Download Cushing`s Syndrome - Diagnostic Imaging Pathways

Diagnostic Imaging Pathways - Cushing's Syndrome
Printed from Diagnostic Imaging Pathways
www.imagingpathways.health.wa.gov.au
© Government of Western Australia
Diagnostic Imaging Pathways - Cushing's Syndrome
Population Covered By The Guidance
This pathway provides guidance on the imaging of adult patients with Cushing's syndrome.
Date reviewed: January 2012
Date of next review: January 2015
Published: January 2012
Quick User Guide
Move the mouse cursor over the PINK text boxes inside the flow chart to bring up a pop up box with salient
points.
Clicking on the PINK text box will bring up the full text.
The relative radiation level (RRL) of each imaging investigation is displayed in the pop up box.
SYMBOL
RRL
None
EFFECTIVE DOSE RANGE
0
Minimal
< 1 millisieverts
Low
1-5 mSv
Medium
5-10 mSv
High
>10 mSv
Pathway Diagram
1/7
Phoca PDF
Diagnostic Imaging Pathways - Cushing's Syndrome
Printed from Diagnostic Imaging Pathways
www.imagingpathways.health.wa.gov.au
© Government of Western Australia
Image Gallery
Note: These images open in a new page
1a
Cushing's Disease
Image 1a and b (Magnetic Resonance Imaging): There is a right sided
pituitary adenoma (arrows) measuring up to 14mm with deviation of the stalk
to the left. Slight suprasellar extension is noted without impingement of the
chiasm or optic nerves.
1b
2/7
Phoca PDF
Diagnostic Imaging Pathways - Cushing's Syndrome
Printed from Diagnostic Imaging Pathways
www.imagingpathways.health.wa.gov.au
© Government of Western Australia
2a
Pituitary Macroadenoma
Image 2a and 2b: Post-mortem specimens showing a circumcribed nodular
tumour arising from the anterior pituitary consistent with a macroadenoma.
2b
2c
Image 2c (H&E, x2.5) and 2d (H&E, x20): Histological sections
demonstrating a circumscribed lesion composed of sheets of uniform
polygonal cells with centrally placed nuclei and amphophilic cytoplasm. The
features are consistent with a pituitary adenoma.
2d
Teaching Points
Once Cushing's Syndrome is confirmed biochemically, further imaging is dictated by the ACTH
ACTH suppressed – Likely primary adrenocortical lesion and CT scan of the adrenals is
required
ACTH normal or high – Either pituitary disease or ectopic source of ACTH. Further
biochemical testing with dexamethasone suppression may help differentiate the two causes
prior to imaging
Suppressed ACTH Levels
A low or undetectable level of ACTH suggests primary adrenocortical disease and in such cases,
CT of the adrenals is the investigation of choice 1,2,3,4
ACTH Dependant Cushing's Syndrome
Once Cushing's syndrome is confirmed biochemically, imaging is directed by the measurement of
ACTH levels 1,2,3,4
When plasma ACTH and cortisol levels are increased, this suggests an ACTH dependant cause of
Cushing's syndrome. Further evaluation is based on the 'High-Dose Dexamethasone Suppression
Test'
If ACTH is suppressed pituitary disease is the most likely diagnosis and MRI of the pituitary
3/7
Phoca PDF
Diagnostic Imaging Pathways - Cushing's Syndrome
Printed from Diagnostic Imaging Pathways
www.imagingpathways.health.wa.gov.au
© Government of Western Australia
is indicated 1,2,3,4
When the biochemistry data suggests an ectopic ACTH syndrome, a CT scan of the
abdomen and chest should be performed as the initial radiographic evaluation for the
variety of tumours responsible for this syndrome 1,2,3,4
Computed Tomography (CT) of the Abdomen and Chest in Ectopic
Cushing's Syndrome
A radiological search for occult ACTH producing tumour should only be made after exclusion of
Cushing's disease 14
40-50% of functioning pituitary microadenoma's may not be visible on MRI
Inferior petrosal sampling should be undertaken to exclude a pituitary cause of hypercortisolism
(not visible on conventional MRI) prior to a radiological search for an ectopic ACTH-secreting
tumour 14
Imaging of the thorax and abdomen with computed tomography will yield the highest detection rate
