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Biomedical subjects

J C Dillon

Publications and source records attributed to J C Dillon.

At least 73 records · Page 4Linked to original sources
PubMed1979

Inexpensive radiation protective glasses.

Using the services of a local optical supply house, fabrication and testing of eyeglasses of a high lead content that could be used to protect the eye from the hazards of radiation were evaluated. Two separate types of eyeglasses were manufactured (a prototype followed by a second pair), and these were tested against a commercially available pair of radiation protective glasses. The protection offered by the locally manufactured pair of glasses exceeded the commercial pair and the cost savings are significant.

Eye Protective Devices↗
PubMed1979

Serial echocardiographic appearance of healing bacterial vegetations.

Serial M mode and cross-sectional echocardiograms were obtained from six patients who had been treated with antibiotic drugs for infectious endocarditis. Three to six M mode echocardiograms and one to six cross-sectional echocardiograms were obtained from each patient over a follow-up period averaging 50 weeks (range 10 to 108 weeks). On echocardiography, vegetations were observed to have become smaller and more echo-reflective with healing. A dramatic change was seen in two patients after peripheral embolization. M mode echocardiography was particularly helpful in determining the quality of echo reflection by vegetations; cross-sectional echocardiography was more helpful in judging the size and shape of a vegetation. Echocardiography is ideally suited for the serial visualization of healing vegetations in patients who do not require early valve replacement. It may prove helpful to examine serially valve vegetations with both M mode and cross-sectional echocardiography when following up patients with infectious endocarditis treated with antibiotic agents.

Adult↗
PubMed1979

Long-term changes in mitral valve area after successful mitral commissurotomy.

We examined the long-term effects of closed instrumental mitral commissurotomy on mitral valve area (MVA) in 18 patients, followed for as long as 14 years after successful operation. Each patient had preoperative and early postoperative cardiac catheterization; late postoperative determination of MVA was obtained 10-14 years (mean 12.2 years) after commissurotomy. In 17 patients, the MVA was determined by cross-sectional echocardiography and in one patient by repeat cardiac catheterization. Thirteen of 18 patients had no change in MVA between early postoperative study (mean MVA = 2.7 cm2) and late postoperative study (mean MVA = 2.9 CM2). MVA in five patients decreased 0.7-2.2 cm2 (mean 1.4 cm2) during the follow-up period. In these five patients, the mean MVA at early postoperative study was 2.7 cm2 and at late postoperative study was 1.3 cm2 (p less than 0.001). At late postoperative evaluation, cardiac symptoms were associated with severity of mitral stenosis but did not predict restenosis. A successful, closed, instrumental mitral commisurotomy can provide substantial long-term improvement in MVA.

Cardiac Catheterization↗
PubMed1979

Comparison of M-mode and cross-sectional echocardiography in infective endocarditis.

Cross-sectional and M-mode echocardiograms were performed on 23 consecutive patients with infective endocarditis. Both M-mode and cross-sectional echocardiography identified vegetations in 18 patients, 10 of whom required valve replacement within 1 month of presentation. Cross-sectional echocardiography alone identified a vegetation in one patient with a prosthetic valve. Neither technique identified vegetations in five instances. The size and shape of a vegetation on cross-sectional echocardiography did not accurately predict the need for early valve replacement of the incidence of major peripheral emboli.

Adult↗
PubMed1979

Exercise cross-sectional echocardiography in ischemic heart disease.

We performed cross-sectional echocardiograms at rest, during supine bicycle exercise, and after sublingual nitroglycerin administration in 28 patients suspected of having ischemic heart disease. Technically adequate exercise cross-sectional echocardiograms were obtained in 20 patients (71%). Ten patients had new areas of reversible segmental dysynergy, and all 10 had significant stenoses of coronary arteries supplying areas of the heart corresponding to the location of reversible dysynergy. Six of these 10 patients also underwent exercise thallium-201 perfusion scanning, and all six had reversible perfusion defects in the area that demonstrated reversible dysynergy on exercise cross-sectional echocardiography. At least two of the remaining 10 patients who did not have reversible segmental dysynergy on exercise cross-sectional echocardiography probably experienced myocardial ischemia that we did not detect. We conclude that exercise cross-sectional echocardiography is technically difficult but feasible. The mechanical consequences of exercise-induced regional myocardial ischemia can be detected noninvasively by real-time, two-dimensional, cross-sectional echocardiography.

