Usefulness of 68 Ga-Pentixafor PET/CT on Diagnosis and Management of Cushing Syndrome

Isolated Lymph Node Metastasis as Initial Presentation of Collecting Duct Carcinoma on 68Ga-Pentixafor PET/CT

ABSTRACT

A 64-year-old man was admitted to the hospital with low back pain. Enhanced CT imaging revealed an isolated retroperitoneal mass. Since primary retroperitoneal lymphoma could not be ruled out, the patient was enrolled in our clinical trial of 68Ga-pentixafor PET/CT. The mass exhibited intense uptake of 68Ga-pentixafor and was subsequently confirmed as lymph node metastasis originating from collecting duct carcinoma. Our case demonstrated that 68Ga-pentixafor may lack specificity in distinguishing primary retroperitoneal lymphomas from other conditions.

Typing diagnostic value of 68Ga-pentixafor PET/CT for patients with primary aldosteronism and unilateral nodules

PURPOSE

Our goal was to compare the lateralization of 68Ga-pentixafor PET/CT with adrenal vein sampling (AVS) in primary aldosteronism (PA) patients with unilateral lesions.

METHODS

We retrospectively enrolled 61 patients with PA and all patients showed unilateral nodular lesions on CT and underwent 68Ga-Pentixafor PET/CT. The general clinical data, imaging and AVS results were collected. The diagnostic efficiency of 68Ga-Pentixafor PET/CT imaging in PA patients was calculated by visual and semi-quantitative analysis to compare the consistency with AVS, and the correlation between CXCR4 express and 68Ga-Pentixafor uptake was performed.

RESULTS

The study included 42 unilateral PA (UPA) and 19 bilateral PA (BPA). The area under curve (AUC) of 68Ga-Pentixafor PET/CT to diagnosis UPA with 10 min maximum standardized uptake value (SUVmax) > 8.17 was 0.82 ([0.70-0.90], P < 0.001), and the sensitivity and specificity were 0.64 and 0.90, respectively. The maximal AUC of 68Ga-pentixafor PET/CT for the diagnosis UPA in patients with nodules with a diameter ≥1 cm was 0.87 ([0.73-0.95],P both <0.001,[10 min SUVmax=8.17 and 10 min mean standardized uptake value (SUVmean)=5.57]), and the sensitivity and specificity were 0.73 and 0.93, respectively. Unilateral adrenalectomy and significant CXCR4 expression were present in 32 UPA, including 27 aldosterone-producing adenoma and 5 idiopathic adrenal hyperplasia. Additionally, 68Ga-pentixafor uptake in adrenal lesions was significantly correlated with CXCR4 expression, and statistical differences in 68Ga-pentixafor uptake among IRS subgroups.

CONCLUSIONS

68Ga-Pentixafor PET/CT can be helpful for subtyping diagnosis of PA patients with unilateral adrenal nodular, showing significant potential in non-invasive PA classification.

Selective PET imaging of CXCR4 using the Al18F-labeled antagonist LY2510924

BACKGROUND

[68Ga]PentixaFor detects C-X-C chemokine receptor type 4 (CXCR4) overexpression in various malignancies, such as multiple myeloma and non-Hodgkin lymphomas, as well as in endocrine and inflammatory disorders. This study aimed to develop an Al18F-labeled radiotracer derived from LY2510924 for CXCR4-targeted imaging, leveraging the physical and logistical advantages of fluorine-18.

METHODS

We designed a CXCR4-specific radioprobe, [18F]AlF-NOTA-SC, based on LY2510924 by incorporating a triglutamate linker and NOTA chelator to enable Al18F-labeling. The in vitro CXCR4 affinity was assessed using cell-based binding assays. Subsequently, in vivo pharmacokinetics and tumor uptake of [18F]AlF-NOTA-SC were assessed in naïve mice and mice with xenografts derived from U87.CD4/U87.CD4.CXCR4 and MM.1 S cells. Finally, biodistribution was determined in a non-human primate using PET-MR.

