sodium-pertechnetate-tc-99m and potassium-perchlorate

At the molecular level, the uptake of radioiodine and pertechnetate is proportional to the expression of the thyroidal sodium/iodine symporter (NIS). Qualitative and quantitative scintigraphic evaluation of the thyroid is performed with a gamma camera fitted with an on-line computer system and enables determination of the iodine uptake or the technetium uptake (TCTU) as an iodine clearance equivalent. Despite new molecular genetic insights into congenital hypothyroidism, the iodine-123 or pertechnetate scan remains the most accurate test for the detection of ectopic thyroid tissue. Following the identification of specific mutations of the genes coding for the NIS, thyroid peroxidase and pendrin, the discharge test has lost its role in establishing the diagnosis of inherited dyshormonogenesis, but it is still of value in the assessment of defect severity. In PDS mutations the test can be used to establish the diagnosis of syndromic disease. Quantitative pertechnetate scintigraphy is the most sensitive and specific technique for the diagnosis and quantification of thyroid autonomy. The method has proved to be valuable in risk stratification of spontaneous or iodine-induced hyperthyroidism, in the estimation of the target volume prior to radioiodine therapy and in the evaluation of therapeutic success after definitive treatment. In iodine deficiency areas the thyroid scan remains indispensable for the functional characterisation of a thyroid nodule and is still a first-line diagnostic procedure in cases of suspected thyroid malignancy. This is especially of importance in patients with Graves' disease, among whom a relatively high prevalence of cancer has been found in cold thyroid nodules. While determination of the TCTU is without any value in the differentiation between autoimmune thyroiditis and Graves' disease in most cases, it is of substantial importance in the differentiation between hyperthyroid autoimmune thyroiditis and Graves' disease.

Topics: Adult; Child; Congenital Hypothyroidism; Gamma Cameras; Humans; Iodine Radioisotopes; Ion Channels; Ion Transport; Perchlorates; Potassium Compounds; Prognosis; Radionuclide Imaging; Radiopharmaceuticals; Sodium Pertechnetate Tc 99m; Symporters; Thyroid Diseases; Thyroid Function Tests; Thyroid Gland; Thyroid Neoplasms; Thyroid Nodule; Thyroiditis, Autoimmune; Ultrasonography

The diagnostic value of scintigraphy using a dual tracer and high-resolution neck ecotomography in the preoperative localisation of parathyroid enlargements was evaluated in a group of consecutive patients suffering from primary hyperparathyroidism (HPT) who were uniformly studied and subsequently operated by the same surgical team.. Scintigraphic imaging and high-resolution neck ecotomography were carried out in a single session on 143 patients. Scintigraphic imaging was performed using a dual tracer, 99mTc-pertechnetate/99mTc-MIBI), modified by the addition of potassium perchlorate (KCL04) to achieve a rapid washout of 99mTc04 from the thyroid and, consequently, to achieve good quality and rapid MIBI images. In a limited number of patients (21 cases) SPECT was also performed. Limited surgery was planned in patients with evidence of single parathyroid lesions and with normal thyroid parameters, in the form of either unilateral or with mini-invasive surgery (91 cases). Patients with eco-scintigraphic evidence of multiglandular parathyroid pathology or the coexistence of a nodular thyroid goitre, or in patients suffering from MEN or familial HPT, or lastly those with negative eco-scintigraphic results under-went more extensive surgery with bilateral exploration of the neck (52 cases). A single parathyroid lesion was diagnosed during surgery in 90 out of 91 patients undergoing planned unilateral or mini-invasive exploration of the neck. Therefore, in our experience, the predictive value of preoperative imaging as a mean of identifying single parathyroid lesions was 98.9% with a clear impact on the choice of conservative surgery. After the removal of the parathyroid to which preoperative imaging referred, it was only necessary in one patient to extend surgical exploration to the other side of the neck to remove another enlarged parathyroid owing to persistent high PTH.. The sensitivity of scintigraphy and high-resolution neck ecotomography in pa-tients with a single adenoma was 94% and 83.7% respectively, whereas it was 76.9% and 64.5% respectively in the group of patients with multiglandular pathology. It is worth underlining that in all 31 patients with associated nodular thyroid pathology, the evaluation of thyroid scintigraphic imaging using 99mTc04 and high-resolution neck ecotomography enabled the preoperative diagnosis of thyroid pathology, therefore guiding the surgeon towards more extensive surgery. SPECT enabled the parathyroid adenoma to be correctly localised in a deep site in 5 patients, in the neck in 3 cases and at the mediastinum in 2 patients, providing additional data that helped the surgeon to plan surgery.. In conclusion, in our experience: a) an integrated diagnostic approach based on scintigraphy 99mTc04 & KCLO4/MIBI and high-resolution neck ecotomography was an extremely accurate mean of identifying patients with single parathyroid lesions before surgery, enabling them to undergo limited surgery, b) scintigraphy with a dual tracer might be the elective methods for studying patients with HPT because it allows the contemporary diagnosis of possible thyroid diseases. This aspect is extremely important in geographical areas with a high predominance of nodular thyroid pathology, c) SPECT scintigraphic analysis may be useful in some patients with suspected parathyroid adenoma localised in a deep seat, allowing a more precise identification of the latter and better surgical planning.

