Our daily experience in a COVID hospital has allowed us to learn about this disease in many of its changing and unusual aspects. Some of these uncommon manifestations, however, appeared more frequently than others, giving shape to a multifaceted COVID-19 disease. This pictorial review has the aim to describe the radiological aspects of atypical presentations and of some complications of COVID-19 disease in adults and children and provide a simple guide for radiologists to become familiar with the multiform aspects of this disease.

The increasing number of reports on the influence of wettability on oil recovery and waterflood performance recognizes wettability of porous surfaces within reservoir rocks as the key factor that affects the success of water flooding processes. Unfortunately, a conclusive and satisfactory understanding of all the factors affecting the wettability of the reservoir rocks is still elusive. This is mainly due to the complexity of the intrinsic properties affecting the rock surface and due to the lack of techniques with sufficient spatial resolution necessary to assess the wettability at the pore scale. Using both macro-and microscopic analytical techniques, an idealized flat surface of mineral composition representative for carbonate type formation, i.e., calcite (CaCO 3 ), is studied to provide a baseline for future investigation of the underlining mechanisms influencing reservoir wettability. The development of heterogeneities on different calcite planes when exposure to the atmosphere is responsible for the transition in the observed wettability behavior. This work fills the absence of a baseline for the wettability of calcite and provides a reference for future investigation in oil reservoirs.

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Introduction The objective of this study was to compare the frequency and entity, in computed tomography (CT) urography, of streak artefacts on the urinary tract generated by two contrast agents with a different iodine concentration and osmolarity. Methods Computed tomography scans including an excretory renal phase, performed on adult subjects in the period May–July 2020, were retrospectively evaluated in consensus by three expert radiologists, to detect any streak artefacts located in the urinary tract. Patients were administered either 1.6 mL/kg of Iodixanol 320 mgI/mL or 1.3 mL/kg of Iomeprol 400 mgI/mL. Results In total, 144 CT scans were analysed, subdivided into two groups administered either Iodixanol (71/144 (49.3%) patients) or Iomeprol (73/144 (50.7%) patients). In 41% cases, no beam hardening artefacts were found; among these, 12/59 (20.3%) patients had received Iodixanol and 47/59 (79.7%) Iomeprol. In the Iodixanol group, the mean contrast density on the renal pelvis was 2565.6 HU and streak artefacts occurred in 59/71 cases (83.1%); in 33/59 (55.9%) cases, the artefacts were marked, and in 26/59 (44.1%) minimal. In the Iomeprol group, the mean contrast density on the renal pelvis was 1666 HU and streak artefacts occurred in 26/73 cases (35.6%); in 7/26 (27%) cases, the artefacts were marked and in 19/26 (73%) minimal. Conclusion The study data demonstrate a significant difference in the attenuation values of iodine urine in the excretory system between the Iodixanol and Iomeprol group. Iodixanol induced a higher frequency and burden of artefacts, compared to Iomeprol.

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