Effect of prolonged fasting and low molecular weight heparin or warfarin therapies on 2-deoxy-2-[18F]-fluoro-D-glucose PET cardiac uptake.

BACKGROUND: Whether anticoagulants other than unfractionated heparin are able to suppress cardiac PET uptake of 2-deoxy-2-[18F]-fluoro-D-glucose (18F-FDG) is unknown. METHODS: One-hundred-seventy-four patients without history and clinical evidence of cardiac dysfunction and/or coronary heart disease underwent a 18F-FDG PET/CT study. All patients were studied with a >12-hours fasting and divided into 2 groups: group-1 without anticoagulant therapy (n:75); group-2 patients on low molecular weight heparin (n:60) or warfarin therapy (n:39). Cardiac 18F-FDG uptake was estimated qualitatively using a 4-point scale and semiquantitatively as total LV glycolysis (LVG) and metabolic volume (MV), drawing isocontour volume of interest (VOI) including the whole LV. RESULTS: Qualitatively, LV 18-FDG uptake was scored 0 or 1, indicating a good suppression, in 10/75 (13%) patients of group-1 and 77/99 (78%) of group-2 (p < .001). Semiquantitatively, patients of group-1 showed higher values of 18-FDG uptake than patients of group-2, assessed as LVG (802,649 ± 468,442 vs 198,989 ± 261,439, p < .0001) or MV (219 ± 77 vs 57 ± 48 cm3, p < .0001). Subanalysis for anticoagulant drugs showed similar results. CONCLUSIONS: Prolonged fasting combined to anticoagulants other than unfractionated heparin is able to minimize glucose cardiac metabolism. Our data confirm previous observation on the possibility to influence the metabolic pattern of the heart before the PET scan and broadens the spectrum of pharmacological options.

Effect of iodinated contrast medium on thyroid function: a study in children undergoing cardiac computed tomography.

BACKGROUND: Few studies, and with conflicting results, have evaluated the potential effects of iodinated contrast media on children's thyroid function. OBJECTIVE: To investigate the effects of iodinated contrast medium on thyroid function in neonates, infants and young children with congenital heart disease undergoing cardiac computed tomography (CT). MATERIALS AND METHODS: We retrospectively evaluated 10 neonates (group 1) and 23 infants and young children (group 2) without thyroid or renal disease for serum levels of thyroid-stimulating hormone, free triiodothyronine and free thyroxine before contrast-enhanced cardiac CT, 48 h after CT and at discharge from the hospital. Cardiac CT was performed with intravenous administration of 1.14±0.17 mL/kg of body weight of iopromide (containing 370 mg of iodine/mL). RESULTS: Group 1 had a reduction of thyroid-stimulating hormone from baseline to 48 h post injection (P=0.002). Group 2 had a reduction of thyroid-stimulating hormone median levels from baseline to 48 h post injection and an increase from 48 h to discharge (P=0.0005 and P=0.0001, respectively). CONCLUSION: Intravenous iodinated contrast medium in children with congenital heart disease caused transient thyroid-stimulating hormone decrease 48 h after CT, with thyroid-stimulating hormone returning to normal range at discharge.

Hypothyroidism in Patients with Down Syndrome: Prevalence and Association with Congenital Heart Defects.

This population-based study aimed to assess the prevalence of congenital hypothyroidism (CH) and overt hypothyroidism (OH) and their association with congenital heart defects (CHDs) in patients with Down syndrome (DS). The population included all live births residing in Tuscany (Italy) diagnosed with DS recorded in the Registry of Congenital Defects and in the Registry of Rare Diseases of Tuscany in the years 2003-2017. The prevalence of CH and OH in DS patients was calculated by sex and by period. The association of CH and OH with CHDs in DS patients was assessed using multivariate logistic regression. The cohort included 228 subjects. The prevalence of CH and OH was 11.4% (95%CI: 7.4-16.7%) and 12.7% (95%CI: 8.5-12.3%), respectively, with no significant difference by sex. A significant increase in the prevalence of CH (p < 0.0001) was found in the years 2010-2017 compared to the previous period, and among preterm infants (p = 0.009). The presence of CH was associated with a higher prevalence of CHDs (adjusted OR = 2.24, p = 0.082). A significant association between ventricular septal defects (VSDs) and the occurrence of OH (adjusted OR = 3.07, p = 0.025) was also observed. This study confirmed the higher prevalence of both CH and OH in DS compared to the general population. Furthermore, the risk of association between DS and CHDs was higher in the presence of CH, while VSDs are associated with OH, providing relevant insights into the epidemiology of hypothyroidism in DS and associated anomalies.

Prevalence of thyroid dysfunction and effect of contrast medium on thyroid metabolism in cardiac patients undergoing coronary angiography.

