This study indicates that an SI increase in the DN and GP on T1-weighted images is caused by serial application of the linear GBCA gadopentetate dimeglumine but not by the macrocyclic GBCA gadoterate meglumine. Clinical implications of this observation remain unclear.

Dear Editors, Rossi Espagnet and colleagues [1] reported significant increases of the globus pallidus-to-thalamus and the dentate nucleus-to-pons signal intensity ratios on unenhanced T1-weighted brain magnetic resonance images from children exposed to multiple injections of the macrocyclic gadolinium-based contrast agent gadoterate meglumine. However, this study has several important inconsistencies and limitations. In the Materials and Methods section, the authors wrote that each control subject was matched to a patient for age at both the first and the last MR examinations. The groups did not differ statistically at baseline but the results of the comparison at the last examination were not presented, thus precluding any interpretation of the signal intensity ratio increases. Age-dependent changes in native T1-weighted MR contrast of the brain may well account for these effects. In the Results section, the authors correlated the increases in the globus pallidus-to-thalamus and the dentate nucleus-to-pons signal intensity ratios to the number of gadolinium-based contrast agent injections. This association is not consistent with data from previous studies reporting an absence of correlation between these parameters in children after serial administrations of a linear gadolinium-based contrast agents [2, 3]. In Fig. 2, Rossi Espagnet and colleagues showed the relationships between the signal intensity ratios and the mean time intervals from the first administration. These graphs are misleading because the standard deviations of the time intervals at each injection were not presented. According to Table 1 in Rossi Espagnet's publication, the mean interval between MR examinations varied from 1 day to 532 days. It is likely that the mean time intervals reported in Fig. 2 were highly heterogeneous from one patient to another or between two injections in the same patient. Short time intervals of one to several days may have resulted in signal intensity increases due to incomplete wash-out of the gadolinium-containing molecules from the brain, and possibly to a significant signal intensity ratio increase in some patients. The authors excluded the effect of a history of radiation therapy to the brain as a possible cause for the signal intensity ratio increases. However, it is probable that these patients with brain tumors underwent additional radiother-apy sessions during the study period. Blood-brain barrier disruption induced by radiotherapy may contribute to signal intensity increases following macrocyclic gadolinium-based contrast agent injection. Some of the data reported by the authors in the Results section are not consistent with those that they presented graphically. The authors wrote that the globus pallidus-to-thalamus signal intensity mean value at first MR examination was 1.06 ±0.04 whereas it was rather equal to 1.048 according to Fig. 2. Such a mistake may have affected the statistical analyses. Moreover, Flood and colleagues [3] found that the dentate nucleus-to-pons signal intensity ratio difference be...

The present study found an increase in SI in the DN after serial injections of gadobenate dimeglumine. Further studies are needed to clarify the potential of different linear gadolinium-based contrast agents to cause SI increase in the DN.

Purpose To determine the effect of more than 20 serial injections of macrocyclic gadolinium-based contrast agents (GBCAs) on the signal intensity (SI) of the dentate nucleus (DN) on unenhanced T1-weighted magnetic resonance (MR) images. Materials and Methods In this retrospective, institutional review board-approved study, 33 patients who underwent at least 20 consecutive MR imaging examinations (plus an additional MR imaging for reference) with the exclusive use of macrocyclic GBCAs gadoterate meglumine and gadobutrol were analyzed. SI ratio differences were calculated for DN-to-pons and DN-to-middle cerebellar peduncle (MCP) ratios by subtracting the SI ratio at the first MR imaging examination from the SI ratio at the last MR imaging examination. One-sample t tests were used to examine if the SI ratio differences differed from 0, and Bayes factors were calculated to quantify the strength of evidence for each test. Results Patients underwent a mean of 23.03 ± (standard deviation) 4.20 GBCA administrations (mean accumulated dose, 491.21 mL ± 87.04 of a 0.5 M GBCA solution) with an average of 12.09 weeks ± 2.16 between every administration. Both ratio differences did not differ significantly from 0 (DN-to-pons ratio: -0.0032 ± 0.0154, P = .248; DN-to-MCP ratio: -0.0011 ± 0.0093, P = .521), and one-sided Bayes factors provided substantial to strong evidence against an SI ratio increase (Bayes factor for DN-to-pons ratio = 0.09 and that for DN-to-MCP ratio = 0.12). Conclusion The study indicates that 20 or more serial injections of macrocyclic GBCAs administered with on average 3 months between each injection are not associated with an SI increase in the DN. RSNA, 2016.

