In vivo bladder imaging with microelectromechanical-systems-based endoscopic spectral domain optical coherence tomography

Abstract

We report the recent technical improvements in our microelectromechanical systems (MEMS)-based spectral-domain endoscopic OCT (SDEOCT) and applications for in vivo bladder imaging diagnosis. With the technical advances in MEMS mirror fabrication and endoscopic light coupling methods, the new SDEOCT system is able to visualize morphological details of the urinary bladder with high image fidelity close to bench-top OCT (e.g., 10 mum12 mum axial/lateral resolutions, >108 dB dynamic range) at a fourfold to eightfold improved frame rate. An in vivo animal study based on a porcine acute inflammation model following protamine sulfate instillation is performed to further evaluate the utility of SDEOCT system to delineate bladder morphology and inflammatory lesions as well as to detect subsurface blood flow. In addition, a preliminary clinical study is performed to identify the morphological features pertinent to bladder cancer diagnosis, including loss of boundary or image contrast between urothelium and the underlying layers, heterogeneous patterns in the cancerous urothelium, and margin between normal and bladder cancers. The results of a human study (91% sensitivity, 80% specificity) suggest that SDEOCT enables a high-resolution cross-sectional image of human bladder structures to detect transitional cell carcinomas (TCC); however, due to reduced imaging depth of SDEOCT in cancerous lesions, staging of bladder cancers may be limited to T1 to T2a (prior to muscle invasion).

Colposcopic imaging using visible-light optical coherence tomography

“…Most reported systems acquire two-dimensional (2-D) circular cross-sectional images using a DC motor, microelectro-mechanical system (MEMS), or fiber optic rotary joint. 12,15,[23][24][25][26][27][28] To achieve 3-D imaging, a pullback mechanism along the probe can be added either manually or mechanically. [29][30][31][32] In colposcopic imaging, however, the OCT probe does not require flexibility and only needs a relative short probe length (around 10 cm).…”

Nonionizing photoacoustic cystography in vivo

“…X-ray computed tomography has been applied, but it is ionizing and not sensitive. Contrast-enhanced MRI has been applied, but it is expensive and bulky [1]. Although ultrasound (US) imaging is real-time, portable, relatively cost effective, and safe, conventional US imaging is not sensitive, especially, for imaging bladder cancers [2].…”

Endoscopic optical coherence tomography: technologies and clinical applications [Invited]

“…With early systems, it has been shown that OCT has 100% sensitivity and 89% specificity for diagnosing transitional cell carcinoma based on differentiating its OCT appearance from inflammation and dysplasia [172]. Introduction of MEMS-based micro scanning mechanisms enabled further improvement of OCT probes, resulting in 4.5mm long scans at 8fps allowing for combining cross-sectional information with information about mucosal blood flow [173]. Using commercially available laparoscopic system, OCT was shown to be capable of staging tumors, including identifying muscle-invasive bladder tumors [174], reducing false-positive findings of fluorescence cystoscopy (Fig.…”