Background The multi-detector computed tomography (MDCT) and tissue biopsy are the gold standards for the evaluation of lung malignancies. However, there is a wide range of pulmonary indeterminate lesions that could mimic lung cancer. Furthermore, the diagnosis of malignancy could be challenging if the lesion is small and early presenting by a part-solid or ground-glass nodule or if surrounded by parenchymal lung reaction with consolidation and atelectasis. The previous literature focused on the role of diffusion-weighted image–magnetic resonance imaging (DWI) and the apparent diffusion coefficient (ADC) mapping in the evaluation of lung malignancy. A novel quantitative T2 assessment is provided and tested in this study. Aim of the work: To evaluate the accuracy of specific non-invasive quantitative magnetic resonance imaging (MRI) parameters in the characterization of suspicious lung lesions and the discrimination between the malignant and benign nature. They included the lesion-to-spinal cord signal intensity ratio in T2-WI and DWI as well as the mean and minimum apparent diffusion coefficient (ADC) values. This is performed using a prospective pathologic correlated study with receiver-operating characteristics (ROC) analysis and comparison with positron emission tomography (PET-CT) accuracy results. Results This study was prospectively performed during the period between June/2021 and June/2022. It was conducted on 43 suspicious lung lesions detected by MDCT. MRI and PET/CT examinations were performed for all patients, and the results were compared to the final diagnosis obtained after biopsy and pathological assessment, using the statistical tests of significance and P-value. Cutoff values were automatically calculated, and then, accuracy tests and ROC analyses were performed. Five expert radiologists and a single consulting pulmonologist participated in this study. The inter-rater reliability ranges between good and excellent with the intra-class correlation coefficient (ICC) ranging between 0.85 and 0.94. In T2-WI: The lesion-to-spinal cord signal intensity ratio was higher in the malignant group (1.35 ± 0.29) than in the benign group (0.88 ± 0.40), (P < 0.001). At the estimated cutoff value (> 1), the sensitivity was 96.43%, the specificity was 80.00%, and AUC = 0.86. In b500-DWI: The lesion-to-spinal cord signal intensity ratio was higher in the malignant group (0.70–1.35) than in the benign group (0.20–0.70) (P < 0.001). At the estimated cutoff value (> 0.7), the sensitivity was 71.43%, the specificity was 86.67%, and AUC = 0.86. The mean and minimum ADC values were lower in the malignant group (0.6–1.3 and 0.3–1.1 × 10–3 mm2/s) than the benign group (1–1.6 and 0.7–1.4 × 10–3 mm2/s), (P < 0.01 and < 0.001, respectively). At their estimated cutoff values (≤ 1.2 and ≤ 0.9 × 10–3 mm2/s, respectively), the sensitivity was (71.4 and 85.7%), specificity was (83.3 and 66.7%), respectively, and AUC = 0.77 for both. PET/CT had 96.4% sensitivity, 92.3% specificity, and AUC = 0.94. Conclusions PET-CT remains the most specific and sensitive tool for the differentiation between benign and malignant lesions. The lesion-to-cord signal intensity ratios in T2WI and DWI-MRI and to a minor extent the mean and minimum ADC values are also considered good parameters for this differentiation based on their accurate statistical results, particularly if PET/CT was not available or feasible. The study added to the previous literature a novel quantitative T2WI assessment which proved a high sensitivity equal to PET/CT with a lower but a good specificity. The availability, expertise, time factor, and patients' tolerance remain challenging factors for MRI.

