A Study to Evaluate the Role of Three-Dimensional Pseudo-Continuous Arterial Spin Labelling in Acute Ischemic Stroke.

Introduction Magnetic resonance imaging (MRI) is well known to detect ischemic brain tissue and evaluate the tissue vulnerable to infarction. Diffusion-weighted imaging (DWI) has been a mainstay of stroke evaluation but has a few shortcomings, as it generally indicates only the core of ischemia and does not provide information regarding the tissue at risk or the ischemic penumbra surrounding the infarct. Perfusion imaging identifies brain tissue that has reduced blood flow as a potential target for reperfusion therapy. Arterial spin labelling (ASL) is a new non-invasive, non-contrast MRI perfusion sequence used to detect areas of hypoperfusion qualitatively and quantitatively and also identify the area at risk, i.e., the penumbra, in acute ischemic stroke. The most important component of the imaging is to determine the ischemic penumbra. One of the working definitions of penumbra is brain tissue that is ischemic but not yet infarcted and is at risk of further damage unless the flow is rapidly restored. Hence, perfusion-diffusion mismatch provides a realistic target for potential intervention. The aim of our study is to assess the role of ASL imaging in identifying the penumbra and providing insight into the management of acute ischemic stroke. Materials and methods Patients who presented with symptoms of acute ischemic stroke were included in the study, and an MRI stroke protocol comprising DWI, fluid-attenuated inversion recovery (FLAIR), ASL, and magnetic resonance angiogram (MRA) sequences was done. Post-thrombolysis, a follow-up MRI was done using DWI, ASL, and MRA to see the restoration of perfusion in the ischemic penumbra. Three-dimensional pseudo-continuous ASL (in our study, ASL refers to pseudo-continuous ASL) is included in the stroke protocol in cases of acute ischemic stroke and assessed qualitatively. Results Our study included 43 patients (n = 43), of whom 39.5% (17 patients) belong to the age group of 51-60 years and 2.3% (one patient) are in the age group of 21-30 years. All 43 cases demonstrated DWI-FLAIR mismatch, suggestive of ischemic stroke within the window period, and all 43 cases showed DWI-ASL mismatch, suggestive of a large yet potentially salvageable peri-infarct ischemic penumbra. The most common territory involved was the middle cerebral artery (MCA), and the posterior cerebral artery (PCA) was the least commonly involved territory. We had one case involving the MCA-PCA watershed zone. Conclusion Arterial spin labelling is a novel, non-invasive, non-contrast MRI sequence with the capability to provide qualitative information regarding the salvageable ischemic penumbra, and timely management prevents the progression of the penumbra. The incorporation of ASL as part of the standard neuroimaging protocol aids in the management of acute stroke, giving insight into the prediction of outcome.

Radiological Manifestations of Rhino-Orbito-Cranial Mucormycosis in COVID-19 Patients Correlated With Pathological and Clinical Outcomes and Emphasis on Magnetic Resonance Imaging-Based Scoring System.

There was tremendous increase in the number of cases of mucormycosis among patients affected by coronavirus disease 2019 (COVID-19) during the second wave of pandemic in South Asian countries. This invasive fungal infection primarily affects paranasal sinuses and can have orbito-facial and intracranial extension. We are presenting the radiological findings of invasive mucormycosis with pathological and clinical outcome correlation. It is important for radiologists to have the knowledge of various presentations of this opportunistic infection for early diagnosis and helping clinicians in planning the appropriate line of management. The study also emphasizes on the correlation between the extent of involvement with clinical outcome and we proposed a magnetic resonance imaging (MRI) based scoring system to standardize and prognosticate the patients affected with mucormycosis. MATERIALS AND METHODS: We utilized GE 1.5 tesla, 16-channeled MRI machine for scanning the clinically suspected mucormycosis patients and did plain and contrast study of the paranasal sinuses, orbito-facial study and included brain as and when required. Images were acquired in axial, coronal, and sagittal planes using T1, T2, and fat-saturated short tau inversion recovery sequences (STIR), fat-saturated contrast sequences for better evaluation of the extent of the disease. Diffusion-weighted sequence was also acquired to detect ischemic changes in optic nerve or brain parenchyma. Contrast study was used to detect any major vessel occlusion or cavernous sinus thrombosis in the study population. RESULTS: Total number of cases (n) included in the study were 32. The mean age group was 41-50 years with the median age was 47 years. Out of 32 cases (n=32), in 16 cases (50%) the disease was limited only to the paranasal sinuses and in remaining 16 (50%) cases, disease has spread to other regions such as orbits, facial soft tissues, optic nerve, and brain parenchyma. All the 18 cases with Mild score (MRI ROCM score 1-3) survived and all those with severe score (2 cases) (MRI ROCM score 7-10) did not survive. CONCLUSION: During the second wave of COVID-19 pandemic, we observed a significant rise in acute invasive mucormycosis infection primarily involving the paranasal sinuses and spread to orbito-facial, cerebral parenchyma causing related complications and hence increased morbidity and death. Radiologically, using MRI, it was effectively possible to detect early extrasinonasal spread and other fatal complications thereby guiding the physicians and surgeons in the proper early aggressive management of the disease. Here, we have described the radiological characteristics of paranasal sinus mucormycosis and its spread to other regions. We also proposed an MRI-based Scoring System for standardized assessment of the disease severity. We observed in our study that the extent of disease on MRI is directly correlating with mortality.

Safety and Feasibility of Antibiotic De-escalation in Critically Ill Children With Sepsis - A Prospective Analytical Study From a Pediatric ICU.

Introduction: De-escalation is the key to balance judicious antibiotic usage for life-threatening infections and reducing the emergence of antibiotic resistance caused by antibiotic overuse. Robust evidence is lacking regarding the safety of antibiotic de-escalation in culture negative sepsis. Materials and Methods: Children admitted to the PICU during the first 6 months of 2019 with suspected infection were included. Based on the clinical condition, cultures and septic markers, antibiotics were de-escalated or continued at 48-72 h. Outcome data like worsening of primary infection, acquisition of hospital acquired infection, level of ICU support and mortality were captured. Results: Among the 360 admissions, 247 (68.6%) children received antibiotics. After excluding 92 children, 155 children with 162 episodes of sepsis were included in the study. Thirty four episodes were not eligible for de-escalation. Among the eligible group of 128 episodes, antibiotics were de-escalated in 95 (74.2%) and continued in 33 (25.8%). The primary infection worsened in 5 (5.2%) children in the de-escalation group and in 1 (3%) in non de-escalation group [Hazard ratio: 2.12 (95%CI: 0.39-11.46)]. There were no significant differences in rates of hospital acquired infection, mortality or length of ICU stay amongst the groups. Blood cultures and assessment of clinical recovery played a major role in de-escalation of antibiotics and the clinician's hesitation to de-escalate in critically ill culture negative children was the main reason for not de-escalating among eligible children. Conclusion: Antibiotic de-escalation appears to be a safe strategy to apply in criticallly ill children, even in those with negative cultures.