sodium-pertechnetate-tc-99m and Arterial-Occlusive-Diseases

Pertechnegas, a variant of technegas, is a fine, dry aerosol formed when technetium-99m pertechnetate is vaporized in a technegas generator under appropriate conditions. After inhalation, the aerosol is deposited almost entirely on the surfaces of terminal respiratory structures. Unlike technegas, however, pertechnegas crosses the alveolar-capillary membrane and leaves the lung through the pulmonary circulation. To demonstrate prolonged retention of pertechnegas in regions of lung supplied by an occluded pulmonary artery, 12 pulmonary arterial occlusions were experimentally produced in two dogs. After inhalation of pertechnegas, a transient focus of increased pulmonary radioactivity was seen in 11 occlusions; 10 of these 11 foci were easily confirmed by means of subsequent perfusion scintigraphy. All 11 foci of retained pertechnegas corresponded to the location of the non-perfused lung. Thus, it is possible to identify ischemic lung with focal retention of pertechnegas (a finding that indicates preserved ventilation but diminished perfusion) by use of a single examination.

Topics: Aerosols; Animals; Arterial Occlusive Diseases; Dogs; Pulmonary Artery; Radionuclide Imaging; Sodium Pertechnetate Tc 99m

The assessment of the intracranial hemodynamic consequences of obstructive lesions of the carotid artery by measuring resting rCBF is inadequate because cerebral blood flow may remain constant in spite of significant drops in the intraluminal pressure due to autoregulation. Moreover, flow may be permanently decreased following cerebral infarction, even if the arterial anatomical conditions have resumed their normal state because of the decreased metabolic demand of an infarcted area. Measurement of the regional cerebral blood volume (rCBV) helps with the hemodynamic assessment of these conditions, since there is a linear and inverse relationship between intraarterial pressure and intracranial blood volume. In 24 patients exhibiting various carotid and ischemic brain lesions we studied both rCBF and rCBV. The latter is a comparative measure between hemispheres obtained by single photon emission tomography after autotransfusion of 99m Technetium labeled erythrocytes. There was no correlation between rCBF and clinical status, CT scan or arterial lesions. There was no correlation between rCBV and clinical status or CT scan. There was, however, an interesting correlation between rCBV and the severity of the arterial lesion. The rCBV was symmetrical in all patients with normal or moderately stenotic carotid arteries before and after operation. In some patients with severe unilateral stenosis or occlusion, there was a significant relative increase of rCBV in the hemisphere downstream from the lesion, which disappeared after surgery (endarterectomy or extra-intracranial bypass). In some patients with severe and bilateral carotid lesions, we noted an asymmetry in rCBV that disappeared after a unilateral operation. Other patients with similar lesions develop asymmetry only after an operation that resulted in a relative increase in rCBV in the hemisphere supplied by the non-operated artery. In conclusion analysis of these results suggests that in this series of patients, rCBV modifications were the consequence of cerebral autoregulation distal to the arterial lesions and provided satisfactory assessment of hemodynamic improvement after surgical repair.

Topics: Adult; Aged; Arterial Occlusive Diseases; Blood Volume; Carotid Artery Diseases; Carotid Artery, Internal; Cerebrovascular Circulation; Female; Humans; Male; Middle Aged; Sodium Pertechnetate Tc 99m; Tomography, Emission-Computed; Xenon Radioisotopes

Forty-four patients with symptoms of lower limb arterial insufficiency were examined by radionuclide angiography using 99Tcm in vivo red cell labelling and by contrast aortography. The results of the study indicate that radionuclide angiography may well have a useful role to play in determining the type of contrast study most appropriate for delineating the aortic-iliac segment.

Topics: Adult; Aged; Aorta, Abdominal; Aortic Diseases; Aortography; Arterial Occlusive Diseases; Erythrocytes; Female; Humans; Iliac Artery; Leg; Male; Middle Aged; Radionuclide Imaging; Sodium Pertechnetate Tc 99m

The use of planar radionuclide ventriculography to evaluate global and segmental ventricular function is limited by the superimposition of structures in some projections and the gross segmental resolution of the planar technique. Preliminary reports have suggested the feasibility of tomographic gated radionuclide ventriculography with rotating detector systems. This study tested the hypotheses that 1) tomographic radionuclide ventriculography detects segmental dysfunction at rest not identified with multiview planar studies and single plane contrast ventriculography, and 2) ventricular volumes and ejection fraction calculated from these studies provide data similar to those obtained with angiography and planar radionuclide ventriculography. Gated blood pool tomograms were acquired over 180 degrees at 15 frames per cardiac cycle during the initial 90% of the cardiac cycle. Compared with the multiview planar technique tomographic ventriculography showed an increased sensitivity for detecting left ventricular segments with significant coronary artery stenosis (97 versus 74%, p less than 0.025) without any loss in specificity. Compared with both planar radionuclide and contrast ventriculography, tomographic radionuclide ventriculography also detected more noninfarcted left ventricular segments supplied by stenosed coronary arteries (81 versus 39 and 32%, respectively, p less than 0.01). Tomographic radionuclide ventriculographic measurements of left ventricular volumes and ejection fraction showed close correlations with angiographic and planar radionuclide determinations. Gated blood pool tomography is a sensitive method for the evaluation of segmental wall motion and an accurate method for the measurement of global left ventricular volumes and ejection fraction.

