Initial Experience with Diffusion-weighted Imaging to Predict the Tumor Consistency and Surgical Success in Solid Growth Hormone Producing Pituitary Macroadenomas.

BACKGROUND: Tumor consistency is an important factor impeding transsphenoidal resection of some pituitary macroadenomas. Preoperative prediction of the tumor consistency may help neurosurgeons in preparing the patients for other therapeutic options after a subtotally resected growth hormone (GH)-producing macroadenoma. We present the preliminary results of our study about the application of the preoperative diffusion-weighted (DW) magnetic resonance imaging (MRI) to predict the consistency and resection rate of GH-producing pituitary macroadenomas. MATERIALS AND METHODS: Sixteen primary patients with solid GH-producing pituitary macroadenomas were enrolled. Hormonal assays as well as standard and DW-MRI were obtained before surgery. All the patients were operated via an endoscopic transsphenoidal approach. The intraoperative tumor consistencies (suctionable versus nonsuctionable) were documented. The samples were stained for measurement of the collagen content (low, moderate, and high). Postoperative hormonal study and MRI were performed after 8 weeks to evaluate the resection ratio and the hormonal remission. RESULTS: On DW images, the tumor diffusion was enhanced (free) in four, moderate in ten, and restricted in two patients. The tumor was suctionable in 14 cases; gross total resection and hormonal remission were achieved in 12/14 of these. All the 14 suctionable tumors had moderate to enhanced diffusion on DW imaging (DWI). The two patients with a nonsuctionable fibrous tumor had a restricted diffusion in DWI. These were the only ones to have high collagen content in the histopathologic study. CONCLUSION: DWI could help identify the fibrous nonsuctionable GH-producing adenomas from the others.

Predictive value of diffusion-weighted MRI for tumor consistency and resection rate of nonfunctional pituitary macroadenomas.

BACKGROUNDS: Firm tumor consistency is one of the most important factors that impede sufficient removal of pituitary macroademoas via a transsphenoidal approach. The utility of diffusion-weighted (DW) magnetic resonance imaging (MRI) in predicting the tumor consistency and successfulness of transsphenoidal resection was evaluated in this study. METHODS: Thirty consecutive primary cases of nonfunctional pituitary macroadenomas were prospectively enrolled. Conventional and DW MRI were done for all the patients and the apparent diffusion coefficient (ADC) values and the signal intensity of the solid tumor were determined. Intraoperative report of tumor consistency, the degree of fibrosis and percentage of collagen content were documented. The 8 weeks postoperative MRI was used for calculation of the tumor resection rate. RESULTS: The tumor consistency was soft in 10 patients (33.3 %), intermediate in 14 patients (46.7 %) and hard in 6 patients (20 %). The mean collagen content percentage was 10, 23.5 and 66 % (p = 0.009) and the average resection rate was 75, 43 39 % in the three groups respectively (p = 0.001). The mean ADC value was not significantly correlated with the tumor consistency and resection rate. Tumors with isointense to hyperintense signal on DW MRI were more commonly removable by suction and had higher resection rates than those with hypointense signals (p = 0.019). For ADC values within the range of 600-740 × 10(-3) mm(2)/s, a residual volume larger than 20 % of the tumor was more likely. CONCLUSIONS: DW MRI was useful to predict the tumor consistency, collagen content and the chance of removal of pituitary macroadenomas through endoscopic transsphenoidal surgery, and is recommended in the preoperative patient evaluation.

Intrasphenoidal Meningo-encephalocele: Report of two rare cases and review of literature.

BACKGROUND: Transsphenoidal encephaloceles represent a rare clinical entity with wide range of symptoms in adult. Such lesions require accurate diagnosis and surgical treatment. The incidence of congenital encephalocele is very low occurring in approximately 1 in 3000-5000 live births. Even though 63 similar cases have been reported in the literature not all of them have been discussed completely. Due to the rare occurrence of these lesions, we will focus on the main clues in the diagnosis and management of such lesions, which are challenging. CASE DESCRIPTION: We intend to present our experience with two cases of trans-sphenoidal meningoencephalocels, one located medially and the other herniating through the Sternberg's canal. The younger was 17 and the elder was 47 years old and both of them presented with cerebrospinal fluid (CSF) leakage. Both patients were treated successfully using pure endoscopic endonasal approach. CONCLUSION: Ideal surgical approach for such patients is still not clear due to lack of adequate experience in the literature, it is suggested that full preoperative imaging studies might lead the surgeons to undertake minimally invasive skull base approaches in similar patients.