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The use of PET-MRI in the follow-up after radiofrequency- and microwave ablation of colorectal liver metastases

Karin Nielsen1, Hester J Scheffer2, Indra C Pieters2, Aukje AJM van Tilborg2, Jan-Hein TM van Waesberghe2, Daniela E Oprea-Lager2, Martijn R Meijerink2, Geert Kazemier1, Otto S Hoekstra2, Hermien WH Schreurs3, Colin Sietses4, Sybren Meijer1, Emile FI Comans2 and Petrousjka MP van den Tol1*

Author Affiliations

1 Department of Surgery, VU University Medical Center, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands

2 Radiology & Nuclear Medicine, VU University Medical Center, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands

3 Department of Surgery, Medical Center Alkmaar, Postbus 501, 1800 AM Alkmaar, The Netherlands

4 Department of Surgery, Gelderse Vallei, Willy Brandtlaan 10, 6716 RP Ede, The Netherlands

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BMC Medical Imaging 2014, 14:27  doi:10.1186/1471-2342-14-27

Published: 8 August 2014



Thermal ablation of colorectal liver metastases (CRLM) may result in local progression, which generally appear within a year of treatment. As the timely diagnosis of this progression allows potentially curative local treatment, an optimal follow-up imaging strategy is essential. PET-MRI is a one potential imaging modality, combining the advantages of PET and MRI. The aim of this study is evaluate fluorine-18 deoxyglucose positron emission tomography (FDG) PET-MRI as a modality for detection of local tumor progression during the first year following thermal ablation, as compared to the current standard, FDG PET-CT. The ability of FDG PET-MRI to detect new intrahepatic lesions, and the extent to which FDG PET-MRI alters clinical management, inter-observer variability and patient preference will also be included as secondary outcomes.


Twenty patients undergoing treatment with radiofrequency or microwave ablation for (recurrent) CRLM will be included in this prospective trial. During the first year of follow-up, patients will be scanned at the VU University Medical Center at 3-monthly intervals using a 4-phase liver CT, FDG PET-CT and FDG PET-MRI. Patients treated with chemotherapy <6 weeks prior to scanning or with a contra-indication for MRI will be excluded. MRI will be performed using both whole body imaging (mDixon) and dedicated liver sequences, including diffusion-weighted imaging, T1 in-phase and opposed-phase, T2 and dynamic contrast-enhanced imaging. The results of all modalities will be scored by 4 individual reviewers and inter-observer agreement will be determined. The reference standard will be histology or clinical follow-up. A questionnaire regarding patients’ experience with both modalities will also be completed at the end of the follow-up year.


Improved treatment options for local site recurrences following CRLM ablation mean that accurate post-ablation staging is becoming increasingly important. The combination of the sensitivity of MRI as a detection method for small intrahepatic lesions with the ability of FDG PET to visualize enhanced metabolism at the ablation site suggests that FDG PET-MRI could potentially improve the accuracy of (early) detection of progressive disease, and thus allow swifter and more effective decision-making regarding appropriate treatment.

Trial registration

Trial registration number: NCT01895673

Radiofrequency ablation; Liver neoplasms/secondary; Neoplasm recurrence; Local; Liver neoplasms/surgery; FDG-PET; PET-MRI; Magnetic resonance imaging/methods; Microwave ablation