When classical music relaxes the brain: An experimental study using Ultrasound Brain Tissue Pulsatility Imaging.

INTRODUCTION: Recent evidence suggests that biomechanical parameters of the brain, such as Brain Tissue Pulsatility (BTP), could be involved in emotional reactivity. However, no study has investigated the impact of an emotional task on BTP. We used the ultrasound method of Tissue Pulsatility Imaging (TPI) to assess changes in BTP to exciting and relaxing classical music, in a musical perception task, as a validated paradigm to assess emotional reactivity. METHODS: 25 healthy volunteers were exposed via earphones to four 5-minute musical excerpts (two exciting and two relaxing musical excerpts) presented in a randomized order and intersected by 5 silence periods. Measures of BTP, Heart Rate (HR) and Skin Conductance (SC) were collected during the entire task. RESULTS: The BTP significantly decreased with relaxing music compared to silence, and especially with the excerpt 'Entrance of the Shades' by Minkus. The HR and SC, but not Heart Rate Variability, were also decreased with relaxing music. We found no significant effect of exciting music. DISCUSSION: We report, for the first time, that classical relaxing music decreases the amplitude of the brain pulsatile movements related to cerebral blood flow and mechanical properties of the brain parenchyma, which provides further evidence of the involvement of BTP in emotional reactivity. In addition, we validate the use of TPI as a non-invasive, portable and low cost tool for studies in psychophysiology, with the potential to be implemented as a biomarker in musicotherapy trials notably.

Simultaneous acoustic stimulation of human primary and secondary somatosensory cortices using transcranial focused ultrasound.

BACKGROUND: Transcranial focused ultrasound (FUS) is gaining momentum as a novel non-invasive brain stimulation method, with promising potential for superior spatial resolution and depth penetration compared to transcranial magnetic stimulation or transcranial direct current stimulation. We examined the presence of tactile sensations elicited by FUS stimulation of two separate brain regions in humans-the primary (SI) and secondary (SII) somatosensory areas of the hand, as guided by individual-specific functional magnetic resonance imaging data. RESULTS: Under image-guidance, acoustic stimulations were delivered to the SI and SII areas either separately or simultaneously. The SII areas were divided into sub-regions that are activated by four types of external tactile sensations to the palmar side of the right hand-vibrotactile, pressure, warmth, and coolness. Across the stimulation conditions (SI only, SII only, SI and SII simultaneously), participants reported various types of tactile sensations that arose from the hand contralateral to the stimulation, such as the palm/back of the hand or as single/neighboring fingers. The type of tactile sensations did not match the sensations that are associated with specific sub-regions in the SII. The neuro-stimulatory effects of FUS were transient and reversible, and the procedure did not cause any adverse changes or discomforts in the subject's mental/physical status. CONCLUSIONS: The use of multiple FUS transducers allowed for simultaneous stimulation of the SI/SII in the same hemisphere and elicited various tactile sensations in the absence of any external sensory stimuli. Stimulation of the SII area alone could also induce perception of tactile sensations. The ability to stimulate multiple brain areas in a spatially restricted fashion can be used to study causal relationships between regional brain activities and their cognitive/behavioral outcomes.

Direct phase projection and transcranial focusing of ultrasound for brain therapy.

Ultrasound can be used to noninvasively treat the human brain with hyperthermia by focusing through the skull. To obtain an accurate focus, especially at high frequencies (>500 kHz), the phase of the transmitted wave must be modified to correct the aberrations introduced by the patient's individual skull morphology. Currently, three-dimensional finite-difference time-domain simulations are used to model a point source at the target. The outward-propagating wave crosses the measured representation of the human skull and is recorded at the therapy array transducer locations. The signal is then time reversed and experimentally transmitted back to its origin. These simulations are resource intensive and add a significant delay to treatment planning. Ray propagation is computationally efficient because it neglects diffraction and only describes two propagation parameters: the wave's direction and the phase. We propose a minimal method that is based only on the phase. The phase information is projected from the external skull surface to the array locations. This replaces computationally expensive finite-difference computations with an almost instantaneous direct phase projection calculation. For the five human skull samples considered, the phase distribution outside of the skull is shown to vary by less than λ/20 as it propagates over a 5 cm distance and the validity of phase projection is established over these propagation distances. The phase aberration introduced by the skull is characterized and is shown to have a good correspondence with skull morphology. The shape of this aberration is shown to have little variation with propagation distance. The focusing quality with the proposed phase-projection algorithm is shown to be indistinguishable from the gold-standard full finite-difference simulation. In conclusion, a spherical wave that is aberrated by the skull has a phase propagation that can be accurately described as radial, even after it has been distorted. By combining finite-difference simulations with a phase-projection algorithm, the time required for treatment planning is significantly reduced. The correlation length of the phase is used to validate the algorithm and it can also be used to provide guiding parameters for clinical array transducer design in terms of transducer spacing and phase error.

