Roy Moncayo

Brain perfusion scintigraphy with 99mTc-HMPAO or 99mTc-ECD and 123I-beta-CIT single-photon emission tomography in dementia of the Alzheimer-type and diffuse Lewy body disease.

Dementia of the Alzheimer-type (DAT) is characterized by progressive cognitive decline, variably combined with frontal lobe release signs, parkinsonian symptoms and myoclonus. The features of diffuse Lewy body disease (DLBD), the second most common cause of degenerative dementia, include progressive cognitive deterioration, often associated with levodopa-responsive parkinsonism, fluctuations of cognitive and motor functions, psychotic symptoms (visual and auditory hallucinations, depression), hypersensitivity to neuroleptics and orthostatic hypotension. A recent report suggests that positron emission tomography studies in patients with degenerative dementia may be useful in the differential diagnosis of DAT and DLBD. However, the diagnostic role of single-photon emission tomography (SPET) studies remains to be established. The aim of this study was therefore to evaluate regional cerebral perfusion [with either technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO) or99mTc-ethyl cysteinate dimer (99mTc-ECD) SPET] and striatal dopamine transporter density [using iodine-123 2β-carboxymethoxy-3β-[4-iodophenyl]tropane (123I-β-CIT) SPET] in patients with DAT and DLBD. Six patients with probable DAT and seven patients with probable DLBD were studied. Blinded qualitative assessment by four independent raters of99mTc-HMPAO or99mTc-ECD SPET studies revealed bilateral temporal and/or parietal hypoperfusion in all DAT patients. There was additional frontal hypoperfusion in two patients and occipital hypoperfusion in one patient. In the DLBD group, regional cerebral perfusion had a different pattern. In addition to temporoparietal hypoperfusion there was occipital hypoperfusion resembling a horseshoe defect in six of seven patients. In the DAT group, the mean 3-h striatal/cerebellar ratio of123I-β-CIT binding was 2.5±0.4, with an increase to 5.5±1.1 18 h after tracer injection. In comparison, in the DLBD patients the mean 3-h striatal/cerebellar ratio of123I-β-CIT binding was significantly reduced to 1.7±0.3, with a modest increase to 2.1±0.4 18 h after tracer injection (P<0.05, Scheffe test, ANOVA). These results suggest that99mTc-HMPAO or99mTc-ECD and123I-β-CIT SPET may contribute to the differential diagnosis between DAT and DLBD, showing different perfusion patterns and more severe impairment of dopamine transporter function in DLBD than in DAT.

131I/123I-metaiodobenzylguanidine (mIBG) scintigraphy: procedure guidelines for tumour imaging.

The aim of this document is to provide general information about mIBG scintigraphy in cancer patients. The guidelines describe the mIBG scintigraphy protocol currently used in clinical routine, but do not include all existing procedures for neuroendocrine tumours. The guidelines should therefore not be taken as exclusive of other nuclear medicine modalities that can be used to obtain comparable results. It is important to remember that the resources and facilities available for patient care may vary from one country to another and from one medical institution to another. The present guidelines have been prepared for nuclear medicine physicians and intend to offer assistance in optimizing the diagnostic information that can currently be obtained from mIBG scintigraphy. The corresponding guidelines of the Society of Nuclear Medicine (SNM) and the Dosimetry, Therapy and Paediatric Committee of the EANM have been taken into consideration, and partially integrated into this text. The same has been done with the most relevant literature on this topic, and the final result has been discussed within a group of distinguished experts.

111In-pentetreotide scintigraphy: procedure guidelines for tumour imaging.

This document provides general information about somatostatin receptor scintigraphy with 111In-pentetreotide. This guideline should not be regarded as the only approach to visualise tumours expressing somatostatin receptors or as exclusive of other nuclear medicine procedures useful to obtain comparable results. The aim of this guideline is to assist nuclear medicine physicians in recommending, performing, reporting and interpreting the results of 111In-pentetreotide scintigraphy.

