Metric precision via soft-tissue landmarks in three-dimensional structured-light scans of human faces

OBJECTIVES

The goal of the current work was to investigate the suitability of ten facial soft-tissue landmarks (trichion, glabella, nasion, left and right orbital, subnasal, left and right porion, pogonion, gnathion) as reference points for metric facial analysis by analyzing their intra- and interserial precision in all three dimensions.

METHODS

The faces of 32 volunteers were scanned using a standardized protocol with a structured-light scanner (FaceSCAN(3D) Scientific Photolab 60 Hz; 3D Shape, Erlangen, Germany). Three examiners placed the landmarks twice within a 2-week interval. Image processing (Onyx Ceph(3); Image Instruments; Chemnitz, Germany) and statistical (SAS 9.2; SAS Institute, Cary, NC, USA) software was used for analysis. All measurements were corrected for mean values per patient and analyzed for intraserial and interserial error by model II ANOVA for a simple classification with random effects.

RESULTS

Median intraserial precision was 0.40 mm (range 0.05-1.01 mm) overall, including 0.40 mm (0.33-0.85 mm) on the x-axis, 0.64 mm (0.36-0.87 mm) on the y-axis, and 0.27 mm (0.05-1.01 mm) on the z-axis. Interserial precision was substantially lower at a median of 0.05 mm (0-0.22 mm), often not statistically assessable with intraserial precision. We observed no landmark-associated differences; in particular, the medians of the bilateral landmarks orbital (intraserial: 0.40 mm; interserial: 0.02 mm) and porion (intraserial: 0.36 mm; interserial: small and not assessable) were in the middle of the range of our results. Trichion (intraserial: 0.73 mm; interserial: 0.05 mm) and gnathion (intraserial: 0.87 mm; interserial: 0.20 mm) revealed the highest degrees of intraserial measurement imprecision. Outliers were identified in 1.2% (64 of 5400) of measurements.

CONCLUSION

All selected landmarks offer suitably high levels of intra- and interserial precision for the three-dimensional (3D) metric assessment of facial soft-tissue parameters. No difference between (bi)lateral and facial midline landmarks was noted.

[Cerebral venous thrombosis and subdural haematoma: complications of spontaneous intracranial hypotension]

We report on the case of a spontaneous intracranial hypotension with subdural hygroma, as well as cerebral venous thrombosis (CVT), both known complications of intracranial hypotension. The 45-year-old patient was subsequently treated - according to current guidelines for CVT - with anticoagulation, but developed subdural haematoma (SDH), which required neurosurgical treatment. Our case highlights the complex pathophysiological sequelae of intracranial hypotension, as well as the occasionally difficult treatment decisions. Subdural hygroma probably predisposes patients to SDH during anticoagulation. Thus, the potential benefit of anticoagulation needs to be weighed against the risk of SDH on an individual basis.

Three-year follow-up of a patient with early-onset Alzheimer's disease with presenilin-2 N141I mutation - case report and review of the literature

Autosomal dominant early-onset Alzheimer disease (EOAD) is a heterogeneous condition that has been associated with mutations in 3 different genes: the amyloid precursor protein (APP), presenilin 1 (PSEN1), and presenilin 2 (PSEN2) genes. Most cases are due to mutations in the PSEN1 gene, whereas mutations in the APP and PSEN2 genes are rare. Mutation analysis of the APP, PSEN1 and PSEN2 genes was performed. We herein report the case of a German EOAD patient with a family history of dementia and a missense mutation at codon 141 (N141I) of the PSEN2 gene. To our knowledge, this is the first German EOAD patient without a Volga-German ancestry and a positive family history for dementia carries the mutation PSEN-2 N141I. The patient came to our clinic for the first time when she was 47 years old. During the following 3 years, her Mini-Mental State Examination (MMSE) score dropped from 28 to 0. Mild cognitive impairment (MCI) was an early symptom that was already present during the first consultation. The concentration in cerebrospinal fluid (CSF) of tau-protein (1151 pg/ml) was increased, whereas the concentration of beta-amyloid protein (Abeta1-42) was decreased (335 pg/ml). Magnetic resonance imaging (MRI) revealed only slight changes in the early stage of the disease and positron emission tomography with (18F) fluoro-2-deoxy-D-glucose (18F-FDG PET) demonstrated glucose reduction left parietal and in the precuneus region. Follow-up MRI and 18F-FDG PET studies showed progression of atrophy of the left entorhinal cortex with relative sparing of the hippocampus and progressive hypometabolism of both temporoparietal lobes and left frontal lobe.