Gadolinium deposition in normal brain and bone tissue occurs with macrocyclic and linear protein interacting agents in patients with normal renal function. Deposition of Gd in cortical bone occurs at much higher levels compared with brain tissue and shows a notable correlation between the two. Thus, the bone may serve as a surrogate to estimate brain deposition if brain Gd were to become a useful clinical or research marker.

Background and Purpose-Although studies have attempted to differentiate intracranial vascular disease using vessel wall magnetic resonance imaging (VWI), none have incorporated multicontrast imaging. This study uses T1-and T2-weighted VWI to differentiate intracranial vasculopathies. Methods-We retrospectively reviewed patients with clinically defined intracranial vasculopathies causing luminal stenosis/ irregularity who underwent VWI studies. Two blinded experts evaluated T1 precontrast and postcontrast and T2-weighted VWI characteristics, including the pattern of wall thickening; presence, pattern, and intensity of postcontrast enhancement; and T2 signal characteristics. Results-Twenty-one cases of atherosclerosis (intracranial atherosclerotic disease [ICAD]), 4 of reversible cerebral vasoconstriction syndrome, and 4 of vasculitis were identified, with a total of 118 stenotic lesions (81 ICAD, 22 reversible cerebral vasoconstriction syndrome, and 15 vasculitic lesions). There was substantial to excellent inter-reader agreement for the assessment of lesional T2 hyperintensity (κ=0.80), pattern of wall thickening (κ=0.87), presence (κ=0.90), pattern (κ=0.73), and intensity (κ=0.77) of enhancement. ICAD lesions were significantly more likely to have eccentric wall involvement (90.1%) than reversible cerebral vasoconstriction syndrome (8.2%; P<0.001) and vasculitic lesions (6.7%; P<0.001) and were also more likely to have T2 hyperintensity present than the other 2 vasculopathies (79% versus 0%; P<0.001). There were also significant differences in the presence, intensity, and pattern of enhancement between all lesion types. Combining T1 and T2 VWI increased the sensitivity of VWI in differentiating ICAD from other vasculopathies from 90.1% to 96.3%. on VWI has been described and shown to correspond to the fibrous cap on histology. 15 In contrast, the T2 hypointense outer component of the plaque corresponds to areas rich in foamy macrophages and proteoglycans, and lipid rich necrotic core on T2-weighted VWI. 16 To our knowledge, no reports have used T2-weighted high-resolution VWI and multicontrast protocols as a technique to discriminate between vasculopathies. In this study, we evaluated the imaging findings of different vasculopathies on T2 and T1 pre and postcontrast imaging to identify unique features and test their ability to correctly identify disease and develop an algorithm to differentiate intracranial vasculopathies. We also investigate the additional benefit of using multicontrast VWI over pre and postcontrast T1 alone to differentiate disease. Conclusions-Multicontrast Methods Patient Population and Clinical DiagnosisAfter institutional review board approval, we reviewed consecutive patients from January 2011 to April 2014 with suspicion of intracranial vasculopathy who had VWI and, on luminal imaging, had appreciable intracranial arterial stenosis or irregularity. There were a total of 68 patients, who had 77 high-resolution VWI studies performed. Patients were further stratified into diagnostic vascu...

A Simultaneous Non-contrast Angiography and intraPlaque hemorrhage (SNAP) MR imaging technique is proposed to detect both luminal stenosis and hemorrhage in atherosclerosis patients in a single scan. 13 patients with diagnosed carotid atherosclerotic plaque were recruited after informed consent. All scans were performed on a 3T MR imaging system with SNAP, 2D time-of-flight (TOF) and magnetization-prepared 3D rapid acquisition gradient echo (MP-RAGE) sequences. The SNAP sequence utilized a phase sensitive acquisition, and was designed to provide positive signals corresponding to intraplaque hemorrhage (IPH) and negative signals corresponding to lumen. SNAP images were compared to TOF images to evaluate lumen size measurements using linear mixed models and the intraclass correlation coefficient (ICC). IPH identification accuracy was evaluated by comparing to MP-RAGE images using Cohen’s Kappa. Diagnostic quality SNAP images were generated from all subjects. Quantitatively, the lumen size measurements by SNAP were strongly correlated (ICC=0.96, p<0.001) with those measured by TOF. For IPH detection, strong agreement (κ=0.82, p<0.001) was also identified between SNAP and MP-RAGE images. In conclusion, a Simultaneous Non-contrast Angiography and intraPlaque hemorrhage (SNAP) imaging technique was proposed and shows great promise for imaging both lumen size and carotid intraplaque hemorrhage with a single scan.

