The Growing Clinical Dilemma of the Adrenal Incidentaloma

The term "adrenal incidentaloma" refers to the serendipitous discovery of an adrenal lesion during imaging performed for unrelated indications. This has become a pervasive clinical challenge, with such lesions identified in up to 5% of all cross-sectional abdominal examinations. This prevalence is not static; it demonstrates a clear correlation with age, rising from 0.14% in young adults to as high as 7% in patients over the age of 70 [1]. The increasing frequency of this finding is a direct consequence of the widespread adoption and technological advancement of imaging modalities, particularly multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI) [4].

The clinical dilemma posed by an incidentaloma is significant. The vast majority, approximately 70-80%, are benign, non-functioning adrenal adenomas that require no intervention [18].  However, a critical minority represent pathologies that demand immediate and specific management pathways. These include malignant entities such as metastases or the rare but aggressive adrenocortical carcinoma (ACC), and hormonally active tumors like pheochromocytoma (PCC) or aldosterone-producing adenomas, which can cause severe systemic disease [5]. Therefore, accurate and non-invasive characterization is paramount. A definitive diagnosis of a benign lesion can alleviate patient anxiety and obviate the need for costly serial imaging or invasive procedures like percutaneous biopsy. Conversely, mischaracterizing a malignant or functional lesion can lead to catastrophic delays in treatment, profoundly impacting patient prognosis [10].

The Central Role of Computed Tomography in Adrenal Characterization

Computed tomography remains the cornerstone of adrenal imaging. Its high spatial resolution, rapid acquisition times, widespread availability, and well-established diagnostic criteria make it the primary modality for the initial evaluation of an adrenal mass [16]. The initial and most specific step in CT characterization is the unenhanced acquisition. The presence of significant intracellular lipid is a hallmark of benign adrenal adenomas [12]. This lipid content lowers the lesion's density, and an attenuation value of 10 Hounsfield Units (HU) or less on unenhanced CT is considered a highly reliable diagnostic criterion for a lipid-rich adenoma. This simple measurement carries an exceptional specificity of 98%, often providing a definitive diagnosis without the need for further imaging [11].

The Diagnostic Challenge: Lipid-Poor Adenomas and the Rationale for Quantitative Imaging

The primary diagnostic challenge arises with the approximately 30% of adrenal adenomas that are "lipid-poor". These lesions contain insufficient intracellular fat to meet the ≤10 HU criterion, exhibiting unenhanced attenuation values greater than 10 HU. Radiologically, they are indeterminate and can have an appearance that overlaps significantly with more sinister pathologies, particularly metastases or pheochromocytomas [15]. This diagnostic ambiguity necessitates a more advanced, functional assessment of the lesion's vascular properties, for which dynamic contrast-enhanced CT (CECT) with washout analysis was developed [2].

The principle of washout analysis is rooted in the distinct hemodynamics of different adrenal lesions. Benign adenomas are supplied by a network of specialized capillaries that allow for rapid uptake of intravenous contrast material, followed by a similarly rapid clearance or "washout" [8].  In contrast, malignant lesions and pheochromocytomas are typically hypervascular, characterized by disorganized neovascularity and leaky capillaries, which cause them to retain contrast for a longer period. By quantifying the rate at which a lesion clears contrast between a portal venous phase and a delayed phase, its underlying nature can be inferred. The established quantitative metrics for this assessment are the Absolute Percentage Washout (APW) and the Relative Percentage Washout (RPW). An APW of 60% or greater, or an RPW of 40% or greater, is diagnostic for a benign adenoma. The timing of the delayed scan is a critical protocol parameter; a 15-minute delay has been shown to provide higher diagnostic accuracy than shorter intervals, such as 10 minutes, which may yield indeterminate results [17].

Aims and Objectives

Primary Aim

The primary aim of this study was to assess the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall accuracy of a dedicated triphasic, contrast-enhanced quantitative CT protocol in the characterization of adrenal masses.

