PIB PET scans were performed at CUMC Kreitchman PET Center (n=45) on an ECAT EXACT HR+ (Siemens, Knoxville, TN) or Weill Cornell Medicine Citigroup Biomedical Imaging Center (n=32) on a Siemens Biograph mCT. Immediately following 30-second intravenous PIB injection, dynamic images were acquired in 3D mode at 3 × 20 sec, 3 × 1 min, 3 × 2 min, 2 × 5 min, and 7 × 10 min. Low-dose CT scan was performed for attenuation correction. A 3D SPGR T1 Sequence was performed on a GE Signa 3 Tesla MRI scanner. PET scans were performed within one year of UPSIT (mean interval = 93.9 ± 93.1 days), with the exception of one subject who had PET scan performed 16.5 months after UPSIT.
PET analysis was performed using PMOD 3.6. MR images were segmented using the PNEURO tool and the Hammers-N30R83–1MM atlas was used to define regions-of-interest (ROIs). ROIs were inspected and manually corrected if necessary. PET images 50–70 min post-injection were averaged, co-registered to the corresponding MR image, and individual subject ROIs were then applied. Mean uptake over 50–70 min from a composite gray matter ROI from frontal, parietal, and lateral temporal cortex (excluding sensorimotor cortex) was divided by mean uptake in cerebellar gray matter to create a global standardized uptake value ratio (SUVR). PIB SUVR > 1.5 was used to define amyloid-β positivity [22 (link), 23 (link)].
PET analysis was performed using PMOD 3.6. MR images were segmented using the PNEURO tool and the Hammers-N30R83–1MM atlas was used to define regions-of-interest (ROIs). ROIs were inspected and manually corrected if necessary. PET images 50–70 min post-injection were averaged, co-registered to the corresponding MR image, and individual subject ROIs were then applied. Mean uptake over 50–70 min from a composite gray matter ROI from frontal, parietal, and lateral temporal cortex (excluding sensorimotor cortex) was divided by mean uptake in cerebellar gray matter to create a global standardized uptake value ratio (SUVR). PIB SUVR > 1.5 was used to define amyloid-β positivity [22 (link), 23 (link)].