Asymmetric salivary gland 123I-meta-iodobenzylguanidine uptake in a patient with cervical neuroblastoma and Horner syndrome.
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3-Iodobenzylguanidine↗
Biomedical subjects
E Voth
Publications and source records attributed to E Voth.
Tc-99m MIBI SPECT correlated with magnetic resonance imaging for cardiac evaluation of a patient with congenitally corrected transposition of the great arteries (L-TGA).
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Adult↗
Identification of hemodynamically significant restenosis after percutaneous transluminal coronary angioplasty in acute myocardial infarction by transesophageal dobutamine stress echocardiography and comparison with myocardial single photon emission computed tomography.
BACKGROUND: Beside thrombolysis, percutaneous transluminal coronary angioplasty (PTCA) has become a well-established treatment for acute myocardial infarction. However, restenosis occurs in approximately 15%-40% of patients. Despite a frequently occurring infarct-related regional systolic dysfunction at rest, the identification of hemodynamically relevant restenosis seems important in terms of risk stratification, adequate treatment, and possible improvement of prognosis in these patients. This study was designed to assess the role of transesophageal dobutamine stress echocardiography and myocardial scintigraphy for identification of hemodynamically significant restenosis after PTCA for acute myocardial infarction. METHODS: Multiplane transesophageal stress echocardiography (dobutamine 5, 10, 20, 30, and 40 micrograms/kg per min) studies and myocardial single photon emission computed tomography (SPECT) studies were performed in 40 patients, all of whom underwent PTCA in the setting of acute myocardial infarction > or = 4 months prior to the test. Repeated coronary angiography was performed in all study patients who showed stress-induced perfusion defects or wall-motion abnormalities, or both. RESULTS: Significant restenosis (> or = 50%) was angiographically found in 15 (37.5%) of 40 patients. Of these 15 patients, transesophageal dobutamine stress echocardiography identified restenosis in 12 (80%) and myocardial SPECT in 14 (93%), yielding diagnostic agreement in 70% of patients. Echocardiographic detection of restenosis was based mainly on a biphasic response to increasing doses of dobutamine. Sensitivity and specificity for identification of hemodynamically relevant restenosis in individual patients was 80% and 92%, respectively for dobutamine stress echocardiography versus 93% and 68% for myocardial SPECT. CONCLUSIONS: Both transesophageal dobutamine stress echocardiography and myocardial SPECT were highly sensitive in identifying significant restenosis after PTCA for acute myocardial infarction. Therefore, either test, as a single diagnostic tool or especially if performed together, are clinically valuable alternatives to coronary angiography for the detection of restenosis after PTCA for acute myocardial infarction.
Acute Disease↗
[Influence of stable iodine on the uptake of the thyroid--model versus experiment].
AIM: The influence of physiological and pharmacological amounts of iodine on the uptake of radioiodine in the thyroid was examined in a 4-compartment model. This model allows equations to be derived describing the distribution of tracer iodine as a function of time. The aim of the study was to compare the predictions of the model with experimental data. METHODS: Five euthyroid persons received stable iodine (200 micrograms, 10 mg). I-123-uptake into the thyroid was measured with the Nal(Tl)-detector of a body counter under physiological conditions and after application of each dose of additional iodine. Actual measurements and predicted values were compared, taking into account the individual iodine supply as estimated from the thyroid uptake under physiological conditions and data from the literature. RESULTS: Thyroid iodine uptake decreased from 80% under physiological conditions to 50% in individuals with very low iodine supply (15 micrograms/d) (n = 2). The uptake calculated from the model was 36%. Iodine uptake into the thyroid did not decrease in individuals with typical iodine supply, i.e. for Cologne 65-85 micrograms/d (n = 3). After application of 10 mg of stable iodine, uptake into the thyroid decreased in all individuals to about 5%, in accordance with the model calculations. CONCLUSION: Comparison of theoretical predictions with the measured values demonstrated that the model tested is well suited for describing the time course of iodine distribution and uptake within the body. It can now be used to study aspects of iodine metabolism relevant to the pharmacological administration of iodine which cannot be investigated experimentally in humans for ethical and technical reasons.
