~(99)Tc~m-HTOC和~(131)Ⅰ-MIBG显像诊断嗜铬细胞瘤的比较

目的比较和评价~(99)Tc~m-奥曲肽(HTOC)和~(131)Ⅱ-间碘苄胍(MIBG)显像诊断嗜铬细胞瘤的临床价值。方法 28例临床疑嗜铬细胞瘤患者先后进行~(99)Tc~m-HTOC 和~(131)Ⅰ-MIBG 全身显像,如全身显像发现异位病灶则加做同机 CT 融合检查。结果 28例中最终证实为嗜铬细胞瘤者19例,18例经手术或活组织病理检查证实,1例经生化和其他影像学检查证实。28例患者中9例~(99)Tc~m-HTOC 和~(131)Ⅰ-MIBG 显像均阳性,病灶位于心脏1例、腹主动脉旁3例、肾上腺3例,恶性多发病灶2例;恶性多发患者~(99)Tc~m-HTOC 显像发现的病灶多于~(131)Ⅰ-MIBG。~(99)Tc~m-HTOC 显像阳性而~(131)I-MIBG 显像阴性患者共5例,病灶位于心脏3例,恶性多发病灶2例。~(99)Tc~m-HTOC 显像阴性而~(131)Ⅰ-MIBG 显像阳性4例,病灶均位于肾上腺。两种显像均阴性10例,1例为嗜铬细胞瘤伴囊性变,其他9例均除外嗜铬细胞瘤。~(99)Tc~m-HTOC 和~(131)Ⅰ-MIBG 显像的灵敏度、特异性、准确性分别为73.7%、100%、82.1%和68.4%、100%、78.5%。~(99)Tc~m-HTOC 显像对异位于心脏的嗜铬细胞瘤和恶性多发病灶的诊断明显优于~(131)I-MIBG,但对肾上腺来源的嗜铬细胞瘤的检出不如~(131)Ⅰ-MIBG。结论 ~(131)Ⅰ-MIBG 显像仍是诊断嗜铬细胞瘤的首选检查,但结果阴性时需进行~(99)Tc~m-HTOC 显像.     

Computed tomography and 131I-MIBG scintigraphy in the diagnosis of pheochromocytoma

In order to evaluate the usefulness of computed tomography (CT) and 131I meta-iodobenzylguanidine (131I-MIBG) scintigraphy for the localization of pheochromocytoma, a prospective study was undertaken in 23 patients with possible pheochromocytoma. Seventeen tumors were identified in 13 patients. Two tumors were extra-adrenal. CT was superior for locating tumors in the adrenal glands while 131I-MIBG scintigraphy was more useful in the detection of extra-adrenal pheochromocytoma. Together with adrenal and extra-adrenal pheochromocytoma, the sensitivity for locating the tumor was calculated as 82 per cent (14/17) for CT and 76 per cent (13/17) for 131I-MIBG scintigraphy, respectively. One adrenal tumor (1 cm in size) only was missed by both methods. No false positive CT scans of 131I-MIBG scintigraphy were obtained in the remaining 10 patients who had possible pheochromocytoma but were excluded. These results indicated that CT and 131I-MIBG scintigraphy were both useful tools for detecting pheochromocytoma.     

The assessment of clinical usefulness of 131I-MIBG scintigraphy for localization of tumors of sympathetic and adrenomedullary origin--a report of multicenter phase III clinical trials]

