Pilar Orellana

Assessing the need for nuclear cardiology and other advanced cardiac imaging modalities in the developing world

BackgroundIn 2005, 80% of cardiovascular disease (CVD) deaths occurred in low- to middle-income countries (i.e., developing nations). Cardiovascular imaging, such as myocardial perfusion SPECT, is one method that may be applied to detect and foster improved detection of at-risk patients. This document will review the availability and utilization for nuclear cardiology procedures worldwide and propose strategies to devise regional centers of excellence to achieve quality imaging around the world.MethodsAs a means to establish the current state of nuclear cardiology, International Atomic Energy Agency member and non-member states were queried as to annual utilization of nuclear cardiology procedures. Other sources for imaging statistics included data from medical societies (American Society of Nuclear Cardiology, European Society of Cardiology, and the European Association of Nuclear Medicine) and nuclear cardiology working groups within several nations. Utilization was calculated by dividing annual procedural volume by 2007 population statistics (/100,000) and categorized as high (>1,000/100,000), moderate-high (250-999/100,000), moderate (100-249/100,000), low-moderate (50-99/100,000) and low (<50/100,000).ResultsHigh nuclear cardiology utilization was reported in the United States, Canada, and Israel. Most Western European countries, Australia, and Japan reported moderate-high utilization. With the exception of Argentina, Brazil, Colombia and Uruguay, South America had low usage. This was also noted across Eastern Europe, Russia, and Asia. Utilization patterns generally mirrored each country’s gross domestic product. However, nuclear cardiology utilization was higher for developing countries neighboring moderate-high “user” countries (e.g., Algeria and Egypt); perhaps the result of accessible high-quality training programs.ConclusionsWorldwide utilization patterns for nuclear cardiology vary substantially and may be influenced by physician access to training and education programs. Development of regional training centers of excellence can guide utilization of nuclear cardiology through the application of guideline- and appropriateness-driven testing, training, continuing education, and quality assurance programs aiding developing nations to confront the epidemics of CVD.

Current Status of Nuclear Medicine Practice in Latin America and the Caribbean

The practice of nuclear medicine (NM) in the Latin American and Caribbean region has experienced important growth in the last decade. However, there is great heterogeneity among countries regarding the availability of technology and human resources. According to data collected through June 2014 by the International Atomic Energy Agency (IAEA), the total number of γ cameras in the region is 1,231, with an average of 2.16 per million inhabitants. Over 90% of the equipment is SPECT cameras; 7.6% of which have hybrid technology. There are 161 operating PET or PET/CT cameras in 12 member states, representing a rate of 0.3 per million people. Most NM centers belong to the private health system and are in capitals or major cities. Only 4 countries have the capability of assembling 99Mo–99mTc generators, and 2 countries produce 99mTc from nuclear reactors. Cold kits are produced in some countries, and therapeutic agents are mostly imported from outside the region. There are 35 operative cyclotrons. In relation to human resources: there is 1 physician per γ camera, 1.6 technologists per γ camera, 0.1 medical physicist per center, and approximately 0.1 radiochemist or radiopharmacist per center. Nearly 94% of the procedures are diagnostic. PET studies represent about 4% of the total. The future of NM in the Latin American and Caribbean region is promising, with great potential and possibilities. Some of the most important factors driving the region toward greater homogeneity in the availability and application of NM, and bridging the gaps between countries, are clinician awareness of the importance of NM in managing diseases prevalent in the region, increased building of capacity, continuous and strong support from international organizations such as the IAEA through national and regional projects, and strong public–private partnerships and government commitment.

Gastroduodenal artery aneurysm detected by radionuclide studies.

A patient with gastroduodenal artery aneurysm detected with Tc-99m scintiangiography is described. Liver and hepatobiliary imaging were also performed on the patient. Ultrasound examination, arteriography, and surgical exploration were carried out. The value of radionuclide studies in leading to the proper diagnosis is emphasized.

Relationship between mechanical and metabolic dyssynchrony with left bundle branch block: evaluation by 18-fluorodeoxyglucose positron emission tomography in patients with non-ischemic heart failure.

