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The aim of this study was to evaluate the role of radionuclide imaging in the characterization of nonhypersecreting adrenal masses.A total of 54 patients (19 men, 35 women; mean age, 50 +/- 16 y) with nonhypersecreting unilateral adrenal tumors that had been originally detected on CT or MRI underwent adrenal scintigraphy using different radiotracers. None of the patients showed specific symptoms of adrenal hypersecretion. Screening tests for excess cortical and medullary products showed normal adrenal hormone levels. Radionuclide studies (n = 73) included (131)I-norcholesterol (n = 24), (131)I-metaiodobenzylguanidine (MIBG) (n = 23), and (18)F-FDG PET (n = 26) scans.Histology after surgery (n = 31) or adrenal biopsy (n = 23) was obtained. Adrenal lesions were represented by 19 adenomas, 4 cysts, 1 myelolipoma, 1 neurinoma, 2 ganglioneuromas, 5 pheochromocytomas, 4 pseudotumors, 6 carcinomas, 2 sarcomas, and 10 metastases (size range, 1.5- to 5-cm diameter; mean, 4.9 +/- 3.1 cm). For norcholesterol imaging, diagnostic sensitivity, specificity, and accuracy were 100%, 71%, and 92%, respectively; the positive predictive value (PPV) of the norcholesterol scan to characterize an adrenal mass as an adenoma was 89%, whereas the corresponding negative predictive value (NPV) to rule out this type of tumor was 100%. For MIBG imaging, diagnostic sensitivity, specificity, and accuracy were 100%, 94%, and 96%, respectively; the PPV of the MIBG scan to characterize an adrenal mass as a medullary chromaffin tissue tumor was 83%, whereas the corresponding NPV to rule out this type of tumor was 100%. For FDG PET, diagnostic sensitivity, specificity, and accuracy were 100%, 100%, and 100%, respectively; the PPV of FDG PET to characterize an adrenal mass as a malignant tumor was 100%, whereas the corresponding NPV to rule it out was 100%. Furthermore, in 7 patients with malignant adrenal tumors, FDG whole-body scanning revealed extra-adrenal tumor sites (n = 29), allowing an accurate diagnosis of the disease's stage using a single-imaging technique.In patients with nonhypersecreting adrenal masses, radionuclide adrenal imaging, using specific radiopharmaceuticals such as norcholesterol, MIBG, and FDG, may provide significant functional information for tissue characterization. Norcholesterol and MIBG scans are able to detect benign tumors such as adenoma and pheochromocytoma, respectively. Conversely, FDG PET allows for recognition of malignant adrenal lesions. Therefore, adrenal scintigraphy is recommended for tumor diagnosis and, hence, for appropriate treatment planning, particularly when CT or MRI findings are inconclusive for lesion characterization.

Two cases of haemorrhage from rupture of a splenic artery aneurysm into the pancreatic duct are reported. Both patients suffered from chronic pancreatitis; when haemorrhage appeared both patients experienced abdominal pain. In one patient the melaena was repetitive, in the other one--with a single episode of melaena - the endoscopy showed fresh blood near the papilla. In both patients ultrasonography and computerized tomography (CT) revealed a cystic mass in the pancreatic tail; CT scan also showed a clear contrast enhancement of these lesions after iodinated medium intravenous bolus. Coeliac arteriography confirmed the presence of two large saccular aneurysmal dilatation of the splenic artery. Both patients underwent a laparotomy: distal pancreatectomy with aneurysm resection and splenectomy were successfully performed.

The purpose of this study was to develop and test a method for the assessment of Magnetic Resonance (MR) scanner performance suitable for routine brain MR studies and for normalization of calculated relaxation times. We hypothesized that regular monitoring of machine performance changes could provide a helpful normalization tool for calculating tissue MR parameters, thus contributing to support their use for longitudinal and comparative studies of both normal and diseased tissues. The method is based on the acquisition of phantom images during routine brain studies with standard spin-echo sequences. MR phantom and brain tissue parameters were used to assess the influence of machine related changes on relaxation parameter estimates. Experimental results showed that scanner performance may affect relaxation rate estimates. Phantom and in vivo results indicate that the correction method yields a reduction in variability of estimated phantom R1 values up to 29% and of R1 for different brain structures up to 17%. These findings support the validity of using brain coil phantoms for routine system monitoring and correction of tissue relaxation rates.

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.

Magnetic Resonance Imaging (MRI) has been proposed as the diagnostic technique of choice to characterize adrenal tumors. However, the results of the current studies are controversial.Forty-nine patients with unilateral adrenal masses were submitted to MRI for lesion characterization on the basis of MR signal intensity. Cytology and/or histology demonstrated 14 pheochromocytomas (pheos), 11 adenomas, 3 cysts, 2 myelolipomas, 4 carcinomas, 3 metastases and 1 fibrosarcoma; a clinical diagnosis of adenoma was made in the remaining 11 patients. MR studies were performed using spin-echo (SE) sequences with T1 (TR/TE = 600/17 ms) and T2 (TR/TE = 2000/15-90 ms) weighting. T1-weighted images were also acquired after Gadolinium-DTPA (Gd-DTPA) administration. MR studies were integrated with in- and out-of-phase (TR/TE = 100/4-6 ms) chemical-shift (CS) sequences. MR signal intensity (SI) was analyzed qualitatively and quantitatively; MR results were correlated with tumor type and hormone secretion.The qualitative analysis of T2 images showed high signal intensity in the majority (80%) of adrenal lesions (14 pheos, 12 adenomas, 3 cysts, 2 myelolipomas and 8 malignancies). The quantitative analysis of post-Gd-DTPA T1 images permitted to distinguish adenomas, cysts and myelolipomas from pheos and malignancies. The qualitative analysis of post-Gd-DTPA T2 and T1 images permitted to distinguish pheos and cysts from adenomas and malignancies (p.05); however, pheos and cysts as well as adenomas and malignancies were not differentiated. MR SI was similar in secreting and nonsecreting adenomas from both a qualitative and a quantitative viewpoints. CS MRI permitted to distinguish adenomas (decreased signal intensity on out-phase relative to in-phase images) from other benign and malignant lesions (no signal change from out-phase to in-phase images).The qualitative analysis of MR SI on conventional T1 and T2 images does not permit to differentiate adrenal masses. The qualitative evaluation of T1 images after Gd-DTPA administration, the quantitative analysis and CS sequences are technical options improving lesion characterization.

OBJECTIVE: The aim of this study was to differentiate benign from malignant adrenal tumors using positron emission tomography (PET) with 18F-fluorodeoxyglucose (FDG) in patients with unilateral adrenal masses originally detected by CT or MR imaging. CONCLUSION: PET imaging with FDG can metabolically characterize adrenal masses. Abnormally increased FDG uptake in adrenal malignancies allows one to differentiate these abnormalities from benign lesions. Whole-body PET can also reveal extraadrenal tumor sites in patients with malignant tumors, using a single imaging technique for accurate disease staging.