Background Several clinical studies tested the efficacy of the different COVID-19 vaccinations while very few radiological researches targeted this issue before. Aim of the work To verify the additive role of lung CT-Volumetry in testing the efficacy of three widely distributed COVID-19 vaccinations; namely the "Sinopharm", "Oxford-AstraZeneca", and "Pfizer-BioNTech" vaccinations, with comparative analysis of variance (ANOVA). Results This study was retrospectively conducted on 341 COVID-19 patients during the period between June/2021 and March/2022. Based on the immunization status, they were divided into four groups; group (A) included 156/341 (46%) patients who did not receive any vaccination (control group), group (B) included 92/341 (27%) patients who received "Sinopharm" vaccine, group (C) included 55/341 (16%) patients who received "Oxford-AstraZeneca" vaccine, group (D) included 38/341 (11%) patients who received "Pfizer-BioNTech" vaccine. Every group was subdivided based on the medical history into three groups; group (1) patients without comorbidities, group (2) patients with comorbidities, and group (3) immunocompromised patients. Automated CT volumetry was calculated for the pathological lung parenchyma. Five CT-severity scores were provided (score 0 = 0%, score 1 = 1–25%, score 2 = 25–50%, score 3 = 51–75%, and score 4 = 76–100%). Analysis of variance (ANOVA) including Tukey HSD testing was utilized in comparison to the non-immunized patients. The "Phizer-Biontech" vaccine succeeded to eliminate severity in patients without and with comorbidity, and also decreased severity in immunocompromised patients (from 79 to 17%). The "Oxford-AstraZeneca" vaccine and to a lesser extent "Sinopharm" vaccine also decreased the clinical severity in patients with comorbidities and immunocompromised patients (from 15 to 9% & 10% as well as from 79 to 20% & 50% respectively). Significant variance was proved regarding the use of "Sinopharm", "Oxford-AstraZeneca", and "Phizer-Biontech" vaccines in patients without comorbidities (f-ratio averaged 4.0282, 10.8049, and 8.4404 respectively, also p-value averaged 0.04632, 0.001268, and 0.004294). Significant variance was proved regarding the use of "Oxford-AstraZeneca", and "Phizer-Biontech" vaccines in patients with comorbidities and immunocompromised patients (f-ratio averaged 4.7521, and 4.1682 as well as 11.7811, and 15.6 respectively, also p-value averaged 0.03492, and 0.04857, as well as both 0.003177, and 0.0009394 respectively, all < 0.05). No significant variance was proved regarding the use of the "Sinopharm" vaccine. Conclusions In addition to the decline of clinical severity rates & CT severity scores, a significant variance was proved regarding the use of the "Sinopharm", "Oxford-AstraZeneca", and "Phizer-Biontech" vaccines in patients without comorbidities. Significant variance was also proved regarding the use of the "Oxford-AstraZeneca" and "Phizer-Biontech" vaccines in patients with comorbidities and immunocompromised patients. Despite that, no significant variance could be proved regarding the use of the "Sinopharm" vaccine in these patients, it decreases the percentage of clinical severity and CT severity scores.

Background Some COVID-19 patients with similar quantitative CT measurements had variable clinical presentation and outcome. The absence of reasonable clinical explanations, such as pre-existing comorbidities or vascular complications, adds to the confusion. The authors believed that neglecting the impact of certain severe morphologic features could be an alternative radiological explanation. This study aims to optimize the initial CT staging of COVID-19 and propose a new combined morphologic/volumetric CT severity index (CTSI) to solve this clinico-radiological mismatch. Results This multi-center study included two major steps. The first step of the study entailed a standardized combined morphologic/volumetric CT severity analyses to propose a new optimized CTSI. This was conducted retrospectively during the period from June till September 2020. It included 379 acutely symptomatic COVID-19 patients. They were clinically classified according to their oxygen saturation and respiratory therapeutic requirements into three groups: group A (mild 298/79%), group B (borderline severity 57/15%), and group C (severe/critical 24/6%). The morphologic and volumetric assessment of their HRCT was analyzed according to severity, by two consultant radiologists in consensus. A new 25 point-CTSI has been created, combining eight morphological CT patterns [M1:M8; 8 points] and four grades of volumetric scores [S1:S4; 17 points]. The addition of the M5 pattern (air bubble sign), M6 pattern (early fibrosis and architectural distortion), or M7 pattern (crazy-paving) proved to increase the clinical severity. The second step of the study entailed a standardized blinded/independent validation analysis for the proposed CTSI. This was prospectively conducted on other 132 patients during October 2020 and independently performed by other two consultant radiologists. Validation results reached 80.2% sensitivity, 91.8% specificity, AUROC-curve = 0.8356, and 90.9% accuracy. Conclusion A new optimized CTSI with accepted validation is proposed for initial staging of COVID-19 patients, using combined morphologic/volumetric assessment instead of the quantitative assessment alone. It could solve the clinico-radiological mismatch among patients with similar quantitative CT results and variable clinical presentation during the absence of pre-existing comorbidities or vascular complications.