Radioiodine treatment of Graves' disease - dose/response analysis.

The clinical outcome of 153 Graves' disease patients treated with a wide dose range of radioactive iodine-131 (RAI) was analyzed retrospectively. Six to nine months after the first dose of RAI 60 patients (39%) were hypothyroid (or rather thyroxine-substituted) and 26 (17%) were euthyroid, while 67 patients (44%) did not respond properly: in 32 (21%) their antithyroid drug (ATD) dose could be reduced but not withdrawn (partial response) and 35 (23%) remained hyperthyroid or the same dose of ATD was necessary (no response). The outcome did not correspond significantly to the administered activity of RAI (medians 259, 259, 222, and 259 MBq for hypothyroid, euthyroid, partial, and no response subgroups, respectively), or the activity retained in the gland at 24 h (medians 127, 105, 143, and 152 MBq). The effect was, however, clearly, and in a stepwise pattern, dependent on initial thyroid volume (17, 26, 33 and 35 ml, P < 0.001) or activity per gram tissue retained at 24 h (6.02, 4.95, 4.75, and 4.44 MBq/g, P = 0.002). Also, higher residual level of thyrotoxicosis at the time of RAI treatment was connected with worse outcome. The dose-dependency of outcome was further analyzed. When our sample was divided into tertiles, according to the adjusted dose, the same modest success rates (47%) were seen in the lower and middle tertiles. However, doses higher than 5.88 MBq/g (the upper tertile) resulted in success rate of 75%. Finer division into decils has shown a threshold-like increase in cure rate between the 7th and the 8th decil. In the first 7 decils (doses ≤ 6 MBq/g) the complete response rate was 45 to 50%, in the 8th decil (6.0 to 7.8~MBq/g) it rose to 80% and was not further increased with increasing dose. Direct comparison of higher (> 6 MBq/g, cure rate 80%) and lower (≤ 6 MBq/g, cure rate 46%) doses gave highly significant difference (P < 0.001). With our dosing range we found a dose-dependent clinical outcome that suggests an optimum delivered dose near 6.5 MBq/g, resulting in successful treatment of ca 80% patients.

Single-photon emission computed tomography enhanced Tc-99m-pertechnetate disodium-labelled red blood cell scintigraphy in the localization of small intestine bleeding: a single-centre twelve-year study.

AIM: To present our experience with the detection of bleeding in the small intestine by means of scintigraphy with in vivo-labelled red blood cells (RBCs) in the period of 1998-2009. MATERIALS AND METHODS: A 12-year prospective study was accomplished with 40 patients (23 men, 17 women, aged 12-91, mean 56 years) who had lower gastrointestinal bleeding (obscure-overt bleeding) and underwent scintigraphy with in vivo-labelled RBCs by means of technetium 99m. The scintigraphy was usually performed after other diagnostic tests had failed to locate the bleeding. RESULTS: A total of 26 patients had a positive scintigraphy with in vivo-labelled RBCs and 14 patients had negative scintigraphy. The final diagnosis was confirmed in 20 of 26 patients with a positive scintigraphy by push enteroscopy (6/20), intraoperative enteroscopy (7/20), surgery (4/20), duodenoscopy (1/20), double-balloon enteroscopy (1/20) and X-ray angiography (1/20). The correct location of the bleeding site was identified by RBC scintigraphy in 15 of 20 (75%) patients with the confirmed source. The locations of the bleeding site identified by scintigraphy and enteroscopy (push, intraoperative) and surgical investigations were highly correlated in patients with a positive scintigraphy within the first 3 h. Eleven of the 20 correctly localized studies and none of the incorrectly localized studies were positive in the dynamic phase of imaging. In 5 patients (all erroneously localized), scintigraphy was positive only at a period longer than 18 h. CONCLUSION: RBC scintigraphy is an effective imaging modality in localizing lower gastrointestinal bleeding in patients for whom other diagnostic tests have failed to locate the bleeding. RBC scintigraphy can be successful in the detection of bleeding sites in the small intestine.

Prothrombotic changes due to an increase in thyroid hormone levels.