A phase III clinical study of 131I-metaiodobenzylguanidine (131I-MIBG) was performed in 66 patients with tumors of sympathetic and adrenomedullary origin, including 32 patients with suspected pheochromocytoma, 25 with suspected neuroblastoma, 7 pre- or postoperative medullary carcinoma of the thyroid and each with carcinoid and suspected Sipple's syndrome. A total of 150 sites which were confirmed for presence (72 sites) or absence (78 sites) of tumors were examined on 131I-MIBG scintigrams. True positive ratio of the scintigraphy was 84.7% (61/72) and true negative ratio was 94.9% (74/78). Positive scintigraphy was obtained in 86.5% (32/37) of pheochromocytoma, 78.6% (22/28) of neuroblastoma and 100% (6/6) of medullary carcinoma of the thyroid. Accumulation of 131I-MIBG was seen in 16.8% of normal adrenal glands. Neither adverse reactions nor abnormal laboratory findings were noted in relation to 131I-MIBG injections. Our study indicates that 131I-MIBG is a safe and clinically useful radiotracers for the visualization and localization of tumors of sympathetic and adrenomedullary origin.     

131I-meta-iodobenzylguanidine scintigraphy in patients with a suspected pheochromocytoma. A comparison with CT and biohumoral parameters]

The results of 131I metaiodobenzylguanidine (MIBG) and Computed Tomography (CT) scans in a group of patients with clinically suspected pheochromocytoma were evaluated and compared with biohumoral parameters. We studied 24 consecutive patients (7 M and 17 F; age range 20-66 years). 131I-MIBG scintigraphy and CT were in agreement in 19 patients (79%): of them 7 cases were true positive, and 12 were true negative. Disagreement between the two imaging techniques was observed in 5 patients (21%). In this group, one patient, with positive CT scan, had false negative MIBG study, while 4 patients with negative MIBG scan, had false positive CT. MIBG showed significantly higher (p less than 0.05) specificity (100%), positive predictive value (100%), and accuracy (96%) than CT (75%, 67%, and 83%, respectively). 131I-MIBG scintigraphy is an accurate, noninvasive technique for localizing pheochromocytoma and providing direct tissue characterization, while CT provides more accurate spatial information. In conclusion, CT and MIBG studies are complementary in the evaluation of patients with suspected pheochromocytoma.     

Adrenal masses in oncologic patients: functional and morphologic evaluation

The role of adrenocortical scintigraphy in the evaluation of unilateral adrenal masses detected with computed tomography (CT) in 28 oncologic patients with normal adrenal function was studied prospectively with the use of NP-59 (iodine-131-6-iodomethyl-19-norcholesterol). The diagnosis was proved by means of percutaneous fine-needle aspiration cytologic examination in 20 patients, surgical biopsy in one, and clinical and CT follow-up in seven. In 14 of the 28 patients, there was increased uptake of the NP-59 on the side of the adrenal mass detected at CT (concordant uptake). Thirteen of the 14 masses with concordant uptake were greater than 2 cm in diameter, and one was 1.5 cm; all were found to be adenomas. In 11 of 28 patients there was decreased uptake on the side of the mass detected at CT (discordant uptake). None of these 11 masses were adenomas; nine were metastases and two were adrenal cysts. Uptake was indeterminate (symmetric) in three patients, two of whom had adrenal adenomas and one an adrenal metastasis; each mass with indeterminate uptake was less than 2 cm in diameter.     

CT of pheochromocytoma

The computed tomographic (CT) findings in 10 patients with pheochromocytoma are presented. Three of 10 patients had multiple endocrine adenomatosis, all with bilateral adrenal masses. One other patient had bilateral adrenal masses, four had right, and one had left sided adrenal masses. One tumor was extraadrenal. CT, when used as the initial imaging study, correctly identified nine of nine pheochromocytomas in six patients. In another four patients, recurrent or metastatic disease was identified. CT findings of use in diagnosis were mass lesions, some with areas of decreased attenuation indicating hemorrhage, and metastases identified in liver, mediastinum, lung, and spine. CT differentiation of benign from malignant lesions is facilitated by demonstration of local invasion or metastasis. CT is recommended as the initial radiographic procedure in the evaluation of patients with clinical or biochemical suspicion of pheochromocytoma, and for follow-up examination in patients with evidence of recurrent disease.     

