Modified approach to the characterization of adrenal nodules using a standard abdominal magnetic resonance imaging protocol

António P. Matos, Richard C. Semelka, Vasco Herédia, Mamdoh Alobaidiy, Filipe Veloso Gomes, Miguel Ramalho

Research output: Research - peer-reviewArticle

Abstract

Objective: To describe a modified approach to the evaluation of adrenal nodules using a standard abdominal magnetic resonance imaging protocol. Materials and Methods: Our sample comprised 149 subjects (collectively presenting with 132 adenomas and 40 nonadenomas). The adrenal signal intensity index was calculated. Lesions were grouped by pattern of enhancement (PE), according to the phase during which the wash-in peaked: arterial phase (type 1 PE); portal venous phase (type 2 PE); and interstitial phase (type 3 PE). The relative and absolute wash-out values were calculated. To test for mean differences between adenomas and nonadenomas, Student’s t-tests were used. Receiver operating characteristic curve analysis was also performed. Results: The mean adrenal signal intensity index was significantly higher for the adenomas than for the nonadenomas (p < 0.0001). Chemical shift imaging showed a sensitivity and specificity of 94.4% and 100%, respectively, for differentiating adenomas from nonadenomas. Of the adenomas, 47.6%, 48.5%, and 3.9%, respectively, exhibited type 1, 2, and 3 PEs. For the mean wash-in proportions, significant differences were found among the enhancement patterns. The wash-out calculations revealed a trend toward better lesion differentiation for lesions exhibiting a type 1 PE, showing a sensitivity and specificity of 71.4% and 80.0%, respectively, when the absolute values were referenced, as well as for lesions exhibiting a type 2 PE, showing a sensitivity and specificity of 68.0% and 100%, respectively, when the relative values were referenced. The calculated probability of a lipid-poor lesion that exhibited a type 3 PE being a nonadenoma was > 99%. Conclusion: Subgrouping dynamic enhancement patterns yields high diagnostic accuracy in differentiating adenomas from nonadenomas.

Translated title of the contributionModified approach to the characterization of adrenal nodules using a standard abdominal magnetic resonance imaging protocol
LanguagePortuguese
Pages19-25
Number of pages7
JournalRadiologia Brasileira
Volume50
Issue number1
DOIs
StatePublished - Jan 1 2017

Fingerprint

Adenoma
Magnetic Resonance Imaging
Sensitivity and Specificity
ROC Curve
Students
Lipids

Keywords

  • Adenoma
  • Adrenal gland neoplasms
  • Contrast media
  • Image enhancement
  • Magnetic resonance imaging

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

Cite this

Abordagem modificada na caracterização de nódulos adrenais utilizando um protocolo padrão de ressonância magnética abdominal. / Matos, António P.; Semelka, Richard C.; Herédia, Vasco; Alobaidiy, Mamdoh; Gomes, Filipe Veloso; Ramalho, Miguel.

In: Radiologia Brasileira, Vol. 50, No. 1, 01.01.2017, p. 19-25.

Research output: Research - peer-reviewArticle

Matos, António P. ; Semelka, Richard C. ; Herédia, Vasco ; Alobaidiy, Mamdoh ; Gomes, Filipe Veloso ; Ramalho, Miguel. / Abordagem modificada na caracterização de nódulos adrenais utilizando um protocolo padrão de ressonância magnética abdominal. In: Radiologia Brasileira. 2017 ; Vol. 50, No. 1. pp. 19-25
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abstract = "Objective: To describe a modified approach to the evaluation of adrenal nodules using a standard abdominal magnetic resonance imaging protocol. Materials and Methods: Our sample comprised 149 subjects (collectively presenting with 132 adenomas and 40 nonadenomas). The adrenal signal intensity index was calculated. Lesions were grouped by pattern of enhancement (PE), according to the phase during which the wash-in peaked: arterial phase (type 1 PE); portal venous phase (type 2 PE); and interstitial phase (type 3 PE). The relative and absolute wash-out values were calculated. To test for mean differences between adenomas and nonadenomas, Student’s t-tests were used. Receiver operating characteristic curve analysis was also performed. Results: The mean adrenal signal intensity index was significantly higher for the adenomas than for the nonadenomas (p < 0.0001). Chemical shift imaging showed a sensitivity and specificity of 94.4% and 100%, respectively, for differentiating adenomas from nonadenomas. Of the adenomas, 47.6%, 48.5%, and 3.9%, respectively, exhibited type 1, 2, and 3 PEs. For the mean wash-in proportions, significant differences were found among the enhancement patterns. The wash-out calculations revealed a trend toward better lesion differentiation for lesions exhibiting a type 1 PE, showing a sensitivity and specificity of 71.4% and 80.0%, respectively, when the absolute values were referenced, as well as for lesions exhibiting a type 2 PE, showing a sensitivity and specificity of 68.0% and 100%, respectively, when the relative values were referenced. The calculated probability of a lipid-poor lesion that exhibited a type 3 PE being a nonadenoma was > 99%. Conclusion: Subgrouping dynamic enhancement patterns yields high diagnostic accuracy in differentiating adenomas from nonadenomas.",
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