Biological Transport↗
[Radioiodine therapy of Graves' disease--a dosimetric comparison of various therapy regimens of antithyroid agents].
AIM: Premedication with antithyroid drugs (ATD) compared to patients not pretreated with ATD causes a higher failure rate of radioiodine therapy (RITh) or demands higher therapeutical dosage of radioiodine (RI). For clinical reasons and because of accelerated iodine metabolism in hyperthyreosis a compensated thyroid metabolism is desirable. Aim of this study was to investigate the influence of ATD on the biokinetics of RI in case of Graves' disease in order to improve RITh of patients pre-treated with ATD. METHODS: 385 consecutive patients who underwent RITh because of Graves' disease for the first time were included: Group A (n = 74): RITh under continuous medication with ATD; Group B (n = 111): Application of RI under continuous medication with ATD, in case of insufficient RI-uptake or shortened effective RI-half-life ATD were stopped 1-5 days after RITh; Group C (n = 200): ATD were stopped 2 days prior to RITh in all patients. We examined the influence of ATD on RI-uptake and effective RI-half-life as well as the absorbed dose achieved on the thyroid in dependence of thyroid volume and applied RI-dosage [TEQ--therapy efficiency quotient, (2)]. RESULTS: In the RI-pretest (all patients under ATD) the RI-uptake was comparable in all three groups. During RITh RI-uptake, effective RI-half-life and therefore the TEQ were significantly higher in Group C as compared to Groups A and B (p < 0.001, respectively). In Group B the medication with ATD was stopped in 61 of 111 cases 1-5 days after RITh. In this subgroup the effective RI-half-life increased from 4.4 +/- 1.7 d to 5.1 +/- 1.6 d after stopping of ATD (p = 0.001). CONCLUSION: Stopping of ATD 2 days prior to RITh leads to an increased efficiency of about 50% compared to RITh carried out under ATD and therefore to a clear reduction of radiation exposure to the rest of the body with equal absorbed doses of the thyroid. Stopping of ATD shortly after RITh increases efficiency in case of short effective RI-half-life, but it is inferior to stopping ATD 2 days prior to RITh.
Adolescent↗
[Comparison of dobutamine-stress magnetic resonance imaging and dipyridamole-TL-201-SPECT as alternative strategies for the detection of coronary artery dis in patients no suitable for stress echocardiography].
AIM: During the past decade stress-echocardiography has gained increasing popularity for detection of myocardial ischemia in patients with coronary artery disease. However, about 10% to 15% of the patients submitted for stress-echocardiography do not have an adequate acoustic window. The purpose of this study was to compare high-dose dobutamine-stress magnetic resonance imaging (dobutamine-MRI) with dipyridamole-Tl-201-SPECT (dipyridamole-SPECT) as alternative strategies for detection of myocardial ischemia in patients with inadequate image quality by stress-echocardiography. PATIENTS AND METHODS: Of 296 patients which were consecutively submitted to stress-echocardiography 45 patients (15%) had two or more segments that could not be evaluated according to the 16-segment-model of the American Society of Echocardiography. They underwent dobutamine-MRI and dipyridamole-SPECT studies, which were evaluated using a 28-segment modell. Myocardial segments were attributed to perfusion territories of the coronary arteries. The results of ischemia detection were compared to the results of coronary angiography (stenosis > or = 50%). RESULTS: In comparison to coronary angiography dobutamine-MRI yielded a sensitivity of 87%, a specificity of 86%, a positive predictive value of 93%, a negative predictive value of 75% and a diagnostic accuracy of 86%. For dipyridamole-SPECT results were 90%, 86%, 93%, 80% and 89%, respectively. These values were not significantly different. CONCLUSIONS: In patients not suitable for stress-echocardiography, both dobutamine-MRI and dipyridamole-SPECT are reliable strategies for detection of myocardial ischemia. Selection is dependent on the patient criteria, technical considerations, local logistics and experience of the observer.
Adrenergic beta-Agonists↗
Preoperative localization of parathyroid adenomas using 99mTc-MIBI scintigraphy.
