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  • 1
    Electronic Resource
    Electronic Resource
    Factor analysis of 81mKr lung ventilation studies (1985)
    Springer
    European journal of nuclear medicine 10 (1985), S. 511-518 
    Details
    ISSN: 1619-7089
    Keywords: 81mKr-ventilation ; Factor analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Factor analysis of dynamic structures (FADS) summarizes data depending on time and space in a few elementary components. Each of them associates a time-activity curve (factor) and the spatial distribution of the corresponding events. The aim was to evaluate the patterns, the number of components, and their possible link to physiology when FADS was applied to scintigraphic images representing a composite of a 81mKr ventilation cycle. In a study of 26 patients (10 normal, 16 pathologic), components were found that represent: (1) a rapid and steeply changing ventilation factor, corresponding mainly to bases in normal subjects and whole lung fields in patients, (2) a slower expiration and shorter inspiration ventilation factor distributed throughout both lung fields in all patients, (3) a constant activity curve, with an inspiratory activity peak distributed over both lung fields and the large airways, and (4) a factor including a phase shift with respect to the first; this was found significantly more often in patients with pathology.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00252743
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Diagnosis of malignancy in thyroid nodules by factor analysis of spectral and dynamic structures: a simultaneous dual-isotope dynamic study with thallium-201 and iodine-131 (1992)
    Springer
    European journal of nuclear medicine 19 (1992), S. 517-521 
    Details
    ISSN: 1619-7089
    Keywords: Dual-isotope studies ; Factor analysis ; Thallium thyroid uptake ; Thyroid nodule
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The aim of this study was to identify malignant thyroid nodules using iodine-123 and thallium-201 simultaneous dynamic acquisition. The image sequences acquired were processed by factor analysis of spectral and dynamic structures (FASDS). Some 49 patients were investigated, and their diagnoses were confirmed by histological examination. Data processing enables the estimation of the spectra of the two isotopes and the evaluation of the kinetics and spatial structures related to each tracer. The superimposition of thallium and iodide sum images allowed us to delineate the nodule accurately. Two groups were defined: 21 patients who had 201T1 uptake in the nodule, and 28 who had none. In the first group, 5 nodules were carcinomas, whereas all nodules in the second group were benign. The results of the 201T1 dynamic study improved the diagnosis of carcinoma as the number of false-positive cases decreased. FASDS succeeds in extracting spectral and kinetic information, proving its usefulness in clinical diagnosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00185858
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  • 3
    Electronic Resource
    Electronic Resource
    Factor analysis as a means of determining response to chemotherapy in patients with osteogenic sarcoma (1993)
    Springer
    European journal of nuclear medicine 20 (1993), S. 1175-1185 
    Details
    ISSN: 1619-7089
    Keywords: Dynamic bone scintigraphy ; Factor analysis ; Osteogenic sarcoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The prognosis of localized osteogenic sarcoma (OS) has improved considerably since the introduction of neoadjuvant chemotherapy. However, there is a subset of patients who do not show full benefit from neoadjuvant chemotherapy because of chemoresistance. The early identification of poor responders to chemotherapy during neoadjuvant therapy remains difficult. In order to evaluate the role of bone scintigraphy we report our experience of dynamic technetium-99m hydroxymethylene diphosphonate bone scintigraphy in 19 cases of paediatric osteogenic sarcomas. Before the beginning of chemotherapy, a dynamic scan was recorded during 30 min followed by static images at 3 h. The procedure was repeated halfway through the course of chemotherapy (6th week). Histological grading of the response to chemotherapy was carried out in the 12th week, showing nine good responses and ten poor responses. Factor analysis of dynamic structures (FADS) applied to dynamic scans allowed us to identify three factors termed vascular, “soft tissue” and osseous factors. The effect of chemotherapy on each factor was evaluated. Using FADS we were able to detect all the poor histological responders with the combination of vascular and osseous factors. Six out of nine good histological responders were also classified as scintigraphic responders. FADS applied to dynamic bone scans allowed us to identify at an early stage all the poor histological responders to neoadjuvant chemotherapy. This method may have clinical relevance for the therapeutic strategy in patients with OS.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00171016
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  • 4
    Electronic Resource
    Electronic Resource
    Early kinetics of the human thyroid trap estimated with 99mTc and 131I (1982)
    Springer
    European journal of nuclear medicine 7 (1982), S. 339-344 
