Page 86 - 18F-FDG PET as biomarker in aggressive lymphoma; technical and clinical validation
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Chapter 4
For ordinal DSs, the reviewers agreed in 214 of 465 cases (Supplemental Table 1), resulting in 46% exact agreement (95%CI, 41.4–50.7). Percentage agreement was 78.3% (95%CI, 74.4–82.1) when we allowed a 1-point difference—except for a discrepancy between scores 3 and 4—between the reviewers’ scorings.
Table 2 presents the percentage OA for the specific nodal and extranodal localizations for dichotomized DS, related to the baseline prevalence. Gastrointestinal, Waldeyer’s ring, skeletal, spleen, and mesenteric sites showed a relatively large number of discrepancies. An example of a discrepancy in the interim assessment of a mesenteric bulky lesion is shown in Figure 1.
Table 2. Interobserver agreement on specific nodal and extranodal localizations on I-PET.
Location
Number baseline positive
Number of discrepancies on I-PET
Agreement on negativity (absolute)
Agreement on positivity (absolute)
Percentage OA
Related to baseline prevalence
Nodal
Paraaortic* 414 17 Cervical*† 302 8 Iliac* 272 6 Supraclavicular* 228 6 Axillary* 225 9 Mediastinal† 212 12 Inguinal* 210 3 Mesenteric 189 16 Hilar*† 147 7 Spleen† 115 11 Other 105 7 Waldeyer† 53 8 Extranodal
Other extranodal† 124 17
Skeletal† 95 12
Gastrointestinal† 61 12
Lung† 55 3
Liver 37 3
Pleura 25 1
Skin 11 0
Central nervous 0 0 system
*Right and left are summed and presented together.
†Totals not 465 or 930, because of missing values or localization
Percentage OA = (number of agreement on positivity + number of agreement on negativity) / (number of discrepancies + number of agreement on positivity + number of agreement on negativity) x 100%; related to baseline prevalence = (number of discrepancies/number baseline positive) x 100%.
899 14 915 6 917 7 920 4 920 1 445 6 926 1 433 16 918 3 442 6 457 1 456 0
436 8 447 4 441 7 455 6 461 1 464 0 465 0 465 0
98.2 4.1% 99.1 2.6% 99.4 2.2% 99.4 2.6% 99.0 4.0% 97.4 5.7% 99.7 1.4% 96.6 8.5% 99.2 4.8% 97.6 9.6% 98.5 6.7% 98.3 15.1%
96.3 13.7% 97.4 12.6% 97.4 16.7% 99.4 5.5% 99.4 8.1% 99.8 4.0% 100.0 0.0% 100.0 0.0%
84
scored as unclear.
