Search

Objective: To investigate the utility of voxel histogram analysis (HA) for differentiating hyperdense renal cysts from small solid masses on unenhanced CT scans., Methods: A retrospective analysis of 99 hyperdense cystic lesions and 28 solid malignant lesions was conducted using a radiological database (from 2015 to 2021) and a pathological database (from 2010 to 2020). The study investigated the distribution of voxel attenuation values using percentiles to establish reliable criteria for differentiation after drawing a region of interest (ROI) in the centre of the lesions. The standard of reference was a histopathological diagnosis for malignant masses and contrast-enhanced CT or MRI for cysts., Results: HA provided higher diagnostic accuracy than the conventional mean attenuation value of 70 Hounsfield Units (HU). For the 75th and 90th percentiles ± 1 standard deviation, accuracies of 77.2% (95% confidence interval 68.9%-84.2%) for the 75th and 68.5% (59.7%-76.4%) for the 90th were found, versus 37.0% (28.6%-46.0%) for the 70 HU threshold criterion. A Gaussian distribution of voxel attenuation values was observed in 88.9% of the lesions, suggesting that it is feasible to calculate these parameters from a single measurement., Conclusion: The study underscores the potential of HA as a valuable tool for characterizing hyperdense cysts on unenhanced CT by using the same ROI for measuring lesion attenuation. HA could offer additional value beyond the 70 HU criterion and possibly influence clinical decisions. Multi-institutional studies are necessary for external validation to confirm its generalizability and more extensive applicability., Advances in Knowledge: (1) A single measurement on unenhanced CT images, using mean attenuation and standard deviation, accurately reflects the voxel distribution of both cystic and solid masses, allowing for the application of histogram analysis. (2) The 75th percentile threshold of 65 HU or higher could potentially increase sensitivity in diagnosing hyperdense cysts, compared to the 70 HU mean attenuation threshold, without compromising specificity., (© The Author(s) 2024. Published by Oxford University Press on behalf of the British Institute of Radiology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

We correlated contrast-enhanced cross-sectional imaging and outcomes to assess the reproducibility of ultrasonographic criteria for renal minimally complex (MC) cysts. From 2003 to 2015, 143 cysts were described as complex or MC by ultrasound (US). After exclusions, 98 US studies were retrospectively evaluated and compared with computed tomography (CT)/magnetic resonance imaging (MRI). At sonography, 51 were MC cysts and 47 were complexes according to two independent observers. Inter-observer agreement for US was 0.704 and 0.745 for CT/MRI. Of 51 cysts classified as MC by US, 38 were Bosniak I/II and 6 were Bosniak IIF by CT/MRI. In 7, there were no cross-sectional images; however, they were stable for at least 2 y. Of 47 complex cysts, 9 were Bosniak II, 22 Bosniak IIF, 8 Bosniak III and 8 Bosniak IV. No Bosniak III/IV cysts by CT/MRI were classified as MC by US. Our results indicate that US offers reproducible criteria for MC cysts and may be used alone for these lesions., (Copyright © 2017 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)

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.