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PubMedDate not supplied

Ultrasonographic fetal nomograms of anterior ventricular hemisphere ratio (AVHR) and posterior ventricular hemisphere ratio (PVHR) for early prenatal diagnosis of hydrocephalus.

Serial ultrasound scans were done in 150 fetuses between 14th to 22nd week of gestation to establish the nomograms of anterior ventricular hemisphere ratio (AVHR) and posterior ventricular hemisphere ratio (PVHR). Of 150 fetuses, 100 were in the high risk group for neural tube defect and 50 were in the control group. The study indicates that the value of AVHR decreases from 0.62 to 0.50 and PVHR from 0.60 to 0.50 between 14th to 22nd week of gestation. No statistical difference was observed in the values of AVHR and PVHR in high risk and low risk (control) cases (p > .001). The value of AVHR or PVHR greater than 0.5 after 18 weeks of gestation or more was considered pathological for hydrocephalus. In 2, out of 3 cases of hydrocephalus detected in our series, the value of AVHR and PVHR was 0.7 at 20 weeks and in the third case it was 0.6 at 18 weeks. All of these values were 3 SD above the normal for the period of gestation.

Cephalometry↗
PubMed1991

Transcranial Doppler sonography: nitrous oxide and cerebral blood flow velocity in children.

To determine the effect of nitrous oxide (N2O) on cerebral blood flow velocity (CBFV) and cerebrovascular resistance index (RI+) in children, ten ASA physical status I or II patients aged one to eight years old, scheduled for urological procedures, were studied. Anaesthesia was induced with thiopentone 2 mg.kg-1, fentanyl 5 micrograms.kg-1 and diazepam 0.3 mg.kg-1. Muscular relaxation was ensured by using vecuronium 0.1 mg.kg-1. After tracheal intubation, anaesthesia was randomly assigned to either a mixture of air in oxygen (N2/O2) or 70% N2O in oxygen (N2O/O2) producing an FIO2 of 30%. Three sets of measurements of CBFV and RI+ were made with both gas mixtures. The CBFV and RI+ were measured in the middle cerebral artery (MCA) with a transcranial Doppler monitor. Measurements were made while using the initial gas mixture, then the second gas mixture was administered, and finally, the patient again was given the initial gas mixture. A continuous caudal epidural or lumbar epidural block was performed before skin incision. Neuromuscular blockade was maintained with vecuronium 0.05 mg.kg-1. Temperature, heart rate, end-tidal CO2, arterial oxygen saturation, haematocrit and arterial blood pressure were maintained constant. Ventilation was adjusted to achieve normocapnia. The CBFV increased when 70% N2/O2 was replaced by 70% N2O/O2 (P less than 0.05) while the CBFV decreased when 70% N2/O2 was readministered (P less than 0.05). Likewise, the CBFV decreased when 70% N2O/O2 was replaced by 70% N2/O2 (P less than 0.05) while the CBFV increased when 70% N2O/O2 was readministered (P less than 0.05).

Anesthesia, Inhalation↗
PubMed1992

Cerebrovascular stability during isoflurane anaesthesia in children.

The aims of this study were firstly, to determine the effect of various concentrations of isoflurane on cerebrovascular circulation and secondly, to examine the time-response characteristics of the drug on cerebral blood flow velocity in anaesthetized children. Thirty-two ASA physical status I or II patients aged one to eight years and scheduled for urological surgery were studied. Anaesthesia was induced with thiopentone 5 mg.kg-1 and fentanyl 2 micrograms.kg-1. Muscle relaxation was provided with vercuronium 0.1 mg.kg-1. Tracheal intubation was performed in all cases. Anaesthesia was maintained with isoflurane in a mixture of air and oxygen to produce an inspired oxygen fraction (FIO2) of 0.3. Ventilation was adjusted to maintain normocapnia. A caudal or lumbar epidural catheter was inserted before skin incision and a continuous bupivacaine, without epinephrine, infusion established. During the first part of this study, the initial isoflurane concentration for 24 patients was randomized and age-adjusted to 0.5 MAC, 1.0 MAC, or 1.5 MAC. After steady-state was reached, the subsequent isoflurane MAC concentration was randomized by either raising or lowering it from the initial concentration. In the second part of this study, the time-response effect of isoflurane was examined. Eight patients received 1.0 MAC isoflurane over 90 to 150 min. Temperature, heart rate, and systolic blood pressure were unchanged throughout the study. Cerebral blood flow velocity (CBFV) and resistance index (RI+), a measure of cerebrovascular resistance, were measured in the M1 segment of the middle cerebral artery (MCA) with a 2 MHz transcranial Doppler monitor.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia, Inhalation↗
PubMed1993

Cerebral blood flow velocity patterns during cardiac surgery utilizing profound hypothermia with low-flow cardiopulmonary bypass or circulatory arrest in neonates and infants.

