Bosniak classification version 2019: a prospective comparison of CT and MRI.

OBJECTIVE: To assess the diagnostic accuracy and agreement of CT and MRI in terms of the Bosniak classification version 2019 (BCv2019). MATERIALS AND METHODS: A prospective multi-institutional study enrolled 63 patients with 67 complicated cystic renal masses (CRMs) discovered during ultrasound examination. All patients underwent CT and MRI scans and histopathology. Three radiologists independently assessed CRMs using BCv2019 and assigned Bosniak class to each CRM using CT and MRI. The final analysis included 60 histopathologically confirmed CRMs (41 were malignant and 19 were benign). RESULTS: Discordance between CT and MRI findings was noticed in 50% (30/60) CRMs when data were analyzed in terms of the Bosniak classes. Of these, 16 (53.3%) were malignant. Based on consensus reviewing, there was no difference in the sensitivity, specificity, and accuracy of the BCv2019 with MRI and BCv2019 with CT (87.8%; 95% CI = 73.8-95.9% versus 75.6%; 95% CI = 59.7-87.6%; p = 0.09, 84.2%; 95% CI = 60.4-96.6% versus 78.9%; 95% CI = 54.4-93.9%; p = 0.5, and 86.7%; 95% CI = 64.0-86.6% versus 76.7%; 95% CI = 75.4-94.1%; p = 0.1, respectively). The number and thickness of septa and the presence of enhanced nodules accounted for the majority of variations in Bosniak classes between CT and MRI. The inter-reader agreement (IRA) was substantial for determining the Bosniak class in CT and MRI (k = 0.66; 95% CI = 0.54-0.76, k = 0.62; 95% CI = 0.50-0.73, respectively). The inter-modality agreement of the BCv219 between CT and MRI was moderate (κ = 0.58). CONCLUSION: In terms of BCv2019, CT and MRI are comparable in the classification of CRMs with no significant difference in diagnostic accuracy and reliability. KEY POINTS: • There is no significant difference in the sensitivity, specificity, and accuracy of the BCv2019 with MRI and BCv2019 with CT. • The number of septa and their thickness and the presence of enhanced nodules accounted for the majority of variations in Bosniak classes between CT and MRI. • The inter-reader agreement was substantial for determining the Bosniak class in CT and MRI and the inter-modality agreement of the BCv219 between CT and MRI was moderate.

The validity and reproducibility of the thyroid imaging reporting and data system (TI-RADS) in categorization of thyroid nodules: Multicentre prospective study.

PURPOSE: To assess diagnostic validity and reproducibility of Thyroid Imaging Reporting and Data System (TI-RADS) for interpretation of thyroid nodules by thyroid ultrasonography (US). METHOD: A prospective multicentre study initially included 557 patients with clinically suspected thyroid nodules. After exclusion, a final cohort of 380 patients with 948 thyroid nodules detected by US were enrolled. Based on American College of Radiology (ACR) TI-RADS, three radiologists analysed all US examinations independently and assigned a TI-RADS category to each thyroid nodule. The final diagnosis was based on cytology which was used as reference standard for calculating diagnostic performance of TI-RADS for predicting malignant thyroid nodules. The Fleiss and weighted kappa (κ) statistics were applied to assess inter-observer agreement of morphological features and TI-RADS scoring results for thyroid nodules. Additionally, we made a simple screening among referring clinicians to assess the clinical response to application of TI-RADS. RESULTS: A total of 948 thyroid nodules were evaluated; 136 (14.3%) were malignant, and 812 (85.7%) were benign. The papillary carcinoma was the most common malignant thyroid nodules (81.6%). The best cut-off value for predicting malignant thyroid nodules was > TR3. On a lesion-based analysis, the TI-RADS had a sensitivity, specificity, and an accuracy of 98.3%, 90.9%, and 92.1%, respectively when regarding those thyroid nodules classified as > TR3 for predicting malignancy. The inter-observer agreement of the TI-RADS category was good (κ = 0.636). Ninety percent of referring clinicians accept TI-RADS. CONCLUSIONS: TI-RADS improves diagnostic performance of US for predicting malignant thyroid nodules with high validity and high reproducibility.

The utility of diffusion-weighted imaging in improving the sensitivity of LI-RADS classification of small hepatic observations suspected of malignancy.

PURPOSE: We investigated the added value of diffusion-weighted imaging (DWI)/apparent diffusion coefficient (ADC) in the categorization of small hepatic observation (≤ 20 mm) detected in patients with chronic liver disease in reference to LI-RADS (liver imaging reporting and data system) classification system. METHODS: We prospectively evaluated 165 patients with chronic liver disease with small hepatic observations (≤ 20 mm) which were previously categorized as LI-RADS grade 3-5 on dynamic contrast-enhanced CT (DCE-CT). All patients were submitted to a functional MRI including DCE and DWI. Using LI-RADS v2017, two radiologists independently evaluated the observations and assigned a LI-RADS category to each observation using DCE-MRI alone and combined DCE-MRI and DWI/ADC. In the combined technique, the radiologists assigned a LI-RADS category based on a modified LI-RADS criteria in which restricted diffusion on DWI was considered a major feature of HCC. We evaluated the inter-reader agreement with Kappa statistics and compared the diagnostic performance of the LI-RADS with two imaging techniques by Fisher's exact test using histopathology as the reference standard. RESULTS: Combined technique in LI-RADS yielded better sensitivities (reader 1, 97% [65/67]; reader 2, 95.5% [64/67]) for HCC diagnosis than DCE-MRI alone (reader 1, 80.6% [54/67], p = 0.005; reader 2, 83.6% [56/67], p = 0.04). The specificities were insignificantly lower in combined technique (reader 1, 88.4% [107/121]; reader 2, 77.7% [94/121]) than in DCE-MRI alone (reader 1, 90.9% [110/121], p = 0.67; reader 2, 79.3% [96/121], p = 0.88). The inter-reader agreement of the LI-RADS scores between combined technique and DCE-MRI was good (κ = 0.765). CONCLUSION: The use of DWI/ADC as an additional major criterion, improved the sensitivity of LI-RADS in the diagnosis of HCC while keeping high specificity.