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At least 523 records · Page 29Linked to original sources
PubMed1995

Ultrasonography in acute interstitial laser irradiation of the pig brain: preliminary results.

In this preliminary study, the use of real-time ultrasonography to visualize the effects of acute interstitial Nd:YAG laser irradiation was investigated in the normal pig brain. In six pigs, a craniotomy was performed. In the frontal or temporal lobe, a thermal laser lesion was made using a 600-micron-diameter optical fiber at powers of 1 W, 2 W, and 4 W with exposure times of 5 min and 10 min. Ten to thirty minutes after laser irradiation, the pigs were sacrificed. Ultrasound imaging was performed before, during, and after laser irradiation. During laser irradiation, a clear hyperechogenic area was observed around the fiber tip. The onset of the changes and the extent of the lesion were dependent on the power and exposure time. Histologic examination showed thermal lesions consisting of coagulation necrosis and edema. The size of the lesions correlated well with size on ultrasound imaging. The maximal lesion dimension was 12 mm in diameter (4 W for 5 min). In conclusion, within the limitations of this experimental setup, it is feasible to visualize interstitial laser-induced lesions in the brain by ultrasonography. This method is safe and simple and may be helpful in future applications of interstitial thermotherapy in brain tissue.

Animals↗
PubMed2001

Prenatal cocaine exposure and cranial sonographic findings in preterm infants.

PURPOSE: Prenatal cocaine exposure has been linked with subependymal hemorrhage and the formation of cysts that are detectable on cranial sonography in neonates born at term. We sought to determine if prenatal cocaine exposure increases the incidence of subependymal cysts in preterm infants. METHODS: We retrospectively reviewed the medical records and cranial sonograms obtained during a 1-year period on 122 premature (< 36 weeks of gestation) infants. Infants were categorized into 1 of 2 groups: those exposed to cocaine and those not exposed to cocaine. Infants were assigned to the cocaine-exposed group if there was a maternal history of cocaine abuse during pregnancy or if maternal or neonatal urine toxicology results were positive at the time of delivery. RESULTS: Five of the 122 infants were excluded from the study because of insufficient medical and drug histories. The incidence of subependymal cysts in the 117 remaining infants was 14% (16 of 117). The incidence of subependymal cysts in infants exposed to cocaine prenatally was 44% (8 of 18) compared with 8% (8 of 99) in the unexposed group (p < 0.01). CONCLUSIONS: We found an increased incidence of subependymal cyst formation in preterm infants who were exposed to cocaine prenatally. This result is consistent with results of similar studies in term infants.

Brain Diseases↗
PubMed1993

Acalvaria: a unique congenital anomaly.

Acalvaria is a rare malformation usually regarded as a postneurulation defect. It consists of absence of the calvarial bones, dura mater and associated muscles in the presence of a normal skull base and normal facial bones. The condition is frequently confused by prenatal ultrasonography with anencephaly or an encephalocele. Whereas the cerebral hemispheres are absent in anencephaly, the cranial contents in acalvaria are generally complete, though some neuropathological abnormality is often present. The presumed pathogenesis of acalvaria is faulty migration of the membranous neurocranium with normal placement of the embryonic ectoderm, resulting in absence of the calvaria but an intact layer of skin over the brain parenchyma. We describe 2 cases of acalvaria, one misdiagnosed ultrasonographically as an occipital encephalocele prenatally. The brain in one fetus demonstrated semilobar holoprosencephaly and micropolygyria, but in the other, was structurally and histologically normal with the exception of hydrocephalus.

Abortion, Therapeutic↗
PubMed2007

Anophthalmia-plus syndrome: a clinical report and review of the literature.

We describe a term male infant of healthy non-consanguineous parents, born with congenital malformations, including bilateral cleft palate and lip, mild microphthalmia with iris coloboma and glaucoma of the right eye, and blepharophimosis with severe microphthalmia of the left eye. Spine radiograph and MRI showed first sacral hemivertebra with spina bifida, and agenesis of the 2nd, 3rd, 4th, and 5th sacral vertebrae and coccyx. Spine MRI showed caudal tethering of spinal cord at L(3) level, filum terminalis lipoma and a syringomyelia. Brain ultrasound and MRI showed hypoplasia of corpus callosum with mild dilatation of the lateral ventricles. Orbital MRI showed bilateral microphthalmia-distorted small left eyeball with posteriorly located lens, and a split vitreous body in the right eye, suggestive of primary hyperplastic vitreous. The karyotype was normal. Summary of the findings in nine cases (our case and eight published cases) support the notion that anophthalmia-plus syndrome (APS) is a distinct syndrome. Gene locus of APS is yet to be identified.

Abnormalities, Multiple↗
PubMed1983

Limitations of ultrasound in detecting cerebral ischemic lesions in the neonate.

Ultrasound scans of three newborn infants with cerebral ischemic lesions demonstrated on computed tomographic scan showed unexpected changes in echogenicity of brain parenchyma in addition to lateralized mass effect. Areas of increased echogenicity were present adjacent to regions of infarction identified on computed tomographic scan. The findings suggest that caution should be exercised in the interpretation of echo-dense areas in unusual locations for hemorrhage in infants at risk for cerebral ischemic lesions.

Asphyxia Neonatorum↗
PubMed1984

Value of ultrasound for identification of acute hemorrhagic necrosis of thalamus and basal ganglia in an asphyxiated term infant.

