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Biomedical subjects

D E Tow

Publications and source records attributed to D E Tow.

At least 37 records · Page 2Linked to original sources
PubMed1987

Radionuclide imaging in a case of tertiary syphilis involving the liver and bones.

Tertiary syphilis is an unusual entity. We have encountered a case of tertiary syphilis of the liver and bone demonstrated by scintigraphy. With liver involvement, the liver scan showed focal defects due to gummas, and distortion due to scarring. Bone involvement was shown as increased cortical activity from periostitis, focal hot spots due to osteomyelitis, and cold defects due to gumma formation. Because syphilis is easily treated, but may not be as readily recognized, the diagnosis should be considered in cases of focal liver or bone disease of obscure etiology.

Adult↗
PubMed1986

SPECT in gallium imaging in a patient with metastatic melanoma.

Gallium imaging may play an important role in both initial evaluation and in follow-up in patients with metastatic melanoma. We present a case where the patient had gallium-avid metastatic melanoma. SPECT proved helpful in the initial evaluation.

Abdominal Neoplasms↗
PubMed1985

The radionuclide evaluation of septal wall motion following coronary bypass surgery.

We investigated the diagnostic accuracy of radionuclide global and regional left ventricular (LV) function after coronary revascularization. A consecutive series of 43 patients was studied. First-pass radionuclide angiograms were performed preoperatively (4 days +/- s.d. 3 days, range 1-18 days) and postoperatively (7 days +/- s.d. 3 days, range 3-19 days). Regional radionuclide LV function was assessed using the two-dimensional display of systole and the three-dimensional ejection fraction image. Electrocardiograms were obtained the day prior to surgery and every 8 h for the first three postoperative days. Creatine kinase (CK) and lactate dehydrogenase (LDH) isoenzymes were obtained the day prior to surgery and every 8 h for the first three postoperative days. In 39 patients who did not develop perioperative myocardial infarction by isoenzyme or ECG criteria, we found that 38 patients showed unchanged or improved global and regional LV function, while one patient without isoenzyme or ECG evidence of perioperative myocardial infarction developed a new septal wall motion abnormality. Thus, the specificity of the radionuclide radioventriculogram for new septal wall motion abnormalities was very high. In four patients who developed isoenzyme and ECG evidence of myocardial infarction, septal wall motion worsened in all four patients while global left ventricular ejection function fell significantly in three patients. Thus, the radionuclide radioventriculogram also had high diagnostic sensitivity. In summary, contrary to past and recent reports, this investigation demonstrated that the radionuclide radioventriculogram can be used to assess global and regional LV function after coronary artery bypass surgery and furthermore, that it reliably indicates the presence of a new postoperative myocardial infarction.

Adult↗
PubMed1985

Non-Q wave perioperative myocardial infarction: assessment of the incidence and severity of regional dysfunction with quantitative two-dimensional echocardiography.

Since the widespread use of hypothermic potassium cardioplegia began, marked reductions in perioperative mortality and the rate of Q wave-associated myocardial infarctions have been noted. No study to date has evaluated whether there has been an equally dramatic improvement in the incidence of postoperative myocardial infarctions unassociated with Q wave development. We used a previously validated quantitative two-dimensional echocardiographic analytic algorithm to determine the incidence and severity of regional wall motion abnormalities (RWMAs) and first-pass radionuclide ventriculography to assess deterioration in global left ventricular function in the four following groups of patients (total n = 65): (1) those with peak postoperative creatine kinase (CK)-MB levels equal to or less than the mean value for patients undergoing coronary artery bypass surgery at our institution (n = 10), (2) those with CK-MB levels between the mean and 1 SD above the mean (n = 10), (3) those with peak CK-MB levels higher than 1 SD above the mean (n = 25), and (4) those with new pathologic Q waves on the postoperative electrocardiogram (n = 20). All patients had electrocardiograms without pathologic Q waves and normal wall motion and ejection fraction by contrast ventriculography before surgery. The incidence of postoperative RWMA by two-dimensional echocardiography for groups 1 through 4 was 0%, 20%, 55%, and 89%, respectively. Percent of abnormal left ventricular segments, wall motion scores, and the deterioration in left ventricular ejection fraction as assessed by radionuclide ventriculography were similar for patients with new RWMAs whether or not new Q waves developed (p = NS for all).(ABSTRACT TRUNCATED AT 250 WORDS)

Arrhythmias, Cardiac↗
PubMed1985

The significance of the late fall in myocardial PCO2 and its relationship to myocardial pH after regional coronary occlusion in the dog.

