Evaluation of age-related changes in translocator protein (TSPO) in human brain using \u3csup\u3e11\u3c/sup\u3eC-[R]-PK11195 PET

Abstract Background We studied the distribution and expression of translocator protein in the human brain using 11C-[R]-PK-11195 positron emission tomography (PK11195 PET) and evaluated age-related changes. Methods A dynamic PK11195 PET scan was performed in 15 normal healthy adults (mean age: 29 ±8.5 years (range: 20 to 49); 7 males) and 10 children (mean age: 8.8 ±5.2 years (range: 1.2 to 17); 5 males), who were studied for potential neuroinflammation but showed no focally increased PK11195 binding. The PET images were evaluated by calculating standard uptake values and regional binding potential, based on a simplified reference region model, as well as with a voxel-wise analysis using statistical parametric mapping. Results PK11195 uptake in the brain is relatively low, compared with the subcortical structures, and symmetrical. The overall pattern of PK11195 distribution in the brain does not change with age. PK11195 uptake was lowest in the frontal-parietal-temporal cortex and highest in the pituitary gland, midbrain, thalamus, basal ganglia, occipital cortex, hippocampus and cerebellum, in descending order. White matter showed negligible PK11195 uptake. Overall, brain PK11195 uptake increased with age, with midbrain and thalamus showing relatively higher increases with age compared with other brain regions. Conclusions The brain shows low PK11195 uptake, which is lower in the cortex and cerebellum compared with subcortical structures, suggesting a low level of translocator protein expression. There is no hemispheric asymmetry in PK11195 uptake and the overall pattern of PK11195 distribution in the brain does not change with age. However, brain PK11195 uptake increases with age, with the thalamus and midbrain showing relatively higher increases compared with other brain regions. This increase in uptake suggests an age-related increase in translocator protein expression or the number of cells expressing these receptors or both

Evaluation of age-related changes in translocator protein (TSPO) in human brain using ¹¹C-[R]-PK11195 PET

Abstract Background We studied the distribution and expression of translocator protein in the human brain using 11C-[R]-PK-11195 positron emission tomography (PK11195 PET) and evaluated age-related changes. Methods A dynamic PK11195 PET scan was performed in 15 normal healthy adults (mean age: 29 ±8.5 years (range: 20 to 49); 7 males) and 10 children (mean age: 8.8 ±5.2 years (range: 1.2 to 17); 5 males), who were studied for potential neuroinflammation but showed no focally increased PK11195 binding. The PET images were evaluated by calculating standard uptake values and regional binding potential, based on a simplified reference region model, as well as with a voxel-wise analysis using statistical parametric mapping. Results PK11195 uptake in the brain is relatively low, compared with the subcortical structures, and symmetrical. The overall pattern of PK11195 distribution in the brain does not change with age. PK11195 uptake was lowest in the frontal-parietal-temporal cortex and highest in the pituitary gland, midbrain, thalamus, basal ganglia, occipital cortex, hippocampus and cerebellum, in descending order. White matter showed negligible PK11195 uptake. Overall, brain PK11195 uptake increased with age, with midbrain and thalamus showing relatively higher increases with age compared with other brain regions. Conclusions The brain shows low PK11195 uptake, which is lower in the cortex and cerebellum compared with subcortical structures, suggesting a low level of translocator protein expression. There is no hemispheric asymmetry in PK11195 uptake and the overall pattern of PK11195 distribution in the brain does not change with age. However, brain PK11195 uptake increases with age, with the thalamus and midbrain showing relatively higher increases compared with other brain regions. This increase in uptake suggests an age-related increase in translocator protein expression or the number of cells expressing these receptors or both.</p

Abstract 036: Diagnostic Accuracy of IONM for Perioperative Strokes during Endovascular Treatment of Ruptured Intracranial Aneurysms

Introduction Ruptured aneurysmal SAH accounts up to 80% of nontraumatic SAH, with more than 80% located in the anterior circulation and a mortality rate upwards of 50%.1‐3 Endovascular treatment (EVT) of ruptured intracranial aneurysms (rIA) is increasingly being recognized as a standard treatment that may result in better early outcomes and independency when compared with open neurosurgical clipping in cases of appropriate equipoise.1,2,4–6 Despite this, EVT of intracranial aneurysms has its own risk of complications including intraoperative rupture and thromboembolic events.7 The complication rate is found to be higher in cases of rIA than that seen in cases of unruptured intracranial aneurysms.8 The use of somatosensory evoked potentials (SSEP) and electroencephalography (EEG) intraoperative neuromonitoring (IONM) have proven their efficacy in identifying iatrogenic neurological complications in vascular surgeries including carotid endarterectomy 9–11, EVT and microsurgical treatment of intracranial aneurysms. 11,12 rIA have their own unique challenges due to preoperative neurological deficits and perioperative vasospasm making it more difficult to identify new neurological deficits after the procedure. They are also associated with decreased vasoreactivity secondary to bleeding, and a higher rate of procedural complications that can alter the IONM signals.13,14 IONM in the form of SSEP and EEG can be utilized in anesthetized patients to indirectly monitor intraoperative cerebral perfusion as well as central and peripheral neuronal integrity.15,16 Changes in one or both modalities indicate a change in cerebral perfusion that can be related to EVT directly, for example, aneurysm perforation or coil herniation and embolism, or indirectly secondary to anesthesia and hemodynamic changes.17 (Figure1) Methods We reviewed the medical records of 323 patients who underwent EVT of ruptured aneurysms with IONM utilizing SSEP and EEG. We included all patients who had endovascular management of ruptured aneurysm and completed IONM records until the end of the procedure and excluded those with no IONM records or incomplete records. Patients were divided into 2 groups, one group with postprocedural neurological deficits (PPND) and one group without PPND. Results Total of 323 patients undergoing EVT, significant IONM changes were noted in 71 patients (21.98%) and 46 (14.24%) who experienced PPND. 22 out of 71 (30.98%) patients who had significant IONM changes experienced PPND. Univariable analysis demonstrated that persistent changes in SSEP and EEG were associated with PPND (p‐values: <0.001 and <0.001). Multivariable analysis showed that persistent IONM changes were significantly associated with PPND (OR: 8.28 (95%CI:2.92‐24.66, p‐value: <0.001). Simultaneous changes in both modalities had a specificity of 95% (95% CI: 0.92, 0.97%) and sensitivity of 48% (95% CI: 0.33, 0.63) to predict PPND when either modality had a change. Out of 46 patients with PPND, 29 (63.04%) experienced periprocedural complications. PPND was associated with periprocedural complications with a p‐value <0.001. Also, multivariable analysis showed an association between IONM changes and persistent IONM changes with PPND with OR of 7.35 (95% CI; 3.68, 15.03) and 7.25 (95% CI; 3.58, 15.00), respectively. Conclusion Significant IONM changes during EVT for rIA are associated with an increased risk of PPND