1,721,055 research outputs found
FISIOPATOLOGIA ED EMODINAMICA DELL’INSUFFICIENZA VENOSA CRONICA CEREBROSPINALE
No full textAccording to the physic principles regulating the cerebrospinal venous drainage, a list of
haemdoynamic parameters has been created and aimed to the sonographic evaluation of such
venous district. All these values demonstrated to be physiology-related, easily reproducible and
detectable by means of a new trans and extra-cranial echo-color Doppler protocol (ECD-TCCS) of
evaluation. This assessment has been tested on 60 healthy volunteers.
Experimental Part I: The extracranial venous outflow routes in clinically defined multiple
sclerosis (CDMS) have not previously been investigated. Sixty-five patients affected by CDMS,
and 235 controls composed, respectively, of healthy subjects, healthy subjects older than CDMS
patients, patients affected by other neurological diseases and older controls not affected by
neurological diseases but scheduled for venography (HAV-C) blindly underwent to ECD-TCCS
aimed to detecting at least two of five parameters of anomalous venous outflow. According to the
ECD-TCCS screening, patients and HAV-C further underwent selective venography of the azygous
and jugular venous system with venous pressure measurement. CDMS and ECD-TCCS venous
outflow anomalies were dramatically associated (OR 43, 95% CI 29 to 65, p<0.0001).
Subsequently, venography demonstrated in CDMS, and not in controls, the presence of multiple
severe extracranial stenosis, affecting the principal cerebrospinal venous segments; this provides a
picture of chronic cerebrospinal venous insufficiency (CCSVI) with four different patterns of
distribution of stenosis and substitute circle. CDMS is strongly associated with CCSVI, a scenario
that has not previously been described, characterized by abnormal venous haemodynamics
determined by extracranial multiple venous strictures of unknown origin. The location of venous
obstructions plays a key role in determining the clinical course of the disease
Experimental Part II: It has been hypothesized the presence of the relationship between a Doppler
cerebral venous hemodynamic insufficiency severity score (VHISS) and cerebrospinal fluid (CSF)
flow dynamics. For this reason 16 patients presenting with CCSVI and relapsing-remitting MS
(CCSVI-MS) and in eight healthy controls (HCs) were evaluated using validated echo-Doppler and
advanced 3T-MRI CSF flow measures. Compared with the HCs, the CCSVI-MS patients showed a
significantly lower net CSF flow (p=0.027) which was highly associated with the VHISS (r=0.8280,
r2=0.6855; p=0.0001). This study demonstrates that venous outflow disturbances in the form of
CCSVI significantly impact on CSF pathophysiology in patients with MS
Doppler haemodynamics of cerebral venous return
No full textPhysiologic functioning of the cerebrovenous system is indispensable for maintaining normal brain function. However, in contrast to the cerebroarterial system, the cerebral venous return is not routinely investigated. Combined high-resolution echo-colour-Doppler (ECD) and transcranial colour coded Doppler sonography (TCCS) represents an ideal method to investigate the haemodynamics of cerebral venous return. TCCS-ECD is noninvasive, repeatable, cost-effective and permits to investigate the cerebral venous outflow in its dependence upon changes in posture and the alternating pressure gradients of the thoracic pump. Several authors reported normal parameters concerning related aspects of cerebral venous return. However, there is no ECD-TCCS standardization of what can be considered a normal venous return. The authors have summarized the current knowledge of the Doppler haemodynamics of the cerebrovenous system and propose a list of reproducible clinical parameters for its sonographic evaluation. In future, the development of this diagnostic technique could be of singular interest in iron-related inflammatory and neurodegenerative disorders like multiple sclerosis
Comment on "Reproducibility of cerebrospinal venous blood flow and vessel anatomy with the use of phase contrast-vastly undersampled isotropic projection reconstruction and contrast-enhanced MRA".
Full text linkFusion imaging technology of the intracranial veins
No full textOBJECTIVES: Fusion imaging technology (FIT) combines different imaging techniques by means of properly designed software. The aim of this study was to validate the ultrasonographic representation of intracranial vein anatomy by combining transcranial echo-colour Doppler (TECD) with conventional magnetic resonance imaging (MRI). In addition, we investigated the possibility of insonating the veins of the base of the skull through the novel condylar window. METHODS: We examined venous brain circulation in five healthy subjects by means of FIT, using a 1.5 T MR scanner and an ultrasound TECD equipped with Virtual Navigator technology.Results and conclusionsInsonation of the Rosenthal and other intracranial veins through the classical transtemporal window, based on anatomical assumption, but never before validated by means of FIT study, was confirmed. Moreover, in all five subjects, FIT demonstrated the possibility of insonating the petrosal sinuses and the cavernous sinus area through the novel transcondylar approach. In conclusion, the feasibility of FIT of the intracranial veins potentially permits to study subjects in different postures and/or at the bed of non-transportable patients, after the initial MRI acquisition. Finally, the novel transcondylar approach allows obtaining haemodynamic information from the cavernous and the petrosal sinuses usually not investigated by TECD alone
The controversy on chronic cerebrospinal venous insufficiency
