Prediction Of The Consistency Of Pituitary Adenoma:a Comparative Study On Diffusion-Weighted Imaging And Pathological Results

Part Ⅰ:Diffusion-Weighted Imaging of Sellar Region:A Comparison Study of BLADE sequence and Single-Shot Echo Planar Imaging sequencePurpose:The purpose of this study is to compare BLADE Diffusion-Weighted Imaging (DWI) with single-shot Echo Planar Imaging (EPI) DWI on the aspects of feasibility of imaging sellar region and its own image quality.Methods:A total of 55 patients with suspected lesions in the sellar region (52 showed pituitary lesions in MRI images) were included in this intra-individual study. All exams were performed at 3. 0T with BLADE DWI sequence and a standard single-shot EP-DWI sequence. Phantom measurements were performed to measure the objective signal-to-noise ratio (SNR). Two radiologists rated the image quality according to the visualization of internal carotid arteries, optic chiasm, pituitary stalk, pituitary gland and lesion, the overall image quality as well. Two radiologist measured lesions’ sizes for detecting their relationship with the image score.Results:The SNR in BLADE DWI sequence showed no significance compared to the one of single-shot EPI sequence (P>0.05). All the assessing part got higher scores in BLADE DWI images than single-shot EP-DWI images, especially the visualization of internal carotid arteries, overall image quality. There was a weak relation between minimal lesion diameter and the score concerning lesion visualization. According to the approximation formulas obtained by linear regression, the minimal diameter of lesion whose score reached 2 was 12mm in BLADE DWI images while the one is 31mm in single-shot EP-DWI images.Part Ⅱ:The relationship between tumor consistency and MRI signal intensityPurpose:The consistency of pituitary adenoma plays an important role in surgery decision and evaluation on prognosis. It will definitely bring great benefits if clinicians can judge the tumor’s consistency before surgery. This part of our research is to acquire signal intensity in different MRI sequences and analyze the relationship between tumor consistency and MRI signal intensity according to operation findings.Methods:A total of 34 patients with pituitary adenomas were enrolled in this study. They showed typical clinical manifestations, underwent surgical treatments and got pathological diagnosis as pituitary adenomas in our hospital. All radiological exams were performed at 3. OT with T1-weighted cornary, T2-weighted coranary, constrasted T1-weighted cornary and BLADE DWI scanings. The evaluation of tumor’s consistency and pathological and immunohistochemical results were collected respectively during and after the surgery. The consistency of pituitary adenomas was devided into 2 groups as soft and hard one.Results:There was no significant correlation of tumor’s consistency with patent’s age, gender, age of onset, invasiveness of pituitary adenomas, the size of tumor or tumor’s function. MRI parameters including T1 SI ratio (tumor to grey matter), T2 SI ratio (tumor to white matter), contrasted T1 SI ratio (tumor to grey matter) and ADC ratio (tumor to brainstem) showed no significant relation with consistency, P>0.05. ROC curve was made concerning MRI signals and consistency evaluation and ADC ratio elucidated certain diagnostic value, whose AUC was 0.774 along with a cutoff by 1.077 (sensitivity 80%, specificity 62.7%). With regard to tumor s function, T2 SI ratio (tumor to white matter) revealed a close relationship with it, P=0.031<0.05. AUC under ROC curve was 0.775 and the cutoff value was 1.990 which indicated that if rT2>1.990, the pituitary adenoma was more likely to be non-function one.Part III:The relationship between tumor’s consistency and collagen contentsPurpose:Some research found tumor s consistency was relevant to its collagen content. This part of our study is to explore the relationship between collagen content and tumo’s consistency or the MRI signal intensity before operation and to find out the diversity of collagen in different types of pituitary adenomasMethods:In this part, a total of 34 patients with pituitary adenomas were enrolled. They showed typical clinical manifestations, underwent surgical treatments and got pathological diagnosis as pituitary adenomas in our hospital. All radiological exams were performed at 3. OT with T1-weighted coronary, T2-weighted coronary, contrasted T1-weighted coronary and BLADE DWI scanning. The evaluation of tumor s consistency was collected during the surgery. The collagen content in pathological specimens was analyzed qualitatively and quantitatively under hematoxylin-eosin staining, Masson trichrome staining respectively.Results:Collagen content showed significant difference both qualitatively and quantitatively in soft and hard groups, while the percentage of collagen in soft pituitary adenoma is 7.27+1.18%and 17.72+2.00% in hard adenomas, P=0.0013. AUC under ROC curve was 0.8966 and the cutoff value was 15.39%(sensitivity 89.66%, specificity 80%) which could be used to evaluate tumor s consistency. Regarding MRI signals, ADC ratio (tumor to brainstem) got close relationship with collagen contents. Collagen content in tumors were divided into 3 groups qualitatively by H. E. staining as (+), (++) and (+++), while ADC ratio (rADC) was 1.5172,1.0998,1.0431, revealing significant difference with P=0.016. This result indicated that rADC was getting lower when collagen content grew. But the line regression showed no relationship between rADC value and percentage of collagen in the tumors, R2=0.2175. Other MRI signal intensities including rTl, rT2 and contrasted rTl were not relevant to collagen content, either were clinical data such as age, gender, course, size of tumors, invasiveness of tumors, size of tumors or tumor’s function.