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Adenoma↗
[Dobutamine-induced changes in the myocardial blood flow in patients with coronary heart diseases. A quantitative analysis using [15O] H2O positron emission tomography].
BACKGROUND AND OBJECTIVE: Although dobutamine is currently widely used for stress testing, only little is known about the effects of dobutamine on myocardial blood flow. The purpose of the present study was therefore to analyze quantitatively the regional changes in myocardial blood flow during rest and stress. PATIENTS AND METHODS: In order to assess these effects 17 patients (12 men, five women, mean age 57 +/- 8 years) with symptomatic single vessel coronary artery disease (> 70% stenosis) scheduled for coronary angioplasty underwent dobutamine stress testing with a maximum dose of 40 micrograms/kg/min. Myocardial blood flow was measured using 15O H2O position emission tomography at rest and during maximum stress in ischemic and non-ischemic myocardial regions. RESULTS: Dobutamine stress (median dose 30 micrograms/kg/min) increased the rate pressure product significantly (from rest 8697 [95% confidence interval 7959-9435] to stress 16,512 [15,208-17,815] mmHg/min (p < 0.001). Myocardial blood flow during rest was similar in non-ischaemic and ischaemic regions (0.91 [0.93; 0.83-1.28] vs. 1.10 [1.23; 0.91-1.28] ml/min/g, n.s.). During dobutamine stress myocardial blood flow increased in non-ischaemic regions to 2.17 (2.15; 1.77-2.57) ml/min/g, while myocardial blood flow did not increase in ischaemic regions (1.06 [0.97; 0.83-1.28], p < 0.001). Accordingly, dobutamine coronary reserve was 2.42 (2.55; 2.10-2.74) for non-ischaemic regions and 0.98 (1.05; 0.84-1.13) for ischemic regions (p < 0.001). Rate pressure product and myocardial blood flow were significantly correlated (r = 0.79, p < 0.001). CONCLUSION: A dobutamine-induced increase in rate pressure product was proportional to an increase in myocardial blood flow in non-ischaemic regions. In contrast, myocardial blood flow did not increase in myocardial regions supplied by a severely stenosed coronary artery.
Blood Flow Velocity↗
Iterative reconstruction: an improvement of technetium-99m MIBI SPET for the detection of parathyroid adenomas?
The purpose of this study was to assess the value of technetium-99m methoxyisobutylisonitrile (MIBI) single-photon emission tomography (SPET) and an iterative reconstruction algorithm for the preoperative localisation of parathyroid adenomas (PTAs). Seventy-two patients (26 male, 46 female, mean age 58+/-16 years) with known primary hyperparathyroidism were examined preoperatively. First, a thyroid examination was performed to detect possible MIBI-accumulating thyroid lesions. Planar scans were then acquired 15 and 120 min and tomographic images 120 min after intravenous injection of 740 MBq 99mTc-MIBI, using a triple-head gamma camera (Picker Prism 3000). Additionally, 99mTc-MIBI/ 99mTc-pertechnetate subtraction scintigraphy of the early planar images was performed. The SPET data were evaluated using an iterative reconstruction (multiplicative iterative SPET reconstruction: MISR) as well as a standard algorithm (FBP: filtered back-projection with application of a 3-D low-pass postfilter). The weight of the resected PTAs ranged from 110 mg to 5 g. Using planar MIBI scans, correct localisation of the side of the PTA was possible in 81% of cases (58% for PTAs weighing less than 500 mg). Sensitivity increased to 94% using SPET and FBP, while with MISR it rose further, to 97%. Patients with PTAs weighing less than 500 mg showed a sensitivity of 88% with MISR and 81% with FBP. Furthermore, there was a clear improvement in image quality using MISR. None of the normal parathyroid glands were visualised. This study indicates that, in comparison with planar scintigraphy, 99mTc-MIBI SPET is a more sensitive and specific tool for topographical localisation of PTAs, especially those that are small. There is a further improvement in sensitivity and image quality when iterative reconstruction is used instead of FBP.
