Measurement of iodine-123 thyroid uptake using a gamma camera with LEAP collimator.

OBJECTIVE: This study compared the 123I thyroid uptake measurements obtained from a gamma camera fitted with a low-energy all-purpose (LEAP) collimator to those obtained from a thyroid uptake probe and gamma camera fitted with a pinhole (PH) collimator. METHODS: Thirty-one patients (27 female and 4 male patients) were studied for comparison between a probe and a gamma camera fitted with LEAP collimators. A different group of 25 patients (20 female and 5 male patients) were studied for comparison between LEAP and PH collimators. The patients were given 7.4-11 MBq (200-300 pCi) 123I capsules orally. Uptake with both the probe and the gamma camera was measured at 5 h and 24 h. The uptake measurements by these 3 methods were compared. RESULTS: Comparison of all the camera uptake values with the probe system correlated well with correlation coefficient values ranging from 0.912-0.988. The probe system yielded uptake ratios slightly higher than those measured by the gamma camera with LEAP collimator. Comparison between LEAP and PH uptake values resulted in a correlation coefficient of 0.979 for 5 h and 0.931 for 24 h uptake. CONCLUSION: Iodine-123 uptake with a gamma camera fitted with a LEAP collimator can accurately and consistantly be used to determine the thyroid uptake of 123I if proper ROIs are applied.

Familial occurrence of congenital hypothyroidism due to lingual thyroid gland.

Two sisters who presented with midline neck masses proved to be biochemically hypothyroid. Thyroid scintigraphy supplemented with perchlorate discharge testing showed lingual thyroid glands and ruled out the expected autosomal recessive organification defect. The related literature is reviewed.

Measurement of bone mineral density of the lumbar spine and femur in normal Saudi children and adolescents using dual x-ray absorptiometry.

Full text is available as a scanned copy of the original print version.

Osteoporosis in postmenopausal Saudi women using dual X-ray bone densitometry.

Full text is available as a scanned copy of the original print version.

Congenital anomalies in infants with congenital hypothyroidism: is it a coincidental or an associated finding?

During the period between December 1988 and February 1995, a total of 279,482 newborn infants were screened in the regional neonatal screening program for congenital hypothyroidism (CH) in Riyadh province, Saudi Arabia. Eighty-one infants were confirmed to have CH giving an incidence of 1 in 3,450. Variable congenital anomalies, other than those of the thyroid gland, were present in 16 (19.8%). The anomalies most frequently encountered were congenital heart defects (7), unclassified multiple congenital anomalies (5) and Down's syndrome (2). The results of our study confirm this association, and emphasize the need to search for such anomalies in infants born with CH. Nationwide studies, however, on birth defects in the general population and those associated with CH are still needed to help us understanding the role of local genetic and environmental factors.

Transient iodine organification defect in infants with ectopic thyroid glands.

BACKGROUND: 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. OBJECTIVE: To determine the natural history of iodine organification defect in patients with CH caused by thyroid ectopy detected by neonatal screening. DESIGN: Prospective longitudinal study. SETTING: King Khalid University Hospital, Riyadh, Saudi Arabia. PATIENTS AND METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Congenital hypothyroidism: increased incidence in Najran province, Saudi Arabia.

Neonatal screening for congenital hypothyroidism using cord serum thyroid-stimulating hormone (TSH) was initiated in Najran health region in September 1990. A total of 30810 newborn infants were screened by April 1995. Of the 24 infants with abnormal thyroid function tests on recall, 22 had permanent primary congenital hypothyroidism (incidence; 1:1400) and in two male siblings transient congenital hypothyroidism (incidence; 1:15400) was proved on follow-up. There was a significantly higher incidence of dyshormonogenesis. Eight (57 per cent) of the 14 infants who were adequately studied thyroid scan revealed ectopic glands with increased 99mTc uptake, while thyroid ectopy and aplasia were present only in three (22 per cent) infants each. Furthermore, goiter was evident clinically in two other patients.

Neonatal screening for congenital hypothyroidism in Riyadh: Analysis of six year's experience.

The regional screening program for congenital hypothyroidism (CH) in Riyadh Province was started as a pilot study in December 1988. By September 1990, the program covered all deliveries at the Ministry of Health (MOH) and King Saud University hospitals. The program utilizes cord serum thyroid-stimulating hormone (TSH) with a low recall rate of 0.1%. The average cost per specimen was SR 12 (US$ 3.20). Among 283,647 infants screened, 83 infants were confirmed to have CH (incidence 1:3417). In 17 infants, however, the diagnosis was not confirmed due to difficulties in recall. Eleven infants with cord serum TSH of more than 100 mU/L proved to be clinically and biochemically euthyroid at recall. Three of these were secondary to maternal proplthiouracil (PTU) therapy. The female to male ratio was 1.5:1. The majority of infants lacked clinical symptoms and signs of hypothyroidism. Thyroid scans showed the most common etiology to be thyroid ectopy (50%), followed by dyshormonogenesis (26%) and athyrosis (24%). Although there was no significant difference in the mean cord T4 values among the different groups, the mean T4 value at recall in the athyrotic group was significantly (P <0.001) lower than the cord results (14.8 versus 62.7) and that is of recall for the ectopic and dyshormonogenesis groups (14.8 versus 47.0 and 51.3 respectively0. There was bo significant difference in the mean TSH among the different groups in the cord and recall samples. Skeletal maturation was more delayed in the athyrotic group. The mean age at the time of recall was 16.4 days (range 4 to 64), and the mean age at the start of therapy was 17.8 days (range 5-64).