Application Of Imaging Postprocessing In Intranasal Endoscopic Skull Base Surgery

ForewordBecause of a narrow operating space and vision limitation, endoscopic skull base surgery requiring preoperative imaging data to fully understand. The method of imaging processing technology nowaday is increasingly diverse and complete, but it is limited in Image section of hospital, and is not flexible enough to observe. So that it can not fully meet the need for surgery sometimes. Intraoperative navigation technology is safe and accurate, but it is too expensive for many of otolaryngological departments in our country. Post-processing operated by the ENT surgeon personally can improve the image, and can run on portable devices which been brought to the operating room, and that may help improve the therapeutic effect and security of surgery.Part1The diagnostic value of the multi-planar reconstruction and maximum intensity projection in nose and skull base lesionsPurpose Study the ablity to reflect the skull base tumor and nasal lesions of the MPR and sMIP images conducted by otolaryngologists.Methods Study on21groups sinus or brain preopration CT images of17patients who underwent endoscopic sinus and skull base surgery during August2008to June2013in our department.2senior otolaryngologist, who was not involved in the operations, reading the original horizontal position images, multiplanar reconstruction images, and MPR with sMIP images successively and respectively, and to grade the image base on the display effect of tumor character, contour, relationship of tumor and blood vessels, bone, nerve tissue (including the brain). Charater results were compared with the pathological reports in hospital, other evaluation criteria according to the grade:refer to some literature data, the display effects were divided into three levels:level0-unable to determine the relationship between lesion and targeted tissues, score0; level1-can be inferred or partially observed the relationship between lesion and targeted tissues, but not clear, score1; level2-can clearly determine the relationship between lesion and targeted tissues, score2. Surgeons should draw the general outline of diseases, indicate relationship between tumor and a surrounding tissue (specific sources and contain, extrusion, erosion defects, separate), all inaccurate results calculated as0points to ensure objective of evaluation. The consistency between pathological reports and the results of the tumors’character were analysed with Kappa test; the others level data were analysed with the Wilcoxon paired rank sum test.Results (1) Based on two physicians’ judgments, consistency with pathological findings may be higher after sMIP and MPR than just use original images, but paired chi-square test was no significant difference;(2) the outlines of the mass base on observation of MPR image were clear and more complete than original data, but using sMIP could not be further improved;(3) compared to the original images, images with MPR has the advantage in showing the relationship between bone and mass;(4) compared to MPR images, images with sMIP has the advantage in showing the relationship between bone and vessel (5) For the relationship between the tumor and the nerve tissue,MPR did not show improvement of identification.Part2Comparison effects of the dynamic multiplanar reconstruction and the multiplanar reconstruction screenshot in the PACSObjective To compare the image of two observe methods:the surgeon observe dynamic MPR, and MPR screenshots riginal in PACS system terminal, to find out whether the former than is more conducive to observe contours and bone lesions.Methods Study on18groups sinus or brain preopration CT images of17patients who underwent endoscopic sinus and skull base surgery during June2011to February2014in our department. Inclusion and exclusion criteria of cases and image quality were same with part2. Images were reconstruction and observation by2senior otolaryngologists, who were not involved in the operation. Images were read for2times:Firstly, read the images on PACS workstation terminal (including the uploaded screenshots of MPR slected by radiologists and horizontal original scanned images); secoundly, read the processing results of MPR which conducted by otolaryngologist with osiriX in laptop. Evaluation including the contours of lesions, relationships between lesions and bone, evaluation criteria was in the same way as part2of the study.Results one surgeon scored the contour display quality as22,29and the bone around lesions as21,29after two observations, rank test showed a significant difference between two scores; another surgeon scored as18,28and the bone around lesions as23,32after two observations, rank sum test also showed a significant difference.Part3The application of different post-processing technique in diagnosing of complicated casesPurpose Try to use the postprosessing of imaging to predict important anatomical structure of complicated cases preoperative and design surgical approach, to show the significant of individual and multiple processing.Methods Pocessed CT and MRI preoprate images of7patients who underwent endoscopic sinus and skull base surgery during the August2010to February2014in our department. Useing a combination of5technique of multi-planar reconstruction, thin-slab maximum intensity projection, volume rendering, image segmentation and virtual endoscopy.Results All reconstructed images were shape, meet the need of surgeon and played a meaningful role during or before endonasal endoscopic skull base surgeries. MPR could be used as the basic diagnostic method in all cases, and is especially suitable for the diagnosis of undetectable leakage position of cerebrospinal fluid rhinorrhea; sMIP could correct the fuzzy defects of the original scanned image which less than lmm, and more importantly it could enhance the shape of major blood vessels; VR can show the overall and visual observation of craniofacial bone and skull base, it helps to detect disease quick and timely sometimes; image segmentation were conducive to show the relationship between the tumor and surrounding tissue; virtual endoscopy could be use to observe parts of intranasal and sinus which endoscopic could not observed. It can help surgeon be familiar with the lesion before surgery.