    Details
    ISSN: 1619-7089
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Kinetic parameters of 99mTc and 131I thyroid trapping were compared in 13 patients (30 dynamic studies). The data were analyzed with a six-compartment model including three compartments for extrathyroid spaces. There was a good correlation between the estimates of the total iodide and pertechnetate pools (V4+V5). As expected, the λ14 loss rate constant for technetium was always higher than that for iodide. In five euthyroid patients, the unidirectional clearances (R41) with TcO4 − and I− were generally of the same magnitude. The effect of TSH stimulation appears to be identical for both isotopes: an increase of R41 and the total iodide and pertechnetate pool (V4+V5), a decrease of the isotope loss rate constant (λ14). In two untreated thyrotoxic patients, the unidirectional clearance of 99mTc was 2.5 times higher than that estimated with 131I. Under administration of antithyroid drug, unidirectional TcO4 − clearance was lower than that of iodide in the six patients studied. A similar and greater discrepancy between early 131I and 99mTc kinetics was observed in a patient with congenital goiter. The technetium thyroid trap was only slightly elevated, whereas unidirectional iodide clearance and (V4+V5) were clearly increased. This series of patients suggests that whereas there is a good correlation between early 131I and 99mTc kinetics in euthyroid subjects, a discrepancy exists in patients with spontaneous or acquired dyshormonogenesis. This is confirmed by the segmentary study of a patient with a nodule appearing hot on the 99mTc scintigram and cold on the 131I scan.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00255651
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  • 5
    Electronic Resource
    Electronic Resource
    Early kinetics of thyroid trap in normal human patients and in thyroid diseases (1981)
    Springer
    European journal of nuclear medicine 6 (1981), S. 317-326 
    Details
    ISSN: 1619-7089
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A six-compartment model is proposed for the study of early iodine kinetics (150 min) in the human thyroid gland including three compartments for extrathyroidal spaces. The results were compared with those obtained with an open two-compartment thyroidal model. In six euthyroid subjects the values of the unidirectional thyroid clearance R41=86±25 ml/min and of the irreversible clearance R65=22±9 ml/min were consistent with those generally accepted. With TSH stimulation a clear increase in the thyroidal pump effectiveness was found without an increase in the irreversible clearance. In four untreated thyrotoxic patients a tenfold increase in the unidirectional thyroid clearance was found (P〈0.01). The binding rate was much less increased and overlapped with the normal values; a large increase in the iodide compartment volumes was found. The unidirectional clearance remained elevated in seven patients after Carbimazole treatment and the binding rates were reduced. The six-compartment model demonstrated a rapid exit from the bound iodine compartment. In three of four goitrous patients studied, the thyroid unidirectional clearance was significantly increased (P〈0.001). The volumes of the iodide compartments were much higher than those observed in the other groups. The method was applied to analyse the kinetics of different parts of the thyroid.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00262526
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    Paper (German National Licenses)
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  • 6
    Electronic Resource
    Electronic Resource
    Comparison between factor analysis of dynamic structures and Fourier analysis in detection of segmental wall motion abnormalities: a clinical evaluation (1995)
    Springer
    The international journal of cardiovascular imaging 11 (1995), S. 263-272 
    Details
    ISSN: 1573-0743
    Keywords: radionuclide ventriculography ; Factor Analysis ; Fourier Analysis ; clinical evaluation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract To evaluate Factor Analysis of Dynamic Structures (FADS) versus or in association with other methods, a protocol was set up including as ‘gold standard’ investigation the left ventricular angiography (LVA) and processing by Fourier Analysis (FA), and FADS with different variants. To refine the diagnosis of Regional Wall Motion Abnormalities (RWMA), processing was done on a sectorial basis for more accurate spatial localization and functional description. 53 patients were studied (8 normal, 45 with coronary artery disease). FADS gave better results than FA on a sectorial basis. Total agreement between FADS and LVA was obtained in 208/265 (78%), while FA was in agreement with LVA in only 167/265 segments (63%). Globally, FADS was significantly better than FA (Z-test: p〈0.05). When only the diagnosis of maximal abnormality was considered, FA and FADS are statistically equivalent. The superiority of FADS vs FA is more obvious in the diagnosis of hypokinesia. Most FA discrepancies corresponded to underestimation of WMA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01145195
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    Paper (German National Licenses)
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