In Vivo, Percutaneous, Needle Based, Optical Coherence Tomography of Renal Masses

The aim of this project is to demonstrate the feasibility of percutaneous needle based optical coherence, tomography of renal masses. Knowledge and experience gained in optical coherence tomography, or OCT is now being implemented in vivo in the kidney. The development of OCT into an optical biopsy has been prompted by the clinical need for an accurate and easy technique.

For tumor differentiation. We aim to develop OCT to an optical biopsy providing real-time imaging with on the spot tumor differentiation. This Video will start off with a schematic representation of the full procedure.

Afterwards, we will show you the real video of the procedure that takes place in our individual radiology rooms Using ultrasound, localize the tumor and mark the needle entry point on the skin. Using a needle guide, place the 15 gauge coaxial introducer needle. Place the 18 gauge trocar needle feed the OCT probe up the trocar needle.

While fixing the OCT probe, retract the trocar needle. To expose the OCT probe, perform an OCT scan. Remove the OCT probe and trocar needle.

Place the core biopsy gun through the introducer needle. If the positioning is satisfactory, fire the biopsy gun. In this demonstration, we use the commercially available ilumien optis OCT system connected to a dragonfly duo intravascular imaging probe.

The dragonfly duo is a rotational probe scanning at a 90 degree angle. It has an outer diameter of 2.7 French 0.9 millimeters and an insertable length of 135 centimeters. Prior to starting the procedure, a timeout procedure is performed.

Depending on the location of the tumor, the patient is placed in either prone or lateral positioning. Provide the patient with adequate support and verify if he or she expects to be comfortable in this position. Over a 20 to 40 minute period, using ultrasound, localize the tumor and mark the needle entry point on the skin with permanent ink, clean the skin around the puncture side using a chlorhexidine alcohol solution.

Taking care not to remove the previously placed needle entry mark with regard to the sterile content. Open the percutaneous puncture set wash hands thoroughly applying hand disinfectant afterwards, put on a surgical gown and sterile gloves. Cover the patient in sterile drapes.

Apply a sterile cover around the ultrasound probe and fix the needle guide to the probe. Start the console and enter the patient details. Apply the sterile cover to the OCT console mounting dock.

Fill the five milliliter syringe with oh 0.9%sodium chloride solution and attach it to the probe flushing port. Flush the OCT probe until water appears in the distal part of the probe cover. Load the OCT probe into the mounting dock, Leaving the probe in its protective cover.

During flushing mounting, minimize the risk probe damage. Place the probe on a hard surface and use the scalpel to shorten the tip. Cut five millimeters distal from prism using the emitted light for orientation.

Fix the distal part of the probe during cutting. In order to minimize pressure on the fiber and prism, anesthetize the skin and deep layers using lidocaine 2%Wait several minutes, allowing for the lidocaine to take effect. Instruct the patient to inform you in case of pain.

Using a needle guide, place the 15 gauge coaxial introducer needle, verifying the position through imaging. If placement is satisfactory, remove the obturator place the 18 gauge trocar needle through the introducer needle. Piercing the tumor, verifying the position of the needle with imaging.

If placement is satisfactory, remove the obturator. Feed the OCT probe up the trocar needle until feeling resistance. While fixing the OCT probe, retract the trocar needle to expose the OCT probe to the tumor tissue.

Keeping the tip of the trocar needle within the tumor minimizes kinking of the OCT probe during breathing cycles, lowering the risk of probe damage. Perform an OCT scan with a console set at 541 B scans per dataset. Check the scan for quality artifacts and the appearance of solid tissue.

Repeat scanning until a minimum of three OCT data sets is acquired. Remove the OCT probe and trocar needle, leaving the introducer needle in place. Arm the core biopsy gun and place it through the introducer needle.

Verifying the position on imaging. If the positioning is satisfactory, fire the biopsy gun place biopsy material in a container according to pathology department protocol. Repeat the biopsy until sufficient material has been obtained.

Raw data files and TIF files are exported from the OCT console. A 3D volume is rendered from the raw data with the Amira software package. This provides a 3D overview of the scanned trajectory.

A clear visual distinction can be made as the scan passes through solid tissue, perineal fatty tissue, and ends up inside the trocar needle. Exported TIFF files can be loaded into Fiji to be viewed in 2D by scrolling through the stacked B scans. Combining a mirror and Fiji, an area of interest is selected within the area of interest.

Equally spaced B scans are selected within the respective B scans. The attenuation coefficient can be determined along a straight line radiating outward from the heart of the probe. Fiji has the option of plotting the data points along the attenuation line, creating a graph.

The slope of the displayed graph represents the attenuation coefficient or the loss of signal intensity per millimeter of tissue penetration. By correlating attenuation measurements to histopathology results, tissue specific cutoff values can be derived. Providing the means for tumor differentiation.

A percutaneous approach is essential in the development of OCT into a clinically applicable optical biopsy. This video, we’ve shown you how we perform percutaneous ultrasound guided OCT of renal mass.