Article Figures & Data
Figures
- Fig 1.
Photograph (A) and schematic drawing (B) of the anthropomorphic vascular phantom used in this study. The phantom was designed to simulate the intracranial arteries with a total of 32 aneurysms. Of 32 aneurysms, 15 had a bleb with diameter of 2 mm.
- Fig 2.
ROC curves for the detection of simulated aneurysmal blebs with 3 different contrast material concentrations: 300 mg I/mL (A), 150 mg I/mL (B), and 100 mg I/mL (C). For each contrast material concentration, graph shows the 3 composite ROC curves generated from the pooled data of the 7 observers’ results with the standard- (solid line) and low-dose modes of FPD (dashed line) and the conventional-dose mode of I.I.-TV (dotted line) systems.
- Fig 3.
2D DSA from the left anterior oblique view at 300 mg I/mL obtained with standard-dose mode of FPD system (A), with low-dose mode of FPD system (B), and with conventional-dose mode of I.I.-TV system shows blebs (arrows) (C). For the depiction of aneurysmal blebs, there is no particular difference among the 3 dose modes.
- Fig 4.
2D DSA from the left anterior oblique view at 100 mg I/mL obtained with standard-dose mode of FPD (A), with low-dose mode of FPD (B), and with conventional-dose mode of I.I.-TV system shows blebs (arrows) (C). For the depiction of aneurysmal blebs, the images obtained with both dose modes of FPD system are superior to those obtained with the I.I.-TV system.
Tables
Feature FPD system I.I.-TV system Total filtration 3 mm of Al + 0.3 mm of Cu 3 mm of Al Additional filtration None None Frame rate Cine mode 30 fps 30 fps Fluoroscopy mode 15 fps 15 fps Image matrix format 1440 × 1440 1024 × 1024 Field of view 9 inches 12 inches Note:—FPD indicates flat panel detector; I.I.-TV, image intensifier television; fps, frames per second.
- Table 2:
Subjective evaluation for the 2D DSA regarding the depiction of simulated aneurysms
Contrast Material Concentration & Dose Mode Score for Image Quality P 5 4 3 2 1 Mean ± SD* 300 mgI/mL Standard-dose mode of FPD system 57 0 0 0 0 5.00 ± 0.00** .038 Low-dose mode of FPD system 57 0 0 0 0 5.00 ± 0.00** .038 Conventional-dose mode of I.I.-TV system 52 3 2 0 0 4.88 ± 0.43 150 mgI/mL Standard-dose mode of FPD system 55 1 1 0 0 4.95 ± 0.29** <.001 Low-dose mode of FPD system 52 4 1 0 0 4.90 ± 0.36** <.001 Conventional-dose mode of I.I.-TV system 41 10 5 1 0 4.60 ± 0.73 100 mgI/mL Standard-dose mode of FPD system 41 12 4 0 0 4.65 ± 0.61** <.001 Low-dose mode of FPD system 39 13 5 0 0 4.60 ± 0.65** <.001 Conventional-dose mode of I.I.-TV system 1 15 26 13 2 3.00 ± 0.85 Note:—DSA indicates digital subtraction angiography; FPD, flat panel detector; I.I.-TV, image intensifier television. Data are mean ± SD of scores for image quality evaluated using a 5-point scale (1, clearly visualized; 2, good; 3, reasonably good; 4, poor; 5, very poor)
** Significantly higher to I.I.-TV system (the Wilcoxon signed rank test).
- Table 3:
Diagnostic performance according of each observer regarding the detection of the simulated aneurysmal blebs
Contrast Material Concentration & Dose Mode Observer Mean Az 1 2 3 4 5 6 7 300 mgI/mL Standard-dose mode of FPD system 0.93 0.91 0.89 0.92 0.91 0.92 0.94 0.92 Low-dose mode of FPD system 0.89 0.89 0.91 0.92 0.92 0.94 0.95 0.92 Conventional-dose mode of I.I.-TV system 0.92 0.91 0.86 0.98 0.87 0.95 0.90 0.91 150 mgI/mL Standard-dose mode of FPD system 0.81 0.79 0.83 0.83 0.83 0.80 0.82 0.82 Low-dose mode of FPD system 0.83 0.79 0.85 0.82 0.83 0.85 0.84 0.83 Conventional-dose mode of I.I.-TV system 0.80 0.78 0.85 0.81 0.82 0.84 0.82 0.82 100 mgI/mL Standard-dose mode of FPD system 0.84 0.88 0.87 0.80 0.93 0.87 0.80 0.86* Low-dose mode of FPD system 0.84 0.88 0.86 0.79 0.93 0.87 0.79 0.85* Conventional-dose mode of I.I.-TV system 0.67 0.55 0.54 0.57 0.55 0.54 0.52 0.56 Note:—Az indicates areas under the receiver operating characteristic curve; FPD, flat panel detector; I.I.-TV, image intensifier television.
* Significantly higher to I.I.-TV system (P < .01).
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