Dear Nuria,


Thanks for your mail. You raise rather a lot of questions, and I'm not really an FDG person!

However, I understand that in your group there is someone called George Kontaxakis ([log in to unmask]) who has worked on FDG-PET.

For your own reading do try John Votaw's _very_ accessible chapter on PET acquisition and analysis in Advances in Neurology, Volume 83 (Functional Imaging in the Epilepsies) which discusses FDG a lot.

You probably have, somewhere in the department, a copy of "Positron Emission Tomography: Basic Science and Clinical Practice" (Eds. Valk PE, Bailey DL, Townsend DW, Maisey MN); Springer London 2003 where Peter Herscovitch's chapter 13 will be useful. Do read his cautionary remarks on changes in the lumped constant in some pathological conditions; TBI may well be one of them.

Similarly, do have a look at Karl Herholz' et al.'s very useful  Neurological PET: Pet in Neuroscience and Clinical Neurology. Karl Herholz, W.D. Heiss, Peter Herscovitch. Springer-Verlag Berlin and Heidelberg 2004.

Finally, "FDG TBI" yields 22 articles and one review; look out in particular for papers where the authors of the classical papers on FDG (e.g. Reivich M et al. Circ Res 1979; Phelps ME et al. Ann Neurol 1979; Huang SC et al. Am J Physiol 1980) are contributing.

And a general point of warning from my limited understanding - you _will_ get global differences between TBI patients and controls, and will have some difficulty if using nonquantified data (e.g. activity images or SUVs)... I don't know whether there has been systematic work on the issue in TBI but found the PPS below.

All the best and good luck,
A

PS: I hope you don't mind me cc-ing my answer to the list.
PPS: I found this in J Head Trauma Rehabil. 2001 Apr;16(2):135-48. Metabolic recovery following human traumatic brain injury based on FDG-PET: time course and relationship to neurological disability. Bergsneider M, Hovda DA, McArthur DL, Etchepare M, Huang SC, Sehati N, Satz P, Phelps ME, Becker DP.:
"In this study, we chose to limit our analysis to the quantitative interpretation of the FDG-PET scans. Qualitative analysis, a practice common to most published PET and SPECT studies in TBI, suffers from potentially being "blind" to marked differences in the global metabolism despite the common appearance of regional changes. Since no apparent suitable "reference" region exists to judge global metabolism (such as the cerebellum), qualitative analysis largely ignores the dynamic nature of cerebral metabolism following TBI. For example, Worley et al 24 studied 22 children following severe TBI (mean age 7 years) with qualitative FDG-PET. Subjects who were awake but not verbal at the time of PET did not have a significantly lower PET score than those functioning at higher levels. FDG-PET was not by itself a significant predictor of outcome when other variables (CT, MRI, and Rancho Los Amigos Cognitive Level) were taken into consideration."

-----Original Message-----
From: Nuria Lull Noguera [mailto:[log in to unmask]]
Sent: 31 March 2006 15:50
To: [log in to unmask]
Subject: PET


  Dear Alexander,

  I'm researching about images of patients with Traumatic Brain Injury. These images are brain PET images. In an e-mail in the SPM list I've read that you talk about "ligand PET". My images are single scan per subject taken at rest condition. I would like to know what is the procedure with your scans and if yo take blood sampling in order to quantify the metabolism.
I am thinking about starting a research with those rest condition PET images, but I'm new into this field so any help would be greatly appreciated.
Your sincerely,
Nuria Lull
Medical Imaging Area - BET (Bioengineering, Electronics and Telemedicine Group)