Incidentaloma MRI
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Incidentaloma Microchapters |
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Incidentaloma MRI On the Web |
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American Roentgen Ray Society Images of Incidentaloma MRI |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief:
Overview
There are no MRI findings associated with [disease name].
OR
[Location] MRI may be helpful in the diagnosis of [disease name]. Findings on MRI suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].
OR
There are no MRI findings associated with [disease name]. However, a MRI may be helpful in the diagnosis of complications of [disease name], which include [complication 1], [complication 2], and [complication 3].
MRI
- [Location] MRI may be helpful in the diagnosis of [disease name]. Findings on MRI suggestive of/diagnostic of [disease name] include:
MRI has advantages in certain clinical situations. The advantages of MRI over CT are its lack of radiation exposure, lack of iodine-based contrast media and its superior tissue contrast resolution.[1]
- T1 and T2-weighted imaging can distinguish benign adenomas from malignancy and pheochromocytoma.
- On gadolinium-diethylene triamine pentaacetic acid (DTPA)-enhanced MRI, adenomas demonstrate mild enhancement and a rapid washout of contrast, while malignant lesions show rapid and marked enhancement and a slower washout pattern.
- Chemical shift imaging relies on the fact that, within magnetic fields, protons in water vibrate at a slightly different frequency than protons in lipid.[2]
- As a result, water and fat protons oscillate in and out of phase with respect to one another.
- By selecting appropriate sequencing parameters, separate images can be generated with water and fat protons oscillating in phase or out of phase to each other.
- Benign adrenal cortical adenomas lose signal on out-of-phase images, but appear relatively bright on in-phase images.[3]
- (60, 61, 62, 63, 64, 65)
- With a high content of intracellular lipid usually lose signal intensity on out-of-phase images compared with in-phase images, whereas malignant lesions and pheochromocytomas (but also lipid-poor adrenal adenomas) that all lack intracellular lipid remain unchanged (58, 65, 66).
References
- ↑ Peppercorn PD, Grossman AB, Reznek RH (1998). "Imaging of incidentally discovered adrenal masses". Clin Endocrinol (Oxf). 48 (4): 379–88. PMID 9640401.
- ↑ Israel GM, Korobkin M, Wang C, Hecht EN, Krinsky GA (2004). "Comparison of unenhanced CT and chemical shift MRI in evaluating lipid-rich adrenal adenomas". AJR Am J Roentgenol. 183 (1): 215–9. doi:10.2214/ajr.183.1.1830215. PMID 15208141.
- ↑ Young WF (2011). "Conventional imaging in adrenocortical carcinoma: update and perspectives". Horm Cancer. 2 (6): 341–7. doi:10.1007/s12672-011-0089-z. PMID 21997291.