The histological structure of the liver is complex, consisting of hepatocytes, biliary epithelium, and mesenchymal cells. From this large variety of cells, a broad spectrum of benign and malignant liver lesions in originate. An accurate diagnosis of these lesions is mandatory for choosing an appropriate therapeutic approach. With the recent developments in hardware and software, magnetic resonance imaging (MRI) has emerged as the method of choice in the diagnostic workup of focal liver lesions, in particular in the pretherapeutic stage. The introduction of high-field MRI at 3.0T in the routine workup and the selective use of liver-specific contrast agents, including hepatobiliary and reticuloendothelial agents, have also strengthened the role of MRI in liver imaging. In this overview article, we will review the recent developments in 3.0-T MRI and MRI contrast agents in the diagnostic workup of the most common malignant liver tumors.
In in vitro and in vivo studies, episclerally sutured radio-opaque markers were evaluated as localizers for better determination of the clinical tumour volume prior to stereotactic radio-therapy of uveal melanoma. Four different types of markers were studied in vitro: tantalum marker, 2.5 mm in diameter; ring-shaped markers custom-designed in polymethyl methacrylate (PMMA), 2.6 mm and 3.0 mm in diameter; and barium-impregnated silicone rubber spheres, 2 mm in diameter. In vivo PMMA markers 3.0 mm in diameter and barium-impregnated silicone rubber spheres 2 mm in diameter were used. The best results were obtained with the barium-impregnated silicone rubber spheres both in vitro and in vivo. For the CT-delineation of selected uveal melanomas with either a flat discoid shape or flat tumour extensions or when adjacent serous retinal detachment is present, small episclerally sutured barium-impregnated silicone rubber spheres are useful as localizers for determining the clinical tumour volume.
As shown recently [1] 10% of all gastrointestinal tumors arising from gastrointestinal neuroendocrine cells diagnosed within 1 year are localized in the pancreas. Therefore pancreatic neuroendocrine (islet cell) tumors (PNET) are rare neoplasms and represent a heterogeneous group of tumors with distinct functional and biological behavior depending on clinical symptoms and tumor size.
Given the fact that a large number of radiological examinations using iodine-based contrast media (ICM) are performed in everyday practice, clinicians should be aware of potential ICM-induced thyroid dysfunction (TD). ICM can induce hyperthyroidism (Hyper) or hypothyroidism (Hypo) due to supraphysiological concentrations of iodine in the contrast solution. The prevalence of ICM-induced TD varies from 1 to 15%. ICM-induced Hyper is predominantly found in regions with iodine deficiency and in patients with underlying nodular goiter or latent Graves’ disease. Patients at risk for ICM-induced Hypo include those with autoimmune thyroiditis, living in areas with sufficient iodine supply. Most cases of ICM-induced TD are mild and transient. In the absence of prospective clinical trials on the management of ICM-induced TD, an individualized approach to prevention and treatment, based on patient’s age, clinical symptoms, pre-existing thyroid diseases, coexisting morbidities and iodine intake must be advised. Treatment of ICM-induced Hyper with antithyroid drugs (in selected cases in combination with sodium perchlorate) should be considered in patients with severe or prolonged hyperthyroid symptoms or in older patients with underlying heart disease. It is debated whether preventive therapy with methimazole and/or perchlorate prior to ICM administration is justified. In ICM-induced overt Hypo, temporary levothyroxine may be considered in younger patients with symptoms of Hypo, with an underlying autoimmune thyroiditis and in women planning pregnancy. Additional clinical trials with clinically relevant endpoints are warranted to further aid in clinical decision-making in patients with ICM-induced TD.
The aim of this study was to evaluate whether specific patterns of swallowing dysfunction occur in symptomatic patients after long-term intubation.Twenty-one patients (16 men, five women; mean age, 66 years) who presented with clinical signs of aspiration after long-term intubation (mean duration, 24.6 days) underwent videofluoroscopy. They were analyzed for functional abnormalities of the tongue, soft palate, epiglottis, hyoid and larynx, pharynx, and the upper esophageal sphincter. We assessed the presence or absence of aspiration, the type of aspiration (pre-, intra-, and postdeglutitive), and a spectrum of other swallowing abnormalities.There were 18 patients (86%) with radiologically proven aspiration. In another patient only laryngeal penetration occurred. There were 11 combinations of pre-, intra-, and postdeglutitive aspiration. Predeglutitive aspiration was predominant and present in 52% of our patients. We found functional abnormalities of the tongue in 48%, of the soft palate in 10%, of the epiglottis in 48%, of the pharynx in 71%, and of the upper esophageal sphincter in 24%.Patients who are symptomatic after undergoing long-term intubation do not develop a specific type or pattern of swallowing dysfunction or aspiration, but show a large variety of aspiration types and associated swallowing disorders. Nevertheless, videofluoroscopy has the ability to reveal complex deglutition disorders and to aid precise planning of individualized functional swallowing therapy.
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