Objectives The purpose of this study was to determine the immediate and long-term effects of intraplaque hemorrhage (IPH) on plaque progression in the carotid artery. Background Previous studies have associated IPH in the carotid artery with more rapid plaque progression. However, the time course and long-term effect remain unknown. Carotid magnetic resonance imaging (MRI) is a non-invasive imaging technique that has been validated with histology for the accurate in vivo detection of IPH and measurement of plaque burden. Methods Asymptomatic subjects with 50–79% carotid stenosis underwent carotid MRI at baseline and then serially every 18 months for a total of 54 months. Subjects with IPH present in at least one carotid artery at 54 months were selected. Subsequently, presence/absence of IPH and wall volume were determined independently in all time points for both sides. A piecewise progression curve was fit using linear mixed model to compare progression rates defined as annualized changes in wall volume between periods defined by their relationship to IPH development. Results From 14 patients that showed IPH at 54 months, 12 arteries were found to have developed IPH during the study period. The progression rates were −20.5±13.1, 20.5±13.6 and 16.5±10.8 mm3/year before, during and after IPH development, respectively. The progression rate during IPH development tended to be higher than the period before (p=0.080), but comparable to the period after (p=0.845). The progression rate in the combined period during/after IPH development was 18.3±6.5 mm3/year, which indicated significant progression (p=0.008 compared to a slope of 0) and was higher than the period before IPH development (p=0.018). No coincident ischemic events were noted for new IPH. Conclusions The development of IPH posed an immediate and long-term promoting effect on plaque progression. IPH appears to alter the biology and natural history of carotid atherosclerosis. Early identification of patients with IPH may prove invaluable in optimizing management to minimize future sequelae.

BACKGROUND AND PURPOSE:Compressed sensing-sensitivity encoding is a promising MR imaging acceleration technique. This study compares the image quality of compressed sensing-sensitivity encoding accelerated imaging with conventional MR imaging sequences. MATERIALS AND METHODS:Patients with known, treated, or suspected brain tumors underwent compressed sensing-sensitivity encoding accelerated 3D T1-echo-spoiled gradient echo or 3D T2-FLAIR sequences in addition to the corresponding conventional acquisition as part of their clinical brain MR imaging. Two neuroradiologists blinded to sequence and patient information independently evaluated both the accelerated and corresponding conventional acquisitions. The sequences were evaluated on 4-or 5-point Likert scales for overall image quality, SNR, extent/severity of artifacts, and gray-white junction and lesion boundary sharpness. SNR and contrast-to-noise ratio values were compared. RESULTS:Sixty-six patients were included in the study. For T1-echo-spoiled gradient echo, image quality in all 5 metrics was slightly better for compressed sensing-sensitivity encoding than conventional images on average, though it was not statistically significant, and the lower bounds of the 95% confidence intervals indicated that compressed sensing-sensitivity encoding image quality was within 10% of conventional imaging. For T2-FLAIR, image quality of the compressed sensing-sensitivity encoding images was within 10% of the conventional images on average for 3 of 5 metrics. The compressed sensing-sensitivity encoding images had somewhat more artifacts (P ϭ .068) and less gray-white matter sharpness (P ϭ .36) than the conventional images, though neither difference was significant. There was no significant difference in the SNR and contrast-to-noise ratio. There was 25% and 35% scan-time reduction with compressed sensing-sensitivity encoding for FLAIR and echo-spoiled gradient echo sequences, respectively. CONCLUSIONS:Compressed sensing-sensitivity encoding accelerated 3D T1-echo-spoiled gradient echo and T2-FLAIR sequences of the brain show image quality similar to that of standard acquisitions with reduced scan time. Compressed sensing-sensitivity encoding may reduce scan time without sacrificing image quality. ABBREVIATIONS:CNR ϭ contrast-to-noise ratio; CS ϭ compressed sensing; SENSE ϭ sensitivity encoding; SPGR ϭ echo-spoiled gradient echo

MRI performance is superior in women with PH compared with women with GFH. Screening MRI warrants consideration as an adjunct to mammography in women with a PH of breast cancer.

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