Ryuichi Nishii MD, PhD, Presenter: Nothing to Disclose

Hiroshi Mizuma PhD, Abstract Co-Author: Nothing to Disclose

Shinya Kagawa, Abstract Co-Author: Nothing to Disclose

Tatsuya Higashi MD, Abstract Co-Author: Nothing to Disclose

Hiroshi Yamauchi MD, PhD, Abstract Co-Author: Nothing to Disclose

Youichi Mizutani, Abstract Co-Author: Nothing to Disclose

Shigeki Nagamachi MD, PhD, Abstract Co-Author: Nothing to Disclose

Hirotaka Onoe PhD, Abstract Co-Author: Nothing to Disclose

2-[18F]Fluoroacetate (FACE) has been considered as a PET probe for evaluating glial metabolism (Marik et al., JNM, 2009), though little is known about its detailed functions in cerebral ischemia. We here examined changes in brain uptake of [18F]FACE by PET during cerebral ischemia, in combination with immunohistochemistry study for confirming glial cell activation associated with neuroinflammation.

Rats were occluded in the right middle cerebral artery for 60 min, and were reperfused, subsequently (tMCAO). [18F]FACE-PET scan for 60 min under isoflurane anesthesia was conducted at 2 hr (early phase) and 7th day (later phase) after reperfusion. Glial activation was assessed by both [11C]PK11195-PET imaging for translocator protein (TSPO) and immunohistochemical staining with anti-CD11b and anti-GFAP antibodies for activated microglia and reactive astrocyte, respectively. Cerebral infarction was measured by 2,3,5-triphenyltetrazolium chloride (TTC) staining after PET imaging.

[18F]FACE uptake in the lesion side at 2 hr after reperfusion was significantly high compared with that in the contralateral side (p<0.05), whereas such an increase in uptake in the lesion side was very low at 7th day. In contrast, [11C]PK11195 binding markedly elevated only at 7th day but not at 2 hr, concomitantly with microglia and astrocyte activation. Besides, the cerebral infarction observed in 7th day after reperfusion was not detected at 2 hr.

These finding indicate that [18F]FACE-PET imaging could visualize the preinfarct area without any glial activation associated with neuroinflammation.

[18F]FACE uptake at early stage of cerebral ischemia might be tightly associated with emergent metabolic shift coupled with neural dysfunction.

Nishii, R, Mizuma, H, Kagawa, S, Higashi, T, Yamauchi, H, Mizutani, Y, Nagamachi, S, Onoe, H, Increased Uptake of 2-[18F]fluoroacetate at Early Phase of Cerebral Ischemia.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14018254.html