Acute spontaneous non-hemorrhagic adrenal infarction with systemic lupus erythematosus and antiphospholipid antibody syndrome: A case report.

RATIONALE: Adrenal infarction (AI) is a rare type of adrenal damage, which is relatively common in systemic lupus erythematosus, antiphospholipid antibody syndrome (APS) and pregnancy. The diagnosis of AI is mainly by computed tomography (CT) and magnetic resonance imaging, but is easily confused with other adrenal disease. Hence, this report details a condition of AI with systemic lupus erythematosus, APS and made a differential diagnosis from imaging. PATIENT CONCERNS: We report a case of a 55-year-old woman with pain in her fossa axillaries and inguinal regions. Then CT scan disclosed bilateral adrenal diseases, and the patient was diagnosed with systemic lupus erythematosus, APS and AI after additional autoimmune examinations. DIAGNOSES: The patient was diagnosed as systemic lupus erythematosus with lupus nephritis, hematological damage and oromeningitis, APS, AI and secondary blood coagulation disorders. INTERVENTIONS: The patient was treated with methylprednisolone, hydroxychloroquine and low molecular heparin. OUTCOMES: The patient relieves and remains well 1 year after treatment. LESSONS SUBSECTIONS: AI can be divided hemorrhagic and non-hemorrhagic, with bilateral lesions more common. In our case, the AI was bilateral, partially involved and non-hemorrhagic, and the "cutoff sign" was first put forward in CT, which might assist the diagnosis.

[Evaluation of the anatomical morphology of the adrenal veins in patients with primary aldosteronism by adrenal venous sampling].

Objective: To analyze the anatomical characteristics of the adrenal veins through adrenal venography to improve the success rate of adrenal venography (AVS). Methods: This study was a cross-sectional study. Patients who were diagnosed with primary aldosteronism and underwent AVS from January 2019 to October 2023 at the First Affiliated Hospital of Dalian Medical University were included. Adrenal vein imaging was collected from the enrolled patients. We performed statistical analysis on the adrenal vein orifice position, inflow angle, and adrenal venography morphology. The adrenal venous orifice was defined as the location where the catheter was placed at the end of the calm inhalation. Spearman correlation analysis was used to explore the relationship between the positions of bilateral adrenal vein orifices and body mass index (BMI). Results: A total of 282 patients with successful bilateral AVS and complete bilateral adrenal vein imaging were enrolled, of whom 57.1% (161/282) were male and the age was (53.3±10.7) years old. The orifice of the left adrenal vein was located between the middle segment of the 11th thoracic vertebra and the upper segment of the 2nd lumbar vertebra. The inflow angle relative to the position of the orifice was all leftward and upward. The orifice of the right adrenal vein was located between the upper segment of the 11th thoracic vertebra and the lower segment of the 1st lumbar vertebra, and 91.1% (257/282) had a rightward and downward angle of inflow relative to the position of the orifice. The position of the adrenal vein orifices on both the left (r=0.211, P<0.001) and right (r=0.196, P=0.001) showed positive correlation with BMI. The position of the right adrenal vein orifice also increased with the position of the left adrenal orifice (r=0.530, P<0.001). The most common adrenal venography morphology on the right side was triangular (36.5%, 103/282), while the most common venography morphology on the left side was glandular (66.3%, 187/282). Conclusions: The anatomical morphology of adrenal veins are diverse. Being familiar with the morphological characteristics of the adrenal vein and identifying the adrenal vein accurately during surgery has important clinical value in improving the success rate of AVS.

Adrenal gland injury in trauma patients and its impact on clinical outcomes.

