Magnetic resonance imaging is an important tool for the detection and characterization of adrenal tumors. The knowledge about the different presentations of primary and secondary adrenal tumors at magnetic resonance imaging and their correlation with histological data are essential for the establishment of a correct diagnosis. The present study reviews magnetic resonance imaging aspects which may narrow the differential diagnosis of adrenal tumors, emphasizing the histological correlation of the most frequent ones.

Keywords: Magnetic resonance imaging, Adrenal glands, Retroperitoneal neoplasms, Urogenital neoplasms, Imaging diagnosis

The authors present a review and iconographic study of patients with disseminated paracoccidioidomycosis, including the main radiographic findings seen in the central nervous system, adrenal glands, osteoarticular system, lymph nodes and digestive tract. Imaging diagnostic methods have allowed a more precise approach of these patients due to their high sensitivity in detecting lesions, even in asymptomatic patients. In most cases these abnormalities are unspecific, simulating either neoplasic or chronic infectious lesions, and sometimes difficult to distinguish from tuberculosis. Although these findings are nonspecific and only the mycologic and histologic fungus demonstration can confirm the diagnosis, they may suggest a presumptive one, when these imaging findings are considered in an appropriate clinical and epidemiological setting.

Keywords: Paracoccidioidomycosis, Central nervous system, Adrenals, Osteoarticular, Digestive, Lymph nodes

The authors review the main findings of primary adrenal lymphoma on abdominal and brain computed tomography (CT) scans and brain magnetic resonance imaging (MRI), and report a rare case of a 72-year-old male patient with deterioration in mental status progressing from recent memory loss to disorientation and ultimately dementia in a period of two months. The patient was investigated using imaging methods including brain (without intravenous administration of iodinated contrast media), chest and abdomen (pre and post intravenous administration of iodinated contrast media) CT scans and brain MRI (pre and post intravenous administration of gadolinium). Brain CT scan showed slightly hyperdense nodules adjacent to the lateral ventricles. No gross abnormalities were seen on the chest CT scan. CT of the abdomen showed solid nodules on both adrenals. Brain MRI showed diffuse nodular enhancement of the ependyma of the fourth ventricle, third ventricle, frontal and temporal horns, atria and body of the lateral ventricles. Definitive diagnosis was made by immunohistochemical study of the biopsed adrenal. After a comprehensive review of the literature the authors concluded that CT and MRI are essential methods for the detection and accurate evaluation of primary adrenal lymphomas, particularly when there is involvement of the central nervous system. MRI is more sensitive in the detection of extracerebral lesions in the epidural and subdural spaces, especially after intravenous administration of gadolinium.

Keywords: Adrenal lymphoma, Central nervous system metastases, Computed tomography, Magnetic resonance imaging

We evaluated the adrenals of individuals without tuberculosis (group 1 - G1) and with tuberculosis (group 2 - G2) using computed tomography. The antero-posterior length, the thickness, and the longitudinal length of the adrenals were compared in G1 and G2. The duration of the disease, the occurrence of morphologic abnormalities in G2, the distribution according to sex, age and skin color were also studied. There was difference in the antero-posterior length and thickness of right adrenal between G1 and G2. A higher prevalence of white skin male individuals was observed in G2. There was no association between duration of the disease and the occurrence of morphologic abnormalities in G2. A higher occurrence of adrenal enlargement was observed in G2. The main computed tomography findings in patients with tuberculosis were enlargement of the adrenal without calcification, enlargement of the adrenal with punctiform calcifications, and residual calcification of the adrenal.

Keywords: Adrenal, Tuberculosis, Computed tomography

We report a rare case of coexisting bilateral adrenal hemorrhage, right renal vein and inferior vena cava thrombosis in a neonate. Imaging studies played an important role in the diagnosis, management, and follow-up of this patient.

