A study in children with headaches associated mainly with venous hemodynamic disturbances has been performed. The role of cerebral venous disturbances has been defined in children with structural cerebral abnormalities: craniovertebral junction anomalies (Chiari abnormalities I) and hypoplasia of cerebral venous sinuses. Disturbances of cerebral hemodynamics revealed by ultrasonic methods determine the management of patients with different cerebral venous abnormalities.
Sonothrombolysis using diagnostic ultrasound (US) in combination with microbubble (MB) contrast agents is an attractive trial. Superheated perfluorocarbon nanodroplet (SPN), which can turn into MBs upon US trigger, may have advantages in sonothrombolysis. As a preliminary investigation of SPN-assisted sonothrombolysis, we performed a safety evaluation in vivo.
Twenty male rabbits (2.59 ± 0.14 kg) were assigned to three groups: the Control group (n = 6), 2.2 mL/kg of physiological saline intravascular (i.v.) injection into auricular vein; the PL group (n = 8), 25 mg/kg of phospholipid-coated SPN i.v.; and the AA group (n = 6), 25 mg/kg of SPN coated with poly aspartic acid derivative i.v. Rectal temperatures were maintained at 39.08 ± 0.98 °C. Neurological evaluation and biochemical blood examinations were performed at pre-injection, 1, 4, and 7 days after injection. Organ samples including heart, lungs, liver, spleen and kidneys were harvested after euthanasia.
Within an hour after administration of SPNs, both the PL and AA groups showed a reversible change in respiration. One animal in the AA showed transient nystagmus about 20 min after administration; however, there was no pathological damage. One animal in the PL died 2 days after. No histological damage was found in any organ sample from any of the animals. Moreover, no significant differences were found in the biochemical blood examination between the PL, AA, and Control groups.
No neurological damage or histological change was found with two SPNs. We will further investigate the SPN-assisted sonothrombolysis based on the 500-kHz US exposure with bubble liposome acceleration of rt-PA efficacy.
To demonstrate diagnostic abilities of space–time (4D) ultrasound imaging in patients with eye pathology and some neuro-ophthalmic syndromes.
Fifteen healthy controls and 15 patients with eye pathology (papilledema, retinal detachment, macular degeneration and intraocular metastasis) were studied by multimodal (color duplex, B-flow and 3D/4D imaging) sonography.
Normal optic disc resulted in a smooth and sharp contour without swelling. Papilledema was presented as a hyperechoic prominence into the vitreous. On its side the optic sheath diameter was increased in association with the degree of optic disc swelling. The retinal detachment was imaged as a hyperechoic undulating membrane, the neovascular macular degeneration – as a hyperechoic membrane behind the retina, and the intraocular metastasis – as irregular unifocal formation into the vitreous.
The 4D neuro-ophthalmo-sonology helps for the quick and non-invasive volume imaging of the type, size, location and severity of optic disc and optic nerve edema and its differentiation from other types of eye lesions.
The aim of this preliminary study is to evaluate the hypothesis of a possible causal link between the anatomical findings of vertebral artery hypoplasia (VAH) and the incidence of posterior circulation stroke. We used full ultrasonographic examination to evaluate patients with stroke in the vertebrobasilar circulation territory over a period of 1.5 years. The diameter equal or less than 2.5 mm (in V1 and V2 segment of the vertebral artery) was set as a feature of vertebral artery hypoplasia. Magnetic resonance imaging and angiography (MRI and MRA) or computed tomography and angiography (CT and CTA) were performed to confirm the anatomic variation of hypoplasia and the site of the cerebral ischemic territory. In the group of 44 stroke patients, 9 (20%) had a hypoplastic vertebral artery and 35 (80%) were without VAH. Although vertebral artery hypoplasia in previously published literature is seldom shown as a leading risk factor for stroke in vertebrobasilar (posterior) circulation, its occurrence is not negligible and in coexistence with known risk factors of stroke may increase the negative clinical impact. Vertebral artery hypoplasia can be diagnosed non-invasively with duplex ultrasonography. It is therefore a useful method for detection of this anatomic variation and for follow-up examination.
Cerebral hyperperfusion syndrome (CHS) after carotid endarterectomy (CEA) is a potential life-threatening disease. Identification of patients at risk for CHS commonly takes place with use of intra-operative transcranial Doppler (TCD), but is associated with both false positive and false negative results. We aimed to determine the diagnostic value for predicting CHS, by adding a TCD measurement in the early post-operative phase after CEA.
