Infection with Zika virus (ZIKV) is associated with human congenital fetal anomalies. To model fetal outcomes in nonhuman primates, we administered Asian-lineage ZIKV subcutaneously to four pregnant rhesus macaques. While non-pregnant animals in a previous study contemporary with the current report clear viremia within 10–12 days, maternal viremia was prolonged in 3 of 4 pregnancies. Fetal head growth velocity in the last month of gestation determined by ultrasound assessment of head circumference was decreased in comparison with biparietal diameter and femur length within each fetus, both within normal range. ZIKV RNA was detected in tissues from all four fetuses at term cesarean section. In all pregnancies, neutrophilic infiltration was present at the maternal-fetal interface (decidua, placenta, fetal membranes), in various fetal tissues, and in fetal retina, choroid, and optic nerve (first trimester infection only). Consistent vertical transmission in this primate model may provide a platform to assess risk factors and test therapeutic interventions for interruption of fetal infection. The results may also suggest that maternal-fetal ZIKV transmission in human pregnancy may be more frequent than currently appreciated.

Phase contrast (PC) magnetic resonance imaging with a three-dimensional, radially undersampled acquisition allows for the acquisition of high resolution angiograms and velocimetry in dramatically reduced scan times. However, such an acquisition is sensitive to blurring and artifacts from offresonance and trajectory errors. A dual-echo trajectory is proposed with a novel trajectory calibration from prescan data coupled with a multi-frequency reconstruction to correct for these errors. Comparisons of phantom data and in vivo results from volunteer, and patients with arteriovenous malformations patients are presented with and without these corrections and show significant improvement of image quality when both corrections are applied. The results demonstrate significantly improved visualization of vessels, allowing for highly accelerated PC acquisitions without sacrifice in image quality. Volumetric phase contrast (PC) MR imaging with velocity encoding in three spatial dimensions holds the potential to be a comprehensive vascular imaging method; providing both anatomical and quantitative velocity measurements, all without the use of a contrast agent. As a lumenographic imaging tool, it has been effectively used for the identification of aneurysms, arteriovenous malformations (1), and vascular stenoses (2) in the cerebrovascular system, great vessels, and renal arteries. Additional hemodynamic information can be obtained through postprocessing of the acquired anatomical and velocity data, providing either velocity visualization and/or quantitative hemodynamic analysis. Visualization of complex velocity fields can be performed by flow vectors, streamlines, and particle traces to visually identify pathologic flow patterns (3). Quantitative flow measurements can be accomplished retrospectively with oblique reformats, avoiding difficulties of prospectively targeted two-dimensional (2D) PC measurements. Hemodynamic measures such as wall sheer stress and relative pressure can be determined directly from the velocity data (4,5). However, despite the plethora of diagnostic measures available from 3D PC, its clinical use has been hindered by relatively lengthy imaging times and the occurrence of flow related artifacts.For 3D PC to become a viable clinical solution, the scan time for images of diagnostic resolution must be reduced. This has been achieved through protocol optimization for vascular territories with larger vessels (6), which usually still results in extended imaging times. Parallel imaging techniques (7,8) can be used in conjunction with optimized protocols, but generally only allow accelerations on the order of 2-4 and can lead to additional signal-to-noise ratio (SNR) degradation. In addition to these accelerated imaging approaches, non-Cartesian trajectories may be used for more efficient sampling schemes, accelerated imaging by undersampling, and the reduction of flow related artifacts.We have previously introduced Vastly undersampled Isotropic PRojection (VIPR) imaging (9), a 3D radial trajectory with angul...

The role of the amygdala in major depression was investigated. Resting regional cerebral metabolic rate (rCMRglu) was measured with [18F]fluorodeoxyglucose positron emission tomography (PET) in two samples of subjects using two different PET cameras. The samples consisted of 10 and 17 medication-free depressives and 11 and 13 controls, respectively. Using coregistration of PET and magnetic resonance images, regions were individually delineated for the amygdala and thalamus, the latter of which was used as a control region. Within the depressed groups, right amygdalar rCMRglu was positively correlated with negative affect. Thalamic rCMRglu was not related to negative affect, and amygdalar rCMRglu accounted for a significant portion of variance in depressives' negative affect scores over and above the contribution of thalamic rCMRglu.

Background and Purpose— Arterial wall enhancement on vessel wall MRI was described in intracranial inflammatory arterial disease. We hypothesized that circumferential aneurysmal wall enhancement (CAWE) could be an indirect marker of aneurysmal wall inflammation and, therefore, would be more frequent in unstable (ruptured, symptomatic, or undergoing morphological modification) than in stable (incidental and nonevolving) intracranial aneurysms. Methods— We prospectively performed vessel wall MRI in patients with stable or unstable intracranial aneurysms. Two readers independently had to determine whether a CAWE was present. Results— We included 87 patients harboring 108 aneurysms. Interreader and intrareader agreement for CAWE was excellent (κ=0.85; 95% confidence interval, 0.75–0.95 and κ=0.90; 95% confidence interval, 0.83–0.98, respectively). A CAWE was significantly more frequently seen in unstable than in stable aneurysms (27/31, 87% versus 22/77, 28.5%, respectively; P <0.0001). Multivariate logistic regression, including CAWE, size, location, multiplicity of aneurysms, and daily aspirin intake, revealed that CAWE was the only independent factor associated with unstable status (odds ratio, 9.20; 95% confidence interval, 2.92–29.0; P =0.0002). Conclusions— CAWE was more frequently observed in unstable intracranial aneurysms and may be used as a surrogate of inflammatory activity in the aneurysmal wall.