Dual-phase dual-energy CT in patients with lung cancer: assessment of the additional value of iodine quantification in lymph node therapy response

Eur Radiol. 2014 Aug;24(8):1981-8. doi: 10.1007/s00330-014-3223-9. Epub 2014 Jun 4.

Abstract

Objectives: To investigate the potential contribution of iodine uptake calculation from dual-phase dual-energy CT (DE-CT) for lymph node staging and therapy response monitoring in lung cancer patients.

Methods: Retrospective analysis of 27 patients with non-small cell lung carcinoma (NSCLC), who underwent dual-phase DE-CT before and after chemotherapy, was performed. Iodine uptake (mg/mL) and total iodine uptake (mg) were calculated using prototype software in the early (arterial) and late (venous) post-contrast circulatory phase in 110 mediastinal lymph nodes. The arterial enhancement fraction (AEF) was calculated and compared with lymph node size and response to chemotherapy.

Results: A significant difference of AEF was observed between enlarged (90.4%; 32.3-238.5%) and non-enlarged (72.7%; -37.5-237.5%) lymph nodes (p = 0.044) before treatment onset. A significantly different change of AEF in responding (decrease of 26.3%; p = 0.022) and non-responding (increase of 43.0%; p = 0.031) lymph nodes was demonstrated. A higher value of AEF before treatment was observed in lymph nodes with subsequent favourable response (88.6% vs. 77.7%; p = 0.122), but this difference did not reach statistical significance.

Conclusions: The dual-phase DE-CT examination with quantification of ratio of early and late post-contrast iodine uptake is a feasible and promising method for the functional evaluation of mediastinal lymph nodes including therapy response assessment.

Key points: • Dual-phase DE-CT is beneficial for mediastinal lymph node assessment in NSCLC. • Arterial to venous iodine uptake ratio was higher in enlarged lymph nodes. • Change of arterial enhancement fraction correlated to therapy response.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Carcinoma, Non-Small-Cell Lung / diagnostic imaging*
  • Carcinoma, Non-Small-Cell Lung / secondary
  • Contrast Media / pharmacokinetics
  • Female
  • Humans
  • Iodine / pharmacokinetics*
  • Lung Neoplasms / diagnostic imaging*
  • Lung Neoplasms / metabolism
  • Lung Neoplasms / pathology
  • Lymph Node Excision
  • Lymph Nodes / diagnostic imaging
  • Lymph Nodes / pathology
  • Lymph Nodes / surgery
  • Male
  • Mediastinum
  • Middle Aged
  • Multidetector Computed Tomography / methods*
  • Neoplasm Staging / methods*
  • Radionuclide Imaging
  • Reproducibility of Results
  • Retrospective Studies

Substances

  • Contrast Media
  • Iodine