Verification of fetal brain responses by coregistration of fetal ultrasound and fetal magnetoencephalography data.

Fetal magnetoencephalography (fMEG) is used to study neurological functions of the developing fetus by measuring magnetic signals generated by electrical sources within the fetal brain. For this aim either auditory or visual stimuli are presented and evoked brain activity or spontaneous activity is measured at the sensor level. However a limiting factor of this approach is the low signal to noise ratio (SNR) of recorded signals. To overcome this limitation, advanced signal processing techniques such as spatial filters (e.g., beamformer) can be used to increase SNR. One crucial aspect of this technique is the forward model and, in general, a simple spherical head model is used. This head model is an integral part of a model search approach to analyze the data due to the lack of exact knowledge about the location of the fetal head. In the present report we overcome this limitation by a coregistration of volumetric ultrasound images with fMEG data. In a first step we validated the ultrasound to fMEG coregistration with a phantom and were able to show that the coregistration error is below 2 cm. In the second step we compared the results gained by the model search approach to the exact location of the fetal head determined on pregnant mothers by ultrasound. The results of this study clearly show that the results of the model search approach are in accordance with the location of the fetal head.

Three-dimensional sonographic calculation of the volume of intracranial structures in growth-restricted and appropriate-for-gestational age fetuses.

OBJECTIVES: To evaluate the feasibility and reproducibility of volume segmentation of fetal intracranial structures using three-dimensional (3D) ultrasound imaging, and to estimate differences in the volume of intracranial structures between intrauterine growth-restricted (IUGR) and appropriate-for-gestational age (AGA) fetuses. METHODS: Total intracranial, frontal, thalamic and cerebellar volumes were measured using 3D ultrasound imaging and Virtual Organ Computer-aided AnaLysis (VOCAL) in 39 IUGR and 39 AGA fetuses matched for gestational age, at 28-34 weeks of gestation. Volumes of, and ratios between, structures were estimated, and differences between IUGR and AGA fetuses were calculated. Volume measurements were performed by two observers, and interobserver and intraobserver intraclass correlation coefficients (ICCs) were calculated for each structure. RESULTS: Volumes were satisfactorily obtained in all fetuses. All net volumes except those for the thalamus (P = 0.23) were significantly smaller (P = 0.001) in IUGR fetuses. After adjusting volumes for biparietal diameter the frontal volume was significantly smaller (P = 0.02) and the thalamic volume significantly greater (P = 0.03) in IUGR fetuses than in AGA fetuses. Significant intergroup differences in the ratios between structures were found only in those involving the frontal region. Interobserver ICCs were as follows: total intracranial 0.97 (95% CI, 0.92-0.98), cerebellar 0.69 (95% CI, 0.44-0.75), frontal 0.66 (95% CI, 0.42-0.79) and thalamic 0.54 (95% CI, 0.37-0.72). CONCLUSIONS: IUGR fetuses show differences in the volume of intracranial structures compared with AGA fetuses, with the largest difference found in the frontal region. These differences might be explained by in-utero processes of neural reorganization induced by chronic hypoxia.

[Posttraumatic disturbances in patients with light craniocerebral injury and their correction via various variants of dynamic magnetotherapy].

Examination of 90 patients in intermediate period of slight craniocerebral injury before and after use of curative technologies with including of dynamic magnetotherapy suboccipitally or transcranially. It is established, that choosing rehabilitation methods, it is necessary to take into consideration clinical manifestation of disease, state of cerebral blood circulation, vegetative nervous system, bioelectrogenesis of cerebrum.

