Difficulties in the prospective diagnosis of functional adrenal diseases by CT

The accuracy of prospective diagnosis of functional adrenal disorders by computed tomography (CT) was evaluated in 65 patients strongly suspected of having such disorders. Thirty-seven patients also underwent adrenal venography and selective adrenal venous sampling. Of the 65 patients, 21 had a hyperfunctioning cortical adenoma, 25 had cortical or medullary hyperplasia, and 11 pheochromocytoma, while 10 had no functional adrenal disease. Diagnosis by CT alone was correct in 66%; diagnosis by CT and venous sampling was correct in 89%. Incorrect prospective CT diagnosis resulted most often from a normal appearance of functionally hyperplastic glands (9 cases), nodular hyperplasia simulating a focal adenoma (8 cases), or an incidental nonfunctioning mass (3 cases). This study emphasizes the need to correlate CT findings with biochemical evaluation and the usefulness of venous sampling in selected cases to avoid inappropriate surgery. When CT is interpreted in correlation with complete biochemical analysis, correct diagnosis can usually be made. A small number of cases may still require adrenal venous sampling.     

The detection of adrenal tumors and hyperplasia in patients with primary aldosteronism: comparison of scintigraphy, CT, and MR imaging

We retrospectively reviewed the imaging studies in 17 proved cases of primary aldosteronism to determine the value of the procedures used to detect adrenal tumors or adrenal hyperplasia. The procedures included CT with 3-, 5-, and/or 10-mm-thick sections (17 patients), 131I-6 beta-iodomethyl-19-norcholesterol (NP-59) scintigraphy (16 patients), and MR imaging (six patients). Proof of the adrenal abnormality was established in cases of tumor (seven adenomas, one carcinoma) by surgery and in cases of adrenal hyperplasia by surgery (three cases); venous sampling (three cases); or combined clinical, biochemical, and imaging data (three cases). Both CT and scintigraphy detected six of the seven adenomas and the adrenal carcinoma (88%). Regarding hyperplasia, CT was correct in five of six and scintigraphy was correct in two of four cases proved by surgery or venous sampling. CT and NP-59 were concordant and suggested the diagnosis of hyperplasia in the remaining three cases without surgical or venous sampling proof. MR detected both cases of adenoma in which it was performed and showed evidence of hyperplasia in one of the four cases of hyperplasia in which it was performed. Although the number of patients in this series is too small to have much statistical power, these results suggest that CT and NP-59 scintigraphy are equivalent in the detection of adrenal abnormalities in patients with primary aldosteronism. The value of MR in the detection of small adrenal contour abnormalities was limited by slice thickness capabilities.     

Distinction between hyperaldosteronism due to bilateral hyperplasia and unilateral aldosteronoma: reliability of CT.

Hyperaldosteronism due to a unilateral adenoma must be distinguished from hyperaldosteronism due to bilateral hyperplasia to enable the proper choice between surgical treatment (for adenoma) or medical treatment (for hyperplasia). To compare the efficacy of computed tomography (CT) and adrenal venous sampling, both examinations were performed in 24 patients with primary aldosteronism. All patients with a diagnosis of adenoma based on findings at venous sampling underwent adrenalectomy. The CT-based diagnosis was unilateral aldosteronoma in 17 patients and hyperplasia in seven patients. On the basis of venous sampling, unilateral adenoma was diagnosed in 22 patients; this diagnosis was confirmed by means of unilateral adrenalectomy in 21 patients. The most common error was diagnosis of hyperplasia based on the presence of bilateral nodules on CT scans: In six of seven patients with such a diagnosis, venous sampling and subsequent surgery revealed a unilateral adenoma. In hyperaldosteronism with multiple bilateral nodules, CT cannot reliably permit distinction between hyperplasia and adenoma.     