An infant with profound intrapartum and postpartum asphyxia demonstrated striking bilateral echodensities in the region of the thalamus and basal ganglia on ultrasound scan. Neuropathological examination confirmed the presence of symmetrical areas of hemorrhagic necrosis involving the thalamus, caudate, putamen, and globus pallidus. The findings demonstrate the value of ultrasonography in the identification of this variety of perinatal hypoxic-ischemic injury.

Asphyxia Neonatorum↗
PubMed1989

Intraventricular hemorrhage in the premature infant--current concepts. Part II.

Diagnosis of periventricular-intraventricular hemorrhage (IVH) and its neuropathological consequences and accompaniments in the living infant has been facilitated greatly by the introduction of real-time cranial ultrasonography. The major advantages of the technique include high-resolution capability, portable instrumentation, lack of ionizing radiation, and relative affordability. Prognosis in infants with IVH relates to the mechanisms of brain injury, the most important of which are prior hypoxic-ischemic insults, posthemorrhagic hydrocephalus, and periventricular hemorrhagic infarction. The last of these is most critical and it is now clear that careful quantitative assessment of the ultrasonographic appearance of the periventricular parenchyma in the infant with IVH during the acute period of illness is of major value in estimating outcome. Prevention of IVH remains the most important goal. Prenatal interventions include prevention of premature birth (currently a very elusive goal in the United States), transportation of the premature infant to a tertiary facility in utero rather than after birth (an approach of proven value), prenatal administration of phenobarbital or vitamin K (initially promising data that require confirmation and amplification), and optimal management of labor and delivery. Postnatal interventions include careful resuscitation of newborns, correction of fluctuating cerebral blood flow velocity, correction or prevention of other major hemodynamic disturbances, and correction of abnormalities of coagulation. Of these interventions the use of muscle paralysis to correct fluctuating cerebral blood flow velocity has shown the most striking benefit vis-à-vis prevention of IVH. Postnatal pharmacological interventions that have been studied in detail include the use of phenobarbital, indomethacin, ethamsylate, and vitamin E. No single agent among this group has been shown consistently to lead to a decrease in incidence and severity of IVH.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebral Hemorrhage↗
PubMed1991

Cerebral blood flow velocities by transcranial Doppler during parabolic flight.

Microgravity is produced for 20 to 30 seconds in NASA's KC-135 aircraft at the end of a 2 G pullup for each of 40 parabolas per flight. Continuous transcranial Doppler ultrasound, arterial blood pressure, and acceleration levels were recorded for 12 male and 8 female healthy subjects without known cardiovascular or cerebrovascular disease. Recordings were made throughout 10 parabolas per subject in each of the supine, sitting, and standing postures. The data were digitized for off-line analysis using Fast Fourier Transform and other signal processing methods. A phase lag in changes to transcranial Doppler waveforms from the onset of acceleration was more pronounced in the standing position than in the sitting position. There was less of a phase lag in the supine position. These ultrasound changes preceded the more delayed variations in arterial blood pressure. The KC-135 provides a unique short-term environment that allows measurement of the human response to variations in acceleration but limits physiological monitoring of responses to a steady state of microgravity.

Acceleration↗
PubMed2003

Isolated cardiomegaly in the second trimester as an early sign of fetal hydrops due to intracranial arteriovenous malformation.

We report the case of a 27-year-old pregnant woman in whom isolated mild fetal cardiomegaly, diagnosed prenatally on sonographic examination at 22 weeks' menstrual age, was the first sign of development of an arteriovenous malformation of the vein of Galen. The arteriovenous malformation was visualized on sonographic examination at 29 weeks' menstrual age; prenatal MRI at 32 weeks confirmed the diagnosis. At 34 weeks' menstrual age, repeat sonographic examination demonstrated polyhydramnios, cardiomegaly, and generalized hydrops with ascites and pleural effusion. After vaginal delivery, the male neonate died of respiratory distress. We present the findings of prenatal gray-scale, color Doppler, and power Doppler sonography; MRI; and postmortem examination.

Cardiomegaly↗
PubMed2003

Mirror-image artifact mimicking epidural hematoma: usefulness of power Doppler sonography.

During sonographic examination, a mirror-like interface can scatter the ultrasound beam, producing mirror-image artifacts. We describe a case of bilateral parietal cephalhematoma in the parietal region of a 2-day-old neonate that mimicked bilateral epidural hematoma on routine sonographic examination. Forceps had been used during delivery, and the neonate had been experiencing episodes of apnea since birth. Gray-scale coronal sonograms showed anechoic structures resembling epidural hematomas in the left and right parietal regions. However, color and power Doppler sonography showed normal vascular findings, thus permitting identification of the mirror-image artifact.

Artifacts↗
PubMed1975

An ultrasound receiver with programmable time gain control.

An ultrasound receiver with programmable time gain control (TGC) has been developed. The TCG curve is synthesized from sequentially gated analog switches, each of which controls receiver gain over a range of 1cm. Diagnostic studies using a receiver with the programmable TGC curve show improved results in the amplitude equalization of received echoes and in the output display.

Echocardiography↗
PubMed1975

Midline sagittal sonographic evaluation of the midbrain.

A technique has been developed for the A-mode display of the upper brain stem using certain bony landmarks to guide transducer placement. Normal findings were substantiated at the time of penumoencephalography and angiography in order to determine the anatomic origin of the ultrasound reflections. Findings in patients with mass lesions distorting the upper brain stem will also be reported.

Adolescent↗