BACKGROUND: Adrenal gland injury (AGI) associated with trauma is an uncommon and often overlooked condition. This study aimed to evaluate the frequency of AGI in individuals with severe trauma injuries and investigate the outcomes of patients with AGI. METHODS: All patients admitted to a tertiary trauma referral center under the trauma protocol who had a computed tomography (CT) scan between January 2012 and January 2023 were analyzed retrospectively. Patients who were dead on arrival and patients with incomplete data were excluded. They were classified into two main groups, adult and pediatric, and further subcategorized by the presence or absence of radiologically evident AGI. Demographic data, mechanism of injury, injury severity scores (ISS), presence of concurrent abdominal injury, and 30-day mortality rates were compared. A separate analysis was performed for factors affecting mortality rates. RESULTS: A total of 1,253 patients were included: 950 adults and 303 pediatric patients. In the adult group, AGI was detected in 45 (4.7%) patients and was more commonly associated with the following mechanisms of injury: motor vehicle accidents (26.7% vs. 14.3%) and pedestrian accidents (37.8% vs. 15.5%). Injury to the right side was more common (55.6%). Patients with AGI had higher rates of concurrent liver (17.8% vs. 3.9%), spleen (11.1% vs. 3.6%), and kidney injuries (15.6% vs. 1.3%). In the pediatric population, AGI was detected in 30 patients (14.8%), a significantly higher rate compared to the adult group. Similar to the adult group, AGI was more commonly associated with concurrent abdominal injuries and had a right-sided dominance (60%), but the rate of concurrent abdominal injuries was higher in the pediatric group (80% vs. 46%). The 30-day mortality was significantly higher in both adult and pediatric AGI groups compared to patients without AGI (adult: 15.6% vs. 2.9%, pediatric: 10% vs. 1.8%). In patients with AGI, major head and neck injuries and chest injuries were associated with mortality. CONCLUSION: Adrenal gland injuries due to trauma are not uncommon. They are usually associated with blunt trauma and other concurrent abdominal organ injuries. The major contributors to mortality in patients with AGI were major head and neck injuries and chest injuries.

Super Mario sign at somatostatin receptor PET/CT.

68Ga-DOTA NOC PET-CT imaging has been shown to have high accuracy for the evaluation of neuroendocrine tumours. We present the case of a 59-year-old male with well differentiated gastric neuroendocrine tumour (grade II) treated with surgery. 68Ga-DOTA NOC PET/CT was performed to rule out metastasis. 68Ga-DOTA NOC showed physiological uptake in the bilateral adrenal and horseshoe kidney appearing as the famous character Super Mario. There is no evidence of any abnormal somatostatin avid lesion.

MRI-based adrenal gland volume is associated with cardiovascular alterations in individuals without prior cardiovascular disease.

Aim of this study was to analyse the associations of cardiovascular health and adrenal gland volume as a rather new imaging biomarker of chronic hypothalamic-pituitary-adrenal (HPA) axis activation. The study population originates from the KORA population-based cross-sectional prospective cohort. 400 participants without known cardiovascular disease underwent a whole-body MRI. Manual segmentation of adrenal glands was performed on VIBE-Dixon gradient-echo sequence. MRI based evaluation of cardiac parameters was achieved semi-automatically. Cardiometabolic risk factors were obtained through standardized interviews and medical examination. Univariate and multivariate associations were derived. Bi-directional causal mediation analysis was performed. 351 participants were eligible for analysis (56 ± 9.1 years, male 58.7%). In multivariate analysis, significant associations were observed between adrenal gland volume and hypertension (outcome hypertension: Odds Ratio = 1.11, 95% CI [1.01, 1.21], p = 0.028), left ventricular remodelling index (LVRI) (outcome LVRI: ß = 0.01, 95% CI [0.00, 0.02], p = 0.011), and left ventricular (LV) wall thickness (outcome LV wall thickness: ß = 0.06, 95% CI [0.02, 0.09], p = 0.005). In bi-directional causal mediation analysis adrenal gland volume had a borderline significant mediating effect on the association between hypertension and LVRI (p = 0.052) as well as wall thickness (p = 0.054). MRI-based assessment of adrenal gland enlargement is associated with hypertension and LV remodelling. Adrenal gland volume may serve as an indirect cardiovascular imaging biomarker.

Evaluation of adrenal vein anatomy by adrenal venous sampling in patients with primary aldosteronism in Chinese.