Secondary Objectives

The secondary objectives were:

1. To correctly identify and diagnose adrenal tumors radiologically based on established quantitative criteria, including unenhanced attenuation and calculated percentage washout values.
2. To rigorously associate the radiological findings with definitive histopathological examination results, thereby validating the imaging protocol against the undisputed gold standard of tissue diagnosis.
3. To demonstrate the role of precise CT characterization in guiding subsequent multidisciplinary management, including triaging patients for minimally invasive interventional radiology procedures such as percutaneous biopsy, adrenal vein sampling, or tumor ablation

Study Design, Setting, and Ethical Compliance

This investigation was conducted as a hospital-based, observational study. The study enrolled a consecutive series of 42 patients who presented with adrenal masses to the Department of Radio-Diagnosis at Mahatma Gandhi Medical College and Hospital, Jaipur. The study protocol was designed in accordance with institutional guidelines and received full approval from the Institutional Ethical Committee. Prior to enrollment, the study's purpose and procedures were explained to all participants, and written informed consent was obtained from each individual.

Inclusion and Exclusion Criteria

All patients presenting with symptoms suggestive of an adrenal mass or those with a previously identified adrenal mass on other imaging modalities were eligible for inclusion in the study. Exclusion criteria were established to ensure patient safety and data integrity. These included pregnant females, critically ill patients who could not tolerate the procedure, individuals with a known history of severe hypersensitivity or anaphylactic reaction to iodinated contrast media, and patients with significantly impaired renal function, defined as an estimated Glomerular Filtration Rate (eGFR) of less than 30 mL/min/1.73 m²

Tri-phasic Adrenal CT Protocol: Acquisition Parameters

All CT examinations were performed on a GE 128-slice Multidetector CT (MDCT) scanner, ensuring consistency in image acquisition technology. A standardized triphasic adrenal protocol was mandated for all participants.

For contrast-enhanced phases, 100 mL of a non-ionic iodinated contrast medium (350 mg Iodine/mL) was administered intravenously using a power injector at a controlled rate of 3-4 mL/sec. The protocol consisted of three distinct acquisition phases:

1. Unenhanced Phase (UCT): An initial scan performed before contrast administration to establish the baseline attenuation of the adrenal mass in Hounsfield Units (HU).
2. Portal Venous Phase (PVP): Acquired 65 to 70 seconds after the initiation of the contrast injection to capture peak parenchymal and lesion enhancement.
3. Delayed Phase (DP): Acquired precisely 15 minutes after the start of the contrast injection to assess for contrast washout. This 15-minute delay was specifically chosen to maximize diagnostic accuracy for lipid-poor adenomas, as supported by literature indicating superior performance compared to shorter delay times [17]

Quantitative Image Analysis: ROI Placement and Washout Calculations

Image analysis was performed on a dedicated workstation. To ensure measurement accuracy and reproducibility, a standardized method for placing the region of interest (ROI) was employed. An elliptical ROI was drawn to encompass at least 50% to two-thirds of the lesion's maximum cross-sectional area. Crucially, care was taken to avoid including areas of gross calcification, cystic degeneration, or central necrosis within the ROI, as these components do not enhance and could artificially lower the measured attenuation, confounding the washout calculations.

Using the mean attenuation values (in HU) obtained from the ROI in each of the three phases, the washout percentages were calculated according to the following standard formulae:

• Absolute Percentage Washout (APW): This metric requires data from all three phases. A value of ≥60% was considered diagnostic for a benign adenoma.

Absolute washout:

Enhanced CT (HU) – Delayed CT (HU) X 100

Enhanced CT (HU)- Unenhanced CT

• Relative Percentage Washout (RPW): This metric is used when an unenhanced scan is not available, though it was calculated for all patients in this study. A value of ≥40% was used as the criterion for a benign adenoma.

Relative washout:

Enhanced CT (HU) – Delayed CT (HU) X 100

Enhanced CT (HU)

Histopathological Correlation and Gold Standard

The definitive diagnosis for 34 of the 42 patients was established through histopathological analysis of tissue specimens. These specimens were obtained from either image-guided percutaneous biopsy or surgical resection of the adrenal mass. This pathological diagnosis served as the unequivocal gold standard against which the performance of the quantitative CT protocol was evaluated. For the remaining 8 patients, a definitive pathological diagnosis was not available at the time of study completion.

Statistical Analysis

All collected data were systematically entered into an Excel spreadsheet for management and analysis. The diagnostic efficacy of the CT protocol was evaluated for the 34 cases with histopathological correlation. Standard metrics including sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall accuracy were calculated. A p-value of less than 0.01 was set as the threshold for statistical significance.