RESULTS

Compared to Ga-PentixaFor, AlF-NOTA-SC demonstrated similar in vitro affinity for human CXCR4. [18F]AlF-NOTA-SC was produced with a decay-corrected radiochemical yield of 21.0 ± 7.1% and an apparent molar activity of 16.4 ± 3.6 GBq/µmol. In [18F]AlF-NOTA-SC binding assays on U87.CD4.CXCR4 cells, the total bound fraction was 7.1 ± 0.5% (58% blocking by AMD3100). In naïve mice, the radiotracer did not accumulate in any organs; however, it showed a significant CXCR4-specific uptake in xenografted tumors (SUVmeanU87.CD4 = 0.04 ± 0.00 (n = 3); SUVmeanU87.CD4.CXCR4 = 3.04 ± 0.65 (n = 3); SUVmeanMM.1 S = 1.95 ± 0.11 (n = 3)). In a non-human primate, [18F]AlF-NOTA-SC accumulated in CXCR4 expressing organs, such as the spleen and bone marrow.

CONCLUSION

[18F]AlF-NOTA-SC exhibited CXCR4-specific uptake in vitro and in vivo, with fast and persistent tumor accumulation, making it a strong candidate for clinical translation as an 18F-alternative to [68Ga]PentixaFor.

Mildly Increased 68 Ga-Pentixafor Uptake in Hepatic Hemangioma

ABSTRACT

68 Ga-pentixafor uptake in hemangioma is rare. We report 68 Ga-pentixafor PET/MRI findings of a hepatic hemangioma in a 54-year-old woman. The images revealed a hyperintense lesion in the right posterior liver on T2-weighted images, with mild pentixafor uptake. The lesion was consistent with typical presentations of a hemangioma on MRI and contrast-enhanced CT.

Diagnostic Accuracy and Value of CXCR4-targeted PET/MRI Using 68Ga-Pentixafor for Tumor Localization in Cushing Disease

Background Gallium 68 (68Ga) pentixafor has emerged as a potential C-X-C chemokine receptor type 4 (CXCR4)-targeted radiotracer for neuroendocrine tumor, yet its application in Cushing disease remains uncertain. Purpose To assess the diagnostic accuracy and value of 68Ga-pentixafor PET/MRI in localizing adrenocorticotropic hormone (ACTH)-secreting pituitary tumors in Cushing disease. Materials and Methods A prospective single-center study was conducted from March 2023 to February 2024 in participants with Cushing disease scheduled for surgical pituitary tumor resection. All participants underwent preoperative 68Ga-pentixafor PET/MRI and contrast-enhanced MRI. Two radiologists and nuclear medicine physicians analyzed images. Surgical and histologic findings served as the reference standard. Diagnostic performance was compared using the McNemar test. The Wilcoxon signed rank test was used to compare the maximum standardized uptake value (SUVmax) between tumor and normal pituitary. Correlations between SUVmax and histopathologic or hormone characteristics were analyzed using the Spearman coefficient and logistic regression tests. Results A total of 43 participants (median age, 37 years [IQR, 31-49 years]; 35 female) were included, with 44 pituitary lesions identified after investigational imaging scans, 41 of which were confirmed as ACTH secreting. Sensitivity and diagnostic accuracy of 68Ga-pentixafor PET/MRI were 92.7% (38 of 41 lesions; 95% CI: 80.6, 97.5) and 88.6% (39 of 44 lesions; 95% CI: 76.0, 95.0), respectively, which were higher compared with that of contrast-enhanced MRI (78.0% [32 of 41 lesions; 95% CI: 63.3, 88.0] and 77.3% [34 of 44 lesions; 95% CI: 63.0, 87.2], respectively). Both techniques combined improved sensitivity to 100% (41 of 41 lesions; 95% CI: 91.4, 100.0) and accuracy to 95.5% (42 of 44 lesions; 95% CI: 84.9, 99.2) (P = .01). ACTH-secreting pituitary tumors exhibited a higher SUVmax than normal pituitary (3.9 vs 1.3, P < .001). The SUVmax exhibited a positive correlation with CXCR4 H-score (R = 0.5 [95% CI: 0.2, 0.7], P < .001) and ACTH levels (R = 0.4 [95% CI: 0.1, 0.6], P = .01). Conclusion 68Ga-pentixafor PET/MRI demonstrated high sensitivity in localizing ACTH-secreting pituitary tumors. 68Ga-pentixafor uptake was associated with CXCR4 expression and ACTH level. © RSNA, 2024 Supplemental material is available for this article.