Primary hyperaldosteronism: comparison of CT, adrenal venography, and venous sampling

Twenty-nine patients with primary hyperaldosteronism were evaluated with computed tomography (CT), adrenal venous sampling, and adrenal venography. Twenty-three patients had aldosteronomas and six had bilateral adrenocortical hyperplasia. Sixteen (70%) of the adenomas were accurately located by CT. All nodules of 1.5 cm or larger diameter and 50% of nodules 1.0-1.4 cm in diameter were demonstrated. Nodules of less than 1.0 cm in diameter generally were not detected. High-resolution CT appeared more sensitive than standard CT (75% vs. 58%). Adrenal venous sampling for aldosterone assay was the most sensitive of the three methods, localizing 22 (96%) of the 23 adenomas. Eighteen (78%) of the adenomas were identified by adrenal venography, although two patients with bilateral cortical hyperplasia were mistakenly diagnosed as having a small adenoma. No such false-positive studies were encountered with CT or adrenal venous sampling.     

Diagnosis of primary hyperaldosteronism: importance of correlating CT findings with endocrinologic studies.

Twenty patients with primary hyperaldosteronism had endocrinologic and radiologic studies to distinguish aldosterone-producing adenoma from idiopathic hyperaldosteronism due to bilateral micro- or macronodular hyperplasia of the adrenal cortex. In addition to examination for changes in the plasma level of aldosterone associated with postural changes and measurement of the plasma level of 18-hydroxycorticosterone, all 20 patients had CT examination of the adrenal glands. In three patients with normal adrenal glands on CT and three patients with CT evidence of two solitary nodules, one in each adrenal gland, a diagnosis of idiopathic hyperaldosteronism was confirmed by endocrinologic findings (five patients) or 131I-6 beta-iodomethyl-19-norcholesterol (NP-59) adrenal scintigraphy (one patient). In nine patients with a solitary adrenal nodule on CT, a diagnosis of aldosterone-producing adenoma was confirmed by surgery (seven patients) or hormone sampling via the adrenal veins (two patients). However, in three patients with a solitary adrenal nodule on CT, a diagnosis of idiopathic hyperaldosteronism was suggested by endocrinologic findings (three patients) and confirmed by the results of NP-59 scintigraphy (two patients) or adrenal venous sampling (one patient). In addition, in two patients with CT evidence of three adrenal nodules (two in one gland, one in contralateral gland), a diagnosis of aldosterone-producing adenoma was suggested by endocrinologic findings in both patients and confirmed by surgery in one. Although high-resolution CT is highly accurate for the detection of aldosterone-producing adenoma, significant diagnostic errors can occur in patients with primary hyperaldosteronism if CT findings are not correlated with results of endocrinologic studies.     

Diagnostic performance of CT versus MR in detecting aldosterone-producing adenoma in primary hyperaldosteronism (Conn’s syndrome)

The aim of the present study is to compare the diagnostic performance of CT and MR imaging in detecting aldosterone-producing adenoma and to compare the interobserver variability in the detection of an aldosterone-producing adenoma on CT and MR. A retrospective study of 34 patients with primary hyperaldosteronism was performed. A total of 17 cases of aldosterone-producing adenoma and 17 cases of bilateral adrenal hyperplasia were included. The final diagnosis of an adenoma was made by surgery with histological confirmation, whereas that of bilateral adrenal hyperplasia was made on adrenal venous sampling or a good biochemical and clinical response following medical treatment alone and in the absence of a unilateral radiological abnormality. The CT (n=30) and MR (n=24) scans were reviewed independently by two radiologists experienced in adrenal imaging, who were unaware of the cause of the primary hyperaldosteronism. The diagnostic performances of both observers in detecting an aldosterone-producing adenoma on CT and MR imaging were compared. The 16 adenomatous nodules that were detected on imaging ranged from 1 to 4.75 cm in diameter. The calculated sensitivity and specificity for detecting aldosterone-producing adenoma were 87 and 93% for one observer and 85 and 82% for the other observer on CT, and 83 and 83% for one observer and 92 and 92% for the other observer on MR, respectively. Receptor operating characteristics curve analysis showed similar performances of both observers in detecting an aldosterone-producing adenoma on CT and MR imaging. There was good interobserver agreement on CT (k=0.71) and on MR (k=0.67). We have demonstrated comparable diagnostic performance and good interobserver agreement on CT and MR imaging for the detection of aldosterone-producing adenoma.     

