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Background— There is considerable heterogeneity in the myocardial substrate of patients undergoing cardiac resynchronization therapy (CRT), in particular in the etiology of heart failure and in the location of conduction block within the heart. This may account for variability in response to CRT. New approaches, including endocardial and multisite left ventricular (LV) stimulation, may improve CRT response. We sought to evaluate these approaches using noncontact mapping to understand the underlying mechanisms. Methods and Results— Ten patients (8 men and 2 women; mean [SD] age 63 [12] years; LV ejection fraction 246%; QRS duration 161 [24] ms) fulfilling conventional CRT criteria underwent an electrophysiological study, with assessment of acute hemodynamic response to conventional CRT as well as LV endocardial and multisite pacing. LV activation pattern was assessed using noncontact mapping. LV endocardial pacing gave a superior acute hemodynamic response compared with conventional CRT (26% versus 37% increase in LV dP/dt max , respectively; P P =0.08). The majority (71%) of patients with nonischemic heart failure etiology or functional block responded to conventional CRT, whereas those with myocardial scar or absence of functional block often required endocardial or multisite pacing to achieve CRT response. Conclusions— Endocardial or multisite pacing may be required in certain subsets of patients undergoing CRT. Patients with ischemic cardiomyopathy and those with narrower QRS, in particular, may stand to benefit.

International audience; Purpose: To assess a simplified scoring method (Simplified Rheumatoid Arthritis Magnetic Resonance Imaging Score [SAMIS]) developed to shorten interpretation time, while retaining both correlation with Rheumatoid Arthritis Magnetic Resonance Imaging Score (RAMRIS) and same or better intra- and interreader reliability.Materials and methods: Ethics board approval and written patient consent were obtained. The study was HIPAA compliant. Thirty-eight patients with rheumatoid arthritis and 20 patients with no or early unclassified arthritis underwent magnetic resonance imaging of both wrists and hands. RAMRIS was used to evaluate erosions (scale, 0-10), edema (scale, 0-3), and synovitis (scale, 0-3). SAMIS assessed only one hand and was based on the radiographic Simple Erosion Narrowing Score, thus reducing the number of study areas from 116 to 36. Erosions were scored with a scale from 1 to 10. Edema and synovitis were, respectively, scored with scales from 0 to 1 and 0 to 2. SAMIS correlation with RAMRIS was tested by using the Spearman test. Last, the intra- and interobserver reproducibility of both scores were calculated.Results: SAMIS was closely correlated with RAMRIS for the entire series (r = 0.91, 0.79, and 0.94, respectively, for erosion, edema, and synovitis), as well as in patients with rheumatoid arthritis (r = 0.93, 0.81, and 0.92) and those with no or unclassified arthritis (r = 0.83, 0.73, and 0.94). The time needed to assess examination results with RAMRIS ranged from 5 to 20 minutes (13 minutes +/- 3.90 [standard deviation]), whereas it ranged from 2 to 7 minutes (5 minutes +/- 1.45) with SAMIS. For each of the three features (erosion, edema, and synovitis), intraobserver agreement (RAMRIS: kappa = 0.67, 0.94, 0.81, respectively; SAMIS: kappa = 0.66, 1.0, 0.91) and interobserver agreement (RAMRIS: kappa = 0.61, 0.58, 0.74, respectively; SAMIS: kappa = 0.59, 0.81, 0.81) were good to excellent.Conclusion: This simplified reproducible scoring scheme could be used to monitor joint damage in rheumatoid arthritis. (c) RSNA, 2010.

International audience; Perfusion magnetic resonance imaging (MRI) offers relative safety (no ionizing radiation), high spatial/temporal resolution, multi-orientation imaging capability, and relative low cost when compared with sophisticated techniques, such as positron emission tomography (PET). Several methods have been recently proposed to image perfusion. Some techniques mimic conventional nuclear medicine principles, but use radioactively inert tracers. Other approaches directly use blood as an endogenous natural tracer. Such methods are totally noninvasive, and offer original insights, for instance by monitoring variations in blood oxygenation in human brain cortex during activation tasks. These methods are presented and compared. Emphasis is given on advantages and drawbacks, and potential clinical applications.

