Added value of 18F-FDG-PET/CT in addition to fiberoptic bronchoscopy in differentiation of solitary pulmonary nodules

Objectives To evaluate the diagnostic performance of 18F-FDG-PET/CT (PET) combined with fiberoptic bronchoscopy (FOB) compared to the single techniques in solitary pulmonary nodule (SPN) differentiation.

Methods We retrospectively evaluated 35 consecutive patients presenting with SPN (1-3 cm) identified by CT scans who underwent both PET and FOB for lesion differentiation. FOB included Trans-Bronchial Pulmonary Biopsy (TBB), Trans-Bronchial Pulmonary Needle Aspiration (TBNA) and bronchial washing (BW). Findings were considered positive as follows: PET, when SUVmax of FDG uptake in the lesion was ≥ 2.5; FOB, in case either TBB, TBNA or BW was positive for malignancy; PET and FOB combined, when at least one was positive. Results were confirmed through histology after surgery or follow-up, as reference standard. Sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) of PET, FOB and the 2 techniques combined were respectively calculated.

Results Out of the 35 patients PET, FOB and the combined procedures respectively resulted true positive (TP) in 28, 15 and 29 cases, true negative (TN) in 5, 6 and 5, false positive (FP) in 1, 0 and 1, false negative (FN) in 1, 14 and 0. PET was FP in 1 TN FOB case (inflammatory lesion), and FN in 1 TP FOB case (bronchioloalveolar carcinoma). FOB was FN in 14 TP PET cases. The diagnostic performance of PET, FOB and the combined procedures respectively resulted in: sensitivity 96.6, 51.7 and 100.0 %; specificity 83.3, 100.0 and 83.3 %; accuracy 94.3, 60.0 and 97.1 %; PPV 96.6, 100.0 and 96.7 %; NPV 83.3, 30.0 and 100.0 %.

Conclusions PET showed high sensitivity and accuracy playing an important diagnostic role especially in cases of FN FOB. The addition of PET to FOB resulted in an improved diagnostic accuracy that may lead to a better selection of patients with SPN addressed to surgery, and strengthens the value of multimodal patient management.