Comparative Study Of Imaging And Pathology Of Intracranial Tumor

Part 1 A statistic analysis of 1179 cases with intracranial tumorObjective: To study the occurrence regularity of intracranial tumors,in order to improve the accuracy of preoperative diagnosis.Methods : According to the age and sex of patients, and the histopathological types, a retrospective analysis of 1179 patients with intracranial tumor verified by postoperative pathological examination was studied. Comparing to literatures to analyse the occurrence regularity of of 1179 cases with intracranial tumors based on the 2007 WHO classification of tumors of the central nervous system.Results: The age of patients with high incidence was 40-60 years old, and the number of female patients was slightly more than the male. The histopathological types of the tumor were meningiomas(30.28%),neurocytoma(29.7%), pituitary adenoma(20.78%), neurinoma(10.77%), metastatic tumor(2.97%), craniopharyngioma(2.37%), lymphomas(1.44%), chordoma(0.76%), germ cell tumor(0.68%) and etc ( 0.25% ) . The incidence of neurocytoma is slightly lower than meningiomas, formerly reported that the former is higher than the latter. The common histopathological types of the child group were astrocytic tumors( 30% ) , ependymoma (13.33%), craniopharyngioma(13.33%) and medulloblastoma(8.33%). The common histopathological types of the older age-group were meningioma(31.78%), astrocytic tumors (22.03%), pituitary tumor(14.83%) and neurinoma(10.17%).Conclusion: There is a certain regularity about sex and age of patients and histopathological types of intracranial tumors. With the development of imaging techniques, the incidence rate of intracranial tumor increased these years. Part 2 Misdiagnostic Analysis of CT and MRI for Intracranial TumorObjective: To analyze the causes of misdiagnosis of CT and MRI for intracranial tumor and to improve the diagnostic accuracy.Methods: A retrospective analysis of CT and MRI imaging of 56 cases with intracranial tumor verified by postoperative pathological examination was studied and the causes of misdiagnosis were summarized. We observed each patient'images repeatedly and summarized the misdiagnostic reasons from the following aspects:①mispositioning ;②"typical signs"for misdiagnosis;③atypical signs;④rare diseases misdiagnosis;⑤one-sided thinking misdiagnosis。Results: The total misdiagnostic rate of CT and MRI is 14.7 %. There are 26 benign tumors, 28 malignant tumors and 2 boderline tumors. The constituent ratio respectively is 46.4%, 50%, 3.6%. The most common pathologic type is astrocytic tumors in all misdiagnostic tumors. The higher misdiagnostic rate tumors are lymphomas, primitive neuroectodermal tumuour, metastatic tumours and ependymoma. The misdiagnostic rate respectively is 71.43%,60%,38.46%,33.33%. 27 cases misdiagnosis are induced by mispositioning ; 8 cases misdiagnosis are induced by"typical signs"; 22 cases of misdiagnosis are caused by atypical signs ; 16 cases misdiagnosis are due to rare diseases ; 12 times misdiagnostic reasons are one-sided thinking.Conclusion: It is necessary to summarize misdiagnosed cases and avoid unnecessary misdiagnosis. We must narrow the range of differential diagnosis of difficult cases.Part 3 MR imaging diagnosis of primitive neuroectodermal tumour in adultsObjective: To study the MRI features of primitive neuroectodermal tumor (PNET) in adults and improve the accuracy of preoperative diagnosis.Methods: MR images were analyzed retrospectively in 5 adult patients with PNETs proved by operation and pathology.Results: The tumors showed large, oval , lobulated and with significant space occupying. There were obvious peritumoral edema in 1 case of PNET, mild peritumoral edema in 1 case, and no edema in 3 cases of PNET. PNET demonstrated slight long T1 and slight long T2 signals. The solid part of the tumors were obvious homogeneously or annular enhanced after injection of gadolinium. There were always cystic ,necrotic areas and intratumoral haemorrhage in the tumors. 2 cases with intracranial metastases and 2 cases with pulmonary metastases were found.Conclusion: There are certain characteristic MR findings of PNET. MRI is helpful to diagnosis and treatment planning.Part 4 MR features of primary central nervous system lymphomaObjective: To study the MRI features of primary central nervous system lymphoma ( PCNSL).Methods: A retrospective analysis was done in 7 cases of PCNSL in terms of its MRI features.Results: Single lesions were found in 4 cases and multiple ones in 3 cases.Among the 11 lesions,4 located in frontal lobe,2 in parietal lobe,temporal lobe , cerebellar hemisphere and 1 in corpus callosum. MR images revealed the tumors to be hyper- or slightly hypo-intense on T1 weighted images and hyper- or slightly hyper-intese on T2 weighted images, slightly hyper or hyper-intense on fluid attenuated inversion recovery ( FLAIR) , and hyper-intense on diffusion weighted imaging (DWI) . Most lesions presented obvious and homogeneous enhancement ."Incision sign"was found in 2 lesions and"angular sign"in 1 lesion. 3 lesions showed abnormal enhancement of the mater after gadolinium injection. There were 8 lesions with slightly or moderately edema and 3 with heavy edema.Conclusion: The MRI performance of primary central nervous system lymphoma has certain characteristic value,but it is difficult to diagnose the uncharacteristic ones.