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Background: Diffuse large B‐cell lymphoma (DLBCL) is the most common form of lymphoma. European guidelines recommend FDG‐PET/CT for staging and end of treatment (EOT) response assessment, mid‐treatment response assessment is optional. We compared the Lugano classification and PET Response Criteria In Solid Tumours (PERCIST) for FDG‐PET/CT response assessment in DLBCL head‐to‐head. Methods: We retrospectively included patients with DLBCL who underwent first‐line R‐CHOP(‐like) therapy (2013−2020). Interim and EOT FDG‐PET/CT response were reevaluated using the Lugano classification and PERCIST. Response was dichotomized into complete metabolic response (CMR) versus non‐CMR (interim and EOT) and responders versus nonresponders (interim only). The cutoff for nonresponse at interim was a Deauville score of 5 (DS5) with the Lugano classification and a partial metabolic response with ≤66% reduction in SULpeak using PERCIST (PERCIST66). Results: In multivariable Cox regression (N = 170), DS5 at interim, PERCIST66 at interim, non‐CMR at EOT with the Lugano classification and non‐CMR at EOT with PERCIST were predictive of progression‐free survival (PFS). The Lugano classification and PERCIST agreed perfectly at interim and EOT and with 98.4% for the identification of nonresponders at interim. The accuracy for predicting events within 2 years of diagnosis was 84.2% for DS‐5 at interim, 87.6% for PERCIST66 at interim, 86% for non‐CMR with the Lugano classification at EOT and 83.3% for non‐CMR with PERCIST at EOT. Conclusion: The Lugano classification and PERCIST were equally predictive of PFS. Nonresponse at interim and non‐CMR at EOT were predictive of poor PFS with comparable accuracy for predicting events within 2 years. [ABSTRACT FROM AUTHOR]

Method comparison studies comprised simple scatterplots of paired measurements, a 45-degree line as benchmark, and correlation coefficients up to the advent of Bland–Altman analysis in the 1980s. The Agatston score for coronary calcification is based on computed tomography of the heart, and it originated in 1990. A peculiarity of the Agatston score is the often-observed skewed distribution in screening populations. As the Agatston score has manifested itself in preventive cardiology, it is of interest to investigate how reproducibility of the Agatston score has been established. This review is based on literature findings indexed in MEDLINE/PubMed before 20 November 2021. Out of 503 identified articles, 49 papers were included in this review. Sample sizes were highly variable (10–9761), the main focus comprised intra- and interrater as well as intra- and interscanner variability assessments. Simple analysis tools such as scatterplots and correlation coefficients were successively supplemented by first difference, later Bland–Altman plots; however, only very few publications were capable of deriving Limits of Agreement that fit the observed data visually in a convincing way. Moreover, several attempts have been made in the recent past to improve the analysis and reporting of method comparison studies. These warrant increased attention in the future. [ABSTRACT FROM AUTHOR]

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Summary: Aim: To test the feasibility of a fully automated artificial intelligence‐based method providing PET measures of prostate cancer (PCa). Methods: A convolutional neural network (CNN) was trained for automated measurements in 18F‐choline (FCH) PET/CT scans obtained prior to radical prostatectomy (RP) in 45 patients with newly diagnosed PCa. Automated values were obtained for prostate volume, maximal standardized uptake value (SUVmax), mean standardized uptake value of voxels considered abnormal (SUVmean) and volume of abnormal voxels (Volabn). The product SUVmean × Volabn was calculated to reflect total lesion uptake (TLU). Corresponding manual measurements were performed. CNN‐estimated data were compared with the weighted surgically removed tissue specimens and manually derived data and related to clinical parameters assuming that 1 g ≈ 1 ml of tissue. Results: The mean (range) weight of the prostate specimens was 44 g (20–109), while CNN‐estimated volume was 62 ml (31–108) with a mean difference of 13·5 g or ml (95% CI: 9·78–17·32). The two measures were significantly correlated (r = 0·77, P<0·001). Mean differences (95% CI) between CNN‐based and manually derived PET measures of SUVmax, SUVmean, Volabn (ml) and TLU were 0·37 (−0·01 to 0·75), −0·08 (−0·30 to 0·14), 1·40 (−2·26 to 5·06) and 9·61 (−3·95 to 23·17), respectively. PET findings Volabn and TLU correlated with PSA (P<0·05), but not with Gleason score or stage. Conclusion: Automated CNN segmentation provided in seconds volume and simple PET measures similar to manually derived ones. Further studies on automated CNN segmentation with newer tracers such as radiolabelled prostate‐specific membrane antigen are warranted. [ABSTRACT FROM AUTHOR]