Preventing stroke among children with sickle cell anemia: an analysis of strategies that involve transcranial Doppler testing and chronic transfusion.

BACKGROUND: Transcranial Doppler ultrasonography can identify children with sickle cell anemia who are at elevated risk of stroke and may benefit from chronic transfusions. Uncertainty about the risk/benefit trade-offs of chronic transfusion has led some clinicians to decide not to offer transcranial Doppler ultrasonography screening. OBJECTIVES: Our goals were to (1) compare the projected benefits and risks of 6 primary stroke-prevention strategies, (2) estimate the optimal frequency of screening, and (3) identify key assumptions that influence the risk/benefit relationship. METHODS: We designed a decision model to compare 6 primary stroke-prevention strategies: (1) annual transcranial Doppler ultrasonography screening until age 16 with children at high risk of stroke receiving monthly transfusion for life; (2) annual transcranial Doppler ultrasonography until age 16 with transfusions until age 18; (3) biannual transcranial Doppler ultrasonography until age 16 with transfusions until age 18; (4) annual transcranial Doppler ultrasonography until age 10 with transfusion until age 18; (5) 1-time screening at age 2 with transfusion until age 18; and (6) no intervention. Assumptions were derived from the published literature. RESULTS: For a hypothetical cohort of 2-year-old children, the optimal strategy was transcranial Doppler ultrasonography screening annually until age 10 with children at high risk receiving monthly transfusions until age 18. The optimal strategy would prevent 32% of strokes predicted to occur without intervention. The optimal strategy led to benefits similar to more intensive screening and transfusion strategies but resulted in fewer adverse events. All the intervention strategies resulted in net losses in life expectancy, because the projected mortality averted by stroke prevention was outweighed by the projected increase in mortality from transfusion. Results were sensitive to adherence rates to iron-chelation therapy. CONCLUSIONS: The optimal stroke-prevention strategy was projected to be annual transcranial Doppler ultrasonography screening until age 10 with transfusion for children at high risk until age 18. Better adherence to chelation therapy would improve life expectancy in all intervention strategies.

Transcranial sonography and [123I]FP-CIT SPECT disclose complementary aspects of Parkinson's disease.

Hyperechogenic signal of substantia nigra (SN) in transcranial sonography (TCS) and reduced striatal uptake in FP-CIT SPECT are common findings in idiopathic Parkinson's disease (PD). But so far it is unknown whether the extent of SN hyperechogenicity represents a correlate for the degeneration of presynaptic dopaminergic neurons in PD. We performed TCS and 123I-labelled N-(3-fluoropropyl)-2ss-carbomethoxy-3ss-(4-iodophenyl)nortropane ([123I]FP-CIT) SPECT in 53 patients with PD. Striatal FP-CIT uptake was quantified by measuring the striatal/posterior lobe binding of [123I]FP-CIT. SN echogenicity was quantified by planimetric measurement of the maximum extension of hyperechogenic signals. We found no correlation between striatal FP-CIT uptake and echogenicity of the SN, neither contralateral to the clinically more affected body side (r = +0.08, P = 0.57; Pearson's correlation) nor ipsilateral (r = +0.01; P = 0.92). Our data show that the extent of SN hyperechogenicity does not correlate with the degeneration of presynaptic dopaminergic nerve terminals. Obviously SN hyperechogenicity and degeneration of presynaptic dopaminergic nerve terminals exist independently from each other and may be based on different pathomechanisms.

Treatable domain and optimal frequency for brain tumors during ultrasound hyperthermia.

