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Comparison of transaxial source images and 3-plane, thin-slab maximal intensity projection images for the diagnosis of coronary artery stenosis with using ECG-gated cardiac CT.

Choi JW, Seo JB, Do KH, Choi SI, Lee W, Ko SM, Lee SH, Lee JS, Song JW, Song KS, Lim TH - Korean J Radiol (2006 Jan-Mar)

Bottom Line: There was no statistical difference in the area under the ROC curve between transaxial images and MIP images for the detection of HSS (0.8375 and 0.8708, respectively; p > 0.05).The mean reading time for the transaxial source images and the MIP images was 116 and 126.5 minutes, respectively.The diagnostic performance of the MIP images for detecting HSS of the coronary arteries is acceptable and this technique's ability to detect HSS is comparable to that of the transaxial source images.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea.

ABSTRACT

Objective: We wanted to compare the transaxial source images with the optimized three plane, thin-slab maximum intensity projection (MIP) images from electrocardiographic (ECG)-gated cardiac CT for their ability to detect hemodynamically significant stenosis (HSS), and we did this by means of performing a receiver operating characteristic (ROC) analysis.

Materials and methods: Twenty-eight patients with a heart rate less than 66 beats per minute and who were undergoing both retrospective ECG-gated cardiac CT and conventional coronary angiography were included in this study. The contrast-enhanced CT scans were obtained with a collimation of 16 x 0.75-mm and a rotation time of 420 msec. The transaxial images were reconstructed at the mid-diastolic phase with a 1-mm slice thickness and a 0.5-mm increment. Using the transaxial images, the slab MIP images were created with a 4-mm thickness and a 2-mm increment, and they covered the entire heart in the horizontal long axis (4 chamber view), in the vertical long axis (2 chamber view) and in the short axis. The transaxial images and MIP images were independently evaluated for their ability to detect HSS. Conventional coronary angiograms of the same study group served as the standard of reference. Four radiologists were requested to rank each image with using a five-point scale (1 = definitely negative, 2 = probably negative, 3 = indeterminate, 4 = probably positive, and 5 = definitely positive) for the presence of HSS; the data were then interpreted using ROC analysis.

Results: There was no statistical difference in the area under the ROC curve between transaxial images and MIP images for the detection of HSS (0.8375 and 0.8708, respectively; p > 0.05). The mean reading time for the transaxial source images and the MIP images was 116 and 126.5 minutes, respectively.

Conclusion: The diagnostic performance of the MIP images for detecting HSS of the coronary arteries is acceptable and this technique's ability to detect HSS is comparable to that of the transaxial source images.

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Related in: MedlinePlus

Receiver operating characteristic curves for the transaxial images and the MIP images from each reader. The Az values of the MIP images were larger than those of the transaxial images except for reader 3. However, the difference was statistically significant only for reader 2. Axial = Transaxial image, TPF = true positive fraction, FPF = false positive fraction.
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Figure 3: Receiver operating characteristic curves for the transaxial images and the MIP images from each reader. The Az values of the MIP images were larger than those of the transaxial images except for reader 3. However, the difference was statistically significant only for reader 2. Axial = Transaxial image, TPF = true positive fraction, FPF = false positive fraction.

Mentions: The mean Az values, which indicate the performance of each reader, are given in Table 2. The 95% CIs for the mean differences in the Az values between the two image sets and the reading time of each session are also provided. We found that for all three radiologists, the Az values from the MIP images were higher than those Az values from the transaxial images (Fig. 3), however, the difference was significant for only one reader. Overall, the Az values from both image sets were not significantly different. When Grade 3 (indeterminate) or higher were regarded as positive, the sensitivities, specificities, and accuracies were 65%, 86%, and 80% for the transaxial images and 71%, 84%, and 80% for the MIP images, respectively. When Grade 4 (probably positive) was used as the cut-off point, the sensitivities, specificities and accuracies were 47%, 92%, and 80% for the transaxial images and 54%, 92%, and 81% for the MIP images. The mean reading times for the transaxial images and the MIP images were 116 and 126.5 minutes, respectively; these findings were not statistically significant (Wilcoxon-Signed Ranks test, p value = 0.465). The mean numbers of the transaxial and MIP images per patient were 238 and 162, respectively.


