Mahmoud El-Desouki

Tl-201 thyroid imaging in differentiating benign from malignant thyroid nodules

To evaluate the value of Tl-201 thyroid imaging in differentiating benign from malignant thyroid nodules, 58 patients with histologically proven thyroid masses were studied. The nature of the thyroid tumor was initially assessed by Tc-99m scans. Early and delayed Tl-201 thyroid imaging were performed in all patients, and thallium uptake and clearance in the cold nodules were assessed visually. Of the 20 patients with histologically proven malignant nodules, 19 showed increased Tl-201 activity in both the early and delayed images, indicating a sensitivity of 95%. On the other hand, 35 out of the 38 patients with benign nodules showed no increased thallium activity in the nodules on the delayed images, indicating a specificity of 92%. When early thallium images were analyzed separately, the sensitivity was 100% but the specificity was only 37%. By combining early and delayed Tl-201 images, differentiation between benign and malignant cold nodules is feasible. False-positive and false-negative cases will be discussed.

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 Downs 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.

Features of hepatic cavernous hemangioma on planar and SPECT Tc-99m-labeled red blood cell scintigraphy

PURPOSE To determine the value and diagnostic accuracy of planar and SPECT Tc-99m-labeled red blood cell (Tc-99m RBC) scintigraphy in the investigation of suspected hepatic cavernous hemangioma as found on ultrasound. PATIENTS AND METHODS One hundred patients, 89 women (89%) and 11 men (11%), between 22 and 67 years old (mean age, 38 years) were evaluated for liver masses found on abdominal ultrasound. All the patients had previous Tc-99m RBC scintigraphy. The size of the lesions ranged from 1 to 9 cm. The final diagnosis was reached through cytologic biopsy, or histopathologic tests (or all of these). RESULTS One hundred thirty lesions were found. With regard to the distribution of the lesions, 116 (89%) were single; 14 (3%) were multiple, with 118 (91%) in the right lobe and 12 (9%) in the left lobe; 83 (64%) were posterior; and 47 (36%) were anterior. With respect to the pattern of radioactivity fill-in, 86 (66%) lesions were typical and 44 (34%) were atypical. The results of Tc-99m RBC scintigraphy showed sensitivity, specificity, and positive and negative predictive and accuracy values of 97%, 83%, 98%, 77%, and 96% respectively. The use of SPECT improved the sensitivity value by 11% for lesions of 1 to 2 cm. CONCLUSIONS Tc-99m RBC scintigraphy is the noninvasive technique most helpful in the diagnosis of hepatic hemangioma, especially in those at risk for lesion rupture or bleeding. SPECT should be performed whenever planar imaging fails to show the lesion by 2 hours. The use of ultrasound should precede scintigraphy for two important reasons: the size and the location of the lesion. Location of the lesion (anterior or posterior) is important for optimal gamma camera acquisition parameters. Lesions less than 1 cm are cannot be detected because they are beyond the limit of spatial resolution of the gamma camera we used.

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: Incidence, imaging, feasability, and difficulties of a nationwide program.

A pilot project was carried out in Riyadh to study the incidence and pattern of congenital hypothyroidism (CH) among newborn delivered at the Ministry of Health (MOH) hospitals. Cord blood was assayed for thyroid stimulating hormone (TSH). For affected infants, Tc-99m pertechnetate thyroid scintigraphy and perchlorate discharge test (PDT) using I(123) were performed to determine the caused of congenital hypothyroidism. Fifteen affected newborns were diagnosed among 40,000 newborns screened giving an incidence of 1:2666. Tc-99m thyroid scan revealed athyreosis in five infants; the thyroid gland was ectopic in eight and thyroid in two infants. In eight infants thyroid tissue was visualized, PDT was performed and the test was positive in seven cases (two eutopic and five ectopic). We concluded that the incidence of CH was higher compared with other parts of the world. Thyroid scintigraphy has a primary role in the evaluation of infants with congenital hypothyroidism and should be part of the protocol for the screening program. As early initiation of thyroxine therapy will prevent neurological and physical handicaps of the disease, the decision was made to have a nationwide screening program established in Saudi Arabia. The organization and difficulties of the screening program are being discussed.

