Comparison of manual and semi-automated delineation of regions of interest for radioligand PET imaging analysis

BACKGROUND As imaging centers produce higher resolution research scans, the number of man-hours required to process regional data has become a major concern. Comparison of automated vs. manual methodology has not been reported for functional imaging. We explored validation of using automation to delineate regions of interest on positron emission tomography (PET) scans. The purpose of this study was to ascertain improvements in image processing time and reproducibility of a semi-automated brain region extraction (SABRE) method over manual delineation of regions of interest (ROIs). METHODS We compared 2 sets of partial volume corrected serotonin 1a receptor binding potentials (BPs) resulting from manual vs. semi-automated methods. BPs were obtained from subjects meeting consensus criteria for frontotemporal degeneration and from age- and gender-matched healthy controls. Two trained raters provided each set of data to conduct comparisons of inter-rater mean image processing time, rank order of BPs for 9 PET scans, intra- and inter-rater intraclass correlation coefficients (ICC), repeatability coefficients (RC), percentages of the average parameter value (RM%), and effect sizes of either method. RESULTS SABRE saved approximately 3 hours of processing time per PET subject over manual delineation (p 0.8) for both methods. RC and RM% were lower for the manual method across all ROIs, indicating less intra-rater variance across PET subjects' BPs. CONCLUSION SABRE demonstrated significant time savings and no significant difference in reproducibility over manual methods, justifying the use of SABRE in serotonin 1a receptor radioligand PET imaging analysis. This implies that semi-automated ROI delineation is a valid methodology for future PET imaging analysis

Neuropsychiatric symptoms as a sign of small vessel disease progression in cognitive impairment

BACKGROUND: Neuropsychiatric symptoms associate cross-sectionally with cerebral small vessel disease but it is not clear whether these symptoms could act as early clinical markers of small vessel disease progression. We investigated whether longitudinal change in Neuropsychiatric Inventory (NPI) scores associated with white matter hyperintensity (WMH) progression in a memory clinic population. MATERIAL AND METHODS: We included participants from the prospective Sunnybrook Dementia Study with Alzheimer's disease and vascular subtypes of mild cognitive impairment and dementia with two MRI and ≥ 1 NPI. We conducted linear mixed-effects analyses, adjusting for age, atrophy, vascular risk factors, cognition, function, and interscan interval. RESULTS: At baseline (n=124), greater atrophy, age, vascular risk factors and total NPI score were associated with higher baseline WMH volume, while longitudinally, all but vascular risk factors were associated. Change in total NPI score was associated with change in WMH volume, χ2 = 7.18, p = 0.007, whereby a one-point change in NPI score from baseline to follow-up was associated with a 0.0017 change in normalized WMH volume [expressed as cube root of (WMH volume cm³ as % intracranial volume)], after adjusting for age, atrophy, vascular risk factors and interscan interval. CONCLUSIONS: In memory clinic patients, WMH progression over 1–2 years associated with worsening neuropsychiatric symptoms, while WMH volume remained unchanged in those with stable NPI scores in this population with low background WMH burden

Random Matrix Model for Superconductors in a Magnetic Field

We introduce a random matrix ensemble for bulk type-II superconductors in the mixed state and determine the single-particle excitation spectrum using random matrix theory. The results are compared with planar tunnel junction experiments in PbBi thin films. More low energy states appear than in the Abrikosov-Gor'kov-Maki or Ginzburg-Landau descriptions, consistent with observations.Comment: 4 pages, 1 postscript figure, to appear in Phys. Rev. Let

The Canadian Dementia Imaging Protocol: Harmonization validity for morphometry measurements

© 2019 The Authors The harmonized Canadian Dementia Imaging Protocol (CDIP) has been developed to suit the needs of a number of co-occurring Canadian studies collecting data on brain changes across adulthood and neurodegeneration. In this study, we verify the impact of CDIP parameters compliance on total brain volume variance using 86 scans of the same individual acquired on various scanners. Data included planned data collection acquired within the Consortium pour l\u27identification précoce de la maladie Alzheimer - Québec (CIMA-Q) and Canadian Consortium on Neurodegeneration in Aging (CCNA) studies, as well as opportunistic data collection from various protocols. For images acquired from Philips scanners, lower variance in brain volumes were observed when the stated CDIP resolution was set. For images acquired from GE scanners, lower variance in brain volumes were noticed when TE/TR values were within 5% of the CDIP protocol, compared to values farther from that criteria. Together, these results suggest that a harmonized protocol like the CDIP may help to reduce neuromorphometric measurement variability in multi-centric studies

