Advances in digital imaging during endoscopic surgery

Digital ureteroscopes: technology update

The field of ureteroscopy has undergone a continual evolution since the first ureteroscopes were introduced. Over the past 10 years, we have entered into the digital era of ureteroscopy with both semirigid and flexible options becoming available. The following review looks at the benefits and drawbacks of digital flexible ureteroscopes as well as the current commercially available options.

A new world revealed: early experience with digital ureteroscopy

PURPOSE

The latest digital ureteroscope, the DUR-D (Gyrus ACMI Inc., Southborough, Massachusetts) offers image quality that greatly exceeds current analog image capabilities. The purpose of this report was to document the applicability of this device in studying the earliest stages of stone formation.

MATERIALS AND METHODS

Symptomatic patients with nephrolithiasis (less than 1 cm in diameter) were prospectively enrolled and their renal papilla digitally mapped prior to stone removal. Recovered stones were photographed and analyzed using micro-computerized tomography. If the procedure could not be completed with the DUR-D, a conventional ureteroscope was used. Minors, pregnant patients and those with systemic disorders were excluded.

RESULTS

Eight patients (10 renal units), 2 cystine and 6 calcium oxalate stone formers, were studied with a mean age of 50.1 years. Excellent images were collected for all papilla except in 2 cases; a proximal ureteral stricture and acute angulation of the lower pole collecting system, respectively. There were no mechanical device failures. Of the 10 renal units 7 had stents postoperatively and there were no patient complications.

CONCLUSIONS

The ease of use and high quality images of digital ureterorenoscopy will allow the documentation of the earliest stages of calcium oxalate stone formation and, thereby, advance our understanding of the pathogenesis of calcium oxalate stone formation.

Physically motivated enhancement of color images for fiber endoscopy

Fiber optics are widely used in flexible endoscopes which are indispensable for many applications in diagnosis and therapy. Computer-aided use of fiberscopes requires a digital sensor mounted at the proximal end. Most commercially available cameras for endoscopy provide the images by means of a regular grid of color filters what is known as the Bayer Pattern. Hence, the images suffer from false colored spatial moiré, which is further stressed by the downgrading fiber optic transmission yielding a honey comb pattern. To solve this problem we propose a new approach that extends the interpolation between known intensities of registered fibers to multi channel color applications. The inventive idea takes into account both the Gaussian intensity distribution of each fiber and the physical color distribution of the Bayer pattern. Individual color factors for interpolation of each fiber area make it possible to simultaneously remove both the comb structure from the fiber bundle as well as the Bayer pattern mosaicking from the sensor while preserving depicted structures and textures in the scene.

An optical evaluation of the phenomenon of red out in neuroendoscopic surgery: what is the physical background?

BACKGROUND

The loss of visualization in neuroendoscopy due to intraoperative bleeding is called "red out". Although red out is a well-known problem during endoscopy, clear physical descriptions of this phenomenon are lacking.

OBJECTIVE

The aim of this study was to investigate the optical properties of red out. In particular, the attenuation coefficient, comprising scattering, and absorption, of various blood/Ringer solutions was quantified and measured spectrally resolved. Small amounts of blood virtually preclude neuroendoscopic visualization. In blood/Ringer solutions with a dilution of 1:101, it was not possible to distinguish characters (font size 10, Arial) at a distance of 5 mm. We have concluded, from our physical investigations, that the problem of red out is dominated by scattering rather than by absorption. Accordingly, technical developments aimed at increasing information acquisition under red out conditions should be based on optical measurement concepts for scattering media.

Automatic Adaptive Enhancement for Images Obtained With Fiberscopic Endoscopes

Modern techniques for medical diagnostics and therapy in keyhole surgery scenarios as well as technical inspection make use of flexible endoscopes. Their characteristic bendable image conductor consists of a very limited number of coated fibers, which leads to so-called comb structure. This effect has a negative impact on further image processing steps such as feature tracking because these overlaid image structures are wrongly detected as image features. With respect to these tasks, we propose an automatic approach to generate optimal spectral filter masks for enhancement of fiberscopic images. We apply the Nyquist-Shannon sampling theorem to the spectrum of fiberscopically acquired images to obtain parameters for optimal filter mask calculation. This can be done automatically and independently of scale and resolution of the image conductor as well as type and resolution of the image sensor. We designed and verified simple rotation invariant masks as well as star-shaped rotation variant masks that contain information about orientation between the fiberscope and sensor. A subjective survey among experts between different modes of filtering certified the best results to the adapted star-shaped mask for high-quality glass fiberscopes. We furthermore define an objective metric to evaluate the results of different filter approaches, which verifies the results of the subjective survey. The proposed approach enables the automated reduction of fiberscopic comb structure. It is adaptive to arbitrary endoscope and sensor combinations. The results give the prospect of a large field of possible applications to reduce fiberscopic structure both for visual optimization in clinical environments and for further digital imaging tasks.

