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Biomedical subjects

P Georgi

Publications and source records attributed to P Georgi.

At least 55 records · Page 3Linked to original sources
PubMed1987

[Uptake behavior of bone metastases of hypernephroma in the 99m Tc-MDP bone scintigram. A comparison with x-ray findings].

Ninety-one radiologically confirmed osteolytic metastases in 30 patients with hypernephromas were studied with regard to their uptake of 99mTc-MDP and this was compared with the radiological findings. In 16% of the radiologically proven metastases, there was no correlation with their isotope uptake. Compared with other bone metastases whose isotope uptake has been studied and described in the literature, there appears to be a higher proportion of hypernephroma secondaries that do not show uptake of 99mTc-MDP.

Adult↗
PubMed1987

[Value of 3-phase skeletal scintigraphy in the diagnosis of bone metastases].

51 patients suffering from 125 bone metastases of various primary tumors were investigated with three-phase skeletal scintigraphy in an attempt to define criteria characteristic for bone metastases with regard to differential diagnosis. During the 3 phases of imaging, the metastases exhibited 5 different patterns of activity concentration. None of these patterns was correlated either to the size and morphological X-ray appearance of the metastases or to the histology of the primary tumors. The intensity of radionuclide concentration was also varying. The most frequent patterns of activity concentration were increased uptake during the blood-pool phase and skeletal phase combined with absence of concentration during the angiographical phase (43%), and increased uptake during all of the 3 phases (34%). In this series, a pattern of scintigraphical findings characteristic for bone metastases or helpful in the differential diagnosis could not be determined. In our experience, three-phase skeletal scintigraphy is not useful in the diagnosis and differential diagnosis of bone metastases.

Bone Neoplasms↗
PubMed1987

Carcinoid tumors: CT and I-131 meta-iodo-benzylguanidine scintigraphy.

The diagnostic value of computed tomography (CT) and iodine-131 meta-iodo-benzylguanidine (MIBG) scintiscanning was studied in nine patients with histologically proved carcinoid tumors of intestinal (n = 4), bronchial (n = 3), or thymic (n = 2) origin. CT scans clearly depicted the tumors and metastases in relation to surrounding vital structures but did not provide findings specific for carcinoids. The appearance on CT of an abdominal soft-tissue mass with a radiating pattern of linear densities was found to be highly suggestive of intestinal carcinoid tumors. I-131 MIBG scintiscans disclosed intense tracer uptake in the tumors and metastases in five patients. MIBG studies correctly depicted nine of nine tumor manifestations in intestinal carcinoids and four of six tumor manifestations in bronchus carcinoids. No MIBG concentration was found in thymus carcinoids. Because of its selective uptake mechanism, I-131 MIBG scintigraphy can allow specific detection and localization of neuroendocrine tumor tissue in patients with suspected carcinoid tumors. MIBG scintigraphy has diagnostic potential as a screening procedure in carcinoid tumors, especially those of intestinal origin.

3-Iodobenzylguanidine↗
PubMed1987

[Current role of immunoscintigraphy for surgical therapy of the recurrence of colorectal cancers].

In patients with local recurrence or liver metastases from colorectal cancer the preoperative results of conventional diagnostic methods (sonography, computed tomography, x-ray, endoscopy) and immunoscintigraphy performed with 131I labeled CEA/Ca 19-9 antibodies were compared to intraoperative findings. Specificity of immunoscintigraphy in detecting liver metastases was higher compared to conventional diagnostic methods but its predictive reliability was disappointing, especially in regard to diagnosis of the number of liver metastases and detection of local recurrence or peritoneal seedings. Compared to all intraoperative findings a positive predictive value of 74% and a negative predictive value of 42% for immunoscintigraphy could be found as compared to 88% and 63%, respectively, for conventional diagnostic methods. So immunoscintigraphy in our experience cannot give more information beyond conventional diagnostic tools for indication or planning of operative strategy in the treatment of recurrent colorectal cancer.

Adenocarcinoma↗
PubMed1986

[Bone marrow scintigraphy using radiocolloids in bone metastases. Sensitivity, specificity, reliability and indications].

