Can Spectral CT Imaging Improve the Differentiation between Malignant and Benign Solitary Pulmonary Nodules?

• Published in: PloS one 2016-02, Vol.11 (2), p.e0147537-e0147537
• Main Authors: Zhang, Ying, Cheng, Jiejun, Hua, Xiaolan, Yu, Mingji, Xu, Chengdong, Zhang, Feng, Xu, Jianrong, Wu, Huawei
• Format: Article
• Language: English
• Subjects: Adult; Aged; Aged, 80 and over; Benign; Biology and Life Sciences; Biopsy; CAT scans; Computed tomography; Data analysis; Data processing; Diagnosis; Diagnosis, Differential; Differentiation; Female; Humans; Image enhancement; Image processing; Imaging; Iodine; Lung diseases; Lung nodules; Male; Malignancy; Mathematical analysis; Medical diagnosis; Medical imaging; Medicine; Medicine and Health Sciences; Methods; Middle Aged; Morphology; NMR; Nodules; Nuclear magnetic resonance; Parameter sensitivity; Patient care; Patients; Physical Sciences; Radiation Dosage; Radiographic Image Enhancement; Reproducibility of Results; Research and Analysis Methods; ROC Curve; Sensitivity; Solitary Pulmonary Nodule - diagnostic imaging; Solitary Pulmonary Nodule - pathology; Spectra; Tomography, X-Ray Computed - methods
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0147537

To quantitatively assess the value of dual-energy CT (DECT) in differentiating malignancy and benignity of solitary pulmonary nodules. Sixty-three patients with solitary pulmonary nodules detected by CT plain scan underwent contrast enhanced CT scans in arterial phase (AP) and venous phase (VP) with spectral imaging mode for tumor type differentiation. The Gemstone Spectral Imaging (GSI) viewer was used for image display and data analysis. Region of interest was placed on the relatively homogeneous area of the nodule to measure iodine concentration (IC) on iodine-based material decomposition images and CT numbers on monochromatic image sets to generate spectral HU curve. Normalized IC (NIC), slope of the spectral HU curve (λHU) and net CT number enhancement on 70keV images were calculated. The two-sample t-test was used to compare quantitative parameters. Receiver operating characteristic curves were generated to calculate sensitivity and specificity. There were 63 nodules, with 37 malignant nodules (59%) and 26 benign nodules (41%). NIC, λHU and net CT number enhancement on 70keV images for malignant nodules were all greater than those of benign nodules. NIC and λHU had intermediate to high performances to differentiate malignant nodules from benign ones with the areas under curve of 0.89 and 0.86 respectively in AP, 0.96 and 0.89 respectively in VP. Using 0.30 as a threshold value for NIC in VP, one could obtain sensitivity of 93.8% and specificity of 85.7% for differentiating malignant from benign solitary pulmonary nodules. These values were statistically higher than the corresponding values of 74.2% and 53.8% obtained with the conventional CT number enhancement. DECT imaging with GSI mode provides more promising value in quantitative way for distinguishing malignant nodules from benign ones than CT enhancement numbers.