In this observational study, the application of the linear GBCA gadopentetate dimeglumine was associated with a DN-pons SI ratio increase, whereas subsequent applications of the macrocyclic GBCAs gadobutrol or gadoterate meglumine in the same patients were not. Rather, the current data tentatively suggest a decrease in preexisting hyperintensities over time when linear GBCAs are changed to macrocyclic GBCAs, potentially indicating a washout effect or precipitation of gadolinium. Future patient studies need to include control groups to replicate the present results, and additional animal studies should be conducted to clarify the underlying mechanism of the proposed SI decrease.

MRI parameters help to predict OS in a univariate Cox regression analysis, and increased rCBV is associated with shorter PFS in the multivariable model. In summary, however, our findings suggest that the relevance of MRI parameters is outperformed by clinical parameters in a multivariable analysis, which limits their prognostic value for survival prediction at the time of initial diagnosis.

Background Cardiovascular magnetic resonance (CMR) is the current reference standard for the quantitative assessment of ventricular function. Fast Strain-ENCoded (fSENC)-CMR imaging allows for the assessment of myocardial deformation within a single heartbeat. The aim of this pilot study was to identify obstructive coronary artery disease (oCAD) with fSENC-CMR in patients presenting with new onset of chest pain. Methods and results In 108 patients presenting with acute chest pain, we performed fSENC-CMR after initial clinical assessment in the emergency department. The final clinical diagnosis, for which cardiology-trained physicians used clinical information, serial high-sensitive Troponin T (hscTnT) values and—if necessary—further diagnostic tests, served as the standard of truth. oCAD was defined as flow-limiting CAD as confirmed by coronary angiography with typical angina or hscTnT dynamics. Diagnoses were divided into three groups: 0: non-cardiac, 1: oCAD, 2: cardiac, non-oCAD. The visual analysis of fSENC bull´s eye maps (blinded to final diagnosis) resulted in a sensitivity of 82% and specificity of 87%, as well as a negative predictive value of 96% for identification of oCAD. Both, global circumferential strain (GCS) and global longitudinal strain (GLS) accurately identified oCAD (area under the curve/AUC: GCS 0.867; GLS 0.874; p<0.0001 for both), outperforming ECG, hscTnT dynamics and EF. Furthermore, the fSENC analysis on a segmental basis revealed that the number of segments with impaired strain was significantly associated with the patient´s final diagnosis (p<0.05 for all comparisons). Conclusion In patients with acute chest pain, myocardial strain imaging with fSENC-CMR may serve as a fast and accurate diagnostic tool for ruling out obstructive coronary artery disease.

Coronary artery disease (CAD) represents a widespread burden to both individual and public health, steadily rising across the globe. The current guidelines recommend non-invasive anatomical or functional testing prior to invasive procedures. Both coronary computed tomography angiography (cCTA) and stress cardiac magnetic resonance imaging (CMR) are appropriate imaging modalities, which are increasingly used in these patients. Both exhibit excellent safety profiles and high diagnostic accuracy. In the last decade, cCTA image quality has improved, radiation exposure has decreased and functional information such as CT-derived fractional flow reserve or perfusion can complement anatomic evaluation. CMR has become more robust and faster, and advances have been made in functional assessment and tissue characterization allowing for earlier and better risk stratification. This review compares both imaging modalities regarding their strengths and weaknesses in the assessment of CAD and aims to give physicians rationales to select the most appropriate modality for individual patients.