Topics: Adult; Aged; Arterial Occlusive Diseases; Cardiac Catheterization; Cardiac Volume; Coronary Disease; Coronary Vessels; Erythrocytes; Female; Humans; Male; Middle Aged; Myocardial Contraction; Sodium Pertechnetate Tc 99m; Stroke Volume; Tomography, Emission-Computed

Topics: Adult; Arterial Occlusive Diseases; Carotid Artery Diseases; Carotid Artery, Internal; Cerebral Arterial Diseases; Female; Follow-Up Studies; Humans; Male; Radionuclide Imaging; Sodium Pertechnetate Tc 99m

At below-knee amputation for arterial insufficiency in 31 patients, the muscle blood flow of quadriceps and triceps surae was measured by clearance of 99mTc pertechnetate pre- and postoperatively. In 15 patients, myoplastic amputation was performed and in 16 patients the medullary cavity of the tibial stump was plugged with cortex of the removed bone as well. Plugging caused a two-third increase in muscle blood flow.

Topics: Aged; Amputation Stumps; Amputation, Surgical; Arterial Occlusive Diseases; Blood Flow Velocity; Humans; Ischemia; Leg; Middle Aged; Muscles; Radionuclide Imaging; Sodium Pertechnetate Tc 99m; Tibia

Radionuclide angiography (angioscintigraphy) of the iliac arteries was performed in 173 patients consecutively referred for arterial insufficiency of the legs. In 83 of the patients femoral angiography was also performed. The interobserver variation was evaluated by the agreement indices, kappa (K) and weighted kappa (Kw). For angiography the interobserver agreement was high (K and Kw 0.65 and 0.77 respectively). For angioscintigraphy the agreement between observers was fair (K = 0.52, Kw = 0.68), and equal to the intraobserver agreement (K = 0.55, Kw = 0.65). The comparison between angioscintigraphy and angiography gave K-values of 0.22-0.31 and Kw-values of 0.37-0.48. The nosographic sensitivity of angioscintigraphy was 61%, the nosographic specificity was 93%, and the predictive value for both a positive and a negative test was 83%. The prevalence of occlusion or severe stenosis was 34%. Inguinal pulse palpation detected 48% of iliac occlusions. It is concluded that the reliability of angioscintigraphy in the diagnosis of iliac arterial occlusive disease is acceptable for a non-invasive, rapid, inexpensive and widely available screening procedure. Although anatomical details are not visualized the information obtained is useful for the detailed planning and choice of subsequent diagnostic and therapeutic procedures. The method is well suited for repeat studies and may be modified to include the femoral arteries.

Topics: Adult; Aged; Arterial Occlusive Diseases; Evaluation Studies as Topic; Female; Humans; Iliac Artery; Injections, Intravenous; Male; Middle Aged; Radionuclide Imaging; Sodium Pertechnetate Tc 99m; Technetium

Topics: Angiography; Arterial Occlusive Diseases; Computers; Humans; Sodium Pertechnetate Tc 99m; Technetium

The large elastic arteries, such as the carotids, pulsate (expand and contract) in synchrony with the heart beat. These pulsations should be reduced by significant stenosis. This hypothesis was studied in 15 men by obtaining sequential ECG-gated labeled blood-pool images of these vessels in anterior and lateral oblique views. These were computer processed by a functional program that displays each pixel with an intensity proportional to its change in activity level during the cardiac cycle. Blank areas indicated lack of pulsation and were correlated with angiographic studies. The blank skip areas were present when there was 50% or greater narrowing in arterial diameter (94% sensitivity) but were not seen in patients with normal or minimally diseased vessels (25% or less narrowing). They were present inconsistently in the four vessels with 25 to 50% narrowing.

Topics: Aged; Angiography; Arterial Occlusive Diseases; Carotid Artery Diseases; Electrocardiography; Erythrocytes; Humans; Male; Middle Aged; Polyphosphates; Pulse; Radionuclide Imaging; Sodium Pertechnetate Tc 99m; Technetium; Tin Polyphosphates

Before undertaking a femoro-popliteal bypass graft it is important to know whether the popliteal artery is patent to receive the distal end of the graft. Patency was assessed in 48 studies of 46 patients with peripheral vascular disease by radio-nuclide angiography. The procedure consists of imaging the popliteal arteries using a gamma camera after a bolus injection of 99mTc-sodium pertechnetate. The radio-nuclide angiograms were compared with the operative X-ray popliteal angiograms. Reliable information was obtained from the radio-nuclide images regarding the patency of the popliteal artery provided a femoral pulse was present. Quantitative data generated from the activity time curves were of no value in assessment of the patency of the popliteal arteries.

Topics: Arterial Occlusive Diseases; Femur; Humans; Popliteal Artery; Radiography; Radionuclide Imaging; Sodium Pertechnetate Tc 99m; Technetium

Topics: Adolescent; Arterial Occlusive Diseases; Brain; Cerebrovascular Circulation; Child; Child, Preschool; Humans; Moyamoya Disease; Radionuclide Imaging; Sodium Pertechnetate Tc 99m; Technetium

False positive dynamic imaging of the cerebral circulation simulating vascular occlusive disease resulted from a clinically insignificant congenital variation in several patients at our institutions. The anomaly consisted of the asymmetrical caliber of the internal carotid and proximal anterior cerebral arteries. The 1 mm difference in the diameter of the internal carotid arteries was sufficient to be appreciated on dynamic imaging. The frequency of this anomaly was found to be 5% in a series of 200 bilateral carotid angiograms.

Topics: Adult; Arterial Occlusive Diseases; Brain; Carotid Artery, Internal; Cerebral Angiography; Cerebral Arteries; Cerebrovascular Circulation; False Positive Reactions; Humans; Male; Radionuclide Imaging; Regional Blood Flow; Seizures; Sodium Pertechnetate Tc 99m; Technetium