Table 1.
Five-point Scoring System of Different Image Quality Characteristics for Observer Study.
Fig 1.
Quantitative analysis of RD-CTPA being reconstructed with FBP, iDose4 and IMR.
Error bars represent the 95% confidence interval.
Fig 2.
Objective image noise reduction with application of iDose4 and IMR compared with FBP.
Objective image noise of this RD-CTPA significantly decreased from FBP (97 HU) to iDoseL4 (70 HU), to iDoseL6 (54 HU), to IMR-BR1 (38 HU), to IMR-BR2 (32) and IMR-BR3 (23 HU).
Fig 3.
Qualitative analysis of RD-CTPA being reconstructed with FBP, iDose4 and IMR.
The plots show the mean scores for subjective image quality, subjective image noise and blotchy image appearance. Error bars represent the 95% confidence interval. Subjective 5-point grading scale (1 indicating worst through 5 indicating best).
Fig 4.
Image quality, image noise and image appearance of RD-CTPA being reconstructed with FBP, iDose4 and IMR.
Transverse RD-CTPA image reconstructed with FBP, iDoseL4, iDoseL6, IMR-BR1, IMR-BR2 and IMR-BR3. Subjective image quality and image noise improved with the application of iDose4 and IMR compared with FBP. Simultaneously, blotchy appearance increases moderately with application of iterative reconstruction.
Fig 5.
Qualitative analysis of conspicuity of pulmonary embolism in central/lobar, segmental and subsegmental pulmonary arteries.
The plots show the mean subjective image scores (error bars represent the 95% confidence interval). Subjective 3-point grading scale: 1, subtle, may be an artifact; 2, sufficient, filling defect definable; and 3, excellent, filling defect clearly definable.
Fig 6.
Conspicuity of lobar pulmonary embolism in RD-CTPA being reconstructed FBP, iDose4 and IMR.
Transverse RD-CTPA image reconstructed with FBP, iDoseL4, iDoseL6, IMR-BR1, IMR-BR2 and IMR -BR3 demonstrating a right-sided pulmonary embolism with filling-defect in the right lower lobe artery being obscured at FBP. With application of the iterative reconstruction algorithms iDose4 and IMR a significant decrease of image noise and streak artifacts was achieved, enabling a better conspicuity of the filling defect with IMR and to lower extent also with iDose4 compared to FBP.
Fig 7.
Conspicuity of segmental pulmonary embolism in RD-CTPA being reconstructed FBP, iDose4 and IMR.
Transverse RD-CTPA image reconstructed with FBP, iDoseL4, iDoseL6, IMR-BR1, IMR-BR2 and IMR -BR3 demonstrating a right-sided segmental pulmonary embolism. Conspicuity of the filling defect improved with application of the iterative reconstruction algorithms iDose4 and IMR.
Fig 8.
Conspicuity of subsegmental pulmonary embolism in RD-CTPA being reconstructed FBP, iDose4 and IMR.
Detailed enlargement of a subsegmental pulmonary artery with embolus. RD-CTPA image reconstructed with FBP, iDoseL4, iDoseL6, IMR-BR1, IMR-BR2 and IMR -BR3. Whereas the filling defect is well definable in FBP images, it’s conspicuity slightly decreases with iDose4 and markedly decreases with IMR.