Comparison of transaxial source images and 3-plane, thin-slab maximal intensity projection images for the diagnosis of coronary artery stenosis with using ECG-gated cardiac CT.

Choi JW, Seo JB, Do KH, Choi SI, Lee W, Ko SM, Lee SH, Lee JS, Song JW, Song KS, Lim TH - Korean J Radiol (2006 Jan-Mar)

Receiver operating characteristic curves for the transaxial images and the MIP images from each reader. The Az values of the MIP images were larger than those of the transaxial images except for reader 3. However, the difference was statistically significant only for reader 2. Axial = Transaxial image, TPF = true positive fraction, FPF = false positive fraction.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2667573&req=5

Figure 3: Receiver operating characteristic curves for the transaxial images and the MIP images from each reader. The Az values of the MIP images were larger than those of the transaxial images except for reader 3. However, the difference was statistically significant only for reader 2. Axial = Transaxial image, TPF = true positive fraction, FPF = false positive fraction.
Mentions: The mean Az values, which indicate the performance of each reader, are given in Table 2. The 95% CIs for the mean differences in the Az values between the two image sets and the reading time of each session are also provided. We found that for all three radiologists, the Az values from the MIP images were higher than those Az values from the transaxial images (Fig. 3), however, the difference was significant for only one reader. Overall, the Az values from both image sets were not significantly different. When Grade 3 (indeterminate) or higher were regarded as positive, the sensitivities, specificities, and accuracies were 65%, 86%, and 80% for the transaxial images and 71%, 84%, and 80% for the MIP images, respectively. When Grade 4 (probably positive) was used as the cut-off point, the sensitivities, specificities and accuracies were 47%, 92%, and 80% for the transaxial images and 54%, 92%, and 81% for the MIP images. The mean reading times for the transaxial images and the MIP images were 116 and 126.5 minutes, respectively; these findings were not statistically significant (Wilcoxon-Signed Ranks test, p value = 0.465). The mean numbers of the transaxial and MIP images per patient were 238 and 162, respectively.

Bottom Line: There was no statistical difference in the area under the ROC curve between transaxial images and MIP images for the detection of HSS (0.8375 and 0.8708, respectively; p > 0.05).The mean reading time for the transaxial source images and the MIP images was 116 and 126.5 minutes, respectively.The diagnostic performance of the MIP images for detecting HSS of the coronary arteries is acceptable and this technique's ability to detect HSS is comparable to that of the transaxial source images.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea.

ABSTRACT

Objective: We wanted to compare the transaxial source images with the optimized three plane, thin-slab maximum intensity projection (MIP) images from electrocardiographic (ECG)-gated cardiac CT for their ability to detect hemodynamically significant stenosis (HSS), and we did this by means of performing a receiver operating characteristic (ROC) analysis.

Materials and methods: Twenty-eight patients with a heart rate less than 66 beats per minute and who were undergoing both retrospective ECG-gated cardiac CT and conventional coronary angiography were included in this study. The contrast-enhanced CT scans were obtained with a collimation of 16 x 0.75-mm and a rotation time of 420 msec. The transaxial images were reconstructed at the mid-diastolic phase with a 1-mm slice thickness and a 0.5-mm increment. Using the transaxial images, the slab MIP images were created with a 4-mm thickness and a 2-mm increment, and they covered the entire heart in the horizontal long axis (4 chamber view), in the vertical long axis (2 chamber view) and in the short axis. The transaxial images and MIP images were independently evaluated for their ability to detect HSS. Conventional coronary angiograms of the same study group served as the standard of reference. Four radiologists were requested to rank each image with using a five-point scale (1 = definitely negative, 2 = probably negative, 3 = indeterminate, 4 = probably positive, and 5 = definitely positive) for the presence of HSS; the data were then interpreted using ROC analysis.

Results: There was no statistical difference in the area under the ROC curve between transaxial images and MIP images for the detection of HSS (0.8375 and 0.8708, respectively; p > 0.05). The mean reading time for the transaxial source images and the MIP images was 116 and 126.5 minutes, respectively.

Conclusion: The diagnostic performance of the MIP images for detecting HSS of the coronary arteries is acceptable and this technique's ability to detect HSS is comparable to that of the transaxial source images.

Show MeSH
Related in: MedlinePlus