Surgical anatomy of the lower eyelid relating to lower blepharoplasty

The aim of this review is to familiarize the reader with the critical lower eyelid anatomy as is related to lower blepharoplasty or a midface lift. The contents include 1) the lacrimal canaliculus in the lower eyelid: the depth and width (diameter) of the vertical portion were 2.58±0.24 mm and 0.44±0.07 mm, respectively. A vertical portion of the canaliculus was about 1 mm (1.11±0.16 mm) deep, and the horizontal portion was about 2~3 mm (2.08±2.74 mm) long 2 mm below the mucocutaneous junction, which is where an incision may be made when performing epicanthoplasty. 2) Motor innervation to the lower orbiculis oculi muscle: the pretarsal and preseptal OOMs were innervated by five to seven terminal twigs of the zygomatic branches of the facial nerve that approached the muscle at a right angle. The mean horizontal distance between the lateral canthus and the zygomatic branch was 2.31±0.29 cm (range: 1.7~2.7 cm) and the vertical distance was 1.20±0.20 cm (range: 0.8~1.5 cm). 3) Sensory innervation of the lower eyelid skin: the majority of the terminal branches (93.8%) of the ION were distributed to the medial to the lateral canthus. Most (99.4%) of the terminal branches of the ZFN were distributed to lateral to the lateral canthus. 4) Retractor of the lower eyelid; capsulopalpebral fascia (CPF): the orbital septum blended with the CPF most closely at 3.7~5.4 mm beneath the lower tarsal border and differently at 3.7±0.7 mm on the medial limbus line, 4.3±0.8 mm on the midpupillary line and 5.4±1.0 mm on the lateral limbus line. 5) Arcuate expansion (AE): The AE was a fibrous band expanding from the inferolateral orbital rim to the medial canthal ligament. A sector (fan-shaped) of the AE originated in the angle of 5 to 80 degrees at the circumference of the inferolateral orbital rim circle, falling within the range of 3 to 5.5 o'clock, and then it tapered and attached to the inferior border of the medial canthal ligament. 6) Suborbicularis oculi fat (SOOF) in the lower eyelid: the SOOF was located in the inferolateral side of the orbit within a range between medial +15 and lateral -89 degrees to a vertical midpupillary line. Histologically, the SOOF was situated deep to the Orbicularis oculi muscle and superficial to the orbital septum and periosteum. The SOOF consisted more of fibrofatty tissue rather than being the pure fatty nature like orbital fat. I hope surgeons can achieve desirable outcomes with the knowledge reviewed in this article

Comparison of quality control methods for automated diffusion tensor imaging analysis pipelines

© 2019 Haddad et al. The processing of brain diffusion tensor imaging (DTI) data for large cohort studies requires fully automatic pipelines to perform quality control (QC) and artifact/outlier removal procedures on the raw DTI data prior to calculation of diffusion parameters. In this study, three automatic DTI processing pipelines, each complying with the general ENIGMA framework, were designed by uniquely combining multiple image processing software tools. Different QC procedures based on the RESTORE algorithm, the DTIPrep protocol, and a combination of both methods were compared using simulated ground truth and artifact containing DTI datasets modeling eddy current induced distortions, various levels of motion artifacts, and thermal noise. Variability was also examined in 20 DTI datasets acquired in subjects with vascular cognitive impairment (VCI) from the multi-site Ontario Neurodegenerative Disease Research Initiative (ONDRI). The mean fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) were calculated in global brain grey matter (GM) and white matter (WM) regions. For the simulated DTI datasets, the measure used to evaluate the performance of the pipelines was the normalized difference between the mean DTI metrics measured in GM and WM regions and the corresponding ground truth DTI value. The performance of the proposed pipelines was very similar, particularly in FA measurements. However, the pipeline based on the RESTORE algorithm was the most accurate when analyzing the artifact containing DTI datasets. The pipeline that combined the DTIPrep protocol and the RESTORE algorithm produced the lowest standard deviation in FA measurements in normal appearing WM across subjects. We concluded that this pipeline was the most robust and is preferred for automated analysis of multisite brain DTI data