Inter-observer reproducibility of relative 99Tcm-DMSA uptake.

99Tcm-DMSA planar images of 49 randomly selected patients (10 adults, 39 children) were sent to 15 physicians at various centres in Belgium. They were asked to calculate, using their own routine program, the relative uptake (expressed as a percentage) of each kidney. The data were sent on disks formatted so that they could be read by all participants, using their own computer systems. For each scan, the inter-observer variability was expressed using the maximum difference and the standard deviation of left renal uptake. Left renal uptake measured by the 15 observers in the 49 patients was 29.0-72.0% (mean +/- s = 49.8 +/- 6.4%). The maximum differences in left renal uptake ranged between 1.7% and 12.0% (4.5 +/- 2.6%); however, the maximum difference did not exceed 8% in about 90% of the patients. The standard deviations of the individual left renal uptake were between 0.6 and 3.9 (1.3 +/- 0.8). The standard deviations were significantly higher in adults (mean standard deviation = 2.05) than in children (mean standard deviation = 1.12) (P < 0.001); this was probably related to the high background observed in three adults with severe renal impairment. Indeed there was a significant correlation (P < 0.001) between the standard deviation and both the signal-to-noise ratio and the degree of asymmetry between the right and left kidneys. The differences between right and left kidney uptake were systematically lower for some observers, suggesting an influence of the calculation programs.

A multicenter trial on interobserver reproducibility in reporting on 99mTc-DMSA planar scintigraphy: a Belgian survey.

UNLABELLED: Conflicting opinions have been expressed regarding reproducibility in 99mTc-dimercaptosuccinic acid (DMSA) planar renal image interpretation. The purpose of this investigation was to determine the level of interobserver variability among a large group of Belgian nuclear medicine physicians who evaluated a randomly selected series of DMSA planar scintigraphic examinations performed on children and adults. METHODS: All Belgian nuclear medicine centers (n = 82) were invited to participate in a reproducibility study on 99mTc-DMSA scintigraphy. 99mTc-DMSA scans obtained on 10 adults and 40 children were randomly selected from the databases of 2 hospitals. Those participating in this investigation (65 centers = 79%) received a series of computer disks containing 50 99mTc-DMSA studies. To avoid potential problems related to unfamiliar display, the disks were formatted to be interpretable using the participants' own computer systems. Each participant was then free to use his or her usual display (hard copies, contrast enhancement, color scale, gray scale, and so forth). For each kidney, the observers had to choose between the following answers: normal, abnormal, equivocal, and lack of quality. RESULTS: Forty-two responses were obtained from a wide variety of institutions and from observers with different levels of experience in interpreting 99mTc-DMSA scintigraphy. Altogether, the following data were obtained: 60.8% normal, 25.2% abnormal, 7.0% equivocal, and 3.2% lack of quality. The median percentage of agreement (overall reproducibility) for the 42 observers was 92%. When the results of all 42 observers were compared, the median agreements on normality and abnormality were 93.5% and 90.5%, respectively. In a small number (n = 4) of kidneys, reproducibility was poor and ranged from 51% to 70%. Except for 2 outliers, all observers had almost the same level of performance. CONCLUSION: A large number of Belgian nuclear medicine physicians participated in evaluating a large randomly selected sample of 99mTc-DMSA studies, and excellent interobserver agreement was found.

[Use of 131 iodine for the treatment of hyperthyroidism in adults]. / Utilisation de l'iode 131 pour le traitement des hyperthyroïdies chez l'adulte.

The authors report on their experience with the treatment of hyperthyroidism using radioiodine (RI) over a period of 15 years in 516 patients. RI dosimetry was calculated from thyroid 24 hr uptake and weight, using linearly increasing RI doses (from 40 to 100 microCi/g) with increasing thyroid weight (between 10 and 100 g) for both diffuse (D) and multinodular (MN) toxic goiters. For solitary toxic (ST) nodules, a fixed dose of 250 microCi/g was used. In severe hyperthyroidism, antithyroid drugs (ATD) and KI (15 mg/d) were added 24 hours after RI and given during 1-4 months and 21 days, respectively. Combining RI + ATD/KI therapy allowed for a reduction of RI recirculation and release from the gland and also for more rapid return to a euthyroid status. The results showed that 88% of patients with ST, 68% with D, and 55% with MN were cured with a single dose of RI. Furthermore, the incidence of late hypothyroidism was relatively low, reaching 7% in ST, 36% in D, and 28% in MN after a follow-up period of fifteen years. Annual follow-up, however, showed that an additional 2.7% of patients (3.5% of D; 1.6% of MN; 2.4% of ST) exhibited--per year--an exaggerated TSH response to TRH even though these patients remained clinically and biochemically euthyroid (normal circulating basal hormones and TSH levels). In conclusion, 1) low doses RI combined with ATD/KI yielded a high success rate: less than 30% of patients required more than 1 dose and only 30% became hypothyroid after prolonged follow-up; 2) abnormalities of TRH test were not infrequent in patients with D and MN goiters, as well as ST nodules, thereby fully justifying the need for careful and prolonged follow-up of all hyperthyroid patients receiving RI therapy.

Radionuclide imaging in primary permanent congenital hypothyroidism.

