Objective: The aim of this study was to investigate the clinical and computed tomography (CT) features associated with severe and critical coronavirus disease 2019 pneumonia. Materials and Methods: Eighty-three patients with COVID-19 pneumonia including 25 severe/critical cases and 58 ordinary cases were enrolled. The chest CT images and clinical data of them were reviewed and compared. The risk factors associated with disease severity were analyzed. Results: Compared with the ordinary patients, the severe/critical patients had older ages, higher incidence of comorbidities, cough, expectoration, chest pain, and dyspnea. The incidences of consolidation, linear opacities, crazy-paving pattern, and bronchial wall thickening in severe/critical patients were significantly higher than those of the ordinary patients. Besides, severe/critical patients showed higher incidences of lymph node enlargement, pericardial effusion, and pleural effusion than the ordinary patients. The CT scores of severe/critical patients were significantly higher than those of the ordinary patients (P < 0.001). Receiver operating characteristic curve showed that the sensitivity and specificity of CT score were 80.0% and 82.8%, respectively, for the discrimination of the 2 types. The clinical factors of age older than 50 years, comorbidities, dyspnea, chest pain, cough, expectoration, decreased lymphocytes, and increased inflammation indicators were risk factors for severe/critical COVID-19 pneumonia. Computed tomography findings of consolidation, linear opacities, crazy-paving pattern, bronchial wall thickening, high CT scores, and extrapulmonary lesions were features of severe/critical COVID-19 pneumonia. Conclusions: There are significant differences in clinical symptoms, laboratory examinations, and CT manifestations between the ordinary patients and the severe/ critical patients. Many factors are related to the severity of the disease, which can help clinicians to judge the severity of the patient and evaluate the prognosis.

Objectives: The aim of this study was to investigate the chest computed tomography (CT) findings in patients with confirmed coronavirus disease 2019 and to evaluate its relationship with clinical features. Materials and Methods: Study sample consisted of 80 patients diagnosed as COVID-19 from January to February 2020. The chest CT images and clinical data were reviewed, and the relationship between them was analyzed. Results: Totally, 80 patients diagnosed with COVID-19 were included. With regards to the clinical manifestations, 58 (73%) of the 80 patients had cough, and 61 (76%) of the 80 patients had high temperature levels. The most frequent CT abnormalities observed were ground glass opacity (73/80 cases, 91%), consolidation (50/80 cases, 63%), and interlobular septal thickening (47/80, 59%). Most of the lesions were multiple, with an average of 12 ± 6 lung segments involved. The most common involved lung segments were the dorsal segment of the right lower lobe (69/80, 86%), the posterior basal segment of the right lower lobe (68/80, 85%), the lateral basal segment of the right lower lobe (64/80, 80%), the dorsal segment of the left lower lobe (61/80, 76%), and the posterior basal segment of the left lower lobe (65/80, 81%). The average pulmonary inflammation index value was (34% ± 20%) for all the patients. Correlation analysis showed that the pulmonary inflammation index value was significantly correlated with the values of lymphocyte count, monocyte count, C-reactive protein, procalcitonin, days from illness onset, and body temperature (P < 0.05). Conclusions: The common chest CT findings of COVID-19 are multiple ground glass opacity, consolidation, and interlobular septal thickening in both lungs, which are mostly distributed under the pleura. There are significant correlations between the degree of pulmonary inflammation and the main clinical symptoms and laboratory results. Computed tomography plays an important role in the diagnosis and evaluation of this emerging global health emergency.

Objectives To systematically analyze CT findings during the early and progressive stages of natural course of coronavirus disease 2019 and also to explore possible changes in pulmonary parenchymal abnormalities during these two stages. Methods We retrospectively reviewed the initial chest CT data of 62 confirmed coronavirus disease 2019 patients (34 men, 28 women; age range 20-91 years old) who did not receive any antiviral treatment between January 21 and February 4, 2020, in Chongqing, China. Patients were assigned to the early-stage group (onset of symptoms within 4 days) or progressive-stage group (onset of symptoms within 4-7 days) for analysis. CT characteristics and the distribution, size, and CT score of pulmonary parenchymal abnormalities were assessed. Results In our study, the major characteristic of coronavirus disease 2019 was ground-glass opacity (61.3%), followed by ground-glass opacity with consolidation (35.5%), rounded opacities (25.8%), a crazy-paving pattern (25.8%), and an air bronchogram (22.6%). No patient presented cavitation, a reticular pattern, or bronchial wall thickening. The CT scores of the progressive-stage group were significantly greater than those of the early-stage group (p = 0.004). Conclusions Multiple ground-glass opacities with consolidations in the periphery of the lungs were the primary CT characteristic of coronavirus disease 2019. CT score can be used to evaluate the severity of the disease. If these typical alterations are found, then the differential diagnosis of coronavirus disease 2019 must be considered. Key Points • Multiple GGOs with consolidations in the periphery of the lungs were the primary CT characteristic of COVID-19.• The halo sign may be a special CT feature in the early-stage COVID-19 patients.• Significantly increased CT score may indicate the aggravation of COVID-19 in the progressive stage.

