Distinguishing benign from malignant euadrenal masses.

STUDY OBJECTIVE: To determine the efficacy of 131I-6-beta-iodomethylnorcholesterol (NP-59) adrenal scintigraphy in distinguishing benign from malignant euadrenal masses. DESIGN: Case series of patients with incidentally discovered unilateral, euadrenal masses. SETTING: Referral-based nuclear medicine clinics at university and affiliated Veterans Administration medical centers. PATIENTS: Consecutive sample of 119 euadrenal patients with unilateral adrenal masses discovered on computed tomographic (CT) scans for reasons other than suspected adrenal disease. INTERVENTIONS: Adrenal scintiscans done using 1 mCi of NP-59 intravenously, and gamma camera imaging 5 to 7 days later. MEASUREMENTS AND MAIN RESULTS: Mean lesion diameter was 3.3 +/- 1.9 cm (SD) (95% CI: 2.9 to 3.6 cm). In 76 patients, NP-59 uptake lateralized to the abnormal adrenal seen on CT scans (concordant imaging), and in all of these patients, a diagnosis of adenoma was made by needle-aspiration biopsy, adrenalectomy, or extended follow-up with repeat CT scans that were unchanged at 6 months or later. Twenty-six patients had absent or markedly reduced NP-59 uptake in the glands identified as abnormal on CT scans (discordant imaging). These adrenal masses proved to be metastatic malignancies in 19 patients, primary adrenal neoplasms other than adenoma in 4, and adrenal cysts in 3. Bilateral, symmetric accumulation of NP-59 was seen in 17 patients, in whom the adrenal masses were shown to be metastatic malignancies in 2, and adenomas in 6 (the lesions in these cases being 2 cm or less in diameter), and lesions not truly involving the adrenal in the rest (periadrenal metastases in 4 and pseudoadrenal masses in 5). Sensitivity was 76% (26 of 34 patients; CI, 58% to 88%); specificity, 100% (85 of 85 patients; CI, 95% to 100%), and accuracy, 93% (111 of 119 patients: CI, 88% to 98%). CONCLUSIONS: Functional NP-59 scintigraphy can be used to accurately and noninvasively characterize many euadrenal masses; concordance of CT and NP-59 scans can be used to exclude the presence of a malignancy or other space-occupying adrenal lesion.

Functional and scintigraphic evaluation of the silent adrenal mass.

Seven patients with unilateral and one patient with bilateral and asymmetric (R greater than L) incidentally discovered adrenal mass abnormalities depicted by computed tomography (CT) were studied by 131I-6 beta-iodomethyl-19-norcholesterol (NP-59) scintigraphy. There was marked lateralization of NP-59 uptake to the side of the mass lesion in the seven patients with unilateral masses and prominent asymmetric, (R greater than L) bilateral uptake in the patient with bilateral masses despite the fact that there were no obvious abnormalities of adrenocortical or adrenomedullary function as determined from peripheral blood and 24-hr urinary hormone measurements. Simultaneous bilateral adrenal vein catheterization (AVC) was employed to measure the levels of hormone effluent from the adrenal cortex and medulla and in all instances the cortisol concentrations were greatest from the side of the mass lesion in those patients with unilateral masses and from the larger of the two adrenals in the patient with bilateral adrenal masses. Thus, there was congruence between the anatomic (CT) and functional (NP-59 scintigraphy and AVC) investigations that depicted asymmetry of the adrenal glands which were not associated with abnormalities of overall adrenal function or hypothalamic-pituitary-adrenal axis integrity.

Comparison of mediastinal width, mediastinal-thoracic and -cardiac ratios, and "mediastinal widening" in detection of traumatic aortic rupture.

This study was undertaken to determine whether direct measurement of mediastinal width or computation of ratios of measurements of easily detectable mediastinal structures is more effective than the subjective impression of "mediastinal widening" in selecting trauma patients for aortography. A group of five surgeons and radiologists individually read in blinded fashion 149 chest films of trauma victims who had undergone aortography to rule out traumatic rupture of the aorta (TRA). Each made a subjective interpretation of "mediastinal widening," as well as direct measurement of mediastinal width (MW), thoracic width at the level of the mediastinum, cardiac width, and maximum thoracic width. Mediastinal-cardiac (MC), mediastinal-thoracic (MT), and mediastinal-mediastinothoracic (MMT) ratios were calculated. Statistically significant differences were found in all parameters of direct measurement between cases with and without TRA (P from .0001 for MT to .01 for MMT). The critical measurement for mediastinal width separating positive from negative cases was 8.0 cm; the critical ratios were MT = 0.275, MC = 0.555, and MMT = 0.36. Application of these parameters to detect TRA yielded sensitivities of .75 for MW, .68 for MC, .66 for MMT, and .62 for MT. Statistically significant differences between observers' measurements were seen. None of these measurements was as effective as subjective interpretation of mediastinal widening, which had a sensitivity of .91 (P = .0000). We conclude that the subjective impression of mediastinal widening is superior to "objective" direct measurement of mediastinal structures for identification of trauma patients with aortic rupture.

Assessment of mediastinal widening associated with traumatic rupture of the aorta.

In order to best determine the reliability and usefulness of widening of the mediastinum (WMED) and other radiographic abnormalities in the selection of trauma patients for aortography to detect traumatic rupture of the aorta (TRA), we designed a blind study in which a panel of radiologists and surgeons reviewed 149 chest films of trauma victims who subsequently underwent aortography to rule out TRA. Sixteen patients had TRA. Panelists identified mediastinal widening (WMED) in 83 of 93 observations on films in cases of TRA (89%). There was a significant association between WMED and TRA found both for the panel as a whole and for each panelist individually (p = 0.0000), making this an extremely reliable sign both in terms of detectability and in signalling the need for aortography. Significant associations with TRA were also found overall for six other radiographic abnormalities but none of these was reliable for all panelists or was as sensitive as WMED in the detection of TRA. Despite the reliability of these signs, panelists making decisions based on the chest film alone failed to recommend aortography in seven of 93 instances of TRA. Direct mediastinal measurements varied by at least 2 cm among panelists in one half of the cases of TRA, and 25% of these (4/16) had at least two measurements of mediastinal width of 7 cm or less. Of all the radiographic signs associated with TRA, widening of the mediastinum is the most reliable, but in this study all observers would not have detected all cases of ruptured aorta using radiographic signs alone. Clinical judgment and consideration of the forces involved in the injury must continue to play an important role in the selection of patients for aortography.