Incidentaloma MRI: Difference between revisions
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{{Incidentaloma}} | {{Incidentaloma}} | ||
{{CMG}}; {{AE}} | {{CMG}}; {{AE}} {{MAD}} | ||
==Overview== | ==Overview== | ||
[[Adrenal gland|Adrenal]] [[Magnetic resonance imaging|MRI]] may be helpful in the diagnosis of incidentaloma. Findings on [[Magnetic resonance imaging|MRI]] suggestive of incidentaloma include mild enhancement and a rapid washout of [[Contrast medium|contrast,]] while [[malignant]] lesions show rapid and marked enhancement and a slower washout pattern. [[Magnetic resonance imaging|MRI]] has advantages in certain clinical situations. The advantages of [[Magnetic resonance imaging|MRI]] over [[Computed tomography|CT]] are its lack of radiation exposure, lack of [[iodine]]-based contrast media and its superior tissue contrast resolution. | |||
==MRI== | |||
*[[Adrenal gland|Adrenal]] [[Magnetic resonance imaging|MRI]] may be helpful in the diagnosis of incidentaloma.<ref name="pmid28181818">{{cite journal| author=Sahdev A| title=Recommendations for the management of adrenal incidentalomas: what is pertinent for radiologists? | journal=Br J Radiol | year= 2017 | volume= 90 | issue= 1072 | pages= 20160627 | pmid=28181818 | doi=10.1259/bjr.20160627 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=28181818 }}</ref> | |||
** [[Magnetic resonance imaging|MRI]] rather than [[Computed tomography|CT]] is suggested if [[Adrenal gland|adrenal]] imaging is required in children, adolescents, [[Pregnancy|pregnant]] females, and adults younger than 40 years of age. | |||
*Findings on [[Magnetic resonance imaging|MRI]] suggestive of incidentaloma include:<ref name="pmid9640401">{{cite journal| author=Peppercorn PD, Grossman AB, Reznek RH| title=Imaging of incidentally discovered adrenal masses. | journal=Clin Endocrinol (Oxf) | year= 1998 | volume= 48 | issue= 4 | pages= 379-88 | pmid=9640401 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=9640401 }}</ref><ref name="pmid15358280">{{cite journal| author=Sahdev A, Reznek RH| title=Imaging evaluation of the non-functioning indeterminate adrenal mass. | journal=Trends Endocrinol Metab | year= 2004 | volume= 15 | issue= 6 | pages= 271-6 | pmid=15358280 | doi=10.1016/j.tem.2004.06.012 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15358280 }}</ref> | |||
** T1 and T2-weighted imaging can distinguish [[benign]] [[adenomas]] from [[malignancy]] and [[pheochromocytoma]]. | |||
** [[Magnetic resonance imaging|MRI]] has advantages in certain clinical situations. The advantages of [[Magnetic resonance imaging|MRI]] over [[Computed tomography|CT]] are its lack of [[Radiation therapy|radiation]] exposure, lack of [[iodine]]-based [[Contrast medium|contrast media]] and its superior tissue contrast resolution. | |||
** On [[DTPA|gadolinium-diethylene triamine pentaacetic acid]] ([[DTPA]])-enhanced [[Magnetic resonance imaging|MRI]], [[adenomas]] demonstrate mild enhancement and a rapid washout of contrast, while [[malignant]] lesions show rapid and marked enhancement and a slower washout pattern. | |||
* T1 and T2-weighted imaging can distinguish benign adenomas from malignancy and pheochromocytoma. | |||
==== Chemical shift ==== | |||
* Chemical shift imaging relies on the fact that | * [[Chemical shift]] imaging relies on the fact that [[Proton|protons]] in water vibrate at a slightly different frequency than [[Proton|protons]] in [[lipid]].<ref name="pmid15208141">{{cite journal| author=Israel GM, Korobkin M, Wang C, Hecht EN, Krinsky GA| title=Comparison of unenhanced CT and chemical shift MRI in evaluating lipid-rich adrenal adenomas. | journal=AJR Am J Roentgenol | year= 2004 | volume= 183 | issue= 1 | pages= 215-9 | pmid=15208141 | doi=10.2214/ajr.183.1.1830215 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15208141 }}</ref><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><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> | ||
** By selecting appropriate sequencing parameters, separate images can be generated with water and [[fat]] [[Proton|protons]] oscillating in phase or out of phase to each other. | |||
** [[Benign]] [[adrenal]] [[Adrenal cortex|cortical]] adenomas lose signal on out-of-phase images but appear relatively bright on in-phase images. | |||
** Whereas [[malignant]] lesions, [[Pheochromocytoma|pheochromocytomas]], and [[lipid]]-poor [[Adrenal gland|adrenal]] [[Adenoma|adenomas]] remain unchanged because all lack intracellular [[lipid]]. | |||
[[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]] | |||
* | <br style="clear:left"> | ||
==References== | ==References== | ||
Latest revision as of 15:49, 9 November 2017
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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: 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
- Findings on MRI suggestive of incidentaloma include:[2][3]
- T1 and T2-weighted imaging can distinguish benign adenomas from malignancy and pheochromocytoma.
- 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.
- 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
- Chemical shift imaging relies on the fact that protons in water vibrate at a slightly different frequency than protons in lipid.[4][5][6]
- 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.
- Whereas malignant lesions, pheochromocytomas, and lipid-poor adrenal adenomas remain unchanged because all lack intracellular lipid.
References
- ↑ Sahdev A (2017). "Recommendations for the management of adrenal incidentalomas: what is pertinent for radiologists?". Br J Radiol. 90 (1072): 20160627. doi:10.1259/bjr.20160627. PMID 28181818.
- ↑ 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.