First-in-human evaluation of [18F]CETO: a novel tracer for adrenocortical tumours

Radiation dosimetry of para-chloro-2-[18F]fluoroethyl-etomidate: a PET tracer for adrenocortical imaging

BACKGROUND

[11C]metomidate, a methyl ester analogue of etomidate, is used for positron emission tomography of adrenocortical cancer, and has been tested in recent clinical trials for lateralization in primary aldosteronism (PA). However, in PA, visualization as well as uptake quantification are hampered by the tracer's rather high non-specific liver uptake, and its overall clinical usefulness is also limited by the short 20-minute half-life of carbon-11. Therefore, we evaluated para-chloro-2-[18F]fluoroethyl-etomidate, [18F]CETO, a fluorine-18 (T1/2=109.8 min) analogue, as a potential new adrenocortical PET tracer. The aim of this study was to assess radiation dosimetry of [18F]CETO.

RESULTS

[18F]CETO showed a high uptake in adrenal glands, still increasing at 5 h post injection. Adrenal glands (absorbed dose coefficients 0.100 ± 0.032 mGy/MBq in males and 0.124 ± 0.013 mGy/MBq in females) received the highest absorbed dose. The effective dose coefficient was 20 µSv/MBq.

CONCLUSIONS

[18F]CETO has a favourable biodistribution in humans for adrenal imaging. The effective dose for a typical clinical PET examination with 200 MBq [18F]CETO is 4 mSv.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT05361083 Retrospectively registered 29 April 2022. at, URL: https://clinicaltrials.gov/ct2/show/NCT05361083.

Treating Primary Aldosteronism-Induced Hypertension: Novel Approaches and Future Outlooks

Primary aldosteronism (PA) is the most common cause of secondary hypertension and is associated with increased morbidity and mortality when compared with blood pressure-matched cases of primary hypertension. Current limitations in patient care stem from delayed recognition of the condition, limited access to key diagnostic procedures, and lack of a definitive therapy option for nonsurgical candidates. However, several recent advances have the potential to address these barriers to optimal care. From a diagnostic perspective, machine-learning algorithms have shown promise in the prediction of PA subtypes, while the development of noninvasive alternatives to adrenal vein sampling (including molecular positron emission tomography imaging) has made accurate localization of functioning adrenal nodules possible. In parallel, more selective approaches to targeting the causative aldosterone-producing adrenal adenoma/nodule (APA/APN) have emerged with the advent of partial adrenalectomy or precision ablation. Additionally, the development of novel pharmacological agents may help to mitigate off-target effects of aldosterone and improve clinical efficacy and outcomes. Here, we consider how each of these innovations might change our approach to the patient with PA, to allow more tailored investigation and treatment plans, with corresponding improvement in clinical outcomes and resource utilization, for this highly prevalent disorder.

A cost-analysis of managing secondary and apparent treatment-resistant hypertension in a specialist multidisciplinary hypertension clinic

OBJECTIVES

A knowledge gap exists around the costs and budget impact of specialist hypertension clinics. This study reports on the cost of providing care in a multidisciplinary hypertension clinic staffed by nephrologist, endocrinologist and cardiologist, which manages patients with suspected secondary hypertension and/or apparent treatment-resistant hypertension. The aim of this study is to provide the evidence required to inform policy and planning care pathways for this patient group.

METHODS

A cost analysis from a healthcare provider perspective using micro-costing techniques was conducted to estimate the direct implementation costs of existing standard practice for the care pathway of patients attending the multidisciplinary hypertension clinic. Sixty-five patients originally recruited for a study of medication adherence in hypertension were included in the sample.

RESULTS

The total care-pathway cost per patient, taking into account clinic visits, clinical reviews, investigations and MDT discussion, was estimated to be €3277, on average. For the patient subgroups, the average cost was €5644 for patients diagnosed with primary aldosteronism and €1446 for patients diagnosed with essential hypertension.

CONCLUSION

There is significant cost associated with providing specialized hypertension care for patients with apparent treatment-resistant hypertension. Given the high rates of nonadherence in this population, it is likely that some of this cost could be avoided with better detection and management of medication adherence in this challenging population. Future studies should consider the cost-effectiveness of this or similar models of care by exploring the benefit to patients and the wider healthcare context of providing care of this type.

