Ali Hosseini Rivandi MD, Presenter: Nothing to Disclose

Carl Kalon Hoh MD, Abstract Co-Author: Nothing to Disclose

Mahmood F. Mafee MD, Abstract Co-Author: Nothing to Disclose

Nikdokht Farid MD, Abstract Co-Author: Nothing to Disclose

Asae Nozawa MD, Abstract Co-Author: Nothing to Disclose

Sebastian Obrzut MD, Abstract Co-Author: Nothing to Disclose

Michael Kipper MD, Abstract Co-Author: Nothing to Disclose

To evaluate the accuracy of fused FDG-PET/MRI compared to MR spectroscopy in detecting recurrence of primary and metastatic brain tumors in patients treated with radiation therapy and/or surgery.

This retrospective study contains 31 sets of fused FDG-PET/MRI images as well as MR spectroscopy for 23 patients (mean age 52 yrs, range 21 to 72, 11 M and 12 F) with primary WHO grade III and IV brain tumors (N=19 ), primary WHO grade I and II brain tumors (N=2), and metastatic brain tumors (N = 2). All patients were previously treated with radiation therapy and/or surgery. After IV injection of 185 MBq of FDG and 30 min uptake, 3D PET images were acquired with 30 min scan duration. Iterative reconstructions and attenuation correction were performed. Patients underwent a routine MRI of the brain including axial T1and T2, sagittal T1, coronal T2, and fat suppressed post gadolinium axial and coronal T1 images. MR spectroscopy was also performed in all cases using single voxel (35 and 144 msec echoes) and multivoxel (144 msec echo) techniques. The axial PET images were fused to the post gadolinium axial T1 images using the AGFA IMPAX fusion module. FDG-PET and MRI images were interpreted by experienced nuclear medicine physicians and neuroradiologists, respectively. Patients were followed for a minimum of 3 months. The “gold” standard to determine the presence or absence of tumor recurrence was biopsy and/or clinical status of the patient. In a few cases, imaging follow-up with MRI and/or PET was also used to assess tumor recurrence, with special attention to avoiding the diagnostic pitfalls of pseudoprogression and pseudoresponse. The sensitivity, specificity, and accuracy of fused FDG-PET/MRI were then determined and compared to those of MR spectroscopy.  

In evaluation of brain tumor recurrence, fused FDG-PET/MRI had sensitivity of 96%, specificity of 75% and accuracy of 90% (p value = 0.0002). MR spectroscopy had sensitivity of 73%, specificity of 20% and accuracy of 55% (p value not significant).

Our results suggest that fused FDG-PET/MRI may be more sensitive, specific, and accurate than MR spectroscopy in detecting recurrence of primary and metastatic brain tumors. However, further prospective studies are needed to confirm our findings.

Fused FDG-PET/MRI may be more sensitive, specific, and accurate than MR spectroscopy in detecting recurrence of brain tumors

Hosseini Rivandi, A, Hoh, C, Mafee, M, Farid, N, Nozawa, A, Obrzut, S, Kipper, M, Comparison of Fused FDG-PET/MRI with MR Spectroscopy in the Assessment of Brain Tumor Recurrence.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11016403.html