Topics: Adenoma; Adult; Aged; Carcinoma; Female; Follow-Up Studies; Humans; Hyperparathyroidism; Male; Mediastinum; Middle Aged; Multiple Endocrine Neoplasia Type 1; Neck; Parathyroid Neoplasms; Parathyroidectomy; Perchlorates; Potassium Compounds; Radiopharmaceuticals; Sensitivity and Specificity; Sodium Pertechnetate Tc 99m; Technetium Tc 99m Sestamibi; Tomography, Emission-Computed, Single-Photon; Ultrasonography

A 52-year-old woman was hospitalized because of dyspnea and dysphagia. Thoracic computed tomography revealed a retrotracheal mass. Tc-99m pertechnetate scintigraphy showed intense accumulation of radioactivity corresponding to the mediastinal mass detected by computed tomography. Repeated Tc-99m pertechnetate scintigraphy performed after oral administration of potassium perchlorate (KCLO4) revealed complete disappearance of the radioactive accumulation in the mediastinum, suggesting that the retrotracheal mass was a retrosternal goiter. Subsequent surgical removal and analysis of the mass showed it was indeed a retrosternal goiter. This case highlights the importance of Tc-99m pertechnetate thyroid scintigraphy with and without KCLO4 administration as a simple, accurate, and cost-effective imaging method to diagnose retrosternal goiter.

Topics: Administration, Oral; Antithyroid Agents; Female; Follow-Up Studies; Goiter, Substernal; Humans; Middle Aged; Perchlorates; Potassium Compounds; Radionuclide Imaging; Radiopharmaceuticals; Sodium Pertechnetate Tc 99m; Tomography, X-Ray Computed

We set up a modified technetium-99m (Tc-99m) pertechnetate/Tc-99m MIBI (Tc-MIBI) subtraction scintigraphy for parathyroid imaging by introducing the use of potassium perchlorate (KCLO4). Initially, the effect of KCLO4 on technetium thyroid wash-out was evaluated in five healthy volunteers: 40-minute dynamic studies of the thyroid were obtained 20 minutes after the injection of technetium 150 MBq (4 mCi), both in baseline conditions and after the oral administration of 400 mg KCLO4. After an average latency time of 10.5 minutes, KCLO4 administration resulted in fast and relevant technetium thyroid wash-out with a mean half-time of 16.2 minutes (the half-time was 142.8 minutes in baseline conditions), and a 40-minute reduction of thyroid activity of 78% (it was 14% in baseline conditions). Based on these findings, a new Tc-MIBI subtraction procedure was established as follows: 1) 150 MBq technetium (4 mCi) injection; 2) 400 mg KCLO4 administered orally; 3) patient neck immobilization; 4) acquisition of a 5-minute technetium thyroid scan; 5) 500 MBq MIBI (13.5 mCi) injection; 6) acquisition of a sequence of seven MIBI images, each lasting 5 minutes; and 7) processing (image realignment when necessary, background subtraction, normalization of MIBI images to the maximum pixel count of the technetium image, and subtraction of the technetium image from the MIBI images). In addition, high-resolution neck ultrasound (US) was performed in all cases on the same day as the scintigraphic evaluation. Eighteen consecutive patients with primary hyperparathyroidism were enrolled in the study. Tc-MIBI scintigraphy revealed a single adenoma in all cases and US showed this finding in 15 of 18 cases (83.3%). Furthermore, in three patients, a thyroid nodule associated with hyperparathyroidism was detected by technetium thyroid scans and neck US. In all patients, the parathyroid adenoma was easily identified on both the 20- to 40-minute MIBI and subtracted (MIBI-Tc) images. Regarding the scintigraphic parameters, no difference was found between parathyroid adenomas located in the region of the thyroid bed or in ectopic sites and in parathyroid adenomas with a retrothyroid location. Surgical findings confirmed the presence of a single parathyroid adenoma in all cases. In the three patients with a concomitant thyroid nodule, thyroid lobectomy was performed. These preliminary data suggest that 1) double-tracer subtraction scintigraphy, combined with neck US, appears to be the pref

Topics: Adenoma; Female; Humans; Hyperparathyroidism; Male; Middle Aged; Parathyroid Glands; Parathyroid Neoplasms; Perchlorates; Potassium Compounds; Radionuclide Imaging; Radiopharmaceuticals; Sodium Pertechnetate Tc 99m; Subtraction Technique; Technetium Tc 99m Sestamibi; Time Factors

