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Biomedical subjects

M L Goris

Publications and source records attributed to M L Goris.

At least 73 records · Page 4Linked to original sources
PubMed1981

ECG gating of thallium-201 myocardial images: effect on detection of ischemic heart disease.

Using the angiographic findings as the standard, we have examined the sensitivity and specificity of ECG-gated static thallium-201 myocardial images in 54 patients undergoing selective coronary arteriography. Gated and nongated images, each in anterior, 45 degrees LAO, and 65 degrees LAO projections, were processed by interpolative background subtraction. They were then analyzed separately by four independent observers who were unaware of patient identity, the results of coronary arteriography, and which studies were gated or nongated. No significant differences were observed between the gated and nongated images regarding sensitivity or specificity, the detection rate for reversible myocardial ischemia, the accuracy of prediction of arteriographic extent of disease, or the degree of inter- or intraobserver variability. We conclude that ECG-gated acquisition of T1-201 images does not produce any significant advantages, at least when interpolative background subtraction is used.

Adult↗
PubMed1979

Reliability and reproducibility of interpretation of 99mtechnetium pyrophosphate myocardial scintigrams.

The interpretations of 156 99mtechnetium pyrophosphate myocardial scintigrams by four observers were analyzed in order to determine the reliability and reproducibility of the subjective process of reading scintigrams. The scintigrams were scored on an integral scale from 0 to 4, depending upon the degree of myocardial radionuclide accumulation, and the site and nature of uptake were specified. Exact agreement upon score was generally poor but approximate concurrence of interpretation was good (90.4 and 92.5% inter- and intra-observer agreement, respectively). There was somewhat less agreement on scintigrams with the higher scores of 3 and 4 (83.3 and 78.0%, respectively). A high level of concurrence upon the differentiation between diffuse and localized uptake, and upon the site of uptake, was found. We conclude that only approximate rather than exact agreement of individual readers' interpretations can be expected in this subjective technique, that scintigrams with higher degrees of radionuclide accumulation produce slightly greater observer disagreement, and that variability of interpretation could account for some of the diagnostic inaccuracy of 99mtechnetium pyrophosphate myocardial scintigraphy.

Angina Pectoris↗
PubMed1979

Cardiac damage produced by direct current countershock applied to the heart.

This study examined the pathophysiology of the myocaridal damage produced by direct current shock over a dose range of 10 to 90 watt-seconds, applied directly to the heart in 26 dosgs. The extent of injury produced was assessed with creatine kinase depletion and light and electron microscopy, and was correlated with in vivo imaging and tissue distributions of the isotopes technetium-99m pyrophosphate and thallium-201. Changes in intramyocardial temperature and regional myocardial blood flow were also measured. Uptake of technetium-99m pyrophosphate occurred exponentially with graded increases in shocks, and this agent was more sensitive than thallium-201 in detecting injury both on imaging and at tissue level. The threshold for significant injury was approximately 30 watt-seconds, and on electron microscopy a characteristic feature was marked dehiscence of the intercalated disks between the damaged myocytes. The use of different-size paddles did not appear to affect the total number of cells damaged. However, with large paddles the injury was more superficial and spread over a wider area. With short time intervals between successive shocks, a greater amount of injury occurred, in part because of a compounding of the thermal component of the damage. Hypothermia can reduce the degree of injury.

Animals↗
PubMed1979

Pyrophosphate retention by previously irradiated renal tissue.

In 3 patients, each of whom had previously had part of one kidney included within the field during radiation therapy, whole-body bone imaging using 99mTc-pyrophosphate showed increased activity in the irradiated renal segment. Possible mechanisms of such renal uptake are discussed.

Adolescent↗
PubMed1978

Value of 111Indium chloride bone marrow scanning in the differential diagnosis of blood count depression in lymphoma.

In patients with Hodgkin's disease or non-Hodgkin's lymphoma, the etiology of low peripheral blood counts is often difficult to determine. Often it is based on the results of a "random" bone marrow biopsy and/or aspirate, plus evaluation of circulating peripheral blood elements. However, these tests may be misleading. The present study evaluates the usefulness of 111Indium chloride bone marrow scanning in conjunction with marrow biopsies in distinguishing intrinsic from extrinsic causes for low peripheral blood counts. Thirty consecutive patients with Hodgkin's disease or non-Hodgkin's lymphoma, presenting with low peripheral blood counts and without any form of antineoplastic treatment for at least 5 weeks, were analyzed. Scan ratings were felt to be clinically accurate in 27 of the 30 patients analyzed (90%). In 18 patients (60%), the scan provided information which was not provided by any other standard test. 111Indium chloride scanning in conjunction with a marrow biopsy appears to be a useful, accurate means of evaluating bone marrow function in patients with depressed peripheral blood counts.

