Observer variation in interpreting 18F-FDG PET/CT findings for lymphoma staging.

UNLABELLED: Many studies demonstrate a high accuracy for PET in staging lymphoma, but few assess observer variation. This study quantified agreement for staging lymphoma with PET/CT. METHODS: The PET/CT images of 100 patients with lymphoma who had been referred for staging were reviewed by 3 experienced observers, with 2 observers reviewing each series a second time. Ann Arbor stage and individual nodal and extranodal regions were assessed. Weighted kappa (kappa(w)) and intraclass correlation coefficient were used to compare ratings. RESULTS: Intra- and interobserver agreement was high for Ann Arbor stage (kappa(w) = 0.79-0.91), number of nodal regions involved (intraclass correlation coefficient, 0.83-0.93), and presence of extranodal disease (kappa = 0.74-0.86). High agreement was also observed for all nodal regions (kappa(w) > 0.60) except hilar (kappa(w) = 0.56-0.82) and infraclavicular (kappa(w) = 0.14-0.55). Lower agreement was observed for bowel involvement (kappa(w) = 0.37-0.71). CONCLUSION: Experienced observers had a high level of agreement using PET/CT for lymphoma staging, supporting its use as a robust noninvasive staging tool. Further research is needed to evaluate observer variability for restaging during and after chemotherapy.

Observer variation in FDG PET-CT for staging of non-small-cell lung carcinoma.

PURPOSE: Error and variation in reporting remains one of the weakest features of clinical imaging despite enormous technological advances in nuclear medicine and radiology. The aim of this study was to evaluate agreement amongst experienced readers in staging non-small-cell lung cancer (NSCLC) with PET-CT. METHODS: A series of (18)F-FDG PET-CT scans from 100 consecutive patients were reviewed independently by three experienced readers, with two readers reviewing each scan series a second time. Individual mediastinal lymph node stations were assessed as benign/inflammatory, equivocal or malignant, and AJCC N and M stage were also assigned. Kappa (kappa) was used to compare ratings from two categories and weighted kappa (kappa(w)) for three or more categories, and kappa values were interpreted according to the Landis-Koch benchmarks. RESULTS: Both intra- and interobserver agreement for N and M staging were high. For M staging there was almost perfect intra- and interobserver agreement (kappa = 0.90-0.93). For N staging, agreement was either almost perfect or substantial (intraobserver kappa(w) = 0.79, 0.91; interobserver kappa(w) = 0.75-0.81). Importantly, there was almost perfect agreement for N0/1 vs N2/3 disease (kappa = 0.80-0.97). Agreement for inferior and superior mediastinal nodes (stations 1, 2, 3, 7, 8, 9) was either almost perfect or substantial (kappa(w) = 0.71-0.88), but lower for hilar nodes (10; kappa(w) = 0.56-0.71). Interreporter variability was greatest for aortopulmonary nodes (5, 6; kappa(w) = 0.48-0.55). CONCLUSION: Amongst experienced reporters in a single centre, there was a very high level of agreement for both mediastinal nodal stage and detection of distant metastases with PET-CT. This supports the use of PET-CT as a robust imaging modality for staging NSCLC.

The prognostic value of interim positron emission tomography scans combined with immunohistochemical data in diffuse large B-cell lymphoma.

The treatment of hematologic malignancies is moving towards risk-stratified directed therapy, whereby treatment is based on the disease's biological characteristics and response to treatment. We investigated whether BCL2 and BCL6 status could add to the prognostic information yielded by an interim positron emission tomography (PET) scan in the ability to predict outcome. Negative interim scans and BCL2-negative status correlated with continuing remission (p<0.005) at a median follow up of 24 months.