To examine the effects of low-flow cardiopulmonary bypass (CPB) and circulatory arrest (PHCA) on cerebral pressure-flow velocity relationships, we studied 32 patients (< 9 mo of age) undergoing corrective cardiac procedures. Pressure-flow velocity relationships were studied during profound hypothermia (nasopharyngeal temperature < 20 degrees C). Cerebral blood-flow velocity (CBFV) was measured in the middle cerebral artery using transcranial Doppler sonography. The anterior fontanel pressure (AFP) was measured using an intracranial pressure monitor. Cerebral perfusion pressure (CPP) was calculated (mmHg) as mean arterial pressure (MAP) minus AFP. Nasopharyngeal temperature, PaCO2 and haematocrit were controlled during the study period. Alpha-stat acid-base management was employed. The CBFV measurements were made continuously over a range of CPP as pump flow (Q) was decreased to low-flow or to circulatory arrest and again during the subsequent increase in Q and CPP to normal. As Q and CPP were increased after a period of low-flow CPB during which period detectable CBFV was present, the CBFV was greater at any given CPP than prior to the low-flow state (P < 0.05). However, after PHCA a higher CPP (P < 0.05) was necessary to re-establish detectable CBFV and at any given CPP the CBFV was less than prior to PHCA (P < 0.05). Seventeen patients underwent low-flow CPB during which CBFV became non-detectable (7 +/- 1 cm.sec-1). In 12 of these patients the pattern of recovery of CBFV was the same as that observed after low-flow CPB whereas the remaining five (29%) demonstrated a pattern of recovery identical to the ones recorded after PHCA. We conclude that after PHCA a higher CPP is necessary to re-establish and maintain detectable CBFV. Furthermore, during low-flow CPB, patients where CBFV becomes non-detectable and show a pattern of CBFV recovery similar to PHCA, cessation of cerebral perfusion must be considered.

Blood Flow Velocity↗
PubMed1993

Cerebral blood flow and cerebral blood flow velocity during angiotensin-induced arterial hypertension in dogs.

Pressure-passive perfusion beyond the upper limit of cerebral blood flow (CBF) autoregulation may be deleterious in patients with intracranial pathology. Therefore, monitoring of changes in CBF would be of clinical relevance in situations where clinical evaluation of adequate cerebral perfusion is impossible. Noninvasive monitoring of cerebral blood flow velocity using transcranial Doppler sonography (TCD) may reflect relative changes in CBF. This study correlates the effects of angiotensin-induced arterial hypertension on CBF and cerebral blood flow velocity in dogs. Heart rate (HR) was recorded using standard ECG. Catheters were placed in both femoral arteries and veins for measurements of mean arterial blood pressure (MAP), blood sampling and drug administration. A left ventricular catheter was placed for injection of microspheres. Cerebral blood flow velocity was measured in the basilar artery through a cranial window using a pulsed 8 MHz transcranial Doppler ultrasound system. CBF was measured using colour-labelled microspheres. Intracranial pressure (ICP) was measured using an epidural probe. Arterial blood gases, arterial pH and body temperature were maintained constant over time. Two baseline measures of HR, MAP, CBF, cerebral blood flow velocity and ICP were made in all dogs (n = 10) using etomidate infusion (1.5 mg.kg-1 x hr-1) and 70% N2O in O2 as background anaesthesia. Following baseline measurements, a bolus of 1.25 mg angiotensin was injected i.v. and all variables were recorded five minutes after the injection. Mean arterial blood pressure was increased by 76%. Heart rate and ICP did not change. Changes in MAP were associated with increases in cortical CBF (78%), brainstem CBF (87%) and cerebellum CBF (64%).(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin II↗
PubMedDate not supplied

The value of transcranial Doppler sonography in the differential diagnosis of Alzheimer disease vs multi-infarct dementia.

Primary degenerative dementia of the Alzheimer type and multi-infarct dementia exhibit differences in cerebrovascular blood flow velocity profiles, which were investigated by means of transcranial Doppler sonography. The pulsatility indices, as angle-independent parameters of peripheral vascular resistance, measured in middle cerebral and basilar arteries of patients with multi-infarct dementia (MID), were significantly increased (p < 0.005) with respect to cases of primary degenerative dementia of the Alzheimer type and to healthy age-matched controls. Approximately 75% of all MID patients exhibited small vessel disease rather than thromboembolism from the extracranial arteries and the heart, as judged by extracranial and transcranial Doppler sonographies, computerized cerebral tomographies, EEGs, and, if necessary, 2-D echocardiographies.

Aged↗
PubMed1997

Regional cerebral blood flow increases during preparation for and processing of sensory stimuli.

