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H Y Oei

Publications and source records attributed to H Y Oei.

At least 37 records · Page 2Linked to original sources
PubMed1994

Somatostatin receptor scintigraphy: its value in tumor localization in patients with Cushing's syndrome caused by ectopic corticotropin or corticotropin-releasing hormone secretion.

PURPOSE: To assess the feasibility of somatostatin receptor scintigraphy for patients with Cushing's syndrome caused by tumors secreting ectopic corticotropin or corticotropin-releasing hormone (CRH). PATIENTS AND METHODS: Ten patients with Cushing's syndrome, nine with ectopic corticotropin-secreting tumors and one with a CRH-secreting tumor, were consecutively studied. For comparison purposes, eight patients with corticotropin-secreting pituitary tumors and one patient with an autonomous adrenal adenoma were investigated. In vivo tumor localization was performed for all patients using a radionuclide-coupled somatostatin analog. The results obtained with this technique were compared with those obtained with conventional imaging techniques. For some patients, the clinical effects of octreotide therapy were evaluated. RESULTS: Somatostatin analog scintigraphy successfully identified the primary ectopic corticotropin-secreting and CRH-secreting tumors or their metastases, or both, in 8 of 10 patients; in 2 patients with corticotropin-secreting bronchial carcinoids, the tumors could not be visualized. Normal scans were obtained for the 8 patients with corticotropin-secreting pituitary tumors and the one patient with an adrenal adenoma. CONCLUSION: Somatostatin analog scintigraphy can be included as a diagnostic step in the workup of Cushing's syndrome patients with a suspected ectopic corticotropin-secreting tumor or a CRH-secreting tumor.

ACTH Syndrome, Ectopic↗
PubMed1994

Somatostatin receptor scintigraphy in carcinoids, gastrinomas and Cushing's syndrome.

High numbers of high-affinity somatostatin binding sites have been found on carcinoid tumors, gastrinomas, small cell lung cancers and the majority of medullary thyroid cancers, enabling in vivo visualization of these tumors with octreotide scintigraphy. A comparison of the results obtained at our institution and another 15 centers in Europe show a few remarkable similarities and differences. The overall sensitivity of octreotide receptor scintigraphy to detect the primary GEP tumor and its metastases is high, e.g. 80-90%. The main difference was found in gastrinomas and to a lesser extent in insulinomas. These differences might be attributed to different scanning protocols. Furthermore, octreotide scintigraphy also has a high sensitivity to localize the primary tumor and its metastases causing Cushing's syndrome by ectopic production of ACTH or CRH. Octreotide scintigraphy is a new, sensitive and noninvasive technique to localize somatostatin receptor expressing endocrine tumors and their metastases.

Carcinoid Tumor↗
PubMed1994

[111In-DTPA-D-Phe1] octreotide scintigraphy in thyroidal and orbital Graves' disease: a parameter for disease activity?

Visualization of malignant lymphomas and granulomatous disease is possible by [111In-DTPA-D-Phe1]octreotide scintigraphy through binding of the radioligand to somatostatin receptors on activated leukocytes. Because thyroidal and orbital tissues are infiltrated by activated leukocytes in Graves' disease, a cross-sectional study to visualize disease activity with [111In-DTPA-D-Phe1]octreotide scintigraphy was performed. A correlation between thyroidal [111In-DTPA-D-Phe1]octreotide accumulation and free T4 (disease expression) and thyroid binding-inhibiting immunoglobulins (disease activity) is present in untreated hyperthyroid Graves' disease. There is also a correlation between orbital [111In-DTPA-D-Phe1]octreotide uptake and the clinical activity score (disease activity) and total eye score (disease expression), respectively, in Graves' orbitopathy. Visualization of thyroidal and orbital Graves' disease is feasible, but further investigation is necessary to establish the role of [111In-DTPA-D-Phe1]octreotide scintigraphy in representing disease activity and expression and in predicting therapeutical outcome.

