Acromegaly with empty sella syndrome.

SUMMARY: Acromegaly is a rare, chronic progressive disorder with characteristic clinical features caused by persistent hypersecretion of growth hormone (GH), mostly from a pituitary adenoma (95%). Occasionally, ectopic production of GH or growth hormone-releasing hormone (GHRH) with resultant GH hypersecretion may lead to acromegaly. Sometimes localizing the source of GH hypersecretion may prove difficult. Rarely, acromegaly has been found in patients with an empty sella (ES) secondary to prior pituitary radiation and/or surgery. However, acromegaly in patients with primary empty sella (PES) is exceeding rarely and has only been described in a few cases. We describe a 47-year-old male who presented with overt features of acromegaly (macroglossia, prognathism, increased hand and feet size). Biochemically, both the serum GH (21.6 µg/L) and insulin-like growth factor 1 (635 µg/L) were elevated. In addition, there was a paradoxical elevation of GH following a 75 g oral glucose load. Pituitary MRI demonstrated an ES. In order to exclude an ectopic source of GH hypersecretion, further biochemical tests and imaging were done, which were unremarkable. Notably, increased uptake in the sella turcica on the 68Gallium DOTATATE PET/CT confirmed the ES as the likely source of GH secretion. As no overt lesion was noted, medical treatment (octreotide acetate) was initiated with a good clinical and biochemical response. At his 3 month follow-up, he reported an improvement in symptoms (fatigue and headache), however he still complained of low libido. Due to a persistently low testosterone level at follow-up, a long-acting testosterone was initiated. His GH level normalised, and IGF-1 has significantly reduced. LEARNING POINTS: The commonest cause of acromegaly is due to GH hypersecretion from pituitary adenomas (95%). Acromegaly has rarely been found in patients with ES. It is important to exclude a past history suggestive of pituitary apoplexy. Extra-pituitary source of GH such as ectopic production of GHRH with resultant GH hypersecretion needs to be excluded. In such cases, since there is no resectable mass, medical therapy is the primary treatment option.

Evaluation of technetium-99m metastable nanocolloid as an imaging agent for performing milk scans.

OBJECTIVE: The aim of this study was to determine whether technetium-99m (Tc) nanocolloid was a suitable alternative tracer for carrying out milk scan studies in pediatric patients. PARTICIPANTS AND METHODS: Twenty-seven milk scans performed with Tc nanocolloid were retrospectively assessed for identification of significant esophageal hold-up, gastroesophageal reflux, pulmonary aspiration, and gastric emptying (GE). Scans were also assessed for liver, spleen, and bone marrow uptake. GE results were compared with those of 27 randomly selected normal GE studies carried out using Tc tin colloid. RESULTS: None of the studies had liver, spleen, or bone marrow uptake, and all studies were interpretable. Significant esophageal hold-up and gastroesophageal reflux was observed in 11 and 48% of the patients, respectively. Only one patient had evidence of pulmonary aspiration, and all patients had normal GE at 2 h after radiolabeled milk ingestion. The average rate of GE at 2 h was faster in the Tc nanocolloid group compared with the Tc tin colloid group (8.85% retained±8.96% vs. 15.48% retained±10.52%, P=0.016). CONCLUSION: Our findings show that Tc nanocolloid is technically a suitable alternative to Tc sulfur colloid for performing milk scans. However, we could not conclude with certainty on the comparison of the GE rates of Tc nanocolloid and Tc tin colloid. This was because of the variability in the two population groups as well as the fact that the milk that was used in each patient was individualized to the patient and was not standardized.

A prospective study comparing 99mTc-MIBI and 99mTc-MDP with 99mTc-DTPA for lung ventilation scintigraphy in pulmonary thromboembolism.

OBJECTIVE: The aim of the study was to assess the efficacy of technetium 99m-methyl diphosphonate (Tc-MDP) and technetium 99m-methoxyisobutylisonitrile (Tc-MIBI) as radioaerosol alternatives to technetium 99m-diethylenetriaminepentacetate (Tc-DTPA) in the evaluation of pulmonary thromboembolism, as the direct consequence of the possible outcome could be cost saving. PATIENTS AND METHODS: Patients referred to our institution from August 2015 to July 2017 for a ventilation-perfusion scan who fulfilled the inclusion criteria were enrolled into the study as participants. Each ventilation agent was used to ventilate 43 participants, making a total of 129 participants in the study. Images were assessed for quality and alveolar clearance qualitatively and semiquantitatively correspondingly by a nuclear medicine physician blinded to the agent used. RESULTS: Tc-MIBI had higher count rates than Tc-DTPA and Tc-MDP, with a statistically significant difference when compared with Tc-DTPA (P=0.021). Tc-MIBI clearly showed slower alveolar clearance when compared with the clearance of Tc-DTPA (P≤0.0001) and Tc-MDP (P≤0.001). In terms of image quality, Tc-MIBI generally had better quality images as compared with the other two radioaerosols, with a statistically significant difference when compared with Tc-DTPA (P=0.001). CONCLUSION: Tc-MIBI had superior image quality and slower alveolar clearance when compared with Tc-DTPA. Alongside Tc-MDP, these agents can replace Tc-DTPA whenever clinically and economically applicable.

Efficacy of full-fat milk and diluted lemon juice in reducing infra-cardiac activity of (99m)Tc sestamibi during myocardial perfusion imaging.

BACKGROUND: When using (99m)Tc sestamibi for myocardial perfusion imaging, increased splanchnic activity creates a problem in the visual and quantitative interpretation of the inferior and infero-septal walls of the left ventricle. We sought to determine whether the administration of diluted lemon juice or full-fat milk would be effective in reducing interfering infra-cardiac activity and therefore result in an improvement in image quality. We compared the administration of full-fat milk and diluted lemon juice to a control group that had no intervention. METHODS: The study was carried out prospectively. All patients referred to our institution for myocardial perfusion imaging from November 2009 to May 2012 were invited to be enrolled in the study. A total of 630 patients were randomised into three groups. Group 0 (G0), 246 patients, were given diluted lemon juice, group 1 (G1), 313 patients, were given full-fat milk, and group 2 (G2), 71 patients, had no intervention (control group). A routine two-day protocol was used and the patients were given the same intervention on both days. Raw data of both the stress and rest images were visually assessed for the presence of infra-cardiac activity, and quantitative grading of the relative intensity of myocardial activity to infra-cardiac activity was determined. The physicians were blinded to the intervention received and the data were reviewed simultaneously. RESULTS: The overall incidence of interfering infra-cardiac activity at stress was 84.1, 84.5 and 96.6% in G0, G1 and G2, respectively (p = 0.005). At rest it was 91.7, 90.1 and 100% in G0, G1 and G2, respectively (p = 0.0063). The visual and quantitative results favoured both milk and lemon juice in reducing the amount of interfering infra-cardiac activity versus no intervention. CONCLUSION: The administration of milk or lemon juice resulted in a significant decrease in the intensity of infra-cardiac activity compared to the control group. This reduction in intensity was even more significant in the milk group for patients assessed during rest myocardial perfusion imaging.