The camera phone: A novel aid in urologic practice

OBJECTIVES

To describe a novel use of the camera phone for efficient, reliable, and cost-effective collection and transmission of medical data in the urologic setting.

METHODS

We used camera phones (Verizon VGA and Sanyo-Sprint PCS) with a resolution of 640 x 480 pixels to capture images in the operating room, as well as in the outpatient clinic. Images were obtained directly from the monitor or the x-ray viewing box. These were then immediately transmitted to the office computer through a secure Internet connection. The images were then incorporated into operative and office notes, as needed.

RESULTS

The images obtained with this method were of adequate quality for demonstration purposes, with the added advantage of allowing secure transmission and storage. The best-quality images were those obtained directly from the x-ray viewing box or from a liquid crystal display monitor. In addition, the images could be edited and labels added with the aid of the software that came with the camera phone.

CONCLUSIONS

This method allows the acquisition of fair-quality digital images of surgical procedures and radiographic studies with simultaneous data transmission and storage for clinical documentation. The technology reduced costs and increased the efficiency of our practice considerably.

Advances in video and imaging in ureteroscopy

Advances in image processing and display technologies, such as digital imaging, HDTV, and virtual reality, will ultimately allow integration of endoscopic imaging with diagnosis and therapy during ureteroscopic procedures. Further improvements in simulation technology and telemedicine should improve surgical training and greatly benefit patient care.

Experience with flexible video cystoscope equipped with built-in high-frequency cauterizing element for transurethral resection of the bladder

We successfully treated three patients using the flexible video cystoscope (CYF-240A, Olympus, Japan) for superficial bladder cancer under local anesthesia and/or spinal anesthesia. The major advantage of this new technique is that surgeons can use digital pictures and high frequency cauterization. This new system provides good quality of life for bladder cancer patients experiencing frequent recurrences.

Endoscopic data acquisition and storage

Recent developments in the field of digital image acquisition and storage provide new opportunities for recording endoscopic procedures for use in the medical record and remote access for education and consultation. This article reviews the recent literature in the field of endoscopy.

Flexible video cystoscope with built-in high-frequency cauterizing element for transurethral resection of bladder tumor

The major advantage of the flexible video cystoscope is that a digital signal can be obtained while high frequency cauterization is carried out. Cauterization while observing a digital signal picture was not possible before this new model was developed. We decided to use this new cystoscope to resect a bladder tumor and coagulate the bleeding because the patient could tolerate only local anesthesia due to severe heart disease complications. We successfully treated the patient with this technique and no complications were noted. This new flexible video cystoscope was found to be safe for resecting bladder tumor under local anesthesia.

Advances in camera, video, and imaging technologies in laparoscopy

The introduction of technological advances, such as HDTV, three-dimensional laparoscopy, and further miniaturization of high-resolution digital video cameras, will allow significantly enhanced opportunities for laparoscopic surgical proficiency and further broadening of laparoscopic applications in urology. These enhancements, coupled with the recent advances in telemedicine and surgical simulation, will improve laparoscopic training and skill acquisition, decrease operative times and costs, minimize morbidity, and improve overall patient care.

Current urologic applications of digital imaging

One of the most significant developments in imaging technology has been the process of digitalization. By incorporating currently available digital imaging equipment into surgical practice, urologists can be assured of obtaining real-time video images with optimal clarity and detail. In addition, one can efficiently capture and store still images that are crisper and sharper than their analog counterparts. These factors greatly improve the diagnostic capabilities and organization of today's endourologist.

Telemedicine: recent developments and future applications

Telemedicine, or the delivery of health care from a distance, is an exciting field that has undergone rapid advancements over the past three decades. Previous studies have demonstrated that telemedicine can effectively assist in patient care. However, cost issues and the lack of resources to sustain telemedicine systems have previously limited the use of this technology. Herein, we explore the development, current applications, and future of telemedicine.

Digital still image recording during video endoscopy

With the advances in telemedicine and virtual consultation services comes the need for state-of-the-art endoscopic imaging techniques and equipment. Concomitant with current day concerns of cost containment, the ability to utilize the aforementioned tools in a cost-effective fashion that lowers operating expenses, accurately depicts procedures, and expedites chart documentation is paramount. We report on a fast and efficient way to obtain and store images during endoscopic procedures, which can be stored on standard 3.5-inch floppy disks using an innovative digital image recorder. These images are stored as high-resolution (640x480x24) JPEG files, which can be placed in electronic medical records, imported into Internet Web pages, incorporated into slide presentations, and, most importantly, stored in easily accessed archives.