PURPOSE: To examine the optimal ultrasound frequency and the treatable domain determined by the tumor size and tumor depth when an external ultrasound heating system is employed for the brain tumor hyperthermia. METHODS AND MATERIALS: This work employs a simplified model of a scanned ultrasound transducer power deposition (a cone with convergent/divergent shape) and a search algorithm to investigate the optimal frequency and the treatable domain. The distributions of temperature and SAR (specific absorption rate) ratio are used to determine the appropriateness of the acoustic window size and the input power level for a yielded set of tumor conditions. The factors considered are the acoustic window size, tumor size and depth, ultrasound frequency, and the acoustic absorption of the post-target bone behind the tumor. RESULTS: Simulation results demonstrate that the optimal frequency depends on the tumor depth and the acoustic absorption of the post-target bone. However, it is almost independent of the acoustic window size. The optimal frequency shifts to a higher level for a deeper tumor heating to reduce the effect of the high acoustic absorption of post-target bone. Moreover, the treatable domain is proportional to the acoustic window size and related to the ultrasound frequency. CONCLUSION: It may not be possible to deliver appropriate ultrasonic energy to heat a brain tumor without overheating the normal brain tissue and/or the post-target bone under the constraints of the available acoustic window size for the ultrasonic beam, ultrasonic attenuation of brain tissue, high absorption of post-target bone, and high blood perfusion rate. The results of this study can be a guideline for designing an optimal ultrasound heating system, arranging the transducers, and implementing further treatment planning for the brain tumor hyperthermia.

Ultrasound-monitored effects of acupuncture on brain and eye.

A new transcranial Doppler sonography arrangement was used to monitor blood flow profiles in the supratrochlear and middle cerebral arteries simultaneously and continuously. The technique selectively demonstrated the specific effect of acupuncture on the cranial arteries, in a 25-year-old female with pigmentary retinopathy. Stimulation of points Zanzhu and Yuyao led to a marked increase of blood flow velocity in the supratrochlear artery and to a decrease of flow velocity, in the middle cerebral artery. These acupuncture-induced effects were reproducible even though both arteries originate from the same major vessel.

[Intraventricular brain pressure in newborn infants with asphyxia and the means for its correction]. / Vnutrizheludochhkovoe davlenie mozga u novorozhdennykh s asfiksiei i sposoby ego korrektsii.

The paper deals with the information noninvasive tool of echoencephalographic determination of cerebral intraventricular pressure in the newborns. With this mode, spinal fluid pressures were measured in 80 patients with prior degrees II and III asphyxia and in 25 healthy children in the early neonatal period. To enhance the efficiency of treating the fluid-hypertensive syndrome in the newborns with hypoxically afflicted central nervous system, an atraumatic method of reflex therapy, including superficial acupuncture, metallic plate acupuncture and application has been developed and proposed if chemotherapeutical loads are restricted. Recommendations to choose acupuncture points are given and the advantages of the method are analyzed.

[The indications and limits for echographic studies in pediatrics]. / Indicatiile si limitele investigatiei echografice în pediatrie.

Echography is an non-invasive investigation with many advantages, but also with its limits. It allows diagnosis in numerous diseases and in other illness may suggest the choice of the next investigations, thus shortening considerably the diagnosis steps. The information provided by the echographic examination must be correlated with the clinical findings and other data furnished by the laboratory tests or other imagistic investigations, to obtain an integrated holistic evaluation, able to give a complete and correct final diagnosis.

[Ultrasonic dopplerography in the diagnosis of the initial manifestations of insufficiency of the blood supply to the brain]. / Ul'trazvukovaia dopplerografiia v diagnostike nachal'nykh proiavlenii nedostatochnosti krovoobrashcheniia mozga.

Sixty-eight patients with cerebrovascular insufficiency received a course of quantum hemotherapy by means of ultraviolet irradiation of the blood. The cerebral hemodynamics was evaluated by ultrasound transcranial dopplerography. It was found that this method may be used for early diagnosis as well as for the control of treatment efficacy. It was established that ultraviolet irradiation of the blood essentially effected the cerebral hemodynamics, reduces interhemispheric asymmetry, causes no cerebral steal syndromes.

Normal sonographic findings of the infant temporal lobe in coronal sections.

Coronal sonograms of the temporal lobe of the infant brain were obtained using a real time sector scanner with a 5.0 MHz transducer probe. The precise normal anatomy in the coronal sections was determined by correlating with corresponding brain specimens. It was revealed that the spatial arrangement of structures in the medial part of the temporal lobe, i.e. the hippocampal formation and the inferior horn, varied in the three different planes. In the plane through the anterior part of the temporal lobe, these structures were seen as a horizontal lamellar configuration, whereas in the plane through the middle part these structures were depicted as a typical interfolded arrangement. However, the hippocampal formation was barely visible in the plane through the posterior part.