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Biomedical subjects

P Georgi

Publications and source records attributed to P Georgi.

At least 19 recordsLinked to original sources
PubMed1992

[Thyroglobulin, 131I-whole body scintigraphy and risk factors in the follow-up of differentiated thyroid cancer].

Results of 131I whole body scans and measurements of thyroglobulin (Tg) in the follow-up of 85 patients with differentiated thyroid cancer were analysed in a retrospective study. All patients were assumed to be tumor-free after therapy. During follow-up, cancer recurrence was observed in 11 patients. Out of 24 131I scans performed for suspected recurrence, cancer was localized in 5. Out of 71 routinely performed 131I scans and Tg measurements during hormone withdrawal, new pathologies were observed in each of two cases one year after the last therapy. 10 out of 11 tumor recurrences were observed in a high-risk group of 40 patients with follicular histology or stage III or IV (UICC 1987). One recurrence occurred in a low-risk group of 41 patients with papillary histology and UICC stage I or II. Later than one year after therapy no recurrence was observed in any patient who belonged to the low-risk group. These results indicate that 131I scans and Tg measurements under endogenous TSH stimulation are necessary in cases of suspected recurrences and probably on a routine basis one year after the last therapy in all patients. In the event of an inconspicuous further course this diagnostic procedure should be restricted to special high-risk groups. Using a cut-off level of 5 ng/ml as compared to 10 ng/ml, the number of false-negative Tg results under suppressive therapy decreased clearly whereas that of the "false-positive" results increased less pronounced.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗
PubMed1990

Regional cerebral blood flow in endogenous psychoses, measured by 99mTc HMPAO-SPECT.

The aim of this pilot study was to determine the sensitivity of HMPAO-Single Photon Emission Computed Tomography (SPECT), a new technique for determining cerebral blood flow. 7 RDC-schizophrenics, 5 schizoaffectives and 6 depressives were investigated after remission of the psychosis. It appeared that in the schizophrenics the blood flow was significantly reduced in the left anterior region in the infraventricular and ventricular section when compared with the depressives. This finding is discussed here. Apparently, HMPAO-SPECT is another valuable technique for investigating cerebral blood flow.

Cerebrovascular Circulation↗
PubMed1990

Pharmacokinetics of technetium-99m-MAG3 in humans.

Technetium-99m-mercaptoacetylglycylglycylglycine (99mTc-MAG3) is introduced to replace o-iodohippurate (OIH) for renal function studies. For interpretation of clinical findings, extensive pharmacokinetic studies were performed on patients. These showed that 99mTc-MAG3, compared with OIH, has a higher plasma-protein binding, an essentially higher intravascular concentration, a smaller volume of distribution and, with practically identical biologic half-lives, a correspondingly lower clearance. Simultaneous steady-state measurements resulted in a 1.5-fold higher clearance of OIH than of 99mTc-MAG3 (n = 124). Competitive inhibition of the tubular transport system by p-aminohippurate (PAH) (20 patients) revealed a distinctly higher suppression of the 99mTc-MAG3 clearance than of OIH which indicates a lower affinity of the 99mTc complex to the tubular cell. The plasma extraction efficiencies of both agents, measured during surgery (n = 5), did not indicate an extrarenal elimination of 99mTc-MAG3. This new radiopharmaceutical is a pragmatic alternative to OIH and offers advantages not only for scintigraphic imaging but is also suited for quantitative renal function studies.

Humans↗
PubMed1990

Current status of immunoscintigraphy in colorectal cancer--results of 5 years' clinical experiences.

In 100 patients with suspected colorectal cancer, findings of conventional diagnostic methods were compared with immunoscintigraphy results. In a first trial 131-J-labelled F (ab') 2-fragments against CEA and CA 19-9 were used in 42 patients. Evidence was confirmed by surgical exploration in 69% of cases and by close follow-up examination in 31%. In a second trial 58 patients were included, and 81% of these were explored surgically. Conventional diagnostic methods achieved better results in both series in imaging liver and extrahepatic tumor manifestations, and in both series immunoscintigraphy was especially disappointing with regard to extrahepatic tumor diagnosis (sensitivity 23% and 38%, respectively). Accuracy could not be improved by technical modifications such as change of antibodies, radiolabels or imaging techniques. The value of immunoscintigraphy as a helpful tool for the operative management of metastatic or recurrent colorectal cancer must, therefore, be viewed critically.

Antibodies, Monoclonal↗
PubMed1989

The value of immunoscintigraphy for the operative retreatment of colorectal cancer. Limitations of a new diagnostic method.