Eye↗
PubMed1993

Somatostatin analogue scintigraphy in carcinoid tumours.

Scintigraphy with iodine-123 or indium-111 labelled somatostatin analogue (octreotide) was performed in 52 patients diagnosed as, suspected of, or at risk of having carcinoid tumours. In 32 of 37 (86%) patients in whom histologically proven carcinoids were still present, known tumour sites were visualized. Using 123I-coupled octreotide, 24 of 40 (60%) known extrahepatic sites were visualized, whereas all of 12 (100%) extrahepatic lesions were visualized after injection of 111In-coupled octreotide. Known liver metastases were not distinctly visualized with octreotide scintigraphy in 12 of 24 patients. In all but two of these cases, an even distribution of radioactivity in the liver was observed. This is most probably due to the fact that these liver metastases accumulated about as much radioactivity as does normal liver tissue. Previously unsuspected localizations or sites not recognized with other imaging techniques were found in 20 of the 37 patients. In 3 of 11 patients who were thought to have been surgically cured, and in 4 of 4 patients who were suspected of having carcinoids, octreotide scintigraphy showed abnormal accumulation of radioactivity. Histological or radiological evidence that additional sites noticed on octreotide scintigrams indeed represented tumour tissue was obtained in ten patients. Visualization of the carcinoids did not depend on the site of the tumour or on the presence or absence of hormonal hypersecretion, as measured by urinary 5-hydroxyindoleacetic acid and serum alpha-subunit concentrations. Apart from its use for tumour localization, octreotide scintigraphy, in consequence of its ability to demonstrate somatostatin receptor positive tumours, could be used to select those patients with the carcinoid syndrome who are likely to respond favourably to octreotide treatment.

Adult↗
PubMed1993

Captopril radionuclide test in renovascular hypertension: a European multicentre study. European Multicentre Study Group.

The diagnostic work-up of renovascular hypertension is still controversial. The efficacy of renal scintigraphy with technetium-99m diethylene triamine pentaacetate (DTPA) before and after captopril (scintigraphic captopril test) was evaluated in a multicentre study. All 380 hypertensive patients in the study underwent renal arteriography; 125 had renal arterial stenosis > or = 70%, and 54 had a technically successful intervention to correct the stenosis. The post-captopril study had a sensitivity of 93% and a specificity of 100% for predicting blood pressure response to intervention, if renal function was normal and a combination of quantitative parameters was applied (individual kidney uptake index < 40%, time to peak activity < 2 min or > 10 min). In the entire population renal artery stenosis > or = 70% was detected with a sensitivity of 83% and a specificity of 93% if renal function was normal. In patients with abnormal renal function the performance of the test was worse, owing to a lower specificity which could be increased by using only time parameters. The performance of the test was optimal when the post-captopril findings were examined; no improvement was achieved by evaluation of the changes induced by captopril from the baseline. The test can thus be simplified by performing only a post-captopril study for routine use: a negative test would exclude a curable form of renovascular hypertension in > 80% and a positive test would predict it in > 90% of the patients selected for suspicion of the disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Somatostatin receptor scintigraphy with [111In-DTPA-D-Phe1]- and [123I-Tyr3]-octreotide: the Rotterdam experience with more than 1000 patients.

Various tumours, classically specified as either neuroendocrine or non-neuroendocrine, contain high numbers of somatostatin receptors, which enable in vivo localization of the primary tumour and its metastases by scintigraphy with the radiolabelled somatostatin analogue octreotide. In addition granulomas and autoimmune processes can be visualized because of local accumulation of somatostatin receptor-positive activated mononuclear leucocytes. In many instances a positive scintigram predicts a favourable response to treatment with octreotide. It is tempting to speculate that octreotide labelled with an appropriate radionuclide might be used in cancer therapy. The successful application of radiolabelled octreotide in scintigraphy indicates the possible usefulness of other radiolabelled peptides, either native peptides or derivatives of these, in, for example, nuclear oncology. The small size of these peptides, e.g. bombesin and substance P, is of the utmost importance for a relatively fast blood clearance, thus leading to low background radioactivity. In this way peptides are powerful alternatives to (fragments of) monoclonal antibodies, the application of which to scintigraphic localization of specific cell surface antigen-bearing tumours is plagued by slow blood clearance and, hence, high background levels.

