Diagnostic Accuracy of Virtual 18F-FDG PET/CT Bronchoscopy for the Detection of Lymph Node Metastases in Non–Small Cell Lung Cancer Patients

Revolutionizing lymph node metastasis imaging: the role of drug delivery systems and future perspectives

The deployment of imaging examinations has evolved into a robust approach for the diagnosis of lymph node metastasis (LNM). The advancement of technology, coupled with the introduction of innovative imaging drugs, has led to the incorporation of an increasingly diverse array of imaging techniques into clinical practice. Nonetheless, conventional methods of administering imaging agents persist in presenting certain drawbacks and side effects. The employment of controlled drug delivery systems (DDSs) as a conduit for transporting imaging agents offers a promising solution to ameliorate these limitations intrinsic to metastatic lymph node (LN) imaging, thereby augmenting diagnostic precision. Within the scope of this review, we elucidate the historical context of LN imaging and encapsulate the frequently employed DDSs in conjunction with a variety of imaging techniques, specifically for metastatic LN imaging. Moreover, we engage in a discourse on the conceptualization and practical application of fusing diagnosis and treatment by employing DDSs. Finally, we venture into prospective applications of DDSs in the realm of LNM imaging and share our perspective on the potential trajectory of DDS development.

Outcome of patients with negative and unsatisfactory cytologic specimens obtained by endobronchial ultrasound-guided transbronchial fine-needle aspiration of mediastinal lymph nodes

BACKGROUND

Endobronchial ultrasound-guided transbronchial fine-needle aspiration (EBUS-FNA) has gained acceptance as the diagnostic procedure of choice with which to sample hilar and mediastinal lymph nodes (LNs) for diagnosing and staging patients with lung cancer. Studies have shown that EBUS has a high positive predictive value; however, its negative predictive value (NPV) varies significantly. The aim of the current study was to evaluate the clinical outcome surrounding negative and nondiagnostic EBUS-FNA of mediastinal LNs.

METHODS

A retrospective chart review of cases of EBUS-FNA performed between 2008 and the middle of 2011 was conducted. Mediastinal LNs with cytologic diagnoses of negative for malignant cells and unsatisfactory were selected for the study. Each LN was followed for up to 1 year with imaging or biopsy/surgical resection. A true-negative result was defined as a LN that did not enlarge on repeat imaging or was negative for malignancy on repeat biopsy or surgery during the follow-up period.

RESULTS

Among 1418 LNs sampled, 479 from 228 patients met the search criteria, including 394 LN (82.3%) with the cytologic diagnosis of negative for malignant cells and 85 (17.8%) with a diagnosis of unsatisfactory. A total of 104 patients (45.6%) were followed with imaging, and 124 patients (54.3%) underwent repeat biopsy/surgery. A total of 445 LNs met the definition of a true-negative finding, resulting in an overall NPV of 92.9% (95% confidence interval [95% CI], 90.6%-95.2%). The NPVs of a negative and unsatisfactory diagnosis were 93.9% (95% CI, 91.6%-96.3%) and 88.2% (95% CI, 81.4%-95.1%), respectively.

CONCLUSIONS

The vast majority of LNs with a cytologic diagnosis of negative and unsatisfactory were likely to be true-negative findings. In these patients, a more conservative approach to follow-up may be appropriate.

Accuracy of diffusion-weighted (DW) MRI with background signal suppression (MR-DWIBS) in diagnosis of mediastinal lymph node metastasis of nonsmall-cell lung cancer (NSCLC)

PURPOSE

To prospectively evaluate the accuracy of diffusion-weighted (DW) magnetic resonance (MR) imaging with background signal suppression (MR-DWIBS) for detecting mediastinal lymph node metastasis of nonsmall-cell lung cancer (NSCLC).

MATERIALS AND METHODS

MR-DWIBS was performed in 42 consecutive patients (27 men, 15 women; age range, 42-78 years; median age, 55 years) with histologically proven NSCLC. The visualization rate of metastatic lymph node (MLN) and benign lymph node (BLN) of enlarged lymph nodes (ELN) and normal-sized lymph nodes (NLN) was compared by using a chi-square test or Fisher's exact test on a per-nodal basis. Apparent diffusion coefficient (ADC) of MLN and BLN was measured and compared by using two-tailed unpaired Student's t-test. Receiver operating characteristic (ROC) analysis was used to assess the overall diagnostic accuracy of ADC for ELN and NLN. The optimal cutoff value was determined and the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy was calculated.

RESULTS

Thirty-five out of 119 lymph resected nodes were confirmed to be metastatic by histologic examination. The visualization rate of MLN was significantly higher than that of BLN for ELN (P < 0.001) and for NLN (χ(2) = 7.506, P = 0.006). For both ELN and NLN, ADC of MLN was significantly lower than that of BLN (t = -5.380, P < 0.001 and t = -6.435, P < 0.001). ADC was significant for detection of MLN for both ELN (Az = 0.975, P < 0.001) and NLN (Az = 0.919, P < 0.001). For NLN, the optimal cutoff value of ADC was 2.04 mm(2)/s, where the sensitivity, specificity, PPV, NPV, and accuracy were 75.0%, 90.9%, 66.7%, 93.8%, and 87.8%, respectively.

CONCLUSION

MR-DWIBS may be clinically useful to visually detect mediastinal lymph nodes and ADC measurement can aid in malignant node discrimination.

Virtual 18F-FDG PET/CT bronchoscopy for lymph node staging in non-small-cell lung cancer patients: present and future applications

Virtual (18)F-fluorodeoxyglucose (FDG) PET/computed tomography (CT) bronchoscopies provide virtually realistic, 3D endoscopic views of the airways combining anatomical and functional data at a high resolution. Today, even very small airways can be imaged by virtual bronchoscopy. (18)F-FDG PET/CT bronchoscopy images are generated from standard whole-body (18)F-FDG PET/CT scan source data without any additional radiation exposure. The purpose of this review was to give an overview over the studies that are currently available, to provide the technical background of (18)F-FDG PET/CT bronchoscopy and to explain the diagnostic accuracy of (18)F-FDG PET/CT bronchoscopy. Moreover, this manuscript highlights potential future applications of this promising new imaging technique.