Adult↗
PubMed1978

Cross-sectional echocardiographic characterization of aortic obstruction. 1. Supravalvular aortic stenosis and aortic hypoplasia.

Cross-sectional echocardiographic and cineangiographic studies of the left ventricular outflow tract and ascending aorta were performed in five patients with supravalvular aortic stenosis (four hourglass and one hypoplastic). Visualization of the area of obstruction was possible in each patient using the cross-sectional system. In each case the echocardiographically determined diameter at the level of obstruction was within 3 mm of the similar angiographic value. Assessment of the extent of the lesion was possible in four of five cases. In three of these four cases the echocardiographic measurement was within 5 mm of the angiographic measurement while in the fourth the obstruction was felt to involve the total ascending aorta by both techniques. Determination of percent decrease in LVOT diameter from the aortic anulus to the level of obstruction was useful in defining obstruction and estimating severity. Cross-sectional echocardiography is a valuable noninvasive method for evaluating the ascending aorta in patients with supravalvular aortic stenosis.

Adolescent↗
PubMed1978

Cross-sectional echocardiographic detection of aortic obstruction. 2. Coarctation of the Aorta.

Cross-sectional echocardiographic studies of the aortic arch and proximal descending aorta were performed in 18 patients with coarctation of the aorta and 20 normal subjects. In normals the aortic arch and proximal descending aorta appeared as an arcuate, echo-free structure curving across the plane of the scan. There were no localized changes in aortic diameter and the amplitude of aortic systolic pulsation was symmetrically maintained throughout the scan plane. Visualization of this region was possible in 16 of 18 patients with coarctation. In each of these cases there was a localized area of decrease in aortic diameter in the region of the left subclavian artery which corresponded to the angiographic appearance of the coarctation. In addition prominent systolic pulsation of the aortic arch proximal to the region of obstruction was evident. Cross-sectional echocardiography may offer a useful noninvasive method for direct visualization of aortic coarctation.

Adolescent↗
PubMed1978

Determination of mitral valve area by cross-sectional echocardiography.

Cross-sectional echocardiograms of the mitral valve orifice were recorded in 37 patients with mitral stenosis. Twenty-seven had pure mitral stenosis, and 10 had associated mitral regurgitation. Mitral valve area in patients with pure mitral stenosis measured from cross-sectional echocardiography was highly correlated (r = 0.89) with that calculated with the Gorlin formula using the pressure gradient and Fick cardiac output. With mitral regurgitation, mitral valve area by cross-sectional echocardiography correlated well (r = 0.90) with that calculated from the pressure gradient and cineangiographic stroke output. In two cases, direct pathologic measurements of mitral valve area agreed exactly with the cross-sectional echocardiographic measurement. Correlation between the mitral E-F slope and mitral valve area by cross-sectional echocardiography (r = 0.56) and catheterization (r = 0.49) was less reliable. Cross-sectional echocardiographic measurement of the mitral valve area correlates well with catheterization in patients with pure mitral stenosis and those with associated regurgitation.

Adult↗
PubMed1977

Echocardiography in valvular vegetations.

Echocardiography represents the only noninvasive technic available for detecting vegetations. In fact, the technic is more sensitive in indentifying these lesions than even angiography. The invasive examination is only capable of detecting very large valvular vegetations. Although echocardiography frequently discloses no abnormalities in patients with clinically suspected or proved bacterial endocarditis, the presence of vegetations can be very helpful in the management of these patients. In addition to identifying vegetations echocardiography can be of great assistance in demonstrating disruption of the affected valve and in identifying that valve which might require surgical replacement.

Aortic Valve↗
PubMed1977

Cross-sectional echocardiographic examination of the interatrial septum.

