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Biomedical subjects

D E Tow

Publications and source records attributed to D E Tow.

At least 55 records · Page 3Linked to original sources
PubMed1979

Assessment of left ventricular ejection fraction and volumes by real-time, two-dimensional echocardiography. A comparison of cineangiographic and radionuclide techniques.

Five different algorithms for determining left ventricular (LV) ejection fraction (EF) and volumes from two-dimensional echocardiographic examination (TDE) were compared with standard methods for obtaining EF and volume from x-ray cineangiography (cine) and EF from radionuclide ventriculography (RVG) in 35 patients. Although all methods correlated positively, the degree of correlation varied with the algorithm used. For EF determination, TDE algorithms (especially those using multiple planes of section) were superior to unidimensional algorithms commonly used with M-mode echocardiography. The best algorithm (modified Simpson's rule) correlated well enough with cine EF (r = 0.78; SEE 0.097) and RVG EF (r = 0.75; SEE 0.087) to make clinically useful estimates. TDE volumes also correlated meaningfully with cine end-diastolic and end-systole volumes (r = 084; n = 70) but were associated with a large standard error of the estimate (43 ml) and offered less advantage over unidimensional volume estimates. Quantitative application of TDE appears to be a useful noninvasive method of evaluating LVEF, but is not as useful for estimating LV volumes.

Cineangiography↗
PubMed1979

The appearances of common dental diseases on radionuclide bone images of the jaws.

Radionuclide images of hospital patients were examined for abnormal areas within the jaws. Fourteen of 25 subjects studied showed one or more abnormal image areas, most of which were attributable to common dental lesions revealed by oral examinations. The lesions detectable on images included healing bone sites, periodontal and pulpal disease, residual osteitis and irritations caused by ill-fitting dentures.

Adult↗
PubMed1978

Bone scan in dental diseases.

Bone images of the jaws and related dental structures were obtained in 25 patients undergoing skeletal surveys. The upper and lower jaws were divided into eight quadrants to facilitate comparisons between scintigraphic image findings and the results of dental examination. Fourteen of these 25 patients had at least one jaw quadrant with a positive image. The areas of positive uptake correlated well with dental examination findings, which included healing extraction sites and common dental diseases, such as pulpal and periodontal infections and irritations from ill-fitting dentures. The potential usefulness of bone imaging as an adjunct in dental diagnosis is discussed.

Adult↗
PubMed1977

Diagnosis of acute myocardial infarction in patients undergoing open heart surgery: a comparison of serial myocardial imaging with cardiac enzymes, electrocardiography, and vectorcardiography.

In 44 consecutive patients undergoing elective open heart surgery (OHS), serial electrocardiograms (ECG), vectorcardiograms (VCG), serum CPK, cardiac isoenzymes (CPKMB), and myocardial images using Tc-99m pyrophosphate were obtained, before and after the operation, for the detection of acute myocardial infarction (AMI). Twenty-nine patients developed one or more positive tests postoperatively. Two patients had positive myocardial scintiscans; both had other evidence of infarction. Conversely, the appearance of CPKMB, or new ECG and VCG changes, occurred frequently without evidence of infarction, and were not associated with the development of a positive scintiscan. The results show that false-negative results are infrequent in patients imaged early after OHS, and that cardiac surgical procedures do not cause a high incidence of false-positive scintigrams. Consequently, radionuclide imaging for AMI offers an important adjunct for excluding acute infarction following open heart surgery.

Cardiac Surgical Procedures↗
PubMed1976

Clinical appraisal of current nuclear and other noninvasive cardiac diagnostic techniques.

At a time of rapid increases in the cost of medical care and the application of complex invasive procedures to cardiovascular diagnosis, the use of noninvasive methods has aroused interest. This report discusses the usefulness and limitations of various noninvasive diagnostic methods including nuclear medicine techniques, echocardiography, exercise electrocardiography and determination of systolic time intervals. Emphasis is placed on the applicability of these methods to specific disease processes (such as ischemic heart disease, cardiac valve disease, pulmonary embolic disease), their relative merits, future potential and present shortcomings.

Aortic Aneurysm↗
PubMed1976

Deep venous thrombosis in acute spinal cord injury: a comparison of 125I fibrinogen leg scanning, impedance plethysmography and venography.

