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D R Enzmann

Publications and source records attributed to D R Enzmann.

At least 109 records · Page 6Linked to original sources
PubMed1982

Short term, high dose corticosteroids in computed tomographic staging of experimental brain abscess.

A short term, high dose corticosteroid treatment protocol was investigated to determine its clinical utility in staging an experimental brain abscess. Corticosteroids were shown to decrease the degree of contrast enhancement of brain abscess 12 h after administration but the magnitude of the effect was not consistent enough to be clinically useful in staging. The corticosteroid effect progressively diminished as the inflammatory lesion encapsulated over time. This effect emphasized that a decreasing ring diameter and not diminished contrast enhancement should be the CT criterion for brain abscess resolution.

Adrenal Cortex Hormones↗
PubMed1982

CT of irradiated solid tumor metastases to the brain.

Twenty patients with solid tumor metastases to the brain, demonstrated by CT scanning, had follow-up scans after radiation therapy of the metastatic focus. Nine patients (45%) showed no evidence of the metastasis on the initial follow-up scans. Another 10 patients (50%) showed some improvement in the size, enhancement, or surrounding edema of the lesion. Only one patient showed progression in spite of therapy. The CT scan identified those patients who achieved longer survival and/or longer time intervals before brain relapse. However, CT scans must be interpreted with caution in patients still on corticosteroid treatment. Additionally, other non-tumoral conditions may mimic tumor recurrence. Radiation therapy offered palliation in patients with brain metastases, and in some instances, sterilized patients of their metastatic brain involvement.

Adult↗
PubMed1982

High-resolution ultrasound evaluation of experimental brain abscess evolution: comparison with computed tomography and neuropathology.

Computed tomographic (CT) and high-resolution ultrasound (HRUS) imaging of experimental brain abscess were correlated with neuropathologic findings in nine mongrel dogs. The HRUS scan was more sensitive to different histologic features than the CT scan but both accurately delineated the evolution of the experimental brain abscess. All stages of abscess evolution were characterized by an appearance of an echogenic rim with a hypoechoic center. In the early stages the echogenicity of the abscess was related primarily to marked cellular infiltration, while in the late stages extensive collagen deposition correlated closely with the echo pattern. The size of the abscess in the cerebritis stages appeared smaller on the HRUS scan than on the CT scan because the latter modality detected the extensive cerebritis around the developing necrotic center whereas the HRUS scan did not. This discrepancy disappeared in the capsule stages. The HRUS scan provided a more accurate depiction of the neuropathologic characteristics of the necrotic than did the CT scan. Healing of the abscess, indicated by a decrease in size of the hypoechoic center, was accurately detected by the HRUS scan.

Animals↗
PubMed1982

The effect of short-term corticosteroid treatment on the CT appearance of experimental brain abscesses.

The effect of short-term corticosteroid treatment on contrast enhancement was investigated in an experimental brain abscess model. The degree of enhancement was reduced in the cerebritis stage, unaffected in the capsule stage, and intermediate in the transitional stage. The area and pattern of enhancement were also altered in the cerebritis stage. Although the magnitude of the entire cerebritis time-density curve (extended for 60 minutes) was decreased by the steroids, its configuration was unchanged. Prior to steroid administration, the 10- and 60-minute components of the curve discriminated between cerebritis and capsule stages, with the latter exhibiting a far lower 60-minute value. Implications for treatment of brain abscesses are discussed.

Animals↗
PubMed1981

Intracranial infection in cardiac transplant recipients.

Infections have produced most of the deaths in the Stanford cardiac transplant program. Of the first 182 transplant recipients, 27 developed nonviral intracranial infections: meningoencephalitis/abscess in 16 patients, meningitis in 9, and rhinocerebral phycomycoses in 2. The responsible organisms included aspergillus, toxoplasma, candida, klebsiella, cryptococcus, coccidioides, listeria, mucor, and rhizopus. Characteristically, the areas of meningoencephalitis and abscesses were multiple and deep seated. Intracranial infections were invariably associated with pulmonary or disseminated infection with same organism. Computed tomographic (CT) brain scans in patients with meningoencephalitis often showed minimal, nonspecific, low-density lesions which usually did not exhibit contrast enhancement. At surgery the lesions were found to differ from typical pyogenic abscesses in that capsules were not well developed, and the aspirate consisted of necrotic fragments of edematous white matter and inflammatory cells rather than liquefied pus. Aspergillus infections of the central nervous system usually developed within the first three months after transplantation. Cases of meningitis occurred at variable times after transplantation, but approximately half appeared within 30 days after immunosuppressive therapy for treatment of rejection was increased. The prognosis for brain abscess depended on the causative organism. All patients with aspergillus infection died despite treatment with amphotericin B. The toxoplasma abscess responded to a combination of sulfadiazine and pyrimethamine. Meningitis was successfully suppressed or cured with appropriate treatment except for 1 patient with disseminated cryptococcosis.

