Incidentaloma MRI: Difference between revisions
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{{Incidentaloma}} | {{Incidentaloma}} | ||
{{CMG}}; {{AE}} | {{CMG}}; {{AE}} {{MAD}} | ||
==Overview== | ==Overview== | ||
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* [[Benign]] [[adrenal]] [[Adrenal cortex|cortical]] adenomas lose signal on out-of-phase images but appear relatively bright on in-phase images.<ref name="pmid21997291">{{cite journal| author=Young WF| title=Conventional imaging in adrenocortical carcinoma: update and perspectives. | journal=Horm Cancer | year= 2011 | volume= 2 | issue= 6 | pages= 341-7 | pmid=21997291 | doi=10.1007/s12672-011-0089-z | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=21997291 }}</ref> | * [[Benign]] [[adrenal]] [[Adrenal cortex|cortical]] adenomas lose signal on out-of-phase images but appear relatively bright on in-phase images.<ref name="pmid21997291">{{cite journal| author=Young WF| title=Conventional imaging in adrenocortical carcinoma: update and perspectives. | journal=Horm Cancer | year= 2011 | volume= 2 | issue= 6 | pages= 341-7 | pmid=21997291 | doi=10.1007/s12672-011-0089-z | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=21997291 }}</ref> | ||
* 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 [[Pheochromocytoma|pheochromocytomas]] (but also [[lipid]]-poor [[Adrenal gland|adrenal]] [[Adenoma|adenomas]]) that all lack intracellular [[lipid]] remain unchanged.<ref name="pmid15118113">{{cite journal| author=Haider MA, Ghai S, Jhaveri K, Lockwood G| title=Chemical shift MR imaging of hyperattenuating (>10 HU) adrenal masses: does it still have a role? | journal=Radiology | year= 2004 | volume= 231 | issue= 3 | pages= 711-6 | pmid=15118113 | doi=10.1148/radiol.2313030676 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15118113 }}</ref> | * 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 [[Pheochromocytoma|pheochromocytomas]] (but also [[lipid]]-poor [[Adrenal gland|adrenal]] [[Adenoma|adenomas]]) that all lack intracellular [[lipid]] remain unchanged.<ref name="pmid15118113">{{cite journal| author=Haider MA, Ghai S, Jhaveri K, Lockwood G| title=Chemical shift MR imaging of hyperattenuating (>10 HU) adrenal masses: does it still have a role? | journal=Radiology | year= 2004 | volume= 231 | issue= 3 | pages= 711-6 | pmid=15118113 | doi=10.1148/radiol.2313030676 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15118113 }}</ref> | ||
[[File:MRI adrenal adenoma.gif|left|300px|thumb|MRI shows left adrenal mass with loss of signal on out-of-phase imaging, source; Case courtesy of A.Prof Frank Gaillard, Radiopaedia.org, rID: 2600]] | |||
==References== | ==References== | ||
Revision as of 16:59, 28 August 2017
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Mohammed Abdelwahed M.D[2]
Overview
Adrenal MRI may be helpful in the diagnosis of incidentaloma. Findings on MRI suggestive of incidentaloma include mild enhancement and a rapid washout of contrast, while malignant lesions show rapid and marked enhancement and a slower washout pattern. 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.
MRI
- Adrenal MRI may be helpful in the diagnosis of incidentaloma. Findings on MRI suggestive of/diagnostic of incidentaloma include:
- T1 and T2-weighted imaging can distinguish benign adenomas from malignancy and pheochromocytoma.[1]
- 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.[2]
- 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.[3]
- Chemical shift imaging relies on the fact that, within magnetic fields, protons in water vibrate at a slightly different frequency than protons in lipid.[4]
- 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.[5]
- 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.[6]
References
- ↑ 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.
- ↑ Peppercorn PD, Grossman AB, Reznek RH (1998). "Imaging of incidentally discovered adrenal masses". Clin Endocrinol (Oxf). 48 (4): 379–88. PMID 9640401.
- ↑ Sahdev A, Reznek RH (2004). "Imaging evaluation of the non-functioning indeterminate adrenal mass". Trends Endocrinol Metab. 15 (6): 271–6. doi:10.1016/j.tem.2004.06.012. PMID 15358280.
- ↑ 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.
- ↑ Haider MA, Ghai S, Jhaveri K, Lockwood G (2004). "Chemical shift MR imaging of hyperattenuating (>10 HU) adrenal masses: does it still have a role?". Radiology. 231 (3): 711–6. doi:10.1148/radiol.2313030676. PMID 15118113.