Perspectives in Medicine最新文献

Background

Atherosclerotic stenoses of the intracranial arteries (ICAS) is associated with high risk of stroke after TIA. The prevalence of intracranial stenoses is considered to be low in Caucasians, however population-based data are lacking and only a minority of patients with acute TIA or stroke is evaluated for ICAS.

Methods

We prospectively examined the prevalence of stenoses of the pre- and intracerebral vessels using transcranial colour coded sonography (TCCS) in a population based cohort of all TIA patients in the community of Aarhus, Denmark in the period 1.3.2007–29.2.2008.

Results

The TIA cohort included 203 patients fulfilling the diagnostic criteria for TIA. We examined 195 patients with extra- and intracranial TCCD.

Any stenoses and symptomatic ICAS was found in 12.3% and 8.2%, respectively. The stenoses were located in the intracranial internal carotid artery in 3.6% and 3.1%, anterior cerebral artery in 0.5% and 0%, middle cerebral artery in 4.6% and 2.6%, intracranial vertebral artery in 2.1% and 1.5%, and in the basilar artery in 1.5% and 1.5%, respectively. In comparison, we found any stenoses and symptomatic stenoses in the extracranial carotid artery in 14.4% and 10.8%, and the extracranial vertebral artery in 5.6% and 2.1% of the patients, respectively. Carotid occlusion was found in 3.6%, combined extra- and intracranial stenoses in 4.9%.

Conclusion

The prevalence of ICAS was in this population-based TIA cohort of Caucasians comparable with the prevalence of carotid stenoses. Systematic evaluation for intracranial stenoses should be considered in all patients with acute ischemic cerebrovascular disease.

Background

Carotid angioplasty and stenting (CAS) is increasingly being used as a treatment alternative to endarterectomy (CEA), especially in patients aged <70 years with significant carotid artery stenosis. However, an in-stent restenosis (ISR) might endangering the long-term efficacy of CAS. The aim of this article was to review the current literature regarding incidence and clinical significance as well as predictors of in-stent restenosis.

Methods

We conducted a systematic review of the literature to identify all studies on the abovementioned factors.

Results

3 randomized-controlled trials comparing CAS and CEA and 13 single centre studies fulfilled our inclusion criteria. The occurrence of ISR after CAS ranged from 2.7 to 33% and was detected within the first year in most of the studies. The clinical impact as well as the therapeutic consequence of ISR remains unclear, but many baseline characteristics (age, prior CEA or radiation), procedural (insufficient stent deployment, stent dimensions, inflammatory marker) and follow-up factors (reduced HDL, diabetes mellitus) could be found to identify patients at special risk for ISR. A wide heterogeneity related to the definition and their corresponding ultrasound criteria for ISR was observed.

Conclusions

A close follow-up is suggested especially in those patients with predictors of an ISR. The wide range of ISR ultrasound definitions urges the need for an implementation of generally valid criteria in ISR diagnosis. Against the background of the unknown clinical significance of ISR and a lacking established treatment modality these findings should be taken into account when offering CAS as a treatment alternative to CEA.

Introduction

Neuroradiological techniques are known for their high spatial resolution in imaging of intracranial structures, in comparison with neurosonological techniques (TCCS), known for their high temporal resolution. An ideal study of intracranial circulation should combine the high temporal resolution of ultrasound with the high spatial resolution of Magnetic Resonance (MR) Imaging. This imaging fusion system is actually used for the ultrasound liver examination and it is known as Virtual Navigator. Therefore we implemented this system for the examination of the intracranial venous hemodynamics.

Patients and methods

Fifteen consecutive subjects (7 men and 8 women, mean age 51.5 ± 8.64 years) were chosen among patients who underwent standard TCCS examinations at our lab and had age >18 years, a suitable temporal acoustic window and a recently performed intracranial MR venography. The axial scanning approach was used from the temporal window and the standard TCCS examination was compared with the Virtual Navigator examination, for the insonation rate of the basal vein of Rosenthal (BVR), Galen vein (GV), Straight sinus (SRS) and Transverse sinus (TS).

Results and discussion

The insonation rates of the venous structures are only slightly improved for BVR (from 90% to 96.67%) but are substantially increased for SRS and TS (for this last one from 63.33% to 86.67%) with a statistically significant difference (p < 0.05).

Conclusions

The Virtual Navigator protocol can help to insonate the intracranial venous system.

In the Helsingborg Declaration the continuum of care consisting of pre-, intra- and posthospital organization of stroke services combined with evaluation of outcome measures and dedicated quality assessments was considered as key for best outcome. Despite the evidence of such measures there are still striking disparities in organized stroke care all over Europe. Aim of this paper is to describe current concepts used for process optimization in stroke care and to evaluate if methodologies used in industry provide additional benefit in order to address this issue.

We describe the transfer of a commonly accepted industrial maturity model to stroke care addressing structural, process and outcome quality. Moreover, this tool can be used to compare different stroke services and provides valuable information for their optimization by transferring best practices from “best in class” services as well as for prioritization of improvement measures.

Objective

(1) To provide an overview on 13 years experience on patients with musculoskeletal disorders in Pakistan. (2) To assess accuracy of ultrasound in musculoskeletal disorders. (3) To determine percentage of different regional pathologies referred for musculoskeletal ultrasound.

Material and methods

We scanned 25,437 patients coming from all over Pakistan including 18,715 males and 6722 females from 1 month to 85 years of age.