OBJECTIVE: With increasing free thyroxine levels, a gradually rising risk of venous thromboembolism has been described in case-control studies. However, reports on the influence of thyroid hormones on haemostasis, while suggesting a hypercoagulable state in thyrotoxicosis, have often been inconclusive. This study evaluates multiple markers of haemostasis and fibrinolysis in a paired design, making it more sensitive to changes in thyroid hormone levels. DESIGN: We analysed multiple variables in patients who shifted from severe hypothyroidism to mild hyperthyroidism during thyroid cancer treatment. Those with possible residual disease were excluded. METHODS: Ninety patients following total thyroidectomy were tested on two occasions: i) before radioiodine remnant ablation and ii) 6 weeks later, on levothyroxine (lT4) suppression treatment, and the results were compared using the Wilcoxon's test for paired data. RESULTS: During lT4 treatment, significant increases (all P<0.001) in fibrinogen (from median 3.4 to 3.8 g/l), von Willebrand factor (from 85 to 127%), factor VIII (from 111 to 148%) and plasminogen activator inhibitor 1 (from 6.5 to 13.9 µg/l) were observed. In addition, the activation times of platelet adhesion and aggregation stimulated with collagen and epinephrine (EPI)/ADP, i.e. closure times in platelet function analyser (PFA-100), were significantly shortened (P<0.001): for EPI from median 148 to 117 s and for ADP from 95 to 80 s. Changes in other tests were less prominent or insignificant. CONCLUSIONS: An increase in thyroid hormone levels shifts the haemostatic balance towards a hypercoagulable, hypofibrinolytic state. This may contribute to the increased cardiovascular morbidity and mortality observed even in mild thyrotoxicosis.

Universal screening detects two-times more thyroid disorders in early pregnancy than targeted high-risk case finding.

OBJECTIVE: Screening of thyroid disorders in pregnancy has been controversial. Recent recommendations favour targeted high-risk case finding, though this approach may miss a significant number of those affected. We aimed to assess the prevalence of accepted high-risk criteria in women with autoimmune thyroiditis and/or hypothyroidism detected from universal screening in an iodine-sufficient population. DESIGN: In 400 non-selected women in the 9-11th gestational week, thyroid-related tests were performed, and those with abnormalities were offered consultation. METHODS: TSH was determined by IRMA, and the upper cut-off value for screening was set at 3.5 mIU/l. For free thyroxine (FT(4)) and thyroperoxidase antibodies (TPO-Ab), RIAs were used, with cut-offs of <10 pmol/l and >50 IU/ml respectively. Endocrinological consultation included Doppler ultrasonography and was aimed to confirm autoimmune thyroiditis and/or hypothyroidism. The prevalence of consensus high-risk criteria was assessed. RESULTS: Among the 400 women, 65 (16.3%) had ≥1 abnormality: higher TSH was found in 10.3%, lower FT(4) in 2% and positive TPO-Ab in 8.3%. Fifty-one women were examined and followed up. Levo-T(4) treatment was initiated in 49 women for autoimmune thyroiditis (in 42), hypothyroidism (in 34) or both (in 27). Only 22 (45%) of 49 treated women fulfilled ≥1 high-risk criterion: most commonly family history (31%), history of miscarriage or preterm delivery (14%) and personal history (8%). CONCLUSIONS: Over half (55%) of pregnant women with abnormalities suggestive of autoimmune thyroiditis and/or hypothyroidism would be missed if only those with high-risk criteria were examined. A more extensive screening of thyroid autoimmunity and dysfunction seems warranted.

The contribution of gastric emptying scintigraphy to the treatment of obesity with gastric bandage--preliminary results.

INTRODUCTION: Gastric banding for morbid obesity is among the least mutilating of procedures used in bariatric surgery and is classified as a restrictive surgical method. Although it is widespread, so far, however the mechanism responsible has not been fully explained. METHODS AND RESULTS: The authors present the preliminary results from scintigraphic examination of the evacuation ability of the stomach using food labeled with (99m)Tc-colloid in six obese patients with a gastric bandage. This initial study showed that the functionality of the bandage demonstrated as a significant drop in body weight, is connected with slower evacuation of the stomach. However, the use of adjustable bandages would have significantly slowed and restricted the passage of food through the cardia of the stomach. CONCLUSIONS: Since it can be extremely difficult to adequately objectively determine the functionality of gastric bandages, evaluating the gastric emptying scintigraphy may be useful in fulfilling this purpose.

Contrast-enhanced magnetic resonance and thallium scintigraphy in the detection of myocardial viability: a prospective comparative study.

The aim of the present study was to prospectively compare contrast-enhanced magnetic resonance imaging (CE-MRI) with single-photon emission tomography using (201)Thallium chloride (SPECT Tl) in the detection of myocardial viability. Patients with chronic coronary artery disease and systolic dysfunction defined by an ejection fraction (EF)