Pitfalls of adrenal imaging with chemical shift MRI

Comparison of Quantitative MRI and CT Washout Analysis for Differentiation of Adrenal Pheochromocytoma From Adrenal Adenoma

“…The reference standard for adrenal adenoma could not be practically obtained from histopathologic records but was established through a combination of typical imaging findings (unenhanced CT attenuation < 10 HU, chemicalshift signal intensity [SI] index greater than 16.5%, or absolute and relative CT washout greater than 60% and 40% [7]), by documentation of a minimum of 1 year of interval stability in size, and by the absence of biochemical evidence of pheochromocytoma. Twenty-nine patients with 29 adenomas were identified who underwent MRI, nine patients with nine adenomas who underwent washout CT, and one patient with one adenoma who underwent both MRI and washout CT. No patient in the adenoma group had a history of primary malignancy.…”

“…An unenhanced CT attenuation threshold of less than 10 HU is highly accurate for the diagnosis of adenoma [13]. However, a proportion of adenomas have insufficient intracellular lipid to measure less than 10 HU [7], and low-density pheochromocytomas have also been found during CT [14]. It has been previously found [15][16][17] that there is substantial overlap between the two lesions with respect to washout CT criteria.…”

“…Similarly, adrenal cortical carcinoma (ACC) is also rare and usually large (> 4 cm), often presenting with systemic spread of disease [5,6]. The diagnosis of myelolipoma is readily established by detecting the presence of macroscopic fat [7]. Therefore, the OBJECTIVE.…”

Multiparametric MRI of solid renal masses: pearls and pitfalls

“…34 At 3 T, because the first OP echo occurs at 1.1 ms, sampling the first echo pair is challenging and requires high receiver bandwidths. 34e36 This technical limitation can be overcome 34 ; however, sampling the first IP and later OP echoes should not be performed because SI drop on the OP images could be due to either intralesional fat or susceptibility (T2*) effects 34,37 (Fig 6).…”

Current Management of Adrenal Incidentalomas

“…Therefore, lipid-rich adenomas show loss of signal on out-of-phase imaging, while lipid-poor adenomas display modest signal loss. In equivocal cases, a relative drop in signal compared with the spleen establishes the presence of microscopic fat to help diferentiate adenomas [11]. Benign adrenal adenomas are usually iso-or hypointense on T2 weighted images.…”