Humans↗
PubMed1993

Somatostatin analogue scintigraphy of malignant lymphomas.

Normal as well as activated lymphocytes, macrophages and leukaemic cells have previously been shown by radio receptor analysis to express receptors for somatostatin. An 111In labelled somatostatin analogue was already used successfully in the visualization of a variety of neuro-endocrine tumours. We investigated 10 consecutive patients with malignant lymphomas (Hodgkin's disease and non-Hodgkin's lymphomas). In all patients the lymphoma deposits could be visualized with somatostatin receptor imaging. In four patients additional tumour localizations were observed as compared to the results of combined physical and radiological (CT and ultrasound) examinations. In four cases tissue biopsies were taken and confirmed by autoradiography to be somatostatin receptor positive. These data indicate that malignant lymphomas may express somatostatin receptors in sufficient numbers and density to allow in vivo tumour visualization with a radiolabelled somatostatin analogue.

Hodgkin Disease↗
PubMed1993

111In-octreotide scintigraphy in oncology.

Various tumors of neuroendocrine origin that have amine precursor and decarboxylation (APUD) characteristics can be visualized in vivo after intravenous injection of the somatostatin analogue [123I-Tyr3]-octreotide. However, the relatively short effective half-life of this compound and the high background of radioactivity in the abdomen are drawbacks in its application. Therefore, an 111In-coupled somatostatin analogue ([111In-DTPA-D-Phe1]-octreotide) was developed. This analogue is excreted mainly via the kidneys, 90% of the dose being present in the urine 24 h after injection. Using 111In-octreotide scintigraphy, 7 out of 7 gastrinomas, 4 out of 7 insulinomas, 1 out of 1 glucagonoma, 3 out of 3 unclassified apudomas, but none out of 18 exocrine pancreatic carcinomas were visualized. Also, 19 out of 19 carcinoids, 15 out of 15 glomus tumors, 8 out of 12 medullary thyroid carcinomas, 6 out of 6 small cell lung carcinomas, 4 out of 4 growth hormone-producing and 6 out of 9 clinically nonfunctioning pituitary adenomas were visualized. Apart from APUD-cell-derived tumors, 111In-octreotide scintigraphy was also successfully applied to visualize breast cancer, lymphomas and granulomas. In 39 out of 50 patients with breast carcinoma, 10 out of 11 patients with non-Hodgkin lymphomas, 3 out of 3 patients with Hodgkin's disease, and 8 out of 8 patients with sarcoidosis, tumor sites accumulated radioactivity during octreotide scintigraphy. In a considerable number of patients with carcinoids and glomus tumors, but also in patients with granulomas and lymphomas, 111In-octreotide scintigraphy revealed more tumor sites than did conventional imaging techniques.(ABSTRACT TRUNCATED AT 250 WORDS)

Apudoma↗
PubMed1993

In vivo somatostatin receptor imaging in medullary thyroid carcinoma.

