Younger facial looks are associate with a lower likelihood of several age-related morbidities in the middle-aged to elderly

BACKGROUND

Looking older for one's chronological age is associated with a higher mortality rate. Yet it remains unclear how perceived facial age relates to morbidity and the degree to which facial ageing reflects systemic ageing of the human body.

OBJECTIVES

To investigate the association between ΔPA and age-related morbidities of different organ systems, where ΔPA represents the difference between perceived age (PA) and chronological age.

METHODS

We performed a cross-sectional analysis on data from the Rotterdam Study, a population-based cohort study in the Netherlands. High-resolution facial photographs of 2679 men and women aged 51.5-87.8 years of European descent were used to assess PA. PA was estimated and scored in 5-year categories using these photographs by a panel of men and women who were blinded for chronological age and medical history. A linear mixed model was used to generate the mean PAs. The difference between the mean PA and chronological age was calculated (ΔPA), where a higher (positive) ΔPA means that the person looks younger for their age and a lower (negative) ΔPA that the person looks older. ΔPA was tested as a continuous variable for association with ageing-related morbidities including cardiovascular, pulmonary, ophthalmological, neurocognitive, renal, skeletal and auditory morbidities in separate regression analyses, adjusted for age and sex (model 1) and additionally for body mass index, smoking and sun exposure (model 2).

RESULTS

We observed 5-year higher ΔPA (i.e. looking younger by 5 years for one's age) to be associated with less osteoporosis [odds ratio (OR) 0.76, 95% confidence interval (CI) 0.62-0.93], less chronic obstructive pulmonary disease (OR 0.85, 95% CI 0.77-0.95), less age-related hearing loss (model 2; B = -0.76, 95% CI -1.35 to -0.17) and fewer cataracts (OR 0.84, 95% CI 0.73-0.97), but with better global cognitive functioning (g-factor; model 2; B = 0.07, 95% CI 0.04-0.10).

CONCLUSIONS

PA is associated with multiple morbidities and better cognitive function, suggesting that systemic ageing and cognitive ageing are, to an extent, externally visible in the human face.

Differences Between MR Brain Region Segmentation Methods: Impact on Single-Subject Analysis

For the segmentation of magnetic resonance brain images into anatomical regions, numerous fully automated methods have been proposed and compared to reference segmentations obtained manually. However, systematic differences might exist between the resulting segmentations, depending on the segmentation method and underlying brain atlas. This potentially results in sensitivity differences to disease and can further complicate the comparison of individual patients to normative data. In this study, we aim to answer two research questions: 1) to what extent are methods interchangeable, as long as the same method is being used for computing normative volume distributions and patient-specific volumes? and 2) can different methods be used for computing normative volume distributions and assessing patient-specific volumes? To answer these questions, we compared volumes of six brain regions calculated by five state-of-the-art segmentation methods: Erasmus MC (EMC), FreeSurfer (FS), geodesic information flows (GIF), multi-atlas label propagation with expectation–maximization (MALP-EM), and model-based brain segmentation (MBS). We applied the methods on 988 non-demented (ND) subjects and computed the correlation (PCC-v) and absolute agreement (ICC-v) on the volumes. For most regions, the PCC-v was good (>0.75), indicating that volume differences between methods in ND subjects are mainly due to systematic differences. The ICC-v was generally lower, especially for the smaller regions, indicating that it is essential that the same method is used to generate normative and patient data. To evaluate the impact on single-subject analysis, we also applied the methods to 42 patients with Alzheimer’s disease (AD). In the case where the normative distributions and the patient-specific volumes were calculated by the same method, the patient’s distance to the normative distribution was assessed with the z-score. We determined the diagnostic value of this z-score, which showed to be consistent across methods. The absolute agreement on the AD patients’ z-scores was high for regions of thalamus and putamen. This is encouraging as it indicates that the studied methods are interchangeable for these regions. For regions such as the hippocampus, amygdala, caudate nucleus and accumbens, and globus pallidus, not all method combinations showed a high ICC-z. Whether two methods are indeed interchangeable should be confirmed for the specific application and dataset of interest.

