PubMed · 1054774
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W B Norment. 1975. Hysteroscopy.. https://pubmed.ncbi.nlm.nih.gov/1054774/
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A miniaturized sensor head for endoscopic measurements based on digital holography is described. The system was developed to measure the shape and the three-dimensional deformation of objects located at places to which there is no access by common measurement systems. A miniaturized optical sensor, including a complete digital holographic interferometer with a CCD camera, is placed at the end of a flexible endoscope. The diameter of the head is smaller than 10 mm. The system enables interferometric measurements to be made at speeds of as many as five reconstructions per second, and it can be used outside the laboratory under normal environmental conditions. Shape measurements are performed with two wavelengths for contouring, and the deformation is measured by digital holographic interferometry. To obtain full three-dimensional data in displacement measurements we illuminate the object sequentially from three different illumination directions. To increase the lateral resolution we use temporal phase shifting.
BACKGROUND: There are several CAS-systems in use in modern endonasal sinus surgery. The VectorVision Compact is the first optoelectrical system especially designed for such surgery. This paper investigates its reliability and practicability. PATIENTS AND METHODS: The system was used for intraoperative navigation in 60 patients suffering from chronic rhinosinusitis. The accuracy was measured by visual estimation and compared with other navigated systems. RESULTS: The accuracy was 1.9 mm which is comparable to other systems on the market. Navigation was successful and reliable in 83.3% of the patients. Problems occurred mainly due to loss of sight of the referencing balls and when using other surgical instruments. CONCLUSION: The VectorVision Compact was adequate for endonasal sinus surgery. Further improvements incorporating various surgical instruments should broaden its clinical usefulness.
BACKGROUND: The availability of an electronic radial scanning echoendoscope has facilitated the clinical use of tissue harmonic imaging. This study compares the quality of US images acquired by tissue harmonic imaging during electronic radial scanning EUS to those acquired by fundamental imaging. METHODS: Electronic radial scanning EUS was performed in 108 patients with pancreatic lesions (58 cystic, 50 solid). US images acquired by fundamental imaging at a frequency of 7.5 MHz were compared with those acquired by tissue harmonic imaging by using transmitting and receiving frequencies of, respectively, 4.0 and 8.0 MHz at the same scanning plane. Cystic lesions were evaluated for boundary/septum and nodules, and solid lesions, for boundary and internal structure. US images acquired by tissue harmonic imaging and fundamental imaging during electronic radial scanning EUS were compared, by using a Likert scale for the respective evaluation criteria, by two independent endoscopists. OBSERVATIONS: For cystic lesions, tissue harmonic images were significantly clearer than fundamental images for visualizing boundary and septum (p < 0.0001, both reviewers) and nodules (p = 0.0003, Reviewer 1; p = 0.0007, Reviewer 2). For solid lesions, tissue harmonic images were significantly clearer than fundamental images for visualizing boundary (p = 0.0003, Reviewer 1; p < 0.0001, Reviewer 2) and internal structures (p = 0.0003, Reviewer 1; p = 0.0009, Reviewer 2). CONCLUSIONS: US images acquired by tissue harmonic imaging appear to be clearer compared with those acquired by fundamental imaging.