Assessment of metastatic colorectal cancer with hybrid imaging: comparison of reading performance using different combinations of anatomical and functional imaging techniques in PET/MRI and PET/CT in a short case series

Eur J Nucl Med Mol Imaging. 2016 Jan;43(1):123-132. doi: 10.1007/s00259-015-3137-z. Epub 2015 Jul 31.

Abstract

Purpose: The purpose was to investigate the diagnostic performance of different combinations of anatomical and functional imaging techniques in PET/MRI and PET/CT for the evaluation of metastatic colorectal cancer lesions.

Methods: Image data of 15 colorectal cancer patients (FDG-PET/CT and subsequent FDG-PET/MRI) were retrospectively evaluated by two readers in five reading sessions: MRI (morphology) alone, MRI/diffusion-weighted MRI (DWI), MRI/PET, MRI/DWI/PET; and PET/CT. Diagnostic performance of lesion detection with each combination was assessed in general and organ-based. The reference standard was given by histology and/or follow-up imaging. Separate analysis of mucinous tumours was performed.

Results: One hundred and eighty lesions (110 malignant) were evaluated (intestine n = 6, liver n = 37, lymph nodes n = 55, lung n = 4, and peritoneal n = 74). The overall lesion-based diagnostic accuracy was 0.46 for MRI, 0.47 for MRI/DWI, 0.57 for MRI/PET, 0.69 for MRI/DWI/PET and 0.66 for PET/CT. In the organ-based assessment, MRI/DWI/PET showed the highest accuracy for liver metastases (0.74), a comparable accuracy to PET/CT in peritoneal lesions (0.55), and in lymph node metastases (0.84). The accuracy in mucinous tumour lesions was limited in all modalities (MRI/DWI/PET = 0.52).

Conclusions: PET/MRI including DWI is comparable to PET/CT in the evaluation of colorectal cancer metastases, with a markedly higher accuracy when using combined imaging data than the modalities separately. Further improvement is needed in the imaging of peritoneal carcinomatosis and mucinous tumours.

Keywords: Colorectal cancer; Computed tomography imaging; Diffusion-weighted imaging; Magnetic resonance imaging; Positron emission tomography.

MeSH terms

  • Adolescent
  • Adult
  • Child
  • Colorectal Neoplasms / diagnosis*
  • Colorectal Neoplasms / diagnostic imaging
  • Colorectal Neoplasms / pathology*
  • Diffusion Magnetic Resonance Imaging*
  • Female
  • Fluorodeoxyglucose F18
  • Humans
  • Male
  • Middle Aged
  • Multimodal Imaging*
  • Neoplasm Metastasis
  • Positron-Emission Tomography*
  • Retrospective Studies
  • Tomography, X-Ray Computed*
  • Young Adult

Substances

  • Fluorodeoxyglucose F18