The inferior vena cava (IVC) is an essential but often overlooked structure at abdominal imaging. It is associated with a wide variety of congenital and pathologic processes and can be a source of vital information for referring clinicians. Initial evaluation of the IVC is most likely to occur at computed tomography performed for another indication. Many routine abdominal imaging protocols may result in suboptimal evaluation of the IVC; however, techniques to assist in specific evaluation of the IVC can be used. In this article, the authors review the spectrum of IVC variants and pathologic processes and the relevant findings from magnetic resonance imaging, angiography, sonography, and positron emission tomography. Embryologic development of the IVC and examples of congenital IVC variants, such as absence, duplication, left-sided location, azygous or hemiazygous continuation, and web formation, are described. The authors detail IVC involvement in Wilms tumor, leiomyosarcoma, adrenal cortical carcinoma, testicular carcinoma, hepatocellular carcinoma, renal cell carcinoma, and other neoplasms, as well as postsurgical, traumatic, and infectious entities (including filter malposition, mesocaval shunt, and septic thrombophlebitis). The implications of these entities for patient treatment and instances in which specific details should be included in the dictated radiology report are highlighted. Furthermore, the common pitfalls of IVC imaging are discussed. The information provided in this review will allow radiologists to detect and accurately characterize IVC abnormalities to guide clinical decision making and improve patient care.

Purpose To evaluate the reproducibility of regional apparent diffusion coefficient (ADC) measurements of the normal fetal brain in the second and third trimesters. Materials & Methods Fifty normal singleton fetuses between 19–37 weeks of gestation were studied without sedation from healthy pregnant women. Single-shot diffusion DWI of the fetal brain was obtained using a 1.5-Tesla MR scanner and a 6-channel body array coil. ADC maps were created using 0 and 1000 b-values along 3 orthogonal directions. Two examiners independently measured ADC values in the cerebellar hemispheres (CH), pons, thalamus, basal ganglia (BG), centrum semiovale (CSO), frontal (FWM), parietal (PWM), temporal (TWM), and occipital white matter (OWM). Correlation between ADC values and menstrual age was assessed by linear regression. The bias and agreement of ADC measurements were determined using Bland-Altman plots. Results ADC values either remained constant (BG, FWM, PWM, TWM, CSO) or decreased (CH, pons, thalamus) with advancing menstrual age. Mean intra-observer bias for ADC measurements was not significantly different from zero. Small differences in inter-observer bias were detected for CH (1.26 ± 0.20 vs. 1.20 ± 0.18, p = 0.006), PWM (1.37 ± 0.29 vs. 1.33 ± 0.26, p = 0.02), and CSO (1.36 ± 0.29 vs. 1.33 ± 0.28, p < 0.0001). Measurement agreement was acceptable. Conclusions ADC measurements in normal un-sedated fetuses in the second and third trimesters are reproducible except for small differences for PWM, CH, and CSO between examiners.

If these trends can be validated in greater numbers of patients, DTI may serve as an objective quantitative biomarker for disease progression in patients with upper motor neuron disease.

Erlichman JS, Boyer AC, Reagan P, Putnam RW, Ritucci NA, Leiter JC. Chemosensory responses to CO 2 in multiple brain stem nuclei determined using a voltage-sensitive dye in brain slices from rats. J Neurophysiol 102: 1577-1590, 2009. First published June 24, 2009 doi:10.1152/jn.00381.2009. We used epifluorescence microscopy and a voltage-sensitive dye, di-8-ANEPPS, to study changes in membrane potential during hypercapnia with or without synaptic blockade in chemosensory brain stem nuclei: the locus coeruleus (LC), the nucleus of the solitary tract, lateral paragigantocellularis nucleus, raphé pallidus, and raphé obscurus and, in putative nonchemosensitive nuclei, the gigantocellularis reticular nucleus and the spinotrigeminal nucleus. We studied the response to hypercapnia in LC cells to evaluate the performance characteristics of the voltagesensitive dye. Hypercapnia depolarized many LC cells and the voltage responses to hypercapnia were diminished, but not eradicated, by synaptic blockade (there were intrinsically CO 2 -sensitive cells in the LC). The voltage response to hypercapnia was substantially diminished after inhibiting fast Na ϩ channels with tetrodotoxin. Thus action potential-related activity was responsible for most of the optical signal that we detected. We systematically examined CO 2 sensitivity among cells in brain stem nuclei to test the hypothesis that CO 2 sensitivity is a ubiquitous phenomenon, not restricted to nominally CO 2 chemosensory nuclei. We found intrinsically CO 2 sensitive neurons in all the nuclei that we examined; even the nonchemosensory nuclei had small numbers of intrinsically CO 2 sensitive neurons. However, synaptic blockade significantly altered the distribution of CO 2 -sensitive cells in all of the nuclei so that the cellular response to CO 2 in more intact preparations may be difficult to predict based on studies of intrinsic neuronal activity. Thus CO 2 -sensitive neurons are widely distributed in chemosensory and nonchemosensory nuclei and CO 2 sensitivity is dependent on inhibitory and excitatory synaptic activity even within brain slices. Neuronal CO 2 sensitivity important for the behavioral response to CO 2 in intact animals will thus be determined as much by synaptic mechanisms and patterns of connectivity throughout the brain as by intrinsic CO 2 sensitivity.

Nasal gliomas (nasal glial heterotopia) are rare benign congenital frontonasal lesions occurring in approximately 1:20.000-40,000 live births. The diagnosis is rarely reported prenatally. Nasal gliomas are typically isolated lesions, with syndromic association being exceedingly rare. Metopic craniosynostosis can occur as an isolated abnormality or in association with multiple syndromes. This case is the first reported case of nasal glioma in association with craniosynostosis in the published literature.