Characterization of adrenal adenomas and metastases: correlation between unenhanced computed tomography and chemical shift magnetic resonance imaging

Abstract

Since CS MR imaging and CT both depict the presence of lipids within adrenal lesions, absolute attenuation values are highly correlated with MR quantitative analysis. SI-i is the most reliable tool for differentiating adrenal adenomas from metastases, showing better accuracy than lesion-to-spleen CS-r, in particular for adenomas with indeterminate absolute attenuation values.

Adrenal MRI: Techniques and clinical applications

“…1a,b). Other investigators subsequently confirmed the value of this technique (12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23).…”

“…If one wanted to perform a quantitative measurement of adrenal lesion lipid then the chemical shift index can be calculated (21). The chemical shift index is defined as follows: A chemical shift index of >15%-20% detects most lipid-containing adrenal adenomas with high specificity (13,23,25). Rarely, lipid containing adrenal metastases can occur are exceptions to this rule.…”

Quantitative evaluation of norcholesterol scintigraphy, CT attenuation value, and chemical-shift MR imaging for characterizing adrenal adenomas

“…The usefulness of radiocholesterol, CT, and MRI for the detection and differential diagnosis of adrenal masses has been discussed, but comparison of the qualitative properties of these three imaging modalities has not been extensively reported in the literature [2,8,13,20]. In our patients with functioning adenomas, the overall sensitivities of norcholesterol uptake on scintigraphy, attenuation value on CT, and suppression index on MRI were around 80% for each of the three.…”

“…In the qualitative diagnosis of adrenal masses, differentiating adrenal adenomas from other adrenal masses is critical because it can reduce the need for further invasive examinations and long-term follow-up imaging [1,2].…”

Should we use CT or MRI for detection and characterization of benign adrenal lesions?

“…2,3 Despite of frequent use of CT and MRI in clinical practice, there are limited data in the literature showing which technique is more sensitive in detection of benign adrenal lesions, and which one should be preferred for their characterization. Moreover, most of the papers on this topic are concentrated on characterization of adenomas only, 4,5 or were published before the era of contemporary multidetector CT and high magnetic field strength MRI scanners. 6,7 According to American College of Radiology (ACR) Appropriateness Criteria, CT and MRI are rated equally appropriate for the initial evaluation and follow-up of incidentally discovered adrenal masses >1 cm, but there are no data for determining the accuracy of imaging for masses measuring less than 1 cm.…”