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Biomedical subjects

E G Grant

Publications and source records attributed to E G Grant.

At least 19 recordsLinked to original sources
PubMed1999

Effect of US contrast agents on spectral velocities: in vitro evaluation.

PURPOSE: To evaluate the effect of ultrasonographic (US) contrast agents on measurements of peak velocity with spectral Doppler US in stenotic and nonstenotic flow states. MATERIALS AND METHODS: Nonpulsatile flow was established in a flow phantom with 0%, 50%, 75%, and 90% stenoses. SH U 508A, perflenapent emulsion, and perfluorohexane emulsion were the contrast agents evaluated. Before and after administration of each contrast agent, two peak velocity measurements obtained proximal to, at the site of, and distal to the stenosis in each vessel model were averaged. The percentage difference in peak velocity after contrast agent administration was calculated for each site interrogated. The mean, SD, and coefficient of variation of the percentage difference in peak velocity were calculated. RESULTS: Percentage differences in peak velocity after contrast agent administration at different sample volume sites were not significantly different irrespective of the degree of stenosis or the contrast agent evaluated. CONCLUSION: The contrast agents evaluated do not produce a statistically significant increase in peak velocity. If this result is corroborated in clinical practice, contrast agents can be used without reevaluating existing Doppler US thresholds for stenosis.

Constriction, Pathologic↗
PubMed1999

Transvaginal saline hysterosonography: characteristics distinguishing malignant and various benign conditions.

OBJECTIVE: The objective of this study is to establish criteria for distinguishing endometrial polyps, submucosal leiomyomas, endometrial hyperplasia, and endometrial carcinoma on saline hysterosonography. MATERIALS AND METHODS: Sixty-three saline hysterosonograms with histologic confirmation were retrospectively analyzed. We found 26 endometrial polyps, 16 submucosal leiomyomas, three endometrial hyperplasias, one abnormal endometrium associated with a sloughed polyp, one pseudopolyp, and three endometrial carcinomas; 15 sonograms revealed no abnormality. In two patients, sonography revealed both polyps and submucosal leiomyomas. The sonographic appearance of these abnormalities was analyzed to define criteria for their diagnosis. RESULTS: Twenty-five of 26 polyps were uniformly echogenic with smooth borders and either had a stalk or formed acute angles with underlying endometrium. Sixteen of 16 submucosal leiomyomas showed heterogeneous echogenicity; however, 13 were sessile and three were pedunculated. Endometrial hyperplasia was manifested by wall thickening in two patients and tiny polypoid excrescences in one patient. In all patients with endometrial carcinoma, the endometrial cavities were poorly distensible despite successful cervical os cannulation. All patients with abnormalities other than endometrial carcinoma had fully distensible uterine cavities. CONCLUSION: Malignant and various benign endometrial conditions may be accurately distinguished on saline hysterosonography. Uniformity of echogenicity distinguished all polyps from submucosal leiomyomas, but the angulation formed with the endometrial wall by the intracavitary mass did not distinguish all polyps from submucosal leiomyomas. Lack of distensibility of the endometrial canal is a potential sign of endometrial carcinoma.

Adult↗
PubMed1998

Planning and cost analysis of digital radiography services for a network of hospitals (the Veterans Integrated Service Network).

This study analysed the design and cost of a picture archiving and communications system (PACS), computerized radiography (CR) and a wide-area network for teleradiology. The Desert Pacific Healthcare Network comprises 10 facilities, including four tertiary medical centres and one small hospital. Data were collected on radiologists' workloads, and patient and image flow within and between these medical centres. These were used to estimate the size and cash flows associated with a system-wide implementation of PACS, CR and teleradiology services. A cost analysis model was used to estimate the potential cost savings in a filmless radiology environment. ATM technology was selected as the communications medium between the medical centres. A strategic plan and business plan were successfully developed. The cost model predicted the cost-effectiveness of the proposed PACS/CR configuration within four to six years, if the base costs were kept low. The experience gained in design and cost analysis of a PACS/teleradiology network will serve as a model for similar projects.

California↗
PubMed1998

Significance of fetal intracardiac echogenic foci in relation to trisomy 21: a prospective sonographic study of high-risk pregnant women.