Pediatric reference intervals for thyroid hormone levels from birth to adulthood: a retrospective study

BackgroundAge- and sex-specific reference intervals are an important prerequisite for interpreting thyroid hormone measurements in children. However, only few studies have reported age- and sex-specific pediatric reference values for TSHbasal (TSH), free T3 (fT3), and free T4 (fT4) so far. Reference intervals are known to be method- and population-dependent. The aim of our study was to establish reference intervals for serum TSH, fT3, and fT4 from birth to 18 years and to assess sex differences.Methods2,194 thyroid hormone tests obtained from a hospital-based pediatric population were included into our retrospective analysis. Individuals with diagnoses or medications likely to affect thyroid function were primarily excluded, as well as the diagnostic groups, if different from the purely healthy subgroup (n = 414). Age groups were ranging from 1 day to 1 month, 1 – 12 months, and 1 – 5, 6 – 10, 11 – 14, and 15 – 18 years, respectively. Levels of fT3, fT4 and TSH were measured on Advia® Centaur™ automated immunoassay system.ResultsThe final sample size for reference data creation was 1,209 for TSH, 1,395 for fT3, and 1,229 for fT4. Median and 2.5/10/25/75/90/97.5 percentiles were calculated for each age group. Males had greater mean fT3 concentrations than females (p < 0.001). No sex-differences were found for TSH and fT4 between age-matched serum samples. Median concentrations of fT3, fT4 and TSH were greatest during the first month of life, followed by a continuous decline with age.ConclusionOur results corroborate those of previous studies showing that thyroid hormone levels change markedly during childhood, and that adult reference intervals are not universally applicable to children. Moreover, differences of our reference intervals compared to previous studies were observed, likely caused by different antibody characteristics of various analytical methods, different populations or undefined geographic covariates, e.g. iodine and selenium status.

Breast scintigraphy: procedure guidelines for tumour imaging

The purpose of this document is to provide general infor-mation about bone scintigraphy in oncology. Theseguidelines describe procedures currently in routine clini-cal use but should not be interpreted as excluding alterna-tive procedures also employed to obtain equivalent data.It must be remembered that the resources and facilitiesavailable to care for patients may vary from one countryto another and from one medical institution to another.This document has been prepared primarily for nuclearmedicine physicians and is intended to offer assistance inoptimising the diagnostic information that can currentlybe obtained from bone scintigraphy. The correspondingguidelines from the Society of Nuclear Medicine (SNM)have been taken into consideration, reviewed and partial-ly integrated into this text. In addition, the literature onthis topic has been reviewed and discussed by an interna-tional group of distinguished experts.

Thallium-201 gated single-photon emission tomography for the assessment of left ventricular ejection fraction and regional wall motion abnormalities in comparison with two-dimensional echocardiography

Abstract. Simultaneous assessment of myocardial perfusion and function by gated single-photon emission tomography (GS) after a single tracer injection provides incremental information and is feasible with technetium-99m sestamibi. The present study validated the use of GS with thallium-201 for the assessment of left ventricular ejection fraction (LVEF) and regional wall motion by comparison with two-dimensional (2D) echocardiography (echo), which has not been done before. After injection of 111 MBq 201Tl at peak bicycle exercise (n=55) or pharmacological stress (n=17), GS was acquired 15 (post stress) and 120 min post injection (rest) on a double-head camera. An automatic algorithm (QGS) was used for processing. Echo (Acuson Sequoia C256) was performed immediately after rest GS. LVEFs assessed by GS and echo were correlated. The overall and segmental sensitivity and specificity of GS for the detection of regional wall motion abnormalities (WMAs) were calculated, echo serving as the gold standard. Perfusion abnormalities were scored. The success rate of the automatic algorithm was 100%, and visually assessed image quality was good to excellent in 88% of cases. Post-stress and rest LVEF as assessed by GS were highly correlated (r=0.91). Good correlations were obtained between post-stress LVEF (GS) and rest LVEF (echo) and between rest LVEF (GS) and rest LVEF (echo) (r=0.76 and 0.86 respectively). In patients with a reduced LVEF of less than 50% (n=23), these correlations were even better (r=0.84 and 0.89 respectively). Regional wall motion abnormalities (WMAs) were identified by GS with high sensitivity and specificity (88%–100% and 82%–98% respectively) and were directly related to the extent and severity of stress as well as of resting perfusion defects. It is concluded that GS with 201Tl is a feasible and reliable tool for the evaluation of patients with compromised left ventricular function in the context of coronary artery disease, and thus improves diagnosis and prognostic stratification. Regional WMAs were identified with high diagnostic accuracy and the method may prove helpful for the detection of myocardial viability.

