Utility of the iodine overlay technique and virtual nonenhanced images for the preoperative T staging of colorectal cancer by dual-energy CT with tin filter technology

• Published in: PloS one 2014-12, Vol.9 (12), p.e113589-e113589
• Main Authors: Chen, Chiao-Yun, Hsu, Jui-Sheng, Jaw, Twei-Shiun, Wu, Deng-Chyang, Shih, Ming-Chen Paul, Lee, Chien-Hung, Kuo, Chao-Hung, Chen, Yi-Ting, Lai, Ming-Lai, Liu, Gin-Chung
• Format: Article
• Language: English
• Subjects: Adult; Aged; Aged, 80 and over; Cancer; Colonography, Computed Tomographic - methods; Colorectal cancer; Colorectal carcinoma; Colorectal Neoplasms - diagnostic imaging; Colorectal Neoplasms - pathology; CT imaging; Diagnostic systems; Female; Humans; Image acquisition; Image enhancement; Image reconstruction; Iodine; Male; Medical imaging; Medicine and Health Sciences; Metastases; Methods; Middle Aged; Neoplasm Staging; Noise; Patients; Preoperative Period; Radiation; Radiation dosage; Radiation effects; Radiography, Dual-Energy Scanned Projection - methods; Research and Analysis Methods; Retrospective Studies; Signal-To-Noise Ratio; Statistical analysis; Technology assessment; Trace Elements; Tumors; Variance analysis
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0113589

To evaluate the diagnostic accuracy and the potential radiation dose reduction of dual-energy CT (DECT) for tumor (T) staging of colorectal cancer (CRC) using iodine overlay (IO) and virtual nonenhanced (VNE) images. This retrospective study included 103 consecutive patients who underwent nonenhanced CT and enhanced DECT for preoperative CRC staging. Enhanced weighted-average (WA), IO and VNE images were reconstructed from enhanced 80 kVp and Sn140 kVp scans. Two radiologists assessed image qualities of the true nonenhanced (TNE) and VNE images. For T-staging, another two radiologists independently interpreted all scans in two separate reading sessions: in the first session, only images derived from the single phase DECT acquisition (IO and VNE images) were read. In the second reading session after 30 to 50 (average:42) days, the same assessment was again performed with the TNE and enhanced WA images thereby simulating conventional dual-phase single-energy CT. The tumor node metastasis (TNM) system was used for staging with histopathologic reports as gold standard. Analysis of variance was used for statistical analysis. The signal-to-noise ratios (SNRs) of the tumors and normal reference tissues showed significant correlation between the TNE and VNE images (P