Keywords: Thrombosis, Adrenal glands, Hemorrhage, Neonate, Ultrasound, Computed tomography

With the steep increase in the use of cross-sectional imaging in recent years, the incidentally detected adrenal lesion, or "incidentaloma", has become an increasingly common diagnostic problem for the radiologist, and a need for an approach to classifying these lesions as benign, malignant or indeterminate with imaging has spurred an explosion of research. While most incidentalomas represent benign disease, typically an adenoma, the possibility of malignant involvement of the adrenal gland necessitates a reliance on imaging to inform management decisions. In this article, we review the literature on adrenal gland imaging, with particular emphasis on computed tomography, magnetic resonance imaging, and photon-emission tomography, and discuss how these findings relate to clinical practice. Emerging technologies, such as contrast-enhanced ultrasonography, dual-energy computed tomography, and magnetic resonance spectroscopic imaging will also be briefly addressed.

Keywords: Adrenal gland; Adenoma; Cancer; Diagnosis; Radiology.

OBJECTIVE: To evaluate a protocol for two-dimensional (2D) hydrogen proton (1H) magnetic resonance spectroscopy (MRS) (Siemens Medical Systems; Erlangen, Germany) in the detection of adrenal nodules and differentiation between benign and malignant masses (adenomas, pheochromocytomas, carcinomas and metastases). MATERIALS AND METHODS: A total of 118 patients (36 men; 82 women) (mean age: 57.3 ± 13.3 years) presenting with 138 adrenal nodules/masses were prospectively assessed. A multivoxel system was utilized with a 2D point-resolved spectroscopy/chemical shift imaging sequence. The following ratios were calculated: choline (Cho)/creatine (Cr), 4.0–4.3/Cr, lipid (Lip)/Cr, Cho/Lip and lactate (Lac)/Cr. RESULTS: 2D-1H-MRS was successful in 123 (89.13%) lesions. Sensitivity and specificity values observed for the ratios and cutoff points were the following: Cho/Cr > 1.2, 100% sensitivity, 98.2% specificity (differences between adenomas/pheochromocytomas and carcinomas/metastases); 4.0–4.3 ppm/Cr > 1.5, 92.3% sensitivity, 96.9% specificity (differences between carcinomas/pheochromocytomas and adenomas/metastases); Lac/Cr < –7.449, 90.9% sensitivity and 77.8% specificity (differences between pheochromocytomas and carcinomas/adenomas). CONCLUSION: Information provided by 2D-1H-MRS were effective and allowed for the differentiation between adrenal masses and nodules in most cases of lesions with > 1.0 cm in diameter.

Keywords: Adrenal gland; Magnetic resonance imaging; Spectroscopy.

OBJECTIVE: To assess the feasibility and reliability of apparent diffusion coefficient (ADC) measurements of normal adrenal glands. MATERIALS AND METHODS: This was a retrospective study involving 32 healthy subjects, divided into two groups: prepubertal (PreP, n = 12), aged from 2 months to 12.5 years (4 males; 8 females); and postpubertal (PostP, n = 20), aged from 11.9 to 61 years (5 males; 15 females). Diffusion-weighted magnetic resonance imaging (DW-MRI) sequences were acquired at a 1.5 T scanner using b values of 0, 20, 500, and 1000 s/mm². Two radiologists evaluated the images. ADC values were measured pixel-by-pixel on DW-MRI scans, and automatic co-registration with the ADC map was obtained. RESULTS: Mean ADC values for the right adrenal glands were 1.44 × 10^–3 mm²/s for the PreP group and 1.23 × 10^–3 mm²/s for the PostP group, whereas they were 1.58 × 10^–3 mm²/s and 1.32 × 10^–3 mm²/s, respectively, for the left glands. ADC values were higher in the PreP group than in the PostP group (p < 0.05). Agreement between readers was almost perfect (intraclass correlation coefficient, 0.84–0.94; p < 0.05). CONCLUSION: Our results demonstrate the feasibility and reliability of performing DW-MRI measurements of normal adrenal glands. They could also support the feasibility of ADC measurements of small structures.