Multimodal molecular imaging has shown promise as a complementary approach to thrombus detection. However, the simultaneous noninvasive detection and lysis of thrombi for cardiovascular diseases remain challenging. Herein, a perfluorohexane (PFH)-based biocompatible nanostructure was fabricated, namely, as-prepared Fe3O4-poly­(lactic-co-glycolic acid)-PFH-CREKA nanoparticles (NPs), which combine phase transition (PT) thrombolysis capabilities with properties conducive to multimodal imaging. This well-developed PT agent responded effectively to low-intensity focused ultrasound (LIFU) by triggering the vaporization of liquid PFH to achieve thrombolysis. The presence of the CREKA peptide, which binds to the fibrin of the thrombus, allows targeted imaging and efficacious thrombolysis. Then, we found that, compared with thrombolysis using a non-phase-transition agent, PT thrombolysis can produce a robust decrease in the thrombus burden regardless of the acoustic power density of LIFU. In particular, the reduced energy for LIFU-responsive PT during the lysis process guarantees the superior safety of PT thrombolysis. After injecting the NPs intravenously, we demonstrated that this lysis process can be monitored with ultrasound and photoacoustic imaging in vivo to evaluate its efficacy. Therefore, this nonpharmaceutical strategy departs from routine methods and reveals the potential use of PT thrombolysis as an effective and noninvasive alternative to current thrombolytic therapy.

Thrombotic disease is extremely harmful to human health, but early detection and treatment can help improve prognoses and reduce mortality. To date, few studies have used MR molecular imaging in the early detection of thrombi and in the dynamic monitoring of the thrombolytic efficiency. In this article, we construct Fe3O4-based poly(lactic-co-glycolic acid) (PLGA) nanoparticles to use in the detection of thrombi and in targeted thrombolysis using MRI monitoring. Cyclic arginine-glycine-aspartic peptide (cRGD) was grafted onto the chitosan (CS) surface to synthesize a CS-cRGD film using carbodiimide-mediated amide bond formation. A double emulsion solvent evaporation method (water in oil in water [W/O/W]) was used to construct Fe3O4-based PLGA nanoparticles carrying recombinant tissue plasminogen activator (rtPA) (Fe3O4-PLGA-rtPA/CS-cRGD). Fe3O4-PLGA, Fe3O4-PLGA-rtPA, and Fe3O4-PLGA-rtPA/CS nanoparticles were constructed using the same W/O/W method. The results showed that the Fe3O4-based nanoparticles were constructed successfully and have a regular shape, a relatively uniform size, a high carrier rate of Fe3O4 and encapsulation efficiency of rtPA, and a relatively high activity of released rtPA. Transmission electron microscope (TEM) images revealed that the iron oxide particles were relatively uniformly distributed in the nano-spherical shell. The Fe3O4-based nanoparticles could be imaged using a clinical MRI scanner, and there were no significant differences in the transverse relaxation rate (R2*) or in the signal-to-noise ratio (SNR) values between the Fe3O4-based nanoparticles and an Fe3O4 solution with the same concentration of Fe3O4. In vitro and in vivo experiments confirmed that the Fe3O4-PLGA-rtPA/CS-cRGD nanoparticles specifically accumulated on the edge of the thrombus and that they had a significant effect on the thrombolysis compared with the Fe3O4-PLGA, Fe3O4-PLGA-rtPA, and Fe3O4-PLGA-rtPA/CS nanoparticles and with free rtPA solution. These results suggest the potential of the Fe3O4-PLGA-rtPA/CS-cRGD nanoparticles as a dual-function tool in the early detection of a thrombus and in the dynamic monitoring of the thrombolytic efficiency using MRI.