Methodological considerations influence the clinical value of parathyroid localisation diagnostics.
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Humans↗
Biomedical subjects
C Bacher-Stier
Publications and source records attributed to C Bacher-Stier.
Identification of severe and extensive coronary artery disease by postexercise regional wall motion abnormalities in Tc-99m sestamibi gated single-photon emission computed tomography.
Postexercise wall motion abnormality (WMA) in patients with normal resting myocardial perfusion may represent prolonged postischemic stunning, and may be related to the presence of severe angiographic coronary artery disease (CAD). This study assesses the diagnostic value of postexercise WMA by technetium-99m (Tc-99m) sestamibi gated single-photon emission computed tomography (SPECT) in patients with normal resting perfusion. Ninety-nine patients underwent exercise gated Tc-99m sestamibi/resting thallium-201 SPECT and coronary angiography within 90 days of nuclear testing. All patients had normal perfusion at rest. Multivariate logistic regression analysis demonstrated an incremental value of wall motion and perfusion over perfusion data alone in identifying severe and extensive CAD. Sensitivity for identifying any severely stenosed coronary artery by WMA was significantly higher than by severe perfusion defect (78% vs 49%, p <0.0001). Overall specificities of severe perfusion defect and WMA were 91% and 85%, respectively (p = NS). Thus, postexercise WMA detected by gated Tc-99m sestamibi SPECT in patients with normal resting perfusion is a sensitive marker of severe and extensive CAD.
Aged↗
Postexercise lung uptake of 99mTc-sestamibi determined by a new automatic technique: validation and application in detection of severe and extensive coronary artery disease and reduced left ventricular function.
UNLABELLED: This study validated a new automatic algorithm for assessment of lung-to-heart ratio (L/H) of radiotracers in myocardial perfusion SPECT and assessed the diagnostic value of (99m)Tc-sestamibi L/H after exercise. METHODS: The new technique extracts a left ventricular region of interest (ROI) from a summed anterior projection image and generates a lung ROI by reshaping and translating the left ventricular ROI. This algorithm was applied to 230 patients who underwent exercise (99m)Tc-sestamibi SPECT (gated SPECT, n = 88) with first-pass ventriculography. Normal values were established in 26 patients in whom the likelihood of coronary artery disease (CAD) was 5% or less. An abnormality threshold for detecting severe and extensive CAD was defined in a subgroup of 109 patients who underwent coronary angiography and was validated in a prospective group (n = 72). RESULTS: The success rate of the automatic algorithm was 97%. Excellent correlation was found between automatic and manual L/H values (r = 0.95; P < 0.001). The mean L/H was higher in patients with a peak exercise ejection fraction (EF) less than 40% versus 40% or more (0.51 +/- 0.07 versus 0.43 +/- 0.05, P < 0.001) and in patients with a poststress EF less than 40% versus 40% or more (0.50 +/- 0.07 versus 0.44 +/- 0.06, P < 0.01). A threshold of L/H greater than 0.44 yielded a sensitivity and specificity of 63% and 81%, respectively, for identifying severe and extensive CAD in the prospective group and a sensitivity of 86% in identifying stenosis of 90% or more in the proximal left anterior descending artery. CONCLUSION: The new automatic algorithm for assessing L/H correlated well with manually derived L/H for (99m)Tc-sestamibi as well as (201)TI SPECT. An increased postexercise (99m)Tc-sestamibi L/H adds significant diagnostic value to study myocardial perfusion SPECT as a marker of severe and extensive CAD and reduced ventricular function.
Aged↗
Thallium-201 gated single-photon emission tomography for the assessment of left ventricular ejection fraction and regional wall motion abnormalities in comparison with two-dimensional echocardiography.
Simultaneous assessment of myocardial perfusion and function by gated single-photon emission tomography (GS) after a single tracer injection provides incremental information and is feasible with technetium-99m sestamibi. The present study validated the use of GS with thallium-201 for the assessment of left ventricular ejection fraction (LVEF) and regional wall motion by comparison with two-dimensional (2D) echocardiography (echo), which has not been done before. After injection of 111 MBq 201Tl at peak bicycle exercise (n = 55) or pharmacological stress (n = 17), GS was acquired 15 (post stress) and 120 min post injection (rest) on a double-head camera. An automatic algorithm (QGS) was used for processing. Echo (Acuson Sequoia C256) was performed immediately after rest GS. LVEFs assessed by GS and echo were correlated. The overall and segmental sensitivity and specificity of GS for the detection of regional wall motion abnormalities (WMAs) were calculated, echo serving as the gold standard. Perfusion abnormalities were scored. The success rate of the automatic algorithm was 100%, and visually assessed image quality was good to excellent in 88% of cases. Post-stress and rest LVEF as assessed by GS were highly correlated (r = 0.91). Good correlations were obtained between post-stress LVEF (GS) and rest LVEF (echo) and between rest LVEF (GS) and rest LVEF (echo) (r = 0.76 and 0.86 respectively). In patients with a reduced LVEF of less than 50% (n = 23), these correlations were even better (r = 0.84 and 0.89 respectively). Regional wall motion abnormalities (WMAs) were identified by GS with high sensitivity and specificity (88%-100% and 82%-98% respectively) and were directly related to the extent and severity of stress as well as of resting perfusion defects. It is concluded that GS with 201Tl is a feasible and reliable tool for the evaluation of patients with compromised left ventricular function in the context of coronary artery disease, and thus improves diagnosis and prognostic stratification. Regional WMAs were identified with high diagnostic accuracy and the method may prove helpful for the detection of myocardial viability.
