Franca Dicembrino

Predictive value of recombinant human TSH stimulation and neck ultrasonography in differentiated thyroid cancer patients.

BACKGROUND Serum thyroglobulin (Tg) stimulation by recombinant human TSH (rhTSH), in combination with neck ultrasonography (US), is an important tool in the first follow-up of differentiated epithelial cell thyroid carcinoma (DTC) patients. The objective of this study was to investigate if a second rhTSH stimulation, performed 2-3 years later, is of clinical utility in the follow-up of these patients. METHODS One hundred and one consecutive ambulatory DTC patients were studied. The great majority of them (89/101) were low-risk patients, being stage I or II at tumor node metastasis (TNM) staging classification. All study patients had been treated by surgery and radioiodine ablation, and exhibited, at first rhTSH follow-up, either undetectable Tg (<or=1 ng/mL) (rhTSH1-Tg-, n = 89 patients considered as free of disease) or low Tg (>1-5 ng/mL) (rhTSH1-Tg+, n = 12 patients considered with uncertain prognosis), with no US evidence of residual disease. In all patients, serum Tg measurement after a second rhTSH stimulation and neck US were performed. RESULTS At the second follow-up, all 89 rhTSH1-Tg-patients showed a negative US, and Tg became low positive only in one case, whereas it remained undetectable in the other patients. The overall negative predictive value of rhTSH1-Tg- was, then, 98.9%. Out of the remaining 12 patients (i.e., rhTSH1-Tg+ patients), 2 showed disease persistence/recurrence (with a positive predictive value of rhTSH1-Tg+ of 16.7%) and 6 became Tg-. CONCLUSIONS A second rhTSH stimulation is useless in DTC patients who were rhTSH-Tg and imaging negative at first follow-up, while it is suggested in patients with detectable, although low, rhTSH-Tg levels at first follow-up: in the absence of clinical or US evidence of disease persistence, these patients should not be retreated by radioiodine, but simply scheduled for a later rhTSH stimulation.

Considerations of brain death on a SPECT cerebral perfusion study.

Brain death imaging is often a diagnostic challenge. Cerebral angioscintigraphy is extensively used for this analysis, but this test does not allow the perfusion evaluation of the posterior fossa. The authors report a case in which a SPECT study showed persistence of blood frow in infratentorial structures with total absence of cerebral (supratentorial) perfusion. This finding excluded the diagnosis of brain death.

Age-related changes in the global skeletal uptake of technetium-99m methylene diphosphonate in healthy women.

A short-term evaluation of global skeletal uptake (GSU) of technetium-99m methylene diphosphonate (MDP) was performed in 40 healthy female subjects with a wide age range in order to investigate the clinical performance of the technique and to detect the age-related changes in bone turnover. The results obtained were compared with measurements of the main biochemical markers of skeletal metabolism. We found that GSU increases progressively with age, independently of concomitant changes in renal function; significant correlations with biochemical markers of bone formation were also found. Therefore, the method appears to provide useful information concerning the bone turnover rate, and is also applicable to elderly people owing to its simplicity.

Global skeletal uptake of 99mTc-methylene diphosphonate (GSU) in patients affected by endocrine diseases: Comparison with biochemical markers of bone turnover

