In renal pelvis preparations isolated from the sheep, the location of the pacemaker and the pathway of conduction of the electrical impulse in the pelvis were analyzed in detail. An electrophysiological acquisition system was used allowing simultaneous recordings from 240 extracellular electrodes. Reconstruction of the spread of activity showed that the site of the pelvis pacemaker was, in virtually all cases, located at the pelvicalyceal border and never in the body of the pelvis or in the area of the pelviureteric junction. One single pacemaker was responsible for a particular spread of activation, and fusion of activity originating from two or more pacemakers did not place. Furthermore, spontaneous shifts of the pacemaker could occur from one site to another along the pelvicalyceal border. Conduction from the site of the current pacemaker to the pelviureteric junction and the ureter was slow, inhomogeneous, and contorted. Multiple instances of partial or total conduction block were seen at all levels in the pelvis and were not restricted to the pelviureteric junction. The occurrence of the conduction block did not seem to be related to the length of the preceding interval, implying that the refractory period did not play a major role in the genesis of intrapelvic conduction block. In conclusion, high-resolution mapping of the renal pelvis is possible and reveals location and behavior of the pacemaker and documents inhomogeneities in conduction and conduction block.

Vascular anomalies are present in the posterior circulation. In the case of this stroke patient, the posterior cerebral artery (PCA) was shown to have a fetal origin. A fetal PCA is classified as either a partial or complete fetal PCA, which can be determined by the presence of a remnant or absence of P1, the PCA segment directly arising from the terminal of the basilar artery. If absent, the PCA has arisen completely from the internal carotid artery (ICA) and is termed complete fetal PCA, or cfPCA. A partial fetal PCA, or pfPCA, is what is found when a hypoplastic segment persists. Here, we report a partial infarction of the oculomotor nucleus with ipsilateral fetal PCA in a 59-year-old female.

Each year there are an estimated 1.7 million adults in the United States that develop sepsis and nearly 16% of these adult patients die because of this disease process. Sepsis, however, can impact patients of all ages. Neonatal sepsis is currently one of the leading causes of morbidity and mortality among neonates. There are many complications of neonatal sepsis including meningitis, seizures, and hypoxic ischemic encephalopathy (HIE). HIE is estimated to impact one to five in 1000 live births worldwide, primarily impacting neonates. It is more commonly seen in premature infants and infants with low birth weights due to immature organ systems and a lack of adequate auto-regulatory mechanisms that would otherwise manage brain perfusion. In premature neonates, the most commonly recognized pathological pattern found on MRI is focal non-cystic white matter injury. HIE can also impact term infants as well. In these neonates, there exist two common MRI patterns that include either basal ganglia-thalamus ischemia, most often involving deep gray nuclei and perirolandic cortex, or watershed predominant ischemic changes that involve cortical gray matter. We report a 38-week-old male neonate born at gestation diagnosed with HIE secondary to neonatal sepsis with an MRI finding of isolated insular cortex hypersensitivity on fluid-attenuated inversion recovery (FLAIR) and T1-weighted imaging. Isolated insular cortex hypersensitivity can be seen in non-lacunar ischemic middle cerebral artery (MCA) territory strokes but it is not common for it to present as a sole finding. In our case, these findings persisted for several weeks without evidence of any common patterns of hypoxia-induced cerebrovascular insult on MRI imaging.

Encephaloceles are the type of dysraphism in which a skull defect allows for herniation of meninges, with or without the inclusion of neural tissue, and are commonly associated with agenesis of the corpus callosum. Encephaloceles are classified as frontal, occipital, or parietal, with parietal cephaloceles, or vertex cephaloceles (VC), being the least common. Despite this, VCs present as the most common cause of a midline scalp mass, displaying complex venous and neural malformations commonly referred to as the "tip of the iceberg." Atretic parietal encephaloceles (APC), a type of VC, are benign lesions arising from meningeal and vestigial tissue which have undergone fibrotic degeneration. As a result, prognosis will generally be better than other encephaloceles due to vestigial tissue involvement. Here, we report a neonate presenting with APC, corpus callosum agenesis, and a cingulate gyrus lesion, along with a sinus pericranii companion case for comparison.