Juliet Ippolito

Differential in vivo urodynamic measurement in a single thin catheter based on two optical fiber pressure sensors

Abstract. Urodynamic analysis is the predominant method for evaluating dysfunctions in the lower urinary tract. The exam measures the pressure during the filling and voiding process of the bladder and is mainly interested in the contraction of the bladder muscles. The data arising out of these pressure measurements enables the urologist to arrive at a precise diagnosis and prescribe an adequate treatment. A technique based on two optical fiber pressure and temperature sensors with a resolution of better than 0.1  cm H2O (∼10  Pa), a stability better than 1  cm H2O/hour, and a diameter of 0.2 mm in a miniature catheter with a diameter of only 5 Fr (1.67 mm), was used. This technique was tested in vivo on four patients with a real-time urodynamic measurement system. The optical system presented showed a very good correlation to two commercially available medical reference sensors. Furthermore, the optical urodynamic system demonstrated a higher dynamic and better sensitivity to detect small obstructions than both pre-existing medical systems currently in use in the urodynamic field.

Fiber-Optic EFPI Pressure Sensors for In Vivo Urodynamic Analysis

A fiber optic sensing system for pressure measurement in invasive urodynamics is presented and experimentally validated. Probes are based on extrinsic Fabry-Perot interferometry (EFPI) principle, with an all-glass biocompatible design having 0.2-mm thickness. Pressure sensitivity of 1.0-1.6 nm/kPa with high stability and reduced thermal sensitivity has been achieved, leading to 0.3-cmH2O pressure accuracy. The EFPI probes have been embedded in medical catheters with 4F size for dual bladder and abdominal pressure measurement throughout the full course of a urodynamic analysis. Pressure traces have been compared with a PICO2000 urodynamic instrument, showing improved accuracy and higher responsivity to local pressure variations. Tests have been carried out in vivo on seven patients; the main highlights are reported, showing the premises for an EFPI-based diagnostic tool.

Temperature profile of ex-vivo organs during radio frequency thermal ablation by fiber Bragg gratings

Abstract. We report on the integration of fiber optic sensors with commercial medical instrumentation for temperature monitoring during radio frequency ablation for tumor treatment. A suitable configuration with five fiber Bragg grating sensors bonded to a bipolar radio frequency (RF) probe has been developed to monitor the area under treatment. A series of experiments were conducted on ex-vivo animal kidney and liver and the results confirm that we were able to make a multipoint measurement and to develop a real-time temperature profile of the area, with a temperature resolution of 0.1°C and a spatial resolution of 5 mm during a series of different and consecutive RF discharges.

Temperature monitoring during thermal ablation on ex-vivo organs by Fiber Bragg gratings

In this paper we report on the application of Fiber Bragg gratings (FBGs) for temperature monitoring during radiofrequency ablation (RFA) for tumor treatment. A proper configuration with several FBG sensors deployed close to the region reached by RF discharges has been developed to monitor the necrotized area. Our ex-vivo experiments on animal kidney and liver confirm that we were able to monitor the temperature with a resolution of 0.1 °C during a series of different and consecutive RF discharges with the laparoscopic bipolar radiofrequency device Habib 4x.

Measurements of temperature during thermal ablation treatments on ex vivo liver tissue using fiber Bragg grating sensors

In this work, we propose the use of fiber Bragg grating (FBG) sensor arrays for real-time temperature monitoring during RadioFrequency Thermal Ablation (RFTA) tumor treatment. Real-time temperature monitoring of RF-treatment to the tumors lesion of an organ could prove to be highly beneficial for intra-operative surgical planning and subsequently ensure a successful outcome of a thermo-ablation procedure. An adequate configuration was designed in order to create a thermal multipoint map. In particular, the RF probe of a commercial medical device was properly packaged with FBG sensors. In order to discern the treatment areas as accurately as possible, a second 3.5 cm long array, consisting of several FBGs was also employed. The experiments were conducted on ex vivo animal liver tissues and results confirm that we were successfully able to conduct a multipoint measurement and to distinguish between different and consecutive RF discharges with a temperature resolution of 0.1 °C and a minimum spatial resolution of 5mm.

Real-time temperature monitoring during radiofrequency treatments on ex-vivo animal model by fiber Bragg grating sensors

Fiber Bragg Grating (FBG) sensors applied to bio-medical procedures such as surgery and rehabilitation are a valid alternative to traditional sensing techniques due to their unique characteristics. Herein we propose the use of FBG sensor arrays for accurate real-time temperature measurements during multi-step RadioFrequency Ablation (RFA) based thermal tumor treatment. Real-time temperature monitoring in the RF-applied region represents a valid feedback for the success of the thermo-ablation procedure. In order to create a thermal multi-point map around the tumor area to be treated, a proper sensing configuration was developed. In particular, the RF probe of a commercial medical instrumentation, has been equipped with properly packaged FBGs sensors. Moreover, in order to discriminate the treatment areas to be ablated as precisely as possible, a second array 3.5 cm long, made by several FBGs was used. The results of the temperature measurements during the RFA experiments conducted on ex-vivo animal liver and kidney tissues are presented herein. The proposed FBGs based solution has proven to be capable of distinguish different and consecutive discharges and for each of them, to measure the temperature profile with a resolution of 0.1 °C and a minimum spatial resolution of 5mm. Based upon our experiments, it is possible to confirm that the temperature decreases with distance from a RF peak ablation, in accordance with RF theory. The proposed solution promises to be very useful for the surgeon because a real-time temperature feedback allows for the adaptation of RFA parameters during surgery and better delineates the area under treatment.

In-Vivo Urodynamic Pressure Measurement with Fiber-Optic EFPI Pressure Probes

Urodynamic analysis carried out with biocompatible catheterized fiber-optic probes, for dual measurement of pressure in bladder and in rectum, is presented. Medical tests have been performed in-vivo on seven patients; main highlights are reported.

Low drift and high resolution miniature optical fiber combined pressure- and temperature sensor for cardio-vascular and urodynamic applications

The all-glass optical fibre pressure and temperature sensor (OFPTS), present here is a combination of an extrinsic Fabry Perot Interferometer (EFPI) and an fiber Bragg gratings (FBG), which allows a simultaneously measurement of both pressure and temperature. Thermal effects experienced by the EFPI can be compensated by using the FBG. The sensor achieved a pressure measurement resolution of 0.1mmHg with a frame-rate of 100Hz and a low drift rate of < 1 mmHg/hour drift. The sensor has been evaluated using a cardiovascular simulator and additionally has been evaluated in-vivo in a urodynamics application under medical supervision.

Fiber optic extrinsic Fabry-Perot interferometry pressure sensors for in-vivo urodynamic analysis

We report a fiber-optic sensing system based on Extrinsic Fabry-Perot Interferometry (EFPI), for pressure detection in medical applications. The system allows dual channel detection, with probes having typical sensitivity of 1.3 nm/kPa and accuracy of 0.6 cmH2O, diameter of 0.2 mm, and perfect biocompatibility. Pressure probes have been applied to urodynamic analysis, measuring both bladder and abdominal pressure. Measurements have been carried out in-vivo on seven patients having different bladder conditions. The fiber-optic probes have been compared with a PICO2000 urodynamic instrument, showing improved accuracy, a good reproduction of bladder-related events, and increased responsivity to local pressure variations.