Biomedical subjects
Publications and source records attributed to D Schellinger.
Eleven patients with gliomas in the optic chiasm were studied using a 0.5 Tesla superconducting system and third generation computed tomography scanners. All tumors were identified with both modalities, but in the majority of cases, the posterior extension of the tumor and its relationship to adjacent brain, important to both prognosis and management, were shown better by magnetic resonance imaging.
This article, say the authors, serves as a reminder that the posterior articulations of the lumbar spine are key elements in the production of low back pain and sciatica.
Duplex sonography was used to evaluate the cranial contents of 75 infants. The first 35 were scanned to establish technique and evaluate basic flow patterns. All cranial vessels scanned in healthy term infants produced diphasic (low-resistance) waveforms, although certain cerebral vessels had characteristic Doppler signatures. The pericallosal, callosomarginal, anterior cerebral, basilar, middle cerebral, and internal carotid arteries and the vein of Galen were isolated and evaluated in almost every subject. In the second part of the study duplex characteristics of healthy term infants, healthy preterm infants, preterm infants with intracranial hemorrhages, and hydrocephalic infants were evaluated. Relative flow velocity at peak systole and end diastole and pulsatility index were investigated. The most significant variable was gestational age. Preterm infants frequently had no forward flow during diastole. Duplex sonography does not appear to add significant diagnostic information to routine real-time cranial studies. It does, however, permit more exact evaluation of cerebral blood flow than does non-pulse-gated, nondirected Doppler scanning.
Serial cranial sonograms of 55 neonates with large perinatal intraventricular/intraparenchymal hemorrhages and moderate-to-severe posthemorrhagic hydrocephalus were reviewed. In all 55 patients, the ventricles were initially enlarged and filled with anechoic cerebrospinal fluid, which contained discrete hyperechoic fragments of hematoma. Between 7 and 25 days after the initial hemorrhagic episode, however, diffuse, low-level echogenicity appeared in the ventricles of 34 patients. The low-level echogenicity was transient and persisted for 7-59 days (average, 18 days). In 32 patients, low-level echogenicity was a benign finding associated with prior intraventricular hemorrhage. In two patients, the low-level echogenicity was associated with ventriculitis. Low-level echogenicity appeared, increased, then cleared, but reappeared with the onset of ventriculitis in these two patients. Thickening of the ependyma and abnormal periventricular echogenicity, signs of inflammation, were also present. Although low-level echogenicity may commonly be a benign finding, the possibility of ventriculitis should not be ignored.
A case is described in which incorrect preliminary programming of a computerized tomography (CT) machine caused transposition of the left- and right-side indicators in a CT scan, which led to craniotomy on the normal side. The possible mechanism for this is incorrect pre-scan programming of the CT scanner with respect to patient positioning in the scanner gantry. This error, although unlikely, is still possible with the present generation of CT scanners.
Both carotid bifurcations were examined in 353 patients over a 20-month interval using a combination of real-time and pulsed Doppler ultrasound (duplex scanning). Angiographic correlation was available in 72 cases. Stenosis of the internal carotid was evaluated using a Doppler input frequency of 5 MHz and a scan angle of 60 degrees. A peak frequency shift of less than 3.5 kHz was found to be a sign of less than or equal to 30% stenosis; 3.5-4 kHz with moderate turbulence suggested 31-50% stenosis, 4-8 kHz 51-90% stenosis, and greater than 8 kHz greater than 90% stenosis. Subtotal stenosis (greater than 95%) was manifested by a frequency shift of less than 8 kHz, but the waveform was totally distorted. Overall accuracy improved from 77% for the first 6 months to 87% for the last 14 months. For stenosis greater than 50%, sensitivity improved from 82% to 97% during this period. Analysis of errors and suggestions for avoiding them are presented.
This study reports the sonographic and computed tomography (CT) findings in seven infants and neonates with intracranial calcifications and a spectrum of underlying disorders, including toxoplasmosis, cytomegalic inclusion disease, transverse/straight sinus thrombosis, and probable anoxia. Neurotropic infectious disease usually produced clumped or subependymal calcifications accompanied by sometimes bizarre ventricular configurations and prominent periventricular cystic encephalomalacia. Sonography failed to identify prospectively intracranial calcifications in two of the three patients without infection, although calcifications were visible in retrospect. Overall, CT provided optimum visualization of intracranial calcifications.