Adolescent↗
PubMed1978

Bone marrow regeneration following large field radiation: influence of volume, age, dose, and time.

Regeneration of bone marrow following radiation only was investigated using 111Indium as a bone scanning agent. Factors which influence local marrow regeneration are dose, age of the patient, and the total amount of the marrow which was irradiated. Time effects are not demonstrated in this study, except to the extent that most regeneration did occur within the first 12 months following irradiation. The most striking finding is the effect of the irradiation volume. Apparent inconsistencies in earlier reports concerning the dose effect could be explained by this effect alone.

Adolescent↗
PubMed1978

Intense concentration of technetium-99m pyrophosphate in the kidneys of children treated with chemotherapeutic drugs for malignant disease.

Seventeen of 265 bone scans in children receiving chemotherapy for various malignant diseases exhibited intense renal parenchymal uptake of radioactivity during bone imaging. In a retrospective analysis, it was learned that uptake occurred when imaging was performed within one week of cancer chemotherapy. It was encountered after injection of cyclophosphamide (P less than 0.05), vincristine (P less than 0.01), and doxorubicin (P less than 0.02). In this series, none of the 265 scans showed intense renal uptake unless the patient received chemotherapeutic drugs in the preceding week. This finding did not seem to result from altered renal function, and the exact cause has not been defined.

Antineoplastic Agents↗
PubMed1977

Technetium-99m pyrophosphate myocardial uptake in patients with stable angina pectoris.

99m-technetium (Tc) pyrophosphate myocardial scintigrams of 55 patients with stable angina pectoris were compared with those of 13 normal subjects. The mean scintigraphic score, obtained by averaging the blinded interpretations of four readers scoring on an integral scale from 0 to 4, was significantly higher for the patients with angina than for the control subjects (1.36 compared with 0.48, P less than 0.001). Among the patients with angina, those who had a prior myocardial infarction had a higher mean scintigraphic grade than those without a previous infarction (1.73 versus 1.15, P less than 0.005), and the mean grade in both groups was higher than that of control subjects (P less than 0.001). Radionuclide uptake was predominantly diffuse in the patients with angina pectoris (70%), although in those with greater uptake accumulation tended to be localized. Three of the 68 subjects had high levels of radionuclide uptake but no clinical evidence of acute myocardial injury. This study demonstrates that excess myocardial accumulation of 99m-Tc pyrophosphate can occur in patients with stable angina pectoris.

Angina Pectoris↗
PubMed1977

Myocardial imaging in a patient with reproducible variant angina.

A unique case is presented of variant angina pectoris with reproducible chest pain and S-T segment elevation in the immediate postexercise period and with normal coronary arteries. Coronary arterial spasm was deomnstrated with arteriography after intravenous administration of ergonivine maleate. Thallium-201 imaging during the pain reproducibility demonstrated malperfusion in the region supplied by the artery with documented spasm.

Adult↗
PubMed1977

Applications of ventilation lung imaging with 81mKrypton.

A method for the evaluation of regional lung ventilation using 81mKr eluted from a rubidium generator is described. The tracer distribution at equilibrium is a function of regional ventilation, not of volumes. The study can be performed on a wide range of patients, including unconscious and mechanically ventilated patients, and can be performed immediately following or concurrently with a perfusion study. Thus, precisely comparable ventilation and perfusion images can be obtained.

Humans↗
PubMed1977

99Technetium bone scanning in experimental osteomyelitis.

A rabbit model of experimental osteomyelitis was used in an attempt to clarify the natural history of bone infection associated with positive scintigraphic and negative radiological findings. In this model a pathogenic strain of Staphylococcus aureus is injected in the proximal metaphysis of the tibia of a rabbit, 15 minutes following the injection of a sclerosing agent. Scintigraphies were performed at 3, 5, 12, and 19 days following this procedure; 99m-Technetium phosphate compounds were used indifferently. On days 5, 12, and 19 a roentgenogram of the lower limbs was taken. Animals were sacrificed at random 6, 14, and 21 days following the procedure. Against expectations, the standard radiological procedure was more sensitive than the scintigraphic technique. The probability of finding a positive bone scintigrapy in the presence of osteomyelitis P(S+/O+) was 15/19 or 0.78. For the roentgenograms P(X+/O+) = 16/17 = 0.94. On pathological review the scintigraphic findings remained unexplained when fibrosis, periosteal reaction, granulocytic infiltration, and new bone formation were considered separately. In half of the cases the early scintigraphies revealed decreased uptake on the affected side, but this finding did not predict whether the final scintigraphy was positive. Finally, positivity was obvious in all cases, and a continuous range from negative to positive could not be documented. Present findings are a characteristic feature of the model. The physiological mechanism remains to be explained by independent measurements of relative bone blood flow made simultaneously with the scintigraphy and other bone tissue specific factors.

Animals↗