Carotid artery pulse wave time characteristics to quantify ventriculoarterial responses to orthostatic challenge.

Central blood pressure waveforms contain specific features related to cardiac and arterial function. We investigated posture-related changes in ventriculoarterial hemodynamics by means of carotid artery (CA) pulse wave analysis. ECG, brachial cuff pressure, and common CA diameter waveforms (by M-mode ultrasound) were obtained in 21 healthy volunteers (19-30 yr of age, 10 men and 11 women) in supine and sitting positions. Pulse wave analysis was based on a timing extraction algorithm that automatically detects acceleration maxima in the second derivative of the CA pulse waveform. The algorithm enabled determination of isovolumic contraction period (ICP) and ejection period (EP): ICP=43+/-8 (SD) ms (4-ms precision), and EP=302+/-16 (SD) ms (5-ms precision). Compared with the supine position, in the sitting position diastolic blood pressure (DBP) increased by 7+/-4 mmHg (P<0.001) and R-R interval decreased by 49+/-82 ms (P=0.013), reflecting normal baroreflex response, whereas EP decreased to 267+/-19 ms (P<0.001). Shortening of EP was significantly correlated to earlier arrival of the lower body peripheral reflection wave (r2=0.46, P<0.001). ICP increased by 7+/-7 ms (P<0.001), the ICP-to-EP ratio increased from 14+/-3% (supine) to 19+/-3% (P<0.001) and the DBP-to-ICP ratio decreased by 7% (P=0.023). These results suggest that orthostasis decreases left ventricular output as a result of arterial wave reflections and, presumably, reduced cardiac preload. We conclude that CA ultrasound and pulse wave analysis enable noninvasive quantification of ventriculoarterial responses to changes in posture.

The onset of ventricular isovolumic contraction as reflected in the carotid artery distension waveform.

The blood pressure waveform carries information about the cardiac contraction and the impedance characteristics of the vascular bed. Here, we demonstrate that the start of isovolumic ventricular contraction is persistently reflected as an inflection point in the pressure wave as recorded in the aortic root (TP(IC)) as well as in the carotid artery distension waveform (TD(IC)) as it travels down the arterial tree. In a group of six patients with normal pressure gradients across the aortic valve after valve replacement, the TP(IC) had a small delay with respect to the onset of isovolumic ventricular contraction (<10 ms). In a group (n = 21) of young presumably healthy volunteers, the inflection point occurred persistently in the carotid distension waveform, as recorded by means of ultrasound, before the systolic foot (intersubject delay between inflection point and systolic foot: mean +/- SD = 40.0 +/- 9.4 ms, intrasubject SD 4.6 ms). Retrograde coronary blood flow during isovolumic ventricular contraction may be the origin of the persistent end-diastolic pressure and distension perturbation. This study shows that the duration of the isovolumic contraction can be reliably extracted from the carotid artery distension waveform.

Abnormal Profiles of Local Functional Connectivity Proximal to Focal Cortical Dysplasias.

INTRODUCTION: Focal cortical dysplasia (FCD) is a congenital malformation of cortical development that often leads to medically refractory epilepsy. Focal resection can be an effective treatment, but is challenging as the surgically relevant abnormality may exceed the MR-visible lesion. The aim of the current study is to develop methodology to characterize the profile of functional connectivity around FCDs using resting-state functional MRI and in the individual patient. The detection of aberrant connectivity may provide a means to more completely delineate the clinically relevant lesion. MATERIALS AND METHODS: Fifteen FCD patients (age, mean±SD: 31±11 years; 11 males) and 16 matched healthy controls (35±9 years; 7 males) underwent structural and functional imaging at 3 Tesla. The cortical surface was reconstructed from the T1-weighted scan and the registered functional MRI data was spatially normalized to a common anatomical standard space employing the gyral pattern. Seed-based functional connectivity was determined in all subjects for all dysplasia locations. A single patient was excluded based on an aberrant FCD seed time series. Functional connectivity as a function of geodesic distance (along the cortical surface) was compared between the individual patients and the homotopic normative connectivity profiles derived from the controls. RESULTS: In 12/14 patients, aberrant profiles of functional connectivity were found, which demonstrated both hyper- and hypoconnectivity as well as combinations. Abnormal functional connectivity was typically found (also) beyond the lesion visible on structural MRI, while functional connectivity profiles not related to a lesion appeared normal in patients. CONCLUSION: This novel functional MRI technique has potential for delineating functionally aberrant from normal cortex beyond the structural lesion in FCD, which remains to be confirmed in future research.

Posttraumatic skull hemangioma: case report.

Intraosseous cavernous hemangiomas of the skull are rare lesions for which the origin is unclear. The authors present a case in which there was a radiologically documented history of trauma preceding the development of a hemangioma in the frontal bone. In a review of the literature the authors found 83 cases of skull hemangiomas, and 43% of the lesions were located in the frontal bone. In 25% of these lesions, previous trauma was reported anamnestically. The present case and radiological findings related to it suggest a causal relationship between trauma and the development of intraosseous hemangioma.