Complementary roles of CT and 131I-MIBG scintigraphy in diagnosing pheochromocytoma

Recently 131I-MIBG (metaiodobenzylguanidine), an adrenergic tissue-localizing radiopharmaceutical, has been used for diagnosis of pheochromocytoma. In a retrospective study of 32 patients with pathologically proved primary, metastatic, or recurrent pheochromocytoma, the roles of 131I-MIBG scintigraphy and computed tomography (CT) in pheochromocytoma detection were compared. The two methods were equally accurate in the identification of primary and recurrent pheochromocytoma. 131I-MIBG scanning was more accurate as the initial examination in patients with extraadrenal tumors. In patients with metastatic disease, scintigraphy was preferable to CT because of its nontomographic nature, which permitted imaging of the entire body. Although a positive MIBG scan is diagnostic of pheochromocytoma, CT of extraadrenal tumors (particularly in the chest) has been very useful in planning appropriate surgical intervention. Furthermore, the roles of 131I-MIBG scintigraphy and CT in the detection of pheochromocytoma are complementary because each method has certain limitations.     

Diagnostic accuracy of radionuclide imaging using 131I nor-cholesterol or meta-iodobenzylguanidine in patients with hypersecreting or non-hypersecreting adrenal tumours

The aim of this retrospective study was to evaluate the diagnostic accuracy of nor-cholesterol and meta-iodobenzylguanidine radionuclide imaging in two separate groups of patients with adrenal tumours to characterize lesions as adenoma or pheochromocytoma. We studied 75 patients (22 male and 53 female, mean age 47 +/- 15 years) with hypersecreting (n = 32) or non-hypersecreting (n = 43) unilateral adrenal tumours detected by computerized tomography or magnetic resonance scans. 131I nor-cholesterol adrenal scintigraphy was performed in 41 patients. Meta-[131I]iodobenzylguanidine (131I-MIBG) imaging was acquired in the other 34 patients. Pathology examinations (n = 58) or computerized tomography follow-up studies (n = 17) were obtained. Adrenal lesions were represented by 44 adenomas, four cysts, one myelolipoma, one pseudotumour, one ganglioneuroma, 16 pheochromocytomas, three carcinomas, four metastases and one sarcoma. Radionuclide studies were qualitatively evaluated and the corresponding results were classified as true positive, true negative, false positive and false negative. Diagnostic sensitivity, specificity and accuracy as well as positive and negative predictive values were calculated. The diagnostic values of nor-cholesterol scintigraphy in identifying adrenal adenomas were sensitivity 100%, specificity 71%, accuracy 95%, positive predictive value 94% and negative predictive value 100%; of note, two false positive cases were observed represented by a pheochromocytoma and a myelolipoma. The diagnostic values of MIBG scintigraphy in recognizing pheochromocytoma were sensitivity 100%, specificity 95%, accuracy 97%, positive predictive value 94% and negative predictive value 100%; only one false positive case occurred consisting of a carcinoma. It is concluded that, in the large majority of cases, adrenal scintigraphy using nor-cholesterol or MIBG is able to characterize specific lesions such as adenoma and pheochromocytoma, respectively. These findings show relevant clinical impact, particularly in patients with non-hypersecreting adrenal lasions. Radiotracer selection depends on clinical patient history and department availability; since benign adenomas are the most common cause of non-hypersecreting tumours, nor-cholesterol should be the first choice followed by MIBG if nor-cholesterol shows normal images. However, rare as well as unusual findings may be observed; nor-cholesterol uptake may occasionally be also found in non-adenoma tumours such as myelolipoma and pheochromocytoma. Similarly, MIBG accumulation may occur not only in lesions arising from medullary chromaffin tissue, but also rarely in cortical adrenal carcinoma.     