No full textThe objective of this review is to analyze the actual scientific controversy on chronic cerebrospinal venous insufficiency (CCSVI) and its association with both neurodegenerative disorders and multiple sclerosis (MS). We revised all published studies on prevalence of CCSVI in MS patients, including ultrasound and catheter venography series. Furthermore, we take into consideration other publications dealing with the pathophysiologic consequences of CCSVI in the brain, as well as ecent data characterizing the pathology of the venous wall in course of CCSVI. Finally, safety and pilot data on effectiveness of endovascular CCSVI treatment were further updated. Studies of prevalence show a big variability in prevalence of CCSVI in MS patients assessed by established ultrasonographic criteria. This could be related to high operator dependency of ultrasound. However, 12 studies, by the means of more objective catheter venography, show a prevalence >90% of CCSVI in MS. Global hypo-hypoperfusion of the brain, and reduced cerebral spinal fluid dynamics in MS was shown to be related to CCSVI. Postmortem studies and histology corroborate the 2009 International Union of Phlebology (UIP) Consensus decision to insert CCSVI among venous malformations. Finally, safety of balloon angioplasty of the extracranial veins was certainly demonstrated, while prospective data on the potential effectiveness of endovascular treatment of CCSVI support to increase the level of evidence by proceeding with a randomized control trial (RCT). Taking into account the current epidemiological data, including studies on catheter venography, the autoptic findings, and the relationship between CCSVI and both hypo-perfusion and cerebro-spinal fluid flow, we conclude that CCSVI can be definitively inserted among the medical entities. Research is still inconclusive in elucidating the CCSVI role in the pathogenesis of neurological disorders. The controversy between the vascular and the neurological community is due to the great variability in prevalence of CCSVI in MS patients by the means of venous ultrasound assessment. More reproducible and objective CCSVI assessment is warranted. Finally, current RCT may elucidate the role of CCSVI endovascular treatment
Chronic cerebro-spinal venous insufficiency
No full textThe Oxford Textbook of Vascular Surgery draws on the expertise of over 130 specialist contributors to encompass the field of vascular surgery. Through the use of figures, findings of contemporary trials, and additional online content, this textbook is an excellent study material for surgical trainees entering their final two years of training, in addition to serving as an effective reference source for practicing surgeons
Impact of Jugular Vein Valve Function on Cerebral Venous Haemodynamics
No full textWe quantify the effect of internal-jugular vein function on intracranial venous haemodynamics, with particular attention paid to venous reflux and intracranial venous hypertension. Haemodynamics in the head and neck is quantified by computing the velocity, flow and pressure fields, and vessel cross-sectional area in all major arteries and veins. For the computations we use a global, closed-loop multi-scale mathematical model for the entire human circulation, recently developed by the first two authors. Validation of the model against in vitro and in vivo Magnetic Resonance Imaging (MRI) measurements have been reported elsewhere. Here, the circulation model is equipped with a sub-model for venous valves. For the study, in addition to a healthy control, we identify two venous-valve related conditions, namely valve incompetence and valve obstruction. A parametric study for subjects in the supine position is carried out for nine cases. It is found that valve function has a visible effect on intracranial venous haemodynamics, including dural sinuses and deep cerebral veins. In particular, valve obstruction causes venous reflux, redirection of flow and intracranial venous hypertension. The clinical implications of the findings are unknown, though they may relate to recent hypotheses linking some neurological conditions to extra-cranial venous anomalies
Attenuation of the increase of heart rate and oxygen consumption during progressive exercise in professional rugby players
No full textBackground: The response of oxygen uptake (VO2) and heart rate (HR) to continuous progressive large muscle mass exercise is not always linear. This study aimed to compare the patterns of the Speed/VO2 (S/VO2) and speed/HR (S/HR) relationships during an incremental treadmill-running test in professional rugby players. Methods: Fourteen professional rugby athletes performed a maximal incremental treadmill-running test, following the Conconi test protocol. Speed, heart rate, and gas exchange parameters were recorded. The slope of the S/VO2 and S/HR relationships were mathematically determined. Results: The S/VO2 and S/HR relationships were linear up to a submaximal speed and curvilinear thereafter. The speed of locomotion at which the slope of the S/VO2 and S/HR relationships start to attenuate (VO2att and HRatt) were coincident (12.3±1.0 and 12.4±0.9 km/h), strongly correlated and in good agreement. VO2 values at VO2att (44.9±8.7 mL/kg/min) were significantly correlated with VO2 values at the ventilatory threshold (43.3±6.0 mL/kg/min) (R2=0.83, P=0.001) and in good agreement. The running speed/VO2 ratio (ΔS/ΔVO2) up to VO2att was significantly lower than that beyond VO2att (2.98±1.1 vs 5.16±2.31); P<0,001). Conclusions: The speed/oxygen uptake and S/HR relationships during progressive exercise start to attenuate at a coincident exercise intensity, and at oxygen uptake values strongly correlated with the ventilatory threshold. These findings further support the usefulness of the attenuation of the S/HR relationship as a practical tool for exercise testing and training purposes in professional rugby players
The omohyoid muscle entrapment of the internal jugular vein. A still unclear pathogenetic mechanism
No full textOBJECTIVES:: To evaluate the role of the omohyoid muscle anatomic variants as a possible reversible cause of internal jugular vein extrinsic compression. METHOD:: We describe a chronic cerebro-spinal venous insufficiency patient, who presented a omohyoid muscle entrapment of the internal jugular vein, confirmed by both magnetic resonance venography and ultrasound investigation. A omohyoid muscle surgical transection together with a patch angioplasty was performed. RESULTS:: The surgical procedure led to both IJV flow restoration and neurological improvement. CONCLUSIONS:: The omohyoid muscle compression on the internal jugular vein seems to be a possible cause of venous obstruction, but several anatomical and patho-physiological aspects need further investigations. Such picture might cause balloon venous angioplasty inefficacy and needs to be preoperatively considered
Riduzione della carica batterica totale quantificata mediante analisi biomolecolare in ulcere infette trattate con Cutimed® Sorbact®.
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