in searching for an occult ACTH-secreting neoplasm 14
Computed Tomography (CT) of the Adrenal Glands
Most sensitive method for finding adrenal tumour in a patient with ACTH-independent Cushing's
syndrome 1,2,3,4
As the size of the adrenal mass is the most important feature distinguishing benign adenoma from
adrenocortical carcinoma, a CT scan is all that is required in most cases 12
May differentiate between adenoma and hyperplasia, but hyperplastic adrenal glands have a
variable appearance and CT diagnosis of adrenal hyperplasia is not very reliable 1,2,3,4
Nodularity and bilateral gland enlargement suggests hyperplasia
Nodule and contralateral atrophy suggests functioning adenoma
Nodule in otherwise normal gland may be either hyperplasia or functioning adenoma
Causes of Cushing's Syndrome
Evaluation of the patient with suspected Cushing's syndrome begins with a 24 hour urinary cortisol
13
Cushing's disease (excessive production of ACTH) is the most common aetiology, accounting for
65-75% of Cushing's syndrome. Most cases of Cushing's Disease are result of pituitary adenomas
1
Ectopic production of ACTH from a variety of tumours (bronchial carcinoid, thymoma, oat-cell
carcinoma, phaeochromocytoma, islet cell tumour, and prostate cancer) accounts for 10-15% of
Cushing syndrome 1
Primary adrenocortical disease accounts for the remaining 20-30% of Cushing's syndrome,
including benign adenoma (10-15%), adrenocortical carcinoma (5-10%) and adenomatous
hyperplasia (5%) 1
Magnetic Resonance Imaging (MRI) of the Pituitary Gland
4/7
Phoca PDF
Diagnostic Imaging Pathways - Cushing's Syndrome
Printed from Diagnostic Imaging Pathways
www.imagingpathways.health.wa.gov.au
© Government of Western Australia
MRI is the imaging modality of choice for localisation of pituitary adenoma in pituitary-dependent
Cushing's disease (53-75% sensitivity for detecting corticotroph tumour) 5-9
MRI, with the addition of gadolinium, facilitates diagnosis of microadenoma and increases the
confidence with which cavernous sinus invasion can be diagnosed or excluded 9,10
Advantages of MRI - superior soft tissue resolution (depicts the anatomy of the pituitary gland,
infundibulum, optic chiasm, cavernous sinuses and neighbouring vascular structures accurately
and noninvasively) 5-9
Disadvantages of MRI - expensive and limited availability
CT has a 47% sensitivity and 74% specificity for the identification of pituitary microadenomas and
most commonly reveals a hypodense lesion that usually fails to enhance with contrast
administration 5,6
Petrosal sinus sampling may be indicated in patients with clinically suspected pituitary
microadenoma but normal MRI 1-5,11
References
References are graded from Level I to V according to the Oxford Centre for Evidence-Based Medicine,
Levels of Evidence. Download the document
1. Goldfarb DA. Contemporary evaluation and management of Cushing's syndrome. World J
Urol. 1999;17:22-5. (Review article)
2. Boscharo M, Barzon L, Fallo F, et al. Cushing's syndrome. Lancet. 2001;357:783-91. (Review
article)
3. Newell-Price J, Jorgensen JOL, Grossman A. The diagnosis and differential diagnosis of
Cushing's syndrome. Hormone Research. 1999;51(S3):81-94. (Review article)
4. Ross RJM, Trainer PJ. Endocrine investigation: Cushing's syndrome. Clin Endocrinol (Oxf).
1998;49:153-5. (Review article)
5. Kaye TB, Crapo L. The Cushing syndrome: an update on diagnostic tests. Ann Intern Med.
1990;112:434-44. (Level II evidence). View the reference
6. Buchfelder M, Nistor R, Fahlbusch R, et al. The accuracy of CT and MR evaluation of the sella
turcica for detection of adrenocorticotropic hormone-secreting adenomas in Cushing
disease. AJNR Am J Neuroradiol. 1993;14:1183-90. (Level III evidence)
7. Peck WW, Dillon WP, Norman D, et al. High resolution MR imaging of pituitary
microadenomas at 1.5T: experience with Cushing's disease. AJR Am J Roentgenol.
