Background Pancreatic adenocarcinoma is a highly lethal disease even in initially resectable patients. Functional imaging procedures such as diffusion-weighted imaging (DWI) and computed tomography (CT)-perfusion might facilitate preoperative prediction of factors influencing prognosis in patients with pancreatic adenocarcinoma. Purpose To evaluate CT-perfusion and DWI quantitative parameters of pancreatic adenocarcinoma and to assess their correlation with clinicopathological features. Material and Methods Forty-four patients with histopathologically proven pancreatic adenocarcinoma underwent CT-perfusion and DWI for estimating blood volume (BV), blood perfusion (BF), mean transit time (MTT), time to peak (TTP), and apparent diffusion coefficient (ADC) values. The statistical analysis was performed using Wilcoxon matched-pairs test, t-test for independent samples, Spearman’s rank correlation coefficient (rs), and receiver operating characteristic analysis. Results The mean CT-perfusion parameters and ADCs were significantly different in pancreatic adenocarcinoma versus healthy parenchyma. BV (2.66 ± 0.98 mL/100g), BF (17.45 ± 4.06 mL/min/100g), and ADCs (0.91 ± 0.15 × 10−3mm/s2) in high-grade tumors were significantly lower in comparison to low-grade tumors (BV = 5.35 ± 1.36 mL/100g, BF = 28.51 ± 7.73 mL/min/100g, ADC = 1.07 ± 0.21 × 10−3mm/s2). For prediction of high-grade tumors, the sensitivity and specificity were 79.2% and 82.4% for BF and 87.5% and 88.2% for BV, respectively. A significant negative correlation was found between BV and tumor size (rs = −0.445, P = 0.029), MTT and tumor size (rs = −0.330, P = 0.043), BV and M-stage (rs = −0.286, P = 0.049), and ADC and M-stage (rs = −0.274, P = 0.038). Moreover, BF and BV values were significantly associated with ADCs. Conclusion CT-perfusion parameters and ADC values could improve preoperative assessment of pancreatic adenocarcinoma with possibility of tumor grade prediction.

Background Intrahepatic mass-forming cholangiocellular carcinoma (IMC) is the second most common primary liver tumor. The differentiation between IMC and solitary hypovascular liver metastases (SHLM) represents a diagnostic challenge due to many overlapping magnetic resonance imaging (MRI) features. Purpose To determine the value of diffusion-weighted imaging (DWI) in addition to conventional MRI for the distinction between intrahepatic mass-forming cholangiocarcinoma and solitary hypovascular liver metastases. Material and Methods Fifty-three patients with pathologically proven IMC (n = 31) and SHLM (n = 22) who had undergone MRI and DWI before surgery or percutaneous biopsy were enrolled in this study. The following MRI features were analyzed: the size and shape of the lesion, presence of capsular retraction and segmental biliary dilatation, T2-weighted (T2W) signal intensity, the presence of target sign on DWI and enhancement pattern. Apparent diffusion coefficient (ADC) values were calculated for each lesion ( b = 800 s/mm). Univariate and multivariate logistic regression analyses were used to identify significant differentiating features between IMCs and SHLMs. Results Univariate analysis revealed that following parameters favor diagnosis of IMCs over SHLMs: lobulating shape, heterogeneous T2W signal intensity, capsular retraction, segmental biliary dilatation, target sign on DWI and rim-like enhancement on arterial phase followed by progressive enhancement in delayed phases. ADC values measured in the periphery of the lesion were significantly lower in IMCs in comparison to SHLMs. Multivariate analysis revealed that target sign on DWI was the most significant predictor of IMCs. Conclusion Qualitative DWI analysis with target sign significantly improves diagnostic accuracy for differentiation among IMC and SHLM lesions.

Background The utility of intravoxel incoherent motion (IVIM) related parameters in differentiation of hypovascular liver lesions is still unknown. Purpose The purpose of this study was to evaluate the value of IVIM related parameters in comparison to apparent diffusion coefficient (ADC) for differentiation among intrahepatic mass-forming cholangiocarcinoma (IMC), and hypovascular liver metastases (HLM). Methods Seventy-four prospectively enrolled patients (21 IMC, and 53 HLM) underwent 1.5T magnetic resonance examination with IVIM diffusion-weighted imaging using seven b values (0–800 s/mm2). Two independent readers performed quantitative analysis of IVIM-related parameters and ADC. Interobserver reliability was tested using a intraclass correlation coefficient. ADC, true diffusion coefficient (D), perfusion-related diffusion coefficient (D*), and perfusion fraction (ƒ) were compared among the lesions using Kruskal-Wallis H test. The diagnostic accuracy of each parameter was assessed by receiver operating characteristic (ROC) curve analysis. Results The interobserver agreement was good for ADC (0.802), and excellent for D, D*, and ƒ (0.911, 0.927, and 0.942, respectively). ADC, and D values were significantly different among IMC and HLM (both p < 0.05), while there was no significant difference among these lesions for ƒ and D* (p = 0.101, and p = 0.612, respectively). ROC analysis showed higher diagnostic performance of D in comparison to ADC (AUC = 0.879 vs 0.821). Conclusion IVIM-derived parameters in particular D, in addition to ADC, could help in differentiation between most common hypovascular malignant liver lesions, intrahepatic mass—forming cholangiocarcinoma and hypovascular liver metastases.

Interstitial pneumonia is the main manifestation of the COVID-19 disease. The aim of this paper is to present the spectrum of typical radiological findings (CT - computed tomography, and radiographic) in COVID-19 pneumonia, the different CT examination techniques, the types and evolution of inflammatory lesions in the lungs, the criteria for assessing the probability of COVID-19 pneumonia in comparison to other types of interstitial pneumonia, and the scoring systems for determining the extent of COVID-19 pneumonia, based on CT findings and radiography. The standard CT examination protocol is a native CT examination of the chest, and, due to high sensitivity of low-dose CT protocols for detecting lung lesions, this imaging technique has become widely used in radiological practice during the COVID-19 pandemic. Bilateral, multiple, round or confluent zones of ground-glass density, predominantly localized subpleurally, peripherally and posteriorly, usually most extensive in the lower lobes, represent a typical CT presentation of COVID-19 pneumonia. Consolidations may develop at a later stage. A chest X-ray shows homogeneously reduced transparency in the lateral pulmonary fields, circular and irregular cloudlike shadows, and confluent patchy shadows, usually most extensive basally and laterally. RSNA and CO-RADS criteria are used to assess the probability of COVID-19 pneumonia, based on the criteria of a typical/atypical CT finding. Four stages of COVID-19 pneumonia have been defined, based on the dynamics of inflammatory lung lesion presentation: early, progressive, the phase of consolidation and the phase of organization. To assess the extent and severity of pneumonia, various scoring systems have been proposed, the most widely accepted one being the CT severity scoring system, based on visual semiquantitative assessment of the percentage of lung parenchyma inflammation lesions involvement of each of the five lobes, on a scale of 1 (<5%) to 5 (>75%), whereby the maximum score can be 25.