The role of adrenocortical scintigraphy in the evaluation of unilateral incidentally discovered adrenal and juxtaadrenal masses

We reviewed the findings of adrenocortical scintigraphy with¹³¹I-6-beta-iodomethyl-19-norcholesterol (NCL-6-¹³¹I) of 39 patients to clarify its role in the evaluation of unilateral adrenal or juxtaadrenal masses incidentally discovered by CT, ultrasonography or plain radiography. Twenty-seven benign adrenal masses showed various scintigraphic findings (hot nodule: 12 silent adenomas, warm nodule: one solid mass, normal appearance: one cyst and 2 solid masses, diffuse decrease: each one; solid mass, myelolipoma, ganglioneuroma and calcified adrenal and partial or complete defect: each one; solid mass, myelolipoma and ganglioneuroma and 2 cysts and 2 pheochromocytomas); while a partial or complete defect was shown in a nonfunctioning carcinoma and 3 metastases and a complete defect or inhomogeneous uptake without opposite adrenal visualization was shown in 2 patients with cortisol-producing carcinoma. Therefore a hot nodule and an inhomogenous uptake or complete defect with nonvisualization of the opposite adrenal are specific to a benign tumor and a cortisol-producing carcinoma, respectively. The impaired tumor uptake of NCL-6-¹³¹I is a nonspecific finding. The scintigraphic findings of juxtaadrenal masses were normal in 4 and deviated adrenals in 2. Thus adrenocortical scintigraphy can identify silent adenomas and cortisol-producing carcinomas among the adrenal masses and may help to differentiate juxtaadrenal from adrenal masses.     

Diagnostic accuracy of 68Ga-DOTANOC PET/CT imaging in pheochromocytoma

Purpose

The purpose of the present study was to evaluate the diagnostic accuracy of ⁶⁸Ga-DOTANOC positron emission tomography (PET)/CT in patients with suspicion of pheochromocytoma.

Methods

Data of 62 patients [age 34.3?±?16.1 years, 14 with multiple endocrine neoplasia type 2 (MEN2)] with clinical/biochemical suspicion of pheochromocytoma and suspicious adrenal lesion on contrast CT (n?=?70), who had undergone ⁶⁸Ga-DOTANOC PET/CT, were retrospectively analyzed. PET/CT images were analyzed visually as well as semiquantitatively, with measurement of maximum standardized uptake value (SUV_max), SUV_mean, SUV_max/SUV_liver, and SUV_mean/SUV_liver. Results of PET/CT were compared with ¹³¹I-metaiodobenzylguanidine (MIBG) imaging, which was available in 40 patients (45 lesions). Histopathology and/or imaging/clinical/biochemical follow-up (minimum 6 months) was used as reference standard.

Results

The sensitivity, specificity, and accuracy of ⁶⁸Ga-DOTANOC PET/CT was 90.4, 85, and 88.7 %, respectively, on patient-based analysis and 92, 85, and 90 %, respectively, on lesion-based analysis. ⁶⁸Ga-DOTANOC PET/CT showed 100 % accuracy in patients with MEN2 syndrome and malignant pheochromocytoma. On direct comparison, lesion-based accuracy of ⁶⁸Ga-DOTANOC PET/CT for pheochromocytoma was significantly higher than ¹³¹I-MIBG imaging (91.1 vs 66.6 %, p?=?0.035). SUV_max was higher for pheochromocytomas than other adrenal lesions (p?=?0.005), MEN2-associated vs sporadic pheochromocytoma (p?=?0.012), but no difference was seen between benign vs malignant pheochromocytoma (p?=?0.269).

Conclusion

⁶⁸Ga-DOTANOC PET/CT shows high diagnostic accuracy in patients with suspicion of pheochromocytoma and is superior to ¹³¹I-MIBG imaging for this purpose. Best results of ⁶⁸Ga-DOTANOC PET/CT are seen in patients with MEN2-associated and malignant pheochromocytoma.     