Accurate cannulation of the adrenal vein is challenging during adrenal venous sampling (AVS) because of the variations in adrenal vein anatomy. This study aimed to investigate the adrenal venous morphology in Chinese and improve the success rate of AVS. A total of 221 participants with primary aldosteronism (PA) who underwent AVS were enrolled. Compare the morphology among subgroups divided according to sex, body mass index (BMI), and with or without adenoma. The success rate of right, left, and bilateral AVS was 98.60%, 97.20%, and 96.85%, respectively. The triangular pattern was the most common (39.37%) on the right side, while the glandlike pattern (70.14%) on the left. The proportion of adrenal venous morphology varies among patients with different sexes (χ2 = 21.335, P < .001), BMI (χ2 = 10.642 P = .031), and with or without adenoma (χ2 = 10.637, P = .031) on the right side, and the male, obese and adenoma group showed a higher proportion of glandlike pattern than triangular pattern. If only dependent on computed tomography, 9.05% of patients incorrectly diagnose the dominant side, 14.48% of patients would have inappropriate surgery meanwhile 25.34% of patients would miss the surgical opportunity. In conclusion, the most common types of right and left adrenal venous morphology were triangular pattern and glandlike pattern, respectively. Sex, BMI, and the presence of adenoma affected right adrenal venous morphology. Adequate knowledge of the adrenal venous morphology is critical for improving the success rate of AVS and making an appropriate treatment for PA.

Primary diffuse large B-cell lymphoma of adrenal gland: A case report.

INTRODUCTION: Most adrenal tumors are benign and primary adrenal malignancies are relatively rare. Primary adrenal lymphoma (PAL) is a very rare and highly aggressive malignant tumor with unknown etiology, atypical clinical symptoms, nonspecific imaging manifestations, difficult disease diagnosis and poor prognosis. CASE REPORT: This case report details a 42-year-old woman who was admitted to the hospital with a 1-year-old bilateral adrenal mass and 1-month-old left upper abdominal pain. Enhanced CT of the abdomen showed a right adrenal nodule and a large occupying lesion in the left adrenal region, with a high probability of pheochromocytoma. Intraoperatively, a huge tumor measuring about 12*12*10 cm was found in the left adrenal region, infiltrating the left kidney, spleen and pancreatic tail. Postoperative pathology: lymphocytes were found in the renal capsule and subcapsule, lymphocytes were found in the pancreas; lymphocytes were found in the spleen. Consider a tumor of the lymphohematopoietic system, possibly lymphoma. CONCLUSION: This case demonstrates that primary adrenal diffuse large B-cell lymphoma (PADLBCL) is highly aggressive, has a poor prognosis, is prone to recurrence, has poor therapeutic outcomes, and is difficult to diagnose. Clinicians should consider the possibility of PADLBCL when encountering huge adrenal-occupying lesions and consider chemotherapy before surgery. Reducing the tumor size before surgery is a more favorable therapeutic approach, thus prolonging the patient life and improving the quality of survival.

Beyond symptomatology: A comparative analysis of unilateral and bilateral macronodular mild autonomous cortisol secretion.

OBJECTIVE: To investigate the clinical, laboratory findings and signal intensity index (SII) on magnetic resonance imaging (MRI) of patients with bilateral and unilateral macronodular mild autonomous cortisol secretion (MACS). PATIENTS AND MEASUREMENTS: Clinical and laboratory findings of 81 patients with MACS were examined from retrospective records. SII of adenomas and internodular areas were evaluated by MRI. The unilateral group included patients with an adrenal macronodule (≥1 cm) in a single adrenal gland, while the bilateral group included patients with at least one macronodule in both adrenal glands. RESULTS: In total, 46 patients were in the unilateral (57%), while 35 (43%) patients were in the bilateral groups. The dehydroepiandrosterone sulphate (DHEA-S) level was lower in the unilateral than in the bilateral group (p < .001). The presence of type 2 diabetes mellitus (T2DM), glycosylated haemoglobin (HbA1c) and low-density lipoprotein (LDL) concentrations were higher in the bilateral group (p < .05). However, no significant difference was detected in terms of adrenocorticotropic hormone (ACTH) and overnight 1 mg dexamethasone suppression test (DST) between the two groups (p > .05). There was no difference in SII between adenomas within the same patient, as well as between the unilateral and bilateral groups (p > .05). Logistic regression analysis based on the differentiation between unilateral and bilateral macronodular MACS demonstrated that DHEA-S, HbA1c and LDL concentrations were associated factors. CONCLUSION: DHEA-S levels may not be as suppressed in patients with bilateral macronodular MACS as compared to those with unilateral adenoma. T2DM and hypercholesterolaemia have a higher frequency in bilateral patients. However, ACTH, overnight 1 mg DST and SII may not provide additional information for differentiation of bilaterality and unilaterality.