Background: Group-sequential testing is widely used in pivotal therapeutic, but rarely in diagnostic research, although it may save studies, time, and costs. The purpose of this paper was to demonstrate a group-sequential analysis strategy in an intra-observer study on quantitative FDG-PET/CT measurements, illuminating the possibility of early trial termination which implicates significant potential time and resource savings. Methods: Primary lesion maximum standardised uptake value (SUVmax) was determined twice from preoperative FDG-PET/CTs in 45 ovarian cancer patients. Differences in SUVmax were assumed to be normally distributed, and sequential one-sided hypothesis tests on the population standard deviation of the differences against a hypothesised value of 1.5 were performed, employing an alpha spending function. The fixed-sample analysis ( N = 45) was compared with the group-sequential analysis strategies comprising one (at N = 23), two (at N = 15, 30), or three interim analyses (at N = 11, 23, 34), respectively, which were defined post hoc. Results: When performing interim analyses with one third and two thirds of patients, sufficient agreement could be concluded after the first interim analysis and the final analysis. Other partitions did not suggest early stopping after adjustment for multiple testing due to one influential outlier and our small sample size. Conclusions: Group-sequential testing may enable early stopping of a trial, allowing for potential time and resource savings. The testing strategy must, though, be defined at the planning stage, and sample sizes must be reasonably large at interim analysis to ensure robustness against single outliers. Group-sequential testing may have a place in accuracy and agreement studies. [ABSTRACT FROM AUTHOR]

Measurement procedures are not error-free. Potential users of a measurement procedure need to know the expected magnitude of the measurement error in order to justify its use, in particular in health care settings. Gold standard procedures providing exact measurements for comparisons are often lacking. Consequently, scientific investigations of the measurement error are often based on using replicates. However, a standardized terminology (and partially also methodology) for such investigations is lacking. In this paper, we explain the basic conceptual approach of such investigations with minimal reference to existing terminology and describe the link to the existing general statistical methodology. This way, some of the key measures used in such investigations can be explained in a simple manner and some light can be shed on existing terminology. We encourage clearly conceptually distinguishing between investigations of the measurement error of a single measurement procedure and the comparison between different measurement procedures or observers. We also identify an unused potential for more advanced statistical analyses in scientific investigations of the measurement error. [ABSTRACT FROM AUTHOR]

The Bland–Altman plot is the most common method to analyze and visualize agreement between raters or methods of quantitative outcomes in health research. While very useful for studies with two raters, a limitation of the classical Bland–Altman plot is that it is specifically used for studies with two raters. We propose an extension of the Bland–Altman plot suitable for more than two raters and derive the approximate limits of agreement with 95 % confidence intervals. We validated the suggested limit of agreement by a simulation study. Moreover, we offer suggestions on how to present bias, heterogeneity among raters, as well as the uncertainty of the limits of agreement. The resulting plot could be utilized to investigate and present agreement in studies with more than two raters. [ABSTRACT FROM AUTHOR]

The purpose was to investigate the interrater agreement of FDG-PET/CT and bone scintigraphy for diagnosing bone recurrence in breast cancer patients. A total of 100 women with suspected recurrence of breast cancer underwent planar whole-body bone scintigraphy with [99mTc]DPD and FDG-PET/CT. Scans were evaluated independently by experienced nuclear medicine physicians and the results for one modality were blinded to the other. Images were visually interpreted using a 4-point assessment scale (0 = no metastases, 1 = probably no metastases, 2 = probably metastases, 3 = definite metastases). Out of 100 women, 22 (22%) were verified with distant recurrence, 18 of these had bone involvement. The proportions of agreement between readers were 93% (86.3–96.6) for bone recurrence with FDG-PET/CT and 47% (37.5–56.7) for bone recurrence with planar bone scintigraphy. The strengths of agreement between readers for diagnosing bone recurrence was 'almost perfect' with FDG-PET/CT and was 'fair' with planar bone scintigraphy according to Cohen's kappa value of 0.82 (0.70–0.95) and 0.28 (0.18–0.39), respectively. Interrater agreement yielded improved reproducibility with FDG-PET/CT versus with bone scintigraphy when diagnosing recurrence with bone metastasis in this patient cohort. [ABSTRACT FROM AUTHOR]