In 42 patients with suspected recurrent colorectal cancer, results of conventional diagnostic methods were compared with those of immunoscintigraphy. In 69% of all cases, the intraoperative findings of a second-look operation served for validation, whereas in 31% close follow-up was used. Recurrent tumors were successfully localized in 83% of patients by conventional methods, whereas immunoscintigraphy was expressive in 57% of cases. Immunoscintigraphy was disappointing especially because of its low sensitivity (23%) and low predictive value (positive, 33%; negative, 37%) with regard to successful diagnosis of extrahepatic tumors compared with the results of conventional methods (77% sensitivity; positive, 94%; negative, 79%). The rate of false-positive results was relatively high with immunoscintigraphy (n = 12), 83% of which were related to extrahepatic recurrent tumors. The value of immunoscintigraphy using an immunococktail of 131-J-labeled F(ab')2 fragments of monoclonal antibodies against CEA, with Ca 19-9 as an additional diagnostic tool for early detection of recurrent colorectal cancer, must therefore be viewed critically.

Antibodies, Monoclonal↗
PubMed1989

[Hyperthyroidism caused by a hormone-producing follicular thyroid cancer].

A well differentiated carcinoma of the thyroid is usually less productive with respect to thyroid hormones than normal thyroid tissue. Very rarely, it happens though that a metastatic follicular carcinoma of the thyroid produces hyperthyroidism as the following example illustrates. In our patient with follicular thyroid carcinoma the radioiodine scan demonstrated an increased uptake of 123I in the right thyroid lobe but also in a lung metastasis, even before thyroidectomy. In contrast, the iodine uptake of the left - normal - thyroid lobe was suppressed. Following thyroidectomy the levels of the thyroid hormones were normal and only dropped into the hypothyroid range after the beginning of the therapy with radioiodine. Hence we conclude that the metastases of a thyroid carcinoma can attain the hormone secretion of a normal thyroid gland and take up more radioiodine than normal thyroid tissue.

Adenocarcinoma↗
PubMed1989

Scar or recurrent rectal cancer. Positron emission tomography is more helpful for diagnosis than immunoscintigraphy.

We used positron emission tomography and fludeoxyglucose F 18 to assess metabolic activity of a pelvic mass in 18 patients who had suspected recurrent rectal cancer. Computed tomography could not differentiate tumor from scar. All patients presenting increased uptake of fludeoxyglucose F 18 by the mass were proved by histologic studies to suffer from recurrent tumor. Six of seven patients with low fludeoxyglucose uptake had nonmalignant lesions. Using immunoscintigraphy in 14 patients with elevated carcinoembryonic antigen levels, only four of ten recurrences could be identified by increased antibody accumulation in the mass. On the other hand, two of four benign lesions were interpreted as being recurrent tumor because of high uptake. Therefore, only positron emission tomography seems to be a useful diagnostic tool in the differentiation of recurrent rectal cancer and scar by providing information about the metabolic activity of a mass.

Antibodies, Monoclonal↗
PubMed1989

[Does immunoscintigraphy improve early diagnosis of metastatic or recurrent cancer?].

In 42 patients with suspicion of recurrent colorectal cancer results of conventional diagnostic methods were compared to those of immunoscintigraphy. In 69% of all cases the intraoperative findings of a second-look operation served for validation, in 31% the follow-up was controlled. Localization of recurrent tumors was successful in 83% using conventional methods versus 57% by immunoscintigraphy. This procedure disappointed especially by a low sensitivity (23%) and low predictive parameters (pos.: 33%; neg.: 37%) in regard to diagnosis of extrahepatic tumors compared to results of conventional methods (77%), 94% respectively 79%). The quote of false positive results was surprisingly high in immunoscintigraphy (n = 12), 83% of these especially in localization of extrahepatic tumors. Therefore, the validity of immunoscintigraphy as an additive diagnostic tool for early detection of recurrent colorectal cancer must be regarded critically.

Antibodies, Monoclonal↗
PubMed1989

[Radiologic diagnosis of bone metastases].

The diagnostic relevance of the various radiological examination methods - skeleton scintigraphy, conventional x-ray film, computed tomography, sonography and magnetic resonance - was analysed on the basis of an examination of 4765 clinically or scintigraphically suspect skeleton segments in order to arrive at an effective but also economically justifiable diagnostic approach. Conventional skeleton scintigraphy should be employed as the first method of choice, since it has a sensitivity of 93% and is hence very suitable as a searching tool. To differentiate benign and malignant lesions it is absolutely imperative to conduct at the same time a x-ray control of any abnormal accumulation of nuclides, or of parts of the skeleton that display signs or symptoms. Conventional x-ray film diagnosis enabled correct diagnosis of the type of disease in 95% of the cases. In its capacity as a complementary examination method, computed tomography enabled correct diagnosis in 52% of the cases that had remained roentgenologically unclear. A pathological bone scintigram without any x-ray or CT correlate must be considered as being suspect of metastases if trauma is absent. Magnetic resonance proved to be the most sensitive method in identifying malignant infiltrations of the medullary space in two patients suffering from a clearly delineated pain syndrome with normal x-ray and CT findings. Sonography proved superior in detecting extraosseous tumour portions. The value of angiography is the preoperative vascular imaging of metastases of the possibility of performing therapeutic embolisation or intraarterial drug therapy.

