Simultaneous whole-body time-of-flight 18F-FDG PET/MRI: A pilot study comparing SUVmax with PET/CT and assessment of MR image quality

Andrei Iagaru, Erik Mittra, Ryogo Minamimoto, Mehran Jamali, Craig Levin, Andrew Quon, Garry Gold, Robert Herfkens, Shreyas Vasanawala, Sanjiv Sam Gambhir, Greg Zaharchuk

Research output: Contribution to journalArticlepeer-review

63 Scopus citations


Purpose: The recent introduction of hybrid PET/MRI scanners in clinical practice has shown promising initial results for several clinical scenarios. However, the first generation of combined PET/MRI lacks time-of-flight (TOF) technology. Herewe report the results of the first patients to be scanned on a completely novel fully integrated PET/MRI scanner with TOF.

Materials and Methods: We analyzed data from patients who underwent a clinically indicated 18F FDG PET/CT, followed by PET/MRI. Maximum standardized uptake values (SUVmax) were measured from 18F FDG PET/MRI and 18F FDG PET/CT for lesions, cerebellum, salivary glands, lungs, aortic arch, liver, spleen, skeletal muscle, and fat. Two experienced radiologists independently reviewed the MR data for image quality.

Results: Thirty-six patients (19 men, 17 women, mean [±standard deviation] age of 61 ± 14 years [range: 27-86 years]) with a total of 69 discrete lesions met the inclusion criteria. PET/CT images were acquired at a mean (±standard deviation) of 74 ± 14 minutes (range: 49-100 minutes) after injection of 10 ± 1 mCi (range: 8-12 mCi) of 18F FDG. PET/MRI scans started at 161 ± 29 minutes (range: 117 - 286 minutes) after the 18F FDG injection. All lesions identified on PET from PET/CTwere also seen on PET from PET/MRI. The mean SUVmax values were higher from PET/MRI than PET/CT for all lesions. No degradation of MR image quality was observed.

Conclusion: The data obtained so far using this investigational PET/MR system have shown that the TOF PET system is capable of excellent performance during simultaneous PET/MR with routine pulse sequences. MR imaging was not compromised. Comparison of the PET images from PET/CT and PET/MRI show no loss of image quality for the latter. These results support further investigation of this novel fully integrated TOF PET/MRI instrument.

Original languageEnglish (US)
Pages (from-to)1-8
Number of pages8
JournalClinical Nuclear Medicine
Issue number1
StatePublished - Jan 14 2015
Externally publishedYes


  • CT
  • MRI
  • PET
  • Simultaneous
  • TOF

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging


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