Quantification of Macrocirculation and Microcirculation in Brain Using Ultrasound Perfusion Imaging

OBJECTIVE

The aim of this study was to investigate the feasibility of simultaneous visualization of the cerebral macrocirculation and microcirculation, using ultrasound perfusion imaging (UPI). In addition, we studied the sensitivity of this technique for detecting changes in cerebral blood flow (CBF).

MATERIALS AND METHODS

We performed an observational study in ten healthy volunteers. Ultrasound contrast was used for UPI measurements during normoventilation and hyperventilation. For the data analysis of the UPI measurements, an in-house algorithm was used to visualize the DICOM files, calculate parameter images and select regions of interest (ROIs). Next, time intensity curves (TIC) were extracted and perfusion parameters calculated.

RESULTS

Both volume- and velocity-related perfusion parameters were significantly different between the macrocirculation and the parenchymal areas. Hyperventilation-induced decreases in CBF were detectable by UPI in both the macrocirculation and microcirculation, most consistently by the volume-related parameters. The method was safe, with no adverse effects in our population.

CONCLUSIONS

Bedside quantification of CBF seems feasible and the technique has a favourable safety profile. Adjustment of current method is required to improve its diagnostic accuracy. Validation studies using a 'gold standard' are needed to determine the added value of UPI in neurocritical care monitoring.

Low spontaneous variability in cerebral blood flow velocity in non-survivors after cardiac arrest

OBJECTIVE

To investigate spontaneous variability in the time and frequency domain in mean flow velocity (MFV) and mean arterial pressure (MAP) in comatose patients after cardiac arrest, and determine possible differences between survivors and non-survivors.

METHODS

A prospective observational study was performed at the ICU of a tertiary care university hospital in the Netherlands. We studied 11 comatose patients and 10 controls. MFV in the middle cerebral artery was measured with simultaneously recording of MAP. Coefficient of variation (CV) was used as a standardized measure of dispersion in the time domain. In the frequency domain, the average spectral power of MAP and MFV were calculated in the very low, low and high frequency bands.

RESULTS

In survivors CV of MFV increased from 4.66 [3.92-6.28] to 7.52 [5.52-15.23] % at T=72h. In non-survivors CV of MFV decreased from 9.02 [1.70-9.36] to 1.97 [1.97-1.97] %. CV of MAP was low immediately after admission (1.46 [1.09-2.25] %) and remained low at 72h (3.05 [1.87-3.63] %) (p=0.13). There were no differences in CV of MAP between survivors and non-survivors (p=0.30). We noticed significant differences between survivors and non-survivors in the VLF band for average spectral power of MAP (p=0.03) and MFV (p=0.003), whereby the power of both MAP and MFV increased in survivors during admission, while remaining low in non-survivors.

CONCLUSIONS

Cerebral blood flow is altered after cardiac arrest, with decreased spontaneous fluctuations in non-survivors. Most likely, these changes are the consequence of impaired intrinsic myogenic vascular function and autonomic dysregulation.

Computation of blood flow through collateral circulation of the superficial femoral artery

OBJECTIVE

Obliteration of collaterals during (endo)vascular treatment of peripheral arterial occlusive disease is considered detrimental. We use a model to calculate maximum collateral bed flow of the superficial femoral artery in order to provide insight in their hemodynamic relevance.

METHOD

A computational model was developed using digital subtraction angiographies in combination with Poiseuille's equation and Ohm's law. Lesions were divided into short and long (<15 cm and ≥15 cm, respectively) and into stenosis and occlusions. Data are presented in relation to the calculated maximum healthy superficial femoral artery flow.

RESULTS

Stenotic lesions are longer than occlusive lesions (P < 0.05) and occlusions had more and larger collaterals (P < 0.05). In all four study groups the collateral flow significantly increased the total flow (P < 0.05). The maximum collateral system flow in the stenosis and occlusion groups was 5.1% and 20.8% of healthy superficial femoral artery flow, respectively (P < 0.05), and there were no significant differences between short and long lesions (11.2% and 6.7% of healthy superficial femoral artery flow, respectively).

CONCLUSION

The maximum collateral system flow of the superficial femoral artery is only a fraction, with a maximum of one fifth, of healthy superficial femoral artery flow. Effects of collateral vessel occlusion during (endo)vascular treatment may therefore be without detrimental consequences.