Preparing for and processing of sensory stimuli are energy-requiring processes. We attempted to assess the relative contributions of these processes to increases in regional cerebral perfusion. Nineteen healthy right-handed subjects were examined while they were engaged in detecting tactile stimuli to the index finger 5 s after a cueing tone. Cerebral blood flow velocity (CBFV) modulations in the middle cerebral arteries (MCAs) were continuously measured by bilateral simultaneous transcranial Doppler ultrasonography. Tactile stimuli well above threshold per se did not produce a significant, relative CBFV increase in the contralateral MCA. However, when subjects were expecting a threshold tactile stimulus, there was a significant regional increase in CBFV in the hemisphere contralateral to the attended index finger for approximately 15 s, starting within the first seconds after the cueing. This increase was present even before the tactile stimulus was applied and also in sessions when the stimulus was omitted. We conclude that preparation of the cortex causes a stronger regional cerebral blood flow increase than the processing of the tactile stimulus itself.

Adult↗
PubMed2003

[Present state of ultrasonographic diagnosis of temporal arteritis. Results of a prospective study].

Temporal arteritis (TA) is a treatable systemic vasculitis with particular affinity for the temporal and orbital arteries. In a prospective study of 115 patients, we evaluated the diagnostic contribution of duplex sonography of the superficial temporal (STA), okzipital (OCCA), and carotid arteries and Doppler sonography of the supratrochlear artery (DSASTR) in patients suspected of having TA. Forty-seven patients had TA: in the STA, periarterial hypoechogenic tissue (halo) was found in 60% (OCCA 48%) and halo and stenosis in 19% (OCCA 15%) of the TA patients and in 4% of patients with other diseases. The DSASTR was abnormal in 13% of the TA patients. Arteriosclerotic carotid disease was found in 72%, >50% stenosis in 13% of the TA patients. Duplex sonography of the STA reached a diagnostic sensitivity/specificity of 78/96% compared to diagnosis and 91/82% compared to histology. In the STA/OCCA, duplex sonography is a helpful new atraumatic method for the diagnosis of TA, and DSASTR is helpful in detecting TA of the orbital arteries.

Aged↗
PubMed2001

[Harmonic imaging. A new method of ultrasound imaging of brain perfusion].

In this review, methodological aspects of cerebral perfusion imaging with ultrasound contrast agents are described. The various experimental concepts contributing to an understanding of the phenomena are summarised and the resulting investigation techniques on patients are illustrated. By means of harmonic imaging, human cerebral perfusion can be depicted as a two-dimensional scan. The two major principles of contrast measurement are analysis of the bolus kinetics and analysis of the refill kinetics. Using the bolus method, hypoperfused areas in stroke patients can be visualised and parameter images of wash-in and wash-out curves can be generated off-line. The recently developed theory on the refill kinetics of UCA enables us to calculate parameters for describing the cerebral microcirculation, as they are less affected by the depth dependence of the contrast effect. These parameters can also be visualised as images. The ultrasound methods described in this article represent new minimally invasive bedside techniques for analysing brain perfusion. Although their development is still in an early stage, the potential of these ultrasound technologies to compete with perfusion CT, perfusion MRI, and SPECT in the diagnostic arsenal of brain imaging techniques is becoming evident.

Animals↗
PubMed2003

[Advances in pediatric sonography].

Advances in the field of ultrasound technology and ultrasound contrast media over the past few years have also brought major improvements to pediatric sonography. Accordingly, contrast-enhanced voiding urosonography has become a valuable alternative in the diagnosis of vesicoureteral reflux. It is possible to achieve significant reduction in radiation exposure replacing the conventional radiologic methods used for reflux diagnosis with contrast-enhanced ultrasound. Through the introduction of harmonic imaging, an ultrasound scanning modality with high spatial and contrast resolution has become available. The modality was initially propagated as one to be applied in difficult-to-scan adults. However, initial experiences in pediatric applications are demonstrating the significant improvement it can bring in the ultrasound image quality, for example, in intestinal ultrasound. A further development is three-dimensional [3D] imaging using ultrasound. 3D-ultrasound not only offers an improvement in diagnosis but also in the acceptance of ultrasound in interdisciplinary work and teaching. The first applications of 3D-ultrasound in pediatrics are focusing on brain ultrasound and volume measurement of the kidneys.

Child↗
PubMed2007

[Sturge-Weber syndrome. Early manifestation and visualization of disease course].

BACKGROUND: The purpose of this study was to evaluate ultrasound, MRI, and CT investigations in children with Sturge-Weber syndrome. PATIENTS AND METHODS: From 1996 to 2005, a total of 15 investigations of the brain performed in 6 children with Sturge-Weber syndrome were reviewed. We evaluated four ultrasound, five CT, and six MRI exams. RESULTS: With ultrasound an increase of the echogenicity of the periventricular white matter was depicted in the first days of life. MRI is the best modality to demonstrate the vascular malformation, the impaired cerebral venous drainage, and the atrophy of one hemisphere. CONCLUSIONS: One-sided periventricular hyperechogenicity on ultrasound can be an early sign of Sturge-Weber syndrome in children with a nevus flammeus. MRI is the method of choice to diagnose Sturge-Weber syndrome and to follow up these children if the neurological status of the patients changes.

Adolescent↗