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Biomedical subjects

F Earnest

Publications and source records attributed to F Earnest.

At least 37 records · Page 2Linked to original sources
PubMed1985

Surgical options for patients with deep-seated brain tumors: computer-assisted stereotactic biopsy.

The histologic nature of deep-seated intracranial lesions can be determined by using a computer-assisted stereotactic biopsy technique. The procedures are performed with use of local anesthesia. A data base consisting of stereotactic computed tomographic scans and stereotactic cerebral angiography is acquired. Target coordinates and trajectory approach angles are calculated by using a computer system in the operating room. Since July 1984, 36 patients with a variety of pathologic lesions in various intracranial sites have undergone this procedure at our institution. Of the 36 patients thought to have neoplastic lesions preoperatively, 6 were found to have nonneoplastic lesions, information that was of importance in the therapeutic management of these patients. Of the 30 patients with tumors, 24 had astrocytomas of various grades, 3 had metastatic lesions, and an additional 3 had lymphomas. Computer-assisted stereotactic biopsy with arteriographic control is an accurate and relatively safe method of determining the histologic nature of any suspicious intracranial lesion.

Adenocarcinoma↗
PubMed1985

Magnetic resonance imaging for neurotoxicity in long-term survivors of carcinoma.

Neurotoxicity is a potential complication of combined chemotherapy and whole-brain radiotherapy in long-term survivors of carcinoma. Clinical features of this neurotoxicity are similar to those manifested in the leukoencephalopathy of pediatric patients with leukemia who have been treated prophylactically with whole-brain radiotherapy and chemotherapy. Magnetic resonance imaging, because of its ability to distinguish cortical gray matter and white matter and its utility for studying demyelinating diseases, was used in the assessment of five long-term survivors of carcinoma who had clinical evidence of neurotoxicity. On magnetic resonance examinations, all five patients had profound abnormalities in the periventricular white matter. These changes were considerably more pronounced than those seen on computed tomographic scanning. Thus, magnetic resonance imaging may serve as a useful procedure for early detection of neurotoxicity in patients with carcinoma who have received cerebral radiotherapy and chemotherapy.

Aged↗
PubMed1985

Present and future developments of stereotactic technology.

Incorporation of a surgical computer system into stereotactic methodology provides the facility for efficient utilization of the multiple data bases at the disposal of the modern stereotactician. Computed tomography, magnetic resonance imaging, and digital fluoroscopy data gathered in stereotactic conditions are digitized into a stereotactic surgical matrix for surgical planning and interactive surgical procedures. The advantages of this system are illustrated in stereotactic biopsy, interstitial irradiation, and laser resections of intracranial tumors.

Biopsy↗
PubMed1985

Magnetic resonance imaging vs. computed tomography: advantages and disadvantages.

Magnetic resonance imaging (MRI) of the head and spine exceeds the sensitivity of computed tomography (CT) in detecting parenchymal lesions of the brain and spinal cord. MRI should be employed as a screening examination, particularly in patients suspected of having demyelinating diseases. CT continues to be the imaging technique of choice in evaluation of trauma, accurately depicting bony abnormalities and intracranial hemorrhage in evaluation of the spinal column and suspected disc herniation and in uncooperative patients.

Astrocytoma↗
PubMed1984

Digital subtraction angiography.

Digital subtraction angiography is a new technique that combines fluoroscopic and computer technology to image the vascular system. This "angiogram" is fast and safe, can be performed on outpatients, and requires only intravenously administered contrast medium.

Angiography↗
PubMed1984

Complications of cerebral angiography: prospective assessment of risk.

A prospective study of 1,517 consecutive cerebral angiographic examinations is reported. The incidence of all complications was 8.5%, and the incidence of all neurologic complications was 2.6%. The overall incidence of permanent neurologic deficit was 0.33%. The incidence of permanent neurologic deficit in patients referred for evaluation of symptomatic cerebrovascular disease was 0.63%. Older age, increased serum creatinine concentration, and the use of more than one catheter all were significantly associated with serious neurologic complications. Although patients with a recent stroke or frequent transient ischemic attacks had a higher incidence of serious neurologic complications, this increase was not statistically significant for this sample.

Adolescent↗
PubMed1984

Spin-spin relaxation time (T2) dependence in MR saturation- and inversion- recovery images.