Adenoma↗
Glucose metabolism of the thyroid in autonomous goiter measured by F-18-FDG-PE.
The radiolabeled glucose analogue F-18-Fluoro-Deoxyglucose (F-18-FDG) and Positron Emission Tomography (PET) were used to measure glucose metabolism of the thyroid in vivo. We evaluated patients with autonomous goitre before therapy with radioiodine in comparison to patients with normal thyroids. 30 patients with autonomous goitre underwent scanning the day before radioiodine therapy. 19 patients with head or brain tumours and normal thyroids were the controls. Overall F-18-FDG uptake was determined for all thyroids and proved to be significantly higher in autonomy patients compared to controls and in disseminated autonomous goitre slightly but not significantly higher than in focal autonomy. In autonomy patients F-18-FDG uptake increased with increasing radioiodine uptake and shorter radioiodine half-life. These results indicate that glucose metabolism is enhanced in the thyroids of patients with focal and disseminated autonomy. The negative correlation of radioiodine half-life and glucose metabolism as well as the positive correlation of radioiodine uptake and glucose metabolism suggest connections of glucose metabolism and iodine-dependent hormone synthesis in thyroid cells.
Adenoma↗
Technetium 99m-MIBI-SPECT: A highly sensitive diagnostic tool for localization of parathyroid adenomas.
BACKGROUND: The aim of this study was to assess the value of technetium 99m-MIBI scintigraphy using the single photon emission computed tomography (SPECT) technique for preoperative localization of smaller (</= 1 g) parathyroid adenomas. METHODS: A total of 92 patients (34 men, 58 women; mean age, 60 +/- 13 years) with an established diagnosis of primary hyperparathyroidism and nondiagnostic ultrasonography (inclusion criteria) were scanned preoperatively. After a thyroid examination to check for other possible radionuclide-accumulating thyroid diseases, a planar technetium 99m-pertechnetate/technetium 99m-MIBI subtraction scintigraphy (15 minutes post injection) and tomographic images (120 minutes post injection) were acquired after intravenous injection of 740 MBq of technetium 99m-MIBI and using a 3-head gamma camera (Picker Prism 3000). Sensitivity was defined by the ability to predict the correct site of a parathyroid adenoma. RESULTS: All patients had parathyroid adenomas </= 1 g (53 patients, 0.5 -1.0 g; 39 patients, < 0.5 g). Correct localization of parathyroid adenomas to one side or the other was achieved in 87% of the patients using planar technetium 99m-pertechnetate/technetium 99m-MIBI subtraction scintigraphy. Sensitivity was increased to 95% by supplementary use of the SPECT technique and a 3-D display (volume-rendered reprojection for visualization). There was technetium 99m-MIBI accumulation in 11 benign thyroid nodes, but none of the healthy parathyroid glands were shown on the scan. CONCLUSIONS: This study indicates that technetium 99m-MIBI parathyroid scintigraphy is a sensitive and specific tool for topographic localization even of small parathyroid adenomas, especially with the use of SPECT. This method could help to improve the efficiency of parathyroidectomy (eg, by making unilateral exploration sufficient).
Adenoma↗
Hypothyroidism after therapy for larynx and pharynx carcinoma.
Early detection of local and regional recurrence is the main goal during follow-up of patients with larynx and pharynx cancer. Hypothyroidism occurring in those patients stays frequently undiagnosed as screening for hypothyroidism is not part of the routine follow-up. This study was performed to assess the prevalence of hypothyroidism in these patients. We included 120 patients (106 male, 14 female) with larynx or pharynx cancer treated more than 2 months earlier (mean = 41 months) in the study. Cancer treatment consisted of either surgery (n = 44), radiotherapy (n = 15), or surgery combined with postoperative radiotherapy (n = 61). In all patients, thyroid function studies (thyrotropin [TSH], free triiodothyronine [FT3], and free thyroxine [FT4]) were performed. Twenty-six of all patients (22%) were hypothyroid; in two patients hypothyroidism was diagnosed postoperatively and these two patients were on replacement therapy with thyroid hormones. The highest rate of hypothyroidism (34%) was present in patients treated with surgery combined with radiotherapy, whereas among patients treated with surgery only 7% were hypothyroid (p < 0.001). There was no difference in the duration of follow-up between therapy and inclusion in the study between those two groups. Two of 15 patients treated only with radiotherapy were diagnosed hypothyroid, but in this group the latency was shorter (p < 0.05). The results indicate that thyroid function studies should be routinely performed in the follow-up of head and neck cancer patients, especially if radiotherapy was part of the treatment.