Thyroid scintigraphy was performed in 69 consecutive infants with permanent primary congenital hypothyroidism (CH) detected by systematic neonatal thyroid screening using a rectilinear scanner or a gamma camera 15 minutes after the intravenous injection of 250 microCi Tc-99m sodium pertechnetate, immediately after the infants were fed. Immobilization of the infant in a supine position with the neck in hyperextension was achieved by a vacuum cushion without any sedation. Thyroid scintigraphy showed thyroid ectopia in 43 of the 69 CH infants, thyroid agenesis in 19, and goiter in the last 7 infants, respectively. The images were easily interpretable in all cases, even in very small ectopic glands in the lingual area, as there was no interference with extra-thyroidal uptake of the tracer, especially by the salivary glands. Our experience indicates that thyroid scintigraphy in the CH newborns can be performed immediately at the time of diagnosis of CH without technical difficulties. As thyroid scintigraphy is the only procedure allowing the distinction between thyroid agenesis and ectopia, and as the neurointellectual prognosis might be lower in the former than in the latter situation, thyroid scintigraphy in CH newborns contributes not only to the diagnosis but also the prognosis of the disorder.

[Isotopic method in the demonstration of diaphragmatic defects in a case of pleural effusion associated with cirrhosis: apropos of a case]. / Mise en évidence par méthode isotopique de défects diaphragmatiques en cas d'épanchement pleural associé à une cirrhose: à propos d'un cas.

A 62-year-old woman presented with massive right-sided hydrothorax associated with cirrhosis of the liver. Chest scintigraphy after intraperitoneal injection of labelled tracer showed movement of the tracer from the peritoneal to the pleural cavity. Medical therapy and thoracocentesis were successful in this case.

Radioiodine therapy in voluminous multinodular non-toxic goitre.

Large doses of radioiodine were administered since 1969 to 15 euthyroid patients with compressive voluminous goitres. A decrease in goitre size was observed in all patients (between 15 and 63%, average 39%). Maximal effect on goitre size was attained rapidly, partially already after less than one year and was almost maximal after 24 to 30 months. No significant local adverse reactions were observed; no patient required steroid administration. Hypothyroidism followed radioiodine administration in 30% of the patients after 2 years; after 8 years, all those who had survived were hypothyroid, requiring substitution therapy. In all patients there was a marked improvement in compression symptoms. The use of radioactive iodine therapy constitutes an alternative to surgery in selected patients with large compressive goitres in whom surgery is contraindicated because of age or other medical conditions.

Cold thyroid nodules in childhood: is surgery always necessary?

In children who present with a cold thyroid nodule the current recommendation is that surgery immediately be performed in view of the high probability of thyroid cancer. Because the incidence of thyroid cancer in children may be decreasing and because extensive experience has been gained in adults with thyroid echography and fine-needle aspiration cytology, we evaluated three consecutive children with cold thyroid nodules by means of these non-surgical techniques. The diagnoses were: thyroid cancer in one patient, thyroid abscess in one and haemorrhagic cyst of the thyroid in one. In the latter two patients, fine-needle aspiration was both diagnostic and therapeutic. We conclude that thyroid echography and fine-needle aspiration of thyroid nodules deserve more extensive evaluation in the paediatric age group.

Abnormalities of esophageal transit in patients with sporadic nontoxic goitre.

Esophageal transit (E.T.) was investigated in 122 consecutive euthyroid patients with scintigraphically proven goitre, and compared to 26 control subjects. E.T. was quantified using the 81mKr transit time, a highly sensitive technique capable of detecting even minor E.T. disorders. Abnormal E.T. was observed in 39% of goitrous patients, while it was normal in all controls. Occurrence of delayed E.T. was not correlated with either goitre firmness, the presence of symptoms of neck discomfort, difficulties in swallowing, or nodularity. E.T. delay was more frequent and more severe with larger goitres. In addition, E.T. delay was significantly correlated with asymmetry and "low lying" goitres. In summary, the present studies are the first demonstration of frequent E.T. anomalies in goitrous patients. The data suggest that E.T. impairment could be mediated by two mechanisms: a direct compression effect in patients with large, asymmetrical, partially retrosternal goitres; and an indirect functional esophageal anomaly in patients with small goitres.

Quantitation of esophageal transit by means of 81mKr.

A method for quantifying esophageal transit by means of 81mKr is described. The principal advantage of 81mKr compared with 99mTc is its ultra-short half-life with its consequences on radiation dose and counting statistics. Factors which may influence the esophageal transit time such as body posture, volume of the tracer, and the nature of the tracer were studied. The reproducibility of the technique is quite good and its capacity to detect minor esophageal transit disorders is demonstrated.

[Fine-needle aspiration (F.N.A.) of thyroid cold nodules (author's transl)]. / Place de la ponction á l'aiguille fine (P.A.F.) dans le diagnostic clinique du nodule thyroïdien froid.

In a retrospective study of 100 patients operated on between 1974 and 1979 in our institution for thyroid cold nodules, an 8% incidence of thyroid cancer was found at surgery. Since 1979, F.N.A. was performed in 160 patients with thyroid cold nodules. Adequate cytological material was aspirated in 90% (144) of the cases; of those, a benign cytological lesion was diagnosed in 128 (89%) and suspicion of cancer in 16 (11%). To date fifty-one patients were operated: 41 with benign cytology and 10 with cancer suspicion; benignity was confirmed in 39/41 cases with benign cytology and malignity in 5/10 with suspect cytology. In conclusion, clinical diagnosis of thyroid cold nodules is greatly improved by the use of F.N.A. Despite the limitations of the technique, preoperative suspicion of cancer was increased 7-fold. Caution is recommended in the follow-up cases with benign cytology since, in these preliminary results, 2 false-negatives were found.