Keywords: Adrenal glands; Diffusion magnetic resonance imaging; Magnetic resonance imaging.

OBJECTIVE: To describe a modified approach to the evaluation of adrenal nodules using a standard abdominal magnetic resonance imaging protocol. MATERIALS AND METHODS: Our sample comprised 149 subjects (collectively presenting with 132 adenomas and 40 nonadenomas). The adrenal signal intensity index was calculated. Lesions were grouped by pattern of enhancement (PE), according to the phase during which the wash-in peaked: arterial phase (type 1 PE); portal venous phase (type 2 PE); and interstitial phase (type 3 PE). The relative and absolute wash-out values were calculated. To test for mean differences between adenomas and nonadenomas, Student’s t-tests were used. Receiver operating characteristic curve analysis was also performed. RESULTS: The mean adrenal signal intensity index was significantly higher for the adenomas than for the nonadenomas (p < 0.0001). Chemical shift imaging showed a sensitivity and specificity of 94.4% and 100%, respectively, for differentiating adenomas from nonadenomas. Of the adenomas, 47.6%, 48.5%, and 3.9%, respectively, exhibited type 1, 2, and 3 PEs. For the mean wash-in proportions, significant differences were found among the enhancement patterns. The wash-out calculations revealed a trend toward better lesion differentiation for lesions exhibiting a type 1 PE, showing a sensitivity and specificity of 71.4% and 80.0%, respectively, when the absolute values were referenced, as well as for lesions exhibiting a type 2 PE, showing a sensitivity and specificity of 68.0% and 100%, respectively, when the relative values were referenced. The calculated probability of a lipid-poor lesion that exhibited a type 3 PE being a nonadenoma was > 99%. CONCLUSION: Subgrouping dynamic enhancement patterns yields high diagnostic accuracy in differentiating adenomas from nonadenomas.

Keywords: Adenoma; Adrenal gland neoplasms; Image enhancement; Contrast media; Magnetic resonance imaging.

OBJECTIVE: To evaluate the computed tomography characteristics of patients admitted with clinical suspicion of acute adrenal hemorrhage at three centers over a 3-year period and in whom that diagnosis was ultimately confirmed. MATERIALS AND METHODS: This was a retrospective analysis of computed tomography findings in patients with suspected acute adrenal hemorrhage. We included only those cases in which the diagnosis was confirmed. Patients with aortic rupture and retroperitoneal hemorrhage were excluded. The images were analyzed by an experienced radiologist and by two radiology residents. RESULTS: Six cases of unilateral adrenal hemorrhage (three on the left and three on the right) were analyzed. On computed tomography, each appeared as a rounded, oval mass altering the usual anatomy of the adrenal gland. The maximum diameter was 12.2 cm, and attenuation ranged from 45 to 70 HU. There was no appreciable contrast enhancement. No calcifications were observed. CONCLUSION: Adrenal hemorrhage, albeit rare, is potentially fatal. Early diagnosis is essential. Therefore, recognition of the possible presentations of these lesions by radiologists may help prevent hemorrhage from progressing to adrenal insufficiency and death.

Keywords: Adrenal glands; Hemorrhage; Tomography, X-ray computed.