Diagnostic and therapeutic approaches to a case of pregnancy complicated by bilateral adrenocortical adenomas with primary aldosteronism and Cushing's syndrome

Aldosterone/cortisol co-secreting adenomas (A/CPA) are a rare type of primary aldosteronism(PA), and cases of aldosterone/cortisol co-secreting adenomas during pregnancy are extremely rare, with no reported cases to date. The unique physiological state of pregnancy increases cortisol secretion through the hypothalamic-pituitary-adrenal (HPA) axis and leads to elevated levels of all components of the renin-angiotensin-aldosterone system (RAAS). This can cause overlapping symptoms with abnormal cortisol and aldosterone secretion, making diagnosis very challenging. This case involves a 29-year-old woman who developed hypercortisolism at 33 weeks of pregnancy. Despite receiving treatment for her symptoms and having a successful delivery, she continued to experience hypertension and hypokalaemia after giving birth. Eventually, she was diagnosed with ACTH-independent Cushing's syndrome and primary aldosteronism due to independent cortisol and aldosterone secretion from bilateral adrenal adenomas. Following a thorough diagnosis, classification, treatment, and follow-up, the patient achieved a clinical cure while preserving normal adrenal function. Further investigation revealed that both diseases were caused by KCNJ5 and PRKACA mutations found in the bilateral adrenal adenomas.

CXCR4-Targeted 68 Ga-Pentixafor PET/CT Imaging in Inflammatory Bowel Disease

PURPOSE

To investigate the role of CXCR4-targeted 68 Ga-pentixafor PET/CT imaging in inflammatory bowel disease (IBD).

METHODS

Five IBD patients and 12 control subjects performing 68 Ga-pentixafor PET/CT examinations were included. 68 Ga-pentixafor PET/CT imaging and endoscopic findings were recorded and compared. The semiquantitative parameters of 68 Ga-pentixafor uptake by the lesion segments in IBD patients and the normal intestines in the control were investigated.

RESULTS

Among these 5 IBD patients, endoscopy successfully examined a total of 26 intestinal segments, with 13 segments showing endoscopic lesions. 68 Ga-pentixafor PET/CT was positive in all endoscopy-proven lesions (13/13). Additionally, 68 Ga-pentixafor PET/CT revealed the lesions in small intestines and colons that cannot be reached by endoscopy due to severe stenosis, and mesenteric lymphadenitis accompanied IBD. The SUV max of the lesion segments in IBD patients was significantly higher than that of the normal intestines in the control group (median, 3.15 [range, 1.61-6.26] vs 1.67 [1.18-2.29], P < 0.001). Moreover, the SUV max ratios of the lesion segments/liver or blood pool were higher when compared with the control (2.20 [1.13-3.26] vs 0.85 [0.54-1.20]; 1.66 [0.94-2.95] vs 0.67 [0.52-1.04]; P ≤ 0.001).

CONCLUSIONS

68 Ga-pentixafor PET/CT can be a potentially valuable tool to assess the active intestinal lesions of IBD with high sensitivity. Moreover, this noninvasive approach does not require fasting or bowel preparation, offering good tolerance and safety.

68Ga-pentixafor PET/CT in the localization diagnosis of primary aldosteronism concurrent subclinical cushing's syndrsome: two case reports

PURPOSE

Adrenal venous sampling (AVS) is recommended for subtyping primary aldosteronism (PA). However, in cases of PA, concurrent subclinical Cushing's syndrome (SCS) has the potential to confound AVS results. Pentixafor, a CXC chemokine receptor type 4-specific ligand, has been reported as a promising marker to evaluate functional nature of adrenal adenomas. This study aims to investigate the clinical value of Gallium-68 Pentixafor Positron Emission Tomography-Computed Tomography (68Ga-Pentixafor PET/CT) in the localization diagnosis of patients with PA plus SCS.

METHODS

Two patients with a confirmed diagnosis of PA plus SCS underwent AVS and 68Ga-Pentixafor PET/CT.

RESULTS

AVS results revealed no lateralization for both patients while 68Ga-Pentixafor PET/CT showed a unilateral adrenal nodule with increased uptake of 68Ga-Pentixafor. Unilateral adrenalectomy was performed based on the results of 68Ga-Pentixafor PET/CT. Subsequently, complete biochemical remission of autonomous aldosterone and cortisol secretion were achieved in both cases.

