Tens of millions of contrast-enhanced magnetic resonance imaging (MRI) exams are performed annually around the world. The contrast agents, which improve diagnostic accuracy, are almost exclusively small, hydrophilic gadolinium(III) based chelates. In recent years concerns have arisen surrounding the long-term safety of these compounds, and this has spurred research into alternatives. There has also been a push to develop new molecularly targeted contrast agents or agents that can sense pathological changes in the local environment. This comprehensive review describes the state of the art of clinically approved contrast agents, their mechanism of action, and factors influencing their safety. From there we describe different mechanisms of generating MR image contrast such as relaxation, chemical exchange saturation transfer, and direct detection and the types of molecules that are effective for these purposes. Next we describe efforts to make safer contrast agents either by increasing relaxivity, increasing resistance to metal ion release, or by moving to gadolinium(III)-free alternatives. Finally we survey approaches to make contrast agents more specific for pathology either by direct biochemical targeting or by the design of responsive or activatable contrast agents.

Chemistry of MRI Contrast Agents: Current Challenges and New Frontiers

Emerging evidence has linked MRI signal changes in deep nuclei of the brain with repeated administration of gadolinium-based contrast agents. Gadolinium deposits have been confirmed in brain tissue, most notably in the dentate nuclei and globus pallidus. Although some linear contrast agents appear to cause greater MRI signal changes than some macrocyclic agents, deposition of gadolinium has also been observed with macrocyclic agents. However, the extent of gadolinium deposition varies between agents. Furthermore, the clinical significance of the retained gadolinium in the brain, if any, remains unknown. No data are available in human beings or animals to show adverse clinical effects due to the gadolinium deposition in the brain. On behalf of the International Society for Magnetic Resonance in Medicine, we present recommendations for the clinical and research use of gadolinium-based contrast agents. These recommendations might evolve as new evidence becomes available.

Gadolinium deposition in the brain: summary of evidence and recommendations

Gadolinium chelates are widely used as contrast media for magnetic resonance imaging. The approved gadolinium-based contrast agents (GBCAs) have historically been considered safe and well tolerated when used at recommended dosing levels. However, for nearly a decade, an association between GBCA administration and the development of nephrogenic systemic fibrosis (NSF) has been recognized in patients with severe renal impairment. This has led to modifications in clinical practices aimed at reducing the potential and incidence of NSF development. Newer reports have emerged regarding the accumulation of gadolinium in various tissues of patients who do not have renal impairment, including bone, brain, and kidneys. Despite the observations of gadolinium accumulation in tissues regardless of renal function, very limited clinical data regarding the potential for and mechanisms of toxicity is available. This significant gap in knowledge warrants retrospective cohort study efforts, as well as prospective studies that involve gadolinium ion (Gd3+) testing in patients exposed to GBCA. This review examines the potential biochemical and molecular basis of gadolinium toxicity, possible clinical significance of gadolinium tissue retention and accumulation, and methods that can limit gadolinium body burden.

/pdf/gadolinium-based-contrast-agent-toxicity-a-review-of-known-23m5jxoa9k.pdf

Gadolinium-based contrast agent toxicity: a review of known and proposed mechanisms

Child-Pugh Versus MELD Score for the Assessment of Prognosis in Liver Cirrhosis: A Systematic Review and Meta-Analysis of Observational Studies.

As one of the causes of stroke, dementia and migraine, cerebral autosomal dominant with subcortical infarcts and leukoencephalopathy（CADASIL） has been paid increasing attention. Notch3 mutation is the molecular genetics basis of CADASIL. The detection of gene mutation and skin or muscle biopsy are the main tools in the diagnosis of CADASIL.

Key words: 
CADASIL ;  Notch3

Cadasil

Introduction. Angiomyolipomas (AML) are benign neoplasms composed of fat,
 smooth muscle and thick-walled blood vessels in varying proportions. These
 tumors have a significant female predominance. Case report. We reported a
 61-year-old man with spontaneous rupture of AML. Computerized tomography
 revealed a change in morphology of both kidneys. Multiple lesions of fat
 density with dilated blood vessels were found in the left kidney. The right
 retroperitoneum was obliterated with a giant heterogeneous mass originating
 from the right kidney with a massive hemorrhage, active extravasations,
 compression of inferior the vena cava and intraperitoneal collections. After
 radical nephrectomy, histological examination revealed that the tumor was
 composed of relative proportions of fat, smooth muscle and blood vessels. We
 incidentally found small renal adenoma. Conclusion. The true nature of AML is
 unclear, but they are usually classified as hamartomas. Angiomyolipomas are
 generally benign lesions, although the epithelioid angiomyolipoma, a subtype
 that occurs in about 3% of cases, can behavior aggressively. [Projekat
 Ministarstva nauke Republike Srbije, br. 41017]

http://www.doiserbia.nb.rs/img/doi/0042-8450/2014/0042-84501404408P.pdf

Bilateral giant angiomyolipomas revealed after massive retroperitoneal hemorrhage - A case report.

