The authors of this paper have informed us that they have identified several methodological errors in this paper. The authors stress that the errors are primarily slight numerical alterations and do not alter any of the important outcomes or conclusions, or any of the points made in the discussion in the article. The changes to be made as a result of these errors are outlined in this corrigendum.
Overview of errors
The calculated cut-off values as shown are determined based on sensitivity and specificity instead of maximum positive predictive and negative predictive values. This is misleadingly written in the current version of the article. Correcting this would alter several sentences in the methods and in the result. Please see the Full list of corrections to be made for further details on the changes made.
The authors stress that the method originally followed to determine threshold values was not changed in this correction, but was rather incorrectly described under methods and materials in the original article. The authors felt therefore that additional clarity was required for reproducibility.
Further, a coding error was made in the receiver-operating characteristic curve calculation and generation, whereby sensitivity, specificity, positive and negative predictive values in the current version are the inverse from what they should be when using thresholds to diagnose tumour progression. This has led to a mirroring of Figure 4, and the corrected figure has been supplied in this corrigendum. The changes are again outlined under Full list of corrections to be made.
Also, several diagnostic metrics were incorrectly calculated and certain threshold values were not optimally derived for some of the PET measuring parameters. Please again see the Full list of corrections to be made for the corrected versions.
Lastly, a data handling error was made during the analysis whereby old values for T/Nmean, T/Nmax-mean, and T/Npeak-mean were inadvertently used for some analyses. The updated correct raw data have been added to Supplemental Table 1; Table 1, Supplemental Table 3 and Figure 3 have been correspondingly changed to reflect this update. These are minor changes that do not alter any findings. Please see the Full list of corrections to be made for more details, and please note that any page numbers specified refer to the PDF version of the article.
Full list of corrections to be made
1. On page 3 of 8, in the second paragraph under statistical analysis (part of methods and materials), the line:
SUVmean: 2.00 (sensitivity: 71.43%, specificity: 70.59%. positive predictive value: 74.97% and negative predictive value: 55.70%), should read: ‘2.00 (sensitivity: 70.59%, specificity: 71.43%, positive predictive value: 75.00% and negative predictive value: 66.67%)’.
SUVpeak: 2.45 (sensitivity: 78.57%, specificity: 70.59%. positive predictive value: 74.32% and negative predictive value: 75.25%), should read: ‘2.45 (sensitivity: 70.59%, specificity: 78.57%, positive predictive value: 80.00% and negative predictive value: 68.75%)’.
T/Nmax-mean: 2.03 (sensitivity: 71.43%, specificity: 70.59%. positive predictive value: 72.46% and negative predictive value: 69.52%), should read: ‘1.93 (sensitivity: 76.47%, specificity: 71.43%, positive predictive value: 76.47% and negative predictive value: 71.43%)’.
T/Nmean: 1.33 (sensitivity: 71.43%, specificity: 64.71%. positive predictive value: 68.68% and negative predictive value: 67.65%), should read: ‘1.33 (sensitivity: 64.71%, specificity: 71.43%, positive predictive value: 73.34% and negative predictive value: 62.50%)’.
T/Npeak-mean: 1.40 (sensitivity: 71.43%, specificity: 64.71%. positive predictive value: 70.56% and negative predictive value: 64.32%), should read: ‘1.49 (sensitivity: 64.71%, specificity: 71.43%, positive predictive value: 73.34% and negative predictive value: 62.50%)’.
TLMM: 6.45 (sensitivity: 64.29%, specificity: 64.71%. positive predictive value: 66.37% and negative predictive value: 62.58%), should read: ‘6.38 (sensitivity: 70.59%, specificity: 64.29%, positive predictive value: 70.59% and negative predictive value: 64.29%)’.
‘The receiver-operating-characteristic curve was used to define a threshold value by way of Youden’s index/J statistic for the diagnosis of TP corresponding to sensitivity and specificity values according to the PET measuring parameter. Positive and negative predictive values were then calculated. The diagnostic threshold was ultimately determined on the basis of maximum positive predictive and negative predictive values, which were considered more clinically relevant diagnostic guides’,
should read:
SUVmean: 2.00 (sensitivity: 71.43%, specificity: 70.59%. positive predictive value: 74.97% and negative predictive value: 55.70%), should read: ‘2.00 (sensitivity: 70.59%, specificity: 71.43%, positive predictive value: 75.00% and negative predictive value: 66.67%)’.
