Laparoscopic spectral analysis of endometriosis.

Study Objective: To determine if lesions of endometriosis will preferentially absorb light of the blue spectrum thus enabling the detection of nonvisualized disease.

Design: Retrospective analysis (Canadian Task Force classification II-2).

Setting: University based teaching hospital.

Patients: Twenty-five women with pain suggestive of endometriosis.

Intervention: A noninvasive technique was employed to better visualize lesions of endometriosis at time of diagnostic laparoscopy.

Measurements And Main Results: A Storz PDD light source, which delivers a blue light at a specified frequency of 440 Hz, was used concurrently with full-spectrum white light. A Storz PDD laparoscope, which utilizes filters to detect the blue spectrum of light, was then coupled to the blue-light source. Lesions of endometriosis were compared using standard white light to that of blue light. The new lesions seen using blue light were sampled to confirm pathology. Using standard white light, black, red, and clear lesions were identified, and the borders of the lesions were marked. The same lesions were observed using the blue spectrum of light. The lesions absorbed blue light, but nonvisible endometriosis surrounding the classic lesions were also identified. Biopsies confirmed endometriosis in newly visible lesions.

Conclusion: Lesions of endometriosis preferentially absorb the blue-light spectrum. Laparoscopic spectral analysis enables visualization of previously nonvisible endometriosis and makes other visible lesions easier to identify.