The intensities of regions of interest in saturation-recovery (SR) and inversion-recovery (IR) images obtained with a new magnetic resonance (MR) scanner were compared with theoretically expected results, using phantom materials that had been accurately characterized in a specialized MR spectrometer. The data revealed significant dependence on the spin-spin relaxation time (T2), which was not expected on the basis of a simple model. The cause of this T2 dependence is discussed. The appearance and contrast of certain tissues in IR and SR images may be different than expected on the basis of the simple model. The results indicate that caution is required in making general claims about the efficacy of specific MR techniques because of potential subtle differences in the way that even the most basic sequences are implemented on individual imaging devices.

Electron Spin Resonance Spectroscopy↗
PubMed1983

The accuracy and limitations of intravenous digital subtraction angiography in the evaluation of atherosclerotic cerebrovascular disease: angiographic and surgical correlation.

Intravenous digital subtraction angiography (IV-DSA) and subsequent conventional selective carotid angiographic examinations were reviewed in 78 patients who were suspected of having cerebrovascular disease, and the results were correlated with surgical findings in 53 patients. The impact of the information provided by each of these examinations on subsequent therapy was reviewed. IV-DSA examinations of acceptable quality accurately depict atherosclerotic lesions in the cervical carotid arteries. We found IV-DSA to be deficient for detection of intracranial vascular disease.

Angiography↗
PubMed1982

Computed tomography of orbital tumors, including late-generation scanning techniques.

The role of computed tomography (CT) in the detection and diagnosis of orbital tumors at the Mayo Clinic is reviewed. Special techniques of late-generation scanners, including multiplane reformatted imaging, off-axis projections, high-resolution retrospective analysis, and thin-section scanning, have been evaluated in various ways for their clinical application in 42 recent cases. The overall series involved 133 proved orbital tumors. The detection rate and information obtained established CT as the method of choice for diagnosis of tumors of the orbit.

Adolescent↗
PubMed1982

High-resolution dynamic ultrasound imaging of the carotid bifurcation: a prospective evaluation.

One hundren patients underwent high-resolution dynamic ultrasound imaging of the carotid bifurcation immediately before cerebral angiography. The examinations were interpreted independently. A positive ultrasound interpretation indicated the presence of moderate to extensive atheromatous plaque, while a negative interpretation indicated normal vessels or minimal atheromatous disease. Ten percent of the ultrasound examinations were technically unsatisfactory. Of the remaining studies, there was satisfactory correlation between ultrasound and angiography in approximately 85% and disagreement in 15%. The majority of ultrasound errors were "false positive" (although these probably represent false-negative angiograms). Although atheromatous disease was accurately detected by ultrasound, stenosis, ulceration, intraluminal thrombus, and vessel occlusion were not reliably identified.

Adolescent↗
PubMed1982

Digital angiography: introducing digital techniques to clinical cerebral angiography practice.

Digital subtraction angiography provides a computerized radiographic method of imaging the vascular system. These computer techniques may be used with arterial catheterization (digital arterial angiography) and with intravenous contrast injection (digital venous angiography). Both methods are changing the diagnostic evaluation and therapeutic follow-up of patients with cerebrovascular disease.

Brachiocephalic Trunk↗
PubMed1981

Fact or artifact: an analysis of artifact in high-resolution computed tomographic scanning of the sella.

Computed tomography (CT) artifacts within the sella turcica, associated with the bones of the skull base, were identified and examined by use of a human skull phantom immersed in water. These artifacts were identified in 63% of 27 clinical high-resolution CT scans performed on patients with suspected sellar or parasellar pathology. Intrasellar artifacts may be minimized or eliminated by careful choice of scanning plane. Identification and elimination of intrasellar CT artifacts are necessary for accurate interpretation of sellar image.

Adult↗
PubMed1979

Roentgenographic findings in thoracic aortic dissection.

Review of 91 confirmed cases of thoracic aortic dissection revealed that the findings on the plain films of the chest often were suggestive of the diagnosis, with abnormalities in the aortic countour, especially when comparison was made with previous roentgenograms. The diagnosis was definitively made in 52 cases by retrograde transfemoral or transaxillary catheterization accomplished without complication. The most common angiographic findings were opacification of the false lumen, visualization of an intimal flap, and deformity of the true lumen. Early diagnosis and institution of appropriate therapy can improve survival in this disease.

Adult↗