1989;152:145-51. (Level III evidence)
8. De Herder WW, Uitterlinden P, Pieterman H, et al. Pituitary tumour localisation in patients with
Cushing's disease by magnetic resonance imaging: is there a place for petrosal sinus
sampling? Clin Endocrinol (Oxf). 1994;40:87-92. (Level III evidence)
9. Colombo N, Loli P, Vignati F, et al. MR of corticotropic-secreting pituitary microadenomas.
AJNR Am J Neuroradiol. 1994;15:1591-5. (Level IV evidence)
10. Doppman JL, Frank JA, Dwyer AJ, et al. Gadolinium DTPA enhanced MR imaging of ACTHsecreting microadenomas of the pituitary gland. J Comput Assist Tomogr. 1988;12:728-35.
(Level IV evidence)
11. Oldfield EH, Doppman JL, Nieman LK, et al. Petrosal sinus sampling with and without
corticotropin-releasing hormone for the differential diagnosis of Cushing's syndrome. N
Engl J Med. 1991;325;897-905. (Level III evidence)
12. Daitich JA, Goldfarb DA, Novick AC. Cleveland clinic experience with adrenal Cushing's
syndrome. J Urol. 1997;158:2051-5. (Level III evidence)
13. Mengden T, Hubmann P, Muller J et al. Urinary free cortisol versus 17-hydroxycorticosteroids:
a comparative study of their diagnostic value in Cushing's Syndrome. Clinical Invest. 1992;
5/7
Phoca PDF
Diagnostic Imaging Pathways - Cushing's Syndrome
Printed from Diagnostic Imaging Pathways
www.imagingpathways.health.wa.gov.au
© Government of Western Australia
70(7): 545-8. (Level III evidence)
14. Findling J, Raff Hershel. Cushing's syndrome: important issues in diagnosis and
management. J Clin Endocrinol Metab. 2006;91(10):3746-53. (Review article)
Further Reading
1. Cushing's syndrome. Current Probl Surg. July 2001;489-545. (Review article)
Information for Consumers
Information from this website
Information from the Royal
Australian and New Zealand
College of Radiologists’ website
Consent to Procedure or Treatment
Computed Tomography (CT)
Radiation Risks of X-rays and Scans
Contrast Medium (Gadolinium versus
Iodine)
Computed Tomography (CT)
Gadolinium Contrast Medium
Magnetic Resonance Imaging (MRI)
Iodine-Containing Contrast Medium
Magnetic Resonance Imaging (MRI)
Radiation Risk of Medical Imaging During
Pregnancy
Radiation Risk of Medical Imaging for
Adults and Children
Copyright
© Copyright 2015, Department of Health Western Australia. All Rights Reserved. This web site and its
content has been prepared by The Department of Health, Western Australia. The information contained on
this web site is protected by copyright.
Legal Notice
Please remember that this leaflet is intended as general information only. It is not definitive and The
Department of Health, Western Australia can not accept any legal liability arising from its use. The
information is kept as up to date and accurate as possible, but please be warned that it is always subject
to change
6/7
Phoca PDF
Diagnostic Imaging Pathways - Cushing's Syndrome
Printed from Diagnostic Imaging Pathways
www.imagingpathways.health.wa.gov.au
© Government of Western Australia
.
File Formats
Some documents for download on this website are in a Portable Document Format (PDF). To read these
files you might need to download Adobe Acrobat Reader.
Legal Matters
7/7
Powered by TCPDF (www.tcpdf.org)
Phoca PDF