PET-MRI After Radiofrequency Ablation (RFA) or Microwave Ablation (MWA)

Study Overview
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Brief Summary
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The primary objective of this study is to evaluate the ability of PET-MRI and to detect a local site recurrence during the first year of follow-up after RFA or MWA of colorectal liver metastases (CRLM) as compared with contrast enhanced (ce) CT and PET-CT. Standard reference will be clear focal uptake in the rim of the lesion on PET-CT, possibly in combination with histology (when available) or clinical follow-up. Secondary outcomes are the inter-observer variability, the ability to diagnose new intrahepatic lesions and in what way PET-MRI is able to influence future treatment compared to PET-CT and ceCT. The patients satisfaction concerning the PET-MRI will be examined with a questionnaire.

Detailed Description
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All included patients will routinely undergo follow-up with 3 monthly ceCT of the liver and PET-CT in the first year after RFA/MWA of CRLM according to standard of care in our hospital. Patients are asked to undergo an additional PET-MRI of the liver on the same day in the first year (in total 4 scans). The PET-MRI is obtained before the PET-CT. The 18F-2-fluoro-2-deoxy-D-glucose fluorodeoxyglucose (FDG) used for PET-CT and PET-MRI are alike and one injection is sufficient. The PET-CT has to be made within 150 minutes after FDG injection. Anonymous PET-MRI results are independently reviewed by 2 experienced radiologists and 2 nuclear medicine physicians twice, with a time-interval of at least two weeks between the first and second review. Based on these results, treatment decisions will be compared for any change in decision making. The evaluate inter-observer variability we will ask the two nuclear medicine physicians and two radiologist to assess all results and score local and intrahepatic tumor progression. Results of the first and second evaluation will be compared to determine inter observer agreement using Cohen's Kappa. Local recurrence and new lesions will be scored on a separate form with standard criteria. The reports on LSR will be scored as follows: Normal: when the reviewer is sure that no tumor recurrence is present in the ablation zone. Probably benign: FDG is enhanced, but compatible with post-ablation inflammation or rim-like characteristics on MRI images (not focal!) Equivocal: there is doubt whether the enhanced FDG, CT- or MRI features are due to tumor recurrence or inflammation Probably malign: when the reviewer is sure about local recurrence in the ablation zone. Size and location will also be reported. The reports on new intrahepatic lesions will be scored as follows: Normal: no new intrahepatic disease outside 1cm of the ablation zone Equivocal: doubt about the malignant origin of a lesion Probably malign: new intrahepatic tumor not within 1cm of the ablation zone, including size and location. The results of all scans by the reviewers, in the way as described above, will be compared to each other to determine the inter-observer variability using Cohen's Kappa. A questionnaire with 7 questions is completed at the end of one year follow-up to determine patients experience with PET-MRI and PET-CT. The questions will be in Dutch, but are translated below for this purpose. Patients can answer on a scale 1-5 and n/a. The PET-MRI was less burdensome than PET-CT The PET-MRI was more bothersome than I expected PET-MRI is more comfortable than PET-CT If I could choose, I would rather undergo PET-MRI than PET-CT The noise of the PET-MRI was annoying The fact that PET-MRI takes longer than PET-CT isn't an issue for me I would rather undergo a PET-MRI than a PET-CT if results are proven to be equal

Official Title
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The Use of PET-MRI in the Follow-up of RFA and MWA Treated Colorectal Liver Metastases

Conditions
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Liver Neoplasms, Local Neoplasm Recurrence

Intervention / Treatment
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* Other: Gadolinium


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Histological or cytological documentation of primary colorectal tumor Radiological or histological prove of one or more CRLM or radiological proof of a LSR after previous RFA/MWA treatment for CRLM CRLM or LSR treated with RFA/MWA or RFA/MWA in combination with resection Follow-up imaging performed in Free University (VU) University Medical Center Age ³ 18 years Life expectancy of at least 1 year estimated glomerular filtration rate (eGFR) > 60 or hydration according to protocol before scanning Written informed consent. Exclusion Criteria: cirrhosis or steatosis of the liver Chemotherapy ≤ 6 weeks before scanning (during the entire study) Pregnant or breast-feeding subjects Allergy to contrast media Patients developing recurrent intrahepatic disease that require resection of the ablated lesion eGFR < 60, unless hydration according to protocol is possible General exclusion criteria to undergo MRI claustrophobia intracranial clips any implanted stimulation device (eg. internal cardioverter defibrillator/pacemaker, cochlear implant) intra-ocular metal splinters or metal clips Metal artificial heart valve Bone prosthesis < 6 weeks inability to lie still for 30 minutes orthopnea intestinal video capsule Metal intra auricular prosthesis all other prosthesis or piercings should be removed.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| PET-MRI<br>Twenty patients with RFA/MWA for CRLM or RFA/MWA of recurrent liver lesions after prior local treatment of CRLM and are eligible to undergo MRI-scanning are included when they have adequate renal function. Patients that do not meet inclusion criteria for undergoing an MRI scan are excluded. | Other: Gadolinium<br>* All patients will undergo PET-MRI additional to the PET-CT they routinely undergo. All patients will be administered Gadolinium for the PET-MRI scan. This is an extra intervention than they would normally undergo.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Local site recurrence (LSR) detection | The primary objective of this study is to evaluate the ability of PET-MRI and diffusion and contrast enhanced MRI to detect LSR during the first year of follow-up after RFA treatment of CRLM as compared with ceCT and PET-CT. Standard reference will be clear focal uptake in the rim of the lesion on PET-CT, possibly in combination with histology (when available) or clinical follow-up. | 1 year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Detection new intrahepatic lesions | the ability of PET-MRI to diagnose smaller new intrahepatic lesions than PET-CT and ceCT | 1 year | 
| inter-observer variability | Hard copy data sets of all PET-MRI and PET-CT scans, with no patient information, random order, independently reviewed by 2 experienced radiologists and 2 nuclear medicine physicians twice (reviewers blinded to the images and results of the other imaging modalities and blinded to the final outcome of patients), with a time-interval of at least two weeks between the first and second review. These scans are scored on a standardized form (explained in the section 'detailed description'). The outcomes between the different reviewers of the same scan are noted and compared to each other. Inter observer variability is determined using Cohen's Kappa. | 1 year | 
| Influence on decision making | in what way PET-MRI is able to change future treatment compared to PET-CT and ceCT | 1 year | 
| Patients experience with PET-CT and PET-MRI | A questionnaire with 7 questions is completed at the end of one year follow-up to determine patients experience with PET-MRI and PET-CT. This is done to get an idea of the possible objections and wishes of all patients. Results will be described. The questions will be in Dutch, but are translated below for this purpose. Patients can answer on a scale 1-5 and n/a. The PET-MRI was less burdensome than PET-CT The PET-MRI was more bothersome than I expected PET-MRI is more comfortable than PET-CT If I could choose, I would rather undergo PET-MRI than PET-CT The noise of the PET-MRI was annoying The fact that PET-MRI takes longer than PET-CT isn't an issue for me I would rather undergo a PET-MRI than a PET-CT if results are proven to be equal | end of one year follow-up | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Magnetic Resonance Imaging, FDG-PET, Radiofrequency Ablation