Primary aldosteronism: molecular medicine meets public health

Primary aldosteronism is the most common single cause of hypertension and is potentially curable when only one adrenal gland is the culprit. The importance of primary aldosteronism to public health derives from its high prevalence but huge under-diagnosis (estimated to be <1% of all affected individuals), despite the consequences of poor blood pressure control by conventional therapy and enhanced cardiovascular risk. This state of affairs is attributable to the fact that the tools used for diagnosis or treatment are still those that originated in the 1970-1990s. Conversely, molecular discoveries have transformed our understanding of adrenal physiology and pathology. Many molecules and processes associated with constant adrenocortical renewal and interzonal metamorphosis also feature in aldosterone-producing adenomas and aldosterone-producing micronodules. The adrenal gland has one of the most significant rates of non-silent somatic mutations, with frequent selection of those driving autonomous aldosterone production, and distinct clinical presentations and outcomes for most genotypes. The disappearance of aldosterone synthesis and cells from most of the adult human zona glomerulosa is the likely driver of the mutational success that causes aldosterone-producing adenomas, but insights into the pathways that lead to constitutive aldosterone production and cell survival may open up opportunities for novel therapies.

Key to the Treatment of Primary Aldosteronism in Secondary Hypertension: Subtype Diagnosis

PURPOSE OF REVIEW

Primary aldosteronism (PA) is a leading global cause of secondary hypertension. Subtyping diagnosis of PA is the key to surgery, but accurate classification of PA is crucial but challenging in clinical diagnosis and treatment. The purpose of this review is to provide a summary of current literature and propose subtyping diagnosis flow chart to help us classify PA quickly and accurately.

RECENT FINDINGS

Early diagnosis and accurate typing are essential for the timely treatment and appropriate management of PA. For most patients, adrenal venous sampling (AVS) is the central choice for typing diagnosis, but AVS is invasive and difficult to promote effectively. CT can help identify unilateral typical adenomas in select patients to avoid AVS. New radionuclide imaging has shown value in the diagnosis and classification of PA, which distinguishes adrenocortical hyperplasia from adenoma and can replace AVS in some patients. Accurately diagnosing unilateral PA is crucial for determining the appropriate treatment strategy for PA. The simple flow chart of PA subtyping diagnosis based on the current literature needs to be verified and evaluated by follow-up researches.

Advances in the molecular imaging of primary aldosteronism

Primary aldosteronism (PA) is the most common cause of secondary hypertension. It predisposes to adverse outcomes such as nephrotoxicity and cardiovascular damage, which are mediated by direct harm from hypertension to the target organs. Accurate subtype diagnosis and localization are crucial elements in choosing the type of treatment for PA in clinical practice since the dominant side of aldosterone secretion in PA affects subsequent treatment options. The gold standard for diagnosing PA subtypes, adrenal venous sampling (AVS), requires specialized expertise, the invasive nature of the procedure and high costs, all of which delay the effective treatment of PA. Nuclide molecular imaging is non-invasive and has wider applications in the diagnosis and treatment of PA. This review aims to provide a summary of the application of radionuclide imaging in the diagnosis, treatment management and prognostic assessment of PA.

A Molecular Toolbox of Positron Emission Tomography Tracers for General Anesthesia Mechanism Research

With appropriate radiotracers, positron emission tomography (PET) allows direct or indirect monitoring of the spatial and temporal distribution of anesthetics, neurotransmitters, and biomarkers, making it an indispensable tool for studying the general anesthesia mechanism. In this Perspective, PET tracers that have been recruited in general anesthesia research are introduced in the following order: 1) ¹¹C/¹⁸F-labeled anesthetics, i.e., PET tracers made from inhaled and intravenous anesthetics; 2) PET tracers targeting anesthesia-related receptors, e.g., neurotransmitters and voltage-gated ion channels; and 3) PET tracers for studying anesthesia-related neurophysiological effects and neurotoxicity. The radiosynthesis, pharmacodynamics, and pharmacokinetics of the above PET tracers are mainly discussed to provide a practical molecular toolbox for radiochemists, anesthesiologists, and those who are interested in general anesthesia.