The halo-artifact leading to a potential false negative result of 68Ga-PSMA PET-CT.  A case report. — ASN Events
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  3. The halo-artifact leading to a potential false negative result of 68Ga-PSMA PET-CT.  A case report.

The halo-artifact leading to a potential false negative result of 68Ga-PSMA PET-CT.  A case report. (#73)

Lilian Y.I. Yamaga 1 , Marcelo L. Cunha 1 , Jairo Wagner 1 , Marcelo G, Funari 1
  1. Hospital Israelita Albert Einstein, São Paulo, Brazil

68Ga-PSMA is a highly promising  tracer for the evaluation of patients with prostate cancer. It has been demonstrated  a high detection rate and specificity of 68Ga-PSMA PET-CT in the diagnosis  of tumor recurrence after prostatectomy, radiotherapy or other local treatment modalities. 

More recently,   PET-MR hybrid systems  have been evaluated in prostate cancer biochemical recurrence  using 68Ga-PSMA.  In a significant number of patients,  an artifact of reduced PET signal ("halo") around the bladder and/or kidney led to limitations concerning visualization of prostate cancer local recurrence or metastasis.  Interestingly, this photopenic artifact  was described  in PET-MR  but  not  in PET-CT imaging. 

We report a case of  recurrent prostate cancer  evaluated by  68Ga- PMSA PET-CT in which most of the metastatic lymph nodes were missed by the images performed 1 hour after tracer injection  due to the halo-artifact and were correctly detected  in the PET-CT images  obtained  2 hours  after injection. 

This  report  demonstrates that halo-artifact which  occurs  in 68GaPSMA PET/CT  must be recognized in order to reduce the possibility of a false-negative diagnosis of recurrent prostate cancer.

  1. Afshar-Oromich A., Haberkorn,U., Schlemmer H.P., Fenchel M., Eder M. et al. Comparison of PET-CT and PET-MR hybrid systems using a 68Ga-labelled PSMA ligand for the diagnosis of recurrent prostate cancer: initial experience. Eur J Nucl Med Mol Imaging (2014) 41:887-97.