18F-FDG PET/CT显像SUVmax与嗜铬细胞瘤恶性程度的相关性探讨

目的 分析嗜铬细胞瘤18 F-FDG PET/CT显像SUVmax与血浆游离甲氧基肾上腺素(MN)、甲氧基去甲肾上腺素(NMN)及131I-间位碘代苄胍(MIBG) SPECT显像间的关系,探讨18F-FDG PET/CT在诊断嗜铬细胞瘤和预测嗜铬细胞瘤恶性程度中的价值.方法 采用回顾性研究方法,收集经18F-FDG PET/CT检查且手术病理证实为嗜铬细胞瘤的患者19例,按其生物学行为分为良性组(n=11)与恶性组(n=8),查询PET/CT检查前后血MN、NMN及131 I-MIBG SPECT的检查结果,利用SPSS 17.0软件行两独立样本t检验,并绘制ROC曲线,探讨嗜铬细胞瘤SUVmax的特点,比较分析各检查之间的关系.结果 (1)11例良性嗜铬细胞瘤(BPCC)与8例恶性嗜铬细胞瘤(MPCC)PET/CT显像均为阳性;MPCC的SUVmax(19.40±7.39)明显大于BPCC的SUVmax (7.44±4.47),t=-4.40,P＜0.01;用约登指数法,确定SUVmax=8.85为判断嗜铬细胞瘤良恶性的分界值,其灵敏度、特异性和准确性分别为8/8、81.8％(9/11)、89.5％ (17/19);异位嗜铬细胞瘤SUVmax为19.75±8.64,明显高于肾上腺嗜铬细胞瘤SUVmax (9.12±5.83),t=-3.18,P＜0.05;初发与复发的嗜铬细胞瘤SUVmax间差异无统计学意义(t=-1.68,P＞0.05).(2)MN阴性病例SUVmax( 13.57±8.61)明显高于MN阳性病例SUVmax (6.63±2.42),t =2.70,P＜0.05;NMN阴性与阳性的病例SUVmax间差异无统计学意义(t=-0.93,P＞0.05).(3)7例同期行18F-FDG PET/CT与131I-MIBG SPECT患者中,3例BPCC,其中2例MIBG显像阳性,4例MPCC MIBG显像均为阴性;7例PET/CT显像均为阳性.结论 对于血MN与MIBG检查为阴性、但临床疑为嗜铬细胞瘤患者,FDG PET/CT可作为辅助诊断手段,减少漏诊率.     

Pheochromocytoma in multiple endocrine neoplasia type 2A: positive 123I MIBG with negative CT and equivocal 131I MIBG imaging

An 123I metaiodobenzylguanidine (MIBG) planar image showed abnormal uptake in the left adrenal gland and thyroid in a 24-year-old woman with multiple endocrine neoplasia type 2A. 131I MIBG showed abnormal uptake in the thyroid but not in the adrenal gland. Abdominal CT with 2-mm thin slices demonstrated a normal adrenal gland. Postoperative pathologic findings were consistent with medullary carcinoma in both thyroid lobes and a small 1-mm pheochromocytoma in the left adrenal gland. 123I MIBG could clearly show the small pheochromocytoma, which was negative in thin-slice CT and equivocal in 131I MIBG.     

Results of scintigraphic studies with 131I-meta-benzylguanidine in space-occupying lesions of neuroectodermal origin

Between 1982 and 1984, 48 studies with 131I-meta-benzylguanidine were carried out in Erlangen in patients with suspected pheochromocytoma or neuroblastoma. Scintigraphy with MIBG was found to be highly specific. False positive findings can be avoided if with weak uptakes an exact correlation with the results of morphological studies such as CT or sonography is sought and if follow-up observations ensure that they are not caused by activity residues in the biliary, intestinal or urinary pathways. False negative findings are made in 5-10% of the investigations in pheochromocytoma and in 41% of those in neuroblastoma patients. In pheochromocytoma the uptake rates are generally low (1-2%), whereas in neuroblastoma they may reach 10% and more.     