Thyroid gland ectopy is the most common cause in infants with congenital hypothyroidism (CH). Its association with iodine organification defect, as suggested by positive perchlorate discharge test (PDT) has been reported. However, whether such an association represents a true or transient defect has not yet been determined. This finding has an important clinical, epidemiological, and genetic implications.. To determine the natural history of iodine organification defect in patients with CH caused by thyroid ectopy detected by neonatal screening.. Prospective longitudinal study.. King Khalid University Hospital, Riyadh, Saudi Arabia.. PDT was performed, at the time of diagnosis and follow-up, in infants who showed an enlarged ectopic thyroid gland with a Tc-99m pertechnetate uptake of 2% or more.. Of 115 neonates with ectopic thyroid glands, 19 showed an enlarged gland with Tc-99m uptake ranging from 2 to 3.2%. Perchlorate discharge test was performed in 13 of these and was consistent with iodine organification defect in nine. Repeated PDT in seven patients showed normal values.. The results of the authors' study indicate the transient nature of the iodine organification defect and suggest that a delay in the developmental of synthetic mechanisms occur in the dysgenetic glands.

Topics: Choristoma; Congenital Hypothyroidism; Female; Humans; Hypothyroidism; Infant, Newborn; Male; Neonatal Screening; Perchlorates; Potassium Compounds; Prospective Studies; Radionuclide Imaging; Sodium Pertechnetate Tc 99m; Thyroid Function Tests; Thyroid Gland; Tongue Diseases

Quantitative thyroid scanning using low doses of technetium-99m sodium pertechnetate was performed on 147 infants (55 males and 92 females) with congenital hypothyroidism detected through the national neonatal screening programme. Thirty-two (21.8%) were athyrotic, while 62 (42.2%) had an ectopic thyroid and 53 (36%) had a eutopic gland with increased 99mTc uptake (mean 17%; range, 5%-38%). The perchlorate discharge test (PDT) was performed in nine of the infants with ectopic glands and 15 with eutopic glands; the findings were consistent with an organification defect in 22 cases (seven ectopic and 15 eutopic). Thyroid scintigraphy and PDT can add useful aetiological, genetic and prognostic information in the clinical evaluation of infants with congenital hypothyroidism detected by neonatal screening.

Topics: Choristoma; Congenital Hypothyroidism; Female; Humans; Hypothyroidism; Infant, Newborn; Iodine Radioisotopes; Male; Neonatal Screening; Perchlorates; Potassium Compounds; Radionuclide Imaging; Sodium Pertechnetate Tc 99m; Thyroid Function Tests; Thyroid Gland

Abnormal localization of 99mTc pertechnetate was detected in the choroid plexus of patients with renal insufficiency despite the administration of potassium perchlorate. This was found in 8 of 21 studies on patients on conservative medical treatment, in 35 of 41 studies in patients on hemodialysis, in 12 of 22 studies in renal transplant recipients, and in 1 of 5 with acute renal insufficiency, but not in any of 33 persons free of renal disease. Abnormal retention of pertechnetate was also observed in the salivary glands of 21 renal patients. The increased localization of 99mTc pertechnetate could not be related to high blood levels of radioactivity, altered protein binding, increased erythrocyte labeling or to impaired gastrointestinal absorption of potassium perchlorate. It is proposed that this finding represents a manifestation of choroid plexus dysfunction resulting in altered handling of anions by this organ. A possible relation to neurological disease in chronic renal insufficiency is suggested.

Topics: Choroid Plexus; Creatinine; Humans; Kidney Diseases; Kidney Transplantation; Perchlorates; Potassium; Potassium Compounds; Radionuclide Imaging; Renal Dialysis; Salivary Glands; Sodium Pertechnetate Tc 99m; Technetium; Thyroid Gland

Topics: Erythrocytes; Heart; Humans; Image Enhancement; Isotope Labeling; Perchlorates; Potassium; Potassium Compounds; Radionuclide Imaging; Sodium Pertechnetate Tc 99m; Technetium; Tin Polyphosphates

The pharmacokinetic behavior of pertechnetate in normal subjects has been studied. Each received 400 mg of potassium perchlorate 30 min before pertechnetate injection. Timed blood samples were collected and counted. The time-activity curves for whole blood and plasma could both be fitted to an open two-compartment model of the form 3 comes from 1 in equilibrium with 2, where Compartment 1 refers to the vascular pool, Compartment 2 to the perivascular pool, and Compartment 3 to the urine. The pharmacokinetic state equation is given by: leads to X = -KX. Rate constants determined were: k21 = 1.47 hr-1; k12 = 3.11 hr-1; k01 = 0.137 hr-1. The rate constants were the same for the whole-blood and plasma time-activity curves.

Topics: Drug Interactions; Humans; Injections, Intravenous; Kinetics; Perchlorates; Potassium; Potassium Compounds; Sodium Pertechnetate Tc 99m; Technetium; Time Factors