OBJECTIVE: The aim of the study was to determine if an association exists between intracardiac echogenic foci in the second-trimester fetus and trisomy 21. SUBJECTS AND METHODS: Over a 2-year period, targeted fetal sonography was performed for various indications in 1593 second-trimester high-risk pregnant women. Presence or absence of echogenic foci was recorded for each fetus. Amniocentesis for karyotype analysis was performed in 901 subjects immediately after sonography. The findings of these 901 subjects formed the basis of this report. RESULTS: Intracardiac echogenic foci were present in the left ventricle of 24 (3%) of the 901 fetuses. Three (13%) of these 24 fetuses had trisomy 21; no chromosomal abnormalities were found in the other 21 fetuses. Karyotype analysis revealed trisomy 21 in 14 (2%) of the remaining 877 fetuses who did not exhibit intracardiac echogenic foci. The sensitivity, specificity, positive predictive values, and negative predictive values for intracardiac echogenic foci in predicting trisomy 21 were 18%, 98%, 13%, and 98%, respectively. The association of intracardiac echogenic foci and trisomy 21 was significant (p < .009) by the two-tailed Fisher's exact test. CONCLUSION: In a high-risk obstetric population, the association between fetal intracardiac echogenic foci and trisomy 21 was statistically significant. Therefore, women carrying fetuses with intracardiac echogenic foci should be informed of the statistical association with trisomy 21.

Adolescent↗
PubMed1998

Disclosure of results of sonographic examinations to patients by sonologists.

OBJECTIVE: The aim of this study was to assess if patients prefer to talk with a sonologist concerning the results of sonographic examinations. MATERIALS AND METHODS: The study involved outpatients who underwent diagnostic sonography. Technologists offered patients the chance to speak with a sonologist about the results of their sonograms. If requested, a sonologist reviewed the results, and if the study showed an abnormality, its significance was discussed. No treatment recommendations were offered. Patients then filled out a questionnaire. RESULTS: Of the 391 outpatients given the choice, 348 (89%) requested a consultation and 207 of those (60%) returned the completed questionnaire. Of the 207 patients completing the questionnaire, 94% preferred receiving the results from the sonologist rather than from their referring physician. CONCLUSION: We propose a revision of the traditional role of the office-based sonologist to one in which he or she will function as a consultant to both the patient and the patient's physician.

Outpatients↗
PubMed1997

Clinical experience with sonographic contrast agents.

Early generations of sonographic contrast agents are beginning to reach the attention of the clinician. Research and development of ultrasound contrast agents is progressing at a rapid pace with several new agents approaching US Food and Drug Administration approval. Cardiac imaging has been affected by even the limited availability of contrast agents on the market today both with regard to diagnosis of shunts and chamber opacification, and most recently actual enhancement of the myocardium. Later generations of contrast are capable of providing consistent opacification of both peripheral veins and arteries, and should prove useful in a variety clinical applications. Thus far, it appears that longer vessel segments may be seen with contrast rather than without contrast, and that flow may be demonstrated in vessels which were not seen or thought to be occluded with conventional color imaging. Improved detection of arterial and venous collaterals and enhanced identification of run-off vessels is demonstrated with sonographic contrast agents. An improved ability to evaluate renal artery stenosis and subtotal occlusion of the carotid artery are specific advantages of using contrast as well. Several compounds are currently being tested that may allow routine parenchymal opacification. Ultrasound is the most commonly performed diagnostic imaging procedure; therefore, contrast agents have the potential to dramatically alter the practice of clinical medicine. This article reviews the current status of ultrasound contrast agents and speculates regarding the future applications of these agents.

Albumins↗
PubMed1997

Ability of a phase shift US contrast agent to improve imaging of the main renal arteries.

PURPOSE: To evaluate the ability of a phase shift contrast agent to improve Doppler sonographic imaging of the main renal arteries in cases of suspected renal artery stenosis. MATERIALS AND METHODS: In 25 patients in whom renal artery stenosis was suspected, baseline Doppler sonography was performed followed by two studies performed after blinded administration of contrast material or placebo (saline). Each kidney (n = 45) was evaluated for (a) visualization of the main renal artery on a scale of 0-4, (b) presence of accessory renal arteries, and (c) direct Doppler sonographic findings suggestive of renal artery stenosis. Correlative magnetic resonance angiography was performed in 24 patients, and angiograms were obtained in eight kidneys with stenosis at one or both imaging studies. RESULTS: Contrast enhancement was observed in 23 patients. Enhancement was 8-20 minutes. Renal artery visualization scores improved from a mean of 2.56 and 2.71 on baseline and noncontrast scans, respectively, to 3.69 after administration of contrast material. Contrast-enhanced images depicted seven kidneys with accessory renal arteries not seen at other studies. Two of eight cases of stenosis were seen only with contrast-enhanced sonography. CONCLUSION: Use of the phase shift contrast agent appears to enable a reduction in the number of equivocal findings of renal artery stenosis.