We retrospectively included 72 patients who underwent CEA between January 2004 and August 2010 and in whom both intra- and post-operative TCD of the ipsilateral middle cerebral artery monitoring were performed. Twelve patients (17%) had an intra-operative mean blood flow velocity (Vmean) increase >100% and 13 patients (18%) a post-operative Vmean increase of >100%. In 5 patients (7%) CHS was diagnosed; 2 of those had an intra-operative Vmean increase of >100% and all 5 a post-operative Vmean increase >100%. This results in a positive predictive value of 17% for the intra-operative and 38% for the post-operative measurement.
In conclusion, a post-operative increase of the mean velocity in the ipsilateral middle cerebral artery of >100% as measured by TCD is superior to an intra-operative velocity increase, for the identification of patients at risk for the development of CHS after CEA.
Since the first discovery, that ultrasound can overcome the skull allowing examination of the intracranial blood-flow as well as the first description of substantia nigra (SN) signal alterations via B-mode sonography, a plethora of applications especially in the field of movement disorders have been fostered. Up to now, however, most studies investigated adult individuals, even though numerous of the diseases studied have their onset already during childhood or adolescence. This overview summarizes recent studies of transcranial B-mode sonography (TCS) within the movement disorder field and outlines potential implications for pediatric applications.
Multiple sclerosis (MS) is a chronic inflammatory and neurodegenerative disease of the central nervous system (CNS). Its autoimmune origin has been recently challenged by a substantially different mechanism termed chronic cerebrospinal venous insufficiency (CCSVI), which has attracted worldwide attention in the scientific community, in the media and among MS patients. According to this hypothesis, a congestion of cerebrovenous outflow induces an increased intracranial pressure and a disintegration of the blood–brain barrier in perivenular regions promoting local iron deposition and activation of pro-inflammatory factors, ultimately leading to MS. After the initial report of a perfect association between CCSVI and MS, different independent groups were not able to replicate these results, casting doubts on the credibility of the CCSVI concept in MS. In spite of this, interventional procedures like venous angioplasty named the “liberation” treatment have been claimed as a cure of MS or at least as a major improvement of MS symptoms. As a result, an increasing number of MS patients are undergoing endovascular treatment, in spite of a lack of an evidenced-based benefit and recent reports of serious adverse events. This review represents a critical appraisal of the CCSVI hypothesis, discusses its basis, the diagnostic criteria and its relationship with MS.
Small cerebral vessels respond to variations of cerebral perfusion pressure (CPP) by changes of vessel diameter inducing changes of blood flow resistance and keeping cerebral blood flow constant. This mechanism is called cerebral autoregulation (CA). Recently stronger reactions of CA during pressure increase than during decrease were reported. Aim of this study was to assess the symmetry behavior of CA during spontaneous CPP changes and compare it to cerebrovascular pressure reactivity (CVR).
In 238 patients with traumatic brain injury or stroke, correlation indices between CPP and cerebral blood flow velocity (CBFV) were calculated during periods of increasing (upMx) and decreasing CPP (downMx). The indices range from −1 to +1, values ≤0 indicating intact, values >0 indicating impaired autoregulation. Similar correlation between arterial blood pressure (ABP) and ICP was calculated during increasing (upPRx) and decreasing ABP (downPRx), negative values indicating intact, positive values indicating impaired CVR. Only recordings with strong pressure changes (CPP/ABP > 10 mmHg) were evaluated.
CA was assessed in 62 patients. On average (mean ± SD) upMx was 0.06 ± 0.52, downMx was 0.15 ± 0.55 (P < 0.005). CVR was assessed in 47 patients. On average upPRx was 0.45 ± 0.43, downPRx was 0.38 ± 0.48 (P < 0.05). In 40 patients both Mx and PRx were calculated. On average upMx was 0.21 ± 0.55 and downMx was 0.27 ± 0.56 (P = 0.05), upPRx was 0.35 ± 0.43 and downPRx was 0.27 ± 0.47 (P < 0.05).
During pressure increase the autoregulatory response was significantly stronger than during decrease, while in contrast the cerebrovascular reactivity was significantly weaker. The reason for this opposed behavior remains unclear and needs further exploration.
This contribution summarizes the past and present status of ultrasound-facilitated thrombolysis (sonolysis) with and without the use of microspheres. Different ultrasound techniques are addressed and advantages as well as pitfalls are discussed.
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