Abstract: This study aimed to clinically validate the global skeletal uptake (GSU) of 99mTc-methylene diphosphonate (99mTc-MDP), and to compare it with a marker of bone formation (i.e. serum osteocalcin or OC) and an index of bone resorption (i.e. urinary deoxypyridinoline or U-DPD) in different endocrine disorders affecting the skeleton. We studied 29 female patients with thyrotoxicosis (TT), 27 with primary hyperparathyroidism (PHPT), 16 with acromegaly (AC), 15 with Cushing’s syndrome (CS), and altogether 110 healthy women matched for age, BMI and menstrual status. In all subjects total body digital scan images (TBDS) were acquired at 5 min and at 4 h after the administration of 99mTc-MDP; the whole body retention (WBR) of the tracer was measured by counting two identical sets of rectangular ROIs, and GSU was subsequently calculated by drawing an irregular ROI on 4 h TBDS images. Serum OC was assessed by IRMA and urinary DPD by fluorometric detection after reverse phase high pressure chromatography. In TT patients GSU (40.0 ± 5.1 vs 36.5 ± 4.8%), OC (19.1 ± 11.8 vs 7.1 ± 2.9 mg/l) and U-DPD (62.4 ± 42.7 vs 19.5 ± 5.3 pmol/pmol) were significantly (p<0.01) higher than in controls. PHPT patients showed GSU (47.2 ± 6.6 vs 37.8 ± 5.3%), OC (38.6 ± 40.9 vs 8.2 ± 2.5 mg/l), and U-DPD (55.0 ± 51.3 vs 21.9 ± 6.1 pmol/pmol) values significantly (p<0.001) higher than controls. In CS patients, GSU (39.6 ± 6.4 vs 32.7 ± 3.5%; p<0.01) and U-DPD (22.8 ± 8.4 vs 16.5 ± 2.7 pmol/pmol; p<0.05) were higher, whereas OC (3.6 ± 2.4 vs 5.2 ± 1.9 mg/l; p<0,05) was lower than in controls. In AC patients, GSU (34.9 ± 5.3 vs 35.2 ± 3.4%) did not differ significantly from controls, whereas OC (16.8 ± 8.8 vs 6.9 ± 2.9 mg/l; p<0.001) and U-DPD (30.9 ± 13.6 vs 21.0 ± 5.7 pmol/pmol; p<0.01) were higher. Stepwise multivariate linear regression analysis was performed with disease activity, creatinine clearance, age, and years since menopause as predictor variables and GSU or OC or U-DPD as dependent variables. The significant partial regression coefficients (r) were: in TT, free triiodothyronine (fT3) with GSU (r = 0.37; p<0.005), Ln OC (r = 0.30; p = NS), Ln U-DPD (r = 0.76; p<0.0001), respectively; in PHPT, PTH with GSU (r = 0.74; p<0.001), Ln OC (r = 0.50; p<0.05), Ln U-DPD (r = 0.64; p<0.001); in CS Ln urinary free cortisol with OC (r = −0.68; p<0.001) and U-DPD (r = 0.66; p<0.05). Our data suggest that GSU could represent a valuable clinical tool for evaluating bone turnover rate in PHPT, CS, TT but not in AC. The behavior of GSU and OC and U-DPD is non-uniform in disorders characterized by a marked uncoupling between bone formation and resorption.

False positive diagnosis on 131 iodine whole-body scintigraphy of differentiated thyroid cancers

Abstract131Iodine is used both to ablate any residual thyroid tissue or metastatic disease and to obtain whole-body diagnostic images after total thyroidectomy for differentiated thyroid cancer (DTC). Even though whole-body scan is highly accurate in showing thyroid residues as well as metastases of DTC, false positive results can be found, possibly leading to diagnostic errors and unnecessary treatments. This paper reviews the physiological and pathological processes involved as well as the strategy to recognize and rule out false positive radioiodine images.

Global skeletal uptake of technetium-99m methylene diphosphonate in female patients receiving suppressive doses of L-thyroxine for differentiated thyroid cancer.

Abstract. This study was carried out in order to investigate the possible detrimental effects on bone of levothyroxine (l-T4) suppressive therapy in female patients who had undergone surgery for differentiated thyroid cancer (DTC). Twenty female (14 premenopausal and 6 postmenopausal) patients receiving l-T4 suppressive therapy for DTC were studied. The sample was selected in such a way as to avoid factors influencing bone metabolism other than l-T4. All patients were monitored by sensitive thyroid-stimulating hormone, free triiodothyronine and free thyroxine assays throughout the follow-up. Nineteen healthy (12 premenopausal and 7 postmenopausal) matched women served as controls. In all subjects bone turnover was evaluated by the measurement of global skeletal uptake of technetium-99m methylene diphosphonate (GSU); bone mineral density (BMD) was measured by quantitative computed tomography at the lumbar spine (LS) and by dual-energy X-ray absorptiometry both at the LS and at three femoral sites: the femoral neck, Ward’s triangle and the greater trochanter. No significant difference was found in either GSU or BMD between patients (treated for an average period of 68 months) and controls in the whole sample or in any subgroup. Furthermore, no correlations were found between either GSU or BMD and the duration of therapy, daily doses of l-T4 or results of thyroid function tests. Our data show that carefully monitored l-T4 therapy does not influence skeletal turnover (directly reflected by GSU) or the bone density of the spine and femur.