Sagittal MRI often overestimates the degree of cerebellar tonsillar ectopia: a potential for misdiagnosis of the Chiari I malformation

Background

We hypothesized that by using coronal MRI, Chiari I malformation could be more precisely diagnosed, would provide simple anatomic landmarks, would provide information regarding asymmetry of hindbrain herniation, and would be a better method for analyzing the tonsillar herniation postoperatively when the opisthion has been removed.

Methods

Fifty consecutive pediatric patients diagnosed with Chiari I malformation had comparison between the measurements of their caudally descended cerebellar tonsils on midsagittal and coronal MRI images.

Results

On MRI coronal imaging, tonsillar asymmetry was found in 48 patients. Maximal left tonsillar descent was 20.9 mm, and maximal right tonsillar descent was 17.4 mm. On MRI sagittal imaging, tonsillar descent ranged from 5 to 27.4 mm. Fifty-eight % of patients had syringomyelia. Five patients (10 %) on coronal MRI were found to have both cerebellar tonsils that were less than 3 mm below the foramen magnum. However, all of these patients had greater than 3 mm of tonsillar ectopia on sagittal imaging. Nineteen patients (38 %) on coronal MRI were found to have one of the cerebellar tonsils that were less than 3 mm below the foramen magnum. Similarly, each of these had greater than 3 mm of tonsillar ecotpia as measured on midsagittal MRI. Also, based on these findings, Chiari I malformation is almost always an asymmetrical tonsillar ectopia.

Conclusions

Sagittal MRI overestimates the degree of tonsillar ectopia in patients with Chiari I malformation. Misdiagnosis may occur if sagittal imaging alone is used. The cerebellar tonsils are paramedian structures, and this should be kept in mind when interpreting midline sagittal MRI.

     

Experimental characterisation of porcine subcutaneous adipose tissue under blunt impact up to irreversible deformation

International Journal of Legal Medicine - A deeper understanding of the mechanical characteristics of adipose tissue under large deformation is important for the analysis of blunt force trauma, as...     

Podoplanin increases migration and angiogenesis in malignant glioma

Expression of podoplanin in glial brain tumors is grade dependent. While serving as a marker for tumor progression and modulating invasion in various neoplasms, little is known about podoplanin function in gliomas. Therefore we stably transfected two human glioma cell lines (U373MG and U87MG) with expression plasmids encoding podoplanin. The efficacy of transfection was confirmed by FACS analysis, PCR and immunocytochemistry. Cells were then sorted for highly podoplanin expressing cells (U373P^high/U87P^high). Transfection did not influence the production of pro-angiogenic factors including VEGF, VEGF-C and D. Also, expression of VEGF receptors (VEGFR) remained unchanged except for U87P^high, where a VEGFR3 expression was induced. U373P^high showed significantly reduced proliferation as compared to mock transfected group. By contrast, podoplanin significantly increased migration and invasion into collagen matrix. Furthermore, conditioned media from P^high glioma cells strongly induced tube formation on matrigel. In conclusion, podoplanin increased migration of tumor cells and enhanced tube formation activity in endothelial cells independent from VEGF. Thus, podoplanin expression may be an important step in tumor progression.     

Mutations in COA6 cause Cytochrome c Oxidase Deficiency and Neonatal Hypertrophic Cardiomyopathy

COA6/C1ORF31 is involved in cytochrome c oxidase (complex IV) biogenesis. We present a new pathogenic COA6 variant detected in a patient with neonatal hypertrophic cardiomyopathy and isolated complex IV deficiency. For the first time, clinical details about a COA6‐deficient patient are given and patient fibroblasts are functionally characterized: COA6 protein is undetectable and steady‐state levels of complex IV and several of its subunits are reduced. The monomeric COX1 assembly intermediate accumulates. Using pulse‐chase experiments, we demonstrate an increased turnover of mitochondrial encoded complex IV subunits. Although monomeric complex IV is decreased in patient fibroblasts, the CI/CIII₂/CIV_n‐supercomplexes remain unaffected. Copper supplementation shows a partial rescue of complex IV deficiency in patient fibroblasts. We conclude that COA6 is required for complex IV subunit stability. Furthermore, the proposed role in the copper delivery pathway to complex IV subunits is substantiated and a therapeutic lead for COA6‐deficient patients is provided.     

Age-Related Outcomes After Transcatheter Aortic Valve Replacement: Insights From the SwissTAVI Registry

ObjectivesThe aim of this study was to investigate age-related outcomes of patients undergoing transcatheter aortic valve replacement (TAVR) as assessed in a nationwide, prospective, multicenter cohort study.BackgroundTAVR is the preferred treatment for elderly patients with severe aortic stenosis and is expanding into lower age groups.MethodsData from the SwissTAVI Registry were analyzed. Clinical outcomes were compared between patients 70 years of age or younger (n = 324), 70 to 79 years of age (n = 1,913), 80 to 89 years of age (n = 4,353), and older than 90 years of age (n = 507). Observed deaths were correlated with expected deaths in the general Swiss population using standardized mortality ratios.ResultsBetween February 2011 and June 2018, 7,097 patients (mean age 82.0 ± 6.4 years, 49.6% women) underwent TAVR at 15 hospitals in Switzerland. Procedural characteristics were similar; however, older patients more often had discharge to the referring hospital or a rehabilitation facility after TAVR. Using adjusted analyses, a linear trend for mortality (30-day adjusted hazard ratio [HR_adj]: 1.45; 95% confidence interval [CI]: 1.18 to 1.77; 1-year HR_adj: 1.12; 95% CI: 1.01 to 1.24), cerebrovascular accidents (30-day HR_adj: 1.35; 95% CI: 1.09 to 1.66; 1-year HR_adj: 1.21; 95% CI: 1.02 to 1.45), and pacemaker implantation (30-day HR_adj: 1.23; 95% CI: 1.12 to 1.34; 1-year HR_adj: 1.19; 95% CI: 1.09 to 1.30) was observed with increasing age. Furthermore, standardized mortality ratios were 12.63 (95% CI: 9.06 to 17.58), 4.09 (95% CI: 3.56 to 4.74), 1.63 (95% CI: 1.50 to 1.78), and 0.93 (95% CI: 0.76 to 1.14) for TAVR patients in relation to the Swiss population <70, 70 to 79, 80 to 89 and ≥90 years of age, respectively.ConclusionsIncreasing age is associated with a linear trend for mortality, stroke, and pacemaker implantation during early and longer-term follow-up after TAVR. Standardized mortality ratios were higher for TAVR patients younger than 90 years of age compared with expected rates of mortality in an age- and sex-matched Swiss population. (SWISS TAVI Registry; NCT01368250)