Preliminary Clinical Study Of 1H-MRS And T1ρWI In Pituitary Macroadenoma

ObjectiveSuprasellar area was an important region in neurosurgical practice due to its proximity to vital structures such as pituitary gland, hypothalamus, and the circle of Willis. A variety of different pathologic processes can occur in this area, namely, neoplasms, developmental pathologies, vascular pathologies, inflammation, and infection, of which neoplasms were the most common. Selecting the ideal treatment for suprasellar tumors depended on the pathology of the tumor. Pituitary adenoma was the most common of the lesions involving both intrasellar and suprasellar regions. Technological developments in CT and MR, including the addition of thinner sections and newer contrast enhancement methods had further refined pituitary imaging. It had high accuracy for CT and MR in diagnosis of pituitary adenoma. There were numerous cases where CT and MRI fail to predict histology. As we wanted to understand pituitary macroadenoma comprehensively, We tailored our series to pituitary macroadenomas by analyzing retrospectively the clinical and radiological features of patients who underwent surgery at the Nanfang Hospital.Hyrogen magnetic resonance spectroscopy (H-MRS) was a noninvasive technique that allowed in vivo measurement of certain tissue metabolites and characterized pathophysiological processes. The aim of this study was to explore the MRS characteristics of pituitary macroadenoma.T1ρ contrast was considered to reflect differences in cell density by its specificity to water spin dynamics such as chemical exchange of protons between water associated with macromolecules and free water. The present study was designed to evaluate if Tip could be different in pituitary macroadenoma, craniopharyngiomas,and meningioma and determine if there was a correlation between T1 p and ADC.Materials and methods1.Subjects(1)Reviewed and summarized the pituitary adenocarcinoma’s clinical and conventional MRI features of patients who underwent surgery at the Nanfang Hospital between September 1,2012 and September 1,2014. (2) refer to the result of first part, we took out the patient might be pituitary macroadenoma with diameters of more than 15mm.15 patients with glioma whose gender and age were matched with pituitary macroadenoma were collected to be the control group. After obtaining informed consent, these patients were performed by 1H-MRS examination. (3) When a sellar/suprasellar tumor was considered in the conventional MRI examination, the patient was underwent T1pWI and DWI examination.2. Conventional MRI examinationsAll examinations were performed on Philips Achieva 3.0T MRI scanner, using standard head coil as emission and reception coil. All the patients underwent conventional axial view T1WI, T2WI, fluid attenuated inversion recovery (FLAIR), sagittal view T1WI and Coronal view T2WI. Axial, sagittal and coronal view T1WI were obtained after gadopentetate dimeglumine administration. The MRI images were analyzed and diagnosed by two senior radiologists with the principle of double-blind.3.1H-MRS examinationsAll examinations were performed on Philips Achieva 3.0T MRI scanner. 1H-MRS was acquired using a point-resolved spectroscopy sequence (PRESS) with single voxel in pituitary macroadenoma (TR=2000ms, TE=36ms) and multi voxel in glioma (TR=2000ms, TE= 144ms). The location of region of interest (ROI) was based on axial view, combined with coronal view and sagittal view. The volume of region of ROI of lesion were 20 mm×20 mm×20mm (NSA=128) and 15 mm×15 mm× 15 mm (NSA= 256). Late-stage processing of spectrum was performed on Spectroview Spectrum Software. Areas below the peak of N-acetyl aspartate (NAA), Choline (Cho) and Creatine (Cr) were calculated by the integrity method, each value representing concentration of each substance. The ratios of Cr/Cho and NAA/Cho were calculated.4.T1ρWI and DWIAll examinations were performed on Philips Achieva 3.0T MRI scanner, using standard head coil as emission and reception coil.3D-SSFP imaging readout was used. T1ρ were assessed using TR=4.85ms, TE=2.39ms, flip angle=50°, FOV= 22cm2, 2562 matrix, and slice thickness= 3 mm. Thus, the digital pixel area was 0.49 mm2, The spin lock frequency was 500 Hz.Total spin lock times (TSL) of 0,20,40,60,80, and 100 ms were used. T1ρ maps were co-registered and subtracted to provide a map of the voxel-wise differences. DWI was acquired echo planar imaging, b value of 0 and 1000 s/mm2 were used. To determine the T1ρ values and ADC values, the ROIs were placed in the central and solid part of the tumor; avoiding any cystic or calcified areas,they are defined anatomically.5.HistopathologyIn all case surgery was done within two weeks after MRI examination. Hematoxylin and eosin staining was used routinely, as well as appropriate immunohistochemistry.6. Statistical analysisSPSS 20.0 software package was applied to statistical analysis in this study. The measurement data was recorded as (mean ± standard deviation). The statistically significant differences was set at P<0.05.