Pre-procedural and intra-procedural computerized tomography: providing a roadmap for successful adrenal venous sampling procedures.

BACKGROUND AND PURPOSE: Adrenal venous sampling (AVS) is used for the diagnosis of primary hyperaldosteronism. Technical difficulties with right adrenal vein (RAV) catheterization can lead to erroneous results. Our purpose was to delineate the location of the RAV on pre-procedural CT imaging in relation to the location identified during AVS and to report on the impact of successful RAV cannulation with and without the use of intra-procedural CT scanning. METHODS: Retrospective case series including patients who underwent AVS from October 2000 to September 2022. Clinical and laboratory values were abstracted from the electronic medical record. Successful cannulation of the RAV was defined as a selectivity index > 3. RESULTS: 110 patients underwent 124 AVS procedures. Pre-AVS CT imaging was available for 118 AVS procedures. The RAV was identified in 61 (51.7%) CT datasets. Biochemical confirmation of successful RAV cannulation occurred in 98 (79.0%) of 124 AVS procedures. There were 52 (85.2%) procedures in which the RAV was identified on pre-AVS CT and there was biochemical confirmation of successful RAV sampling. Among these 52 procedures, the RAV was localized during AVS at the same anatomic level or within 1 vertebral body level cranial to the level identified on pre-AVS CT in 98.1% of cases. The rate of successful RAV cannulation was higher in patients who underwent intra-procedural CT (93.8% versus 63.9%), P < 0.01. CONCLUSIONS: Pre-AVS and intra-procedural CT images provide an invaluable roadmap that resulted in a higher rate of accurate identification of the RAV and successful AVS procedures; in particular, search for the RAV orifice during AVS can be limited to 1 vertebral body cranial to the level identified on pre-AVS CT imaging and successful cannulation can be confidently verified with intra-procedural CT.

Serendipitous Adrenal Hyperplasia in Patients Admitted to the Emergency Department for Suspected SARS-CoV-2 Infection is Linked to Increased Mortality.

BACKGROUND: Few data are available on adrenal morphology in patients with acute diseases, although it is known that endogenous glucocorticoids are essential for survival under stress conditions and that an adequate response is driven by activation of the hypothalamic-pituitary-adrenal (HPA) axis. AIMS: The aim of this study was to assess adrenal morphology in patients with acute disease compared with patients with non-acute disease. METHODS: This cross-sectional study included: 402 patients admitted to the emergency department (ED) for suspected SARS-CoV-2 infection (March-May, 2020) [main cohort]; 200 patients admitted to the ED for acute conditions (December 2018-February 2019) [control group A]; 200 outpatients who underwent radiological evaluation of non-acute conditions (January-February 2019) [control group B]. Chest and/or abdominal CT scans were reviewed to identify adrenal nodules or hyperplasia. RESULTS: In the main cohort, altered adrenal morphology was found in 24.9% of the patients (15.4% adrenal hyperplasia; 9.5% adrenal nodules). The frequency of adrenal hyperplasia was higher both in the main cohort (15.4%) and control group A (15.5%) compared to control group B (8.5%; p = 0.02 and p = 0.03, respectively). In the main cohort, 14.9% patients died within 30 d. According to a multivariate analysis, adrenal hyperplasia was an independent risk factor for mortality (p = 0.04), as were older age (p <0.001) and active cancer (p = 0.01). CONCLUSIONS: The notable frequency of adrenal hyperplasia in patients with acute diseases suggests an exaggerated activation of the HPA axis due to stressful conditions. The increased risk of short-term mortality found in patients with adrenal hyperplasia suggests that it may be a possible hallmark of worse prognosis.

