Diagnostic accuracy of sequential co-registered PET+MR in comparison to PET/CT in local thoracic staging of malignant pleural mesothelioma

Lung Cancer. 2016 Apr:94:40-5. doi: 10.1016/j.lungcan.2016.01.017. Epub 2016 Jan 28.

Abstract

Purpose: To investigate the diagnostic accuracy of sequential co-registered PET+MR (PET+MR) for local staging of malignant pleural mesothelioma (MPM) compared to PET/CT.

Material and methods: In a prospective clinical trial 34 consecutive patients (median age 66 years; range 40-79 years; 1 female, 33 male) with known MPM, who underwent PET/CT and PET+MR exams for either staging or re-staging/follow-up were evaluated. Imaging was conducted using a tri-modality PET/CT-MR set-up (Discovery PET/CT 690, 3T Discovery MR 750w, both GE Healthcare, Waukesha, WI, USA). In 26 cases histopathology served as standard of reference. Two independent readers evaluated images for T and N stage, confidence level (sure to unsure; 1-3) and subjective overall image quality (very good to non-diagnostic; 1-4). Inter-observer agreement of T and N stages (Cohen's kappa) and interclass correlation coefficient (ICC) between PET/CT vs. PET+MR was calculated.

Results: Inter observer agreement for evaluation of T and N Stage in PET/CT images was excellent (k=0.844 and k=0.824, respectively), whereas PET+MR imaging showed substantial agreement in T and N stage (k=0.729 and k=0.691, respectively). The ICC of PET/CT vs. PET+MR for evaluation of both, T and N Stage, was excellent (ICC=0.951 and ICC=0.93, respectively). Diagnostic confidence was scored significantly higher in PET+MR compared to PET/CT (mean score=1.66 and 1.93, respectively; p=0.004). Image quality was diagnostic for all image series. Comparing pT and pN stage vs cT and cN stage (n=26 cases), both imaging modalities showed excellent agreement for T stage (ICCPET+MR=0.888 vs. ICCPET/CT=0.853, respectively) and substantial to moderate agreement for N stage (ICCPET+MR=0.683 vs. ICC=0.595PET/CT, respectively).

Conclusion: Our findings suggest that diagnostic accuracy of PET+MR is comparable to PET/CT for local staging of MPM, whereas radiologists felt significantly more confident staging PET+MR compared to PET/CT images (p=0003), using dedicated sequences.

Keywords: Diagnostic confidence; Malignant pleural mesothelioma; PET/CT; PET/MR; TN staging.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Aged
  • Female
  • Humans
  • Image Processing, Computer-Assisted
  • Lung Neoplasms / diagnosis*
  • Magnetic Resonance Imaging*
  • Male
  • Mesothelioma / diagnosis*
  • Mesothelioma, Malignant
  • Middle Aged
  • Multimodal Imaging
  • Neoplasm Staging
  • Pleural Neoplasms / diagnosis*
  • Positron Emission Tomography Computed Tomography*
  • Positron-Emission Tomography*
  • Reproducibility of Results