The interatrial septum has not been readily appreciated by M-mode echocardiography. Cross-sectional echocardiography has the capability of recording the shape and location of the interatrial septum. Real-time cross-sectional echograms using a mechanically oscillating transducer were obtained on 100 consecutive patients. Echocardiographic examination of the left atrium and aorta was obtained in a plane perpendicular to the long axis of the atria. In 15 normal patients and 17 patients with atrial septal defects (ASD) and 51 patients with other forms of heart disease, the interatrial septum was recorded as a linear echo from the aorta to the posterior wall of the left atrium. In six patients who had ostium primum ASDs, the echoes from the interatrial septum disappeared near its expected junction with the interventricular septum. Drop out of echoes in the mid portion of the septum was noted in those patients who had ostium secundum atrial septal defects but this could not be differentiated from normal. These preliminary data indicate that examination of the interatrial septum is feasible and may be specific in those few patients examined so far with ostium primum atrial septal defect. The ability to locate and record the shape of the interatrial septum could have many investigate and clinical uses.

Adolescent↗
PubMed1977

Premature pulmonary valve opening.

Premature opening of the pulmonary valve (opening independent of atrial or ventricular systole) was originally described in a case of sinus of Valsalva rupture into the right atrium. Since that time we have observed five additional cases in which the pulmonary valve opened prematurely. Entities encountered included: 1) constrictive pericarditis; 2) Loeffler's endocarditis; 3) Ebstein's anomaly with tricuspid regurgitation; 4) tricuspid regurgitation following tricuspid valvulectomy, and 5) pulmonary regurgitation accompanied by atrial septal defect. In the first two cases, premature pulmonary valve opening is felt to be due to restriction of diastolic filling of the right ventricle with subsequent early diastolic rise in pressure equalling or exceeding pulmonary artery diastolic pressure. In the latter three cases, the increased volume of blood entering the right ventricle again appeared to result in a rapid rise in initial right ventricular diastolic pressure and to produce premature opening of the pulmonary valve. Premature pulmonary valve opening, therefore, does not appear specific for any particular clinical entity but reflects the relative pressures in the right ventricle and pulmonary artery during diastole.

Adult↗
PubMed1977

Cross-sectional echocardiographic assessment of the severity of aortic stenosis in children.

Real-time, cross-sectional echocardiographic studies of the aortic valve were performed in 28 children with congenital valvular aortic stenosis and in 22 normal subjects. The presence of a stenotic valve was indicated by increase in echo production, abnormal motion pattern, and abnormal systolic position of the valve leaflets. Comparison of the maximum aortic cusp separation (MACS) to calculated aortic valve area yielded an r of 0.91. MACS was then expressed as a percentage of aortic root diameter (AOD) to correct for patient size. In normals MACS averaged 72.7% (range 63-92%) of AOD. With mile aortic stenosis MACS averaged 53.1% of AOD (range 42-62%) (P less than 0.001 vs normal). With moderate and severe aortic stenosis MACS averaged 29.9% of AOD (range 20-35%) (P less than 0.001 vs mild AS). Comparing the ratio MACS/AOD to peak systolic gradient yielded an r of 0.88. Further comparing this ratio to calculated aortic valve area yielded an r of 0.80. Cross-sectional echocardiography can detect the presence of aortic stenosis in children and, by comparing the ratio MACS/AOD, can provide information concerning the severity of the stenotic lesion.

Adolescent↗
PubMed1977

Cross-sectional echocardiographic visualization of the stenotic pulmonary valve.

Real-time, cross-sectional echocardiograms of the pulmonary valve were recorded in 22 patients with valvular pulmonary stenosis (VPS) (14 mild, eight moderate or severe) and 25 normal subjects. Normally during systole the pulmonary leaflet echoes moved rapidly apart and in the fully opened position lay parallel and in close apposition to the margins of the pulmonary artery. In 20 of 22 patients with VPS in whom the pulmonary valve was recorded the systolic configuration of the leaflets, opening pattern of the leaflet echoes, and presence of presystolic doming served to differentiate the stenotic valve from normal. In contrast M-mode recordings of the pulmonary valve were possible in only 12 of these 22 cases (seven mild and five moderate or severe) and suggested VPS in only the five cases with moderate or severe stenosis. Cross-sectional echocardiography offers a direct, noninvasive method for visualizing the stenotic pulmonary valve and should be improvement over the indirect M-mode data.

Adolescent↗