SUVpeak: 2.45 (sensitivity: 78.57%, specificity: 70.59%. positive predictive value: 74.32% and negative predictive value: 75.25%), should read: ‘2.45 (sensitivity: 70.59%, specificity: 78.57%, positive predictive value: 80.00% and negative predictive value: 68.75%)’.
T/Nmax-mean: 2.03 (sensitivity: 71.43%, specificity: 70.59%. positive predictive value: 72.46% and negative predictive value: 69.52%), should read: ‘1.93 (sensitivity: 76.47%, specificity: 71.43%, positive predictive value: 76.47% and negative predictive value: 71.43%)’.
T/Nmean: 1.33 (sensitivity: 71.43%, specificity: 64.71%. positive predictive value: 68.68% and negative predictive value: 67.65%), should read: ‘1.33 (sensitivity: 64.71%, specificity: 71.43%, positive predictive value: 73.34% and negative predictive value: 62.50%)’.
T/Npeak-mean: 1.40 (sensitivity: 71.43%, specificity: 64.71%. positive predictive value: 70.56% and negative predictive value: 64.32%), should read: ‘1.49 (sensitivity: 64.71%, specificity: 71.43%, positive predictive value: 73.34% and negative predictive value: 62.50%)’.
TLMM: 6.45 (sensitivity: 64.29%, specificity: 64.71%. positive predictive value: 66.37% and negative predictive value: 62.58%), should read: ‘6.38 (sensitivity: 70.59%, specificity: 64.29%, positive predictive value: 70.59% and negative predictive value: 64.29%)’.
‘The receiver-operating-characteristic curve was used to visualise threshold values by way of Youden’s index/J statistic for the diagnosis of TP corresponding to sensitivity and specificity values according to the PET measuring parameter. Positive and negative predictive values were then calculated. The diagnostic threshold was however ultimately determined on the basis of balancing the maximum trade-off between sensitivity and specificity, in which both were considered equally .’
On page 5 of 8, in the second paragraph under tests for diagnostic ability (part of results), the line:
SUVmean: 2.00 (sensitivity: 71.43%, specificity: 70.59%. positive predictive value: 74.97% and negative predictive value: 55.70%), should read: ‘2.00 (sensitivity: 70.59%, specificity: 71.43%, positive predictive value: 75.00% and negative predictive value: 66.67%)’.
SUVpeak: 2.45 (sensitivity: 78.57%, specificity: 70.59%. positive predictive value: 74.32% and negative predictive value: 75.25%), should read: ‘2.45 (sensitivity: 70.59%, specificity: 78.57%, positive predictive value: 80.00% and negative predictive value: 68.75%)’.
T/Nmax-mean: 2.03 (sensitivity: 71.43%, specificity: 70.59%. positive predictive value: 72.46% and negative predictive value: 69.52%), should read: ‘1.93 (sensitivity: 76.47%, specificity: 71.43%, positive predictive value: 76.47% and negative predictive value: 71.43%)’.
T/Nmean: 1.33 (sensitivity: 71.43%, specificity: 64.71%. positive predictive value: 68.68% and negative predictive value: 67.65%), should read: ‘1.33 (sensitivity: 64.71%, specificity: 71.43%, positive predictive value: 73.34% and negative predictive value: 62.50%)’.
T/Npeak-mean: 1.40 (sensitivity: 71.43%, specificity: 64.71%. positive predictive value: 70.56% and negative predictive value: 64.32%), should read: ‘1.49 (sensitivity: 64.71%, specificity: 71.43%, positive predictive value: 73.34% and negative predictive value: 62.50%)’.
TLMM: 6.45 (sensitivity: 64.29%, specificity: 64.71%. positive predictive value: 66.37% and negative predictive value: 62.58%), should read: ‘6.38 (sensitivity: 70.59%, specificity: 64.29%, positive predictive value: 70.59% and negative predictive value: 64.29%)’.
‘According to Youden’s index/J statistic by way of maximising both the positive and negative predictive values, the threshold value for the diagnosis of TP for SUVmax was 3.29 (sensitivity: 78.57%, specificity: 70.59%, positive predictive value: 74.32% and negative predictive value: 75.25%)’,
should read:
SUVmean: 2.00 (sensitivity: 71.43%, specificity: 70.59%. positive predictive value: 74.97% and negative predictive value: 55.70%), should read: ‘2.00 (sensitivity: 70.59%, specificity: 71.43%, positive predictive value: 75.00% and negative predictive value: 66.67%)’.
SUVpeak: 2.45 (sensitivity: 78.57%, specificity: 70.59%. positive predictive value: 74.32% and negative predictive value: 75.25%), should read: ‘2.45 (sensitivity: 70.59%, specificity: 78.57%, positive predictive value: 80.00% and negative predictive value: 68.75%)’.
