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Biomedical subjects

A Gottschalk

Publications and source records attributed to A Gottschalk.

At least 163 records · Page 9Linked to original sources
PubMed1978

Technetium-99m stannous pyrophosphate imaging of experimental infective endocarditis.

Technetium-99m stannous pyrophosphate (99mTc-PYP) cardiac scintigraphy was performed in 15 rabbits with experimental Streptococcus sanguis aortic valve infective endocarditis. The animals were imaged five to seven days after the administration of bacteria, and in each case abnormal accumulation of the tracer was visualized in the region of the aortic valve. Three types of cardiac scintigraphic patterns were demonstrated: focal, multifocal and extensive, each correlating well with the anatomical extent of the lesion as defined by gross pathology. Tissue distribution studies demonstrated a 30 +/- 5.3 (mean +/- SEM) fold excess of radionuclide uptake in the infective endocarditis lesion compared with that of normal myocardium. Imaging of excised hearts from four animals showed an excellent correlation with in vivo imaging as well as gross pathology. Five animals with nonbacterial thrombotic aortic valve endocarditis demonstrated similar scintigraphic and tissue distribution results. In contrast, four normal animals failed to demonstrate abnormal 99mTc-PYP cardiac scintigrams or tissue uptake. This study demonstrates that 99mTc-PYP cardiac scintigraphy is a sensitive technique to detect experimental aortic valve endocarditis.

Animals↗
PubMed1978

Assessment of cardiac performance with quantitative radionuclide angiocardiography. Effects of oral propranolol on global and regional left ventricular function in coronary artery disease.

The effect of incremental dosages of oral propranolol (mean peak dose of 165 +/- 13 mg/day) of left ventricular ejection fraction, ejection rate and regional wall motion was studied sequentially in 22 stable, resting patients with coronary artery disease using a geometry-independent first-pass radionuclide angiocardiographic technique. All patients improved clinically, in association with a fall in heart rate and therapeutic serum propranolol levels. No significant changes were noted in ejection fraction, ejection rate or regional wall motion. No patient developed a new regional wall motion disturbance. Thus, oral propranolol administered at clinically effective antianginal dosages in patients with stable coronary artery disease does not appear to have significant deleterious effects on resting left ventricular performance.

Administration, Oral↗
PubMed1978

Dual radionuclide study of acute myocardial infarction: comparison of thallium-201 and technetium-99m stannous prophosphate imaging in man.

We evaluated dual imaging with thalium-201 (201TI) and technetium-99m (99mTc) pyrophosphate in 80 patients with documented acute myocardial infarction (55 transmural, 25 nontransmural infarction). Color-coded isocount display of 201TI images was essential for interpretation in 16 patients. Combined 201 TI and 99mTc-pyrophosphate imaging for infarct detection was 100% sensitive; however, either was falsely negative in 12 of 80 patients. False-negative individual 201TI or 99mTc-pyrophosphate infarct images were most common in patients with small infacts or left ventricular hypertrophy. Thallium-201 images correctly localized the site of acute transmural infarction in all 51 patients with a positive image, while 99mTc-pyrophosphate localized the site of infarction in 49 of 53 with an abnormal image. Comparison of the size of the imaged infarct region revealed size discordance in 25 of 49 patinets, with 99mTc-pyrophosphate larger in 21 of 49 and 201TI larger in only four of 49. Thus dual radionuclide imaging provides definition of the presence and location of acute myocardial infarction.

Acute Disease↗
PubMed1978

Sequential radionuclide assessment of left and right ventricular performance after acute transmural myocardial infarction.

Ventricular performance was evaluated sequentially in 31 patients with uncomplicated acute transmural myocardial infarction (13 anterior and 18 inferior). Left ventricular ejection fraction, ejection rate, regional wall motion, and right ventricular ejection fraction were ascertained using first-pass radionuclide angiocardiography on four occasions during hospitalization. Inferior infarction resulted in a greater reduction in right ventricular ejection fraction than anterior infarction (mean +/- SEM; 48 +/- 2 versus 56 +/- 2%, P less than 0.01). In contrast, in anterior infarction there was greater depression of left ventricular ejection fraction than in inferior infarction (34 +/- 3 versus 50 +/- 3%, P less than 0.01). From initial to discharge studies, there was no significant change in global performance or regional wall motion in either group. These data show that the location of transmural infarction has a profound effect upon the magnitude of right and left ventricular dysfunction. In addition, ventricular systolic performance remains relatively stable during the hospital phase of uncomplicated transmural myocardial infarction.

Acute Disease↗
PubMed1978

Comparison of the Anger tomographic scanner and the 15-in. scintillation camera for gallium imaging.

The Anger longitudinal emission multiplane tomoscanner and a 15-in. Anger camera with multipeak spectroscopic capability were compared in a series of 51 patients. The tomoscanner was preferred in 49%, the camera in 12%, and 39% were equivalent. The tomoscanner preference is statistically significant (p less than .025). These data support the conclusion that the Anger multiplane tomographic scanner is the instrument of choice for gallium-67 imaging.

Gallium↗
PubMed1977

Recent advances in cancer diagnosis with nuclear medicine techniques.