Using in vivo scintigraphy with the 111In-labeled somatostatin analog octreotide, tumor localizations were demonstrated in 11 of 17 patients (65%) with medullary thyroid carcinoma (MTC). Tumor localizations in the liver in 7 patients, and in the thyroid in 1 patient were not detected on octreotide scintigraphy, most probably because of normal uptake of labeled octreotide in these organs. Specific somatostatin receptors were demonstrated in vitro on all 5 investigated tumors which had also been visualized in vivo, as well as on 1 tumor that was not. Immunohistochemically, somatostatin was present in 1 of 6 tumors that were visualized in vivo, and in neither of 2 tumors that were not. The ratio of serum calcitonin over carcino-embryonic antigen concentrations was significantly higher in patients whose MTCs were visualized during octreotide scintigraphy than in those whose tumors were not. We have formed the following conclusions: 1) In the majority of patients with metastatic MTC, tumor sites can be visualized using octreotide scintigraphy, although this technique is insensitive in detecting liver metastases or intrathyroidal tumor; 2) The visualization of MTC during in vivo somatostatin receptor imaging correlates with the in vitro presence of somatostatin receptors; 3) The immunohistochemical presence of somatostatin in the tumor does not seem to influence the outcome of in vivo somatostatin receptor imaging; and 4) Higher serum calcitonin over carcino-embryonic antigen ratios in patients whose MTC is visualized during octreotide scintigraphy might imply that somatostatin receptors are present on more differentiated MTC.

Adult↗
PubMed1992

Somatostatin receptor imaging of endocrine gastrointestinal tumors.

UNLABELLED: Somatostatin receptors are present on various tumors of neuroendocrine origin. We recently developed a technique for the in vivo visualization of somatostatin receptor positive tumors, which offers a powerful alternative to tumor imaging with labeled monoclonal antibodies. Instead of injecting radiolabeled antibodies against the somatostatin receptor, we labeled a somatostatin analogue ([Tyr3]-octreotide) which is known to bind specifically to the somatostatin receptor, and injected this labeled hormone analogue in order to visualize somatostatin receptor positive tumors. We previously reported the successful visualization of the primary tumors or metastases of various endocrine gastrointestinal tumors after injection of the iodinated somatostatin analogue [123I-Tyr3]-octreotide. The primary tumors or metastases of 12 out of 13 carcinoids, 3 out of 3 gastrinomas, 2 out of 4 insulinomas, and 1 out of 1 somatostatinoma were visualized. Using 111In-coupled octreotide, we were able to visualize 19 out of 19 carcinoids, 7 out of 7 gastrinomas, 4 out of 7 insulinomas, 1 out of 1 glucagonoma, and 3 out of 3 non-functioning endocrine pancreatic tumors, but none of 18 exocrine pancreatic tumors. In a large proportion of patients with endocrine gastrointestinal tumors, previously unrecognized metastases were demonstrated. Also, the absence or presence of in vivo visualization of these tumors after the injection of radiolabeled octreotide seems to predict the ability of octreotide therapy to control symptoms caused by hormonal secretion from these tumors. IN CONCLUSION: 111In-octreotide scintigraphy is a simple and sensitive technique for localizing of the primary tumor and its metastases in the majority of patients with carcinoids or endocrine pancreatic tumors.(ABSTRACT TRUNCATED AT 250 WORDS)

Endocrine Gland Neoplasms↗
PubMed1992

Somatostatin analogue scintigraphy. A simple and sensitive method for the in vivo visualization of Merkel cell tumors and their metastases.

BACKGROUND: Trabecular carcinomas of the skin, or Merkel cell tumors, are aggressive neoplasms that tend to occur in sun-exposed skin. These tumors frequently metastasize and, despite therapy, the number of disease-related deaths is high. Ultrastructurally and immunocytochemically, the majority of these tumors have neuroendocrine characteristics. Recently, we described the in vivo visualization of various neuroendocrine tumors after injection of a radiolabeled somatostatin analogue (octreotide). In this study, we report the results of scintigraphy with radioactive-labeled somatostatin analogues in five patients with Merkel cell tumors. OBSERVATIONS: In all four patients in whom tumor was detected using computed tomographic scanning and ultrasound, the tumor sites were also demonstrated on octreotide scintigrams. In one patient, a tumor with a diameter that was smaller than 0.5 cm could not be detected with octreotide scintigraphy, computed tomography, or ultrasound. Using octreotide scintigraphy we found presumed tumor spots in two patients that were not evident when other techniques were used. CONCLUSIONS: Octreotide scintigraphy has an equal or even greater sensitivity than computed tomography and ultrasound for detecting Merkel cell tumors and their metastases. Establishing the spread of the disease in this way may ensure an optimal choice of treatment in patients with this type of tumor.