The sensitivity and specificity of bone marrow scintigraphy in demonstrating skeletal metastases was examined in 40 patients with focal metastases. Radiology and MDP scintigraphy were used as reference methods. Sensitivity depends on the region of the skeleton. False negatives are the rule in parts of the skeleton containing little bone marrow. In relation to the entire bone marrow content, sensitivity is 0.64. The high proportion of false negatives (36%) in the presence of confirmed metastases and the incomplete demonstration of the bone marrow makes marrow scintigraphy unsuitable as a screening method. Occasionally lesions confined to the marrow can be demonstrated when radiographs and bone scintigrams are still negative. In advanced cases, marrow scintigraphy can demonstrate the extent of destruction of the bone marrow. Demonstration of displacement or of an 'empty bone' is evidence of invasion of the bone marrow in patients with tumours. In patients with reduced haematopoiesis of unknown origin or unidentified diffuse skeletal uptake, bone marrow scintigraphy may provide valuable information.

Adult↗
PubMed1986

[Malignant pleural mesothelioma. Value of 67Ga scintigraphy compared to computerized tomography].

In 34 patients with suspected malignant pleural mesothelioma the results of computed tomography are compared with the findings of 67Ga-scintigraphy. The differential diagnosis of 14 pleural mesotheliomas, 7 pleural carcinoses, 10 inflammatory and 3 other pleural diseases is performed more accurately by CT than by scintigraphy. 67Ga uptake depends on the thickness of inflammatory as well as malignant lesions. Thus, numerous pleural processes that can be localised by CT escape scintigraphic detection. CT is indicated if there is clinical and radiological suspicion of pleural mesothelioma; in that case, there is hardly any indication for 67Ga scintigraphy.

Adult↗
PubMed1986

[Value of scintigraphy with 111In-acetylacetone-labelled auto-leukocytes in the diagnosis of infected total endoprostheses].

Scintigraphy with 111In-acetylacetone-leucocytes is valuable in detecting infectious processes in alloarthroplasties of the hip and knee. The sensitivity of 95% is high whereas the specificity of 74% is low due to the high incidence of falsely positive results. These are seen mainly in aggressive granulomas of the hip caused by alloarthroplasties using metal sockets and polyethylene heads. Since those alloarthroplasties are no longer used the incidence of falsely positive scans will decrease and the specificity of the method is likely to increase.

Bacterial Infections↗
PubMed1986

[Indium-111 scintigraphy in acute and chronic osteomyelitis in animal model. An experimental study].

Studies on 28 New Zealand white rabbits with experimentally induced osteomyelitis show that 111In-leukocyte scans turn negative when inflammation changes from the acute stage (histologically represented mainly by granulocytes and only small development of collagenous fibres) into the chronic stage (histologically showing marked lymphoplasmacytic infiltration and increased development of connective tissue). Falsely negative scans (i.e. cold lesions) are due to marked medullar necroses accompanied by diminished development of an abscess wall and reduced concentration of granulocytes within the necroses. Truly negative scans (i.e. cold lesions) are seen in chronic osteomyelitis with extended medullar fibrosis accompanied by reduced blood flow in comparison to the normal medullar bone of the contralateral side. The histological course of experimental osteomyelitis in rabbits is in some respect comparable with the stages of osteomyelitis in man and allows to predict the result of the leukocyte scan.

Animals↗
PubMed1985

[Scintigraphic imaging of benign and malignant tumors of the sympathetic nervous system with meta-iodobenzylguanidine].

The authors report on their experiences with metaiodine-benzylguanidine (MIBG) scintiscanning in a total of 36 patients. 7 of these patients had a benign pheochromocytoma, 4 a malignant one; neuroblastoma was seen in 10 patients. Scintiscan diagnosis was supplemented by measurements of irradiation exposure and attainable tumour dose. It was also shown that it is possible to mark neuroblastoma cells in cultures. The results of these studies are discussed and compared with those of other working groups. If the physiological pattern of distribution is taken into consideration, and if the proper imaging technique is adopted, MIBG scintiscan is a sensitive and highly specific method in diagnosing pheochromocytomas and neuroblastomas.

3-Iodobenzylguanidine↗
PubMed1985

[Leukocyte scintigraphy of inflammatory processes in the spinal column].

Scintigraphic studies with labelled leucocytes in 30 patients with suspected inflammatory processes in the spinal column showed false negative results in all cases, even in acute inflammatory lesions. This is in contrast to the good results in detecting inflammatory bone processes in the non-axial parts of the skeleton, where an accuracy of 88% was found. These findings demonstrate that scintigraphy with labelled leucocytes is not suitable for diagnosing bacterial inflammatory diseases in the spinal column.

Adult↗
PubMed1984

N-13 L-glutamate uptake in malignancy: its relationship to blood flow.

