reproducibility.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: