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Object: The gradient fields generated during magnetic resonance imaging (MRI) procedures have the potential to induce electrical current on implanted endocardial leads. Whether this current can result in undesired cardiac stimulation is unknown., Materials and Methods: This paper provides a detailed description of how to construct an optically coupled sensor for the measurement of gradient-field-induced currents into endocardial leads. The system is based on a microcontroller that works as analog-to-digital converter and sends the current signal acquired from the lead to an optical high-speed, light-emitting diode transmitter. A plastic fiber guides the light outside the MRI chamber to a photodiode receiver and then to an acquisition board connected to a PC laptop., Results: The performance of the system has been characterized in terms of power consumption (8 mA on average), sampling frequency (20.5 kHz), measurement range (-12.8 to 10.3 mA) and resolution (22.6 µA). Results inside a 3 T MRI scanner are also presented., Conclusions: The detailed description of the current sensor could permit more standardized study of MRI gradient current induction in pacemaker systems. Results show the potential of gradient currents to affect the pacemaker capability of triggering a heartbeat, by modifying the overall energy delivered by the stimulator.

Background: No data are available about the risk of thyroid disturbance after exposure to low-dose radiation due to the use of cardiac catheterization in the first years of life., Aim: To determine the risk of functional and morphological thyroid abnormalities in a homogeneous cohort of patients who underwent diagnostic low-dose radiation for heart catheterization during the first 18 months of life., Subjects and Methods: Fifty-five patients, submitted to cardiac catheterization during the first 18 months of life, underwent evaluation of the thyroid function and structure after a median period of 13 yr since the first radiation exposure. Sixty-eight unexposed controls matched for age and sex, underwent the same protocol. Twenty-two patients were then re-evaluated after a median period of 22 yr., Results: Thyroid function resulted normal in both patients and controls. The prevalence of small thyroid nodules and inhomogeneous structures in ultrasound study was not augmented in irradiated patients compared to controls. No thyroid tumors or reduced thyroid volume were observed., Conclusions: Neither functional nor morphological disorders of the thyroid gland were demonstrated after a period up to 24 yr in patients exposed to diagnostic ionizing radiation for cardiac catheterization during the first 18 months of life.

Objective: Pancreatic neuroendocrine cancer is a rare, indolent malignancy with no effective systemic therapy currently available. This population-based analysis evaluated the hypothesis that long-term survival benefit is greater with aggressive, rather than limited, surgical therapy., Methods: Non-functional pancreatic neuroendocrine carcinoma (NF-pNEC) cases diagnosed from 1973 to 2004 were retrieved from the SEER database., Results: A total of 2,158 patients with NF-pNEC were identified, representing 2% of all pancreatic malignancies. The annual incidence increased from 1.4 to 3.0 per million during the study period. On average, tumors measured 59 +/- 35 mm (median 50), and age at diagnosis was 59 +/- 15 years; 29% of patients were younger than 50. Nodal (44%) and systemic metastases (60%) were common. Overall the 5-, 10-, and 20-year survival rates were 33%, 17%, and 10%, respectively. Removal of the primary tumor significantly prolonged survival in the entire cohort (median 1.2 vs. 8.4 years; p < 0.001) and among those with metastases (median 1.0 vs. 4.8 years; p < 0.001). No survival difference was seen between enucleation and resection of the primary tumor (median 10.2 versus 9.2 years, p = 0.456)., Conclusion: This study suggests that surgical therapy improves survival among patients with localized, as well as metastatic, NF-pNEC. Enucleation may be oncologically equivalent to resection.

The magnetic resonance (MR) identification of pituitary hyperintensity in the posterior part of the sella has been the most striking recent finding contributing to the diagnosis of "idiopathic" and permanent GH deficiency (GHD). Moreover, advancements in DNA technology have shed new light on the study of the genetic causes of hypopituitarism. Abnormalities in two genes, the GH-N encoding the GH and the GHRH receptor (GHRH-R), have been identified, while mutations in five other gene-encoding transcription factors such as Pit-1, Prop-1, Hesx-1, Lhx-3 and Lhx-4 involved in anterior pituitary development, have also been described. MR imaging shows marked differences in pituitary morphology indicating different GHD etiologies and different prognoses. Ectopic posterior pituitary is a specific marker of permanent GHD. These patients do not have Pit-1, Prop-1, or Lhx-3 mutations and should be carefully monitored for evolving pituitary hormone defects, though they do not require GH re-evaluation in adulthood; selected cases may have Hesx-1 or Lhx-4 mutations. MR evidence of normal or small anterior pituitary gland, enlarged empty sella, pituitary hyperplasia and/or intrasellar or suprasellar mass when associated with combined pituitary hormone deficiency call for molecular analysis of Pit-1, Prop-1, Hesx-1, or Lhx-3. Limitation of neck rotation and Chiari-I malformation may suggest Lhx-3 or Lhx-4 mutations (exceedingly rare). In "idiopathic" isolated GHD, evidence of normal anterior or small anterior pituitary size with normal location of posterior pituitary and normal connection between the hypothalamus and pituitary gland is suggestive of "transitory" or false positive GHD; patients with such characteristics should be re-evaluated well before reaching adult height. In selected cases, anterior pituitary height that is 2 SD below age-adjusted normal pituitary height could be suggestive of GHRH-R gene defect; it is worth pointing out that normal pituitary MR together with severe GHD has been observed, though rarely, in subjects with a genetic origin of GHD.