Use of Standardized Uptake Value Ratios Decreases Interreader Variability of [18F] Florbetapir PET Brain Scan Interpretation

Nayate, Ameya; Dubroff, Jacob; Schmitt, J. Eric; Nasrallah, Ilya M.; Kishore, Rajiv; Mankoff, David A.; Pryma, Daniel A.

doi:10.3174/ajnr.a4281

Cited by 44 publications

(39 citation statements)

References 38 publications

(68 reference statements)

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“…These data support our hypothesis that augmenting visual interpretation of amyloid-β PET scans of cognitively normal participants with quantitative information decreased the variability of rater interpretations, which is consistent with other recent studies utilizing a similar Visual Read only technique (Kappa 0.40–0.89) [6, 8–10, 12–13, 17–18]. Our results also suggest that the addition of quantitative PET scan data is most important for the improved detection of early plaque deposition or in cases where the patient demonstrates borderline Visual or Quantitative Reads (e.g., 1–2 qualitative and/or quantitative positive ROIs).…”

Section: Discussionsupporting

confidence: 92%

Augmenting Amyloid PET Interpretations With Quantitative Information Improves Consistency of Early Amyloid Detection

Harn

Hunt²,

Hill³

et al. 2017

Clinical Nuclear Medicine

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Purpose Establishing reliable methods for interpreting elevated cerebral amyloid-β plaque on PET scans is increasingly important for radiologists, as availability of PET imaging in clinical practice increases. We examined a three-step method to detect plaque in cognitively normal older adults, focusing on the additive value of quantitative information during the PET scan interpretation process. Methods Fifty-five F-18 florbetapir PET scans were evaluated by three experienced raters. Scans were first visually interpreted as having “elevated” or “non-elevated” plaque burden (“Visual Read”). Images were then processed using a standardized quantitative analysis software (MIMneuro) to generate whole brain and region of interest (ROI) standard uptake value ratios (SUVRs). This “Quantitative Read” was considered elevated if at least two of six ROIs had an SUVR >1.1. The final interpretation combined both visual and quantitative data together (“VisQ Read”). Cohen’s kappa values were assessed as a measure of interpretation agreement. Results Plaque was elevated in 25.5–29.1% of the 165 total Visual Reads. Inter-rater agreement was strong (Kappa=0.73–0.82) and consistent with reported values. Quantitative Reads were elevated in 45.5% of participants. Final VisQ Reads changed from initial Visual Reads in 16 (9.7%) interpretations, with most changing from “non-elevated” Visual Reads to “elevated.” These changed interpretations demonstrated lower plaque quantification than those initially read as “elevated” that remained unchanged. Inter-rater variability improved for VisQ Reads with the addition of quantitative information (Kappa=0.88–0.96). Conclusion Inclusion of quantitative information increases consistency of PET scan interpretations for early detection of cerebral amyloid-β plaque accumulation.

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Section: Discussionsupporting

confidence: 92%

Augmenting Amyloid PET Interpretations With Quantitative Information Improves Consistency of Early Amyloid Detection

Harn

Hunt²,

Hill³

et al. 2017

Clinical Nuclear Medicine

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“…The reported gain of visual read accuracy by taking SUVrs into consideration is also in accordance with the fact that visual read and SUVr results might differ within at least some amyloid PET cases [17][18][19]. Also in accordance with the Pontecorvo et al data, it was recently shown that taking SUVrs into account decreases inter-reader variability of amyloid PET diagnosis [20]. It would be useful to better understand in the present study the discordance between visual and quantitative assessments, and in what settings this occurred.…”

supporting

confidence: 73%

Yes we can analyse amyloid images - Now What?

