Biomedical subjects
Publications and source records attributed to D Schellinger.
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.
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Thirty-three low-birth-weight neonates were diagnosed prospectively as having an intraventricular hemorrhage, using a real-time sonographic sector scanner. Ultrasound findings were corroborated in 27 patients by computed tomography (CT) or autopsy. Intraventricular blood is hyperechoic and, in a fresh hemorrhage, a continuous cast-like pattern of increased echogenicity replaces the usually minute, echo-free lateral ventricles. After one to three days, the lateral ventricles begin to enlarge around the echogenic clot if hydrocephalus complicates the hemorrhage. The sonographic findings indicating intraventricular hemorrhage and its progression to hydrocephalus are presented. The accuracy of sonographic real-time sector scanning in the evaluation of neonatal intraventricular hemorrhage is discussed and compared to CT.
Fifty neonatal and infant heads were examined using a 5 MHz real-time sector scanner. Anatomic detail superior to that previously described was achieved by this method. Normal structures routinely imaged included the entire ventricular system and many parts of the subarachnoid spaces. The gray scale detail of parenchymal structures was usefully demonstrated. Routinely visualized vascular structures included the anterior cerebral artery system, the middle cerebral arteries, the choroid plexus, and the posterior cerebral arteries. Hydrocephalus, as well as intraventricular hemorrhage and its sequelae, were investigated. Computed tomography (CT) is considered diagnostic in hydrocephalus and intraventricular hemorrhage, but evaluation by sonography compares favorably. Among other advantages of sonography are the feasibility of bedside scans without removing the patient from the intensive care nursery and the elimination of ionizing radiation.
The interpretation of postshunt computed tomographic (CT) scans of hydrocephalic patients presents numerous difficulties unless the interpreter has a thorough knowledge of the clinical symptoms, type and cause of hydrocephalus, preshunt morphology of ventricles and subarachnoid spaces, possible complications of shunt placement, and signs of shunt failure. A review of 368 scans from 108 hydrocephalic patients included subgroup statistical analysis of the development of ventricular asymmetry and of subarachnoid space changes after shunting. The situation and appearance of ventricular catheters were quite variable. Subarachnoid space enlargement after shunting usually was related to long-standing high-grade ventriculomegaly, and was observed most commonly in congenital or acquired nonneoplastic hydrocephalus with little relationship to the site of blockage. Ventricular asymmetry developed in one third of the cases and was related to the site of the shunt catheter tip. Preshunt asymmetry persisted in spite of shunt placement in the larger ventricle. Accurate diagnosis of shunt failure usually required baseline CT studies, correlation with clinical findings, and, in some cases, serial scans.
A new CT pattern was observed in 2 patients with adrenoleukodystrophy (ALD). This pattern, which the authors call Type II, is characterized by the absence of posterior periventricular areas of decreased attenuation around the trigone on non-contrast scans: after contrast infusion, however, there is striking enhancement of various white-matter structures (tracts or fiber systems) such as the internal capsules, corpus callosum, corona radiata, forceps major, and cerebral peduncles. This is different from numerous previous descriptions of the CT pattern in ALD. Type II ALD does not appear to have been seen in any other leukoencephalopathy and is probably specific for a phenotypic variant or an evolving stage of ALD.
Computed tomography (CT), ultrasound, radionuclide scans, and plain abdominal radiographs of 25 patients with biliary-enteric anastomoses were reviewed for manifestations of gas in the biliary tree. Patients with biliary-enteric anastomoses are frequently being followed for metastatic disease in the liver. The majority of these patients have free reflux of air into the biliary duct system (pneumobilia). The typical findings of gas in the biliary tree are discussed as seen on each of the aforementioned modalities. The differentiation between findings attributable to pneumobilia itself and those secondary to actual metastatic disease are stressed. There were no discrepancies between radionuclide, CT, and ultrasound diagnoses of liver metastases.
In this paper we present our experience with computerized tomographic imaging of the pancreas, both in normal and abnormal conditions. Eighty patients were studied for evaluation of pancreatic disease. A further 50 patients, all with a normal pancreas, were studied for abnormalities of other abdominal organs and served as the control group. Helpful signs in establishing the diagnosis of carcinoma of the pancreas were mass effect within the pancreas, alteration of organ contour and obliteration of retroperitoneal fat planes. We found that differentiation from pancreatitis or retroperitoneal lymphadenopathy may at times be difficult. Our results showed that in 22 out of 23 patients with proven normal pancreas, the pancreas size on the CT display was within the adopted normal range. In 30 patients with proven carcinoma of the pancreas, a pancreatic mass was seen in 24 (83%). Computerized tomography is clearly a valuable method for viewing both normal pancreatic anatomy and anatomical variations and pathologies.
A new technique of computed tomography (CT) applied to the diagnosis of abdominal aortic aneurysms is described, and the experience in 58 patients is reviewed. In all instances the abdominal aorta was clearly demonstrated, even when wall calcification was absent. A series of 37 patients with abdominal aortic aneurysm underwent evaluation by physical examination, abdominal roentgenograms, and ultrasonic and CT scanning. Measurements of the transverse diameter at the point of maximal dilatation were compared with the measurements made at operation. CT not only confirmed the diagnosis in all patients but the measurements obtained by this technique were the most accurate, correlating extremely well with the true dimensions of the aneurysm. The addition of contrast enhancement to CT scanning allowed clear delineation of the aortic lumen and intraaneurysmal thrombus, not possible with any other method, including ultrasonography. The technique appears useful as a screening procedure and in the differential diagnosis of a tortuous abdominal aorta. Patients with a small aortic dilatation can be followed accurately by scanning.
Three patients with various pectus excavatum deformities in whom radiographic findings suggested hilar and mediastinal masses are presented. Computed tomography of the chest yielded valuable diagnostic information and made it possible to exclude the existence of these masses. Compression deformity of the heart and great vessels by the pectus deformity is the most likely explanation for these findings.