Cerebral Hemodynamics, Right-to-Left Shunt and White Matter Hyperintensities in Patients with Migraine with Aura, Young Stroke Patients and Controls.

Background: Migraine with aura (MA) patients present an increased risk of cerebrovascular events. However, whether these patients present an increased white matter hyperintensities (WMHs) load compared to the general population is still under debate. Our study aimed to evaluate the relationship between cerebral hemodynamics, right-to-left shunt (RLS) and WMHs in MA patients, young patients with cryptogenic stroke or motor transient ischemic attack (TIA) and controls. Methods: We enrolled 30 MA patients, 20 young (<60 years) patients with cryptogenic stroke/motor TIA, and 10 controls. All the subjects underwent a transcranial Doppler bubble test to detect RLS and cerebral hemodynamics assessed by the breath holding index (BHI) for the middle (MCA) and posterior (PCA) cerebral arteries. Vascular risk factors were collected. The WMHs load on FLAIR MRI sequences was quantitatively assessed. Results: The stroke/TIA patients presented a higher prevalence of RLS (100%) compared with the other groups (p < 0.001). The MA patients presented a higher BHI compared with the other groups in the PCA (p = 0.010) and higher RLS prevalence (60%) than controls (30%) (p < 0.001). The WMHs load did not differ across groups. BHI and RLS were not correlated to the WMHs load in the groups. Conclusions: A preserved or more reactive cerebral hemodynamics and the presence of a RLS are likely not involved in the genesis of WMHs in MA patients. A higher BHI may counteract the risk related to their higher prevalence of RLS. These results need to be confirmed by further studies to be able to effectively identify the protective role of cerebral hemodynamics in the increased RLS frequency in MA patients.

Anterior pituitary gland T1 signal intensity is influenced by time delay after injection of gadodiamide.

To test the hypothesis of washout from the anterior pituitary (AP) gland after serial injections of gadodiamide. We included 59 patients with history of at least 5 injections of gadodiamide. Values of mean signal intensity of the AP and of the central pons were measured on unenhanced sagittal T1-weighted images. AP-to-pons signal intensity ratios were calculated dividing the values of the AP by those of the pons. The measurements were performed using MR images acquired at four different time points including baseline (prior to any gadodiamide injection), minimum post-injection time delay, maximum post-injection time delay, and last available MR scans. Normalized ratios (i.e. ratios divided total volume of injected gadodiamide) were also calculated. To assess the difference between ratios, non-parametric Wilcoxon signed-rank test was applied. The correlations were tested with non-parametric Spearman correlation coefficient. A p-value < 0.05 was considered as statistically significant. A statistically significant increase of AP signal intensity was found by comparing the baseline scans with both the minimum time delay (p = 0.003) and maximum time delay scans (p = 0.005). We found significant higher normalized ratios for minimum post-injection time delay with respect to maximum post-injection time delay (p < 0.001). The normalized ratios demonstrated a statistically significant negative correlation with the post-injection time delay (r = - 0.31; p = 0.006). The findings of this study suggest that washout phenomena of retained/deposited gadolinium from the AP are influenced by the total injected volume and post-injection time delay.

Increased T1 Signal Intensity of the Anterior Pituitary Gland on Unenhanced Magnetic Resonance Images After Chronic Exposure to Gadodiamide.

OBJECTIVE: The aim of this study was to assess the signal intensity of the anterior pituitary (AP) gland on unenhanced T1-weighted images in patients with history of serial intravenous injections of gadodiamide and normal renal function. MATERIALS AND METHODS: We included 53 patients who had undergone at least 5 injections of gadodiamide and a control group of 15 subjects who underwent at least 5 brain magnetic resonance imaging without gadolinium-based contrast agents. Using unenhanced sagittal T1-weighted images, values of mean signal intensity of the AP and of the central pons were obtained. Anterior pituitary-to-pons signal intensity ratios were calculated dividing the values of the AP by those of the pons. Then, the ratios were compared between the first and the last magnetic resonance imaging scans for all the subjects. To assess the difference between the first and the last ratios, nonparametric Wilcoxon signed-rank test with Monte Carlo resampling was applied. A P value less than 0.05 was considered as statistically significant. RESULTS: The comparison between the first and the last scan revealed a statistically significant increase of AP-to-pons ratio in the last scan for the gadolinium-exposed group (P < 0.001), whereas nonsignificant results were found for the control group (P = nonsignificant). CONCLUSIONS: We found an increased signal intensity of the AP on unenhanced T1-weighted images in patients with history of serial intravenous injections of gadodiamide and normal renal function, suggesting gadolinium deposition or long-term retention within the AP gland. Our findings need to be confirmed by further histochemical analysis of AP gland tissue samples.