Adult↗
PubMed1997

Transcranial color Doppler imaging of brain arteriovenous malformations in adults.

This study was performed to investigate the utility of transcranial color Doppler sonography in evaluating adult cerebral arteriovenous malformations. Twelve patients with such malformations underwent sonography. Spectral Doppler sonographic assessment included peak systolic velocity, end diastolic velocity, and resistive index within the intracranial and extracranial vessels. Color Doppler sonography was used to visualize the site of shunting. Paired and unpaired Student's t-tests were used to determine significance of spectral findings. The nidus was seen in eight of 10 pial malformations. The nidi in two patients were located in the parietal region and not visualized. When compared with the corresponding contralateral artery, feeding arteries (identified in all 10 of the pial lesions) demonstrated diminished resistive indices (P = 0.09). Similarly, the end diastolic velocity was increased in all feeding arteries (P = 0.03). When compared with published normal values, the peak systolic and end diastolic velocities were significantly elevated and the resistive indices were low (P < 0.0003). Transcranial color Doppler sonography depicted the nidi of pial arteriovenous malformations in 80% of cases. Feeding arteries demonstrated abnormal peak systolic velocity, end diastolic velocity, and resistive index in all cases when compared with published values. Transcranial color Doppler sonography is not a good screening tool due to limited acoustical window, but it may be useful for noninvasive study of the physiology of arteriovenous malformations as they are treated.

Adult↗
PubMed1996

Ultrafast networks (ATM): first clinical experiences.

Ultrafast networks using asynchronous transfer mode (ATM) technology can provide the bandwidth and throughput that may be sufficient to satisfy the medical imaging community. Several trials are underway to assess the effect of ATM network capabilities on the clinical practice of radiology, by providing immediate interactive radiology consultations between subspecialists and general radiologists at affiliated academic institutions. The hardware to build such networks is now commercially available and its cost is decreasing steadily, but the monthly charges for ATM bandwidth use are still high. Nevertheless, given the tremendous increase in communication capability and data transfer rates possible with ATM networks, cost alone should not be the determining factor for selecting this technology. The ATM concept in general is first reviewed, followed by a description of early clinical ATM network installation in four medical environments worldwide. These medical clusters include: the UCLA affiliated hospitals (UCLA Medical Center, West LA VAMC and Olive-View UCLA Medical Center), the UCSF affiliated hospitals, Duke University Hospitals and a cluster of medical centers in Berlin which have all been connected via ATM networks. The use of ATM technology in these realistic clinical environments is discussed and evaluated for its potential impact on patient care and clinical teaching within radiology departments. From this preliminary study it is concluded that image communications over a regional PACS using an ATM network can allow interactive consultations between different subspecialist and general radiologists or other specialized radiologists spread over different medical centers.

Computer Systems↗
PubMed1996

Nurse evaluation of a pain medication protocol in a selective postoperative population.

Postoperative pain in 33 patients who underwent radical prostatectomy was managed by an intramuscular nonsteroidal antiinflammatory drug protocol rather than by administration of narcotics. Patients rated their perception of pain with a visual analog scale on the first postoperative day both before and after receiving ketorolac tromethamine. The medication was effective in relieving pain after this major operation. Costs were approximately one half that of the traditional narcotic protocol used before this study.

Adult↗
PubMed1994

Diverticular disease. Surgical options, patient management.

Diverticular disease is a common and occasionally complicated disease in our western society. Although the exact etiology is unknown, diet is thought to be a contributing factor to the formation of diverticula. Diverticular disease most often is managed medically. When surgery is indicated, perioperative nursing care is based on knowledge of the disease process and attention to the physical and emotional needs of the patient.

