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We report preliminary clinical testing of elastic-scattering spectroscopy for the detection of pathologies of the gastrointestinal tract. Tissue pathologies are detected and diagnosed using spectral measurements of elastically scattered light in an optical geometry that results in sensitivity to both the absorption and scattering properties of the tissue, over a wide range of wavelengths (300 to 750 nm). The system employs a small fiber optic probe, which is amenable to use with most endoscopes or catheters, or to direct surface examination, as well as interstitial needles. In this paper we report the results of preliminary clinical measurements on various organ sites of the gastrointestinal tract. In several instances the data indicate promise for this diagnostic method to distinguish malignant and dysplastic conditions from normal or other diagnoses.

Tissue spectroscopy for gastrointestinal diseases has made rapid strides in methodology and technology, with recent studies showing very promising results for the detection of pre-cancers and cancers. Laser-induced fluorescence spectroscopy, elastic scattering spectroscopy, and Raman spectroscopy have all shown favorable results in the diagnosis of malignancies and dysplasia in a number of small studies, both in vitro and in vivo. While technical limitations have been encountered with each of the techniques, significant advances have been made in the last year that may allow a highly sensitive and specific diagnosis to be generated within seconds, allowing directed or guided biopsies or therapy during a single procedure. Large multicenter trials will be necessary to demonstrate the efficacy, usefulness, and efficiency of these new tools.

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R ecent studies have emphasized the potential for severe reactions re lated to gastrointestinal contrast media [1,2]. We describe a case of toxic epi dermal necrolysis related to oral administration of diluted Gastrografin (diatrizoate meglumine and diatrizoate sodium; Bracco Diagnostics, Princeton, NJ) for abdominal CT. Case ReportThe patient was a 36-year-old man with a long-standing history of alcohol-induced pan creatitis. An episode of hemorrhagic pancreati tis occurring between August and October 1991 required multiple abdominal surgeries in cluding partial pancreatectomy, peripancreatic debridement, and fluid collection drainage.During that admission, three abdominal CT ex aminations were performed using both diluted oral Gastrografin and IV contrast media. The first two CT studies were performed using the nonionic contrast medium Isovue (iopamidol;Bracco Diagnostics), and the final study was performed using the ionic contrast mediumRenografin 60 (diatrizoate meglumine; Bracco Diagnostics). After this last CT study a tran sient skin rash and erythema developed.In April 1992, the patient was readmitted with bleeding gastric varices associated with vere persistent epigastric pain radiating into the back. ERCP showed diffuse ductal changes con sistent with chronic pancreatitis. Premedication with Solu-Medrol was used, and nonionic con trast medium (iopamidol) was used for the duc tal injection. No contrast reaction occurred from the ERCP. To evaluate for a possible pseudocyst, an abdominal CT study was then requested. We elected to perform the abdominal CF study with oral contrast medium (diluted Gastro grafin) only and to withhold IV contrast media. The patient did not receive steroid premedication for the abdominal CT scan.No pancreatic mass or pseudocyst was ev ident on the abdominal CT study. A metallic coil in the splenic artery from prior embo lization therapy was noted.Approximately 30 mm after ingestion of the oral contrast medium, the patient complained of diffusepruritus,and patchyerythemawas noted on the thighs, flanks, and upper back along with minimal conjunctival injection. We Pharmacia and Upjohn) to be taken orally that evening and was instructed to return on the next day for a follow-up examination. The next day, pruritus, erythema, and con junctival injection had returned and were more pronounced than previously. The patient was