Adrenal washout CT in patients with no history of cancer: a waste of time?

PURPOSE: To validate the diagnostic performance of adrenal washout CT in patients without known malignancy in a Western Australian population. METHODS: A radiology information system (RIS) search for CT reports containing "adrenal" and "washout" across six networked metropolitan public hospitals between January 2005 and November 2021. Homogenous nodules ≥ 1 cm, ≥ 10 HU without a suspected functional component in patients without a history of malignancy were included. Reported absolute and relative washout percentages were recorded and re-measured from unenhanced, 60-s portal venous and 15-min delayed phase imaging and compared to either histopathological or CT follow up for growth (≥ 12 months) reference standards. RESULTS: 2653 studies were screened with 191 meeting inclusion criteria. 105 nodules underwent washout CT and then had either histopathological (12 patients) or CT follow up (93 patients) reference standards available. Reported absolute washout (aWO) estimated sensitivity and specificity for malignant/indeterminate nodules was low at 33% (95% CI 25-43%) and 77% (95% CI 68-84%) respectively. Reported relative washout (rWO) sensitivity and specificity were 56% (95% CI 46-65%) and 69% (95% CI 60-77%) respectively. Negative predictive values for both aWO and rWO were reassuring at 92% (95% CI 86-96%) and 94% (95%CI 88-97%). CONCLUSION: Our study validates a recent report suggesting that adrenal washout has poor sensitivity for and consequent limited utility to exclude malignancy in patients with no cancer history. However, patients with incidental adrenal nodules < 4 cm in size with benign washout can be reassured by the high negative predictive value and worked up to exclude functional adenoma and re-imaged in a year to confirm no growth.

"Blunt adrenal injury does not affect outcomes in adult patients with isolated abdominal injury - A National Trauma Data Bank review®".

INTRODUCTION: Traumatic blunt adrenal injury (BAI) has been an area of debate, with conflicting data on its impact. BAI from blunt abdominal injury is challenging to diagnose early due to retroperitoneal gland location and minimal clinical signs. The incidence of BAI ranges from 0.03 % to 4.95 %, with an increasing trend attributed to advanced CT imaging. Conflicting data exists regarding BAI's implications on patient outcomes, necessitating a comprehensive evaluation. METHODS: A retrospective review of the National Trauma Data Bank (NTDB®) for 2017-2021 included a total of 352,654 patients with 337,628 polytrauma patients and 15,026 isolated abdominal trauma patients. Patients were categorized into those with and without adrenal injury. Demographic data and outcomes were compared using statistical tests, focusing on Injury Severity Scores (ISS), mortality, length of stay, and ventilation days. RESULTS: Polytrauma patients with BAI had increased mortality, longer ICU and hospital stays, and ventilation requirements when compared to polytrauma patients without BAI. However, when evaluating isolated abdominal trauma patients with BAI showed no significant differences when compared to isolated abdominal trauma without BAI in mortality or ICU LOS and a slight decrease in ICU admissions, hospital LOS, and ventilation requirement. DISCUSSION: The study indicates a significant association between BAI and increased trauma severity among polytrauma patients. Mortality, however, did not exhibit a consistent rise across all patients with adrenal injury, emphasizing that BAI may not independently influence outcomes. These findings align with the notion that adrenal injury is linked to the overall trauma burden rather than being a primary determinant of mortality.

Ultrasonographic measurements of the normal adrenal glands in guinea pigs (Cavia Porcellus).

