Research On Three-dimensional Model Construction And Radiotherapy In Pineal Region

BackgroundPineal region locates deep and important neural structures, arterial and venous plexusin deep brain are concentrated in this region, therefore, the surgery in pineal region is quitechallenging. Being familiar with microscopic anatomy and adjacent relationship of pinealregion can not only reduce surgical mortality and morbidity, but also provide references foraccurate formulation and implementation of tumor radiotherapy plan in pineal regionclinically. It mainly relies on CT or MRI images to diagnose pineal region tumor currently,and then some auxiliary examinations, such as: patient’s symptoms, age and gender,cerebrospinal fluid. Both CT and MRI are sensitive to pineal region tumor and whichprovides a great convenience for treatment options. Meanwhile, in terms of this complexpineal region, current two-dimensional image cannot meet the clinical needs and there arefew studies in aspects of three-dimensional. This paper intends to reconstructthree-dimensional on pineal gland and adjacent structures that based on sectional anatomyand provide morphological basis for clinical diagnostic imaging and treatment of pinealregion disease.These low incidence pineal region tumors have complex pathological constitutions,according to WHO classification in2007, they can be divided into four categories: germcell tumors, pineal parenchymal tumors, neural epithelium tumors and tumors of othersources. Each category is divided into different histological subtypes, treatment andprognosis of different pathological types of tumors are quite different. Current treatmentsare mainly surgery, chemotherapy, radiotherapy and comprehensive treatment, someadvocate surgery as the preferred while some advocate radiotherapy first and thenreoperation. There is a big controversy on treatment and no consensus are reached bothhome and abroad, we focus on research and analysis imaging findings, clinicalmanifestations, tumor markers, treatment methods and pathology results of pineal region tumors.Purpose1. Human head structure is complicated, especially the pineal region, mutual positionalrelationship has great impact on organ function, not only it is imaging area that hard toanalyze, but also diagnostic and treatment for clinical disease in this area is a difficult point.Through anatomy of the fault plane in pineal region and research on3D reconstructionmodel, we can further familiarize and master anatomical structures of this region,relationship between pineal gland and surrounding structures, besides, we can alsoinvestigate potential impact of surrounding structures on direction and morphology oftumor growth in pineal region, and provide new ideas and theoretical guidance for radiationtherapy, surgical approach of clinically pineal region tumor as well.2. Use digital visual person (first Chinese man) data sets to do sectional anatomicalstudy on pineal gland and spatial relationship of its adjacent structures, and do3Ddimensional reconstruction with computer and virtual reality show to clarify thethree-dimensional shape,spatial location and adjacent relationship to each other ofimportant anatomical structures in this region. On this basis, combine modern imagingtechniques with stereotactic radiotherapy (SRT),3D dimensional conformal (3DCRT) andintensity modulated radiation therapy (IMRT) and apply it to the pineal region tumorradiotherapy to improve the accuracy of radiotherapy planning and implementation processand maximum protect normal tissue around the tumor, thereby, we can improve the controlrate of local tumors and reduce radiation complications.3. Investigation and analysis on treatment model (include surgery and radiationtherapy) and pathological type of pineal tumors of western region provide a basis forcontractions of cancer clinical pathway rationalization in pineal region.MaterialsContinuous cross-sectional images of the head (0.25mm thickness) in digital visualperson (first Chinese man) data sets; one10%formaldehyde fixed adult cadaver specimen;computer, Adobe photo shop CS4, Amira software; SIEMENS MAGNETON IMPACT2.0TMA Nuclear Magnetic Resonance (NMR).Informations of pineal region tumor treatment with more complete clinical dataadmitted to9top three hospitals in the past eight years, which include the choice of surgery and radiation therapy as well as treatments and results.Methods1．