Aged↗
PubMed1992

111In-octreotide scintigraphy in oncology.

Various tumors of neuroendocrine origin that have amine precursor uptake and decarboxylation (APUD) characteristics can be visualized in vivo after intravenous (IV) injection of the somatostatin analogue, [123I-Tyr3]-octreotide. However, the relatively short effective half-life of this compound and the high background of radioactivity in the abdomen are drawbacks to its application. Therefore, an 111In-coupled somatostatin analogue ([111In-DTPA-D-Phe1]- octreotide) was developed. This analogue is excreted mainly via the kidneys, with 90% of the dose being present in the urine 24 hours after injection. Using 111In-octreotide scintigraphy, seven of seven gastrinomas, four of seven insulinomas, one of one glucagonomas, three of three unclassified APUDomas, and none of 18 exocrine pancreatic carcinomas were visualized. Also, 19 of 19 carcinoids, 15 of 15 glomus tumors, eight of 12 medullary thyroid carcinomas, six of six small-cell lung carcinomas, four of four growth hormone-producing and six of nine clinically nonfunctioning pituitary adenomas were visualized. Apart from APUD cell-derived tumors, 111In-octreotide scintigraphy was also successfully applied in visualizing breast cancer, lymphomas, and granulomas. In 39 of 50 patients with breast carcinoma, 10 of 11 patients with non-Hodgkin's lymphomas, three of three patients with Hodgkin's disease, and eight of eight patients with sarcoidosis, tumor sites accumulated radioactivity during octreotide scintigraphy. In a considerable number of patients with carcinoids and glomus tumors, and also in patients with granulomas and lymphomas, 111In-octreotide scintigraphy showed more tumor sites than did conventional imaging techniques. The results of imaging in vivo correlated with the somatostatin-receptor status on the tumors in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)

Acromegaly↗
PubMed1992

Somatostatin receptor scintigraphy with indium-111-DTPA-D-Phe-1-octreotide in man: metabolism, dosimetry and comparison with iodine-123-Tyr-3-octreotide.

Scintigraphy with 123I-Tyr-3-octreotide has several major drawbacks as regards its metabolic behavior, its cumbersome preparation and the short physical half-life of the radionuclide. The use of another radiolabeled analog of somatostatin, 111In-DTPA-D-Phe-1-octreotide, has consequently been proposed. DTPA-D-Phe-1-octreotide can be radiolabeled with 111In in an easy single-step procedure. DTPA-D-Phe-1-octreotide is cleared predominantly via the kidneys. Fecal excretion of radioactivity amounts to only a few percent of the administered radioactivity. For the radiation dose to normal tissues, the most important organs are the kidneys, the spleen, the urinary bladder, the liver and the remainder of the body. The calculated effective dose equivalent is 0.08 mSv/MBq. Optimal 111In-DTPA-D-Phe-1-octreotide scintigraphic imaging of various somatostatin receptor-positive tumors was obtained 24 hr after injection. In the six patients studied, tumor localization with 123I-Tyr-3-octreotide and with 111In-DTPA-D-Phe-1-octreotide were found to be similar. However, the normal pituitary is more frequently visualized with the latter radiopharmaceutical. In conclusion, 111In-DTPA-D-Phe-1-octreotide appears to be a sensitive somatostatin receptor-positive tissue-seeking radiopharmaceutical with some remarkable advantages: easy preparation, general availability, appropriate half-life and absence of major interference in the upper abdominal region, because of its renal clearance. Therefore, 111In-DTPA-D-Phe-1-octreotide may be suitable for use in SPECT of the abdomen, which is important in the localization of small endocrine gastroenteropancreatic tumors.

Adult↗
PubMed1991

Captopril renography. Early observations and diagnostic criteria.

