Imaging characterization of non-hypersecreting adrenal masses. Comparison between MR and radionuclide techniques (original) (raw)
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The optimal imaging of adrenal tumours: a comparison of different methods
Endocrine Related Cancer, 2007
Computed tomography (CT; unenhanced, followed by contrast-enhanced examinations) is the cornerstone of imaging of adrenal tumours. Attenuation values of !10 Hounsfield units on an unenhanced CT are practically diagnostic for adenomas. When lesions cannot be characterised adequately with CT, magnetic resonance imaging (MRI) evaluation (with T1-and T2-weighted sequences and chemical shift and fat-suppression refinements) is sought. Functional nuclear medicine imaging is useful for adrenal lesions that are not adequately characterised with CT and MRI. Scintigraphy with [ 131 I]-6-iodomethyl norcholesterol (a labelled cholesterol analogue) can differentiate adrenal cortical adenomas from carcinomas. Phaeochromocytomas appear as areas of abnormal and/or increased uptake of [ 123 I]-and [ 131 I]-meta-iodobenzylguanidine (a labelled noradrenaline analogue). The specific and useful roles of adrenal imaging include the characterisation of tumours, assessment of true tumour size, differentiation of adenomas from carcinomas and metastases, and differentiation of hyperfunctioning from non-functioning lesions. Adrenal imaging complements and assists the clinical and hormonal evaluation of adrenal tumours.
Imaging of Adrenal Masses with Emphasis on Adrenocortical Tumors
Theranostics, 2012
Because of the more widespread and frequent use of cross-sectional techniques, mainly computed tomography (CT), an increasing number of adrenal tumors are detected as incidental findings ("incidentalomas"). These incidentaloma patients are much more frequent than those undergoing imaging because of symptoms related to adrenal disease. CT and magnetic resonance imaging (MRI) are in most patients sufficient for characterization and follow-up of the incidentaloma. In a minor portion of patients, biochemical screening reveals a functional tumor and further diagnostic work-up and therapy need to be performed according to the type of hormonal overproduction. In oncological patients, especially when the morphological imaging criteria indicate an adrenal metastasis, biopsy of the lesion should be considered after pheochromocytoma is ruled out biochemically. In the minority of patients in whom CT and MRI fail to characterize the tumor and when time is of essence, functional imaging mainly by positron emission tomography (PET) is available using various tracers. The most used PET tracer, [ 18 F]fluoro-deoxy-glucose ( 18 FDG), is able to differentiate benign from malignant adrenal tumors in many patients. 11 C-metomidate ( 11 C-MTO) is a more specialized PET tracer that binds to the 11-beta-hydroxylase enzyme in the adrenal cortex and thus makes it possible to differ adrenal tumors (benign adrenocortical adenoma and adrenocortical cancer) from those of non-adrenocortical origin.
Gland Surgery
The purpose of this pictorial essay is to review the imaging findings of adrenal lesions. Adrenal lesions could be divided into functioning or non-functioning masses, primary or metastatic, and benign or malignant. Imaging techniques have undergone significant advances in recent years. The most significant objective of adrenal imaging is represented by the detection and, when possible, characterization of adrenal lesions in order to direct patient management correctly. The detection and management of adrenal lesions is based on cross-sectional imaging obtained with non-contrast CT (tumour density), contrast-enhanced CT including delayed washout (either absolute percentage washout or relative percentage one) and finally with MR chemical shift analysis (loss of signal intensity between in-phase and out-of-phase images including both qualitative and quantitative estimates of signal loss). The small incidental adrenal nodules are benign, in most of cases; some tumors such as lipid-rich adenoma and myelolipoma have characteristic features that can be diagnosed accurately in CT. On contrary, if the presenting contrast-enhanced CT shows an adrenal mass with uncertain or malignant morphologic features, particularly in patients with a known history of malignancy, further evaluations should be considered. The most significative implications for radiologists are represented by how to assess risk of malignancy on imaging and what follow-up to indicate if an adrenal incidentaloma is not surgically removed.
A Multimodality Review of Adrenal Tumors
Current Problems in Diagnostic Radiology, 2018
Adrenal tumors are very commonly encountered in the practice of radiology. They may arise from the adrenal gland itself, either the cortex or the medulla, or they could be secondary lesions. They may be benign or malignant. The functioning adrenal tumors lead to hypersecretion of adrenal hormones leading to clinical syndromes. Computed tomography is the most common imaging modality used for the initial evaluation of adrenal tumors. Magnetic resonance imaging and functional scintigraphic techniques are frequently used for atypical presentations or further evaluation. We present a multimodality review of common and uncommon adrenal tumors. We highlight their characteristic and specific imaging features which help us in making a diagnosis and suggesting an appropriate follow up for further management. The spectrum of adrenal tumors is wide with varying appearances on different imaging modalities. Imaging techniques used for adrenal tumor imaging have their own strengths and weaknesses as it relates to the final diagnosis. It is important to be familiar with imaging characteristics of adrenal tumors for appropriate diagnosis and management. Differentiation of benign (leave alone) tumors from malignant (surgical) ones along with appropriate disposition of incidentalomas are some of the challenges facing the radiologist.