肾上腺皮质结节性增生与皮质腺瘤的CT鉴别诊断

目的:探讨肾上腺皮质结节性增生与肾上腺皮质腺瘤的CT鉴别诊断.方法:回顾性统计分析31例肾上腺皮质结节性增生与35例肾上腺皮质腺瘤的CT表现,所有病例均经手术及病理证实.结果:结节性增生组与腺瘤组在患者性别、病变位置、病变的边界及同侧肾上腺形态方面存在显著统计学差异(P＜0.05).Logistic回归分析表明,病变边界清楚与否在两者鉴别中具有重要意义.结论:在肾上腺结节性增生与肾上腺腺瘤的鉴别诊断方面CT检查可提供重要参考.结合临床及实验室检查,将会对两者的鉴别提供更大的帮助.     

肾上腺皮质腺瘤和结节性增生的CT诊断（附35例分析）

本文报道经手术病理证实的肾上腺皮质腺瘤和结节性增生３５例，共发现４２个结节，讨论了ＣＴ检查方法、ＣＴ表现，鉴别诊断、误诊原因。提出了各类腺瘤及结节性增生的ＣＴ特征和腺瘤与结节性增生的鉴别诊断要点。认为ＣＴ扫描可以从病灶的密度，强化程度，大小有无包膜和对侧腺体有无萎缩或增大等征象来鉴别腺瘤和结节性增生。     

肾上腺占位病变的CT、MRI诊断(附71例报告)

目的探讨肾上腺占位病变的CT、MRI诊断价值,提高对肾上腺间质概念的认识. 资料与方法搜集1994年8月～2001年6月经手术和病理证实的肾上腺占位病变71例,46例行CT平扫,其中31例进行增强扫描;30例行MRI平扫,18例行增强扫描;共有5例行CT、MRI联合检查(平扫+增强). 结果 (1) 皮质占位36例(占50.7%),其中醛固酮腺瘤14例,皮质醇腺瘤11例,无功能腺瘤3例,皮质腺癌2例,皮质增生症6例;有1例伴性变态综合征.(2) 髓质占位29例(40.8%),其中嗜铬细胞瘤16例,成神经细胞瘤3例,节神经细胞瘤2例,转移瘤8例.(3)间质占位6例(8.5%),其中髓样脂肪瘤3例,囊肿2例,纤维脂肪瘤1例. 结论肾上腺占位病变多具有其特定的好发年龄、性别趋向及CT、MRI影像学特征,结合临床及实验室检查有助于提高占位病变诊断的准确性;但部分无功能腺瘤、转移瘤、间质肿瘤的定性诊断仍依赖于组织学检查.     

CT动态增强鉴别肾上腺乏脂肪腺瘤与肾上腺结节样增生的价值

目的探讨CT动态增强对鉴别肾上腺乏脂肪腺瘤与肾上腺结节样增生的价值。方法回顾性分析经手术病理证实的12例肾上腺乏脂肪腺瘤和27例肾上腺结节样增生患者的病例资料,统计两组病例各期增强CT值,利用公式灌注值P=CT静脉期-CT平扫期、廓清值C=CT静脉期-CT延迟期、绝对廓清灌注指数APC=(C/P)×100%及相对廓清灌注指数RAPC=(C/CT静脉期)×100%得到相关参数,并通过绘制受试者工作特征曲线,鉴别两者的最佳价值。结果肾上腺乏脂肪腺瘤直径较结节样增生更大;肾上腺乏脂肪腺瘤病灶各期CT值均明显高于结节样增生,且两者灌注值P、廓清值C、APC及RAPC有明显的统计学差异。年龄、性别、高血压、病灶位置、对侧肾上腺萎缩及动脉期CT值对鉴别两者无显著意义。结论CT动态增强扫描有助于鉴别肾上腺乏脂肪腺瘤和肾上腺结节样增生。     