CONCLUSIONS

68Ga-Pentixafor PET/CT shows promising potential for the localization of aldosterone and cortisol co-secreting adrenal adenoma in patients with PA plus SCS.

Ectopic adrenocortical adenoma characterized by hypogonadism: a case report and review of the literature

BACKGROUND

Currently, there is a scarcity of cases and diagnostic data regarding ectopic adrenocortical adenomas, particularly in relation to their impact on gonadal function and localization diagnostic techniques. We report a typical case of ectopic adrenocortical adenomas and the data of treatment follow-up, and review the literature of 31 available cases of ectopic adrenocortical adenomas.

CASE PRESENTATION

A 27-year-old Chinese female patient was admitted to our hospital for hypertension, hyperglycaemia and primary amenorrhea. The patient was functionally diagnosed with ACTH-independent CS and hypogonadotropic hypogonadism. Radiological evaluations, including Computed Tomography (CT) and functional imaging, identified a mass at the left renal hilum. Histological assessments post-surgical excision confirmed the mass to be an ectopic adrenocortical adenoma. A subsequent 3-month follow-up showed no signs of disease recurrence, a swift recovery of the cortisol axis was observed, with a partial recuperation of the gonadal axis.

REVIEW

Our literature review shows that the most common ectopic areas of cortisol adenomas are renal hilum and hepatic region. The most positive biomarker is Melan A, and only a few cases have been diagnosed with functional localization.

CONCLUSION

Ectopic adrenocortical adenomas may be asymptomatic in the early stage and can impact gonadal function. Physicians who treat hypogonadism must be aware of the need to test cortisol levels and perform functional localization in patients with lumps present.

Synthesis, Screening, and Evaluation of Theranostic Molecular CPCR4-Based Probe Targeting CXCR4

Chemokines and chemokine receptors are indispensable to play a key role in the development of malignant tumors. As one of the most widely expressed chemokine receptors, chemokine (C-X-C motif) receptor 4 (CXCR4) has been a popular research focus. In most tumors, CXCR4 expression is significantly upregulated. Moreover, integrated nuclide diagnosis and therapy targeting CXCR4 show great potential. [68Ga]Ga-pentixafor, a radioligand targeting CXCR4, exhibits a strong affinity for CXCR4 both in vivo and in vitro. However, [177Lu]Lu-pentixather, the therapeutic companion of [68Ga]Ga-pentixafor, requires significant refinement to mitigate its pronounced hepatic biodistribution. The objective of this study was to synthesize theranostic molecular tracers with superior CXCR4 targeting functions. The Daudi cell line, which highly expressed CXCR4, and the MM.1S cell line, which weakly expressed CXCR4, were used in this study. Based on the pharmacophore cyclo (-d-Tyr-n-me-d-Orn-l-Arg-L-2-NAL-Gly-) (CPCR4) of pentixafor, six tracers were synthesized: [124I]I-1 ([124I]I-CPCR4), [99mTc]Tc-2 ([99mTc]Tc-HYNIC-CPCR4), [124I]I-3 ([124I]I-pentixafor), [18F]AlF-4 ([18F]AlF-NETA-CPCR4), [99mTc]Tc-5 ([99mTc]Tc-MAG3-CPCR4) and [124I]I-6 ([124I]I-pentixafor-Ga) and their radiochemical purities were all higher than 95%. After positron emission tomography (PET)/single-photon emission computed tomography (SPECT) imaging, the [124I]I-6 group exhibited the best target-nontarget ratio. At the same time, comparing the [68Ga]Ga-pentixafor group with the [124I]I-6 group, we found that the [124I]I-6 group had a better target-nontarget ratio and lower uptake in nontarget organs. Therefore, compound 6 was selected for therapeutic radionuclide (131I) labeling, and the tumor-bearing animal models were treated with [131I]I-6. The volume of the tumor site was significantly reduced in the treatment group compared with the control group, and no significant side effects were found. [124I]I-6 and [131I]I-6 showed excellent affinity for targeting CXCR4, and they showed great potential for the integrated diagnosis and treatment of tumors with high CXCR4 expression.

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.

