Imaging collector channel entrance with a new intraocular micro-probe swept-source optical coherence tomography

PURPOSE

To describe the use of a newly developed side-viewing catheter probe to provide the cross-sectional images of collector channel entrance (CCE), achieved by swept-source optical coherence tomography (SS-OCT).

METHODS

A side-viewing SS-OCT catheter probe was developed that has a core probe diameter of 0.15 mm and an outer diameter of 0.25 mm, for the purpose of imaging CCEs within eye globe. Cadaver eyes harvested from swine and human were used to demonstrate its feasibility. For porcine eyes, the probe imaged the CCE by accessing the region of the aqueous plexus (AP) as well as along the inner wall (IW) of the trabecular meshwork (TM). For human eyes, the CCE images were captured by placing the probe within the lumen of the Schlemm's canal (SC) and along its IW.

RESULTS

With the optical coherence tomography (OCT) catheter probe, the CCE is well delineated as optically empty areas within the highly scattering sclera. In porcine eyes, images captured in the region of the AP demonstrate a large cavity with delicate tissue strands around the probe. The CCE can be identified at the outer margin of the AP. When imaged along the IW, the TM is discernable but difficult to be distinguished from the AP. In the human limbal regions, when placed within the lumen of the SC, the catheter probe fully occupies the potential space. TM is highly compact. The CCE can be identified at the outer wall of the SC. When imaged along the IW of TM, the SC and CCE can be identified.

CONCLUSION

The intraocular SS-OCT catheter probe is feasible to provide the CCE images, indicating useful clinical applications to assist glaucoma surgery.

Wire-guided intraduodenal ultrasonography using a catheter probe in the differential diagnosis of enlarged ampullary lesions

BACKGROUND AND AIM

It can be difficult to identify the cause of an enlarged ampulla of Vater (AOV). This study evaluated the accuracy of wire-guided intraduodenal ultrasonography (US) for the differential diagnosis of an enlarged AOV during endoscopic retrograde cholangiopancreatography (ERCP).

PATIENTS AND METHODS

Thirty-four patients with enlarged AOVs of unknown cause identified on imaging studies or endoscopic observations underwent wire-guided intraduodenal US using a catheter probe.

RESULTS

The final diagnoses were malignant or premalignant tumors in 10 patients (29.4%), stones in nine patients (26.5%), inflammation in 14 patients (41.2%), and cyst in one patient (2.9%). The overall diagnostic accuracy of intraduodenal US for enlarged AOVs was 91.2%. The diagnostic accuracies of stones, inflammation, and AOV tumors were 100.0%, 94.1%, and 91.1%, respectively.

CONCLUSIONS

Wire-guided intraduodenal US using a catheter probe is readily applicable during ERCP and may be useful in the differential diagnosis of enlarged ampullary lesions.