The findings at magnetic resonance (MR) imaging in a group of 36 pathologically verified supratentorial gliomas were analyzed and compared with the biopsy diagnoses (a) to determine whether MR imaging could be used to classify astrocytic-series tumors into a three-tiered system of low-grade astrocytoma, anaplastic astrocytoma, and glioblastoma multiforme; and (b) to evaluate MR imaging features that may aid in this classification. The MR characteristics evaluated were crossing of the midline, edema, tumor signal heterogeneity, hemorrhage, border definition, cyst formation or necrosis, and mass effect. The statistically significant MR characteristics (positive predictors) were mass effect (P = .0000) and cyst formation or necrosis (P = .0512). The MR accuracy rate approached that of neuropathologic diagnosis, which is subject to sampling errors. MR imaging may serve as an adjunct in case management when the clinical course and MR findings appear to be at odds with the neuropathologic diagnosis.

No abstract

Study Design-Correlation of locations of sacral insufficiency fractures are made to regions of stress depicted by finite element analysis derived from biomechanical models of patient activities.Objective-Sacral insufficiency fractures occur at consistent locations. It was postulated that sacral anatomy and sites of stress within the sacrum with routine activities in the setting of osteoporosis are foundations for determining patterns for the majority of sacral insufficiency fractures. Summary of Background Data-The predominant vertical components of sacral insufficiency fractures most frequently occur bilaterally through the alar regions of the sacrum which are the thickest and most robust appearing portions of the sacrum instead of subjacent to the central sacrum which bears the downward force of the spine.Methods-First, the exact locations of 108 cases of sacral insufficiency fractures were catalogued and compared to sacral anatomy. Second, different routine activities were simulated by pelvic models from CT scans of the pelvis and finite element analysis. Analyses were done to correlate sites of stress with activities within the sacrum and pelvis compared to patterns of sacral insufficiency fractures from 108 cases.Results-The sites of stress depicted by the finite element analysis walking model strongly correlated with identical locations for most sacral and pelvic insufficiency fractures. Consistent patterns of sacral insufficiency fractures emerged from the 108 cases and a biomechanical classification system is introduced. Additionally, alteration of walking mechanics and asymmetric sacral stress may alter the pattern of sacral insufficiency fractures noted with hip pathology (p=.002).Conclusions-Locations of sacral insufficiency fractures are nearly congruous with stress depicted by walking biomechanical models. Knowledge of stress locations with activities, cortical bone transmission of stress, usual fracture patterns, intensity of sacral stress with different activities, and modifiers of walking mechanics may aid medical management, interventional, or surgical efforts. NIH Public AccessAuthor Manuscript Spine (Phila Pa 1976). Author manuscript; available in PMC 2009 July 13. Published in final edited form as:Spine (Phila Pa 1976 Key Points• Identify the exact locations of sacral insufficiency fractures from large a consecutive series of cases by MRI and/or CT anatomical imaging methods.• Biomechanical model simulations to determine locations of stress within the sacrum with patient activities determined by finite element analysis.• Match clinical locations of sacral insufficiency fractures and sacral stress with activities as identified by the biomechanical models.• Sacral insufficiency fracture biomechanical classification system is introduced.• Knowledge of sacral stress locations with activities, cortical bone transmission of stress, usual sacral insufficiency fracture patterns, intensity of sacral stress with different activities, and modifiers of walking mechanics may aid medical, interve...

