Gastric Cancer Staging with Dual Energy Spectral CT Imaging

<div><p>Purpose</p><p>To evaluate the clinical utility of dual energy spectral CT (DEsCT) in staging and characterizing gastric cancers.</p><p>Materials and Methods</p><p>96 patients suspected of gastric cancers underwent dual-phasic scans (arterial phase (AP) and portal venous phase (PP)) with DEsCT mode. Three types of images were reconstructed for analysis: conventional polychromatic images, material-decomposition images, and monochromatic image sets with photon energies from 40 to 140 keV. The polychromatic and monochromatic images were compared in TNM staging. The iodine concentrations in the lesions and lymph nodes were measured on the iodine-based material-decomposition images. These values were further normalized against that in aorta and the normalized iodine concentration (nIC) values were statistically compared. Results were correlated with pathological findings.</p><p>Results</p><p>The overall accuracies for T, N and M staging were (81.2%, 80.0%, and 98.9%) and (73.9%, 75.0%, and 98.9%) determined with the monochromatic images and the conventional kVp images, respectively. The improvement of the accuracy in N-staging using the keV images was statistically significant (p<0.05). The nIC values between the differentiated and undifferentiated carcinoma and between metastatic and non-metastatic lymph nodes were significantly different both in AP (p = 0.02, respectively) and PP (p = 0.01, respectively). Among metastatic lymph nodes, nIC of the signet-ring cell carcinoma were significantly different from the adenocarcinoma (p = 0.02) and mucinous adenocarcinoma (p = 0.01) in PP.</p><p>Conclusion</p><p>The monochromatic images obtained with DEsCT may be used to improve the N-staging accuracy. Quantitative iodine concentration measurements may be helpful for differentiating between differentiated and undifferentiated gastric carcinoma, and between metastatic and non-metastatic lymph nodes.</p></div

Same patient as Figure 3.

<p>Monochromatic image in portal phase demonstrated striation enhancement of blurring and wide reticular strands surrounding the outer border (arrow heads) of the tumor staged as T3 which was proved by histology.</p

Receiver operating characteristic curves for differentiating metastatic and non-metastatic lymph node in portal phase.

<p>Receiver operating characteristic curves for differentiating metastatic and non-metastatic lymph node in portal phase.</p

Water-based material decomposition images for a 62-year-old man with signet ring cell carcinoma obtained with dual energy spectral scan mode.

<p>Water-based material decomposition images for a 62-year-old man with signet ring cell carcinoma obtained with dual energy spectral scan mode.</p

Accuracies, sensitivities and specificities for N staging using kVp images (Group A) and optimal monochromatic images (Group B) with histological examination as the reference standard.

<p>Accuracies, sensitivities and specificities for N staging using kVp images (Group A) and optimal monochromatic images (Group B) with histological examination as the reference standard.</p

Accuracies, sensitivities and specificities for the distinction of N0 vs. N+ using kVp images (Group A) and optimal monochromatic images (Group B) with histological examination as the reference standard among patients with non metastatic disease.

<p>Accuracies, sensitivities and specificities for the distinction of N0 vs. N+ using kVp images (Group A) and optimal monochromatic images (Group B) with histological examination as the reference standard among patients with non metastatic disease.</p

GSI scatterplot images water and iodine concentration plots for the same patient as Figure 11.

<p>GSI scatterplot images water and iodine concentration plots for the same patient as <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0053651#pone-0053651-g011" target="_blank">Figure 11</a>.</p

Iodine-based material decomposition images of same patient as Figure 11.

<p>The iodine concentration of the primary lesion (black arrows) was 37.77(mg/mL), non-metastatic lymph node (arrow head) was 26.00 mg/mL, and metastatic lymph node (white arrow) was 12.93 mg/ml.</p

Accuracies, sensitivities and specificities for T staging using kVp images (Group A) and optimal monochromatic images (Group B) with histological examination as the reference standard.

<p>Accuracies, sensitivities and specificities for T staging using kVp images (Group A) and optimal monochromatic images (Group B) with histological examination as the reference standard.</p

Comparison of nIC in AP and PP with clinic-pathological characteristics of the patients including histological classification and metastic or nonmetastatic lymph nodes.

<p>Comparison of nIC in AP and PP with clinic-pathological characteristics of the patients including histological classification and metastic or nonmetastatic lymph nodes.</p