Female↗
One year's clinical experience of 18F-FDG PET with a modified SPET camera using molecular coincidence detection.
High-quality positron emission tomographic (PET) cameras are expensive and, therefore, not available in many centres. To allow access to clinical 18F-fluorodeoxyglucose (18F-FDG) PET, we began working with an ADAC Vertex camera equipped with a molecular coincidence detection (MCD) module in February 1997. Here we give a preliminary assessment of the clinical utility of our approach. To date, 109 studies have been performed in MCD-mode using standardized protocols (99 oncology cases, 10 neurology cases). Twenty-eight cardiological and 15 other studies were performed using 511 keV collimators without attenuation correction. The average dose of 18F-FDG for MCD studies was 150 MBq, thus avoiding overloading the detectors; cardiac studies required 370 MBq. The results obtained were carefully compared with computed tomography, magnetic resonance imaging, myocardial perfusion scans, coronary angiography and conventional radiology. The results were compared on a patient basis, including histology, surgical notes, autopsy reports and follow-up data. Oncological studies were performed to assess malignancy in a particular lesion (n = 22), staging of cancer (n = 57) or to evaluate whether therapy had been successful or not (n = 20). Indications for conducting studies were categorized as appropriate (Ia) or adequate (Ib). For Ia category cases, the results were: true-positive = 31, true-negative = 12 and false-positive = 2. For Ib category cases, the corresponding figures were: true-positive = 18, true-negative = 10, false-positive = 3 and false-negative = 1. False-positive studies were a result of inflammatory disease or artefacts. Six cases with temporal lobe epilepsy were correctly identified. In cardiac studies, we also found a good correlation with clinical parameters (i.e. hibernating myocardium or scarred tissue). Altogether, this cost-effective set-up allows nuclear medicine institutions to obtain valuable data in clinical practice with a system used both for single photon emission tomography and PET.
Coronary Disease↗
Incidence and clinical characteristics of thyroid carcinoma after iodine prophylaxis in an endemic goiter country.
Iodized salt prophylaxis has been performed in Austria since 1963. Through this approach, mean urinary iodine excretion has been normalized to 144+/-23.5 microg/g creatinine per day. Thus Tyrol is no longer an endemic goiter area. We have analyzed the impact of iodized salt prophylaxis on thyroid cancer (TC) comparing data from the early 1960s with those corresponding to the period 1986 to 1995, when iodine supply was normalized. The study included 439 patients from Tyrol and Southern Tyrol. The incidence of TC in Tyrol has risen during the past decades from 3.07 between in 1957 and 1970 to 7.8 between 1990 and 1994 (CR/100000/year). We observed a rise in the percentage of differentiated adenocarcinomas (56% to 91.5%) with a predominance of papillary TC (54.4%) along with a decrease of anaplastic TC. In addition to these histological features, a shift to less advanced TNM stages, eg, T1-3, N0-1a, M0, was obvious, increasing from 29% to 72.2%, whereas advanced tumors, ie, T4 or N1b or M1, decreased from 71% to 28%. These changes have significantly improved prognosis. The current 5-year survival rate is 90.7% as compared with a rate of 73% in the 1960s; the values for 7-year survival are 89% and 48%, respectively. The marked effects of age, tumor stages, and histology on prognosis were confirmed with the Kaplan-Meier method. We conclude that together with normalization of iodine supply in an endemic goiter region the epidemiological profile of TC has changed. Even though the incidence of TC has risen, prognosis has significantly improved due to a shift towards differentiated forms of TC that are diagnosed at earlier stages.
Age Factors↗
beta 1-Integrin expression in papillary thyroid carcinoma.
beta 1-integrins are widespread adhesion molecules which belong to a family of heterodimeric membrane glycoproteins and consist of two subunits, alpha and beta. Integrins seem to play an important role in the spreading and metastasis of malignant tumors. We investigated the expression and distribution of these adhesion molecules on papillary thyroid carcinomas by immunohistochemistry on formalin-fixed, paraffin embedded cancer tissues. We estimated the beta 1-integrin expression in cancerous areas in comparison to normal adjacent thyroid tissue. Our results revealed a highly significant difference in all investigated parameters between cancer and normal thyroid cells (p < 0.0001). Comparing our findings with the metastatic potential of the primary thyroid tumors, our results show that beta 1-integrin expression could be used as a prognostic parameter for papillary thyroid tumors.
Carcinoma, Papillary↗