BACKGROUND Ventricular dyssynchrony is a common finding in patients with heart failure (HF), especially in the presence of conduction delays. The loss of ventricular synchrony leads to progressive impairment of contractile function, which may be explained in part by segmental abnormalities of myocardial metabolism. However, the association of these metabolic disarrangements with parameters of ventricular dyssynchrony and electrocardiography (ECG) findings has not yet been studied. METHODS Our aim was to determine the correlation between the presence of left bundle branch block (LBBB) with left ventricular (LV) mechanical synchrony assessed by multiple-gated acquisition scan (MUGA) and with patterns of 18-fluorodeoxyglucose (18FDG) uptake in patients with non-ischemic heart failure. Twenty-two patients with non-ischemic cardiomyopathy, LV ejection fraction (LVEF) ≤45% and New York Heart Association (NYHA) Functional Class II or III symptoms under standard medical therapy were included, along with 10 healthy controls matched for age and gender. A 12-lead ECG was obtained to measure the length of the QRS. Mechanical LV synchrony was assessed by MUGA using phase analysis. All patients and controls underwent positron emission tomography with 18FDG to determine the distribution of myocardial glucose uptake. The standard deviation of peak (18)FDG uptake was used as an index of metabolic heterogeneity. Students t-test and Pearsons correlation were used for statistical analysis. RESULTS The mean age of the patients with HF was 54 ± 12 years and 72% were male. The length of the QRS was 129 ± 31 milliseconds and LBBB was present in 9 patients. Patients with HF had decreased LV 18FDG uptake compared with controls (7.56 ± 3.36 vs. 11.63 ± 4.55 standard uptake value; p = 0.03). The length of the QRS interval correlated significantly with glucose uptake heterogeneity (r = 0.62; p = 0.002) and mechanical dyssynchrony (r = 0.63; p = 0.006). HF patients with LBBB showed marked glucose uptake heterogeneity compared with HF patients without LBBB (41.4 ± 10 vs 34.7 ± 4.9 ml/100 g/min, respectively; p = 0.01). CONCLUSIONS Patients with non-ischemic heart failure exhibit a global decrease in myocardial glucose uptake. Within this group, subjects who also have LBBB exhibit a marked heterogeneity in segmental glucose uptake, which directly correlates with QRS duration.

Tiroides lingual como causa de disfagia: Caso clínico

We report an 11 year-old boy who presented with difficulty in swallowing without symptoms of hypothyroidism. The physical examination revealed a mass at the base of the tongue. The thyroid hormone profile showed a primary hypothyroidism (a serum TSH of 10.8 IU/mL with normal-low thyroxin of 6.0 microg/dL and low triiodothyronine of 57.8 ng/dL). Antithyroid antibodies were negative. The fiberoptic endoscopy showed a reddish mass, without evidence of haemorrhage or ulceration, confirmed as a well circumscribed, hypodense mass in the base of the tongue by computed tomography of the oropharynx and neck. Tc-99-pertechnetate scanning showed an abnormal area of uptake at the base of the tongue and no uptake in the normal thyroid location, concordant with an ectopic lingual thyroid gland. Levothyroxine in a suppressive dose was started that resulted in a reduction of the size of the mass and disappearance of dysphagia.

Association of adrenal medullar and cortical nodular hyperplasia: a report of two cases with clinical and morpho-functional considerations.

Arterial hypertension of adrenal etiology is mainly attributed to primary hyperaldosteronism. However, subtle expressions of hyperadrenergic or glucocorticoid excess can also generate arterial hypertension. The present report describes two hypertensive patients cataloged as resistant essential hypertensives, in whom adrenal masses were found incidentally, who highlight the need to recognize these tenuous clinical or laboratory presentations. Case 1 was a 50-yr-old female with hyperadrenergic hypertension associated to a left adrenal node, normal cortisol and aldosterone:renin ratio, marginally increased urinary normetanephrine, and a positive 131I MIBG radioisotope scan. Adrenalectomy normalized blood pressure and urinary metanephrines. Pathology showed a hyperplastic adrenal medulla associated to a multinodular cortical hyperplasia. Case 2 was a 62-yr-old female with progressive hypertension, a slight Cushing phenotype, non-suppressible hypercortisolism, normal urinary metanephrines, and bilateral adrenal nodes. Bilateral adrenalectomy and subsequent replacement normalized blood pressure and phenotypic stigmata. Pathology demonstrated bilateral cortical multinodular hyperplasia and medullary hyperplasia. The clinical study in both patients was negative for MEN. The apparently rare association of cortical and medullary lesions presented by both patients is probably overlooked in routine pathology exams, but should be meticulously searched since the crosstalk between the adrenal cortex and medulla may prompt dual abnormalities.

