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Radiology Endocrine System a2e2a27b

Light bulb appearance in MRI scan is/are seen in:

A
Pheochromocytoma
B
Adrenal adenoma
C
Adrenal cortical tumor
D
Adrenal calcification
High-Yield Explanation
Ans: A (Pheochromocytoma) PHAEOCHROMQCYTOMA light bulb sign on MRI: The tumor is characterized on MRI by low signal intensity on T1-weighted images and extremely high signal intensity', the "light bulb sign," on T2-weighted images. The tumor is characterized on MRI by low signal intensity on T1-weighted images and extremely high signal intensity, the light bulb sign," on T2-weighted images http:// w'ww. diagnosticimaging.com/articles/ct-and-mri-help-evahiate-adrenal- gland-disordersiisth ash. 7Avnpf2x.dpuf"Pheochromocytomas and other paragangliomas classically have a "light bulb" (very intense) appearance on T2-weighted images"ADRENAL IMAGING : MRi www,ajronline.ory/,,./A}R.10.4547# ACCs (adreno cortical carcinoma) are seen as heterogeneous on both Tl- and T2-weighted imaging because of hemorrhage and necrosis . Necrotic areas can have high signal intensity on T2-weighted imaging, and blood products can result in areas of high signal intensity within the lesion on Tl-weighted imaging. ACC can contain foci of intracytoplasmic lipid, which results in a loss of signal intensity on out-of-phase images# "Up to 70% of pheochromocytomas show relatively high signal intensity on T2-weighted images--a feature classically known as the light bulb sign, which was originally thought to be characteristic of pheochromocytoma. Currently, however, that description is not considered accurate, with at least 30% of pheochromocytomas showing moderate or low T2-weighted signal intensity and appearing similar to other adrenal disease# "Adrena adenoma': iso/hypoT2MRI (rarely hyperintense)"- Danhert Radiology Review Manual 5th/ 936

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