Lung Nodule Management

An Interventional Pulmonology Perspective

Udit Chaddha, MBBS; Jonathan S. Kurman, MD, MBA; Amit Mahajan, MD, FCCP; D. Kyle Hogarth, MD

Disclosures

Semin Respir Crit Care Med. 2018;39(6):661-666. 

In This Article

Electromagnetic Navigation

ACCP guidelines recommend using EMN bronchoscopy to biopsy lung nodules that are difficult to reach with conventional bronchoscopy (Grade 1C).[22] The two commercially available EMN systems in the United States are superDimension (Medtronic, Minneapolis, MN) and SPiNView (Veran Medical Technologies, St. Louis, MO). TTNA and biopsies are possible through the SPiNPerc system (Veran Medical Technologies, St. Louis, MO) that consists of the same computer unit used with the SPiNView system, but with the addition of a needle that uses a stylet as its locatable sensor.

In 2006, the first feasibility study for the superDimension EMN system was published. The authors obtained positive biopsies in 9 of 13 patients, with an average navigation accuracy of 5.7 mm.[32] The first large-scale prospective study on 54 lung lesions resulted in a diagnostic yield of 74%.[33] The system consists of the iLogic VB planning software, an EWC, and a locatable guide (LG). The patient lays on a location board that creates a low-frequency electromagnetic field. The system can precisely track the position and orientation of the LG in a 3D reconstruction of the airway map created by reformatting data from a recent CT scan of the chest. Once the EWC is advanced to the target lesion, the LG is removed and biopsy instruments are passed through the EWC. Real-time confirmation of position can be aided by means of fluoroscopy and r-EBUS. Navigation should be readjusted if the desired r-EBUS view is not obtained.[10] One of the theoretical advantages of EMN compared to r-EBUS alone is that it allows for aligning instrumentation directly to a target lesion. However, the technology and the available biopsy tools limit the diagnostic yield when a bronchus sign is absent on the CT.[34]

In 2016, a pilot study was published using the Veran Medical EMN system that combined guided bronchoscopy with TTNA. While the yield for navigational bronchoscopy was only 33%, TTNA had a yield of 83%. However, 5 out of the 24 subjects developed a pneumothorax.[35] In contrast to the superDimension system, the Veran system uses both inspiratory and expiratory CT scans to account for nodule movement during respiration. The biopsy instruments are directly tracked allowing for real-time tissue sampling, eliminating the need for a separate LG.

EMN bronchoscopy is a safe modality with reported pneumothorax rates of approximately 3%.[36] To date there have been several studies published on the use of ENM to guide biopsies of peripheral lung lesions, with most reporting diagnostic yields between 67 and 84%, with similar results between the superDimension and Veran Medical systems.[37] ENM technologies have evolved through the years to improve navigation to smaller and more difficult to reach targets. An interim analysis of the ongoing multicenter NAVIGATE study reported navigational success in 94.4% of the cases.[38] Unfortunately, factors like respiratory motion,[39] CT-to-body divergence, and suboptimal diagnostic tools are major factors serving as challenges to attaining high diagnostic yields. EMN trials have demonstrated a higher yield in upper and middle lobe lesions, larger target size, lower average fiducial target registration error, a bronchus sign, use of r-EBUS, and sampling using suctioning.[36,40] Yet, overall diagnostic yields are still not superior to the transthoracic approach.

The newest version of the SuperDimension system uses a software algorithm that uses a 3D fluoroscopic navigation technology that helps to improve visualization of the lesion on fluoroscopy and accommodates to some degree for CT-to-body divergence caused by respiratory motion.

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