Radiomorphometric analysis of human pituitary gland during the aging process

The study involved 27 lateral cervical schwannomas surgically treated in the last 40 years utilizing either partial or total resection. The study aims to compare the results of total and partial resection of spinal lateral schwannoma and to assess the values of partial resection of large lateral cervical schwannomas. We performed a retrospective analysis of 27 patients operated for lateral cervical schwannomas in the period 1971–2010, out of which 11 had partial resection. The average follow-up of the patients was 136.4 months, comparing pre- and postoperative clinical picture, time to relapse, dynamics of yearly growth of schwannomas, and the need for re-resection. The average period of preoperative complaint in lateral cervical schwannomas was 19.6 months. Unilateral cervicobrachialgia as a manifestation of radiculopathy was observed in 85% of LCSs, and, was, as a rule the first symptom of the disease. Surgical treatment of 27 patients with LCSs resulted in recovery or improvement of complaints in 80% of cases. The treatment effect did not depend on the degree of resection. Reoperation was done, on average, 16.3 years after partial resection. The residues of lateral cervical schwannomas stopped growing 15 years after partial resection and underwent cystic degeneration. Partial resection of lateral cervical schwannomas is an excellent alternative to total resection, not only for the elderly or in cases of increased surgical risk, but also as a method of choice since it is more readily available to a larger number of surgeons and associated with low percentages of surgically relevant relapses and high percentages of improvement.

Lateral intra-extraspinal cervical schwannomas: Partial versus total resection

Carotid artery stenosis is a widespread disease and it is one of the most significant risk factors for the development of ischemic stroke. The risk of ischemic stroke increases with the increase in the degree of carotid artery stenosis. Although the relation between carotid artery stenosis and other risk factors (arterial hypertension, hyperlipidemia, diabetes, etc.) has not been precisely determined in relation to the development, course and outcome of the ischemic stroke, the degree of this association is considered important for the development of ischemic stroke. The aim of the study was to determine the significance of carotid artery stenosis in patients with ischemic stroke and to estimate the degree of association between carotid artery stenosis and other risk factors in the development of ischemic stroke. The study included patients with ischemic stroke treated at the Cerebrovascular Diseases Department of the Neurology Clinic. The data were obtained from histories and from color Doppler (CD) examination of extracranial blood vessels of the neck. The highest percentage of patients with stroke had carotid artery stenosis (p<0.05). Of these patients, the highest percentage were with stenosis degree less than 60% (p<0.05). The patients with more than two risk factors, in addition to stenosis, more often had ischemic stroke (p<0.05). In the group without carotid artery stenosis, patients with large number of risk factors also had a higher risk of developing the disease, compared to those who did not have the combined risk factors (p<0.05). However, patients with ischemic stroke without carotid artery stenosis who had several other risk factors also had the same risk of developing ischemic stroke as the patients with carotid artery stenosis without combined risk factors. Carotid artery stenosis is a risk factor in ischemic stroke. In patients with several risk factors, stenosis is a high risk factor for ischemic stroke. Patients without stenosis but with several other risk factors have the same risk of developing ischemic stroke as patients with stenosis and without other risk factors. Acta Medica Medianae 2016;55(2):40-45.

Carotid artery stenosis as a risk factor for the occurrence of ischemic stroke

Head and neck infections are a group of disorders that can be accompanied by serious complications with an extent that is hard to estimate. Although their occurrence has significantly decreased due to the use of antibiotic and improvements in oral hygiene in modern times, there still exists a high rate of morbidity and mortality of these infections. A complex anatomy and communications between spaces in this region favor the spread of these processes and can lead to life-treating conditions such as airway obstruction, empyema, mediastinitis, thrombophlebitis, pericarditis and septic shock. Computerized tomography (CT), as a method of choice in emergency conditions of the head and neck region, allows a fast and accurate diagnosis, estimation of the disease spread and potential complications. Acta Medica Medianae 2017;56(2):70-77.

/pdf/importance-of-computed-tomography-in-the-diagnosis-of-head-msbcygqyez.pdf

Importance of computed tomography in the diagnosis of head and neck infections

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