Although paragangliomas can occur in a variety of anatomic locations, the majority are seen in relatively predictable regions of the body. Extraadrenal paragangliomas have nearly identical imaging features, including a homogeneous or heterogeneous hyperenhancing soft-tissue mass at CT, multiple areas of signal void interspersed with hyperintense foci (salt-and-pepper appearance) within tumor mass at MRI, and an intense tumor blush with enlarged feeding arteries at angiography.

ObjectiveTo describe CT and clinical findings of pulmonary artery intimal sarcoma (PAIS) compared with those of pulmonary thromboembolism (PTE), to investigate MRI and positron emission tomography (PET)-CT findings of PAIS, and to evaluate the effect of delayed diagnosis of PAIS on survival outcomes.Materials and MethodsTwenty-six patients with PAIS were retrospectively identified and matched for sex, with patients with PTE at a ratio of 1:2. CT and clinical findings of the two groups were compared using Student's t test or chi-square test. The effect of delayed diagnosis on survival was investigated using Kaplan-Meier analysis.ResultsThe most common tumor pattern in PAIS was tumoral impaction. Heterogeneous attenuation, wall eclipse signs, intratumoral vessels, acute interphase angles, single location, presence of lung ischemia, and central location were significantly more common in PAIS than in PTE (all p < 0.01). Levels of D-dimers and brain natriuretic peptide were lower in PAIS than in PTE (p < 0.05). In three patients of PAIS, long inversion time sequence MRI showed intermingled dark signal intensity foci suggestive of intermingled thrombi. All nine patients who had undergone PET-CT displayed hypermetabolism. Diagnosis was delayed in 42.3% of the PAIS patients and those patients had a significantly shorter overall survival than patients whose diagnosis was not delayed (p < 0.05).ConclusionThe characteristic CT and clinical findings of PAIS may help achieve early diagnosis of PAIS and make better survival outcomes of patients. MRI and PET-CT can be used as second-line imaging modalities and could help distinguish PAIS from PTE and to plan clinical management.

According to recent studies, patients with COVID-19 have different feature characteristics on chest X-ray (CXR) than those with other lung diseases. This study aimed at evaluating the layer depths and degree of fine-tuning on transfer learning with a deep convolutional neural network (CNN)-based COVID-19 screening in CXR to identify efficient transfer learning strategies. The CXR images used in this study were collected from publicly available repositories, and the collected images were classified into three classes: COVID-19, pneumonia, and normal. To evaluate the effect of layer depths of the same CNN architecture, CNNs called VGG-16 and VGG-19 were used as backbone networks. Then, each backbone network was trained with different degrees of fine-tuning and comparatively evaluated. The experimental results showed the highest AUC value to be 0.950 concerning COVID-19 classification in the experimental group of a fine-tuned with only 2/5 blocks of the VGG16 backbone network. In conclusion, in the classification of medical images with a limited number of data, a deeper layer depth may not guarantee better results. In addition, even if the same pre-trained CNN architecture is used, an appropriate degree of fine-tuning can help to build an efficient deep learning model.

Open-mouth breathing during sleep is a risk factor for obstructive sleep apnea (OSA) and is associated with increased disease severity and upper airway collapsibility. The aim of this study was to investigate the effect of open-mouth breathing on the upper airway space in patients with OSA using three-dimensional multi-detector computed tomography (3-D MDCT). The study design included a case-control study with planned data collection. The study was performed at a tertiary medical center. 3-D MDCT analysis was conducted on 52 patients with OSA under two experimental conditions: mouth closed and mouth open. Under these conditions, we measured the minimal cross-sectional area of the retropalatal and retroglossal regions (mXSA-RP, mXSA-RG), as well as the upper airway length (UAL), defined as the vertical dimension from hard palate to hyoid. We also computed the volume of the upper airway space by 3-D reconstruction of both conditions. When the mouth was open, mXSA-RP and mXSA-RG significantly decreased and the UAL significantly increased, irrespective of the severity of OSA. However, between the closed- and open-mouth states, there was no significant change in upper airway volume at any severity of OSA. Results suggest that the more elongated and narrow upper airway during open-mouth breathing may aggravate the collapsibility of the upper airway and, thus, negatively affect OSA severity.

Lung cysts are commonly seen on computed tomography (CT), and cystic lung diseases show a wide disease spectrum. Thus, correct diagnosis of cystic lung diseases is a challenge for radiologists. As the first diagnostic step, cysts should be distinguished from cavities, bullae, pneumatocele, emphysema, honeycombing, and cystic bronchiectasis. Second, cysts can be categorized as single/localized versus multiple/diffuse. Solitary/localized cysts include incidental cysts and congenital cystic diseases. Multiple/diffuse cysts can be further categorized according to the presence or absence of associated radiologic findings. Multiple/diffuse cysts without associated findings include lymphangioleiomyomatosis and Birt-Hogg-Dubé syndrome. Multiple/diffuse cysts may be associated with ground-glass opacity or small nodules. Multiple/diffuse cysts with nodules include Langerhans cell histiocytosis, cystic metastasis, and amyloidosis. Multiple/diffuse cysts with ground-glass opacity include pneumocystis pneumonia, desquamative interstitial pneumonia, and lymphocytic interstitial pneumonia. This stepwise radiologic diagnostic approach can be helpful in reaching a correct diagnosis for various cystic lung diseases.

• Digital tomosynthesis offers new diagnostic options for airway lesions. • Digital tomosynthesis is more sensitive and accurate than radiography for airway lesions. • Digital tomosynthesis shows better image quality than radiography. • Assessment of lesion severity, via tomosynthesis is comparable to computed tomography.

Clinically significant extracardiac findings are common in patients undergoing CCTA with a considerable number of extracardiac findings being detected only on LDCT. We advise performing whole thorax LDCT prior to CCTA.

The MOD and the MMT are reliable criteria to diagnose acute appendicitis in children. An MOD > 0.57 cm and an MMT > 0.22 cm are the optimal criteria.