Using digitized visible human (first Chinese man) data sets, of which the continuoussection has the following advantages: layer thickness is thin(layer thickness of0.25mm),image after reconstructed is distinct, data is accurate, conduct a cross-sectional anatomyobservation on the pineal gland and adjacent structures, and extract relevant section imageinformation. We make MRI scan for the adult cadaver specimens fixed by10%formalinand get its sectional images of axial, coronal and sagittal three orientations. We alsoconduct control study of the CVH sectional images and typical MRI image in thecorresponding layers (all structures included in process from the pineal gland appear todisappear); extract the cross-sectional images with typical signs, and conduct controlledstudy for the anatomy structures of cross-sectional image.2. Based on the CVH data set, we use Amira software to make semiautomaticsegmentation and3D reconstruction to the structure of the skull base area, establish precisethree-dimensional visualization model of human brain’s pineal gland region, thus providemorphological basis for the precise formulation of the surgical approach and the radiationtherapy plan of the disease in pineal region.3. Retrospective analysis of the more complete tumor treatment data in pineal glandregion in the recent8years of the neurosurgery and radiotherapy in the top three hospitalsin western China (listed in appendix), focus on analysis of the selection of surgicaltreatment and radiation therapy, treatment methods, procedures and other treatments oftumor in pineal gland region.Results1. After comparing the CVH sectional images with MRI images in corresponding layer,we clearly observe the morphology and laws of the continuous section of fine structure inpineal gland region; compare the section imaging characteristics of the main structure inaxial, coronal and sagittal three directions, describe the typical Section morphology of themain structure in the two-dimensional layer and its adjacent relationship, and provideanatomical basis for the imaging studies of space-occupying lesions in the skull base area.2. Make segmentation and3D reconstruction to the section structure with Amirasoftware on computer; reconstruct the structures in three-dimension such as corpus callosum, the pineal gland, lateral ventricles, hippocampus and basal nuclei, thus the backof pineal gland is located in splenium of corpus callosum, the front of it is located in therear wall of the third ventricle, and the rear of it is located in the superior cerebellum. Thesevisualized reconstructed3D models clearly show the morphology and spatial relationship ofthe pineal gland and surrounding structures, and can be rotated and cut in any angle, alsocan be displayed separately, or in any combination, or displayed in whole.3. The survey have collected a total of219cases, in which there are58cases ofsurgical treatments, that52cases of total tumor resections,6cases of subtotal tumorresections, and in which there are2cases of operative deaths,4cases of peri-operativedeaths,9cases of postoperative coma or severe comas,2cases of disease deteriorated andgave up treatments;196cases of radiation therapy:99cases of radiotherapy after ventricle-peritoneal shunt and third ventriculostomy,58cases of direct radiotherapy alone,39casesof both surgical resection and radiation therapy. In radiation therapy, there are153cases ofstereotactic radiotherapies,43cases of radiotherapies with linear accelerator (in which thereare25cases of first diagnostic radiotherapies), in which there are21cases of conventionalfractionated full central irradiation radiotherapies.Conclusions1. CVH sectional images may well display the fine structure of the pineal gland regionbecause of its thin layer which is merely0.25mm, while normal layer of CT/MRI images isgenerally3~5mm. After comparison study combined with MRI images, we conclude thesectional imaging characteristics of pineal gland in axial, coronal and sagittal threedirections, thus we can deeply acknowledge the morphology and law of continuous thinsectional of the fine structure of in pineal gland region, which can not only provideanatomic basis for surgical neurological disease diagnosis, but also improve image confirmrate of small lesions in pineal gland region, and can reduce missed diagnosis andmisdiagnosis.2. The pineal gland and surrounding hypothalamus, hippocampus, lateral ventriclesand third ventricle, etc. reconstructed by Amira software are in clear structure, of which theconstruction model can more accurately reveal the adjacent relationship of the pineal glandwith surrounding structures, that the three-dimensional model reconstructed by3D not onlyhas obvious advantages in the study of the complex anatomy of pineal gland region, but also has significant value in the research on the relationship between the structure of theskull base area; what’s more, it can provide new means and new methods for clinicians toformulate pineal gland region tumor radiotherapy plans, design pineal gland region surgicalapproaches and simulate surgical operation on computer. Establishing visualizationanatomical models of the pineal gland not only provides a teaching platform for carryingout the digitized anatomy, but also provides stereoscopic morphological basis forcomputer-aided navigation surgical in pineal gland region and tumor radiotherapy in pinealgland region.3. Ventricle-peritoneal shunt/third ventriculostomy+radiotherapy is the mostcommon mode of the pineal gland region tumor therapy, which accounted for53.9%; thesecond is the mode of tumor resection+radiotherapy, which accounted for21.5%. Everyunit varies greatly in irradiation mode and radiation dose during radiation therapy, whichindicates the highly irregular in tumor therapy, and prompts that it is very necessary toestablish diagnosis norms of tumor in pineal gland region.