The Adrenal Mass: Correlation of Histopathology with Imaging
Annals of Surgical Oncology, 2010
Background. Computed tomography (CT) and magnetic resonance (MR) imaging can help diagnose benign adrenal adenomas, but prior studies rely on nonoperative follow-up as proof of a lesion's benign nature. We examined adrenalectomy tissues to determine if imaging characteristics correlate with histopathologic findings. Methods. We retrieved data for 196 consecutive adrenalectomies in 192 patients from 2000 to 2008. Imaging results were considered to signify benign adrenal adenoma if one or more of the following was present: Hounsfield units \10 on unenhanced CT, contrast-enhanced CT quantifying absolute contrast washout of [60% or relative contrast washout of [40%, or MR with chemical-shift imaging demonstrating loss of signal intensity on out-ofphase images. Results. The sensitivity and specificity of preoperative imaging in predicting benign adrenal adenoma were 57 and 94%, respectively. Histopathology confirmed that all 66 adrenal masses with imaging characteristics suggesting benign adenoma were indeed benign lesions and included 61 benign adrenal adenomas and 5 benign nonadenomatous lesions (3 myelolipomas, 1 composite myelolipoma/adenoma, and 1 ganglioliponeuroma). The specificity of imaging in predicting benignity was 100%. Malignant adrenal lesions were diagnosed in 17/130 (13%) masses: 8 metastases, 7 adrenal cortical carcinomas, 1 epithelioid angiosarcoma, and 1 ganglioneuroblastoma. The sensitivity of imaging in identifying malignancy was 100%. No malignancies were diagnosed during postoperative followup (mean 6 months, range 0.2-67 months). Conclusion. CT or MR characteristics predicted the presence of benign lesions with 100% specificity. Every adrenal malignancy had CT or MR results that were inconsistent with benign adenoma (100% sensitivity). To exclude malignancy, adrenal masses with non-benign imaging characteristics should be resected.
18F-FDG PET/CT in the evaluation of adrenal masses
Journal of nuclear medicine : official publication, Society of Nuclear Medicine, 2006
Our purpose was to evaluate the performance of (18)F-FDG PET/CT, using data from both the PET and the unenhanced CT portions of the study, in characterizing adrenal masses in oncology patients. One hundred seventy-five adrenal masses in 150 patients referred for (18)F-FDG PET/CT were assessed. Final diagnosis was based on histology (n = 6), imaging follow-up (n = 118) of 6-29 mo (mean, 14 mo), or morphologic imaging criteria (n = 51). Each adrenal mass was characterized by its size; its attenuation on CT, expressed by Hounsfield units (HU); and the intensity of (18)F-FDG uptake, expressed as standardized uptake value (SUV). Receiver operating characteristic curves were drawn to determine the optimal cutoff values of HU and SUV that would best discriminate between benign and malignant masses. When malignant lesions were compared with adenomas, PET data alone using an SUV cutoff of 3.1 yielded a sensitivity, specificity, positive predictive value, and negative predictive value of 98.5...
Imaging features of adrenal masses
Insights into Imaging
The widespread use of imaging examinations has increased the detection of incidental adrenal lesions, which are mostly benign and non-functioning adenomas. The differentiation of a benign from a malignant adrenal mass can be crucial especially in oncology patients since it would greatly affect treatment and prognosis. In this setting, imaging plays a key role in the detection and characterization of adrenal lesions, with several imaging tools which can be employed by radiologists. A thorough knowledge of the imaging features of adrenal masses is essential to better characterize these lesions, avoiding a misinterpretation of imaging findings, which frequently overlap between benign and malignant conditions, thus helping clinicians and surgeons in the management of patients. The purpose of this paper is to provide an overview of the main imaging features of adrenal masses and tumor-like conditions recalling the strengths and weaknesses of imaging modalities commonly used in adrenal imaging.
Clinical Endocrinology, 2008
Context Evidence regarding the accuracy of [123I] metaiodobenzylguanidine (MIBG) imaging for phaeochromocytoma localization is currently limited to small series.Objective We present the largest series of primary phaeochromocytomas in which the performance of [123I]MIBG has been evaluated and correlated with cross-sectional imaging.Design We identified 76 patients with both preoperative [123I]MIBG and cross-sectional imaging for confirmed primary phaeochromocytoma between 1995 and 2005 at our institution. This comprised 60 adrenal tumours in 55 patients and 33 extra-adrenal tumours in 23 patients (2 patients had both adrenal and extra-adrenal tumours). Phaeochromocytoma metastases were not evaluated.Main outcome measure(s) [123I]MIBG studies were independently reviewed and correlated with CT and MRI examinations, as well as tumour functional status, to identify features that may predict a false negative [123I]MIBG result.Results The overall sensitivity of [123I]MIBG was 75%. Tumour detection was lower for extra-adrenal (58%) vs. adrenal (85%) phaeochromocytomas (P = 0·005). For extra-adrenal tumours, [123I]MIBG demonstrated 8 of 14 carotid body, 2 of 2 intrathoracic, 8 of 14 retroperitoneal and 2 of 3 pelvic phaeochromocytomas. Overall, MRI and CT demonstrated 68 of 68 and 72 of 74 primary phaeochromocytomas, respectively. Tumour size correlated with [123I]MIBG uptake for adrenal (P = 0·009) but not extra-adrenal tumours. When tumours were adjusted for size, no other imaging feature or functional status correlated with [123I]MIBG negativity, although two large [123I]MIBG negative adrenal tumours contained large areas of necrosis or haemorrhage.Conclusions Extra-adrenal and small adrenal phaeochromocytomas are more likely to result in false negatives on [123I]MIBG. Tumoural necrosis or haemorrhage do not consistently relate to [123I]MIBG uptake, although adrenal phaeochromocytomas containing minimal solid tissue due to extensive necrosis may predict a negative [123I]MIBG result.