Advances in PET Imaging of the CXCR4 Receptor: [68Ga]Ga-PentixaFor

[68Ga]Ga-PentixaFor, a PET agent targeting CXCR4 is emerging as a versatile radiotracer with promising applications in oncology, cardiology and inflammatory disease. Preclinical work in various cancer cell lines have demonstrated high specificity and selectivity. In human investigations of several tumors, the most promising applications may be in multiple myeloma, certain lymphomas and myeloproliferative neoplasms. In the nononcologic setting, [68Ga]Ga-PentixaFor could greatly improve detection for primary aldosteronism and other endocrine abnormalities. Similarly, atherosclerotic disease and other inflammatory conditions could also benefit from enhanced identification by CXCR4 targeting. Rapidly cleared from the body with a favorable imaging and radiation dosimetry profile that has been already studied in over 1000 patients, [68Ga]Ga-PentixaFor is a worthy agent for further clinical exploration with potential for theranostic applications in hematologic malignancies.

Molecular Imaging of Pituitary Tumors

Tumors of the pituitary gland, although mostly benign adenomas, are a cause of significant morbidity and even excess mortality due to local compressive effects (eg visual loss, hypopituitarism) and unregulated hormone secretion (eg acromegaly or Cushing Disease). Surgery, radiotherapy, and medical management (sometimes in combination) may be needed to mitigate the effects of tumor expansion and endocrine dysfunction. Magnetic resonance imaging (MRI) plays a central role in treatment planning for most patients. However, it does not always reliably identify the site(s) of primary or recurrent disease, especially where post-treatment remodeling results in indeterminate anatomical appearances. In these contexts, molecular imaging is a potential game-changer, allowing precise localization of sites of active disease and enabling safe and effective targeted intervention when patients would otherwise be consigned to expensive life-long medication. For pituitary and parasellar imaging, PET is the preferred modality due to its superior spatial resolution and sensitivity compared with SPECT, and an array of PET radioligands have been studied in different pituitary adenoma (PA) subtypes. While 18F-fluorodeoxyglucose (18F-FDG) is widely available, significant heterogeneity in tumoral uptake has limited its use. Instead, ligands targeting specific molecular pathways relevant to PA biology (eg somatostatin or dopamine receptor expression, amino acid uptake) are increasingly preferred and are beginning to find application in routine clinical practice. In addition, novel approaches to distinguish adenomatous tissue from normal gland (eg through comparison of images obtained with different radiotracers) and increase confidence that a suspected abnormal focus is indeed pathological (eg through subtraction imaging) have been proposed. It is likely therefore that molecular imaging will continue to find increasing application in the management of pituitary tumors just as it already does in other endocrine disorders.

Continuing Challenges in the Definitive Diagnosis of Cushing's Disease: A Structured Review Focusing on Molecular Imaging and a Proposal for Diagnostic Work-Up

The definitive diagnosis of Cushing's disease (CD) in the presence of pituitary microadenoma remains a continuous challenge. Novel available pituitary imaging techniques are emerging. This study aimed to provide a structured analysis of the diagnostic accuracy as well as the clinical use of molecular imaging in patients with ACTH-dependent Cushing's syndrome (CS). We also discuss the role of multidisciplinary counseling in decision making. Additionally, we propose a complementary diagnostic algorithm for both de novo and recurrent or persistent CD. A structured literature search was conducted and two illustrative CD cases discussed at our Pituitary Center are presented. A total of 14 CD (n = 201) and 30 ectopic CS (n = 301) articles were included. MRI was negative or inconclusive in a quarter of CD patients. ¹¹C-Met showed higher pituitary adenoma detection than ¹⁸F-FDG PET-CT (87% versus 49%). Up to 100% detection rates were found for ¹⁸F-FET, ⁶⁸Ga-DOTA-TATE, and ⁶⁸Ga-DOTA-CRH, but were based on single studies. The use of molecular imaging modalities in the detection of pituitary microadenoma in ACTH-dependent CS is of added and complementary value, serving as one of the available tools in the diagnostic work-up. In selected CD cases, it seems justified to even refrain from IPSS.

ACTH-Secreting Renal Neuroendocrine Tumor on 68 Ga-DOTATATE PET/CT

ABSTRACT

Adrenocorticotropic hormone (ACTH)-secreting renal neuroendocrine tumor (NET) is extremely rare. A left renal mass was detected on ultrasound in a 26-year-old patient with ACTH-dependent Cushing syndrome. The lesion demonstrated slightly high density and moderate uptake of radiotracer on 68 Ga-DOTATATE PET/CT, suspected to be a NET. Renal vein sampling revealed excessive ACTH secretion from the left kidney. Histopathological examination after surgery finally confirmed the diagnosis of a functioning renal NET.

