Nyquist sampling theorem and Bosniak classification, version 2019: effect of thin axial sections on categorization and agreement.

To determine if CT axial images reconstructed at current standard of care (SOC; 2.5-3 mm) or thin (≤ 1 mm) sections affect categorization and inter-rater agreement of cystic renal masses assessed with Bosniak classification, version 2019. In this retrospective single-center study, 3 abdominal radiologists reviewed 131 consecutive cystic renal masses from 100 patients performed with CT renal mass protocol from 2015 to 2021. Images were reviewed in two sessions: first with SOC and then the addition of thin sections. Individual and overall categorizations are reported, latter of which is based on majority opinion with 3-way discrepancies resolved by a fourth reader. Major categorization changes were defined as differences between classes I-II, IIF, or III-IV. Thin sections led to a statistically significant major category change with class II for all readers individually (p = 0.004-0.041; McNemar test), upgrading 10-17% of class II masses, most commonly to class IIF followed by III. Modal reason for upgrades was due to identification of additional septa followed by larger measurement of enhancing features. Masses categorized as class I, III, or IV on SOC sections were unaffected, as were identification of protrusions. Inter-rater agreements using weighted Cohen's kappa were 0.679 for SOC and 0.691 for thin sections (both substantial). Thin axial sections upgraded up to one in six class II masses to IIF or III through identification of additional septa or larger feature. Other classes, including III-IV, were unaffected. Inter-rater agreements were substantial regardless of section thickness. • Thin axial sections (≤ 1 mm) compared to standard of care sections (2.5-3 mm) led to identification of additional septa but did not affect identification of protrusions. • Thin axial sections (≤ 1 mm) compared to standard of care sections (2.5-3 mm) can upgrade a small proportion of cystic renal masses from class II to IIF or III when applying Bosniak classification, version 2019. • Inter-rater agreements were substantial regardless of section thickness.

Tse JR ，Shen L ，Shen J ，Yoon L ，Kamaya A ... -  《-》

Bosniak Classification of Cystic Renal Masses Version 2019: Comparison of Categorization Using CT and MRI.

Tse JR ，Shen J ，Shen L ，Yoon L ，Kamaya A ... -  《-》

Proportion of malignancy in Bosniak classification of cystic renal masses version 2019 (v2019) classes: systematic review and meta-analysis.

Determine the proportion of malignancy within Bosniak v2019 classes. MEDLINE and EMBASE were searched. Eligible studies contained patients with cystic renal masses undergoing CT or MRI renal protocol examinations with pathology confirmation, applying Bosniak v2019. Proportion of malignancy was estimated within Bosniak v2019 class. Risk of bias was assessed using QUADAS-2. We included 471 patients with 480 cystic renal masses. No class I malignant masses were observed. Pooled proportion of malignancy were class II, 12% (6/51, 95% CI 5-24%); class IIF, 46% (37/85, 95% CI 28-66%); class III, 79% (138/173, 95% CI 68-88%); and class IV, 84% (114/135, 95% CI 77-90%). Proportion of malignancy differed between Bosniak v2019 II-IV classes (p = 0.004). Four studies reported the proportion of malignancy by wall/septa feature. The pooled proportion of malignancy with 95% CI were class III thick smooth wall/septa, 77% (41/56, 95% CI 53-91%); class III obtuse protrusion ≤ 3 mm (irregularity), 83% (97/117, 95% CI 75-89%); and class IV nodule with acute angulation, 86% (50/58, 95% CI 75-93%) or obtuse angulation ≥ 4 mm, 83%, (64/77, 95% CI 73-90%). Subgroup analysis by wall/septa feature was limited by sample size; however, no differences were found comparing class III masses with irregularity to class IV masses (p = 0.74) or between class IV masses by acute versus obtuse angles (p = 0.62). Preliminary data suggest Bosniak v2019 class IIF masses have higher proportion of malignancy compared to the original classification, controlling for pathologic reference standard. There are no differences in proportion of malignancy comparing class III masses with irregularities to class IV masses with acute or obtuse nodules. • The proportion of malignancy in Bosniak v2019 class IIF cystic masses is 46% (37 malignant/85 total IIF masses, 95% confidence intervals (CI) 28-66%). • The proportion of malignancy in Bosniak v2019 class III cystic masses is 79% (138/173, 95% CI 68-88%) and in Bosniak v2019 class IV cystic masses is 84% (114/135, 95% CI 77-90%). • Class III cystic masses with irregularities had similar proportion of malignancy (83%, 97/117, 95% CI 75-89%) compared to Bosniak class IV masses (84%, 114/135, 95% CI 77-90%) overall (p = 0.74) with no difference within class IV masses by acute versus obtuse angulation (p = 0.62).