Overview of adrenal imaging/adrenal CT

CT is the imaging procedure of choice for the detection of most suspected adrenal masses. But except for some patients with acute adrenal hemorrhage or fat-containing myelolipoma, the precise histologic nature of an adrenal mass is not apparent from the CT image. MIBG radionuclide scanning is useful in some patients with pheochromocytoma, whereas bilateral adrenal venous sampling for hormone assay is necessary for correct lateralization in some patients with a small aldosterone-producing adenoma. The potential value of MR imaging in the characterization of adrenal masses, especially to distinguish benign adrenal cortical adenomas from metastatic disease, is now under investigation. Currently percutaneous aspiration biopsy is still necessary to make this distinction in patients with an adrenal mass and a known extra-adrenal primary neoplasm.     

Overview of adrenal imaging/adrenal CT

CT is the imaging procedure of choice for the detection of most suspected adrenal masses. But except for some patients with acute adrenal hemorrhage or fat-containing myelolipoma, the precise histologic nature of an adrenal mass is not apparent from the CT image. MIBG radionuclide scanning is useful in some patients with pheochromocytoma, whereas bilateral adrenal venous sampling for hormone assay is necessary for correct lateralization in some patients with a small aldosterone-producing adenoma. The potential value of MR imaging in the characterization of adrenal masses, especially to distinguish benign adrenal cortical adenomas from metastatic disease, is now under investigation. Currently percutaneous aspiration biopsy is still necessary to make this distinction in patients with an adrenal mass and a known extraadrenal primary neoplasm.     

Efficacy of iodine-131 6beta-methyl-iodo-19-norcholesterol scintigraphy and computed tomography in patients with primary aldosteronism.

In order to define the role of scintigraphy in determining the aetiology of primary aldosteronism, 41 patients were examined by computed tomography (CT) scan and adrenal scintigraphy using iodine-131 6beta-methyl-iodo-19-norcholesterol with the dexamethasone suppression test. Hormonal and scintigraphic examinations were conducted while avoiding interference by medical treatment. The aetiological diagnosis was established by taking account of the clinical context, the endocrine profile, and CT scan and scintigraphic data, as well as possible hormone assays after catheterization of the adrenal veins (12 cases) and postoperative pathology data (14 cases). The aetiological diagnoses established were Conn's adenoma (insensitive to angiotensin II) in 12 cases, idiopathic hyperplasia in 11 and macronodular hyperplasia (with functional autonomy of the nodules) in 18. Unilateral and bilateral lesions were correctly distinguished by scintigraphy in 92% of cases as compared with only 58% using CT scan alone; this was because the CT scan appearance was normal in 3/12 cases of adenoma and because a single nodule was visible in 2/11 cases of idiopathic hyperplasia and in 12/18 cases of macronodular hyperplasia. It is concluded that scintigraphy using noriodocholesterol with the dexamethasone suppression test should be performed systematically in conjunction with hormonal tests and adrenal CT scan in all cases of primary aldosteronism, as part of a strategy aimed not only at detecting adenoma but also at determining whether the hyperfunctional lesions are bilateral.     