A new medico-nuclear outlook for the diagnosis and treatment of pheochromocytomas: 131I-meta-iodobenzylguanidine (131I-MIBG). Comments on results obtained

The diagnostic and therapeutic potential of 131I-MIBG, the new imaging agent with structural similarity to norepinephrine, was evaluated in 23 patients with a suspect pheochromocytoma. Seven out of 8 benign pheochromocytomas (2 ectopic) were correctly localized with 131I-MIBG scintigraphy (1 false negative). In 2 catecholamine-secreting malignant pheochromocytomas both the primary tumor and the metastases (1 case) were demonstrated. One uncommon case of dopamine-secreting malignant pheochromocytoma, as expected, was not shown. In the remaining 12 cases, found to be "normal" after completing the work-up, distribution of the radiopharmaceutical was evaluated using a semiquantitative grading system. 131I-MIBG scintigraphy proved to be a non invasive and accurate (95%) diagnostic modality, specific for neuroadrenergic tumors. The treatment with 131I-MIBG was also carried out in 2 malignant pheochromocytomas with encouraging results.     

Chromogranin A assay and (131)I-MIBG scintigraphy for diagnosis and follow-up of pheochromocytoma.

We assessed the performance of a new serum chromogranin A (CgA) assay in combination with the results of (131)I-metaiodobenzylguanidine (MIBG) scintigraphy for diagnosis and follow-up in 89 patients with clinical findings suggestive of pheochromocytoma. METHODS: The study population consisted of 41 patients with proven pheochromocytoma and 48 patients with refuted pheochromocytoma. Eighty-seven scintigraphy examinations were performed, 52 in patients with proven pheochromocytoma (39 before surgery and 13 after surgery) and 35 in patients with refuted pheochromocytoma. RESULTS: The sensitivity of the CgA level was 90.2%, and the specificity was 99.0% and 92.3% in the control and refuted pheochromocytoma groups, respectively. A significant relationship was seen between serum levels of CgA and tumor mass (r = 0.70; P < 10(-5)). The postoperative CgA level was an early and accurate predictor of curative surgery or relapse. The concordance between CgA levels and scintigraphic data was 90.8%. CONCLUSION: Serum CgA level is an effective marker of pheochromocytoma. Increased levels strongly correlate with tumor mass; therefore, small tumors may go undetected. The concordance between CgA level and the results of (131)I-MIBG scintigraphy is high. A CgA level in the reference range is highly predictive of normal scintigraphy findings.     

A comparison of scintigraphy with radioiodinated MIBG and CT in localizing pheochromocytomas

In order to define the diagnostic roles of MIBG imaging and CT in the detection of pheochromocytomas (pheos), the results obtained in 45 patients suspected of bearing pheo and studied with both modalities were analyzed and compared. Scintigraphy was correctly negative in 22/23 cases, correctly positive in 11/12 adrenal and 5/5 extra-adrenal pheos, and in 4/5 malignant pheos (metastases present in 2 cases were also identified). CT was correctly negative in 20/23 cases (a mass other than a pheo was detected in 3 patients); correctly positive in 12/12 adrenal and 4/5 extra-adrenal pheos and in 5/5 malignant pheos. Sensitivity, specificity and accuracy of scintigraphy and CT were 91% and 95.4%, 95.6% and 87%, 93.3% and 91.1% respectively (differences were not statistically significant). The overall data emphasize the complementary role of 123/131I-MIBG imaging and CT in the location of pheochromocytomas. A flow-chart essentially grounded on the combined use of both these diagnostic modalities is proposed which includes 123/131I-MIBG scintigraphy as a first choice examination.     

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.     

