Toward the Guidance of Transbronchial Biopsy

Abstract

Background: Solitary pulmonary nodules (SPNs) frequently require transbronchial needle aspiration (TBNA) or biopsy to determine malignant potential, but have variable diagnostic yields. Confi rming needle placement within SPNs during TBNA could signifi cantly increase diagnostic yield. Optical coherence tomography (OCT) provides nondestructive, high-resolution, microstructural imaging with potential to distinguish SPN from parenchyma. We have developed needle-based OCT probes compatible with TBNA. Before OCT can play any signifi cant role in guiding clinical TBNA, OCT interpretation criteria for differentiating SPN from lung parenchyma must be developed and validated. Methods: OCT of SPN and parenchyma was performed on 111 ex vivo resection specimens. OCT criteria for parenchyma and SPN were developed and validated in a blinded assessment. Six blinded readers (two pulmonologists, two pathologists, and two OCT experts) were trained on imaging criteria in a 15-min training session prior to interpreting the validation data set. Results: OCT of lung parenchyma displayed evenly spaced signal-void alveolar spaces, signal-intense backrefl ections at tissue-air interfaces, or both. SPNs lacked both of these imaging features. Independent validation of OCT criteria by the six blinded readers demonstrated sensitivity and specifi city of 95.4% and 98.2%, respectively. Conclusions: We have developed and validated OCT criteria for lung parenchyma and SPN with sensitivity and specifi city . 95% in this ex vivo study. We anticipate that OCT could be a useful complementary imaging modality to confi rm needle placement during TBNA to potentially increase diagnostic yield. CHEST 2013; 144(4):1261-1268Abbreviations: OCT 5 optical coherence tomography; SPN 5 solitary pulmonary nodule; TBNA 5 transbronchial needle aspiration; TB-OCT 5 transbronchial optical coherence tomography

Flexible needle with integrated optical coherence tomography probe for imaging during transbronchial tissue aspiration

“…30). Detailed interpretation of the structural features present is complicated by both OCT imaging artifacts and effects of the needle insertion and will require larger studies to define appropriate criteria, such as those presented by Hariri et al 9 Longitudinal B-scans ( Fig. 3) were constructed as the needle was manually translated interstitially.…”

“…However, accurate positioning of the needle tip relative to the lesion or node is difficult, often resulting in nondiagnostic tissue samples (i.e., samples that do not yield a definitive pathology). 8 Slight misplacement of the needle tip will position it in nearby uninvolved tissue, such as lung parenchyma 9 or adipose. 10 There is clinical evidence that diagnostic yields of both endobronchial ultrasound (EBUS)guided and unguided TBNA are low (as low as 33% and 14%, respectively), particularly in pulmonary nodules or lymph nodes smaller than 20 mm.…”

“…15,16 OCT has previously been demonstrated to be capable of differentiating uninvolved and malignant pulmonary tissue. 9,[17][18][19] Preliminary work has also demonstrated that OCT has the potential for integration into needles for differentiation of tissue types. [20][21][22] In particular, a needle probe designed for guiding TBNA 21 has been demonstrated in a previous study.…”

“…We illustrate the feasibility of this approach with an in situ experiment in a sheep lung and show clear distinction between solid tissue, adipose, and lung parenchyma. The capacity to identify adipose and lung parenchyma, which are typical constituents of nondiagnostic samples, 9,10,25 provides an opportunity for OCT needles to avoid sampling these normal tissues and improve the diagnostic yield during TBNA. To the best of our knowledge, this is the first demonstration of a flexible endoscopic needle with integrated OCT imaging capable of simultaneous imaging and tissue aspiration.…”

Optimal endobronchial tool sizes for targeting lung lesions based on 3D modeling

“…There are many types of new lung tools that have been reported in the literature and some that are now entering the market. These new tools aim to improve diagnostic yield by providing better navigational guidance to the lesion (example, EM tracking [ 18 , 19 , 20 ]) or by evaluating the tissue prior to biopsy (examples, EBUS [ 21 ], radial endobronchial ultrasound [REBUS] [ 21 ], optical coherence tomography [ 22 , 23 , 24 , 25 , 26 , 27 ], fluorescence spectroscopy [ 28 , 29 ], diffuse reflectance spectroscopy [ 28 , 29 , 30 ], Raman spectroscopy [ 31 , 32 , 33 ], or differential path length spectroscopy [ 30 , 34 , 35 , 36 ]). These new tools will improve diagnostic yield but only if they can physically reach the lesion.…”