After acute regional coronary occlusion, myocardial tissue PCO2, as measured by mass spectrometry, rises, reaches a peak, and then gradually falls. This late fall in myocardial tissue PCO2 could be due to (1) a gradual increase in tissue blood flow (and hence improved carbon dioxide washout), (2) a gradual consumption of tissue bicarbonate, (3) a gradual reduction in the production of carbon dioxide due to progressive cellular damage, or (4) an artifact caused by the continued presence of the mass spectrometer probe in the ischemic tissue. To determine which of these four mechanisms is responsible for the late fall in myocardial tissue PCO2, we subjected 27 anesthetized open-chest dogs to 3-hour occlusion of the left anterior descending coronary artery. Both myocardial tissue PCO2 and intramyocardial hydrogen ion concentration were measured in the myocardial segment supplied by the left anterior descending coronary artery. Ten dogs (group 1) were killed after the occlusion (occlusion I), and 11 dogs (group 2) underwent reocclusion (occlusion II) at the same site after a 45-minute period of reflow. Regional myocardial blood flow was measured periodically by the intramural injection of 127Xe. Changes in myocardial tissue PCO2 and hydrogen ion concentration were related to ultrastructural changes in the tissues adjacent to the myocardial tissue PCO2 probe. Regional myocardial blood flow remained unchanged throughout the 3-hour occlusion, ruling out increased carbon dioxide washout as a cause for its late fall. Tissue hydrogen ion concentration, as measured by a new lead glass electrode, correlated well with myocardial tissue PCO2, with the reduction in regional myocardial blood flow, and with ischemic damage assessed histologically. Myocardial hydrogen ion concentration also exhibited a late fall after the occlusion, from a peak of 199.8 +/- 27.8 nmol/liter to 91.9 +/- 12.1 nmol/liter (mean +/- SEM). This ruled out consumption of tissue bicarbonate as the cause for the late fall in myocardial tissue PCO2. Peak rise in myocardial tissue PCO2 after occlusion II (71.2 +/- 7.9 mm Hg) was significantly lower than peak myocardial tissue PCO2 after occlusion I (116.7 +/- 13.9 mm Hg, P less than 0.001). The difference between these latter two values, as well as the magnitude of fall in myocardial tissue PCO2 during occlusion I, related directly to the degree of histological damage observed.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1985

Bone scanning in Waldenstrom's macroglobulinemia.

We present a case report of a remarkably positive bone scan in a patient known to be suffering from Waldenstrom's macroglobulinemia. Although bone involvement in this disease was originally thought not to be present, reports of bone involvement are becoming more frequent. Documenting the presence and extent of bone involvement is important because local palliative radiotherapy and/or orthopedic measures, similar to those recommended for patients suffering from multiple myeloma, may be required to prevent pathologic fractures and patient discomfort.

Aged↗
PubMed1983

Technetium-99m(Sn2+)pyrophosphate in ischemic and infarcted dog myocardium in early stages of acute coronary occlusion: histochemical and tissue-counting comparisons.

We have investigated the pattern of accumulation of Tc-99m(Sn2+)pyrophosphate (Tc-99m PPi) in myocardial tissue of dogs during the early stages of acute occlusion of the left anterior descending coronary artery. Three groups were studied after: (a) 40 min occlusion followed by 6 hr reperfusion (n = 6); (b) 6 hr occlusion followed by one hour reperfusion (n = 5); and (c) 7 hr occlusion with no reperfusion (n = 4). Areas of myocardial infarction were defined with triphenyl-tetrazolium chloride (TTC) staining, and blood flow was determined with 9-mu radioactive microspheres. In Group C uptake in infarcted and peri-infarct areas was not enhanced, most likely owing to low flow. In Group B, with late reperfusion, Tc-99m PPi sequestration was increased in both infarcted and peri-infarcted tissues. In Group A, areas ischemic during occlusion but with normal flow and viability by TTC after 6 hr of reperfusion showed significant uptake of Tc-99m PPi (twice the uptake of nonischemic regions).

Animals↗
PubMed1982

Clinical utility of a multigated modified anterior projection in the detection of left ventricular inferior and apical wall motion abnormalities.

Recent evidence indicates that the left anterior oblique projection (LAO) multigated radionuclide ventriculogram (RVG) underestimates presence and extent of apical and inferior left ventricular (LV) wall motion abnormalities. We investigated, prospectively, the sensitivity and specificity of a modified anterior projection (MAP), which incorporates cephalad tilting. Thirty-three consecutive patients undergoing cardiac catheterization suspected to have coronary artery disease were studied with RVG, using both the MAP and LAO views. LAO views were analyzed using the ejection fraction image (REFI), and the regional ejection fraction (REF) of the inferoapical region. The MAP studies were analyzed using stroke volume image (SVI) to evaluate apical and inferior LV regions. Results were as follows: (Formula: see text), Both intraobserver and interobserver variabilities were comparable to those of conventional angiographic studies used in detection of apical and inferior asynergy. It is concluded that the multigated MAP offers additional information about abnormalities of the LV inferior and apical regions.

