Figure 1
Flow diagram of study participants.
* Comprising nonenhanced, pancreatic, and portal venous phases.
CBD: common bile duct; EUS: endoscopic ultrasound; FNA: fine-needle aspiration; CA: cancer antigen.
Table 1
Objective parameters for evaluating pancreatic ductal adenocarcinoma on multi-reconstructed spectral CT images.
| PARAMETERS | PANCREATIC | VMI40 | VMI55 | VMI70 |
|---|---|---|---|---|
| Tumor-to-pancreas attenuation difference (HU) | 77.6 ± 35.9 | 250.2 ± 115.5 | 131.5 ± 59.4 | 78.8 ± 37.4 |
| Tumor-to-pancreas CNR | 2.7 ± 1.4 | 10.6 ± 5.5 | 6.6 ± 3.3 | 4.2 ± 2.2 |
| SNR | ||||
| Celiac trunk | 10.1 ± 3.7 | 26.6 ± 10.9 | 17.7 ± 6.5 | 11.9 ± 3.6 |
| Portal vein | 7.2 ± 3.5 | 41.4 ± 15.0 | 24.3 ± 6.8 | 15.3 ± 3.8 |
| SMA | 11.2 ± 4.4 | 24.5 ± 12.4 | 17.7 ± 8.6 | 12.1 ± 5.1 |
| SMV | 6.4 ± 3.1 | 41.2 ± 20.1 | 24.8 ± 9.5 | 15.5 ± 5.4 |
| CNR | ||||
| Celiac trunk | 16.2 ± 6.0 | 50.6 ± 19.9 | 26.8 ± 12.8 | 15.9 ± 6.7 |
| Portal vein | 8.1 ± 4.1 | 62.1 ± 20.6 | 32.0 ± 12.5 | 19.0 ± 7.6 |
| SMA | 17.9 ± 7.7 | 52.3 ± 41.2 | 28.8 ± 13.3 | 16.8 ± 7.2 |
| SMV | 7.3 ± 5.1 | 60.1 ± 29.4 | 33.1 ± 15.3 | 19.2 ± 8.1 |
[i] Pancreatic: pancreatic-phase; VMI40, 55, 70: virtual monoenergetic image at 40, 55, and 70 keV of the portal venous phase; HU: Hounsfield unit; CNR: contrast-to-noise ratio; SNR: signal-to-noise ratio; SMA: superior mesenteric artery; SMV: superior mesenteric vein.
Figure 2
Box whisker plot of objective parameters for evaluating pancreatic ductal adenocarcinoma on multi-reconstructed spectral CT images.
HU: Hounsfield unit; CNR: contrast-to-noise ratio; SNR: signal-to-noise ratio; Pancreatic: pancreatic-phase; VMI40, 55, 70: virtual monoenergetic image at 40, 55, and 70 keV of the portal venous phase.
Figure 3
CT images of a 72-year-old woman with pancreatic ductal adenocarcinoma (PDAC).
Among the four reconstructed images, VMI55 (C) and VMI40 (D) showed better contrast between the PDAC (arrow), pancreatic parenchyma (asterisk), and pancreatic duct (arrowhead) than the conventional pancreatic phase (A) and VMI70 (B).
PVP: portal venous phase; VMI40, 55, 70: virtual monoenergetic image at 40, 55, and 70 keV of the PVP.
Figure 4
CT images of a 70-year-old woman with pancreatic ductal adenocarcinoma (PDAC).
Among the three reconstructed images, VMI40 (B) and VMI55 of PVP (C) showed better contrast between the PDAC (arrow) and pancreatic parenchyma (asterisk). The invasion of the duodenum by PDAC is more clearly visualized on VMI40 (B) and VMI55 (C) of the PVP than on the conventional pancreatic phase (A). (D) On pathologic evaluation, PDAC invaded (arrowhead) the duodenum (left side of the dashed line) through the muscularis propria and submucosa (hematoxylin and eosin stain, ×2).