Demographic and Clinical Profile of the Study Cohort

The study cohort comprised 42 patients, with a slight female predominance (n=22, 52.4%) compared to males (n=20, 47.6%). The mean age of the patients was 48.2 years, with the age distribution showing a notable peak in the elderly population; 33.3% (n=14) of participants were over 60 years of age.

Figure 1: Gender Distribution of Patient Cohort (N=42). This shows a slight female predominance (52.4%) in the study population.

Figure 2: Age Distribution of Patient Cohort. The histogram shows the number of patients in different age categories, highlighting a bimodal tendency with peaks in middle-aged and elderly populations

The most frequently reported presenting complaint was abdominal pain, noted in 38.1% (n=16) of patients. This was followed by hypertension, which was the chief complaint in 16.7% (n=7) of cases. A significant portion of the cohort (n=11, 26.2%) had a pre-existing medical history of hypertension.

Figure 3: Presenting Complaints of Study Subjects. This displays the frequency of various symptoms at presentation, underscoring the predominance of abdominal pain and hypertension.

Electrolyte analysis revealed that hyponatremia was the most common imbalance, present in 16.7% of patients, followed by hyperkalemia, hyperchloremia, and hypochloremia, each affecting 4.8% of the cohort.

Morphological and Radiologic Characteristics of Adrenal Masses

Analysis of the adrenal masses revealed a predilection for the right adrenal gland, with 57.1% (n=24) of lesions located on the right side. The mean size of the lesions was 4.65 cm, with 42.9% (n=18) measuring greater than 4 cm, a feature that raises suspicion for malignancy. The vast majority of lesions (n=41, 87.6%) demonstrated well-defined margins. Post-contrast enhancement patterns were heterogeneous, with mixed enhancement being the most common pattern observed in 50.0% (n=21) of cases.

Figure 4: Distribution of Adrenal Lesion Size. The histogram demonstrates the frequency of lesions across different size categories, with a significant proportion (42.9%) being larger than 4 cm.

Quantitative CT Analysis and Radiological Diagnosis

Based on the application of quantitative washout criteria (APW ≥60% and RPW ≥40%), 14 lesions (33.3%) were radiologically classified as benign adenomas, while the remaining 28 lesions (66.7%) were classified as non-adenomas, warranting further investigation or definitive management.

The final radiological diagnoses rendered after full qualitative and quantitative assessment were diverse. Adenoma was the most common radiological diagnosis (31.0%), followed by pheochromocytoma (21.4%) and myelolipoma (14.3%).

Figure 5: Frequency of Final CT Diagnoses. This displays the variety of diagnoses made radiologically, with adenoma and pheochromocytoma being the most frequent.

Histopathological Correlation

The histopathological analysis, performed on 34 of the 42 cases, revealed a complex and high-risk distribution of pathologies. The most common confirmed diagnosis was Adrenal Cortical Adenoma (n=11, 26.2%). However, a substantial number of cases were functional or malignant tumors, including Pheochromocytoma (n=9, 21.4%), Adrenal Cortical Carcinoma (n=3, 7.1%), and others.

Figure 6: Quantitative CECT washout Metrics. This visualizes the clear separation in washout characteristics, enabling confident diagnosis.

Diagnostic Performance of Quantitative CT Washout Criteria

The tri-phasic quantitative CT protocol demonstrated exceptional diagnostic performance in the 34 cases with definitive histopathological correlation. When used to differentiate benign from non-benign (malignant, functional, or other) pathologies, the protocol achieved a sensitivity of 94.0%, specificity of 100.0%, and PPV of 100.0%. The results were statistically significant, confirming the protocol's high degree of reliability.

Illustrative Case Series

The following cases from the study cohort demonstrate the practical application and diagnostic utility of the tri-phasic quantitative CT protocol.

Case 1: Adrenocortical Carcinoma (ACC)

A patient presented with a large, heterogeneous right adrenal mass. The unenhanced CT demonstrated a mean attenuation of 49 HU. Following contrast administration, the lesion enhanced to 65 HU in the venous phase and retained contrast in the delayed phase with an attenuation of 60 HU. The calculated Absolute Percentage Washout (APW) was 31.3%, well below the 60% threshold for a benign adenoma. This poor washout correctly identified the lesion as a non-adenoma. Subsequent histopathological analysis confirmed the diagnosis of Adrenocortical Carcinoma.