Hyperadrenocorticism is an uncommon but important endocrine disease in guinea pigs, but due to its subtle clinical signs and the limited information in veterinary literature, it can be underdiagnosed or misdiagnosed. Ultrasound of the adrenal glands in patients with suspected hyperadrenocorticism can help in identifying adrenomegaly. The purpose of this prospective study was to identify ultrasonographic adrenal gland dimensions in presumed healthy guinea pigs using the same standardized method described for dogs and cats. A conscious ultrasound scan was conducted on twenty client-owned, presumed healthy guinea pigs, and their adrenal glands were measured. A possible correlation between adrenal dimensions with age, sex, and body weight was investigated. The mean length, cranial and caudal pole thickness for the left and right adrenal glands were, respectively, 12.64 ± 2.11 mm and 11.55 ± 1.52 mm; 4.83 mm ± 1.03 mm and 4.69 ± 1.34 mm; 4.8 ± 1.23 mm and 4.04 ± 0.75 mm. The thickness of the left caudal pole was significantly higher than the right (P = 0.02). A significant positive correlation was found between the length of the left adrenal gland and both age (r = 0.46; P = .03) and weight (r = 0.59; P = .01). Statistical correlation between the thickness of each cranial and caudal pole, with age, sex, or weight, was not found. The dimensions provided could prove a useful tool in the clinical evaluation of guinea pigs with suspected hyperadrenocorticism.

Retrospective application of a validated algorithm for estimation of adrenal gland volume after computed tomography on 46 dogs undergoing adrenalectomy.

Canine adrenal gland volume can be predicted based on body weight and computed tomography (CT) measurements using a validated algorithm. Use of this algorithm to detect adrenal pathology, including hyperplasia, hypoplasia and neoplasia, in clinical cases has not been described. The objective of this study was to illustrate application of the algorithm by estimating subject-specific adrenal gland volume in a historical cohort of dogs with known adrenal disease. Forty-six dogs that underwent CT and subsequent adrenalectomy were included. Clinical records and CT images from dogs that underwent adrenalectomy and histologic examination of the excised adrenal gland(s) were reviewed. Normal adrenal gland volumes for each dog were estimated using the algorithm, and compared with measured volumes of the affected glands. Linear measurement of the largest lesion diameter was also recorded. Fifty-eight adrenal glands were removed from 46 dogs, with pathology confirmed in all glands. Pathology included 28 adenomas, 13 carcinomas, 11 pheochromocytomas and 6 other benign pathologies. The volume of all removed adrenal glands was measured to be larger than the expected normal volume estimated by the algorithm, ranging from 1.1 to 212.9 times larger than estimated. Adrenal glands with malignant and benign pathology showed variable volumes with overlapping ranges recorded. Assessment of the dimensions of any focal lesion against a cut-off of 20 mm failed to discriminate malignancy. This study illustrates and supports the application of a validated volumetric algorithm for estimation of subject-specific adrenal gland volume to identify the presence of pathology and as a tool to assist clinical decision-making.

Clinical characteristics and outcomes of adrenal hemorrhage.

BACKGROUND: Although uncommon, adrenal hemorrhage has multiple etiologies. Because clinical characteristics, management, and outcomes of patients with adrenal hemorrhage are inadequately described, we examined the underlying etiology, need for intervention, evolution of imaging characteristics, and adequacy of subsequent evaluation. METHODS: We performed a retrospective review of patients diagnosed with adrenal hemorrhage (radiologist-confirmed density consistent with hemorrhage on computed tomography) from 2005 to 2021 at a university-based institution. Demographic characteristics, hemorrhage etiology, and subsequent follow-up were analyzed. RESULTS: Of 193 adrenal hemorrhage patients, the mean age was 49.2 ± 18.3 years, and 35% were female. Clinical presentations included trauma (47%), abdominal or flank pain (28%), incidental findings on imaging acquired for other reasons (12%), postoperative complication (8%), or shock (3%). Hemorrhage outside of the gland was present in 62% of patients. Unilateral hemorrhage was more frequent (93%) than bilateral (7%). A total of 12% of patients had nodules, but only 70% of these were identified on initial imaging, and only 43% had hormonal evaluation. Of 7 patients who had adrenalectomy or biopsy, pathology was either benign (57%) or nonadrenal malignancy (43%). No adrenocortical carcinomas were identified. Follow-up imaging was performed in 56% of patients and revealed decreased, stable, resolved, or increased adrenal hemorrhage size in 39%, 19%, 30%, and 12% of patients, respectively. CONCLUSION: Adrenal hemorrhage is secondary to multiple etiologies, most commonly trauma. In the setting of adrenal hemorrhage, many adrenal nodules were not identified on initial imaging. Only a minority of patients with nodules underwent "complete" biochemical evaluation. Follow-up imaging may improve the identification of underlying nodules needing hormonal evaluation.