International audience

International audience; In this study, we investigated the prognostic value of MRI contrast enhancement (CE) at the time of histological diagnosis specifically in a selected population of WHO grade II gliomas. We reviewed 927 histologically proven WHO grade II gliomas for which contrast-enhanced MR images were available at the time of histological diagnosis. CE patterns were classified into three categories: "patchy and faint," "nodular-like," and "ring-like." CE progression over time was recorded before oncological treatment on successive MR images, when available. CE was present in 143 cases (15.9%), with 93 patchy and faint, 50 nodular-like, and no ring-like patterns. CE areas were time progressive before oncological treatment in 35 of the 56 available cases (62.5%). Regardless of its pattern, the presence of CE was not significantly associated with a worsened prognosis (p = 0.415) by univariate analysis. Only the nodular-like pattern of CE (p < 0.01) and the time-progressive CE (p < 0.001) in the available subgroup proved to be statistically associated with survival since first oncological treatment. The present results show the necessity, in cases of WHO grade II gliomas, to study CE at the time of histological diagnosis and, whenever possible, to follow its progression over time before oncological treatment. Nodular-like CE and time-progressive CE are associated with a worsened prognosis, both suggesting malignant transformation, even though histopathological examination cannot initially disclose signs of malignancy in those areas.

International audience; PURPOSE: To analyze the relationship between late contrast enhancement (LCE) and the interstitial distribution volume (V(In)) of gadolinium (Gd) tracers in the myocardial infarction (MI) areas supplied by chronically occluded arteries from patients. In animal experimental models, LCE has already been shown to correspond to an enhanced V(In) of Gd tracers and thus, to a decrease in the amount of intact cells. MATERIALS AND METHODS: A multicompartmental analysis was applied to serial MRI images encompassing both infarct and remote areas and recorded with a conventional two-dimensional (2D) segmented inversion-recovery gradient-echo (IR-GRE) sequence during a 15-minute period following Gd-diethylenetriamine pentaacetic acid (Gd-DTPA) injection in 12 patients with Q-wave MI supplied by chronically occluded coronary arteries. RESULTS: V(In) from infarct tissue was: 1) higher than V(In) from remote areas (in % of myocardial volume: 74 +/- 16% vs. 20 +/- 7%, P < 0.001); and 2) correlated with the quantification of LCE between infarct and noninfarct areas at the 15th minute (R(2) = 0.63, P = 0.002). However, the difference in V(In) between infarct and remote myocardium was a much better correlate of this quantified LCE (R(2) = 0.85, P < 0.001). CONCLUSION: Detection of LCE in the MI territories supplied by chronically occluded arteries relates to the difference in the V(In) of tracers between the infarct and the noninfarct areas.

International audience; MR Urography (MRU) provides both morphologic and functional information without radiation exposure. It enables the assessment of split renal function, excretion, and quantification of obstruction. MRU is thus complementary to ultrasonography in the assessment of pre- and post-natal obstructive uropathies in children. If available, MRU should be definitely preferred to intravenous urography.

Objective— The association of inflammatory cells and neovessels in atherosclerosis is considered a histological hallmark of high-risk active lesions. Therefore, the development and validation of noninvasive imaging techniques that allow for the detection of inflammation and neoangiogenesis in atherosclerosis would be of major clinical interest. Our aim was to test 2 techniques, black blood dynamic contrast enhanced MRI (DCE-MRI) and 18-fluorine-fluorodeoxyglucose (18F-FDG) PET, to quantify inflammation expressed as plaque neovessels content in a rabbit model of atherosclerosis. Methods and Results— Atherosclerotic plaques were induced in the aorta of 10 rabbits by a combination of 2 endothelial abrasions and 4 months hyperlipidemic diet. Six rabbits underwent MRI during the injection of Gd-DTPA, whereas 4 rabbits were imaged after injection of 18F-FDG with PET. We found a positive correlation between neovessels count in atherosclerotic plaques and (1) Gd-DTPA uptake parameters evaluated by DCE-MRI ( r =0.89, P =0.016) and (2) 18F-FDG uptake evaluated by PET ( r =0.5, P =0.103 after clustered robust, Huber-White, standard errors analysis). Conclusion— DCE-MRI and 18F-FDG PET may allow for the evaluation of inflammation in atherosclerotic plaques of rabbits. These noninvasive imaging modalities could be proposed as clinical tools in the evaluation of lesion prognosis and monitoring of anti–angiogenic therapies.

International audience; PURPOSE: To test whether B-22956/1, a novel intravascular contrast agent with a high affinity to serum albumin (Bracco Imaging SpA.), allowed quantifying neovessel and macrophage density in atherosclerotic plaques of rabbits using MRI. MATERIALS AND METHODS: A T1-weighted MRI of the aorta was acquired in 10 rabbits (7 atherosclerotic and 3 control rabbits) before and up to 2 h after intravenous injection of 100 mumol/kg of Gd-DTPA or 75 mumol/kg of B-22956/1. Plaque enhancement was measured at different time points. Immunohistochemistry was performed using anti-CD 31 antibodies and anti-RAM 11 antibodies to correlate to neovessel and macrophage density, respectively. RESULTS: MRI showed a significant plaque enhancement 2 h after B-22956/1 versus Gd-DTPA in the atherosclerotic group (39.75% versus 9.5%; P < 0.0001. Early atherosclerotic plaques (n = 146) enhancement positively correlates with neovessel density on corresponding histological sections (r = 0.42; P < 0.01). Enhancement of atherosclerotic plaques 2 h after injection of B-22956/1 correlated with macrophage density (r = 0.71; P < 0.01). CONCLUSION: Enhancement of atherosclerotic plaques with MRI correlated with neovessel density at early time points after the injection of B-22956/1 and with macrophage density, at later time points. Hence, B-22956/1-enhanced MRI represents a promising imaging technique for the identification of "high-risk" plaques.