BACKGROUND: Iodinated contrast media (CM) may influence thyroid function. Precautions are generally taken in patients with hyperthyroidism, even if subclinical, whereas the risks in patients with hypothyroidism or low triiodothyronine (T3) syndrome are not considered as appreciable. PURPOSE: To assess the presence and type of thyroid dysfunction in patients admitted for coronary angiography (CA), to assess the concentration of free-iodide in five non-ionic CM, and to evaluate changes in thyroid function after CA in patients with low T3 syndrome. MATERIAL AND METHODS: We measured free T3, free thyroxine (T4), and thyroid-stimulating hormone (TSH) in 1752 consecutive patients prior to CA and free-iodide in five non-ionic CM. Urinary free-iodide before and 24 h after CA, and thyroid hormone profile 48 h after CA were also made in 17 patients with low T3 syndrome. Patients were followed up for an average duration of 63.5 months. RESULTS: The patients were divided into four groups: euthyroidism (60%), low T3 syndrome (28%), hypothyroidism (10%), and hyperthyroidism (2%). The free-iodide resulted far below the recommended limit of 50 µg/mL in all tested CM. In low T3 syndrome, 24-h free-iodide increased after CA from 99.9 ± 63 ug to 12276 ± 9285 ug (P < 0.0001). A reduction in TSH (4.97 ± 1.1 vs. 4.17 ± 1.1 mUI/mL, P < 0.01) and free T3 (1.44 ± 0.2 vs. 1.25 ± 0.3 pg/mL, P < 0.01), with an increase in free T4 (11.3 ± 2.9 vs. 12.5 ± 3.4 pg/dL, P < 0.001), was found. Patients with functional thyroid disease in the follow-up had a significant lower rate survival compared to euthyroid patients (90.7 vs. 82.2%, P < 0.00001). CONCLUSION: Thyroid dysfunction is frequent in patients who perform a CA, and low T3 syndrome is the predominant feature. The administration of contrast medium may further compromise the thyroid function.

Does subclinical hypothyroidism affect cardiac pump performance? Evidence from a magnetic resonance imaging study.

OBJECTIVES: We sought to assess the effects of subclinical hypothyroidism (SHT) on the cardiac volumes and function. BACKGROUND: The cardiovascular system is one of the principal targets of thyroid hormones. Subclinical hypothyroidism is a common disorder that may represent "early" thyroid failure. METHODS: Thyroid profile was evaluated in 30 females with SHT and 20 matched control subjects. Left ventricular end-diastolic volume (EDV) and end-systolic volume (ESV), stroke volume (SV), cardiac index (CI), and systemic vascular resistance (SVR) were calculated by cardiac magnetic resonance (CMR). Regional greatest systolic lengthening (E1) and greatest systolic shortening (E2) were calculated by tagging CMR. RESULTS: EDV was lower in SHT than in controls (64.3 +/- 8.7 ml/m(2) vs. 81.4 +/- 11.3 ml/m(2), p < 0.001), as well as SV [corrected] (38.9 +/- 7.5 ml/m(2) vs. 52.5 +/- 6.1 ml/m(2), p < 0.001) and CI (2.6 +/- 0.5 l/[min.m(2)] vs. 3.7 +/- 0.4 l/[min.m(2)], p < 0.001). SVR [corrected] was higher in SHT (12.5 +/- 2.5 mm Hg.min/[l.m(2)] vs. 8.6 +/- 1.1 mm Hg.min/[l.m(2)], p = 0.003). The E1 was higher in controls than in SHT at the basal (p = 0.007), equatorial (p = 0.05), and apical (p = 0.008) levels, as well as E2 at the equatorial (p = 0.001) and apical (p = 0.001) levels. All parameters normalized after replacement therapy. A negative correlation between TSH and EDV (p < 0.001), SV (p < 0.001), CI (p < 0.001), and E1 at the apical level (p < 0.001) and a positive correlation between TSH and SVR (p < 0.001) and E2 at the apical level (p < 0.001) were found. CONCLUSIONS: Subclinical hypothyroidism significantly decreased cardiac preload, whereas it increased afterload with a consequent reduction in SV and cardiac output. Replacement therapy fully normalized the hemodynamic alterations.

From the bench to the bedside. Galectin-3 immunodetection for improving the preoperative diagnosis of the follicular thyroid nodules.

The authors discuss the principal aspects concerning the preoperative characterization of thyroid nodules, in particular those with follicular histology, and illustrate the potential clinical impact of a new diagnostic test-method, named "galectin-3 thyrotest", which is based on the immunodetection of galectin-3 molecule in cytological specimens derived from thyroid nodular lesions. This diagnostic test method, which consistently improves the accuracy of conventional cytology, has been recently validated in a large international multicenter study and is going to impact hardly the clinical management of patients bearing thyroid nodular diseases. The rationale of this new diagnostic approach, the possibility to improve its performance in selected cases by using large needle aspiration biopsy (LNAB) together with technical and operative details are presented and discussed.