Metrizamide, a nonionic, water-soluble contrast medium, has been increasingly used for myelography. We saw a patient with cortical blindness, seizure, organic psychosis, and asterixis after undergoing attempted metrizamide myelography via C1-2 puncture. Computed tomography demonstrated early penetrance of metrizamide into the brain parenchyma, most prominently in the occipital lobes. A mechanism of direct metrizamide neurotoxicity was proposed.
Computed tomographic (CT) scans of muscle in 35 patients with neuromuscular diseases showed distinct patterns in nerve and muscle diseases. Neural diseases first showed as muscle atrophy, with decreased density in the muscles occurring later in the course of disease. Primary muscle diseases showed early decreased density in the muscles, with atrophy occurring later. The CT scan allows objective assessment of muscle mass and may be used to help select muscles for biopsy.
This article reviews the uses of arteriography, venous digital subtraction angiography, and duplex carotid sonography in the evaluation of patients with an asymptomatic carotid bruit or carotid system transient ischemic attack. It concludes with a description of the authors' guidelines for their use.
This article focuses on low back pain which is directly related to the spinal axis and its supporting structures (spondylogenic back pain). This type of back pain is particularly prominent in our society, is frequently managed surgically, and has benefited from most advanced diagnostic imaging with computed tomography.
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Speech and language development is a sensitive and important diagnostic tool for the family physician. Speech defects and delayed speech and language development can be the presenting evidence for neurologic abnormalities, cognitive difficulties and abnormal hearing. They can also be signs of emotional, social, family and behavioral problems. Finally, they can signify the need for evaluation of abnormalities of tracheal and laryngeal function and oral-motor development.
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Intracranial sonographic evaluation of the normal neonate frequently reveals an echogenic halo about the lateral ventricles. This periventricular halo is seen to varying degrees when scanning in both semiaxial and parasagittal planes in almost all normal infants. Among 180 consecutive premature neonates scanned serially with real-time sonography, two were prospectively diagnosed as having a form of periventricular echogenicity that was abnormal and represented periventricular hemorrhage. This hemorrhage completely surrounded the lateral ventricles and was intensely echogenic, as echogenic as the choroid plexus. This abnormal periventricular echogenicity was reproducible from multiple scan planes and hemorrhage was confirmed by computed tomography (CT). By contrast, CT scans obtained on another 53 of the 180 premature infants failed to reveal evidence of any abnormality corresponding to the periventricular echogenicity. Both neonates with periventricular hemorrhage developed bilateral multiseptate areas of porencephaly as sequelae to their hemorrhages. The differentiation between normal periventricular echogenicity and periventricular hemorrhage therefore attains great significance to the sonographer.
The authors ultrasonographically identified abnormalities of the posterior fossa associated with meningomyelocele (Arnold-Chiari type II malformation), Dandy-Walker malformation, extracerebellar hemorrhage, and post-hemorrhagic enlargement of the fourth ventricle. Normal anatomic and pathologic features of the posterior fossa are illustrated, and the use of realtime ultrasonographic sector scanning in the posterior fossa is discussed.
Four patients with hemangiopericytoma were examined with gray-scale sonography. Three of these patients were also evaluated by computed tomography (CT). The sonographic findings included well-defined, predominately cystic masses in two patients, a mixed solid and cystic mass in one, and a solid mass with shadowing in another. One hemangiopericytoma changed in sonographic appearance from cystic to solid following radiation. CT identified well-circumscribed masses in all three cases, but added little beyond what was seen on plain radiographs. Sonography may define the limits of a hemangiopericytoma, give information about the internal structure, and offer a way of following response to therapy. However, the sonographic features are varied and the often cystic nature of these tumors may be misleading.
Ninety-four low-birth-weight neonates were screened consecutively with real-time sonography for evidence of cerebroventricular hemorrhage. Among them, 13 were found to have intraparenchymal hemorrhage beyond the area of the germinal matrix. Weekly follow-up sonograms revealed progression to porencephaly in every surviving infant. Four different sonographic patterns were observed during the evolution from the original hemorrhage to the porencephalic cyst. The size of the mature porencephalic cyst correlated directly with the size of the intraparenchymal hemorrhage. After ventriculoperitoneal shunting, the porencephalic cysts became smaller or remain unchanged. One small cyst was no longer identified after successful shunting, but reappeared with shunt failure.