We used two ultrasound equipments with a multi-frequency (6–14 MHz) linear probe to perform studies in patients with possible musculoskeletal system problems.

Results

All patients with different joint or specific problems of musculoskeletal system were scanned, the total number of patients of any specific disorder was calculated and the accuracy of ultrasound was compared with MRI in a given percentage of patients.

Discussion

In all musculoskeletal disorders ultrasound was found to be accurate in about 84.8%. It was 83.5% accurate in the cases which went for MRI, its accuracy with other lab tests was 81.2% and that with surgery was 93.3%.

Conclusion

Musculoskeletal ultrasound is a very useful tool in almost all disorders of musculoskeletal system and shall be a necessary tool of a physicians, specially a family physician, orthopedic surgeon, physiotherapist and rheumatologist.

An early change in arterial wall dynamics introduced as a novel risk factor for cardiovascular events in various populations is discussed in this review.

Distensibility of an artery segment as reflection of the mechanical stress affecting the arterial wall during the cardiac cycle has been intensively studied recent years through the technological development of high-resolution ultrasound systems.

A decrease of arterial distensibility (i.e. increase of arterial wall stiffness) seems to be a common pathological mechanism for many factors associated with cerebrovascular and cardiovascular diseases. It is difficult to define the role of each factor affecting the arterial wall motions dependent mainly on the left ventricle, intra arterial pressure and blood volume, endothelium function, smooth muscle tone and neural control mechanism. The calculations of arterial compliance, elastic modulus, augmentation pressure, stiffness and intima–media thickness may help to identify the role of each mechanism if they are based on high-tech measurements of arterial wall.

The role of nervous regulation of blood vessel's tone in this process is not clear. Our studies show the strong correlation between autonomic imbalance and increase of carotid arterial distensibility in young patients. Various possible relationships between changes in the dynamic artery wall properties and neural regulation are discussed.

Confident interpretation of image data is critical for the success of complex cases. By enabling the simultaneous live navigation of reference series, such as CT, MRI and PET, side-by-side with live ultrasound, fusion imaging enables the physician to directly correlate anatomy between modalities. This display facilitates interpretation of ultrasound and communication of findings.

Reversible cerebral vasoconstriction is a syndrome characterized by typical clinical manifestation and by the detection of vasoconstriction in cerebral arteries. Clinical symptoms are thunderclap headache, nausea, vomiting, confusion and seizures. Stenosis and dilatation of the cerebral arteries can be detected. Ultrasound as a non-invasive examination can also detect and control the findings. We describe the syndrome by reporting the case of a 32 year old primipara with vasoconstriction syndrome after preeclampsia.

Background

A limitation of transcranial Doppler (TCD) ultrasound is the inability to distinguish tiny benign bubbles from potentially hazardous particulate emboli based on analysis of the intensity of backscattered ultrasound. This study examines the Doppler characteristics of small microbubbles detected during screening of patients for a patent foramen ovale (PFO). The aim of this study was to identify unique microbubble properties that could differentiate between solid and gaseous emboli.

Methods

Bilateral TCD monitoring of the middle cerebral arteries (MCA) was performed for 34 patients during PFO screening using agitated saline. Patients were injected up to three times and asked to perform a valsalva manoeuvre. The raw audio data was recorded onto an external laptop for subsequent analysis.

Results

Eleven patients tested positive for a PFO, yielding 331 embolic signals with intensities <35 dB. The median peak measured-embolus-blood-ratio (MEBR) was 25.7 dB and the median duration was 33.0 ms. The majority of signals lasted between 12 and 92 ms, which are much longer than previously reported for particulate thrombus where the majority of signal durations are between 6 and 41 ms. Pearson correlation tests revealed a weak positive correlation between estimated microbubble velocity and signal duration (0.26, p < 0.0001).

Conclusions

Doppler signal properties were analysed for over 300 microbubbles recorded in vivo. Microbubble signal duration was found to be higher than measured for solid emboli. Further work to develop a clinically useful model based on microembolus properties to differentiate solid and gaseous is ongoing.

Background

Nowadays, more attention is paid to the potential risk factors of cerebrovascular events including some environmental conditions. We aimed to compare the long-term effects of hypobaric condition of pilots versus hyperbaric condition of divers as two possible occupational risk factors on blood flow velocity of middle cerebral and basilar arteries.

Methods

This cross-sectional study was performed in Firoozgar Hospital, Tehran, Iran between March 2009 and June 2010. A final number of 15 pilots and 16 divers were referred to the Neurology Laboratory of Firoozgar Hospital. Afterward, Transcranial Doppler ultrasonography was performed to evaluate blood flow velocity of middle cerebral (MCA) and basilar arteries.

Results

Comparison of the TCD findings between these two groups showed that resistance index was significantly higher in divers [0.57 (SD = 0.03) vs. 0.52 (SD = 0.06), P = 0.008]. A significant inverse correlation was also found between total working index of the pilots and the mean velocities (r = −0.58, P = 0.027) of right MCA even after eliminating the confounding effect of age.

Conclusion

In our report, some considerable associations were found especially with regard to the long-term effects of hyperbaric condition of divers on blood flow velocity of middle cerebral and basilar arteries using Transcranial Doppler ultrasonography. Chronic exposure to the hyperbaric condition of diving seems to have some probable effects on brain hemodynamics in the long-term which are in favor of decreasing blood flow and increasing of RI and PI.