Aged↗
Follow-up of differentiated thyroid cancer: comparison of multiple diagnostic tests.
The radioablation of thyroid remnants improves the prognosis of differentiated thyroid cancer. In our prospective study an activity of 3.7 GBq 131I failed to completely ablate the remnants in 46 out of 101 patients, but a 3-year follow-up period was uneventful. One other patient had a recurrence early after thyroidectomy. In view of possible stunning effects of 131I it might be advantageous to visualize such remnants by imaging modalities which do not emit beta-particles. Our data have revealed that neither magnetic resonance imaging (MRI), nor ultrasonography (US), nor 99Tcm-sestamibi scintigraphy, nor positron emission tomography could detect or reliably exclude minimal remnants. Such remnants did not produce thyroglobulin (Tg). A 123I and 131I uptake of> 10% after thyroidectomy was associated with about a 90% probability of persistent remnants. On the other hand, MRI was helpful in the patient group (n = 32) with Tg>4ng x ml(-1) at the second whole-body scintigraphy (TSH>30 mU x l(-1)) for planning the management of lymph node metastases (n = 15 patients): 12 patients had subsequent surgery and three patients radioiodine therapy. We recommend that MRI be used early in follow-up care when Tg is elevated. The decision of whether or not to treat persistent thyroid remnants should not be made on the basis of MRI, US or nonspecific scintigraphic methods. Complete ablation did not appear to have any clinical benefit in our study group.
Adolescent↗
[Metastasizing follicular thyroid carcinoma with intracranial iodine 131 uptake in brain edema due to a frontal meningioma].
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Adenocarcinoma, Follicular↗
[Sonographic determination of thyroid volume--comparison with surgical data].
AIM: Objective of this prospective study was to find out, if especially the volume of large nodular goitres can be determined accurately by using ultrasonography and the ellipsoid model. METHODS: 100 patients with different thyroid disorders, who all underwent a thyroid resection, were examined by a single experienced investigator. The preoperative thyroid volume was determined by ultrasonography and correlated to the sum of surgically removed and postoperative thyroid volume determined by ultrasound. RESULTS: Patients included had thyroid volumes between 12 and 450 ml (mean value 89 ml). Within the whole study group, coefficients of correlation and variation were r = 0.90 and CV = 0.29, respectively. The mean difference between the thyroid volume determined preoperatively by ultrasonography and the sum of surgically removed and postoperative thyroid volume was 3 +/- 27 ml or 13 +/- 38%. Excluding patients with retrosternal goitres or cysts with a diameter > 2 cm, the correlation coefficient increased to r = 0.95 (CV = 0.21) and mean differences decreased to 2 +/- 20 ml and 9 +/- 30%. Further subdivision according to thyroid volume (< or = 50 ml, < or = 100 ml, > 100 ml) revealed no significant influence of thyroid volume on the accuracy of ultrasound volume determination. Subdividing the study collective according thyroid disorders, relevant deviations of preoperative sonographic thyroid volume from the sum of surgically removed and postoperative thyroid volume were observed in case of retrosternal goitre (19 +/- 62%), cystic degeneration (41 +/- 52%) and Graves' disease (23 +/- 29%). CONCLUSION: These results show, that even large suprasternal goitres > 100 ml can be sufficiently determined by ultrasound by an experienced examiner.
Adult↗
[Effect of iodine application during radioiodine therapy in patients with impending therapy failure].
