Increased Brain Fatty Acid Uptake in Metabolic Syndrome

OBJECTIVE: To test whether brain fatty acid uptake is enhanced in obese subjects with metabolic syndrome (MS) and whether weight reduction modifies it. RESEARCH DESIGN AND METHODS: We measured brain fatty acid uptake in a group of 23 patients with MS and 7 age-matched healthy control subjects during fasting conditions using positron emission tomography (PET) with [(11)C]-palmitate and [(18)F]fluoro-6-thia-heptadecanoic acid ([(18)F]-FTHA). Sixteen MS subjects were restudied after 6 weeks of very low calorie diet intervention. RESULTS: At baseline, brain global fatty acid uptake derived from [(18)F]-FTHA was 50% higher in patients with MS compared with control subjects. The mean percentage increment was 130% in the white matter, 47% in the gray matter, and uniform across brain regions. In the MS group, the nonoxidized fraction measured using [(11)C]-palmitate was 86% higher. Brain fatty acid uptake measured with [(18)F]-FTHA-PET was associated with age, fasting serum insulin, and homeostasis model assessment (HOMA) index. Both total and nonoxidized fractions of fatty acid uptake were associated with BMI. Rapid weight reduction decreased brain fatty acid uptake by 17%. CONCLUSIONS: To our knowledge, this is the first study on humans to observe enhanced brain fatty acid uptake in patients with MS. Both fatty acid uptake and accumulation appear to be increased in MS patients and reversed by weight reduction

Brain acetylcholinesterase activity in mild cognitive impairment and early Alzheimer's disease

Methods: A specific acetylcholinesterase tracer, [methyl-(11)C]N-methyl-piperidyl-4-acetate ([(11)C]MP4A), and a three dimensional PET system with magnetic resonance coregistration were used for imaging. Results: There was a significant difference in the acetylcholinesterase activity in the hippocampus between the groups (p = 0.03), the mean (SD) acetylcholinesterase activity (k(3) values, min(-1)) being 0.114 (0.036) in controls, 0.098 (0.023) in mild cognitive impairment, and 0.085 (0.022) in Alzheimer's disease. The mini-mental state examination score showed no significant relation with acetylcholinesterase activity in any brain area in the combined mild cognitive impairment/Alzheimer group. Conclusions: Hippocampal acetylcholinesterase activity is only slightly reduced in mild cognitive impairment and early Alzheimer's disease and so the value of in vivo acetylcholinesterase measurements in detecting the early Alzheimer process is limited

European Association of Nuclear Medicine guideline for brain perfusion SPECT using 99mTc-labelled radiopharmaceuticals

status: publishe

Achievements in Neuroimaging during the past 25 years

From the historical perspective, nuclear medicine contributions to brain imaging started in the 1950s with cerebral blood flow (CBF) measurements determined by the Kety- Schmidt method and inert radioactive gases. Inhalation methods with venous sampling initially allowed hemispheric CBF determination [1]. In the early 1960s, intra-arterial injection methods with externally placed scintillation detectors first demonstrated the possibility of performing regional CBF evaluation [2]. However, these methods were used more as research tools in physiology than for direct patient care. The same was true for the pioneering brain PET studies [3]. At the beginning of the 1980s, brain SPECT for perfusion studies became more amenable to clinical use. The first tomographic images were obtained with krypton-85 and a conventional gamma camera [4]. Even more encouraging, however, was the availability of dedicated tomographic cameras [5] and the first results using a stable radiopharmaceutical: 123I-IMP [6-8]. However, despite interesting results, neuroimaging was still considered to be a research tool due to the lack of more widely available radiopharmaceuticals. Many nuclear physicians were still "neurosceptics"! As stated at this time by Coleman et al. in their editorial in 1982, "the future of SPECT in studying regional brain function appeared very promising. A compound had to be developed that could be labelled with Tc-99m in a kit form" [9]

European Association of Nuclear Medicine procedure guidelines for brain neurotransmission SPECT using 123I-labelled dopamine transporter ligands

status: publishe

EANM guidelines for brain neurotransmission SPECT/PET using dopamine D2 receptor ligands

The guidelines summarize the current views of the European Association of Nuclear Medicine Neuroimaging Committee (ENC). The aims of the guidelines are to assist nuclear medicine practitioners in making recommendations, performing, interpreting and reporting the results of clinical dopamine D2 receptor SPECT or PET studies, and to achieve a high quality standard of dopamine D2 receptor imaging, which will increase the impact of this technique in neurological practice.The present document is an update of the first guidelines for SPECT using D2 receptor ligands labelled with (123)I [1] and was guided by the views of the Society of Nuclear Medicine Brain Imaging Council [2], and the individual experience of experts in European countries. The guidelines intend to present information specifically adapted to European practice. The information provided should be taken in the context of local conditions and regulations.status: publishe

EANM procedure guidelines for PET brain imaging using [(18)F]FDG

These guidelines summarize the current views of the European Association of Nuclear Medicine Neuroimaging Committee (ENC). The purpose of the guidelines is to assist nuclear medicine practitioners in making recommendations, performing, interpreting, and reporting the results of fluorine-18 fluoro-2-deoxyglucose ([(18)F]FDG) PET imaging of the brain. The aim is to help achieve a high standard of FDG imaging, which will increase the diagnostic impact of this technique in neurological and psychiatric practice. The present document replaces a former version of the guidelines that were published in 2002 [1] and includes an update in the light of advances in PET technology, the introduction of hybrid PET/CT systems and the broadening clinical indications for FDG brain imaging. These guidelines are intended to present information specifically adapted for European practice. The information provided should be taken in the context of local conditions and regulations.status: publishe