Barthel

Seibyl

Sabri

2017

Eur J Nucl Med Mol Imaging

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# Springer-Verlag Berlin Heidelberg 2017 With the recent introduction of amyloid PET tracers into clinical use, non-invasive biomarker information on brain amyloidosis is available which challenges the long-accepted gold standard of post mortem histopathology for diagnosing Alzheimer's disease (AD). Phase 3 amyloid PET studies in end of life patients with post mortem verification of brain amyloid status have arguably shifted the time-point of diagnosing amyloid pathology to ante mortem. Florbetapir, florbetaben, and flutemetamol, the PET tracers utilised for that purpose, share high sensitivity/specificity in detecting/ excluding beta-amyloid aggregates which accumulate in the neocortex of AD brains [1][2][3]. Further, comparably high discrimination accuracy was reported for these tracers between patients with clinical diagnosis of AD dementia and healthy controls [4,5]. The main advantages of these tracers are the high image signal associated with these Bhot spot^imaging tracers and the binary nature of the PET result when applied in certain scenarios (reproducible mild cognitive impairment, early-onset AD dementia, Bpossible^AD dementia according to clinical testing [6,7]). This is because, in line with the amyloid cascade theory of AD [8], amyloid pathology should be full-blown by the time cognitive decline manifests. This favourable scenario motivated the regulatory authorities to approve these tracers based solely on a visual PET assessment by readers who have passed a tracer-specific training.Respective training programs utilised for that purpose describe a series of rules referent to the question of whether there is grey vs. white matter contrast. In parallel to these efforts to establish read algorithms, in the USA the IDEAS study [9] is underway, aimed at providing outcome data about the clinical relevance of amyloid PET crucial for future reimbursement. In Europe, this effort will soon be followed by the AMYPAD study [10]. Besides the use of amyloid PET for primary diagnosis of brain amyloid pathology in conjunction with AD, the above tracers are intensively utilized in drug testing trials [11] for confirming eligibility and monitoring the impact of therapy on brain amyloidosis.Yet, like any diagnostic test, PET amyloid visual assessments are not perfect and technical and biological factors pose challenges to accurate scan interpretation, particularly for the inexperienced reader. Further, some concerns have been raised in the past on the validity of visual read rules [12] which might result in relevant inter-reader variability [13]. One principle advantage of the PET imaging technique lies in its quantitative nature. The question of how important quantitative data are in cases of amyloid PET image analysis depends on the question to be addressed by the PET procedure. There is no doubt that in cases where amyloid imaging is used for follow-up evaluation/therapy monitoring quantitation is important. In this instance quantitative methods using dynamic imaging and kinetic modelling should ideally be p...

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“…In spite of these potential issues, only one study to date has evaluated the performance of quantitative software as an adjunct to visual interpretation. Specifically, Nayate et al [21] recently reported that the use of Siemens Scenium software to quantitate florbetapir PET scans significantly increased interreader reliability. Although an increase in interreader reliability is encouraging, it does not necessarily mean that there has been an increase in reader accuracy.…”

Section: Introductionmentioning

confidence: 99%

Quantitation of PET signal as an adjunct to visual interpretation of florbetapir imaging

Pontecorvo

Arora

Devine

et al. 2017

Eur J Nucl Med Mol Imaging

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Purpose This study examined the feasibility of using quantitation to augment interpretation of florbetapir PET amyloid imaging. Methods A total of 80 physician readers were trained on quantitation of florbetapir PET images and the principles for using quantitation to augment a visual read. On day 1, the readers completed a visual read of 96 scans (46 autopsy-verified and 50 from patients seeking a diagnosis). On day 2, 69 of the readers reinterpreted the 96 scans augmenting their interpretation with quantitation (VisQ method) using one of three commercial software packages. A subset of 11 readers reinterpreted all scans on day 2 based on a visual read only (VisVis control). For the autopsy-verified scans, the neuropathologist's modified CERAD plaque score was used as the truth standard for interpretation accuracy. Because an autopsy truth standard was not available for scans from patients seeking a diagnosis, the majority VisQ interpretation of the three readers with the best accuracy in interpreting autopsy-verified scans was used as the reference standard. Results Day 1 visual read accuracy was high for both the autopsy-verified scans (90%) and the scans from patients seeking a diagnosis (87.3%). Accuracy improved from the visual read to the VisQ read (from 90.1% to 93.1%, p < 0.0001).Importantly, access to quantitative information did not decrease interpretation accuracy of the above-average readers (>90% on day 1). Accuracy in interpreting the autopsy-verified scans also increased from the first to the second visual read (VisVis group). However, agreement with the reference standard (best readers) for scans from patients seeking a diagnosis did not improve with a second visual read, and in this cohort the VisQ group was significantly improved relative to the VisVis group (change 5.4% vs. −1.1%, p < 0.0001). Conclusion These results indicate that augmentation of visual interpretation of florbetapir PET amyloid images with quantitative information obtained using commercially available software packages did not reduce the accuracy of readers who were already performing with above average accuracy on the visual read and may improve the accuracy and confidence of some readers in clinically relevant cases.

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Use of Standardized Uptake Value Ratios Decreases Interreader Variability of [18F] Florbetapir PET Brain Scan Interpretation

Cited by 44 publications

References 38 publications

Augmenting Amyloid PET Interpretations With Quantitative Information Improves Consistency of Early Amyloid Detection

Augmenting Amyloid PET Interpretations With Quantitative Information Improves Consistency of Early Amyloid Detection

Yes we can analyse amyloid images - Now What?

Quantitation of PET signal as an adjunct to visual interpretation of florbetapir imaging

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