Case 2: Pheochromocytoma (PCC)

A patient was found to have a left adrenal mass with an unenhanced attenuation of 47 HU. The lesion showed intense, avid enhancement in the venous phase, reaching 108 HU, and remained dense in the delayed phase at 97 HU. The calculated APW was only 18%, far below the benign threshold. This quantitative finding, combined with the qualitative feature of avid enhancement, strongly suggested a pheochromocytoma, which was confirmed on pathology.

Case 3: Adrenal Histoplasmosis (Granulomatous Disease)

An unusual case involved a right adrenal mass with an unenhanced HU of 49. It enhanced to 63 HU in the venous phase and showed paradoxical increased density in the delayed phase at 66 HU, resulting in a negative washout. This pattern correctly flagged the lesion as a non-adenoma. Histopathology revealed a rare infectious etiology: adrenal histoplasmosis, a form of granulomatous disease.

Case 4: Myelolipoma

A patient presented with a right adrenal mass that demonstrated areas of macroscopic fat on the unenhanced CT scan, with attenuation values measuring -70 HU. The presence of macroscopic fat is pathognomonic for myelolipoma, providing a definitive diagnosis on the unenhanced scan alone and obviating the need for contrast administration or washout calculation.

Case 5: Adrenal Hematoma

A patient with a history of trauma presented with a right adrenal mass. The unenhanced CT showed a hyperdense lesion with an attenuation of 67 HU. It enhanced to 75 HU in the venous phase and remained dense at 74 HU in the delayed phase. The calculated APW was only 12.5%, correctly identifying it as a non-adenoma and consistent with a hematoma in the clinical context.

Interpretation of High Diagnostic Accuracy in a Clinically High-Risk Cohort

The most striking finding of this investigation is the 100% specificity and 100% positive predictive value achieved by the quantitative CT protocol. In the context of adrenal mass characterization, this level of performance is clinically profound. It signifies that within this study cohort, the protocol made no false-positive errors; every single lesion that was radiologically classified as a non-adenoma based on washout criteria was subsequently confirmed as a non-adenoma by the gold standard of histopathology. This establishes an exceptionally high level of confidence in the test's ability to "rule in" concerning pathology.

This performance is particularly noteworthy given the composition of the study group. With a mean lesion size of 4.65 cm and nearly 43% of masses exceeding the 4 cm threshold for malignancy suspicion, the cohort had a significantly higher pre-test probability of malignancy and functional tumors compared to a typical screening population of incidentalomas. The histopathological results confirmed this, with a high prevalence of pheochromocytoma (21.4%) and various malignancies (approximately 15% combined). Validating a diagnostic test against such a challenging, high-risk population strengthens its clinical applicability. It demonstrates that the established quantitative thresholds are robust enough to maintain their discriminatory power even when the baseline probability of disease is high.

Validation of the 15-Minute Delayed Protocol for Differentiating Adenomas

The successful outcomes of this study underscore the critical importance of adhering to a strict, standardized imaging protocol. The deliberate choice of a 15-minute delayed phase is a key methodological strength. Existing literature indicates that shorter delay times, such as 10 minutes, may yield lower diagnostic accuracy and a higher rate of indeterminate results, particularly for lipid-poor adenomas. This study provides robust, real-world evidence that the longer delay allows for a more complete and accurate assessment of contrast clearance, maximizing the separation between the washout curves of adenomas and non-adenomas [17]

Furthermore, the study's methodology emphasized meticulous ROI placement, mandating coverage of a large portion of the lesion while actively avoiding areas of heterogeneity like necrosis or calcification. This technical detail is paramount for mitigating the impact of image noise and measurement variability, which are known pitfalls in quantitative imaging [3]. The high accuracy achieved in this study serves as a practical validation of these technical recommendations, demonstrating that with rigorous technique, CT washout analysis can be a highly reproducible and reliable diagnostic tool.

Navigating Differential Diagnoses: Imaging Signatures beyond Washout

While quantitative washout is the primary tool for indeterminate lesions, a comprehensive radiological assessment incorporates all available imaging features. The data from this cohort provides an excellent platform for discussing the nuanced differentiation of key adrenal pathologies.