Scintigraphic studies in adrenal hypertension

Endocrine hypertension secondary to disorders of the adrenal glands is uncommon, but by no means rare. The importance of correct biochemical diagnosis and subsequent localization of the responsible lesion(s) lie in the fact that many of these syndromes occur in younger patients, may exhibit familial patterns of inheritance and are frequently amenable to surgical cure. The radiopharmaceuticals (131)1-6 beta-iodomethyl-19-norcholesterol (NP-59), a marker of adrenocortical cholesterol uptake, and (131)1- and (123)1-metaiodobenzylguanidine (MIBG), a norepinephrine (NE) analog and marker of energy-dependent NE storage vesicle accumulation, can be shown to accurately localize adrenal cortex and sympathoadrenal dysfunction, respectively. In Cushing's syndrome (CS) not only does the pattern of NP-59 uptake depict the adrenal dysfunction and its pathophysiologic basis, but the level of NP-59 accumulation reflects the degree of adrenocortical hyperfunction. Adrenocorticotrophin-independent CS is uniformly and accurately localized, especially in bilateral cortical nodular hyperplasia where even high resolution computed tomography (CT) may fail to depict the often subtle, asymmetric anatomic abnormalities. Dexamethasone suppression NP-59 adrenal scintigraphy has been shown to be highly sensitive and specific, and exceeds the efficacy of CT in the differentiation of adenoma and bilateral hyperplasia in primary aldosteronism. MIBG is useful as a sympathoadrenal imaging agent whose clinical utility has been demonstrated in the localization of pheochromocytoma, especially as a modality to screen the body for multiple and extraadrenal, recurrent, or metastatic lesions. Moreover, the extent of metastatic involvement from neuroblastoma can also be accurately depicted using MIBG. In this review we will examine the role of adrenal scintigraphy in the characterization of hypersecretory disorders of the adrenal cortex, medulla, and related conditions that produce hypertension as part of their symptom(s) complex. This approach, which is complementary to other anatomical modalities of imaging, can be used to advantage in the localization of functioning cortical and medulla adrenal diseases and other neoplasms of adrenergic origin.     

Preoperative diagnosis and localization of aldosteronomas by measurement of corticosteroids in adrenal venous blood.

Adrenal venous aldosterone/cortisol ratios were determined in 14 patients with primary aldosteronism. Of 12 patients diagnosed as having an adrenal adenoma, ten underwent surgery in which an adenoma was found. Bilateral adrenal hyperplasia was thought to have developed in two other patients. Measurement of adrenal vein cortisol and establishment of aldosterone/cortisol ratios were done to correct for catheter placement and dilute adrenal efflux. Determination of steroids after ACTH stimulation was helpful in distinguishing quiescent from suppressed adrenal in two patients and in confirming the diagnosis of the others.     

肾上腺疾病的影像诊断与鉴别诊断

目的：提高对肾上腺疾病的影像诊断水平,方法：收集1993年1月－1999年9月经MRI检查的151例疑继发性高血压病人中有完整住院资料的46例临床,MRI,CT,B超及实验室结果,按病因分为肾上腺腺病（11例）,嗜铬细胞瘤（11例）,皮质腺癌（7例）,肾上腺增生（17例）共4组,结果：（1）大小：腺瘤体积小（原发性醛固酮增多症小于3cm,柯兴综合征小于5cm),嗜铬细胞瘤大于3cm,增生0．6－3．5cm.（2）质地：腺瘤和增生质地均匀,呈等T1,等T2信号,CT值15－25H嗜铬细胞瘤和腺癌易出血坏死液化。（3）实验室检查,原醛通常高钠低钾血症,嗜铬细胞瘤和腺癌患者尿中VMA可呈阳性,（4）肾上腺增生大小,形态及生化结果多种多样。结论：影像检查有利于明上腺疾病的检出,结合临床及实验室检查可提高病变的定性诊断。     

Efficacy of iodine-131 6β-methyl-iodo-19-norcholesterol scintigraphy and computed tomography in patients with primary aldosteronism

In order to define the role of scintigraphy in determining the aetiology of primary aldosteronism, 41 patients were examined by computed tomography (CT) scan and adrenal scintigraphy using iodine-131 6β-methyl-iodo-19-norcholesterol with the dexamethasone suppression test. Hormonal and scintigraphic examinations were conducted while avoiding interference by medical treatment. The aetiological diagnosis was established by taking account of the clinical context, the endocrine profile, and CT scan and scintigraphic data, as well as possible hormone assays after catheterization of the adrenal veins (12 cases) and postoperative pathology data (14 cases). The aetiological diagnoses established were Conn’s adenoma (insensitive to angiotensin II) in 12 cases, idiopathic hyperplasia in 11 and macronodular hyperplasia (with functional autonomy of the nodules) in 18. Unilateral and bilateral lesions were correctly distinguished by scintigraphy in 92% of cases as compared with only 58% using CT scan alone; this was because the CT scan appearance was normal in 3/12 cases of adenoma and because a single nodule was visible in 2/11 cases of idiopathic hyperplasia and in 12/18 cases of macronodular hyperplasia. It is concluded that scintigraphy using noriodocholesterol with the dexamethasone suppression test should be performed systematically in conjunction with hormonal tests and adrenal CT scan in all cases of primary aldosteronism, as part of a strategy aimed not only at detecting adenoma but also at determining whether the hyperfunctional lesions are bilateral. Received 1 October 1998 and in revised form 3 June 1999     