SUMMARY:We report the imaging features of 4 cases of patients with papillary tumor of the pineal region, a tumor newly recognized in the 2007 World Health Organization "Classification of Tumors of the Nervous System." In each case, the tumor was intrinsically hyperintense on T1-weighted images with a characteristic location in the posterior commissure or pineal region. The pathologic hallmarks of the tumor are discussed, including a possible explanation for the MR imaging characteristics in our cases. P rimary papillary tumors of the central nervous system and particularly the pineal region are rare. Papillary tumor of the pineal region (PTPR) is a recently described neoplasm that has been formally recognized in the 2007 World Health Organization (WHO) "Classification of Tumors of the Nervous System."1 Histologic features and immunohistochemical staining distinguish this type of papillary tumor from other papillary-like tumors that occur in the region. [2][3][4][5][6][7] It is postulated that the masses arise from the specialized ependymocytes of the subcommissural organ located in the lining of the posterior commissure. 4 There are documented cases in the neuropathology and neurosurgery literature but limited descriptions of MR imaging features.7-9 Here, we present 4 patients who underwent MR imaging and surgical resection of tumors in the posterior commissure and pineal region where the pathologic diagnosis was a PTPR. Case Reports Case 1A 27-year-old woman presented with headache and hydrocephalus. MR imaging at 1.5T revealed a mass centered between the posterior commissure and pineal region, which compressed the tectum and aqueduct (Fig 1). The mass was hyperintense on noncontrast T1-weighted images and enhanced heterogeneously after administration of gadolinium.The patient underwent ventriculostomy and surgical resection of the mass. Gross and histologic examinations of the mass did not display evidence of hemorrhage, calcification, melanin, keratin debris, or fat. Focal calcification was present in the adjacent pineal gland, which was displaced to the left. The pineal gland was normal on histologic examination. Case 2A 51-year-old woman presented with a headache and impairment of upward gaze. Imaging demonstrated a mass centered on the posterior commissure with mass effect on the pineal gland, aqueduct, and posterior third ventricle (Fig 2A). As in case 1, there was intrinsic hyperintensity on T1-weighted images throughout the mass on 1.5T unenhanced sequences. Small cystic areas were present in the mass, and the solid portions of the mass enhanced heterogeneously. Resection of the mass was accomplished by an infratentorial-supracerebellar approach, and immunohistochemical profiling confirmed the mass to be a PTPR. Case 3A 50-year-old woman presented with a 3-year history of gait imbalance, fatigue, and short-term memory loss. She reported a recent episode of confusion associated with weakness of the right lower extremity and was taken to the emergency department, where a 1.5T MR imaging examination demons...

Background and Purpose —We chose to evaluate the safety and efficacy of combined intrathrombus rtPA and intravenous heparin in cerebral venous thrombosis (CVT). Methods —We treated 12 patients with symptoms of 1 to 40 days’ duration (eg, headache, somnolence, focal deficits, seizures, and nausea and vomiting). Pretreatment MRI disclosed subtle hemorrhagic venous infarction in 4 patients, obvious hemorrhagic infarction in 2, small parenchymal hemorrhage from recent pallidotomy in 1, and no focal lesion in 5. Magnetic resonance venography and contrast venography identified thrombi in the superior sagittal sinus (SSS) in 3 patients; transverse/sigmoid sinus (TS/SS) in 2; SSS and both TS/SS in 1; SSS and 1 TS/SS in 5; and SSS, 1 TS/SS, and straight sinus in 1 patient. A loading dose of rtPA was instilled throughout the clot at 1 mg/cm, followed by continuous intrathrombus infusion at 1 to 2 mg/h. Intravenous heparin was infused concomitantly. Results —Flow was restored completely in 6 patients and partially in 3, with a mean rtPA dose of 46 mg (range, 23 to 128 mg) at a mean time of 29 hours (range, 13 to 77 hours). Symptoms improved in these 9 patients concomitantly with flow restoration. Flow could not be restored in 3 patients. In 1 of them, treatment was stopped when little progress had been made, and fibrinogen level dropped to 118 mg/dL. In the other 2 patients, hemorrhagic worsening occurred, and treatment was abbreviated after initial rtPA dosing. In 1 of these, the hematoma was evacuated. Conclusions —Our experience with intrathrombus rtPA in conjunction with intravenous heparin in patients with CVT is encouraging. This therapy should probably be regarded as unsafe in patients with obvious hemorrhage. Time to restore flow may be faster than with urokinase (an average of 71 hours has been reported for 29 documented patients). Further evaluation of rtPA with heparin in CVT is warranted.