Target sign in COVID-19, radiological interpretation and diagnostic contribution of digital thoracic tomosynthesis.

INTRODUCTION: Our objectives are: To describe the radiological semiology, clinical-analytical features and prognosis related to the target sign (TS) in COVID-19. To determine whether digital thoracic tomosynthesis (DTT) improves the diagnostic ability of radiography. MATERIAL AND METHODS: Retrospective, descriptive, single-centre, case series study, accepted by our ethical committee. Radiological, clinical, analytical and follow-up characteristics of patients with COVID-19 and TS on radiography and DTT between November 2020 and January 2021 were analysed. RESULTS: Eleven TS were collected in 7 patients, median age 35 years, 57% male. All TS presented with a central nodule and a peripheral ring, and in at least 82%, the lung in between was of normal density. All TS were located in peripheral, basal regions and 91% in posterior regions. TS were multiple in 43%. Contiguous TS shared the peripheral ring. Other findings related to pneumonia were associated in 86% of patients. DTT detected 82% more TS than radiography. Only one patient underwent a CT angiography of the pulmonary arteries, positive for acute pulmonary thromboembolism. Seventy-one per cent presented with pleuritic pain. No distinctive laboratory findings or prognostic worsening were detected. CONCLUSIONS: TS in COVID-19 predominates in peripheral and declining regions and can be multiple. Pulmonary thromboembolism was detected in one case. It occurs in young people, frequently with pleuritic pain and does not worsen the prognosis. DTT detects more than 80 % of TS than radiography.

Patients with severe polytrauma: management and imaging protocols.

Traumatic injuries can be severe and complex, requiring the coordinated efforts of a multidisciplinary team. Imaging tests play a fundamental role in rapid and accurate diagnosis. In particular, whole-body computed tomography (CT) has become a key tool. There are different CT protocols depending on the patient's condition; whereas dose-optimized protocols can be used in stable patients, time/precision protocols prioritizing speed at the cost of delivering higher doses of radiation should be used in more severe patients. In unstable patients who cannot be examined by CT, X-rays of the chest and pelvis and FAST or e-FAST ultrasound studies, although less sensitive than CT, enable the detection of situations that require immediate treatment. This article reviews the imaging techniques and CT protocols for the initial hospital workup for patients with multiple trauma.

Fractures of the limbs: basic concepts for the emergency department.

Traumatic injuries of the limbs are very common and account for a large number of imaging examinations, especially in emergency departments. These injuries can often be resolved if they are recognized and treated appropriately. Their diagnosis requires a complete clinical assessment and the correct interpretation of the appropriate imaging tests. Radiologists play an important role, especially in diagnosing lesions that can go undetected. To this end, radiologists need to know the normal anatomy and its variants, the mechanisms of injury, and the indications for different imaging tests, among which plain-film X-rays are the main technique for the initial evaluation. This article aims to review the relevant characteristics of limb fractures in adults and of lesions that can be associated with these fractures, as well as how to describe them to ensure appropriate clinical management.

Is positive oral contrast material necessary for computed tomography in patients with suspected acute abdomen? / Ante la sospecha de abdomen agudo, ¿es necesario el contraste oral positivo en la tomografía computarizada?

The number of computed tomography studies done in emergency departments has increased substantially, and with this increase the controversy about whether positive oral contrast agents are necessary in all patients has also grown. The great image quality provided by multidetector computed tomography scanners, the increase in intraabdominal fat (as a natural element that provides contrast for separating the bowel loops) related with the increased prevalence of obesity in the population, and the potential drawbacks associated with the use of high-density oral contrast agents argue against the generalized us of these agents. This article aims to evaluate the effects of omitting the use of this type of oral contrast material for computed tomography examinations required in the emergency department for suspicion of acute abdominal pathology through an efficient literature search among recent publications.

