Solitary pulmonary nodule on helical dynamic CT scans: analysis of the enhancement patterns using a computer-aided diagnosis (CAD) system

Korean J Radiol. 2008 Sep-Oct;9(5):401-8. doi: 10.3348/kjr.2008.9.5.401.


Objective: We wanted to investigate the usefulness of a computer-aided diagnosis (CAD) system in assisting radiologists to diagnosis malignant solitary pulmonary nodules (SPNs), as compared with diagnosing SPNs with using direct personal drawing.

Materials and methods: Forty patients with SPNs were analyzed. After the pre-contrast scan was performed, an additional ten series of post-contrast images were obtained at 20-second intervals. Two investigators measured the attenuation values of the SPNs: a radiologist who drew the regions of interest (ROIs), and a technician who used a CAD system. The Bland and Altman plots were used to compare the net enhancement between a CAD system and direct personal drawing. The diagnostic characteristics of the malignant SPNs were calculated by considering the CAD and direct personal drawing and with using Fisher's exact test.

Results: On the Bland and Altman plot, the net enhancement difference between the CAD system and direct personal drawing was not significant (within +/- 2 standard deriation). The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of diagnosing malignant SPNs using CAD was 92%, 85%, 75%, 96% and 88%, respectively. The sensitivity, specificity, PPV, NPV and accuracy of diagnosing malignant SPNs using direct drawing was 92%, 89%, 79%, 92% and 88%, respectively.

Conclusion: The CAD system was a useful tool for diagnosing malignant SPNs.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Aged
  • Contrast Media
  • Diagnosis, Computer-Assisted / methods*
  • Diagnosis, Differential
  • Female
  • Humans
  • Iohexol / analogs & derivatives
  • Lung Neoplasms / diagnostic imaging*
  • Male
  • Middle Aged
  • Predictive Value of Tests
  • Radiographic Image Enhancement / methods*
  • Retrospective Studies
  • Sensitivity and Specificity
  • Solitary Pulmonary Nodule / diagnostic imaging*
  • Tomography, Spiral Computed / methods*


  • Contrast Media
  • Iohexol
  • iopromide