FDG-PET: procedure guidelines for tumour imaging

F]fluorodeoxyglucose positron emission tomography (FDG-PET) in oncology. These guidelinesdo not include all the existing procedures for FDG-PETbut describe only the most common FDG-PET protocolsused in the current clinical routine studies. For this rea-son, some techniques, such as dynamic tomographicstudies, and some instruments, such as gamma camerasfor coincidence imaging, are only touched upon. Theguidelines should therefore not be taken as inclusive ofall possible PET procedures or exclusive of other nuclearmedicine procedures useful to obtain comparable results.It should be remembered that the resources and the facil-ities available for patient care may vary from one coun-try to another and from one medical institution to an-other. The present guide has been prepared for nuclearmedicine physicians and is intended to offer assistance inoptimising the diagnostic information that can currentlybe obtained from FDG-PET imaging. The Guidelines ofthe Society of Nuclear Medicine (SNM), the ProceduresGuidelines for Brain Imaging Using FGD (EANM) andthe existing guidelines for PET of some European Soci-eties have been reviewed and integrated into the presenttext. The same has been done with the most relevant

Autoimmunity and the ovary

The ovary was first documented as a target of autoimmunity over three decades ago yet today the aetiology and pathogenesis of autoimmune-mediated premature ovarian failure (POF) are poorly understood. Here, Roy and Helga Moncayo provide a brief overview of human autoimmune-mediated POF and the animal models of POF. They propose a model for the development of the disease, highlighting the role of supraphysiological levels of gonadotropins in inducing selectively antigenic mature ovarian elements.

The role of selenium, vitamin C, and zinc in benign thyroid diseases and of selenium in malignant thyroid diseases: Low selenium levels are found in subacute and silent thyroiditis and in papillary and follicular carcinoma

BackgroundThyroid physiology is closely related to oxidative changes. The aim of this controlled study was to evaluate the levels of nutritional anti-oxidants such as vitamin C, zinc (Zn) and selenium (Se), and to investigate any association of them with parameters of thyroid function and pathology including benign and malignant thyroid diseases.MethodsThis controlled evaluation of Se included a total of 1401 subjects (1186 adults and 215 children) distributed as follows: control group (n = 687), benign thyroid disease (85 children and 465 adults); malignant thyroid disease (2 children and 79 adults). Clinical evaluation of patients with benign thyroid disease included sonography, scintigraphy, as well as the determination of fT3, fT4, TSH, thyroid antibodies levels, Se, Zn, and vitamin C. Besides the routine oncological parameters (TG, TSH, fT4, ultrasound) Se was also determined in the cases of malignant disease. The local control groups for the evaluation of Se levels were taken from a general practice (WOMED) as well as from healthy active athletes. Blood samples were collected between 8:00 and 10:30 a.m. All patients lived in Innsbruck. Statistical analysis was done using SPSS 14.0. The Ho stated that there should be no differences in the levels of antioxidants between controls and thyroid disease patients.ResultsAmong the thyroid disease patients neither vitamin C, nor Zn nor Se correlated with any of the following parameters: age, sex, BMI, body weight, thyroid scintigraphy, ultrasound pattern, thyroid function, or thyroid antibodies. The proportion of patients with benign thyroid diseases having analyte concentrations below external reference cut off levels were 8.7% of cases for vitamin C; 7.8% for Zn, and 20.3% for Se. Low Se levels in the control group were found in 12%. Se levels were significantly decreased in cases of sub-acute and silent thyroiditis (66.4 ± 23.1 μg/l and 59.3 ± 20.1 μg/l, respectively) as well as in follicular and papillary thyroid carcinoma. The mean Se level in the control group was 90.5 ± 20.8 μg/l.ConclusionThe H0 can be accepted for vitamin C and zinc levels whereas it has to be rejected for Se. Patients with benign or malignant thyroid diseases can present low Se levels as compared to controls. Low levels of vitamin C were found in all subgroups of patients.

Somatostatin receptor SPECT

Somatostatin is a peptide with a broad distribution in the nervous system and acts as a neurotransmitter in several organs, having a wide range of mainly inhibiting effects, such as the suppression of growth hormone release, as well as the inhibition of pancreatic and gastrointestinal hormone release. Five somatostatin receptor subtypes have been cloned and demonstrated to have an emphasized expression in all human tumours. In particular, type 2 receptors were identified as the most frequently represented on the surface of neuroendocrine tumour cells, providing the molecular basis for many clinical applications of somatostatin analogues. Towards the end of the 1980s, the in vivo demonstration of somatostatin receptors on the surface of some tumours raised interest in receptor imaging, and indeed the peptide receptor overexpression on tumour cells, as compared to normal tissues, constitutes the basis for molecular imaging of these tumours. This review intends to illustrate the development of single photon emission radiopharmaceuticals for the study of somatostatin receptors and their application in diagnostic imaging.