Studies on glutamate uptake, with special reference to perfusion, were carried out in 35 rats, each bearing one of five different tumor transplants; also in 15 rats after bone fracture, and in three rabbits. Single-pass extraction of N-13 glutamate was 85-93% in the VX2 tumor of the rabbit and in muscle. Bone fracture in rats caused a threefold increase of tracer uptake 2 days after the event. In tumor transplants, the tumor-to-muscle uptake ratio reached a maximum immediately following injection of the tracer. Comparing N-13 glutamate uptake with the retention of 1-121 microspheres, identical tumor-to-muscle ratios were found for three out of five tumor lines. Comparing the uptake with that of C-11 butanol (ten rats), a close correlation was observed throughout the range of tumor lines. The results suggested that glutamate uptake by malignant tumors is related to blood flow. In nine patients with malignant or benign lesions tumor-to-muscle uptake of N-13 glutamate and TI-201 showed a linear correlation close to identity.

Adolescent↗
PubMed1982

Radioisotope therapy of cystic craniopharyngomas.

Eighteen patients suffering from cystic craniopharyngeoma were treated with intracavitary irradiation. The beta-emitting radioisotope 90y (2.25 MeV) was instilled into the cyst following stereotactic puncture of the space-occupying lesion. The surgical approach was planned using angiograms and reconstructed transmission computer tomography (TCT) coronal and saggital sections. Therapy was devised to deliver 20,000 rad to the cyst's wall. Eleven patients received follow-up TCT examinations after four months. Eight of 11 patients had a significant volume decrease in the craniopharyngeoma cyst. In two patients, the cystic volume remained unchanged; one had progression of disease. It is concluded that the intracavitary treatment of cystic craniopharyngeoma will result in a reduction of the size of the space-occupying lesion.

Adolescent↗
PubMed1982

[The scintigraphic diagnosis of pseudo-arthroses following Harrington's spondylodesis (author's transl)].

The development of pseudo-arthroses is the most common complication following operative treatment of severe scoliosis. Early recognition of this event is important to prevent recurrence of the curvature. The diagnosis is not possible by radiological examination of the rigid spine. Routine reexploration implies a second operation, which is unnecessary in the majority of patients with stable fusion. In an attempt to develop a non-invasive method for the diagnosis of pseudo-arthroses, bone scintigrams were carried out in 29 patients with idiopathic scoliosis twelve months after a Harrington's spondylodesis. In 24 patients (82.8%) a definite conclusion could be drawn, either of stable fusion (65.5%) or pseudo-arthrosis formation (17.3%). No pseudo-arthroses were missed by scintigraphy. These results indicate that bone scintigraphy plays an important role in the post-operative care after Harrington's spondylodesis.

Adolescent↗
PubMed1982

Single-photon emission computed tomography (SPECT) for assessment of hepatic lesions.

Single-photon emission computed tomography (SPECT) and conventional scintigraphy were compared in 130 patients examined to assess hepatic involvement in malignant disease. Transmission computed tomography (TCT) served as the reference method against which SPECT and conventional scintigraphy were compared. The sensitivity of SPECT was calculated for lesions grouped according to diameter as well as location. The Bayesian theorem was used to assess the reliability of both SPECT and conventional scintigraphy. SPECT identified only 52% of lesions with a diameter of 1.5-2.0 cm. It was also shown that the sensitivity of SPECT was lowest for small lesions in the middle third of the liver. A comparison of the final diagnosis demonstrated that SPECT had greater sensitivity, specificity, and accuracy than conventional scans, and is superior at low disease prevalence. At high disease prevalence, SPECT has a lower rate of false negatives. SPECT appears to be the superior imaging modality for evaluation of the liver in malignant disease.

Bayes Theorem↗
PubMed1981

Hypertension associated with massive, bilateral, posture-dependent renal dysfunction.

Hippurate function scintiscans were obtained in prone and standing positions in a group of 76 patients with concurrent hypertension and nephroptosis. TWelve of these patients had massive, bilateral disturbance of intrarenal hippurate transport in the standing position; hippurate transport was normal in the prone position. This pattern was present in only three of 120 normotensive patients with nephroptosis. To investigate the importance of nephroptosis, 87 other hypertensive patients were examined. Eighteen of these patients demonstrated posture-dependent tubular dysfunction, but only four had nephroptosis. The results suggest a direct relationship between bilateral posture-dependent tubular dysfunction and hypertension.

Hippurates↗