Bosniak Classification of Cystic Renal Masses Version 2019: Comparison of Categorization Using CT and MRI
- 1 February 2021
- journal article
- research article
- Published by American Roentgen Ray Society in American Journal of Roentgenology
- Vol. 216 (2), 412-420
- https://doi.org/10.2214/ajr.20.23656
Abstract
Background: Bosniak Classification, version 2019 recently proposed refinements for cystic renal mass characterization and now formally incorporates MRI, which may improve concordance with CT. Purpose: To compare concordance of CT and MRI in evaluation of cystic renal masses using Bosniak Classification, version 2019. Materials and Methods: In this IRB-approved and HIPAA compliant study, three abdominal radiologists (R1-R3) retrospectively reviewed 68 consecutive cystic renal masses from 45 patients assessed with both CT and MR renal mass protocols within a year between 2005-2019. CT and MRI were reviewed independently and in separate sessions, using both the original and version 2019 Bosniak Classification systems. Results: Using Bosniak Classification, version 2019, cystic renal masses were classified into 12 category I, 19 category II, 13 category IIF, 4 category III, and 20 category IV by CT and 8 category I, 15 category II, 23 category IIF, 9 category III, and 13 category IV by MRI. Among individual features, MRI depicted more septa (p<0.001, p=0.046, p=0.005 for R1-R3; McNemar's test) for all radiologists, though both CT and MRI showed a similar number of protrusions (p=0.823, 1.0, 0.302) and maximal septa/wall thickness (p=1.0, 1.0, 0.145). Of discordant cases with version 2019, MRI led to the higher category in 12 masses. Reason for upgrade was most commonly due to protrusions identified only on MRI (n=4), increased number of septa (n=3), and a new category of heterogeneously T1-hyperintense (n=3). Neither modality was more likely to lead to a category change for both version 2019 (p=0.502; McNemar's test) and the original Bosniak classification system (p=0.823). Overall inter-rater agreement was substantial for both CT (κ=0.745) and MRI (κ=0.655) using version 2019 and was slightly higher than that of the original system (CT κ=0.707; MRI κ=0.623). Conclusion: CT and MRI were concordant in the majority of cases using Bosniak Classification, version 2019 and category changes by modality were not statistically significant. Inter-rater agreements were substantial for both CT and MRI. Clinical Impact: Bosniak Classification, version 2019 applied to cystic renal masses has substantial inter-rater agreement and does not lead to systematic category upgrades with either CT or MRI.Keywords
This publication has 27 references indexed in Scilit:
- Diffusion-weighted magnetic resonance imaging in evaluation of primary solid and cystic renal masses using the Bosniak classificationEuropean Journal of Radiology, 2012
- The Bosniak Renal Cyst Classification: 25 Years LaterRadiology, 2012
- Category Migration of Renal Cystic Masses with Use of Gadolinium-Enhanced Magnetic Resonance ImagingKorean Journal of Urology, 2012
- Lower Limits of Detection Using Magnetic Resonance Imaging for Solid Components in Cystic Renal NeoplasmsUrology, 2008
- Follow-Up CT of Moderately Complex Cystic Lesions of the Kidney (Bosniak Category IIF)American Journal of Roentgenology, 2003
- Complex renal cysts: findings on MR imaging.American Journal of Roentgenology, 1999
- Diagnosis and management of patients with complicated cystic lesions of the kidney.American Journal of Roentgenology, 1997
- The Use of the Bosniak Classification System for Renal Cysts and Cystic TumorsJournal of Urology, 1997
- Letter to the editorAcademic Radiology, 1996
- Cystic renal masses: A reevaluation of the usefulness of the Bosniak classification systemAcademic Radiology, 1996