Diverticulitis, Colonic↗
PubMed1993

Teleconferencing for cost-effective sharing of radiology educational resources: potential and technical development.

To develop a cost-effective method of sharing educational resources, a dial-up teleconferencing network was implemented between three radiologic sites for a 30-day period of evaluation. By means of standard dial-up telephone channels, compressed video and audio signals displayed radiologic images, slides, and text, allowing residents and faculty from the three sites to participate in sight and sound interactions. Each of the three sites used compressed video/audio coder-decoders (codecs) conforming to the Consultative Committee on International Telegraphy and Telephony H.261 standard. Four video cameras were used at each site, and the audio was run in full duplex mode. A multipoint video bridge was used to broadcast codec output signals to the input lines of the other codecs. Our evaluation found audio quality to be suboptimal, but capable of being improved; diagnostic image quality was adequate when a video zoom mode was used; the digital-archive mode of the codec proved advantageous; the H.261 codec permitted participation from all sites; and all conference lecturers were able to conduct their conferences as they were accustomed. Although audio quality and spatial resolution need to be improved, the results of this pilot study imply that dial-up compressed video conferencing has the potential to become a practical, cost-effective method of sharing educational resources by means of interactive radiologic multisite educational programs.

Computer Communication Networks↗
PubMed1993

Color Doppler imaging findings in patients with Budd-Chiari syndrome: correlation with venographic findings.

OBJECTIVE: This study was undertaken to evaluate color Doppler imaging findings in patients with Budd-Chiari syndrome and to compare these findings with results of venography. SUBJECTS AND METHODS: In a prospective study, 21 patients with proved Budd-Chiari syndrome had color Doppler imaging. Sonographic evaluations ware performed to detect appropriately directed flow in the hepatic veins, portal vein, and inferior vena cava. Intrahepatic collaterals were characterized when present. Results of color Doppler imaging were compared with those of angiography in 20 patients. Color Doppler images of the hepatic veins were also obtained in a reference group (20 control subjects, 20 patients with hepatomegaly, and 20 patients with cirrhosis). RESULTS: Color Doppler imaging showed abnormalities of anatomy or flow in one or more of the main hepatic veins in all 21 patients with Budd-Chiari syndrome. Commonly observed abnormalities were visualization of a hepatic vein on real-time sonograms that had no flow or retrograde flow on color Doppler sonograms (11 cases) and no visualization of part or all of a hepatic vein on either real-time or color Doppler sonograms (10 cases). When compared with venographic findings (16 patients), findings on color Doppler sonograms could be used to distinguish patent from occluded hepatic veins in all cases. In our reference group, real-time and color Doppler sonograms showed normal hepatic veins in all control subjects. Real-time sonograms clearly showed hepatic veins in 12 of 20 patients with hepatomegaly; color Doppler sonograms showed flow in the hepatic veins in all 20 of these patients. Among 20 patients with cirrhosis, real-time sonograms showed hepatic veins in only seven; color Doppler imaging confirmed patent veins in 17. Intrahepatic collaterals typical of Budd-Chiari syndrome were observed in 10 of 21 patients with the syndrome. The portal vein was assessed by using color Doppler imaging in all 21 patients with Budd-Chiari syndrome; portograms were available for comparison in 10 patients. Findings were consistent in eight; in two cases, the direction of flow was reversed on color Doppler sonograms compared with portograms. For the inferior vena cava, venographic and sonographic findings correlated in 16 of 20 cases. Color Doppler sonograms did not show a caval web in one patient. CONCLUSION: Abnormalities of the hepatic veins, portal veins, and inferior vena cava detected on color Doppler sonograms in patients with Budd-Chiari syndrome correlate well with findings on venograms.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1993

Transcervical sonography: an investigational technique for visualization of the embryo.

A catheter-based, miniature ultrasound transducer, operating at a frequency of 12.5 MHz, was introduced transcervically into the uterine cavity of 18 pregnant women about to undergo first-trimester abortion. Transcervical sonography showed the yolk sac and embryonic structures, such as brain vesicles, limb buds, liver, spinal canal, and umbilical cord with blood flow, in eight embryos at 5-8 menstrual weeks of age. As an investigational technique, catheter-assisted transcervical sonography offers a new diagnostic approach to imaging of the first-trimester human embryo.

Abortion, Induced↗