Recent progress in cancer detection in nuclear medicine has been significant and encouraging. Three main trends are responsible. First, techniques of imaging have improved, often in conjunction with the development of new and better imaging devices. Secondly, new radiopharmaceuticals are being investigated. Finally, interaction with other imaging modalities has started. In general, this yields complementary information further refining the diagnostic process.

Antibodies, Neoplasm↗
PubMed1977

Scintigraphic evaluation of lymphoma: a comparative study of 67Ga-citrate and 111In-Bleomycin.

Sequential whole-body scans with both 67Ga-citrate and 111In-bleomycin were performed for 14 patients undergoing staging for Hodgkin's disease or other lymphomas. A comparison or these scans gave a sensitivity in detecting the pathologically-proved tumor sites of 84% for 67Ga-citrate and only 56% for 111In-bleomycin. In 12 patients, the gallium scan demonstrated the lesions more clearly; in the others, the uptake of the two radionuclides was equal. In no case was a clinically diagnosed or histologically proved lesion identified by 111In-bleomycin that was not also demonstrated by 67Ga-citrate. 111In-bleomycin does not complement the 67Ga-citrate scan in the scintigraphic evaluation of lymphomas.

Adolescent↗
PubMed1977

Gray scale ultrasound and isotope scanning: complementary techniques for imaging the liver.

Technical advances in gray scale ultrasound have led to better signal-to-noise ratios and improved resolution. A display of the texture of the liver is now possible, making ultrasound an important complementary technique to radioisotope scanning. In the positive radioisotope scan, ultrasound permits differentiation of isotopically cold areas into neoplasms, benign cysts, and abscesses. In addition, when the radioisotope scan is equivocal, ultrasound is invaluable in differentiating normal variants from disease states. Dilated intrahepatic ducts can also be identified. Examples of the use of ultrasound in defining radioisotope abnormalities are presented.

Adult↗
PubMed1976

A unified radiological approach to the detection of skeletal metastases.

Radiographic bone surveys and radionuclide images, the principal methods of detection of skeletal metastases, have traditionally been treated as separate entities. Since their interpretation is reltaed, we attempted to determine the practicability of a unified radiological approach which employs both methods. All consultation requests for "skeletal surveys" or bone scans were reviewed, and an appropriate examination was "tailored" for each patient. During the inital four-month period, 141 patients were examined. Comparison of the final "tailored" examination with the original consultation request indicated that, without radiological guidance, excessive (18%), and inappropriate or inadequate (27%) examinations were ordered in many cases. The unified approach has proven to be feasible and desirable, resulting in a significant reduction of inappropriate examinations.

Bone Neoplasms↗
PubMed1976

Nuclear imaging: a new dimension.

Tomographic techniques used in radiology have also found an application in nuclear medicine. Longtitudinal tomography blurs but does not eliminate structures outside the plane of interest. Transverse tomography eliminates out-of-plane structures, making accurate imaging possible. Positron imaging devices are well suited for transverse tomography because of their high spatial resolution and depth-independent response, but devices using a scintillation camera can visualize large volumes and are not restricted to the use of positron emitters.

Humans↗
PubMed1976

The usefulness of the posterior oblique views in perfusion lung imaging.

A total of 116 perfusion lung images, with and without posterior oblique views, were compared by four trained observers. There was a significant increase in the number of perfusion defects detected when the posterior oblique views were included. Pairs of projections of 89 lung images were read by the four observers. The percentage of correct readings for the posterior oblique views was 78% compared with 63% and 56% for the lateral views and AP views, respectively. Inclusion of the posterior oblique views as a routine part of the examination is recommended.

Humans↗
PubMed1976

Evaluation of liposome-entrapped radioactive tracers as scanning agents. Part 1: Organ distribution of liposome (99mTc-DTPA) in mice.

We describe the use of liposomes as a delivery system for radiopharmaceutical localization. Liposomes [99mTc-DTPA] were injected intravenously in mice and showed preferential uptake in the liver and spleen. There was a steady decline of activity in all organs, suggestive of destruction of liposomes with subsequent release of 99mTc-DTPA into the circulation. Alteration of uptake from liver to spleen, lung, and bone marrow was achieved by prior loading of the circulation with nonradioactive liposomes. The same effect was produced in dogs and demonstrated with scintigraphy. We also showed scintigraphically in dogs how 99mTc-DTPA, when administered entrapped in liposomes, follows the pattern of distribution of liposomes. Liposomes seem to be suitable carriers for radiopharmaceuticals. Further studies should show the possibility of directing liposomes to specific targets.

Animals↗
PubMed1975

Splenic mobility and its effect on estimates of splenic mass.

In 47 patients the posterior radionuclide views of the spleen in supine and prone positions were evaluated for difference in splenic contour and calculated splenic weight as the patient's position was changed from supine to prone. A significant change in splenic contour was found in almost 50% of the cases. Values for the mass of the spleen varied by a mean of 36% with a range of plus 195 to minus 79%. The differences are attributed primarily to changes in the position of the spleen and liver within the abdomen.

Humans↗