Angiography↗
PubMed1982

The interval ejection fraction: a cineangiographic and radionuclide study.

To evaluate the clinical usefulness of the first-third ejection fraction (1/3 EF) for detecting patients with coronary artery disease (CAD), resting contrast ventriculography and first-pass radionuclide angiography with a high-count-rate, multicrystal camera system were performed in 47 subjects: 22 normal controls (group 1) and 25 patients with clinically stable angina pectoris and severe CAD (mean 2.3 vessels) without (group 2, n = 12) and with (group 3, n = 13) resting wall motion abnormalities. By contrast angiography, only group 3 had depressed global EF or 1/3 EF compared with control (global EF: group 1,0.71 +/- 0.09; group 2, 0.67 +/- 0.09 [NS]; group 3,049 +/- 0.05 [p less than 0.01 vs groups 1 and 2]; 1/3 EF: group 1,0.29% +/- 0.06;' group 2, 0.28 +/- 0.05 [NS]; group 3,0.22 +/- 0.05 [p less than 0.02 vs groups 1 and 2]). Whereas 11 of 25 CAD patients had global EF outside the normal range, only two of 25 had depressed 1/3 EF. Both had left ventricular asynergy and a depressed global EF. Studies performed using first-pass radionuclide angiography revealed similar results i.e., only four of 25 CAD patients, all with left ventricular asynergy and depressed global EF, had depressed 1/3 EF values. A wide range of 1/3 EF values was found in normal subjects by both techniques. Thus, the ejection fraction during the first third of systole at rest is of limited value for detecting patients with CAD.

Adult↗
PubMed1982

Resting early peak diastolic filling rate: a sensitive index of myocardial dysfunction in patients with coronary artery disease.

Resting first-pass radionuclide angiocardiography (RNA) was used to derive left-ventricular (LV) peak diastolic filling rates (PFR) in normals (Group 1:N = 12) and in patients with coronary artery disease (CAD), both without (Group 2:N = 27) and with previous myocardial infarction (Group 3:N = 23). Resting peak filling rates were significantly depressed in both Group 2 (1.61 +/- 0.36; p less than 0.01) and Group 3 (1:35 +/- 0.26; p less than 0.001) patients when compared with Group 1, normals (2.14 +/- 0.63). Even though LV systolic function of Group 2 patients was normal and comparable to that in Group 1 (EF = 0.55 +/- 0.06 against EF 0.55 +/- 0.06 NS), diastolic dysfunction [PFR less than 1.61 end diastolic volume/sec (EDV/sec)] was present at rest in 14 of 27 (52%). Depressed PFR values was also seen in 20 of 23 Group 3 patients (87%). It appears that (a) resting PFR is a sensitive and easily obtainable parameter of the diastolic dysfunction associated with CAD; (b) abnormal PFR values are seen in almost all patients with previous myocardial damage, and (c) a significant proportion of CAD patients without any evidence of abnormal systolic function have depressed resting PFR of the LV.

Adult↗
PubMed1982

Clinical use of thrombolytic agents in venous thromboembolism.

The use of thrombolytic agents in venous thromboembolism has been shown to be highly effective. Patients treated with lytic agents show more rapid clot resolution and lung reperfusion and more rapid and greater reversal of the abnormal hemodynamic responses to pulmonary embolism than patients receiving heparin. Moreover, lytic therapy removes thromboemboli more completely from the pulmonary microcirculation, whereas residual thromboemboli tend to accumulate with heparin therapy. In addition, lytic therapy tends to preserve the venous valves, whereas distortion and destruction occur with heparin therapy. Hence, lytic therapy confers a number of short- and long-term benefits not observed with heparin therapy.

Fibrinolytic Agents↗
PubMed1981

Non-invasive measurement of left ventricular function in coronary artery disease. Comparison of first pass radionuclide ventriculography, M-mode echocardiography, and systolic time intervals.

