The shape of the time-signal intensity curve is an important criterion in differentiating benign and malignant enhancing lesions in dynamic breast MR imaging. A type III time course is a strong indicator of malignancy and is independent of other criteria.

Mammography alone, and also mammography combined with breast ultrasound, seems insufficient for early diagnosis of breast cancer in women who are at increased familial risk with or without documented BRCA mutation. If MRI is used for surveillance, diagnosis of intraductal and invasive familial or hereditary cancer is achieved with a significantly higher sensitivity and at a more favorable stage.

An MRI acquisition time of 3 minutes and an expert radiologist MIP image reading time of 3 seconds are sufficient to establish the absence of breast cancer, with an NPV of 99.8%. With a reading time < 30 seconds for the complete AP, diagnostic accuracy was equivalent to that of the FDP and resulted in an additional cancer yield of 18.2 per 1,000.

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The accuracy of MR imaging is significantly higher than that of conventional imaging in screening high-risk women. Difficulties can be caused by an atypical manifestation of hereditary breast cancers at both conventional and MR imaging and by contrast material enhancement associated with hormonal stimulation.

In women at elevated familial risk, quality-assured MRI screening shifts the distribution of screen-detected breast cancers toward the preinvasive stage. In women undergoing quality-assured MRI annually, neither mammography, nor annual or half-yearly ultrasound or CBE will add to the cancer yield achieved by MRI alone.

Purpose:To measure 1 H relaxation times of cerebral metabolites at 3 T and to investigate regional variations within the brain. Materials and Methods:Investigations were performed on a 3.0-T clinical whole-body magnetic resonance (MR) system. T2 relaxation times of N-acetyl aspartate (NAA), total creatine (tCr), and choline compounds (Cho) were measured in six brain regions of 42 healthy subjects. T1 relaxation times of these metabolites and of myo-inositol (Ins) were determined in occipital white matter (WM), the frontal lobe, and the motor cortex of 10 subjects.Results: T2 values of all metabolites were markedly reduced with respect to 1.5 T in all investigated regions. T2 of NAA was significantly (P Ͻ 0.001) shorter in the motor cortex (247 Ϯ 13 msec) than in occipital WM (301 Ϯ 18 msec). T2 of the tCr methyl resonance showed a corresponding yet less pronounced decrease (162 Ϯ 16 msec vs. 178 Ϯ 9 msec, P ϭ 0.021). Even lower T2 values for all metabolites were measured in the basal ganglia. Metabolite T1 relaxation times at 3.0 T were not significantly different from the values at 1.5 T. Conclusion:Transverse relaxation times of the investigated cerebral metabolites exhibit an inverse proportionality to magnetic field strength, and especially T2 of NAA shows distinct regional variations at 3 T. These can be attributed to differences in relative WM/gray matter (GM) contents and to local paramagnetism. SEVERAL MAGNETIC RESONANCE (MR) studies performed at magnetic fields of 3 T or higher have shown that longitudinal relaxation times T1 of water protons in human brain tissue are prolonged at increasing field strength, whereas T2 of water is progressively reduced (1-5). However, until now, only a few reports on the measurement of proton T1 and T2 relaxation times of brain metabolites in vivo at magnetic fields beyond the 2 T threshold have been published. Accurate values for 1 H metabolite relaxation times are required for reliable and reproducible determination of absolute metabolite concentrations in cerebral tissue by MR spectroscopy (MRS).Analogous to the observed field dependence of water T2 relaxation times, the high-field MRS studies available up to now indicate a steady decrease of 1 H metabolite T2 values of N-acetyl aspartate (NAA), total creatine (tCr), and choline compounds (Cho) when progressing from 1.5-3 T and up to 7 T (6-10). While these data reveal a consistent trend, detailed information at 3 T, particularly regarding variations of metabolite T2 in different cerebral areas, is still incomplete. The aim of our study was to measure 1 H metabolite T2 in an extended set of brain regions covering a broad range of different mixtures of white matter (WM) and gray matter (GM) and with an adequate number of samples for each localization.High-field measurements of 1 H metabolite T1 have been performed at 3.0 T (6), 4.0 T (8), and 4.1 T (9). In contrast to the pronounced effects on water T1, and on water T2 and metabolite T2, no obvious influence of magnetic field strength on 1 H metabolite T1 values can as...

In 1988, the first contrast agent specifically designed for magnetic resonance imaging (MRI), gadopentetate dimeglumine (Magnevist®), became available for clinical use. Since then, a plethora of studies have investigated the potential of MRI contrast agents for diagnostic imaging across the body, including the central nervous system, heart and circulation, breast, lungs, the gastrointestinal, genitourinary, musculoskeletal and lymphatic systems, and even the skin. Today, after 25 years of contrast-enhanced (CE-) MRI in clinical practice, the utility of this diagnostic imaging modality has expanded beyond initial expectations to become an essential tool for disease diagnosis and management worldwide. CE-MRI continues to evolve, with new techniques, advanced technologies, and novel contrast agents bringing exciting opportunities for more sensitive, targeted imaging and improved patient management, along with associated clinical challenges. This review aims to provide an overview on the history of MRI and contrast media development, to highlight certain key advances in the clinical development of CE-MRI, to outline current technical trends and clinical challenges, and to suggest some important future perspectives.FundingBayer HealthCare.Electronic supplementary materialThe online version of this article (doi:10.1007/s12325-015-0275-4) contains supplementary material, which is available to authorized users.