Bosniak Calculator

Bosniak Calculator assigns Bosniak grades for cystic renal masses using magnetic resonance imaging (MRI) according to the Bosniak v.2019 classification to assess risk of malignancy.

Key Features:

• Integration with Bosniak v.2019: Incorporates the Bosniak v.2019 MRI-inclusive classification and its defined imaging terms to align MRI interpretation with the updated framework.
• Unenhanced MRI criteria: Applies classification criteria based on appearance on unenhanced MRI scans.
• T2-weighted signal criterion: Classifies homogeneous masses that are markedly hyperintense on T2-weighted imaging, similar to cerebrospinal fluid, as Bosniak II.
• Fat-suppressed T1-weighted threshold: Classifies homogeneous masses that are markedly hyperintense on fat-suppressed T1-weighted imaging (≈≥2.5× adjacent renal parenchyma) as Bosniak II.
• MRI indications where CT is limited: Emphasizes evaluation by MRI for masses with abundant thick or nodular calcifications, homogeneous hyperattenuating nonenhancing masses ≥3 cm, and heterogeneous nonenhancing masses.
• Technical efficacy: Supports technical efficacy at stage 3 for clinical application.

Scientific Applications:

• Bosniak grading of cystic renal masses: Assigns Bosniak categories to cystic renal lesions based on MRI findings.
• Malignancy risk stratification: Informs assessment of malignancy risk in cystic renal masses through Bosniak category allocation.
• MRI-based evaluation when CT is limited: Provides MRI-focused assessment for lesions with calcifications, hyperattenuating nonenhancing features ≥3 cm, or heterogeneous nonenhancing appearance.
• Interobserver agreement and specificity: Uses defined imaging terms and signal thresholds to improve interobserver agreement and specificity for malignancy detection.

Methodology:

Applies Bosniak v.2019 MRI-based classification rules to unenhanced MRI findings, using T2-weighted and fat-suppressed T1-weighted signal criteria (including a ≈≥2.5× parenchyma threshold and size-based considerations such as ≥3 cm) to assign Bosniak categories.