AIM: We investigated whether additional application of "cold" iodine after therapy with radioiodine could result in a prolongation of the effective half life of iodine-131 and would thus lead to an increase of the effective thyroid radiation dose. METHODS: Time-activity-curves after therapy with radioiodine were analysed in 25 patients (16 women, 9 men). Nine patients suffered from autonomously functioning thyroid nodules, 5 from autonomous multinodular goiter and 11 from Graves' disease. These patients had an effective half life shorter than 4 days resulting in an undertreatment of > 20% with respect to the desired effective thyroid radiation dose. 2-4 days after therapy with radioiodine all patients received "cold" iodine for three days in a dose of 3 x 200 micrograms per day. RESULTS: In 14 of the 25 patients an increase of the effective half life was observed. Patients with an autonomously functioning thyroid nodule showed a mean increase of the effective thyroid radiation dose of 40 +/- 44 Gy, patients with toxic multinodular goiter of 29 +/- 30 Gy and patients with Graves' disease of 37 +/- 37 Gy. CONCLUSION: Additional application of "cold" iodine after therapy with radioiodine can prolong the effective half life in selected patients. We suspect a correlation with the thyroid iodine pool. This will be the basis for further investigations hopefully resulting in a better patient preselection to determine who might respond to this therapy.
Adult↗
[Clinical value of magnetic resonance tomography in imaging coronary stenoses. A comparison with coronary angiography and myocardial scintigraphy].
BACKGROUND AND OBJECTIVE: The development of ultra-rapid gradient-echo sequence magnetic resonance imaging (MRI) makes it possible to visualize coronary arteries. But the clinical value of coronary artery MRI (MRCA) still needs to be established. It was the aim of this study to determine whether MRCA can demonstrate proximal parts of the coronary arteries and visualize haemodynamically relevant stenoses. PATIENTS AND METHODS: MRCA was performed, using segmented 2D sequences and a navigator pulse, in 29 patients (22 men, seven women, mean age 60 +/- 10 years) in whom coronary heart disease (CHD) was suspected or who, with proven CHD (> or = 50% stenosis) further treatment was to be established. Exercise myocardial scintigraphy with single proton emission tomography (SPECT) was additionally performed in 20 of the patients. RESULTS: Seven of 87 coronary arteries (8%) could not be demonstrated because the patients' claustrophobia necessitated premature termination of the investigation: these vessels were excluded from the final analysis. The mean length of the visualized coronary arteries was 12 +/- 4 mm for the main stem (LM), 36 +/- 14 mm for the left interventricular branch (LAD), 18 +/- 12 mm for the circumflex branch (CX) and 67 +/- 23 mm for the right coronary artery (RCA). Of 37 stenoses demonstrated by coronary angiography 29 were also visualized by MRCA: 13 of 18 LAD stenoses, two of three CX stenoses and 14 of 16 RCA stenoses. Mean sensitivity of MRCA was 78%, mean specificity 86%. In patients who had undergone exercise SPECT, coronary angiography demonstrated 26 stenoses, of which 16 (six LAD, two CX and eight RCA stenoses) were haemodynamically significant. Of these 16 stenoses MRCA demonstrated 13, but three stenoses (one RCA and two LAD stenoses) were not visualized, because the stenoses were distal to the demonstrated segments. CONCLUSION: MRCA can visualize moderately severe stenoses, especially of the proximal coronary arterial segments. This method represents an new approach to noninvasive diagnosis of CHD, but additional technical improvements will have to be made.
Adult↗
Stress functional MRI: detection of ischemic heart disease and myocardial viability.
Breath-hold gradient-echo magnetic resonance imaging (MRI) in conjunction with pharmacologic dobutamine stress has become a practical tool to investigate patients with chest pain. The presence of high-grade coronary artery stenoses can be detected more accurately than with stress echocardiography. The main diagnostic advantage of MRI is in patients with suboptimal echocardiographic image quality. Depiction of left ventricular anatomy and function at rest and during low-dose dobutamine stress is also clinically useful for evaluating patients with severely impaired left ventricular function for the presence of residual myocardial viability. Recovery of regional and global left ventricular function can be accurately predicted by stress functional MRI. J. Magn. Reson Imaging 1999;10:667-675, 1999.
Cardiotonic Agents↗