Background
This PET/MRI study compared contrast-enhanced MRI,
18
F-FACBC-, and
18
F-FDG-PET in the detection of primary central nervous system lymphomas (PCNSL) in patients before and after high-dose methotrexate chemotherapy. Three immunocompetent PCNSL patients with diffuse large B-cell lymphoma received dynamic
18
F-FACBC- and
18
F-FDG-PET/MRI at baseline and response assessment. Lesion detection was defined by clinical evaluation of contrast enhanced T1 MRI (ce-MRI) and visual PET tracer uptake. SUVs and tumor-to-background ratios (TBRs) (for
18
F-FACBC and
18
F-FDG) and time-activity curves (for
18
F-FACBC) were assessed.
Results
At baseline, seven ce-MRI detected lesions were also detected with
18
F-FACBC with high SUVs and TBRs (SUV
max
:mean, 4.73, TBR
max
: mean, 9.32, SUV
peak
: mean, 3.21, TBR
peak
:mean: 6.30). High TBR values of
18
F-FACBC detected lesions were attributed to low SUV
background
. Baseline
18
F-FDG detected six lesions with high SUVs (SUV
max
: mean, 13.88). In response scans, two lesions were detected with ce-MRI, while only one was detected with
18
F-FACBC. The lesion not detected with
18
F-FACBC was a small atypical MRI detected lesion, which may indicate no residual disease, as this patient was still in complete remission 12 months after initial diagnosis. No lesions were detected with
18
F-FDG in the response scans.
Conclusions
18
F-FACBC provided high tumor contrast, outperforming
18
F-FDG in lesion detection at both baseline and in response assessment.
18
F-FACBC may be a useful supplement to ce-MRI in PCNSL detection and response assessment, but further studies are required to validate these findings.
Trial registration
ClinicalTrials.gov. Registered 15th of June 2017 (Identifier: NCT03188354,
https://clinicaltrials.gov/study/NCT03188354
)....

18F-FACBC and 18F-FDG PET/MRI in the evaluation of 3 patients with primary central nervous system lymphoma: a pilot study

10.1186/s41824-024-00189-6