Endoscopic optical coherence tomography angiography microvascular features associated with dysplasia in Barrett's esophagus (with video)

Abstract

Background and aims: Angiogenesis is associated with neoplastic progression of Barrett's esophagus (BE). Volumetric optical coherence tomography angiography (OCTA) visualizes subsurface microvasculature without exogenous contrast agents. We investigated the association of OCTA microvascular features with low-grade dysplasia (LGD) and high-grade dysplasia (HGD).

Methods: Fifty-two patients undergoing BE surveillance or endoscopic eradication therapies for dysplasia were imaged using volumetric OCTA and corresponding histologic diagnoses wre obtained to yield 97 data sets (nondysplastic BE [NDBE], 74; LGD, 10; HGD, 13). After evaluating OCTA image quality, 54 datasets (NDBE, 35; LGD, 8; HGD, 11) from 32 patients were used to develop a training and reading protocol. The association of abnormal vessel branching and heterogeneous vessel size with LGD/HGD and a regular honeycomb vessel pattern with NDBE were investigated.

Results: Blinded OCTA reading of 41 OCTA datasets (NDBE, 27; LGD, 7; HGD, 7) was performed by readers with various levels of OCT/OCTA experience including 3 OCT trainees, 1 gastroenterologist, and 2 gastroenterology fellows. Among the 6 readers, OCTA features of abnormal vessel branching and heterogeneous vessel size had an overall 94% sensitivity (95% CI, 89-99) and 69% specificity (95% CI, 62-76) for differentiating LGD/HGD versus NDBE with a mean reading time of 45 seconds per data set and moderate (kappa = .58) interobserver agreement.

Conclusions: Volumetric en face OCTA imaging enables rapid examination of depth resolved microvascular features with near-microscopic resolution. OCTA can visualize microvascular features associated with LGD/HGD with high accuracy, which motivates new technologic advances and future studies investigating the diagnostic performance of OCTA.

Figure 1

Flow chart illustrating the OCT/OCTA imaging procedure and collection of the corresponding histology.

Figure 2

Flow chart summarizing the image processing steps for generating depth-resolved en face OCT angiography (OCTA) images from the structural volumetric OCT dataset. A_n is linear OCT signal amplitude in individual OCT frames. A nonuniform rotational distortion (NURD) correction algorithm was used before calculating decorrelation between consecutive cross-sectional OCT images.

Figure 3. En face

OCT angiography (OCTA) images of (A–C) non-dysplastic BE (NDBE) and (D–F) dysplastic BE (LGD: F; HGD: D, E) from ~180 μm beneath the tissue surface. NDBE exhibited regular honeycomb microvascular pattern (arrows, A–C), similar to previously reported with NBI. The shape of the honeycomb features may be compressed or stretched along the longitudinal direction due to motion artifacts. High decorrelation noise from physiological motion can also be observed (stars, B, C). Abnormal vascular features including (1) abnormal vessel branching (arrows, D), (2) heterogeneous vessel size (arrows, E) or both (F) were shown. OCTA allowed delineation of the boundary between abnormal microvasculature and neighboring non-dysplastic regions (dashed line, D, E). (G–I) NBI images near the imaged sites (D–F) respectively (circles). Scale bars: 1 mm. SE: squamous epithelium. Insets (G, H, I): H&E stained histopathology images of the specimens from the imaged sites corresponding to the histological diagnosis of HGD, HGD, and LGD, respectively. r: rotary direction; x: longitudinal (pullback) direction.