Table of Contents
Review Articles
General Contents
- Diagnostic Accuracy of PET, SPECT, and Arterial Spin-Labeling in Differentiating Tumor Recurrence from Necrosis in Cerebral Metastasis after Stereotactic Radiosurgery
The authors retrospectively reviewed patients treated between 2007–2010 and identified 14 patients with cerebral metastasis who had clinical or radiographic progression following stereotactic radiosurgery and were imaged with arterial spin-labeling (ASL), FDG-PET, and thallium SPECT before stereotactic biopsy. FDG-PET and ASL were equally sensitive in detecting tumor progression (83%). The specificity of ASL was superior to that of the other modalities (100%, 75%, and 50%, respectively). A combination of modalities did not augment the sensitivity, specificity, positive predictive value, or negative predictive value of ASL.
- Optimal Diagnostic Indices for Idiopathic Normal Pressure Hydrocephalus Based on the 3D Quantitative Volumetric Analysis for the Cerebral Ventricle and Subarachnoid Space
Patients with suspected idiopathic normal pressure hydrocephalus (NPH) on the basis of the ventriculomegaly and a triad of symptoms underwent the CSF tap test. CSF volumes were extracted from a T2-weighted 3D spin-echo SPACE sequence on 3T MR imaging and were quantified semiautomatically. Twenty-four patients with tap-positive idiopathic NPH, 25 patients without response to the tap test, and 23 age-matched controls were included. The CSF volume of the parietal convexity had the highest area under the ROC curve in the discrimination of the tap-test response (0.768), followed by the z-Evans Index (0.758), and the upper-to-lower subarachnoid space ratio index (0.723). CSF volume of the parietal convexity of less than 38 mL, upper-to-lower subarachnoid space ratio of less than 0.33, and a z-Evans Index of greater than 0.42 are the newly proposed useful indices for idiopathic NPH diagnosis.
- Responses of the Human Brain to Mild Dehydration and Rehydration Explored In Vivo by 1H-MR Imaging and Spectroscopy
Serial T1WI and 1H-MR spectroscopy data were acquired in 15 healthy individuals at normohydration, at 12 hours of dehydration, and during 1 hour of oral rehydration. Osmotic challenges were monitored by serum measures, including osmolality and hematocrit. With dehydration, serum osmolality increased by 0.67% and brain tissue fluid decreased by 1.63%. MR imaging morphometry demonstrated corresponding decreases of cortical thickness and volumes of the whole brain, cortex, white matter, and hypothalamus/thalamus. These changes reversed during rehydration. The authors conclude that it is essential to control for hydration levels in studies on brain morphometry and metabolism in order to avoid confounding the findings.
- Brain Magnetic Susceptibility Changes in Patients with Natalizumab-Associated Progressive Multifocal Leukoencephalopathy
These authors retrospectively evaluated 12 patients with natalizumab–progressive multifocal leukoencephalopathy (PML), 5 with PML from other causes, and 55 patients with MS without progressive PML for comparison. They observed T2* or SWI signal abnormalities at the chronic stage in all patients with PML, but in patients without PML no areas of low SWI signal intensity were detected. PML—related to natalizumab or not—induces brain susceptibility changes within U-fibers or deep gray matter that are visible on T2* or SWI and potentially explained by iron deposition.
- Risk Factors for Hemorrhagic Complications following Pipeline Embolization Device Treatment of Intracranial Aneurysms: Results from the International Retrospective Study of the Pipeline Embolization Device
In this study of 793 patients with 906 aneurysms, 20 (2.5%) had intraparenchymal hemorrhage. Nine patients with intraparenchymal hemorrhage (45.0%) died, 10 (50.0%) had major neurologic morbidity, and 1 (5.0%) had minor neurologic morbidity. Variables associated with higher odds of intraparenchymal hemorrhage included treatment of ruptured aneurysms and the use of 3 or more Pipeline Embolization Devices. The Shuttle sheath was not associated with intraparenchymal hemorrhage.
- Bone-Subtracted Spinal CT Angiography Using Nonrigid Registration for Better Visualization of Arterial Feeders in Spinal Arteriovenous Fistulas
CTA images of the arterial and late arterial phases were used to obtain warped images of the late arterial phase by nonrigid registration that was adjusted to the arterial phase images. R-CTA images were then obtained by subtracting the warped images from the arterial phase images. R-CTA had a higher accuracy compared with conventional spinal CTA (80% versus 47%). The authors conclude that subtracted CTA imaging using nonrigid registration detects feeders of spinal arteriovenous fistulas more accurately and quickly than conventional CTA.
