Brian L. Craine

The computerized digital imaging colposcope: future directions.

A computer-aided colposcope has been developed for enhancement and analysis of colposcopic images. There are numerous possible applications of this system, including image archiving, image enhancement and processing, and quantitative measurements of various features in the images. In addition, a wide range of digital filters can be applied to the system that may be used to detail different aspects of the image. The method for a new mode of applying digital and optical filters to the colposcope is discussed and future directions for the system are suggested.

Digital imaging colposcopy: corrected area measurements using shape-from-shading

The quantitative measurement of areas on the cervix is of interest to researchers studying the natural history of human papilloma viral lesions. Measurement of areas from images obtained through a colposcope are, however, inherently in error due to the image being a two-dimensional projection of a three-dimensional object. The ability to correct for these errors through use of digital imaging colposcopy and a practical application of a shape from shading algorithm was developed in this study. The shape from shading technique requires empirical measurement of the relationship between observed light intensity and the viewing angle (referred to as a reflection map). It was found that a population mean reflection map provided a correction that was about as accurate as using an individuals own reflection map (making it unnecessary to measure a map for each exam). Digital red filtering of the images increased accuracy and precision of measurement.

Computerized auscultation applied to irritable bowel syndrome

The purpose of this study was to investigate thepotential of a computerized auscultation method forproviding an objective, quantitative measurecharacteristic of irritable bowel syndrome. Bowel sounds from irritable bowel patients and normalcontrols were digitized using an electronic stethoscope.Computerized analysis indicated that the character ofthe bowel sounds did not differ significantly between groups. However, the fasting sound-tosoundinterval was significantly different between groups(1931 ± 365 msec for normals and 452 ± 35msec for the irritable bowel group; P = 0.0001). Usingthe sound-to-sound interval as a test for irritable bowelsyndrome, the cutoff value of 640 msec resulted in asensitivity of 89%, and a specificity of 100%. Weconclude that computerized analysis of bowel sounds hasthe potential to be a noninvasive, quantitative,and objective test providing positive criteria in thediagnosis of irritable bowel syndrome.

Two-Dimensional Positional Mapping of Gastrointestinal Sounds in Control and Functional Bowel Syndrome Patients

Computerized auscultation of the abdomen provides a noninvasive and quantitative method to investigate gastrointestinal function. Two-dimensional mapping of bowel sound sites of origin, to the surface of the abdomen, was accomplished through simultaneous recording with three electronic stethoscopes. Control, irritable bowel syndrome, and nonulcer dyspepsia groups were studied. The predominant site of fasting sound production was the right lower quadrant in all except a subgroup of nonucler dyspepsia patients. The second most common site mapped to the area of the stomach. The region mapping to the small intestine was largely devoid of sound. The control group had a higher percentage of sounds in the 184- to 248-Hz range than the functional bowel patients (P < 0.001) for sounds mapping to the stomach region. We conclude that two-dimensional mapping may have the potential to allow for the meaningful and objective categorization of groups of functional bowel patients.

Enterotachogram analysis to distinguish irritable bowel syndrome from Crohn's disease.

Crohns disease is often initially misdiagnosed as irritable bowel syndrome. The goal of this research was to determine if computerized auscultation (fasting enterotachogram analysis) could have a role in distinguishing between these diagnoses. Patients with irritable bowel syndrome, Crohns disease, and a control group were enrolled in the study. The fasting sound-to-sound interval, standard deviation of the interval, sounds per minute, and percentage time involved with bowel sounds was determined by computerized enterotachogram analysis. The mean sound-to-sound interval for the Crohns group (1232 msecs) and the controls (1706 msecs) was significantly higher than the irritable bowel group (511 msecs, P < 0.0001). We conclude that Crohns is not characterized by a shortened interval. The high negative predictive value of the fasting enterotachogram for irritable bowel syndrome suggests that an interval greater than 740 msecs should trigger a search for an alternative diagnosis to irritable bowel. Crohns disease should be included in that differential.

A Clinical System For Digital Imaging Colposcopy

We have developed a prototype digital imaging colposcope system for use in clinical, research and teaching environments. A goal of this system is to aid in earlier detection of cervical pathology and to assist in more precise site directed biopsies. The system is expected to provide a valuable research and teaching tool, as well as a mechanism for including colposcopic images in proposed medical Picture Archiving and Communications Systems (PACS). The system consists of a charge coupled device (CCD) imager attached to the camera port of a conventional photocolposcope, a microcomputer host and a software package for processing of the resultant digital images. It is envisioned that this basic system could eventually be reconfigured to accommodate advantages to be derived from an integrated expert system. We discuss the hardware and software system, review some of the analysis algorithms used for this application and present preliminary results of clinical use of the system.

Use of a Computerized GI Sound Analysis System

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A Digital Optically Multiplexed Charge Coupled Device (CCD) Based Deoxyribonucleic Acid (DNA) Sequence Reader

We have developed a unique prototype solid state digital imaging system for use in the analysis of one dimensional deoxyribonucleic acid (DNA) sequencing gels. The system can be used to digitize, interpret and store DNA sequence information directly from an autoradiogram. The system consists of a two dimensional charge coupled device (CCD) imager, a multiplexing optical front end for reformatting of the gel image, a microcomputer host and a software package for reconstruction of the gel image and analysis of the DNA sequence.

Cervical surface shape recovery using digital imaging colposcopy

A common application of digital imaging colposcopy in cervical examinations is the measurement of lesion dimensions and areas. Typically this is done by interactively marking the region of interest on a cervix image, calculating the corresponding pixel dimensions and then scaling to the colposcope optics. Until now no one has suggested a solution to the effects of the cervical surface slant on these measurements. Away from the cervical os the surface slant is large and lesion dimensions there will be underestimated, possibly leading to a misinterpretation of the lesions progression. In this paper we discuss a noninvasive method for determining the surface geometry of the cervix using digital imaging colposcopy. The method is an application of shape-from-shading techniques used to determine the surface slant at all points in the cervix image. From the surface slant we can calculate area corrections to measurements made on the image. In our initial investigations we have applied this method to area measurements of circular regions drawn on spherical test targets. Our results indicate that we can obtain improvements in area measurement errors of factors between 3 and 6, resulting in relative errors of a few percent.

Role of color and spatial resolution in digital imaging colposcopy

We have developed a practical digital imaging colposcope for use in research on early detection of cancerous and pre-cancerous tissue in the cervix. Several copies of the system have now been used in a variety of clinical and research environments. Two issues of considerable interest which emerged early in our work involved the roles of color and spatial resolution as they applied to digital imaging colposcopy. In each instance these qualities potentially have a significant impact on the diagnostic efficacy of the system. In order to evaluate the role of these parameters we devised and conducted a receiver operating characteristic (ROC) evaluation of the system. It is apparent from these tests that a spatial resolution of 512 x 480 pixel with 7 or 8 bits of contrast is adequate for the task. The more interesting result arises from the study of the use of color in these examinations; it appears that in general, contrary to the widely held perception of the physicians involved, color apparently provides the clinician with little or no diagnostic information. Indeed, in some instances, access to color seemed to confuse the physician and resulted in an elevated rate of false positives. Results of the ROC tests are presented in this paper along with their implications for further development of this imaging modality.