Magnetic resonance imaging of the brainstem in children, part 2: acquired pathology of the pediatric brainstem.

Part 1 of this series of two articles describes conventional and advanced MRI techniques that are useful for evaluating brainstem pathologies. In addition, it provides a review of the embryology, normal progression of myelination, and clinically and radiologically salient imaging anatomy of the normal brainstem. Finally, it discusses congenital diseases of the brainstem with a focus on distinctive imaging features that allow for differentiating pathologies. Part 2 of this series of two articles includes discussion of neoplasms; infections; and vascular, demyelinating, toxic, metabolic and miscellaneous disease processes affecting the brainstem. The ultimate goal of this pair of articles is to empower the radiologist to add clinical value in the care of pediatric patients with brainstem pathologies.

Magnetic resonance imaging of the brainstem in children, part 1: imaging techniques, embryology, anatomy and review of congenital conditions.

Part 1 of this series of two articles describes conventional and advanced MRI techniques that are useful for evaluating brainstem pathologies. In addition, it provides a review of the embryology, normal progression of myelination, and clinically and radiologically salient imaging anatomy of the normal brainstem. Finally, it discusses congenital diseases of the brainstem with a focus on distinctive imaging features that allow for differentiating pathologies. Part 2 of this series of two articles includes discussion of neoplasms; infections; and vascular, demyelinating, toxic and metabolic, and miscellaneous disease processes affecting the brainstem. The ultimate goal of this pair of articles is to empower the radiologist to add clinical value in the care of pediatric patients with brainstem pathologies.

Natural history of grade I-II blunt traumatic aortic injury.

BACKGROUND: Endovascular aortic repair has revolutionized the management of traumatic blunt aortic injury (BAI). However, debate continues about the extent of injury requiring endovascular repair, particularly with regard to minimal aortic injury. Therefore, we conducted a retrospective observational analysis of our experience with these patients. METHODS: We retrospectively reviewed all BAI presenting to an academic level I trauma center over a 10-year period (2000-2010). Images were reviewed by a radiologist and graded according to Society for Vascular Surgery guidelines (grade I-IV). Demographics, injury severity, and outcomes were recorded. RESULTS: We identified 204 patients with BAI of the thoracic or abdominal aorta. Of these, 155 were deemed operative injuries at presentation, had grade III-IV injuries or aortic dissection, and were excluded from this analysis. The remaining 49 patients had 50 grade I-II injuries. We managed 46 grade I injuries (intimal tear or flap, 95%), and four grade II injuries (intramural hematoma, 5%) nonoperatively. Of these, 41 patients had follow-up imaging at a mean of 86 days postinjury and constitute our study cohort. Mean age was 41 years, and mean length of stay was 14 days. The majority (48 of 50, 96%) were thoracic aortic injuries and the remaining two (4%) were abdominal. On follow-up imaging, 23 of 43 (55%) had complete resolution of injury, 17 (40%) had no change in aortic injury, and two (5%) had progression of injury. Of the two patients with progression, one progressed from grade I to grade II and the other progressed from grade I to grade III (pseudoaneurysm). Mean time to progression was 16 days. Neither of the patients with injury progression required operative intervention or died during follow-up. CONCLUSIONS: Injury progression in grade I-II BAI is rare (~5%) and did not cause death in our study cohort. Given that progression to grade III injury is possible, follow-up with repeat aortic imaging is reasonable.

Traumatic abdominal aortic dissection in a 16-month-old child.

Abdominal aortic injury after blunt trauma is rare in the pediatric population. There have been fewer than 20 reported cases in the literature since 1960, and most were the result of motor vehicle collisions. We report the case of a 16-month-old boy who is the youngest reported patient to sustain this type of injury. We discuss the radiologic findings in multiple imaging modalities, mechanisms, associated injuries and management options.

The role of human metapneumovirus in upper respiratory tract infections in children: a 20-year experience.

BACKGROUND: The role that human metapneumovirus (hMPV) plays in the etiology of upper respiratory tract infections (URIs) in children over a period of many years has not been evaluated previously. METHODS: By use of real-time reverse-transcriptase polymerase chain reaction, we retrospectively tested nasal wash (NW) specimens for hMPV that had been obtained from a cohort of 1532 infants and children with URIs who were prospectively followed for an average of 2.4 years during the period from 1982 to 2001. Virus genes were sequenced, and prospectively collected clinical data were analyzed. RESULTS: There were 2710 visits for URIs for which routine cultures did not reveal a viral etiology. Archival NW specimens from 2384 of these visits were available. hMPV RNA was detected in 118 (5%) of 2384 specimens. The mean age of the children with hMPV infection was 20 months, and 78% of illnesses occurred from December through May. Acute otitis media (AOM) was detected in 50% of these children. hMPV circulated each year, but the numbers of isolates detected varied by year. Reinfections with both homologous and heterologous strains occurred. Four distinct genetic lineages were present over the 20 years of surveillance, with several different lineages circulating during some seasons. CONCLUSIONS: hMPV was detected in a substantial number of children with URIs and concomitant AOM.

The transmembrane domain of the respiratory syncytial virus F protein is an orientation-independent apical plasma membrane sorting sequence.

The processes that facilitate transport of integral membrane proteins though the secretory pathway and subsequently target them to particular cellular membranes are relevant to almost every field of biology. These transport processes involve integration of proteins into the membrane of the endoplasmic reticulum (ER), passage from the ER to the Golgi, and post-Golgi trafficking. The respiratory syncytial virus (RSV) fusion (F) protein is a type I integral membrane protein that is uniformly distributed on the surface of infected nonpolarized cells and localizes to the apical plasma membrane of polarized epithelial cells. We expressed wild-type or altered RSV F proteins to gain a better understanding of secretory transport and plasma membrane targeting of type I membrane proteins in polarized and nonpolarized epithelial cells. Our findings reveal a novel, orientation-independent apical plasma membrane targeting function for the transmembrane domain of the RSV F protein in polarized epithelial cells. This work provides a basis for a more complete understanding of the role of the transmembrane domain and cytoplasmic tail of viral type I integral membrane proteins in secretory transport and plasma membrane targeting in polarized and nonpolarized cells.