PVP: portal venous phase; VMI40, 55, 70: virtual monoenergetic image at 40, 55, and 70 keV of the PVP.
Figure 5
CT images of a 68-year-old man with pancreatic ductal adenocarcinoma (PDAC).
The superior mesenteric artery (arrow) is well visualized on both VMI40 (B) and VMI55 of PVP (C), as well as on the pancreatic phase (A). PDAC (asterisk) and adjacent fat are more clearly demarcated on VMI40 (B) and VMI55 (C) of the PVP than on the pancreatic phase (A). The extent of tumor contact with the superior mesenteric artery (arrowhead) is more clearly visualized on VMI40 (B) and VMI55 (C) of the PVP than on the pancreatic phase.
PVP: portal venous phase; VMI40, 55, 70: virtual monoenergetic image at 40, 55, and 70 keV of the PVP.
Table 2
Subjective parameters for evaluating pancreatic ductal adenocarcinoma on multi-reconstructed spectral CT images.
| SUBJECTIVE PARAMETERS | READER 1 | READER 2 | KAPPA |
|---|---|---|---|
| Tumor conspicuity | |||
| Pancreatic | 2.97 ± 0.93 | 2.48 ± 0.80 | 0.24 |
| VMI40 | 2.44 ± 0.77 | 2.69 ± 0.96 | 0.16 |
| VMI55 | 3.31 ± 0.69 | 2.92 ± 0.95 | 0.16 |
| VMI70 | 2.61 ± 0.70 | 2.58 ± 0.92 | 0.36 |
| Tumor heterogeneity | |||
| Pancreatic | 0.66 ± 0.72 | 0.77 ± 0.68 | 0.49 |
| VMI40 | 1.05 ± 0.68 | 1.31 ± 0.59 | 0.28 |
| VMI55 | 1.00 ± 0.71 | 1.27 ± 0.62 | 0.41 |
| VMI70 | 0.88 ± 0.75 | 1.11 ± 0.59 | 0.48 |
| Tumor size (cm) | |||
| Pancreatic | 4.19 ± 1.73 | 4.45 ± 1.75 | N/A |
| VMI40 | 4.62 ± 2.09 | 4.79 ± 1.81 | N/A |
| VMI55 | 4.56 ± 2.11 | 4.51 ± 1.76 | N/A |
| VMI70 | 4.44 ± 2.17 | 4.62 ± 1.77 | N/A |
| Celiac trunk invasion | |||
| Pancreatic | 0.63 ± 0.87 | 0.48 ± 0.78 | 0.72 |
| VMI40 | 0.67 ± 0.91 | 0.67 ± 0.87 | 0.77 |
| VMI55 | 0.63 ± 0.90 | 0.63 ± 0.86 | 0.76 |
| VMI70 | 0.59 ± 0.90 | 0.58 ± 0.85 | 0.77 |
| Superior mesenteric artery invasion | |||
| Pancreatic | 0.67 ± 0.86 | 0.66 ± 0.78 | 0.71 |
| VMI40 | 0.80 ± 0.89 | 0.78 ± 0.85 | 0.82 |
| VMI55 | 0.83 ± 0.88 | 0.80 ± 0.86 | 0.75 |
| VMI70 | 0.73 ± 0.88 | 0.73 ± 0.84 | 0.79 |
| Splenic artery invasion | |||
| Pancreatic | 0.80 ± 0.89 | 0.91 ± 0.90 | 0.76 |
| VMI40 | 1.13 ± 0.93 | 1.13 ± 0.90 | 0.80 |
| VMI55 | 1.13 ± 0.93 | 1.09 ± 0.90 | 0.78 |
| VMI70 | 1.05 ± 0.92 | 1.02 ± 0.90 | 0.79 |
[i] Pancreatic: pancreatic-phase; VMI40, 55, 70: virtual monoenergetic image at 40, 55, and 70 keV of the portal venous phase; N/A: not available.