Adrenal Vein Sampling: Tips and Tricks.

Adrenal vein sampling (AVS) is the standard method for distinguishing unilateral from bilateral sources of autonomous aldosterone production in patients with primary aldosteronism. This procedure has been performed at limited specialized centers due to its technical complexity. With recent advances in imaging technology and knowledge of adrenal vein anatomy in parallel with the development of adjunctive techniques, AVS has become easier to perform, even at nonspecialized centers. Although rare, anatomic variants of the adrenal veins can cause sampling failure or misinterpretation of the sampling results. The inferior accessory hepatic vein and the inferior emissary vein are useful anatomic landmarks for right adrenal vein cannulation, which is the most difficult and crucial step in AVS. Meticulous assessment of adrenal vein anatomy on multidetector CT images and the use of a catheter suitable for the anatomy are crucial for adrenal vein cannulation. Adjunctive techniques such as intraprocedural cortisol assay, cone-beam CT, and coaxial guidewire-catheter techniques are useful tools to confirm right adrenal vein cannulation or to troubleshoot difficult blood sampling. Interventional radiologists should be involved in interpreting the sampling results because technical factors may affect the results. In rare instances, bilateral adrenal suppression, in which aldosterone-to-cortisol ratios of both adrenal glands are lower than that of the inferior vena cava, can be encountered. Repeat sampling may be necessary in this situation. Collaboration with endocrinology and laboratory medicine services is of great importance to optimize the quality of the samples and for smooth and successful operation. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Feasibility Study of Single-Photon Emission Computed Tomography with Iodine-123 Labeled Metaiodobenzylguanidine for Preclinical Evaluation of Labetalol as a ß-Adrenergic Receptor Blocker.

Among clinically used radiopharmaceuticals, iodine-123 labeled metaiodobenzylguanidine ([123I]mIBG) serves for diagnosing neuroendocrine tumors and obtaining images of myocardial sympathetic innervation. mIBG, a structural analogue of norepinephrine (NE), a neurotransmitter acting in peripheral and central nerves, follows a pathway similar to NE, transmitting signals through the NE transporter (NET) located at synaptic terminals. It moves through the body without decomposing, enabling noninvasive image evaluation. In this study, we aimed to quantify [123I]mIBG uptake in the adrenal glands using small animal single-photon emission computed tomography/computed tomography (SPECT/CT) images post [123I]mIBG administration. We investigated the possibility of assessing the effectiveness of ß-adrenergic receptor blockers by quantifying SPECT/CT images and biodistribution results to determine the degree of [123I]mIBG uptake in the adrenal glands treated with labetalol, a known ß-adrenergic receptor blocker. Upon intravenous administration of [123I]mIBG to mice, SPECT/CT images were acquired over time to confirm the in vivo distribution pattern, revealing a clear uptake in the adrenal glands. Labetalol inhibited the uptake of [123I]mIBG in cell lines expressing NET. A decrease in [123I]mIBG uptake in the adrenal glands was observed in the labetalol-treated group compared with the normal group through SPECT/CT imaging and biodistribution studies. These results demonstrate that SPECT/CT imaging with [123I]mIBG could be applicable for evaluating the preclinical efficacy of new antihypertensive drug candidates such as labetalol, a ß-adrenergic receptor blocker.