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

Summary

Optical coherence tomography (OCT) is a high resolution imaging technique that allows analysis of tissue specific optical properties providing the means for tissue differentiation. We developed needle based OCT, providing real-time imaging combined with on-the-spot tumor differentiation. This publication describes a method for percutaneous, needle based OCT of renal masses.

Abstract

Optical coherence tomography (OCT) is the optical equivalent of ultrasound imaging, based on the backscattering of near infrared light. OCT provides real time images with a 15 µm axial resolution at an effective tissue penetration of 2-3 mm. Within the OCT images the loss of signal intensity per millimeter of tissue penetration, the attenuation coefficient, is calculated. The attenuation coefficient is a tissue specific property, providing a quantitative parameter for tissue differentiation.

Until now, renal mass treatment decisions have been made primarily on the basis of MRI and CT imaging characteristics, age and comorbidity. However these parameters and diagnostic methods lack the finesse to truly detect the malignant potential of a renal mass. A successful core biopsy or fine needle aspiration provides objective tumor differentiation with both sensitivity and specificity in the range of 95-100%. However, a non-diagnostic rate of 10-20% overall, and even up to 30% in SRMs, is to be expected, delaying the diagnostic process due to the frequent necessity for additional biopsy procedures.

We aim to develop OCT into an optical biopsy, providing real-time imaging combined with on-the-spot tumor differentiation. This publication provides a detailed step-by-step approach for percutaneous, needle based, OCT of renal masses.

Introduction

The past decades have shown a steady increase in the incidence of renal masses ^1,2. Until now, renal mass treatment decisions have been made primarily on the basis of MRI and CT imaging characteristics, age and comorbidity. However these diagnostic methods and clinical parameters lack the finesse to truly detect the malignant potential of a renal mass. A core biopsy or fine needle aspiration with sufficient tissue for pathological evaluation (diagnostic) provides objective tumor differentiation with both sensitivity and specificity in the range of 95-100% ³. Therefore biopsy is gaining acceptance in the evaluation of suspicious renal masses ^....

Protocol

The presented procedure takes place under a research protocol approved by the Institutional Review Board of the Academic Medical Center Amsterdam, registration number NL41985.018. Written informed consent is required from all participants.

1. System

1. For this experiment, use a Fourier domain OCT system, operating at a 1,280–1,350 nm wavelength band ¹³. Fourier domain low-coherence interferometry allows for continuous scanning which increases the data acquisition speed when compared to the first generation time-domain OCT systems. Note: The OCT system is interfaced with a fiber optic probe, scanning helically at ~....

Results

Among the first 25 tumors (23 patients), a total of 24 successful OCT procedures were performed. In one case a probe malfunction led to the inability to acquire an OCT scan. Two adverse events (AE) occurred, which are described in detail in the discussion section. General patient characteristics are found in Table 1.

The OCT console has pre-installed software providing real-time OCT images for immediate qualitative analysis of acquired datasets. For further analysis and attenu.......

Discussion

In this publication we report on the feasibility of percutaneous, needle based, OCT of the kidney. This is an essential first step in the development of OCT into a clinically applicable technique for tumor differentiation, termed as an “Optical Biopsy”. Our first 25 patients have shown percutaneous OCT to be an easy and safe procedure. An optical biopsy has two advantages over conventional core biopsies. First, the real time acquisition and analysis of OCT data will provide instant diagnostic results, compare.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
15 G/7.5 cm Co-Axial Introducer Needle	Angiotech, Gainesville, USA	MCXS1612SX
18 G/20 cm Trocar Needle	Cook medical, Bloomington, USA	DTN-18-20.0-U
16 G/20 cm Quick-Core Biopsy Gun	Cook Medical, Bloomington, USA	G07827
Ilumien Optis PCI Optimization System (OCT & FFR)	St. Jude medical, St. Paul, USA	C408650	Part of Dragonfly Kit. St. Jude medical, St. Paul, USA. (C4088643)
Dragonfly Duo Imaging Catheter	LightLab Imaging, Westford, USA	C408644	Part of Dragonfly Kit. St. Jude medical, St. Paul, USA. (C4088643)
Sterile Dock Cover	CFI Med. Solutions, Fenton, USA	200-700-00	Part of Dragonfly Kit. St. Jude medical, St. Paul, USA. (C4088643)
5 ml Luer-lock Syringe	Merit Med. Syst., South Jordan, USA	C408647
10 ml Syringe	BD, Franklin Lakes, USA	300912
18 G Blunt Fill Needle	BD, Franklin Lakes, USA	305180
21 G Injection Needle	BD, Franklin Lakes, USA	301155
Sterile scalpel	BD, Franklin Lakes, USA	372611
NaCl 0,9% solution	Braun, Melsungen AG, Germany	222434
Lidocaïne HCl 2% (20 mg/ml) solution	Braun, Melsungen AG, Germany	3624480
Sterile Ultrasound Gel, Aquasonic 100	Parker Lab. Inc., Fairfield, USA	GE424609
Sterile Ultrasound Cover	Microtek Med., Alpharetta, USA	PC1289EU
Pathology Container
AMIRA software package	FEI Visualization Sciences Group, Hillsboro, USA	Software platform for 3D data analysis
FIJI software package (open source)	Open source, http://fiji.sc/Fiji		Open source image processing software