Radiology Notes

My notes during radiology residency, fellowship, and beyond…

Archive for the ‘adrenal’ Category

Adrenal Mass Differential

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  • Lipid rich adenoma = fat density
  • Adrenocortical carcinoma
  • Pheochromocytoma = bright on T2; light bulb
  • Myelolipoma
  • Lymphoma
  • Metastasis

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Written by lmwong

January 16, 2010 at 11:11 am

Adrenal Carcinoma

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  • large 4-20 cm
  • areas of central necrosis and hemorrhage
  • irregular enhancement
  • delay CECT shows poor washout
  • liver and lymph nodes metastasis
  • invasion in renal vein or IVC
  • MR: low T1, high T2

Written by lmwong

May 24, 2008 at 2:23 pm

Posted in abdomen, adrenal, gi, tumor

Adrenal Metastasis

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  • very common
  • lung, breast, melanoma, GI, renal
  • small lesions less than 3-4 cm cannot distinguish from benign
  • larger lesions are inhomogenous, progressive enhancement, irregular outline, thick rim, local invasion
  • poor contrast washout on 15 minute delays

Written by lmwong

May 24, 2008 at 2:19 pm

Benign Adrenal Lesions

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  1. Adrenal hyperplasia
    • 70/20 = Cushings/Conn
    • treat medically
    • half have normal CT findings
    • usually diffuse enlargement, rarely nodular
  2. Adrenal Adenoma
    • functional or nonfunctional
    • cured by excision
    • small, less than 4 cm, round, well-defined
    • fat density
    • CT: less than 10 HU on noncontrasted images, greater than 50% washout (below)
    • MR: iso/hypo on T1, iso/hyper on T2 to liver, drops with OP (fat)
  3. Adreanl Myelopilomas
    • rare, nonfunctioning tumors
    • from bone-marrow elements
    • no malignant potential
    • mixed components, 20% calcifications
    • up to 30 cm in size
    • macroscopic fat is pathogneumonic; MR fat sat, CT -30 HU
  4. Adrenal hemorrhage
    • newborn infants
      • hypoxia, birth trauma, septicemia, child abuse
      • bilateral
    • adults
      • trauma and infection
      • unilateral (right side)
    • CT: hypodense on CECT to liver and spleen, stranding
    • MR: acute iso T1 low T2, subacute high T1 high or low T2, old low on T1 and T2
    • US: hypoechoic mass that shrinks and becomes less echogenic over time.
  5. Adrenal cysts
    • benign: less than 6 cm, homogenous, fluid density/intensity
    • complicated: greater than 6 cm, inhomnogenous, debris, from hemorrhage, or cystic tumor degeneration

Adrenal Protocol CT:

  • noncontrast scan
  • contrasted scan, measure HU
  • 15 delay, should see greater than 50% washout
  • otherwise, leww likely benign, get biopsy

Written by lmwong

May 24, 2008 at 1:53 pm

Endocrine Syndromes

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Adrenal Gland

  • Cortex: cortisol, aldosterone, androgens, estrogens
  • Medulla: catecholamines

Cushing Syndrome

  • hypersecretion of hydrocortisone and cortisterone
  • truncal obesity, easy bruisability, weakness, diabetes mellitus, oligomenorrhea
  • adrenal hyperplasia
  • 20% from benign adenomas
  • 90% from pituitary macroadenoma (+ACTH production); get MR of sella
  • 10% from lung malignancies

Conn Syndrome

  • hypersecretion of aldosterone
  • hypertension, hypokalemia, increased serum and urine aldosterone, decreased renin
  • 80% solitary benign hyperfunctioning adrenal adenoma
  • 20% from adrenal hyperplasia

Adrenogenital Syndrome

  • newborns and infants
  • 11b or 22-hydroxylase deficiency
  • deficiency cortisol and aldosterone, excess precursor androgens
  • masculizing or feminizing syndromes
  • adrenal hyperplasia

Addison disease

  • primary adrenal insufficiency
  • greater than 90% of cortex destroyed: idiopathic, TB, histoplasmosis, infarction, fungal, lymphoma, mets)


  • hypersecretion of catecholamines
  • paroxysmal attacks, HTN, headaches, tremors
  • Rule of 10s: 10% bilateral, extra-adrenal, malignant, and familial
  • Associated with MEN II, VHL, NF
  • most larger than 2 cm
  • solid, complex, to cystic
  • rare calficiations (eggshell)
  • Get CT first, if no adrenal lesion found, image chest and abdomen. Extr-adrenal sites include organ of Zuckerkandl near bifurcatino of aorta, bladder, para-aortic sympathetic chain.
  • MR bright on T2, enhance with contrast, no IP/OP difference
  • MIBG on nuclear medicine
  • can hemorrhage spontaneously

Written by lmwong

May 24, 2008 at 1:29 pm

Posted in abdomen, adrenal, gi