Transsphenoidal surgery seems to be a reasonably safe procedure, with a mortality rate of less than 1%. However, a significant number of complications do occur. The incidence of these complications seems to be higher, with statistical significance, in the hands of less experienced surgeons. The learning curve seems to be relatively shallow, because a statistically significantly decreased incidence of morbidity and death could be documented after 200 and even 500 transsphenoidal operations. Better understanding of the indications for transsphenoidal surgery and improved familiarity with the regional anatomy should further lower the incidence of death and morbidity resulting from this procedure in the hands of all neurosurgeons.

Objective: To evaluate the frequency of HIV-associated neurocognitive disorder (HAND) in HIV1 individuals and determine whether the frequency of HAND changed over 4 years of follow-up. Methods:The Multicenter AIDS Cohort Study (MACS) is a prospective study of gay/bisexual men.Beginning in 2007, all MACS participants received a full neuropsychological test battery and functional assessments every 2 years to allow for HAND classification.

The purpose of this study was to determine the pattern and extent of caudate nucleus and putamen atrophy in HIV-infected men with well-controlled immune status and viral replication. 155 men underwent structural brain magnetic resonance imaging; 84 were HIV-infected and 71 were uninfected controls. MRI data were processed using the Fully Deformable Segmentation routine, producing volumes for the right and left caudate nucleus and putamen, and 3-D maps of spatial patterns of thickness. There was significant atrophy in the HIV-infected men in both the caudate and putamen, principally in the anterior regions. The volume of the basal ganglia was inversely associated with the time since first seropositivity, suggesting that either there is a chronic, subclinical process that continues in spite of therapy, or that the extent of the initial insult caused the extent of atrophy.Electronic supplementary materialThe online version of this article (doi:10.1007/s11682-011-9113-8) contains supplementary material, which is available to authorized users.

Background:The purpose of this study was to evaluate the relationship between cognitive perfor-

A novel approach for quantifying cerebral blood flow (CBF) is proposed that combines the bookend technique of calculating cerebral perfusion with an automatic postprocessing algorithm. The reproducibility of the quantitative CBF (qCBF) measurement in healthy controls (N ‫؍‬ 8) showed a higher intraclass correlation coefficient (ICC) and lower coefficient of variation (COV) when calculated with automatic analysis (ICC/COV ‫؍‬ 0.90/0.09) than when compared to conventional manual analysis (ICC/COV ‫؍‬ 0.58/0.19). Also, the reproducibility in patients (N ‫؍‬ 25) was successfully evaluated with the automatic analysis (ICC/COV ‫؍‬ 0.81/0.14). In 175 consecutive clinical scans, we found 3.0% and 7.4% of qCBF decrease per decade in white matter (WM) (21.5 ؎ 6.66 ml/100 g-min) and gray matter (GM) (49.6 ؎ 16.2 ml/100 g-min), respectively. Cerebral blood volume (CBV) showed a significant 3.7% decrease per decade in GM (3.00 ؎ 0.94 ml/100 g) but not in WM (1.69 ؎ 0.40 ml/100 g). Bolus tracking cerebral perfusion has been shown to reflect the underlying pathophysiology in a variety of diseases including cerebrovascular occlusive disease, stroke, central nervous system tumors, and potentially Alzheimer's disease (1-5). Parametric images of cerebral perfusion are calculated by analyzing the tracer kinetics of a known tracer, whether it is: radio-labeled water in positron emission tomography (PET), iodinated contrast agent in computed tomography (CT), spin-labeled water in arterial spin labeling, or a paramagnetic contrast agent in dynamic susceptibility contrast (DSC) MR imaging. While radiolabeled PET is the standard of reference for quantification of cerebral perfusion, the necessity of a cyclotron limits its availability. CT has the potential to quantify perfusion; however, iodinated contrast and large doses of radiation are required. This is particularly problematic for frequent follow-up or in certain populations, such as pediatric patients in which the radiation dose should be minimized MR-based parametric images of relative cerebral blood flow (CBF) and cerebral blood volume (CBV) images using DSC analysis are commonly used to assess changes in cerebral perfusion. The development of quantitative MRbased perfusion (i.e., in ml/100 g-min) has been identified by the American Heart Association as a priority for treatment of acute stroke (6). However, quantitative perfusion MR with DSC analysis has been elusive and challenging (7-10).One approach to quantification of perfusion using MRI has been to assume a population-averaged value for normal white matter (WM) and determine quantitative values relative to "normal-appearing white matter." This method assumes that the average CBF value in WM is not significantly dependent on age, gender, and physiologic conditions, and calculates the population-averaged correction factor by setting WM CBF values to 22 ml/100 g/min (11-13). However, Mukherjee et al. (14) have shown that the individual subject-to-subject correction factor is favored over the population-averaged correction fac...

Introduction The purpose of this study was to characterize brain volumetric differences in HIV seropositive and seronegative men and to determine effects of age, cardiovascular risk, and HIV infection on structural integrity. Methods Magnetic resonance imaging was used to acquire high-resolution neuroanatomic data in 160 men aged 50 years and over, including 84 HIV seropositive and 76 seronegative controls. Voxel-based morphometry was used to derive volumetric measurements at the level of the individual voxel. Data from a detailed neuropsychological test battery were recombined into four summary scores representing psychomotor speed, visual memory, verbal memory, and verbal fluency. Results Both age and HIV status had a significant effect on both gray matter (GM) and white matter (WM) volume. The age-related GM atrophy was primarily in the superior temporal and inferior frontal regions; the HIV-related GM loss included the posterior and inferior temporal lobes, the parietal lobes, and the cerebellum. Among all subjects, the performance on neuropsychological tests, as indexed by a summary variable, was related to the volume of both the GM and WM. Contrary to our predictions, the CVD variables were not linked to brain volume in statistically adjusted models. Conclusion In the post-HAART era, having HIV infection is still linked to atrophy in both GM and WM. Secondly, advancing age, even in this relatively young cohort, is also linked to changes in GM and WM volume. Thirdly, CNS structural integrity is associated with overall cognitive functions, regardless of the HIV infection status of the study volunteers.

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This cross-sectional brain volumetric study indicates structural alterations early in HIV infection. The findings challenge the prevailing assumption that the brain is spared in this period. Revisiting the question of the brain's vulnerability to processes unfolding in the initial virus-host interaction and the early natural history may yield new insights into neurologic injury in HIV infection and inform neuroprotection strategies.