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MRI evaluation of complex renal cysts using the Bosniak classification: a comparison to CT

Abdominal Radiology volume 41, pages 2011–2019 (2016)Cite this article

Abstract

Purpose

The purpose of this study was to compare the ability of magnetic resonance imaging (MRI) and computed tomography (CT) to discriminate between benign and malignant cystic renal lesions utilizing the Bosniak classification.

Materials and Methods

We retrospectively searched our Radiological Information System using renal/kidney cysts as entries. The search retrieved 2929 patients and 525 complex renal cysts. After exclusions, 42 complex cysts, from 37 patients, with CT and MRI, up to six months apart, were included. Surgery and pathology report and follow-up of at least 24 months were used as a standard of reference.

Results

The mean age of patients was 51.4 years, ranging from 11 to 82 years old. Twenty-nine lesions were classified as Bosniak I, II or II-F by CT and/or MRI and 13 as Bosniak III or IV, by one of the methods. The interobserver agreement for Bosniak classification for CT was 0.87 and 0.93 for MRI. Fifteen lesions had higher Bosniak categories on MRI, included six with change in management. Only two lesions had a higher category on CT, one with change in management. The frequency of malignancy for Bosniak III was 50 % (2/4) for CT and 20% for MRI (1/5), as Bosniak upgrades by MRI resulted in surgery for benign lesions. Both methods had 100 % frequency of malignancy for category 4.

Conclusion

MRI led to category migration and management change of complex renal cysts in a significant proportion of cases, likely due to its superior soft tissue and contrast resolution. The impact of MRI on detection and outcomes of malignant complex renal cysts still requires further investigation.

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Affiliations

  1. Radiology Division, Internal Medicine Department, Ribeirao Preto School of Medicine, University of Sao Paulo, São Paulo, Brazil

    Aila Menezes Ferreira & Plinio Prizon Kajiwara

  2. Department of Surgery, Urology Division, Ribeirao Preto School of Medicine, University of Sao Paulo, São Paulo, Brazil

    Rodolfo Borges Reis

  3. Department of Pathology, Ribeirao Preto School of Medicine, University of Sao Paulo, São Paulo, Brazil

    Gyl Eanes Barros Silva

  4. Radiology Division, Internal Medicine Department, Ribeirao Preto School of Medicine, University of Sao Paulo, Av Bandeirantes 3900, Campus Monte Alegre, Ribeirão Preto, 14048-900, Brazil

    Jorge Elias Jr & Valdair Francisco Muglia

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  1. Aila Menezes Ferreira
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  2. Rodolfo Borges Reis
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  3. Plinio Prizon Kajiwara
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  4. Gyl Eanes Barros Silva
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  5. Jorge Elias Jr
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  6. Valdair Francisco Muglia
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Correspondence to Valdair Francisco Muglia.

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All authors declare no conflict of interest.

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All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.

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Informed consent was waived by Institutional IRB.

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Ferreira, A.M., Reis, R.B., Kajiwara, P.P. et al. MRI evaluation of complex renal cysts using the Bosniak classification: a comparison to CT. Abdom Radiol 41, 2011–2019 (2016). https://doi.org/10.1007/s00261-016-0797-5

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  • DOI: https://doi.org/10.1007/s00261-016-0797-5

Keywords

  • Renal cysts
  • Kidney cysts
  • Bosniak classification
  • Computed tomography (CT)
  • Magnetic resonance imaging (MRI)