• Pheochromocytoma: The high prevalence of PCC (21.4%) in this study is a major finding. While a subset of PCCs can exhibit rapid washout that overlaps with adenomas, they often possess other distinguishing characteristics [15]. These include a high unenhanced attenuation (mean of 35.6 HU in some studies), intense and avid contrast enhancement (often >110 HU), and a tendency for cystic or hemorrhagic changes, creating a heterogeneous appearance [9]. The case series from this study visually confirms this pattern of avid enhancement and poor washout. A diagnosis of PCC must always be considered in a hypervascular adrenal mass, regardless of washout, and should prompt immediate biochemical correlation [6].
• Adrenocortical Carcinoma (ACC): The ACC cases in this study aligned with the classic imaging descriptions. These tumors are typically large (98% are >4 cm), heterogeneous, and often contain areas of necrosis, calcification, and hemorrhage. They characteristically demonstrate poor contrast washout and may show signs of local invasion or venous extension, particularly into the inferior vena cava [7].
• Metastases: Adrenal metastases are frequently bilateral, display irregular margins, and typically show poor washout kinetics [14]. However, a well-known diagnostic pitfall is the hypervascular metastasis, such as from renal cell carcinoma or hepatocellular carcinoma, which can exhibit accelerated washout and mimic a benign adenoma [4]. The 100% specificity achieved in this study suggests that this particular pitfall was not a confounding factor in this specific cohort, but it remains a critical point of awareness for radiologists. The clinical context of a known primary malignancy is invaluable in these cases [13].

Implications, Limitations, and Future Research

Clinical Implications for Patient Management and Triage

The primary implication of this study's findings is the powerful validation of the tri-phasic CECT protocol as a highly reliable "rule-in" test for concerning adrenal pathology. The 100% PPV observed transforms the role of the radiologist from a mere diagnostician to a pivotal manager of the clinical pathway. A CT report that classifies a lesion as a "non-adenoma" based on these validated quantitative criteria is not just an interpretation; it becomes a high-confidence trigger for a specific and immediate clinical action. This evidence-based certainty allows the multidisciplinary team of endocrinologists, surgeons, and interventional radiologists to act decisively.

The Diagnostic-Therapeutic Bridge: Guiding Interventional Radiology Pathways

The ultimate value of high-fidelity quantitative imaging lies in its capacity to serve as a diagnostic-therapeutic bridge, seamlessly triaging patients toward the appropriate specialized management pathway. The CT report, when grounded in such robust data, becomes more than an interpretation; it becomes a roadmap for the multidisciplinary team, particularly for guiding complex and high-stakes Interventional Radiology (IR) procedures.

Adrenal Vein Sampling (AVS) for Primary Aldosteronism

In patients presenting with treatment-resistant hypertension and biochemical evidence of Primary Aldosteronism (PA), CT imaging is the first step. If the CT is inconclusive, demonstrates bilateral nodularity, or shows a small unilateral nodule, a definitive radiological classification of "non-adenoma" based on washout confidently triggers the need for Adrenal Vein Sampling (AVS). AVS is the mandatory diagnostic IR procedure to lateralize the source of aldosterone hypersecretion. The ultimate decision to proceed to either curative unilateral adrenalectomy or lifelong medical management hinges entirely on the success of this procedure. AVS is technically demanding, requiring extreme skill, particularly due to the highly variable and challenging anatomy of the right adrenal vein. Successful cannulation must be confirmed via calculation of the Selectivity Index (SI ≥ 2.0 unstimulated), followed by computation of the Lateralization Index (LI ≥ 4.0 stimulated) to definitively guide surgical planning.

Percutaneous Ablation (RFA, Cryoablation, MWA)

For functioning tumors (such as the high prevalence of PCC in this study) or for small, isolated metastases in patients who are unsuitable for surgery due to comorbidities, percutaneous ablation offers an effective, minimally invasive treatment option. The radiological classification of a mass as a suspected PCC triggers a mandatory and critical pre-procedural IR safety protocol to mitigate the risk of a life-threatening intra-procedural hypertensive crisis. This protocol is a direct, non-negotiable consequence of the imaging diagnosis and necessitates close multidisciplinary coordination. It involves several weeks of pharmacological preparation, including alpha-adrenergic blockade (e.g., phenoxybenzamine) to control blood pressure, followed by beta-adrenergic blockade to control tachycardia. Beta-blockade must never be initiated alone, as this can lead to unopposed alpha-stimulation and a paradoxical hypertensive emergency. Furthermore, the IR procedure itself requires precise techniques, such as hydro-dissection (the injection of fluid to create a safe space), to protect adjacent organs like the pancreas, bowel, or diaphragm from thermal injury during ablation.