SPECT／CT图像融合显像定位诊断异位或转移性嗜铬细胞瘤的应用价值

目的:为临床手术治疗异位或恶性嗜铬细胞瘤转移灶提供定性和准确解剖定位.材料和方法:对临床怀疑嗜铬细胞瘤的131例患者行131I-MIBG全身显像,发现其中10例肾上腺以外部位有异常放射性浓聚区,对该部位进行SPECT/CT同机图像融合断层显像,分别获得SPECT发射断层图像、CT透射断层图像及准确定位的融合图像.结果:对131I-MIBG全身显像发现异位及恶性嗜铬细胞瘤转移灶,不能明确解剖定位的病例,经SPECT/CT图像融合断层显像后,均获得明确的准确解剖定位.结论:SPECT/CT图像融合显像能够定性并准确定位异位或转移性嗜铬细胞瘤,为临床手术治疗提供重要的依据.     

Scintigraphy of incidentally discovered bilateral adrenal masses

The purpose of this study was to determine the patterns of iodine-131 6-iodomethylnorcholesterol (NP-59) imaging and the correlation with computed tomography (CT)-guided adrenal biopsy and follow-up in patients with bilateral adrenal masses. To this end we investigated a consecutive sample of 29 euadrenal patients with bilateral adrenal masses discovered on CT for reasons other than suspected adrenal disease. Adrenal scintigraphy was performed using 1 mCi of NP-59 injected intravenously, with gamma camera imaging 5–7 days later. In 13 of the 29 patients bilateral adrenal masses were the result of metastatic involvement from lung carcinoma (5), lymphoma (3), adrenocarcinoma of the colon (3), squamous cell carcinoma of the larynx (1), and anaplastic carcinoma of unknown primary (1). Among these cases the NP-59 scan demonstrated either bilaterally absent tracer accumulation (in eight, all with bilateral metastases proven by CT guided biopsy or progression on follow-up CT) or marked asymmetry of adrenocortical NP-59 uptake (in five). Biopsy of the adrenal demonstrating the least NP-59 uptake documented malignant involvement of that gland in five of five patients. In two patients an adenoma was found simultaneously in one adrenal with a contralateral malignant adrenal mass. In each of these cases, the adenoma demonstrated the greatest NP-59 uptake. In 16 patients diagnosis of adenoma was made on the basis of (a) CT guided adrenal biopsy of the gland with the greatest NP-59 uptake of the pair (n=4), or (b) adrenalectomy (n=2), or (c) absence of change in the size of the adrenal mass on follow-up CT scanning performed 6 months to 3 years later (n=10). It is concluded that differential in vivo functional information provided by NP-59 scintigraphy complements that derived from anatomic imaging and can be used in patients with bilateral adrenal masses to select which gland would be the best choice for further diagnostic invasive evaluation (e.g., adrenal biopsy) or may suggest the presence of bilateral adrenal metastases in patients with incidentally discovered, bilateral adrenal masses.     

Radiopharmacokinetics and radiation absorbed dose calculations from 131I-meta-iodobenzylguanidine (131I-MIBG)

In connection with clinical 131I-MIBG studies of patients with suspected pheochromocytoma and adrenomedullary hyperplasia quantitative biokinetic data have been collected in order to improve the present estimations of absorbed dose to various organs and tissues. Whole-body profiles as a function of time were measured with a whole-body counter. The retention in the total body and in the thyroid gland could be derived from the measured whole-body profiles by summing up the corresponding values. The retention of 131I-MIBG could not be exactly measured for further organs from the whole-body profiles in man. For this reason animal studies were performed with mice. The biokinetic animal data were transferred to man in form of the cumulative activity for the various organs. The mean absorbed dose for selected organs per injected activity unit was calculated using the concept of absorbed fractions (MIRD method) taking into account the radioactivity within the remaining body. Except for both the adrenal medulla and the thyroid gland the absorbed doses for all the other selected organs are in a range from 0.108 mGy MBq-1 for the testes to 0.176 mGy MBq-1 for the lungs. The absorbed dose to the thyroid gland amounts to the considerable value of 5.69 mGy MBq-1 although the thyroid gland was blocked. The greatest absorbed dose was estimated for the normal adrenal medulla with 18.67 mGy MBq-1.