Single-parameter spin-pumping in driven metallic rings with spin-orbit coupling

We consider the generation of a pure spin-current at zero bias voltage with a single time-dependent potential. To such end we study a device made of a mesoscopic ring connected to electrodes and clarify the interplay between a magnetic flux, spin-orbit coupling, and non-adiabatic driving in the production of a spin and electrical current. By using Floquet theory, we show that the generated spin to charge current ratio can be controlled by tuning the spin-orbit coupling.

Enfermedad de Basedow Graves en pacientes pediátricos

Graves-Basedow disease in pediatric patients Objective: Determine differences in the epidemiology, clinical features and diagnosis of Graves-Basedow disease (GBD) in prepubertal and pubertal patients. Method: Retrospective study analyzing medical records of 38 patients with GBD at Pontificia Universidad Catolica de Chile between 1992-2007. Statistical analysis was performed with non parametric test of Mann-Whitney U and proportions difference with Fisher Test (SPSS 10.0 for Windows and Graphpad Prism 4). Results: 21 patients were prepubertal and 17 were pubertal, with ages between 3 and 15,9 years. There were more girls than boys in both groups (5:2 and 15:2, respectively; p = 0.2). The most common clinical presentations were diffuse goiter, hyperactivity, frequent bowel movements, insomnia and heat intolerance. The prepubertal group had a taller stature (+2.4 SDS) compared with the pubertal group (+0.2 SDS; p = 0.03) and the most frequent ocular manifestation was exophthalmus in both groups. Conclusions: We did not find any differences in the clinical presentations of Graves-Basedow disease among prepubertal and pubertal patients. Neuropsychiatric symptoms such as hyperactivity and insomnia, together with tall stature are common features in children with GBD. (Key words: Hyperthyroidism, thyroid, Graves-Basedow, autoinmunity, hyperactivity). Rev Chil Pediatr 2008; 79 (1): 26-35

Hiperinsulinismo congénito del recién nacido. A propósito de un caso clínico

Congenital hyperinsulinism (CH) is the most frequent cause of persistent hypoglycemia in the newborn and it is characterized by an inappropriately elevated insulin level in presence of hypoglycemia. Initial management is medical treatment, but if it fails, partial pancreatectomy is the surgical procedure of choice. OBJECTIVE To report a case of a newborn with CH to aware on this condition and update its multidisciplinary management. CASE REPORT The case of a full term newborn with severe symptomatic hypoglycemia unresponsive to medical treatment is reported . Ultrasonography and abdominal MRI were normal, Gallium 68 PET/CT showed uptake in the body of the pancreas. Laparoscopic corporocaudal pancreatectomy was performed. The patient resolved hypoglycemia and was discharged without incidents. Genetic study was consistent with focal CH, confirmed later by biopsy. DISCUSSION This case report exposes the clinical presentation of CH and its diagnosis. It emphasizes on the surgical treatment and the advantages of minimally invasive technique.Congenital hyperinsulinism (CH) is the most frequent cause of persistent hypoglycemia in the newborn and it is characterized by an inappropriately elevated insulin level in presence of hypoglycemia. Initial management is medical treatment, but if it fails, partial pancreatectomy is the surgical procedure of choice. Objective : To report a case of a newborn with CH to aware on this condition and update its multidisciplinary management. Case report: The case of a full term newborn with severe symptomatic hypoglycemia unresponsive to medical treatment is reported. Ultrasonography and abdominal MRI were normal, Gallium 68 PET/CT showed uptake in the body of the pancreas. Laparoscopic corporocaudal pancreatectomy was performed. The patient resolved hypoglycemia and was discharged without incidents. Genetic study was consistent with focal CH, confirmed later by biopsy. Discussion: This case report exposes the clinical presentation of CH and its diagnosis. It emphasizes on the surgical treatment and the advantages of minimally invasive technique.

Metabolismo energético del corazón y sus proyecciones en el tratamiento de la insuficiencia cardíaca

It is unknown why heart failure progresses even when patients are treated with the best therapy available. Evidences suggest that heart failure progression is due to loss of neurohumoral blockade in advanced stages of the disease and to alterations in myocardial metabolism induced, in part, by this neurohumoral activation. Alterations in cardiac energy metabolism, especially those related to substrate utilization and insulin resistance, reduce the efficiency of energy production, causing a heart energy reserve deficit. These events play a basic role in heart failure progression. Therefore, modulation of cardiac metabolism has arisen as a promissory therapy in the treatment of heart failure. This review describes myocardial energy metabolism, evaluates the role of impaired energy metabolism in heart failure progression and describes new therapies for heart failure involving metabolic intervention.