Anomalous left adrenal venous drainage directly into the inferior vena cava

Primary hyperaldosteronism is a potential cause of hypertension. Unilateral adrenal adenoma and bilateral adrenal cortical hyperplasia are the most common causes of primary hyperaldosteronism. Adrenal venous sampling is employed as the gold standard test to differentiate between these two different causes when the results of other studies in the work-up protocol are non-diagnostic or ambiguous. Adrenal venous sampling can be a challenging procedure, especially in the presence of anomalous venous drainage patterns. Knowledge of normal adrenal venous anatomy, as well as possible variants, is therefore important to ensure a successful procedure. The authors describe an unusual variant of left adrenal venous drainage directly into the IVC.     

Usefulness of CT scan, MRI and radiocholesterol scintigraphy for adrenal imaging in Cushing's syndrome

The aim of this study was to evaluate the sensitivity and accuracy of computed tomography (CT) scanning, 75Se-selenomethyl-norcholesterol scintigraphy (SNS) and magnetic resonance imaging (MRI) in patients with Cushing's syndrome (CS) undergoing adrenalectomy. A series of 67 patients with CS due to benign adrenal disease was reviewed. There were 11 (16.4%) men and 56 (83.6%) women, with an overall median age of 44 years (range 19-69 years). Prior to surgery all patients underwent both CT and SNS, and 58 (86.6%) underwent adrenal MRI. Thirty-five (52.2%) of the patients (group A) had histologically confirmed unilateral adrenal involvement (33 patients with a solitary adrenocortical adenoma, and two with unilateral nodular cortical hyperplasia), while 32 (47.8%) of the patients (group B) had CS caused by bilateral adrenal involvement, including two patients with multinodular adrenal hyperplasia. The sensitivity, specificity and accuracy of adrenal imaging in group A were 97.1%, 100% and 98.5% for SNS, 94.3%, 68.7% (P<0.05, chi2 test) and 82.1% for CT scan, and 92.3%, 60.0% (P<0.05) and 64.3% (P<0.05) for MRI, respectively. In group B the sensitivity, specificity and accuracy were 100%, 97.2% and 98.5% for SNS, 64.5% (P<0.05), 97.2% and 82.1% for CT scan, and 60.0% (P<0.05), 92.3% and 35.7% (P<0.05) for MRI, respectively. In conclusion, SNS represents the most sensitive and specific adrenal imaging study and should be used in all patients with confirmed biochemical diagnosis of CS undergoing adrenalectomy. The sensitivity and specificity of CT scan and MRI are similar, but the latter shows a lower accuracy, especially in patients with bilateral adrenal involvement.     

Current developments in the radiologic diagnosis of the adrenal glands

Cross-sectional imaging techniques have dramatically improved the diagnosis of adrenal disease. In most patients with endocrine-active adrenal disease, CT is the only imaging test needed to establish the correct diagnosis. Adrenal venography with blood sampling may provide important additional information in patients with Conn adenoma. Magnetic resonance imaging and (IMBG) scintigraphy appear to be the best imaging tests for the localization of multiple or extra-adrenal pheochromocytomas. Inactive adrenal tumors detected incidentally are a problem as for as diagnosis is concerned, since inactive adrenal adenomas have to be differentiated from carcinomas and metastases. MRI is rarely helpful in these cases. For patients with a known primary tumor, the authors recommend CT-guided biopsy. In all other cases a follow-up study often reveals that the adrenal tumor detected is benign.