T/Nmax-mean: 2.03 (sensitivity: 71.43%, specificity: 70.59%. positive predictive value: 72.46% and negative predictive value: 69.52%), should read: ‘1.93 (sensitivity: 76.47%, specificity: 71.43%, positive predictive value: 76.47% and negative predictive value: 71.43%)’.
T/Nmean: 1.33 (sensitivity: 71.43%, specificity: 64.71%. positive predictive value: 68.68% and negative predictive value: 67.65%), should read: ‘1.33 (sensitivity: 64.71%, specificity: 71.43%, positive predictive value: 73.34% and negative predictive value: 62.50%)’.
T/Npeak-mean: 1.40 (sensitivity: 71.43%, specificity: 64.71%. positive predictive value: 70.56% and negative predictive value: 64.32%), should read: ‘1.49 (sensitivity: 64.71%, specificity: 71.43%, positive predictive value: 73.34% and negative predictive value: 62.50%)’.
TLMM: 6.45 (sensitivity: 64.29%, specificity: 64.71%. positive predictive value: 66.37% and negative predictive value: 62.58%), should read: ‘6.38 (sensitivity: 70.59%, specificity: 64.29%, positive predictive value: 70.59% and negative predictive value: 64.29%)’.
‘ By way of equally balancing the maximum trade-off between sensitivity and specificity , the threshold value for the diagnosis of TP for SUVmax was 3.29 (sensitivity: 70.59%, specificity: 78.57%, positive predictive value: 80.00% and negative predictive value: 68.75% )’.
On page 5 of 8, in the second paragraph under tests for diagnostic ability (part of results), some of the remaining metrics for SUVmean, SUVpeak, T/Nmax-mean, T/Nmean, T/Npeak-mean and TLMM were incorrectly derived and should be changed as follows:
SUVmean: 2.00 (sensitivity: 71.43%, specificity: 70.59%. positive predictive value: 74.97% and negative predictive value: 55.70%), should read: ‘2.00 (sensitivity: 70.59%, specificity: 71.43%, positive predictive value: 75.00% and negative predictive value: 66.67%)’.
SUVpeak: 2.45 (sensitivity: 78.57%, specificity: 70.59%. positive predictive value: 74.32% and negative predictive value: 75.25%), should read: ‘2.45 (sensitivity: 70.59%, specificity: 78.57%, positive predictive value: 80.00% and negative predictive value: 68.75%)’.
T/Nmax-mean: 2.03 (sensitivity: 71.43%, specificity: 70.59%. positive predictive value: 72.46% and negative predictive value: 69.52%), should read: ‘1.93 (sensitivity: 76.47%, specificity: 71.43%, positive predictive value: 76.47% and negative predictive value: 71.43%)’.
T/Nmean: 1.33 (sensitivity: 71.43%, specificity: 64.71%. positive predictive value: 68.68% and negative predictive value: 67.65%), should read: ‘1.33 (sensitivity: 64.71%, specificity: 71.43%, positive predictive value: 73.34% and negative predictive value: 62.50%)’.
T/Npeak-mean: 1.40 (sensitivity: 71.43%, specificity: 64.71%. positive predictive value: 70.56% and negative predictive value: 64.32%), should read: ‘1.49 (sensitivity: 64.71%, specificity: 71.43%, positive predictive value: 73.34% and negative predictive value: 62.50%)’.
TLMM: 6.45 (sensitivity: 64.29%, specificity: 64.71%. positive predictive value: 66.37% and negative predictive value: 62.58%), should read: ‘6.38 (sensitivity: 70.59%, specificity: 64.29%, positive predictive value: 70.59% and negative predictive value: 64.29%)’.
In the abstract, the sensitivity, specificity, positive predictive and negative predictive values for SUVmax of 78.57%, 70.59%, 74.32 and 75.25%, should read 70.59%, 78.57%, 80.00 and 68.75% respectively.
Figure 4 has been mirrored to reflect the coding error whereby sensitivity, specificity, positive and negative predictive values in the current version are the inverse from what they should be when using thresholds to diagnose tumour progression (see corrected Figure 4 below).
In Supplemental Table 1 and 2, case-numbers 1, 10, 15 and 24 were incorrectly labelled as RIC in the original table. These have been corrected as cases of TP in both this file as well as Supplemental Table 2 (see attached corrected Supplemental Table 1 and 2).