Angiography↗
PubMed1989

[Effects of gallopamil on iodine-123-phenyl-pentadecanoic acid and thallium 201 uptake in patients with coronary heart disease].

Numerous experimental and clinical studies indicated that in the presence of coronary artery stenoses, myocardial thallium-201 and free fatty acid uptake in poststenotic regions is reduced during exercise. The aim of this study was to investigate the effect of the calcium antagonist gallopamil on myocardial thallium-201 and free fatty acid uptake in patients suffering from coronary artery disease. In 6 patients with angiographically proven coronary artery disease--2 patients with 1-vessel, 2 patients with 2-vessel and 2 patients with 3-vessel disease--as well as good left ventricular performance and stable, exerciseinduced angina, quantitative double-tracer scintigraphy was performed. Patients were investigated after a placebo period of 1 week, after oral gallopamil medication for 4 weeks (3 X 50 mg gallopamil daily), and after a double-blind period of 1 week. During symptom-limited exercise, 2 mCi thallium-201 and 5 mCi iodine-123 phenyl-pentadecanoic acid (IPPA) were simultaneously injected intravenously. Immediately after exercise, as well as 1 and 4 hours later, planar images were obtained in ap, 30 degrees LAO and 60 degrees LAO projections. By means of a newly developed computer algorithm, global and regional myocardial tracer uptake as well as IPPA clearance were evaluated. - Gallopamil provoked a decrease of global myocardial thallium-201 and IPPA uptake due to a reduction of myocardial oxygen consumption. Regional thallium-201 and IPPA uptake as well as myocardial IPPA clearance in poststenotic areas tended to rise following gallopamil medication. Thus, in the presence of coronary artery disease, gallopamil provokes an improvement of regional perfusion (dilatation of larger coronary arterioles) as well as an enhanced free fatty acid utilization in reversibly ischemic myocardial regions.

Angina Pectoris↗
PubMed1989

[Preliminary results of 99mTc-HMPAO-SPECT studies in endogenous psychoses].

18 psychopharmacologically treated patients (7 schizophrenics, 5 schizoaffectives, 6 depressives) were studied using 99mTc-HMPAO-SPECT of the brain. The regional cerebral blood flow was measured in three transversal sections (infra-/supraventricular, ventricular) within 6 regions of interest (ROI) respectively (one frontal, one parietal and one occipital in each hemisphere). Corresponding ROIs of the same section in each hemisphere were compared. In the schizophrenics there was a significantly reduced perfusion in the left frontal region of the infraventricular and ventricular section (p less than 0.02) compared with the data of the depressives. The schizoaffectives took an intermediate place. Since the patients were treated with psychopharmaca, the result must be interpreted cautiously. However, our findings seem to be in accordance with post-mortem-, CT- and PET-studies presented in the literature. Our results suggest that 99mTc-HMPAO-SPECT may be helpful in finding cerebral abnormalities in endogenous psychoses.

Adult↗
PubMed1989

[Diagnosis and therapy of differentiated thyroid cancer].

Summing up, we can state the following: Diagnosis of thyroid cancer seems easy, since the organ lies immediately beneath the skin, so that tumour growth could be readily detected, and also since thyroglobulin (tg) is an ideal and well-tried tumour marker. Nevertheless, malignant thyroid nodes are still frequently misinterpreted as benign, as benign strumae occur quite often. In view of the fact that malignant follicular carcinomas have a tendency to produce metastases via the bloodstream, in all tumours larger than 1 cm to 1.5 cm no change should be made in the classical therapeutic approach (total thyroidectomy, radioiodine therapy and levothyroxine suppression therapy), whereas in so-called occult papillary thyroid cancer (i.e. carcinomas smaller than 1-1.5 cm) hemithyroidectomy and lifelong suppression therapy can be satisfactory. It follows from this that in view of the low complication rate even with maximal therapy of differentiated thyroid cancer and the advantages resulting therefrom for follow-up care, the total ablation therapy should be retained as standard treatment. The low incidence of thyroid cancer justifies, inter alia, central follow-up care, the more so since this is usually performed on an interdisciplinary basis and there is as yet no standardised procedure for thyroglobulin determination.

Adenocarcinoma↗