(1). Independent-Sample T Test was performed to compare age between male and female.The effects of gender with different hormone-secreting type in different groups were analyzed with RxC Chi-Square Test.(2). Independent-Sample T Test was performed to compare metabolic ratios of pituitary macroadenoma’s and glioma’s.(3). Tip value of pituitary macroadenoma, craniopharyngiomas,and meningioma were compared with One-Way ANOVA analysis. Used LSD method for Post hoc Multipe comparisons and used Dunnett’s method in the case of heterogeneity of variance.Bivariate Correlations was performed to analyze the relationship between Tip value and ADC value of pituitary macroadenoma, craniopharyngiomas, and meningioma.Result:1. A total of 119 cases of patients (60 males and 59 females, male to female ratio=1:1, mean age=47.24±13.52year), met the requirements from 2012,09 to 2014, 09,40-60 years old was the most common. There was no statistically significant difference of different functional types of pituitary macroadenoma in different genders of patients(X2=9.845, v=6, P= 0.131). There was no statistically significant difference between the age and gender of patients with pituitary macroadenoma (P=0.98). Location and type of the tumor:90 cases of common type,21 cases of cystic type,8 cases of skull base type. Most tumors showed as 8-shaped. The signs of small vesicular signal intensity on T2WI in the solid areas of pituitary macroadenoma, forward growth of the tumor using anterior cranial fossa as a reference, and cystic lesions with thick wall violating the cavernous sinus could provide some clues for the differential diagnosis of pituitary macroadenoma on MRI.2.Cho, NAA, Cr, Glx, and Lip could be detected in the single voxel MRS in the group of pituitary macroadenoma.There were significant differences in the ratios of Cr/Cho-. NAA/Cho between pituitary macroadenoma and glioma.3.The T1ρ value of craniopharyngiomas was significant higher than pituitary macroadenoma and meningioma. However, T1ρ values showed no significant differences between pituitary macroadenoma and meningioma. There was a positive correlation between T1ρ value and ADC value.Conclusion:1. Pituitary adenoma was mostly diagnosed in forth to sixth decade. The female/male ratio was 1:1. There was no statistically significant difference between the age and gender of patients with pituitary macroadenoma. According to biological behavior,pituitary macroadenoma may divided into common type, cystic type, skull base type and ectopic type. The signs of small vesicular signal intensity on T2WI in the solid areas of pituitary macroadenoma, forward growth of the tumor using anterior cranial fossa as a reference, and cystic lesions with thick wall violating the cavernous sinus could provide some clues for the differential diagnosis of pituitary macroadenoma on MRI.2.The metabolins of pituitary macroadenoma included Cho, Cr,NAA, Glx, and Lip peak, and cho peak was usually the main one, while NAA and Cr peaks maybe influenced by partial volume effect. Now, the occurrence of the Glx peak infered to the meningeoma, but it maybe found in the pituitary macroadenoma and more cases should be done to identify this diagnosis. Lip peak may infered to hemorrhage and necrosis, but if just found high signals on T2WI and without this peak, it maybe just infered the acinar cells of the tumor.3. T1ρ contrast was considered to reflect differences in cell density by its specificity to water spin dynamics such as chemical exchange of protons between water associated with macromolecules and free water. The T1ρ value of was significant higher than pituitary macroadenoma and meningioma. Cell density of craniopharyngiomas was much lower than pituitary macroadenoma’s and meningioma’s, this identified with the solid part of craniopharyngiomas was constituted by keratin. There was a positive correlation between T1ρ value and ADC value,it may refered that diffusion motions participated in T1ρ contrast.