Adult↗
PubMed1981

Planned approach to the management of malignant invasion of the carotid artery.

A planned approach to the evaluation and management of patients with tumor involvement of the cervical carotid artery is presented. Preoperative arteriography and determination of carotid back-pressure permitted a rational approach in these high risk patients. One patient found to have an extremely low carotid back-pressure was advised not to undergo carotid resection. Six patients with satisfactory carotid back-pressure tolerated carotid resection and reconstruction.

Blood Pressure↗
PubMed1981

Compromised CT detection of extracranial malignant neoplasms by steroid treatment.

Computed tomographic attenuation coefficients in six rabbit thigh V2 carcinomas were studied before and after steroid treatment. In four V2 tumors with effective steroid treatment, the density difference between V2 carcinoma and normal muscles decreased on both pre- and postcontrast scans (17.9 and 21.8 Hounsfield units, respectively--HU: 1,000 scale) attributable mainly to altered tumor X-ray absorption; 3 weeks after steroid withdrawal, normal and malignant tissue density differences increased and returned toward base line. Two V2 tumors failed to respond to steroids; the precontrast density difference between V2 carcinoma and normal muscle was nearly constant, and the postcontrast density difference increased by 6.8 HU. In patients taking steroids, malignant tumors may become isodense with the surrounding normal tissue and be difficult or impossible to detect. Changes in tumor density may also prove to be a useful marker off therapeutic efficacy.

Absorptiometry, Photon↗
PubMed1981

The evolution of white matter disease as seen on computed tomography.

The evolving computed tomographic (CT) findings in three patients with different types of dysmyelinating white matter diseases (Krabbe, Canavan, ketotic hyperglycinemia) are presented. Serial CT scans suggested that the abnormal, low density white matter, which is characteristic of many white matter diseases, is present for only a limited time, corresponding to active dys- or demyelination. The low density abnormality gives way to a nonspecific final common pathway manifested as severe atrophy on CT. Ventricular enlargement is accentuated in this form of atrophy which appears to be the final stage in a wide variety, if not all, of white matter diseases.

Atrophy↗
PubMed1981

Using computed tomography of the brain to correlate low white-matter attenuation with early gestational age in neonates.

Computed tomographic brain scans of the newborn exhibit relatively greater lucency of white matter compared to the mature patient. This study correlated the x-ray attenuation of white matter with gestational age in 23 neonates, both premature and term. The gray-white matter attenuation difference was calculated and plotted versus advancing gestational age. An inverse correlation was found between the gray-white matter density difference and advancing gestational age. Statistical analysis revealed that this phenomenon is due to increasing white matter density in the first months of life with the gray matter showing no significant variation with advancing age. The low attenuation value of white matter in the perinatal period and its subsequent increase is a normal phenomenon; it correlates with the greater water and lower protein content of premyelinated white matter initially, followed by subsequent water loss and protein gain with myelination. Since transient cerebral edema due to hypoxia exhibits similar low attenuation with CT, it is difficult to exclude this entity in the premature infant group where accurate neurologic evaluation is hard to obtain.

Brain↗
PubMed1981

Intravenous carotid arteriography using line-scanned digital radiography.

Digital subtraction and an experimental system for line-scanned radiography were used to image the bifurcations of the carotid arteries. The subtracted images were obtained before and after injections of contrast media. The anatomy of the extracranial carotid arteries was demonstrated in most patients, and verified by selective catheter arteriograms. Unsuccessful studies were attributed to improper timing while obtaining the images, and to venous occlusion. Artifacts produced by motion limit the temporal subtraction method.

Angiography↗
PubMed1981

Prolonged brain retention of contrast agent in neonatal herpes simplex encephalitis.

A neonate with herpes simplex encephalitis type 2 manifested progressively increasing density of the gray matter on serial computed tomographic scans. Postmortem examination of the brain proved the cause of the increased density to be a high concentration of iodine that had been retained following the intravenous administration of sodium diatrizoate 25 and 16 days previously. This demonstrates that a water-soluble iodinated contrast agent or its iodine component may be retained in the brain for a prolonged period of time. It is recommended that such agents be avoided when possible in neonates with herpes simplex encephalitis.

Brain↗
PubMed1981

Occult arteriovenous malformation of the brainstem simulating multiple sclerosis.

A patient who proved to have an angiographically occult arteriovenous malformation of the brainstem and cerebellum was thought to have multiple sclerosis for 20 years, because of fluctuating brainstem symptoms and signs. Although the computed tomographic (CT) appearance of the lesion suggested a vascular malformation, because it bridged the subarachnoid space between the brainstem and cerebellum, an arteriogram was normal. This report stresses the importance of CT in making the diagnosos of occult arteriovenous malformations of the brainstem. On CT scan, these lesions generally have a high-density multiform appearance, which may enhance with contrast infusion. This lesion should be suspected clinically when there are fluctuating neurologic symptoms and signs attributable to the same neuroanatomic location within the brainstem. Surgical biopsy may confirm the diagnosis, but attempts to remove these lesions from the brainstem parenchyma are hazardous and probably are not indicated, considering the chronic and relatively benign course.