OBJECTIVE: To investigate the advantages of using modified signal intensity measurements on chemical shift imaging alone or in conjunction with proton magnetic resonance spectroscopy in the differential diagnosis of adrenal adenomas. MATERIALS AND METHODS: This was a prospective study involving 97 patients with adrenal nodules or masses. The signal intensity index (SII) was calculated as [(signal intensity on the in-phase image − signal intensity on the out-of-phase image) / (signal intensity on the in-phase image)] × 100%. We determined the averages of the minimum, mean, and maximum signal intensity values measured on three consecutive images. When that was not possible (for smaller lesions), we used one or two images. We employed a region of interest that covered one half to two thirds of the mass. All indices were compared with metabolite ratios derived from spectroscopy: lactate/creatine; glutamine-glutamate/creatine; choline/creatine; choline/lipid; 4.0–4.3 ppm/Cr; and lipid/creatine. RESULTS: Of the 97 patients evaluated, 69 were diagnosed with adenomas and 28 were diagnosed with nonadenomas. All SII measurements and spectroscopy-derived metabolite ratios were significant to the differentiation between adenomas and nonadenomas, except for the lipid/creatine and choline/lipid ratios. In 37.8% of the cases, it was not possible to perform spectroscopy. When it was possible, the lactate/creatine ratio was found to have higher accuracy than did the SII. CONCLUSION: Determining the SII and metabolite ratios increased the accuracy of the differential diagnosis of adrenal adenomas.

Keywords: Adrenal glands; Adrenal gland neoplasms; Adenoma/diagnostic imaging; Magnetic resonance imaging/methods; Proton magnetic resonance spectroscopy/methods.

Os nervos cranianos representam extensões das estruturas funcionais do cérebro que cruzam a cabeça e o pescoço. Eles estão ligados a diferentes estruturas cranianas e se relacionam com diversas doenças. Uma compreensão profunda de sua complexa anatomia e aparência normal de imagem permite ao examinador identificar e caracterizar com mais precisão as anormalidades. A ressonância magnética com contraste é uma importante ferramenta para avaliar essas estruturas, especialmente as sequências tridimensionais de precessão livre de estado estacionário, que proporcionam alta resolução espacial e de partes moles, apesar da fina espessura dos nervos cranianos. Na maioria dos casos, os achados de imagem são inespecíficos, e uma anamnese completa, exame físico dirigido e testes laboratoriais são necessários para estreitar o diagnóstico diferencial. Este ensaio iconográfico ilustra e discute doenças congênitas, traumáticas e vasculares dos nervos cranianos, mostrando imagens em uma abordagem fisiopatológica.

Keywords: Neuroimagem/métodos; Radiologia/métodos; Ressonância magnética/métodos; Nervos cranianos/diagnóstico por imagem.

OBJECTIVE: To estimate the frequency of lipid-poor adenomas (LPAs) in magnetic resonance imaging (MRI) examinations. MATERIALS AND METHODS: We retrospectively investigated adrenal lesions on MRI examinations performed in a total of 2,014 patients between January 2016 and December 2017. After exclusions, the sample comprised 69 patients with 74 proven adenomas. Two readers (reader 1 and reader 2) evaluated lesion size, laterality, homogeneity, signal drop on out-of-phase (OP) images, and the signal intensity index (SII). An LPA was defined as a lesion with no signal drop on OP images and an SII < 16.5%. For 68 lesions, computed tomography (CT) scans (obtained within one year of the MRI) were also reviewed. RESULTS: Of the 69 patients evaluated, 42 (60.8%) were women and 27 (39.2%) were men. The mean age was 59.2 ± 14.1 years. Among the 74 confirmed adrenal adenomas evaluated, the mean lesion size was 18.5 ± 7.7 mm (range, 7.0–56.0 mm) for reader 1 and 21.0 ± 8.3 mm (range, 7.0–55.0 mm) for reader 2 (p = 0.055). On the basis of the signal drop in OP MRI sequences, both readers identified five (6.8%) of the 74 lesions as being LPAs. When determined on the basis of the SII, that frequency was three (4.0%) for reader 1 and four (5.4%) for reader 2. On CT, 21 (30.8%) of the 68 lesions evaluated were classified as LPAs. CONCLUSION: The prevalence of LPA was significantly lower on MRI than on CT. That prevalence tends to be even lower when the definition of LPA relies on a quantitative analysis rather than on a qualitative (visual) analysis.

Keywords: Adenoma/diagnostic imaging; Adrenal gland neoplasms/diagnostic imaging; Incidental findings; Magnetic resonance imaging; Tomography, X-ray computed.