The use of GBCAs was initially considered safe without reported acute adverse events or long-term risks. In addition, GBCA was occasionally used for patients unsuitable for iodine-based contrast agent in CT examinations. The effect of GBCAs in MRI is rendering a higher signal on T1-weighted images due to shortening of T1 relaxation time. Gadolinium-based contrast agents (GBCAs) in MRI were introduced in clinical practice in the 1980s to increase lesion detection and improve the disease characterization for many cerebral and vascular pathologies investigated with MRI. However, some diagnoses still require contrast-enhanced imaging for a complete examination. In general, non-contrast-enhanced techniques showed comparable diagnostic performance to contrast-enhanced MRI for specific diagnostic questions. These specific diseases include primary brain tumors, metastases, abscess, multiple sclerosis, and vascular conditions such as aneurysm, arteriovenous malformation, arteriovenous fistula, intracranial carotid artery occlusive disease, hemorrhagic, and ischemic stroke. Ten common diseases were identified for which studies reported comparisons of non-contrast-enhanced and contrast-enhanced MRI. Non-contrast-enhanced MRIs discussed in this review are arterial spin labeling (ASL), time of flight (TOF), phase contrast (PC), diffusion-weighted imaging (DWI), magnetic resonance spectroscopy (MRS), susceptibility weighted imaging (SWI), and amide proton transfer (APT) imaging.
Advantages and disadvantages together with the diagnostic performance of each method are detailed. Clinical studies on the diagnostic performance of non-contrast-enhanced as well as contrast-enhanced MRI methods, both well established and newly proposed, were included. This review focuses on non-contrast-enhanced MRI techniques that can serve as alternatives for the use of GBCAs. Some linear GBCAs were restricted from use by the European Medicines Agency (EMA) in 2017.
Hence, new guidelines from the International Society for Magnetic Resonance in Medicine advocate cautious use of GBCA in clinical and research practice. Gadolinium deposition has also been found in deep brain structures, although it is of unclear clinical relevance. However, some non-ionic linear GBCAs have been associated with the development of nephrogenic systemic fibrosis in patients with kidney failure. These agents, introduced in the late 1980s, are in wide use today. While there is limited sustainability research in the context of the developing world, this study contributes by bridging this gap in the present literature.Gadolinium-based contrast agents (GBCAs) increase lesion detection and improve disease characterization for many cerebral pathologies investigated with MRI. This paper extends the extant literature by exploring sustainability implementation in the Pakistani hotel industry. It is suggested that the government, community organizations and the private sector firms need to actively collaborate to promote the sustainability agenda. This study identifies some practical issues and challenges in relation to sustainability implementation in the Pakistani context. Overall, the central focus of the hotels is on developing commercial performance, whereas some fragmented social and environmental sustainability initiatives are implemented on an ad hoc basis. The results suggest that sustainability is only partially integrated into the business strategy for most of the sample hotels, and a systematic approach to sustainability is currently lacking. Semi-structured interviews are conducted with the senior hotel managers. sustainability practices adopted by the Pakistani hotel industry.
The authors follow an exploratory multiple case study design to study the. Sustainability is a relatively under-researched notion from the perspective of the developing world, and in particular, the research lacks evidence from the Pakistani hotel industry. This paper aims to look at the sustainability practices adopted by the Pakistani hotel industry.
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