This article describes the methods and the interpretation of captopril renography. The essentials of the methods are the discontinuation of diuretics, the refraining from solid foods before administration of 25 mg captopril, hydration to induce diuresis, the performing of 1-min sequential images, data acquisition with frame time not exceeding 30 sec, and the calculation of the left to right ratio. In most instances data from captopril renography can be interpreted without the presence of a baseline study. Abnormalities of the sequential images and the renal curves classified as grade 2 and 3 indicate the presence of renal artery stenosis. Besides, in unilateral stenosis, captopril induced renographic abnormality can also be observed in bilateral and segmental stenosis. Interpretation based on numeric parameters probably does not increase the sensitivity. Alterations on mercaptoacetyltriglycine (MAG3) studies are identical to the alterations observed on orthoiodohippurate (OIH) studies. In severe stenosis, alterations in diethylene-triaminepentaacetic acid studies are different from those observed in OIH or MAG3 studies. Since MAG3 provides the best images, at present MAG3 is the radiopharmaceutical of choice.

Adolescent↗
PubMed1991

Radioiodinated somatostatin analog scintigraphy in small-cell lung cancer.

Somatostatin receptors have been characterized on biopsy specimens from small-cell lung carcinoma (SCLC) and on cultured human SCLC cells. We recently described the in vivo visualization of various somatostatin receptor-positive tumors, such as carcinoids and endocrine pancreatic tumors, after injection of 123I-Tyr-3-octreotide, a radiolabeled somatostatin analog. In the present study, this imaging procedure using 123I-Tyr-3-octreotide is reported in 11 patients with lung tumors. In five of eight patients with SCLC (63%), we were able to demonstrate tumor deposits using 123I-Tyr-3-octreotide scintigraphy. Unexpected metastases were found in two patients. In one of three patients with SCLC in whom tumor was not visualized, nonvisualization may have been caused by tumor necrosis and recent radiotherapy. In one of two patients with malignant small-cell tumors as described by Askin, the neoplasm was visualized. Like SCLC, these tumors are thought to derive from neuroendocrine cells. In one patient, a squamous-cell carcinoma and a bronchial adenoma were not visualized. We conclude that in the majority of patients with SCLC, the tumor and its metastases can be visualized using 123I-Tyr-3-octreotide scintigraphy. However, the value of this new technique in terms of specificity and sensitivity requires further studies in a larger group of patients.

Adolescent↗
PubMed1988

Renovascular hypertension: the small kidney updated.

We report the results of treatment in 57 patients with renovascular hypertension associated with one poorly perfused, small kidney with less than 25 per cent of total 131I-hippurate uptake shown by renography. Arteriography in 29 patients demonstrated occlusion of the artery of the small kidney, and in 28 there was stenosis. In addition, 25 patients had stenosis of the artery supplying the larger contralateral kidney. Stenosis of the arteries of the contralateral kidneys was dilated by percutaneous transluminal arterioplasty in all but one of the 25 patients with bilateral disease of the artery, stenosis of the small kidney could be dilated successfully by percutaneous transluminal arterioplasty in 22 of the 28 patients, and cure or improvement of blood pressure was achieved in 12 of them. Percutaneous transluminal arterioplasty of occluded arteries was generally unsuccessful. In 17 patients with unilateral disease not manageable by percutaneous transluminal arterioplasty, nephrectomy of the small kidney improved blood pressure control without significant deterioration of renal function. Renal function improved in 10 patients with bilateral lesions treated by nephrectomy of the small kidney in combination with contralateral percutaneous transluminal arterioplasty. Histological examination of excised kidneys showed large infarcts or several cholesterol emboli whether percutaneous transluminal arterioplasty had been attempted or not. After observation periods ranging from two to 79 months, 48 patients were normotensive (21 without and 27 with medication) and nine patients were still hypertensive even with medication. This study showed that by using percutaneous transluminal arterioplasty initially if possible, supplemented with nephrectomy and/or medication, normotension without loss of renal function or immediate serious complications could be obtained in the majority of these severely hypertensive patients.

Adult↗