Fifty consecutive patients having had cardiac catheterisation for coronary artery disease also underwent testing by three non-invasive methods commonly employed for assessment of left ventricular function. These included the first pass radionuclide ejection fraction, fractional shortening of the M-mode echocardiographic left ventricular internal dimension, and pre-ejection period/left ventricular ejection time ratio derived from systolic time intervals (PEP/LVET). Linear correlations of these non-invasive measures with cineangiographic ejection fractions were calculated. The first pass radionuclide ejection fraction correlated best. Echocardiograms and systolic time intervals proved less versatile since 11 of 50 echocardiograms were technically not suitable for measurement and 11 of 50 systolic time intervals could not be used because of left ventricular conduction delays. Overall, radionuclide ventriculography proved to be the most accurate and practical of these non-invasive techniques in evaluating left ventricular function in this group of patients with coronary artery disease.

Adult↗
PubMed1981

The effects of large negative intrathoracic pressure on left ventricular function in patients with coronary artery disease.

Using first-pass radionuclide ventriculography, we evaluated the effects of decreases in intrathoracic pressure (Mueller maneuver [M] to -20 to -30 cm H2O) in 14 patients with five patients without coronary artery disease (CAD) and in 12 normal control subjects. In the patients with CAD, control ejection fraction was 0.53 +/- 0.06 (SEM) and control heart rate was 83 +/- 6 beats/min. These did not change during M. In the patients with CAD, control ejection fraction was 0.37 +/- 0.03 and heart rate was 82 +/- 7 beats/min. During M, heart rate did not change, but ejection fraction decreased to 0.33 +/- 0.33 (p less than 0.01). Examination of regional wall motion abnormalities showed akinesis of at least one myocardial segment in nine of 14 patients with CAD, but in none of the patients without CAD, nor in any of the 12 previously studied normal subjects (retrospectively analyzed). These data are consistent with the hypothesis that the Mueller maneuver acts to increase afterload placed on the left ventricle. Furthermore, in patients with CAD, the Mueller maneuver may have induced localized myocardial ischemia or unmasked areas of preexisting marginal function.

Aged↗
PubMed1979

Cardiac imaging with tantalum-178.

Tantalum-178 is a potential tracer for the first transit studies of the heart. It has a short physical half-life (9.3 minutes) and is obtained as a generator product from its long-lived (21.3 days) parent, tungsten-178. First transit studies were performed in the monkey and dog following the intravenous injection of 20 mCi (740 MBq) of tantalum-178. Imaging was performed with a large field of view single crystal camera and a multicrystal camera. Pulmonary dilution curves were derived for the analysis of left-to-right intracardiac shunting and high temporal resolution studies were obtained to assess left ventricular function and to measure left ventricular ejection fraction. The short physical half-life of tantalum-178 permits fraction. The short physical half-life of tantalum-178 permits multiple sequential studies with reduced patient radiation dose compared to the current radionuclide of choice, technetium-99m.

Angiocardiography↗
PubMed1979

Intramural PCO2: a reliable index of the severity of myocardial ischemic injury.

The present study was performed to evaluate the usefulness of changes in intramural oxygen (PmO2) and carbon dioxide (PmCO2) tensions shortly after coronary artery occlusion as indices of the severity of myocardial ischemic injury. In 14 open-chest, anesthetized dogs, a 60-min coronary artery occlusion was performed, during which PmO2 and PMCO2 were measured continuously with a mass spectrometer. Regional myocardial blood flow (RMBF) adjacent to the mass spectrometer probes was measured by the xenon-127 washout technique both before and 30 min after coronary artery occlusion. At the end of 60 min of occlusion, the dogs were killed, and biopsies for histological examination of 1-micron-thick sections were obtained from the tissue surrounding each mass spectometer probe. The decline in PmO2 during the 60-min occlusion bore no relationship either to the severity of ischemic injury as assessed by histological examination, or to the reduction of RMBF. In contrast, the magnitude of rise in PmCO2 during the 60 min of occlusion corresponded closely to both the severity of injury assessed histologically and the reduction of RMBF.

Animals↗
PubMed1979

Cardiac effects of increased lung volume and decreased pleural pressure in man.

The cardiac effects of increased lung volume and/or decreased intrathoracic pressure were assessed by radionuclide angiography in normal male subjects. Increased lung volume alone produced no change in left ventricular (LV) or right ventricular (RV) end-diastolic size. Decreasing intrathoracic pressure to -30 Torr with a Mueller maneuver led to increases in LV end-diastolic and end-systolic volumes, and to increases in RV diastolic area. LV ejection fraction did not change significantly but RV ejection fraction decreased with the Mueller maneuver. Increases in transmural central venous pressure were also noted with the Mueller maneuver. The effects of combining increased lung volume with the Mueller maneuver were similar to those with the Mueller maneuver alone. These effects are consistent with the hypothesis that producing large negative pleural pressures acts to impede left ventricular outflow (i.e., afterloading) and raises the possibility of similar changes during acute attacks of bronchospasm.

Adolescent↗