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Role of magnetic resonance in the study of benign and malignant pheochromocytomas. Quantitative analysis of the intensity of the resonance signal
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Ruolo della risonanza magnetica nello studio dei feocromocitomi benigni e maligni: analisi quantitativa dell'intensità del segnale di risonanza
No full textIn order to assess the clinical role of Magnetic Resonance (MR) imaging in patients with benign or malignant pheochromocytomas, the MR signal intensity ratios of benign and malignant tumors were evaluated. Eighteen patients (9 men and 9 women, mean age: 37 +/- 8 years) with benign (n = 10) or malignant (n = 8) pheochromocytomas were studied. A total of 27 lesions (12 benign and 15 malignant) were analyzed. In all patients, histology confirmed the disease. MR studies were performed using a 1.5-T superconducting magnet system. Sequences were used to obtain T1-weighted (TR/TE 300/12 ms) and T2-weighted (TR/TE 2000/80 ms) images. On both T1- and T2-weighted MR images, the mean absolute signal intensity values of tumor lesions, of liver, muscle and fat tissues, and of image background were measured to obtain the corresponding signal intensity ratios for each lesion. Our results exhibited no statistically significant differences in both T1 and T2 MR signal intensity ratios between benign and malignant lesions. In conclusion, our results suggest that MR imaging cannot differentiate benign from malignant lesions in patients with pheochromocytom
La scintigrafia con iodio-131 metaiodobenzilguanidina nello studio dei paragangliomi: confronto tra tumori benigni e maligni
No full textIn order to evaluate 131I metaiodobenzylguanidine (MIBG) uptake in patients with benign or malignant paragangliomas, 28 patients (14 men and 14 women, mean age 37 +/- 10 years) with benign (no. = 15; group 1) or malignant (no. = 13; group 2) tumors underwent MIBG scintigraphy. A total of 110 lesions (20 benign and 90 malignant) were studied. In all patients histologic disease confirmation was obtained. MIBG uptake was quantified on 48 hours' images (Kodak NMC-1 films) using a photographic densitometer. The optical densities of tumor and adjacent or contralateral normal tissue were used to calculate the MIBG uptake intensity ratio for each lesion. In group 1, all patients exhibited 1 or 2 lesions with abnormal MIBG uptake. In group 2, all patients had 1 to 28 abnormal foci of MIBG uptake. In the patients with 2 or more lesions, the average MIBG uptake intensity ratio was calculated. MIBG uptake intensity ratio was significantly higher in malignant than in benign paragangliomas (5.2 +/- 2.4 vs 2.9 +/- 1.4, p < 0.01). Since MIBG uptake in paragangliomas reflects the intratumoral concentration of catecholamines, higher MIBG uptake in malignant lesions suggests a greater amount of stored catecholamines in these tumors. In conclusion, 131I MIBG scintigraphy may be useful to distinguish benign from malignant paraganglioma
Role of magnetic resonance in the study of benign and malignant pheochromocytomas. Quantitative analysis of the intensity of the resonance signal
No full text
Iodine-131-metaiodobenzylguanidine scintigraphy in preoperative and postoperative evaluation of paragangliomas: comparison with CT and MRI
No full textIodine-131-metaiodobenzylguanidine scintigraphy in preoperative and postoperative evaluation of paragangliomas: comparison with CT and MRI
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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