Adolescent↗
PubMed1981

Perfluoroctylbromide contrast enhancement of malignant neoplasms: preliminary observations.

Fluorocarbons have been used for years as propellants in aerosol sprays. Because of their ability to transport oxygen, perfluorocarbon compounds have been more recently used in artificial fluid respiration. Monobrominated perfluorocarbon compounds are radiopaque and have low enough vapor pressures to be tolerated in biologic systems. Microemulsions of these compounds have been detected in mouse and rat neoplasms and appear to be located within macrophages. In this study of the potential usefulness of these compounds for radiographic contrast enhancement, rabbits with V2 carcinoma thigh implants received either a high-dose (10--12 ml/kg) or a low-dose (2 ml/kg) emulsion of perfluoroctylbromide intravenously. Dense contrast enhancement of some of the V2 carcinomas was demonstrated by both computed tomography and conventional radiography. Four of the five rabbits in the high-dose group died within 9 days but all six rabbits in the low-dose group survived beyond 9 days. Death in the high-dose group was associated with pulmonary consolidation and anesthesia although some animals had extensive V2 metastases. These compounds have some interesting potential applications in imaging, pending further study of their toxicity.

Animals↗
PubMed1981

Experimental study of high-resolution ultrasound imaging of hemorrhage, bone fragments, and foreign bodies in head trauma.

The accuracy of high-resolution ultrasound scans in detecting foreign bodies and hemorrhage within the brain was evaluated by comparison with computerized tomography (CT) scans and gross pathology. The test lesions were blood and foreign bodies consisting of bone, wood, and metal placed in the brain of an experimental animal. High-resolution ultrasound scans (10 MHz) performed in coronal and sagittal planes accurately delineated the position and spatial orientation of these foreign bodies and hemorrhage. Both hemorrhage and foreign bodies were echogenic compared to normal, hypoechoic brain parenchyma. Metal fragments had a highly characteristic echo pattern caused by sound reverberation within the object. Acute intracerebral hemorrhage produced an ultrasound image consisting of sharply circumscribed homogeneous echoes. The sonographic shape of intracerebral hemorrhage correlated closely with the area of increased density seen on the CT scan. High-resolution ultrasonography accurately delineated experimentally produced components of head trauma and may prove useful as an intraoperative imaging technique to facilitate surgery in head-injured patients.

Animals↗
PubMed1981

Neuropathological and computerized tomographic findings in experimental brain abscess.

The neuropathological progression of brain abscess formation was studied experimentally at sequential stages in dogs, and the findings correlated with the appearance on computerized tomographic (CT) brain scans. The evolution of brain-abscess formation was divided into four stages based on histological criteria: early cerebritis (Days 1 to 3); late cerebritis (Days 4 to 9); early capsule (Days 10 to 13); and late capsule (Days 14 and later). The cerebritis stage was characterized by prominent perivascular cuffing by inflammatory cells in the area adjacent to the developing necrotic center. However, the early elements of capsule formation appeared with the presence of fibroblasts by Day 5. The CT scans showed ring-shaped contrast enhancement by Day 3. Delayed scans at 30 minutes revealed diffusion of the contrast material into the developing necrotic center, forming a solid lesion. In lesions that were well encapsulated (14 days and older), five distinct histological zones were apparent: 1) a well formed necrotic center; 2) a peripheral zone of inflammatory cells, macrophages, and fibroblasts; 3) the dense collagenous capsule; 4) a layer of neovascularity associated with continuing cerebritis; and 5) reactive astrocytes, gliosis, and cerebral edema external to the capsule. The CT appearance of well encapsulated abscesses showed a typical ring-shaped contrast-enhancing lesion. On the delayed scans, the "ring" did not fill in with contrast enhancement. The diameter of the ring correlated best with the presence of cerebritis (perivascular infiltrates in the adventitial sheaths of vessels surrounding the abscess). The discussion focuses on the relevance of this study to the current management of patients with brain abscess.

Animals↗
PubMed1980

Carotid back pressures in conjunction with cerebral angiography.

A method for obtaining carotid back pressures at the time of cerebral angiography is described. These preoperative measurements were compared to intraoperative measurements in 18 patients. Preoperative mean carotid back pressures (usually common carotid pressures) were obtained by occluding the artery with a double-lumen balloon catheter and recording the pressure distal to the balloon. Although the mean arterial blood pressure and the arterial carbon dioxide tension proved to be variables, the correlation of the pressures measured at angiography and at surgery was high (p less than 0.001).

Arteriosclerosis↗