Johan Lilja1, Lennart Thurfjell2, Jens Sörensen3. 1. GE Healthcare, Uppsala, Sweden Nuclear Medicine and PET, Department of Surgical Sciences, Uppsala University, Uppsala, Sweden; and johan.lilja@radiol.uu.se. 2. GE Healthcare, Uppsala, Sweden Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden. 3. Nuclear Medicine and PET, Department of Surgical Sciences, Uppsala University, Uppsala, Sweden; and.
Abstract
UNLABELLED: Three-dimensional stereotactic surface projection (3D-SSP) is a widely used method for the analysis of clinical (18)F-FDG brain studies. However, for PET amyloid scans the use of 3D-SSP is challenging because of nonspecific uptake in white matter. Our objective was to implement a method for 3D-SSP quantification and visualization of (18)F-flutemetamol images that avoids extraction of white matter signal. METHODS: Triangulated brain surface models were extracted from a T1-weighted MR template image. Using an (18)F-flutemetamol-negative template, a maximum depth for each vertex on the surface models was calculated to avoid extraction of white matter. The method was evaluated using (18)F-flutemetamol images from 2 cohorts. Cohort 1 consisted of 105 healthy volunteers and was used to create a normal database for each reference region. Cohort 2 consisted of 171 subjects including patients with Alzheimer disease and mild cognitive impairment and healthy volunteers. Images were spatially normalized using an adaptive template registration method, and SUV ratio 3D-SSP values were computed using the pons and cerebellar cortex as reference regions. Images from cohort 2 were then compared with the normal database and classified into negatives and positives, based on a calculated z score threshold. The results were compared with consensus visual interpretation results from 5 trained interpreters blinded to clinical data. RESULTS: With the pons as the reference region, the optimal z score threshold was 1.97, resulting in an overall agreement with visual interpretation results in 170 of 171 images (99.42%). With the cerebellar cortex as the reference region, the optimal z score threshold was 2.41, with an overall agreement with visual interpretation in 168 of 171 images (98.25%). CONCLUSION: Variable-depth 3D-SSP allows computation and visualization of (18)F-flutemetamol 3D-SSP maps, with minimized contribution from white matter signal while retaining sensitivity in detecting gray matter signal.
UNLABELLED: Three-dimensional stereotactic surface projection (3D-SSP) is a widely used method for the analysis of clinical (18)F-FDG brain studies. However, for PET amyloid scans the use of 3D-SSP is challenging because of nonspecific uptake in white matter. Our objective was to implement a method for 3D-SSP quantification and visualization of (18)F-flutemetamol images that avoids extraction of white matter signal. METHODS: Triangulated brain surface models were extracted from a T1-weighted MR template image. Using an (18)F-flutemetamol-negative template, a maximum depth for each vertex on the surface models was calculated to avoid extraction of white matter. The method was evaluated using (18)F-flutemetamol images from 2 cohorts. Cohort 1 consisted of 105 healthy volunteers and was used to create a normal database for each reference region. Cohort 2 consisted of 171 subjects including patients with Alzheimer disease and mild cognitive impairment and healthy volunteers. Images were spatially normalized using an adaptive template registration method, and SUV ratio 3D-SSP values were computed using the pons and cerebellar cortex as reference regions. Images from cohort 2 were then compared with the normal database and classified into negatives and positives, based on a calculated z score threshold. The results were compared with consensus visual interpretation results from 5 trained interpreters blinded to clinical data. RESULTS: With the pons as the reference region, the optimal z score threshold was 1.97, resulting in an overall agreement with visual interpretation results in 170 of 171 images (99.42%). With the cerebellar cortex as the reference region, the optimal z score threshold was 2.41, with an overall agreement with visual interpretation in 168 of 171 images (98.25%). CONCLUSION: Variable-depth 3D-SSP allows computation and visualization of (18)F-flutemetamol 3D-SSP maps, with minimized contribution from white matter signal while retaining sensitivity in detecting gray matter signal.
Authors: Natasha M Smith; Jeremy N Ford; Arsalan Haghdel; Lidia Glodzik; Yi Li; Debra D'Angelo; Arindam RoyChoudhury; Xiuyuan Wang; Kaj Blennow; Mony J de Leon; Jana Ivanidze Journal: Front Aging Neurosci Date: 2022-04-25 Impact factor: 5.702
Authors: David Fällmar; Johan Lilja; Torsten Danfors; Lena Kilander; Victor Iyer; Mark Lubberink; Elna-Marie Larsson; Jens Sörensen Journal: Am J Nucl Med Mol Imaging Date: 2018-08-20
Authors: Hugh G Pemberton; Lyduine E Collij; Fiona Heeman; Ariane Bollack; Mahnaz Shekari; Gemma Salvadó; Isadora Lopes Alves; David Vallez Garcia; Mark Battle; Christopher Buckley; Andrew W Stephens; Santiago Bullich; Valentina Garibotto; Frederik Barkhof; Juan Domingo Gispert; Gill Farrar Journal: Eur J Nucl Med Mol Imaging Date: 2022-04-07 Impact factor: 10.057