Is recombinant human TSH as effective as thyroid hormone withdrawal in the detection and treatment of metastatic differentiated thyroid cancer?

Evaluation of: Van Nostr D, Khorjekav GR, O'Neil J et al. Recombinant human thyroid-stimulating hormone versus thyroid hormone withdrawal in the identification of metastasis in differentiated thyroid cancer with 131I planar whole body imaging and 124I PET. J. Nucl. Med 53(3), 359-362 (2012). In a recent article, Van Nostrand et al. compared two methods of patient preparation, that is, recombinant human thyroid-stimulating hormone and thyroid hormone withdrawal, for the detection of metastasis in patients previously treated for differentiated thyroid cancer, using both 131I whole-body imaging and 124I positron emission tomography. The major finding of this prospective study was that the number of patients and the number of foci for patient positive at 131I whole-body imaging and 124I PET performed after thyroid hormone withdrawal was significantly higher when compared with that related to patients prepared with recombinant human thyroid-stimulating hormone.

Acute effect of TSH on oxygenation state and volume of erythrocytes from subjects thyroidectomized for differentiated thyroid carcinoma.

We previously reported the presence in the membrane erythrocyte of a TSH receptor (TSHR), a G-protein coupled receptor, which responds to TSH with increased cAMP level. Since there is evidence for a role of G protein receptors as oxygen sensor(s) implicated in cell volume regulation, we hypothesized that erythrocyte TSHR, by TSH stimulation, could modify the erythrocyte volume and the oxygenation state of erythrocytes. We determined the effect of TSH on the gas analysis in 35 thyroidectomized patients for stage I differentiated thyroid cancer enrolled for recombinant human thyroid-stimulating hormone (rhTSH) test during chronic treatment with synthetic l-thyroxine. Moreover, we explored the influence of TSH on the shape of erythrocytes. Venous blood-gas analysis before and after TSH were determined with a pH/blood gas electrolyte and 682 CO-Oxymeter. In a subgroup of subjects (n=10), the isolated red blood cells (RBC) were analyzed by flow cytometry for morphological changes. After TSH stimulation, we found a significant decrease in PCO(2) (P<0.001), an increase in pH (P<0.01) and an increase of % O(2)-Hb (P<0.05) and pO(2) (P<0.05). By flow cytometry, the erythrocytes after TSH showed a significant enrichment on the mean number in the selected region R1 corresponding to bigger volumes (P<0.05, n=10). Finally, by contrast phase microscopy, when the cell area was measured, a mean increased volume was observed in erythrocytes after TSH compared to the basal before TSH (P<0.05). In conclusion, our results indicate that acute stimulation of TSH by rhTSH modifies the oxygenation state and volume of erythrocyte.

Clinical feasibility of two-step streptavidin/111In-biotin scintigraphy in patients with suspected vertebral osteomyelitis.

PURPOSE: Streptavidin accumulates at sites of inflammation and infection as a result of increased capillary permeability. In addition to being utilised by bacteria for their own growth, biotin forms a stable, high-affinity non-covalent complex with avidin. The objective of this investigation was to determine the diagnostic performance of two-step streptavidin/111In-biotin imaging for evaluating patients with suspected vertebral osteomyelitis. METHODS: We evaluated 55 consecutive patients with suspected vertebral osteomyelitis (34 women and 21 men aged 27-86 years), within 2 weeks after the onset of clinical symptoms. Thirty-two of the patients underwent magnetic resonance imaging (MRI) and 24, computed tomography (CT). DTPA-conjugated biotin was radiolabelled by incubating 500 microg of DTPA-biotin with 111 MBq of 111In-chloride. Two-step scintigraphy was performed by first infusing 3 mg streptavidin intravenously, followed 4 h later by 111In-biotin. Imaging was begun 60 min later. RESULTS: Streptavidin/111In-biotin scintigraphy was positive in 32/34 patients with spinal infection (94.12% sensitivity). The study was negative in 19/21 patients without infection (95.24% specificity). The corresponding results for MRI and CT were 54.17% and 35.29% (sensitivity), and 75% and 57.14% (specificity), respectively. All statistical parameters of diagnostic performance (Youden's J index, kappa measure of agreement with correct classification, accuracy, sensitivity, specificity, positive likelihood and negative likelihood) were clearly better for streptavidin/111In-biotin scintigraphy than for either MRI or CT. CONCLUSION: Streptavidin/111In-biotin scintigraphy is highly sensitive and specific for detecting vertebral osteomyelitis in the first 2 weeks after the onset of clinical symptoms, and is potentially very useful for guiding clinical decisions on instituting appropriate therapy.