The following changes below are because of the data handling error whereby outdated values for for T/Nmean, T/Nmax-mean, and T/Npeak-mean for case-numbers 5, 14, 16, 18, 19, 20, 22, 28 and 29 were inadvertently used for some analyses. The following changes are as a result of updating this raw data:
On page 4 of 8, in the second paragraph under PET measuring parameter comparison, the p-value for T/Nmean should be changed from p = 0.007 to p = 0.008 , the p-value for T/Nmax-mean should be changed from p = 0.006 to p = 0.008 and the p-value for T/Npeak-mean should be changed from p = 0.008 to p = 0.012 .
The raw data for T/Nmean, T/Nmax-mean and T/Npeak-mean for case-numbers 5, 14, 16, 18, 19, 20, 22, 28 and 29 have been appropriately updated in Supplemental Table 1 (see attached Supplemental Table 1).
Figure 3 has also been adjusted slightly to account for the changed values for T/Nmean, T/Nmax-mean, and T/Npeak-mean (see corrected Figure 3 below) and the changed significance value for T/Npeak-mean from p = 0.008 to p = 0.012 (*p < 0.05 instead of **p < 0.01).
The analysis by camera-type has been adjusted slightly to account for the changed values for T/Nmean, T/Nmax-mean, and T/Npeak-mean (see attached Supplemental Table 3). The results of this analysis in terms of statistical significance remain unaltered.
In Table 1 on page 4, the interquartile ranges for T/Nmean, T/Nmax-mean and T/Npeak-mean have been corrected for both the radiation-induced changes (RIC) and tumour progression (TP) groups. In addition, the exponent for T/Npeak-mean has been changed from b to a, representing a recalculated significance value for the Mann-Whitney U test from p = 0.008 to p = 0.012 . These changes alter Table 1 from:
| Definitive diagnosis | SUVmean b | SUVmax b | SUVpeak b | T/Nmean b | T/Nmax-mean b | T/Npeak-mean b | TLMM a | MTV |
|---|---|---|---|---|---|---|---|---|
| RIC (N = 14) | 1.79 (1.46–2.13) | 2.66 (2.26–3.25) | 2.11 (1.74–2.44) | 1.09 (0.87–1.33) | 1.71 (1.41–2.18) | 1.33 (1.08–1.49) | 4.63 (2.43–6.65) | 2.59 (1.61–3.62) |
| TP (N=17) | 2.63 (1.84–3.53) | 4.35 (2.89–5.86) | 3.27 (2.17–4.07) | 1.55 (1.19–2.23) | 2.58 (1.89–3.73) | 1.88 (1.41–2.46) | 7.37 (4.90–10.72) | 2.47 (2.05–3.54) |
Table. MET-PET measuring parameter quantitative comparison
Median and IQR (Q1-Q3) for each MET-PET measuring parameter according to the definitive diagnosis. RIC: radiation-induced changes; TP: tumour progression; SUV: standardised-uptake value; T/N: tumour-to-normal tissue ratio; TLMM: total-lesion methionine metabolism; MTV: metabolic-tumour-volume.
ap <0.05, bp <0.01 (Mann-Whitney U test).
To as follows (see next page):
| Definitive diagnosis | SUVmean b | SUVmax b | SUVpeak b | T/Nmean b | T/Nmax-mean b | T/Npeak-mean a | TLMM a | MTV |
|---|---|---|---|---|---|---|---|---|
| RIC (N = 14) | 1.79 (1.46–2.13) | 2.66 (2.26–3.25) | 2.11 (1.74–2.44) | 1.09 (0.91–1.39) | 1.71 (1.42–2.25) | 1.33 (1.12–1.57) | 4.63 (2.43–6.65) | 2.59 (1.61–3.62) |
| TP (N = 17) | 2.63 (1.84–3.53) | 4.35 (2.89–5.86) | 3.27 (2.17–4.07) | 1.55 (1.21–2.43) | 2.58 (1.92–4.07) | 1.88 (1.41–2.68) | 7.37 (4.90–10.72) | 2.47 (2.05–3.54) |
Table. MET-PET measuring parameter quantitative comparison
Median and IQR (Q1-Q3) for each MET-PET measuring parameter according to the definitive diagnosis. RIC: radiation-induced changes; TP: tumour progression; SUV: standardised-uptake value; T/N: tumour-to-normal tissue ratio; TLMM: total-lesion methionine metabolism; MTV: metabolic-tumour-volume.
ap <0.05, bp <0.01 (Mann-Whitney U test).
These changes have been made to the online version of the paper. The authors and the BIR apologise for the errors.