Response evaluation at regular intervals is indicated for treatment of metastatic breast cancer (MBC). FDG-PET/CT has the potential to monitor treatment response accurately. Our purpose was to: (a) compare the interrater agreement and reliability of the semi-quantitative PERCIST criteria to qualitative visual assessment in response evaluation of MBC and (b) investigate the intrarater agreement when comparing visual assessment of each rater to their respective PERCIST assessment. We performed a retrospective study on FDG-PET/CT in women who received treatment for MBC. Three specialists in nuclear medicine categorized response evaluation by qualitative assessment and standardized one-lesion PERCIST assessment. The scans were categorized into complete metabolic response, partial metabolic response, stable metabolic disease, and progressive metabolic disease. 37 patients with 179 scans were included. Visual assessment categorization yielded moderate agreement with an overall proportion of agreement (PoA) between raters of 0.52 (95% CI 0.44–0.66) and a Fleiss kappa estimate of 0.54 (95% CI 0.46–0.62). PERCIST response categorization yielded substantial agreement with an overall PoA of 0.65 (95% CI 0.57–0.73) and a Fleiss kappa estimate of 0.68 (95% CI 0.60–0.75). The difference in PoA between overall estimates for PERCIST and visual assessment was 0.13 (95% CI 0.06–0.21; p = 0.001), that of kappa was 0.14 (95% CI 0.06–0.21; p < 0.001). The overall intrarater PoA was 0.80 (95% CI 0.75–0.84) with substantial agreement by a Fleiss kappa of 0.74 (95% CI 0.69–0.79). Semi-quantitative PERCIST assessment achieved significantly higher level of overall agreement and reliability compared with qualitative assessment among three raters. The achieved high levels of intrarater agreement indicated no obvious conflicting elements between the two methods. PERCIST assessment may, therefore, give more consistent interpretations between raters when using FDG-PET/CT for response evaluation in MBC. [ABSTRACT FROM AUTHOR]

The Bland–Altman Limits of Agreement is a popular and widespread means of analyzing the agreement of two methods, instruments, or raters in quantitative outcomes. An agreement analysis could be reported as a stand-alone research article but it is more often conducted as a minor quality assurance project in a subgroup of patients, as a part of a larger diagnostic accuracy study, clinical trial, or epidemiological survey. Consequently, such an analysis is often limited to brief descriptions in the main report. Therefore, in several medical fields, it has been recommended to report specific items related to the Bland–Altman analysis. The present study aimed to identify the most comprehensive and appropriate list of items for such an analysis. Seven proposals were identified from a MEDLINE/PubMed search, three of which were derived by reviewing anesthesia journals. Broad consensus was seen for the a priori establishment of acceptability benchmarks, estimation of repeatability of measurements, description of the data structure, visual assessment of the normality and homogeneity assumption, and plotting and numerically reporting both bias and the Bland–Altman Limits of Agreement, including respective 95% confidence intervals. Abu-Arafeh et al. provided the most comprehensive and prudent list, identifying 13 key items for reporting (Br. J. Anaesth. 2016, 117, 569–575). An exemplification with interrater data from a local study accentuated the straightforwardness of transparent reporting of the Bland–Altman analysis. The 13 key items should be applied by researchers, journal editors, and reviewers in the future, to increase the quality of reporting Bland–Altman agreement analyses. [ABSTRACT FROM AUTHOR]

The Guidelines for Reporting Reliability and Agreement Studies (GRRAS) were proposed in 2011 to support transparent and accurate reporting. These studies may be conducted with the primary aim of estimating reliability and/or agreement itself, but are more often than not part of larger diagnostic accuracy studies, clinical trials, or epidemiological studies. As such, the study design may be compromised in terms of practicability issues, preventing the collection of sufficient results. We presented an example from a consultancy with a difficult mission and discussed five questions that concern the very nature of such a study (agreement vs. reliability; intra- vs. interrater), the rater population, explanatory factors in a multivariable model, and the statistical analysis strategy. Discussion of such basic methodological and statistical questions must take place before an investigation is started in order to ensure adequate data collection, to predict possible complications in the study, to plan sufficient statistical analyses, and to request timely assistance from an experienced statistician. GRRAS and its accompanying checklist of 15 items proved to be most helpful. Hopefully, our commentary will help improve the planning of agreement and reliability studies, which, in turn, will then be more focused, more appropriate, and more easily reported using GRRAS. [ABSTRACT FROM AUTHOR]