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Adrenal: Adrenal Adenoma Imaging Pearls - Learning Modules | CT Imaging | CT Scan Protocols - CTisus
Imaging Pearls ❯ Adrenal ❯ Adrenal Adenoma
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  • “The characteristic CT findings of adrenal adenoma with the maximal diameter greater than 5 cm include bulky, well-circumscribed, rounded or ovoid masses, heterogeneous attenuation with low-attenuation foci on non-enhanced CT images and heterogeneous enhancement after contrast administration. The differential diagnosis between such tumor and adrenal cortical carcinoma by CT examination is relatively difficult, such findings as recurrence, metastasis and venous tumor emboli may be of some significance.”

    Adrenal cortical adenoma with the maximal diameter greater than 5 cm: can they be differentiated from adrenal cortical carcinoma by CT?
    Tian L et al.
    Int J Clin Exp Med. 2014 Oct 15;7(10):3136-43. 
  • “The maximal diameter of the 14 masses of adenoma ranged from 5.5 cm to 20 cm (mean, 10 cm). One mass showed lobulated, the rest 13 masses showed rounded or ovoid. Eleven and 3 masses appeared well-circumscribed and ill-circumscribed, respectively. All of 14 masses presented heterogeneous density on non-enhanced CT images with patchy low-attenuation foci or stippled calcification. All of 14 masses revealed moderately to markedly heterogeneous enhancement after contrast administration.”

    Adrenal cortical adenoma with the maximal diameter greater than 5 cm: can they be differentiated from adrenal cortical carcinoma by CT?
    Tian L et al.
    Int J Clin Exp Med. 2014 Oct 15;7(10):3136-43. 
  • “ None of 14 masses developed local invasion and distant metastasis. Except for recurrence, metastasis and venous tumor emboli which only occurred in the cases of adrenal carcinoma, no definite computed tomographic features could be found that enabled the identification of adenomas with the maximal diameter greater than 5 cm with adrenal carcinomas.”

    Adrenal cortical adenoma with the maximal diameter greater than 5 cm: can they be differentiated from adrenal cortical carcinoma by CT?
    Tian L et al.
    Int J Clin Exp Med. 2014 Oct 15;7(10):3136-43.
  • “ MRI is equivalent to CT for characterizing adenomas measuring 20 HU or less on unenhanced CT. However, MRI is inferior to CT for adenomas measuring more than 20 HU because of decreased MR sensitivity.”
    Characterization of Lipid Poor Adrenal Adenoma: Chemical Shift MRI and Washout CT
    Seo JM et al.
    AJR 2014;202:1043-1050 
  • “ The sensitivities for adenomas measuring 20 HU or less on unenhanced CT were 100% in both MRI and CT, whereas those measuring more than 20 HU were 64% (16/25) and 100% (25/25) in MRI and CT , respectively.”
    Characterization of Lipid Poor Adrenal Adenoma: Chemical Shift MRI and Washout CT
    Seo JM et al.
    AJR 2014;202:1043-1050
  • “ A cutoff value of 10 HU provides sensitivity of 71% and specificity of 98%. Therefore, approximately 70% of adenomas can be correctly diagnosed on unenhanced CT without the use of IV contrast material. The remaining 30% of adenomas, however, require another imaging modality for characterization.”
    Characterization of Lipid Poor Adrenal Adenoma: Chemical Shift MRI and Washout CT
    Seo JM et al.
    AJR 2014;202:1043-1050
  • Adrenal Insufficiency
    -Bilateral hemorrhage à adrenal insufficiency
    -Nonspecific symptoms
    -Fatigue, weakness, muscle/joint pain
    -Abdominal pain, vomiting, diarrhea
    -Depression, behavioral changes
    -Hypotension
  • Adenoma with Hemorrhage
    -Rarely an adenoma can hemorrhage
    -Usually anticoagulated patient
    -Heterogeneous
    -Regions of high attenuation

     

  • "In clinical practice therefore, 10 HU is the most widely used threshold value for the diagnosis of lipid-rich adrenal adenoma."

    Adrenal Imaging
    Blake MA et al.
    AJR 2010; 194:1450-1460

     

  • "In conclusion the 10 minute delayed adrenal enhancement washout tests have reduced sensitivity for the detection of adenomas compared with results from prior studies, and the test sensitivity appears to be clinically suboptimal. This finding might be explained by insufficient time for the intravenous contrast material to wash out from benign lesions."

    Incidental Adrenal Lesions: Accuracy of Characterization with Contrast-enhanced Washout Multidetector CT—10-minute Delayed Imaging Protocol Revisited in a Large Patient Cohort
    Sangwaiya MJ et al.
    Radiology 2010; 256:504-510

  • "Ten minute delayed multidetector CT adrenal washout tests have reduced accuracy compared with results from prior studies; overall test accuracy at 40% threshold was 77.7% according to our test results."

    Incidental Adrenal Lesions: Accuracy of Characterization with Contrast-enhanced Washout Multidetector CT—10-minute Delayed Imaging Protocol Revisited in a Large Patient Cohort
    Sangwaiya MJ et al.
    Radiology 2010; 256:504-510

  • "The 10-minute delayed adrenal enhancement washout test has reduced sensitivity for the characterization of adrenal adenomas compared with results from prior studies."

     

    Incidental Adrenal Lesions: Accuracy of Characterization with Contrast-enhanced Washout Multidetector CT—10-minute Delayed Imaging Protocol Revisited in a Large Patient Cohort
    Sangwaiya MJ et al.
    Radiology 2010; 256:504-510

     

  • "The high diagnostic accuracy leads to a decrease in the number of patients with an indeterminate adrenal mass, which requires the other diagnostic methods including MR imaging, radionuclide imaging, and adrenal biopsy."

    Distinguishing Adrenal Adenomas from Nonadenomas: Combined Use of Diagnostic Parameters of Unenhanced and Short 5-minute Dynamic Enhanced CT Protocol
    Kamiyama T et al
    Radiology 2009; 250:474-481

  • Adrenal: Adrenal Adenoma: CT Criteria
    - Attenuation of less than or equal to 10HU on unenhanced CT
    - Absolute contrast washout of greater than or equal to 52 HU at 10 minutes or 60% at 15 minutes (100 ml injection of Omnipaque-350 at 3ml/sec)
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