Accuracy of Gallium-68 Pentixafor Positron Emission Tomography-Computed Tomography for Subtyping Diagnosis of Primary Aldosteronism

IMPORTANCE

Adrenal vein sampling (AVS) is the recommended procedure for subtyping primary aldosteronism (PA) as unilateral PA (UPA) or bilateral PA (BPA), with different treatment needed for each: adrenalectomy for UPA and medication for BPA. However, AVS is invasive and technically difficult, and how to subtype PA noninvasively is currently a great challenge.

OBJECTIVE

To evaluate the accuracy of gallium-68 pentixafor positron emission tomography-computed tomography (PET-CT) in subtyping PA using AVS as a reference standard.

DESIGN, SETTING, AND PARTICIPANTS

This diagnostic study was conducted at a tertiary hospital in China among patients diagnosed with PA. Enrollment was started in November 2021, with follow-up ending in May 2022.

EXPOSURES

: Patients were recruited to undergo gallium-68 pentixafor PET-CT and AVS.

MAIN OUTCOMES AND MEASURES

Maximum standardized uptake value (SUVmax) of each adrenal gland during PET-CT was measured to calculate the lateralization index of SUVmax. Area under the receiver operating characteristic curve (AUROC), specificity, and sensitivity were used to analyze the accuracy of the lateralization index based on SUVmax for subtyping PA.

RESULTS

Among 100 patients with PA who completed the study (47 female [47.0%] and 53 male [53.0%]; median [IQR] age, 49 [38-56] years), 43 individuals had UPA and 57 individuals had BPA. Aldosterone-cortisol ratio (Spearman ρ = 0.26; P < .001) in adrenal veins was positively correlated with SUVmax of adrenal glands at 10 minutes during PET-CT. Using lateralization index based on SUVmax at 10 minutes to identify UPA, the AUROC was 0.90 (95% CI, 0.83-0.97). A cutoff value for lateralization index based on SUVmax at 10 minutes set at 1.65 conferred a specificity of 1.00 (95% CI, 0.94-1.00) and sensitivity of 0.77 (95% CI, 0.61-0.88). The diagnostic concordance rate of PET-CT and AVS was 90 patients (90.0%) compared with 54 patients (54.0%) between traditional CT and AVS.

CONCLUSIONS AND RELEVANCE

This study found good diagnostic accuracy of gallium-68 pentixafor PET-CT in differentiating UPA from BPA. These findings suggest that gallium-68 pentixafor PET-CT may be used to avoid invasive AVS in some patients with PA.

Adrenal functional imaging - which marker for which indication?

PURPOSE OF REVIEW

In recent years, a broad spectrum of molecular image biomarkers for assessment of adrenal functional imaging have penetrated the clinical arena. Those include positron emission tomography and single photon emission computed tomography radiotracers, which either target glucose transporter, CYP11B enzymes, C-X-C motif chemokine receptor 4, norepinephrine transporter or somatostatin receptors. We will provide an overview of key radiopharmaceuticals and determine their most relevant clinical applications, thereby providing a roadmap for the right image biomarker at the right time for the right patient.

RECENT FINDINGS

Numerous radiotracers for assessment of adrenal incidentalomas ([18F]FDG; [123I]IMTO/IMAZA), ACC ([123I]IMTO/IMAZA; [18F]FDG; [68Ga]PentixaFor), pheochromocytomas and paragangliomas ([123I]mIBG; [18F]flubrobenguane; [18F]AF78; [68Ga]DOTATOC/-TATE), or primary aldosteronism ([11C]MTO, [68Ga]PentixaFor) are currently available and have been extensively investigated in recent years. In addition, the field is currently evolving from adrenal functional imaging to a patient-centered adrenal theranostics approach, as some of those radiotracers can also be labeled with ß-emitters for therapeutic purposes.

SUMMARY

The herein reviewed functional image biomarkers may not only allow to increase diagnostic accuracy for adrenal gland diseases but may also enable for achieving substantial antitumor effects in patients with adrenocortical carcinoma, pheochromocytoma or paraganglioma.