For the last 15 years, super‐resolution (SR) algorithms have successfully been applied to magnetic resonance imaging (MRI) data to increase the spatial resolution of scans after acquisition has been performed, thus facilitating the doctors' diagnosis. The variety of application and techniques has grown ever since, especially in the MRI modality, showing the interest of the community to such postacquisition processing. This article presents a review of the general principle of SR as well as how this principle has been adapted to MRI data. The main algorithms and the principal acquisition protocols are detailed for both static and moving subjects. The presented strategies are discussed and compared according to the data specificities. Later, different ways of measuring the resolution enhancement and quantify the benefit of SR are detailed. Finally, unexplored perspectives on the application of SR to MRI data are discussed. © 2012 Wiley Periodicals, Inc. Concepts Magn Reson Part A 40A: 306–325, 2012.

Coronavirus disease 2019, caused by the severe acute respiratory syndrome coronavirus 2, has been declared a pandemic by the World Health Organization. As the pandemic evolves rapidly, there are data emerging to suggest that pregnant women diagnosed as having coronavirus disease 2019 can have severe morbidities (up to 9%). This is in contrast to earlier data that showed good maternal and neonatal outcomes. Clinical manifestations of coronavirus disease 2019 include features of acute respiratory illnesses. Typical radiologic findings consists of patchy infiltrates on chest radiograph and ground glass opacities on computed tomography scan of the chest. Patients who are pregnant may present with atypical features such as the absence of fever as well as leukocytosis. Confirmation of coronavirus disease 2019 is by reverse transcriptase-polymerized chain reaction from upper airway swabs. When the reverse transcriptasepolymerized chain reaction test result is negative in suspect cases, chest imaging should be considered. A pregnant woman with coronavirus disease 2019 is at the greatest risk when she is in labor, especially if she is acutely ill. We present an algorithm of care for the acutely ill parturient and guidelines for the protection of the healthcare team who is caring for the patient. Key decisions are made based on the presence of maternal and/or fetal compromise, adequacy of maternal oxygenation (SpO 2 >93%) and stability of maternal blood pressure. Although vertical transmission is unlikely, there must be measures in place to prevent neonatal infections. Routine birth processes such as delayed cord clamping and skin-to-skin bonding between mother and newborn need to be revised. Considerations can be made to allow the use of screened donated breast milk from mothers who are free of coronavirus disease 2019. We present management strategies derived from best available evidence to provide guidance in caring for the high-risk and acutely ill parturient. These include protection of the healthcare workers caring for the coronavirus disease 2019 gravida, establishing a diagnosis in symptomatic cases, deciding between reverse transcriptase-polymerized chain reaction and chest imaging, and management of the unwell parturient.

Perioperative internal iliac artery occlusion balloon placement is a safe and minimally invasive technique that reduces intraoperative blood loss and transfusion requirements in patients with placenta accreta and its variants undergoing cesarean delivery.

Objective To estimate and compare performance of diffusion weighted imaging (DWI) with other MR imaging techniques including T2-weighted MR imaging (T2WI) for prostate cancer (PC) detection. Methods The PubMed and Scopus electronic databases searches for “prostate”, “cancer”, “diffusion weighted imaging”, “magnetic resonance imaging” were completed up to December 2010. All included studies had histopathological correlation. 2 × 2 contingency data were constructed for each study. A Bayesian receiver operating characteristics (ROC) model was used across studies to determine sensitivity, specificity, and area under full or partial receiver operator curve (AUROC). Results Nineteen publications consisting of a total of 5,892 lesions were analysed. Based on a 95% CI, DWI alone yielded significantly better AUROC, sensitivity and specificity (0.85, 0.69, 0.89) than T2WI alone (0.75, 0.6, 0.76). DWI/T2WI (0.73, 0.7, 0.83) showed similar AUROC but significantly better sensitivity and specificity than T2WI alone. DWI and DWI/T2WI yielded similar overall sensitivity, but DWI alone showed better overall specificity than DWI/T2WI. At specificities above 80%, DWI/T2WI yielded similar (partial) AUROC (0.138) to DWI alone (0.129), and was significantly better than T2WI alone (0.07). DWI alone and DWI/T2WI appear superior to dynamic contrast enhanced imaging alone (AUROC 0.79, sensitivity 0.58, specificity 0.82). Conclusion DWI appears to improve diagnostic performance and can be a useful adjunct to conventional anatomic imaging for identifying tumour foci in PC.

Imaging of gastroenteropancreatic neuroendocrine tumors can be broadly divided into anatomic and functional techniques. Anatomic imaging determines the local extent of the primary lesion, providing crucial information required for surgical planning. Functional imaging, not only determines the extent of metastatic disease spread, but also provides important information with regard to the biologic behavior of the tumor, allowing clinicians to decide on the most appropriate forms of treatment. We review the current literature on this subject, with emphasis on the strengths of each imaging modality.

Consensus guidelines for radiological diagnosis of hepatocellular carcinoma (HCC) have been drafted by several large international working groups. This article reviews the similarities and differences between the most recent guidelines proposed by the American Association for Study of Liver Diseases and the Asian Pacific Association for the Study of the Liver. Current evidence for the various imaging modalities for diagnosis of HCC and their relevance to the consensus guidelines are reviewed.

Urothelial carcinoma is the most common histologic subtype of bladder cancer, and accurate local staging of this tumor is crucial for management. Traditionally, local staging relied on biopsy. With increasing accuracy of imaging modalities and techniques, imaging also plays an important role in the multidisciplinary care of patients with this disease.

Highlights Platypnea-orthodeoxia syndrome (POS) is observed in COVID-19 acute respiratory distress syndrome (ARDS) survivors. POS is associated with older age, lower body mass index and varying degrees of dyspnea. Arterial to end-tidal carbon dioxide and alveolar to arterial oxygen partial pressure differences were persistently elevated. POS is likely a gravitational exacerbation of intrapulmonary shunt in ARDS due to COVID-19 specific changes. POS may cause alarm and requires adjustment in the rehabilitation approach during the recovery period.