[Can MRI determine whether acute or chronic processes predisposing conditions are present in spontaneous osteonecrosis of the knee?]. / Resonancia magnética de la osteonecrosis espontánea de la rodilla: ¿existe un proceso agudo o crónico predisponente?

OBJECTIVE: To analyze possible underlying causes of spontaneous osteonecrosis of the knee in adults in function of the lesion's behavior on magnetic resonance imaging (MRI): acute lesion (insufficiency fractures) or chronic lesion (osteoarthritic degeneration). MATERIAL AND METHODS: We retrospectively evaluated knee MRI studies in 48 patients who fulfilled criteria for spontaneous osteonecrosis. A total of 51 subchondral lesions were included and classified in two groups: those in which linear images were present (Group A) and those in which linear images were not present (Group B). We recorded the location and size of the lesions, their signal intensity, their relation with bone edema, ipsilateral meniscal tear and abnormalities in the adjacent cartilage, as well as the presence of osteoarthritis. RESULTS: We studied 28 men and 20 women (mean age, 55.1+/-18.0 years). Linear images were present in 58.5% of lesions (group A) and absent in 41.2% (group B). The most common location in both groups was the internal femoral condyle (56.7% in group A and 52.4% in group B), and 88.2% of lesions were hypointense on T1-weighted and fat suppressed proton density sequences. The mean size of the anteroposterior and transversal diameters was 11.9+/-3.6 x 9.4+/-3.9 mm in group A and 10.9+/-5.1 x 10.5+/-4.5 mm in group B. The predominant bone edema was severe (grade 2-3) in group A and mild (grade 0-1) in group B (p=0.033). Defects in the cartilage ipsilateral to the subchondral lesion were more common in group B than in group A, although this difference was not significant (76.2% and 56.7%, respectively; p=0.33). The frequency of ipsilateral meniscal tear was similar in the two groups (56.7% in group A and 57.1% in group B; p=0.97). CONCLUSION: Knowing the MRI findings for spontaneous osteonecrosis and evaluating other data (type of lesion, bone edema, meniscal tear, and ipsilateral cartilage defects) can help determine the primary predisposing process. Linear lesions might be related to an acute process (insufficiency fractures) and non-linear lesions might be related to a chronic process (osteoarthritis).

[Uncommon localization of osteomyelitis]. / Osteomielitis de localización inusual.

Group A beta-hemolytic streptococcus (GAS) causes almost 10% of acute hematogenous osteomyelitis (AHOM). These entities are frequently located in long bones (femur, tibia and humerus), and only 6-8% of all AHOM are located in the pelvis. This uncommon localization delays diagnosis and can lead to inappropriate management, with negative effects on outcomes. We present the case of a 6-year-old boy with high fever, pain in the right hip and difficulty in walking due to pelvic AHOM and septic shock caused by GAS. We also provide a review of the literature.

[Spontaneous pneumomediastinum: descriptive study of our experience with 36 cases]. / Neumomediastino espontáneo: estudio descriptivo de nuestra experiencia basada en 36 casos.

Spontaneous pneumomediastinum is defined as a primary process characterized by the presence of air or gas in the mediastinum. We report all the cases of spontaneous pneumomediastinum diagnosed in our hospital between January 1996 and December 2004. We developed a protocol for data collection that included the following: medical history, triggers, signs, radiology, treatment, hospital stay, and complications. During this period we diagnosed 36 cases--25 men (69.4%) and 11 women (27.5%)--with a mean age of 36.8 years (range, 11-90 years) and a mean hospital stay of 8.56 days (range, 1-53 days). The most common clinical presentation was chest pain, either isolated (27%) or with associated dyspnea (19.4%). A triggering factor was identified for 14 patients (38.8%). There was no associated morbidity or mortality. In view of our findings, we concluded that spontaneous pneumomediastinum is an uncommon entity with considerable clinical variability and that correct diagnosis requires a high level of suspicion. Radiography provides the best evidence for diagnosis.