Twenty acute spinal cord injury patients were surveyed for deep venous thrombosis (DVT) by 125I fibrinogen leg scanning, impedance plethysmography (IPG), and venography. Leg scanning was a more sensitive indicator of thrombotic events than IPG or venography. IPG was a reliable indicator of accumulated thrombosis. The incidence of dvt assessed by leg scanning alone was 100 per cent. Its occurrence as determined by either of the screening techniques was found to be considerably greater than those of previous reports.

Adult↗
PubMed1976

Noninvasive detection of intracardiac thrombosis: 131-I fibrinogen cardiac survey.

Cardiac survey following administration of 131-1 autologous fibrinogen is a noninvasive technique for the detection of intracardiac thrombosis. Fibrinogen is isolated from plasma by a rapid salting-out method with ammonium sulfate and is iodinated with chloramine T. The purity of 131-fibrinogen, expressed as clottable radioactivity, is greater than 90%. Cardiac survey consisting of serial gamma camera imaging or rectilinear scanning after intravenous administration of 131-I fibrinogen was conducted in dogs with freshly induced thromobosis of the left atrial appendage. An accumulation of radioactivity was detectable in the area of the left atrium and confirmed in each of nine dogs sacrificed. Similarly, 20 patients with heart disease predisposing to intracardiac thrombosis were surveyed. Eight of nine patients with positive studies and 11 of 11 with negative studies were confirmed subsequently at surgery or autopsy. Cardiac survey with 131-I fibrinogen is a simple and noninvasive method of detecting intracardiac thrombosis.

Animals↗
PubMed1976

Relative accretion of 99mTc-polyphosphate by forming and resorbing bone systems in rats: its significance in the pathologic basis of bone scanning.

The relative roles of osteogenesis andd osteolysis in the production of positive radionuclide images of skeletal lesions were investigated. The uptake of 99mTc-polyphosphate (Tc-PP) by each process was measured in an animal model that permitted bone formation and resorption to be studied independently. Ten rats received intramuscular implants of bone-forming demineralized matrix (DM) and resorbing devitalized bone (DV). Radiographs and Tc-PP scintiscans were made each week thereafter. At 6-10 weeks, the implants and normal bone samples were removed, counted for 99mTc, and examined histologically. The uptake of Tc-PP BY DM implants was first detected on images made 3 weeks after implanatation, and by DV implants, 1-2 weeks later. Serial radiography showed progressive calcification of DM an resorption of DV implants. Microscopic examinations of undecalcified sections, stained with a modified Goldner preparation, revealed vital-bone formation in the DM implants and osteoclastic resorption in the DV. Activity counts per gram of DM and DV implants were, respectively, 200% and 90% that of normal bone. Since only the bone-forming system (DM) accumulated Tc-PP at greater than normal concentrations, this study indicates that positive bone images of osteolytic lesions solely reflect compensatory osteogenic responses.

Animals↗
PubMed1975

Scintigraphic demonstration of abscesses with radioactive gallium labeled leukocytes.

Autologous peripheral blood leukocytes, labeled in vitro with 67Ga citrate, have been studied in 20 patients as a radioactive carrier for the scintigraphic visualization of septic inflammatory areas. 67Ga citrate was added to venous whole blood; following incubation, the blood was centrifugated, and the packed cells were reinfused. Scintiscans were obtained four and 24 hours later. The inflammatory process was demonstrated in nine of nine patients with confirmed sepsis. Eleven patients without sepsis had normal scans. There were no false-negative scans and one-false-positive scan. The selective accumulation of the gallium labeled leukocytes in areas of septic inflammation was sufficient to allow scintigraphic demonstration of the inflammatory area.

Abscess↗
PubMed1975

Autologous radioiodinated fibrinogen, simplified.

A method for the rapid preparation of radioiodinated autologous fibrinogen has been improved. Plasma is separated from cells by a single centrifugation. Fibrinogen is isolated in two salting-out steps at a 1:4 dilution of plasma and 22.5% saturated ammonium sulfate. Iodination is accomplished with chloramine T at a chloramine T-to-fibrinogen molar ratio of 12:1. Free iodide is removed by a single dilution and salting-out step at 29% saturated ammonium sulfate. Preparation time is about 1 hr; clottable radioactivity is 90-95%. Denaturation due to storage is undetectable at 6 weeks. Advantages of this procedure are (A) a short preparation time and (B) a purified autologous radioiodinated fibrinogen preparation.

Fibrinogen↗