McGrath TA ，Bai X ，Kamaya A ，Park KJ ，Park MY ，Tse JR ，Wang H ，McInnes MDF ，Schieda N ... -  《-》

Outcomes of Bosniak Classification Version 2019 Class IIF Cystic Renal Masses at Imaging Surveillance.

Shen L ，Yoon L ，Chung BI ，Kamaya A ，Tse JR ... -  《-》

Bosniak Classification version 2019: validation and comparison to original classification in pathologically confirmed cystic masses.

To evaluate Bosniak Classification v2019 definitions in pathologically confirmed cystic renal masses. Seventy-three cystic (≤ 25% solid) masses with histological confirmation (57 malignant, 16 benign) imaged by CT (N = 28) or CT+MRI (N = 56) between 2009 and 2019 were independently evaluated by three blinded radiologists using Bosniak v2019 and original classifications. Discrepancies were resolved by consensus with a fourth blinded radiologist. Overall class and v2019 features were compared to pathology. Inter-observer agreement was slightly improved comparing v2019 to Original Bosniak Classification (kappa = 0.26-0.47 versus 0.24-0.34 respectively). v2019 proportion of IIF and III masses (20.5% [15/73, 95% confidence interval (CI) 12.0-31.6%], 38.6% [28/73, 95% CI 27.2-50.5%]) differed from the original classification (6.8% [5/73, 95% CI 2.3-15.3%], 61.6% [45/73, 95% CI 49.5-72.8%]) with overlapping proportion of malignancy in each class. Mean septa number (7 ± 4 [range 1-10]) was not associated with malignancy (p = 0.89). Mean wall and septa thicknesses were 3 ± 3 (1-14) and 3 ± 2 (1-10) mm and higher in malignancies (p = 0.03 and 0.20 respectively). Areas under the receiver-operator-characteristic curve for wall and septa thickness were 0.66 (95% CI 0.54-0.79) and 0.61 (95% CI 0.45-0.78) with an optimal cut point of ≥ 3 mm (sensitivity 33.3%, specificity 86.7% and sensitivity 53%, specificity 73% respectively). Proportion of malignancy occurring in masses with the v2019 features "irregularity" (76.9% [10/13], 95% CI 46.2-94.9%) and "nodule" (89.7% [26/29], 95% CI 72.7-97.8%) overlapped. Angle of "nodule" (p = 0.27) was not associated with malignancy. Bosniak v2019 definitions for wall/septa thickness and protrusions are associated with malignancy. Overall, Bosniak v2019 categorizes a higher proportion of malignant masses in Class IIF with slight improvement in inter-observer agreement. • Considering Bosniak v2019 Class IIF cystic masses with many (≥ 4) smooth and thin septa, there was no association between the number of septa and malignancy (p = 0.89) in this study. • Increased cyst wall and septa thickness are associated with malignancy and a lower threshold of ≥ 3 mm maximized overall diagnostic accuracy compared to ≥ 4 mm threshold proposed for Bosniak v2019 Class 3. • An overlapping proportion of malignant masses is noted in Bosniak v2019 Class 3 masses with "irregularity" (76.9% [10/13], 95% CI 46.2-94.9%) compared to Bosniak v2019 Class 4 masses with "nodule" (89.7% [26/29], 95% CI 72.7-97.8%).

Yan JH ，Chan J ，Osman H ，Munir J ，Alrasheed S ，Flood TA ，Schieda N ... -  《-》