Prediction of lymph node metastases in NSCLC. Three dimensional anatomical parameters do not substitute FDG-PET-CT.
OBJECTIVE
To distinguish between benign and malignant mediastinal lymph nodes in patients with NSCLC by comparing 2D and semi-automated 3D measurements in FDG-PET-CT.


METHODS
FDG-PET-CT was performed in 46 patients prior to therapy. 299 mediastinal lymph-nodes were evaluated independently by two radiologists, both manually and by semi-automatic segmentation software. Longest-axial-diameter (LAD), shortest-axial-diameter (SAD), maximal-3D-diameter, elongation and volume were obtained. FDG-PET-CT and clinical/FDG-PET-CT follow up examinations and/or histology served as the reference standard. Statistical analysis encompassed intra-class-correlation-coefficients and receiver-operator-characteristics-curves (ROC).


RESULTS
The standard of reference revealed involvement in 87 (29%) of 299 lymph nodes. Manually and semi-automatically measured 2D parameters (LAD and SAD) showed a good correlation with mean intraclass coefficients of .80 and .72, respectively. Semi-automated prediction revealed the highest areas-under-the-ROC-curve for volume (.75, 95%CI: .69-81) and SAD (.75, 95%CI: .70-.81). AUC for LAD and maximal-3D diameter were about .68. Substantially lower accuracies were found for elongation (.57, 95%CI: .50-.64).


CONCLUSIONS
Optimized semi-automated three dimensional parameters by CT cannot approximate reported data on FDG-PET-CT for lymph node assessment in NSCLC. SAD remains the most accurate and at the same time simple to achieve anatomical criterion for definition of NSCLC target lesions.
Beyer
F
F
Department of Clinical Radiology, University of Muenster, Albert-Schweitzer-Strasse 33, 48129 Muenster, Germany.
Buerke
B
B
Gerss
J
J
Scheffe
K
K
Puesken
M
M
Weckesser
M
M
Schober
O
O
Heindel
W
W
Wessling
J
J
D000368:Aged; D001331:Automation; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging* / Q000473:pathology; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology; D008198:Lymph Nodes / Q000000981:diagnostic imaging / Q000473:pathology; D008207:Lymphatic Metastasis / Q000000981:diagnostic imaging* / Q000473:pathology; D008875:Middle Aged; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D012372:ROC Curve; D011859:Radiography; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
D019788:Fluorodeoxyglucose F18