Neonatal screening for congenital hypothyroidism in Saudi Arabia: results of screening the first 1 million newborns

Abstract Introduction : Since the initiation of pilot screening programs to detect congenital hypothyroidism (CH) in 1972, newborn screening has become routine in the developed world. A national screening program for CH was established in Saudi Arabia in November, 1989. Methods: The program utilizes cord serum thyroid stimulating hormone (TSH), tested by the Delfia method, supplemented when necessary with thyroxine (T4) assay, also by the Delfia method. TSH values above 60 mU/l alone were considered suggestive of CH and initiated recall of the infant. TSH values of 30–60 mU/l initiated T4 measurement. If the latter was below 80 nmol/l, the infant was also recalled. Results: Between November 1989 and April 1995, a total of 1007 350 infants were screened. The mean recall rate was 0.18% (range 0.05–0.3%). Of those, 306 infants were confirmed to have CH, indicating an incidence for CH in Saudi Arabia of 1:3292. However, a regional variation in incidence was noted. Of all the infants with congenital hypothyroidism who were adequately studied, 47.5% were found to have ectopic thyroid glands, 31.7% eutopic glands with increased 99m Tc uptake and 20.8% athyreotic. The mean age at the time of recall was 19.4 days (range 2–130). The average cost of screening was US S3.20 per specimen. Discussion: Several of the organizational and administrative difficulties which were encountered during the operation were discussed and solved at regional levels and during the annual general meetings.

Hashimoto's thyroiditis presenting as hot and cold nodules.

A case of Hashimotos thyroiditis is presented. I-123 thyroid scintigraphy demonstrated a hot nodule in the left lobe and a cold nodule in the right, which was well visualized by TI-201 imaging. This unusual scintigraphic appearance is demonstrated, and its possible explanation discussed.

Contribution of ventilation and perfusion lung imaging to the management of patients with bronchiectasis

Sixty patients were studied with ventilation-perfusion (V-P) lung scans for suspected bronchlectasis. Bronchography showed bronchlectatic changes in 51 patients. Lobar and segmental matched defects were seen on V-P scans in 53 patients, of which only 46 were true positives (sensitivity 90%). V-P lung scans showed the site and extent of bronchlectatic lesions; 48 (72.7%) in the left lung and 18 (27.3%) in the right lung. Detection of associated chronic obstructive airway disease by V-P scans in 17 patients had prognostic value in postsurgery recovery time and improvement of symptoms. This may be a potential new application to the routine use of V-P lung scan in the presurgery work-up of patients with bronchlectasis. Our results showed that bronchography should not be performed on patients with preserved lung perfusion.

Congenital hypothyroidism: Clinical and laboratory characteristics in infants detected by neonatal screening.

A pilot cord serum thyroid-stimulating hormone (TSH) screening program for congenital hypothyroidism began in December 1988 at the Ministry of Health Maternity Hospitals in Riyadh. Out of 40,000 infants screened, 15 infants with congenital hypothyroidism have been detected. Of these, five had athyreosis, eight with ectopic thyroid glands, interestingly five of which had positive perchlorate discharge test suggestive of organification defects, and two had normally located glands with perchlorate discharge test suggestive of organification defects. The female to male ratio was 1.5:1. The clinical characteristics in our cases were not different from that previously reported. Although there was no significant difference in the mean cord T4 values among the different groups, the mean T4 values at recall in the aplastic group is significantly (P<0.001) lower than the cord results, (60.3 versus 15.3) and that is of recall for the ectopic group (15.3 versus 47.0). There was no significant difference in the mean TSH among the different groups in the cord and recall samples. The skeletal maturation was more delayed in the athyrotic group. The mean age at the time of recall was 17.8 days (range 6 to 64) and the mean age at the start of therapy was 20 days (range 8 to 64).

Uncommon scintigraphic findings of multiple hepatic hemangiomas.

Tc-99m labeled red blood cell scintigraphy is a valuable, noninvasive technique for differentiating hepatic hemangioma from other lesions by demonstrating a “perfusion blood pool mismatch.” The characteristic finding on dynamic CT scan of peripheral and subsequent central enhancement is not usually seen on Tc-99m RBC angiography, probably due to rapid mixing and dilution of the radionuclide and low resolution of the gamma camera. A case of multiple hepatic hemangioma is presented in which Tc-99m RBC dynamic angiography demonstrated peripheral enhancement with subsequent central filling. In addition, delayed static images showed more hepatic lesions.