Trans-Arterial Embolization (TAE) for Hemorrhagic Crises

The study cohort included adrenal hematomas and myelo-lipomas, the latter of which, while benign, are vascular and can lead to life-threatening spontaneous retroperitoneal hemorrhage.¹ In this acute scenario, the role of CT shifts from elective diagnosis to emergency triage. When CECT identifies active contrast extravasation from a ruptured adrenal mass, the procedure shifts from diagnostic characterization to emergency IR management via Trans-Arterial Embolization (TAE). TAE serves the vital role of achieving immediate hemostasis and hemodynamic stabilization in a critically ill patient. This procedure demands that the interventional radiologist possess detailed anatomical knowledge of the complex and highly variable trifurcated adrenal arterial supply which arises from the Inferior Phrenic Artery, the Aorta, and the Renal Artery to ensure super-selective catheterization and deployment of embolic agents to stop the bleeding, while preventing catastrophic non-target embolization to other organs.

A Proposed Algorithm for Integrated Adrenal Mass Management

The synthesis of this study's findings and their clinical implications can be distilled into a practical, stepwise algorithm. This algorithm integrates high-accuracy CECT features to guide definitive patient management, illustrating the clinical impact of precise quantitative diagnosis in a modern, multidisciplinary setting.

The Bridge to Intervention: A Multidisciplinary Approach

Table 9: Quantitative CT Triage and Adrenal Mass Management Algorithm

Study Limitations

Despite the strong findings, this study has several limitations that must be acknowledged:

• Sample Size: The study cohort of 42 patients, with histopathological correlation available for 34, is relatively small. Validation in a larger, multi-center prospective study would strengthen the findings.
• Selection Bias: As a hospital-based study at a tertiary referral center, the cohort is skewed towards more complex, symptomatic, and larger lesions. The prevalence of malignancy and pheochromocytoma is significantly higher than in a general population of incidentalomas. Consequently, the exceptional specificity and PPV may not be fully generalizable to a low-risk, asymptomatic screening population.
• Incomplete Follow-up: Histopathological correlation was not available for 8 of the 42 patients. Their exclusion from the final statistical analysis means the performance metrics are based on a subset of the total enrolled population.
• Reader Experience: The image interpretations were likely performed by radiologists with specialized expertise. The reproducibility of these quantitative measurements in a general community practice setting is unknown.

6.5 Directions for Future Research

This study provides a strong foundation for future research aimed at further refining the non-invasive characterization of adrenal masses.

• Advanced CT Technologies: Future investigations should focus on the role of dual-energy CT, which can generate "virtual non-contrast" images to reduce radiation dose, and photon-counting CT, which offers superior spatial and contrast resolution.
• Advanced MRI Techniques: Further research into the utility of advanced techniques like Diffusion-Weighted Imaging (DWI) and Magnetic Resonance Spectroscopy (MRS) is warranted to resolve cases that remain indeterminate on CT.
• Radiomics and Artificial Intelligence (AI): AI and machine learning algorithms can analyze complex texture patterns imperceptible to the human eye and have shown promise in differentiating between benign and malignant adrenal lesions with high accuracy.
• Integration with Interventional Pathways: There is a need for more research that formally links quantitative CT findings to the outcomes of specific interventional radiology procedures, such as predicting the success of percutaneous ablation or the risk of hemorrhage during trans-arterial embolization (TAE), creating more sophisticated, evidence-based "image-to-intervention" pathways.

This study validates that a meticulously executed triphasic adrenal CECT protocol, incorporating quantitative washout analysis with a 15-minute delay, is an exceptionally accurate and reliable non-invasive tool for the characterization of adrenal masses. Demonstrating 100% specificity and 100% positive predictive value in a clinically high-risk cohort, the protocol functions as a definitive diagnostic gatekeeper. It confidently identifies lesions that require further invasive management including specialized interventional radiology procedures while safely and effectively excluding benign adenomas from an unnecessary and costly diagnostic workup. These findings reinforce the central and indispensable role of quantitative CT in modern, multidisciplinary adrenal care pathways, effectively bridging the gap between diagnostic imaging and decisive clinical action.

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