International audience; PURPOSE: To present the imaging and perfusion data obtained in nine patients with pilocytic astrocytomas (PA) and to discuss the original functional issues of this technique. METHOD: Nine patients with pathologically proven PA underwent conventional and perfusion MR imaging. Various areas of relative cerebral blood volume (rCBV) within the tumors were obtained. The maximum rCBV ratios were identified and considered as representative of the tumor. The results were compared with the pathological findings. RESULTS: In all patients, rCBV was

Purpose To prospectively assess the use of cardiac MRI with delayed contrast enhancement (DCE) for identifying patients with active myocarditis among those presenting with acute coronary syndrome (ACS) but no coronary stenosis. Materials and Methods A total of 27 consecutive patients (age = 45 ± 17 years; 14 male) presenting with ACS (chest pain, positive troponin-I) and no coronary stenosis, underwent cardiac MRI 9 ± 7 days after pain onset and 8 ± 5 months later (N = 19). Steady-state free-precession pulse (SSFP) sequence was applied for the assessment of myocardial function and both inversion-recovery (IR) and SSFP sequences were used for analyzing the topography and extent of DCE areas. Rest sestamibi-gated-single photon emission CT (SPECT) was also systematically performed. Results Subepicardial DCE pattern typical of acute myocarditis was documented in 12 patients (44%). Ischemic DCE pattern (transmural or subendocardial focal DCE) was documented in 12 of the 15 remaining patients (44%). Patients with subepicardial DCE had: higher C-reactive protein (CRP) levels (38 ± 32 vs. 14 ± 24 mg/mL; P = 0.04), lower Framingham cardiovascular risk (3 ± 3% vs. 9 ± 5%; P < 0.001), lower incidence of perfusion SPECT defects (17% vs. 73%; P = 0.01), higher left ventricular (LV) end-diastolic volume (77 ± 16 vs. 64 ± 10 mL/m2; P = 0.02), and higher regression of DCE areas at follow-up (−65 ± 17% vs. −18 ± 23%; P = 0.002). Conclusion DCE pattern of active myocarditis can be seen in patients presenting with ACS but no coronary stenosis. J. Magn. Reson. Imaging 2007;25:957–964. © 2007 Wiley-Liss, Inc.

International audience; PURPOSE: To prospectively evaluate accuracy of gadolinium-enhanced three-dimensional (3D) magnetic resonance (MR) angiography with gadodiamide and gadopentetate dimeglumine (0.1 mmol/kg), with intraarterial DSA as reference standard, for imaging abdominal and iliac arterial stenoses. MATERIALS AND METHODS: The study was approved by all institutional review boards; informed consent was obtained from each subject before procedures. Two hundred forty-seven subjects were included; 240 received either contrast agent and were available for safety analysis; 222 were available for accuracy analysis. Enhanced 3D MR angiography and DSA were performed; image data were evaluated in a double-blinded randomized study. Stenoses were classified as not relevant ( or =50%). For detection of main stenosis, accuracy with enhanced 3D MR angiography compared with that with DSA was determined. RESULTS: The difference in accuracy for imaging with gadodiamide and gadopentetate was 3.6%. Noninferiority was inferred because the lower bound of the exact two-sided 95% confidence interval was -10.1 and was above the noninferiority margin (-15%). Accuracy for detection of the main stenosis was low, 56.4% for gadodiamide and 52.8% for gadopentetate group. Subgroup analysis with exclusion of inferior mesenteric artery and internal iliac arteries and the most false-positive stenosis classifications yielded better results: 76.6% and 71.6%, respectively. Sensitivity, specificity, and negative and positive predictive values did not differ substantially between study groups. In the main analysis, values were 44%, 96%, 35%, and 97% for gadodiamide and 44%, 83%, 30%, and 90% for gadopentetate, respectively. In the subgroup analysis, values were 66%, 95%, 61%, and 96% for gadodiamide and 63%, 86%, 58%, and 88% for gadopentetate, respectively. CONCLUSION: Noninferiority of gadodiamide versus gadopentetate was verified based on the primary end point, which was accuracy for detection of the main stenosis with enhanced 3D MR angiography compared with DSA.