Correlation of MRI T2 mapping sequence with knee pain location in young patients with normal standard MRI

'Objective: 'To assess the correlation of T2 mapping abnormalities to knee pain location, in young adults with normal standard knee MRI at 3.0 Tesla. 'Subjects and methods: 'Twenty-three consecutive patients were included prospectively from September 2011 to April 2012. Inclusion criteria were age under 50 years old, knee pain without surgical history, and normal knee MRI at 3.0 Tesla (sagittal T1-weighted images, and sagittal, axial and coronal proton-density-weighted images with saturation of fat signal). Ten asymptomatic volunteers were also included as a control group. Patients and controls had a cartilage T2 mapping MRI sequence in addition to the standard MRI protocol. Two musculoskeletal radiologists, blinded to the patient/control condition and pain location, independently reviewed the T2 mapping images. T2 values below 40 ms were considered normal. They rated the number of hyaline cartilage lesions and their grade according to an ICRS-like score (inspired by the International Cartilage Research Society score) in each anatomical compartment (medial and lateral femoro-tibial and anterior patello-femoral joints). In addition, the T2 value of the largest lesion was measured. Patient’s pain location was classified in the following categories: anterior, lateral, medial and global. T2 mapping findings were compared to pain location, and retrospectively to the initial standard sequences. Sensitivity and specificity were calculated for MRI with T2 mapping according to pain location for each reader. Kappa coefficient was calculated for inter-reader agreement. We used variance analysis in a linear regression to compare T2 values and ICRS-like classification in each compartment. 'Results: 'Sensitivity of MRI with T2 mapping, according to the symptomatic compartment, was respectively: 78% and 87% for Reader 1 and Reader 2 and specificity was 70% for both readers. Kappa coefficient for T2 mapping abnormalities location and pain location was good, with a calculated value of 0.64. There was no significant correlation between ICRS-like classification and T2 values of lesions (p = 0.18). 'Conclusion: 'Our results suggest that T2 mapping is an interesting MRI sequence for the exploration of young patients knee pain in case of normal MRI with a standard protocol, with a good correlation between pain location and focal prolongations of the cartilage T2 relaxation time

Classifying late-onset dementia with MRI: Is arteriosclerotic brain degeneration the most common cause of Alzheimer′s syndrome?

Marie Cécile Henry-Feugeas1, Fannie Onen2, Elisabeth Schouman Claeys11Department of Radiology, 2Department of Geriatrics, Bichat-Claude Bernard University Hospital, AP-HP, Paris, FranceAbstract: Our aim was to use early magnetic resonance imaging (MRI) to investigate the causes of cognitive decline in elderly people with mild cognitive impairment (MCI). Baseline structural and flow quantification MR sequences, and clinical and neuropsychological follow-up for at least two years, were performed on 62 elderly subjects with MCI. Of these subjects, 17 progressed to dementia, and 15 of these progressed to dementia of the Alzheimer type (DAT). Conversion to clinically diagnosed DAT was related to six distinct MR profiles, including one profile suggesting severe AD (20% of these converters) and five profiles suggesting severe cerebrovascular dysfunction. Two profiles suggested arteriosclerotic brain degeneration, one profile suggested severe venous windkessel dysfunction, and two suggested marked cerebral hypoperfusion associated with very low craniospinal compliance or marked brain atrophy. As compared with vascular MR type converters, AD MR type converters showed high executive and mobility predementia performances. Severe whole anteromesial temporal atrophy and predominantly left brain atrophy on visual MR analysis was only observed in AD MR type converters. In conclusion, these observations enhance the pathogenic complexity of the Alzheimer syndrome, and suggest that the role of arteriosclerotic brain degeneration in late life dementia is underestimated.Keywords: Alzheimer’s disease, mild cognitive impairment, dementia, MRI, phase contrast, atherosclerosi

Assessment of normal values of fractional anisotropy and mean diffusivity of mobile lumbar spine roots by diffuson tensor MRI: comparison between 1.5 and 3T.

Purpose: To assess the normal values of fractional anisotropy (FA) and mean diffusivity (MD) of L4, L5 and S1 nerve roots using diffusion tensor imaging (DTI) in healthy volunteers. Materials and methods: 37 subjects without previous history of lumbalgia or radiculalgia were prospectively examined: 27 at 1.5T and 10 at 3T MRI. The protocol included standard anatomical sequences and a DTI acquisition. Nerve root fibers were semi automatically extracted from DTI tractography. FA and MD values were measured at 4 key portions along each L4, L5 and S1 nerve roots. Results: At 1.5T MRI, FA and MD were 0.221 ± 0.011 and 460.9 ± 35.5 mm2.s-1 respectively; at 3T MRI, FA and MD were 0.216 ± 0.01 and 480.1 ± 36.1 mm2.s-1 respectively, which may be considered as normal values for mobile lumbar spine nerve roots, independently of intersomatic space level (p = 0.06) and nerve root portion (p = 0.08) or magnetic field (p = 0.06). Conclusion: Normal FA and MD values can be measured along lumbar mobile spine nerve roots in healthy subjects. These values were not dependent on intersomatic space level, side or anatomical portion of the nerve root or magnetic field

Magnetic resonance angiography of intravascular endoprostheses: Investigation of three devices

Purpose To assess the value of magnetic resonance angiography (MRA) in the evaluation of vascular patency after intravascular endoprosthesis placement. Methods Three different metallic stents (Wallstent, Strecker, Palmaz) were studied in vitro, and in vivo in six patients with spin-echo (SE) and gradient-echo (GRE) MR imaging. Time-of-flight, two-dimensional (2D) gadolinium-enhanced MRA was performed with GRE and flow-compensation technique, and reconstructed with a maximum-intensity projection (MIP) algorithm. MRA was compared to digital angiograms. Results In vitro studies demonstrated that the signal intensity (SI) within the stent differed according to the device employed, the lowest SI being observed within the Palmaz stent (p = .001). There was no difference in SI or apparent diameter of the stent according to the sequence (SE vs GRE) or length of echo time (TE). In patients, the endoprostheses recorded as a well-defined area of signal void or drop-out (p = 0.004), whereas vessels above and below the stent displayed high signal intensities. Conclusion MRA does not seem as yet to be well suited for evaluating vascular patency after endoprosthesis placement, even if the Strecker and Wallstent endoprostheses provide fewer artifacts than the Palmaz stent. © 1995, Springer-Verlag New York Inc. All rights reserved.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Clinical relevance of diffusion tensor imaging parameters in lumbar disco-radicular conflict

Purpose: To measure the fractional anisotropy (FA) and the mean diffusivity (MD) values of L4, L5 and S1 nerve roots using diffusion tensor imaging (DTI) and to correlate them with four different clinical patterns. Patients and methods: Fifty-six human participants were prospectively included and divided between four groups: healthy subjects, patients with clinical symptomatic nerve root pain with and without anatomical discoradicular conflict and patients with incidental anatomical discoradicular conflict seen on magnetic resonance imaging (MRI). MRI protocol included anatomical sequences (sagittal T1- and T2-weighted, axial T2-weighted) and a 25 directions DTI sequence. FA and MD values were measured in consensus by two readers and compared between the four groups. Results: Mean FA and MD values were significantly different for patients with clinically symptomatic nerve root pain (n = 27) both with (n = 16) (FA = 0.187 ± 0.015; MD = 510 ± 40) and without (n = 11) (FA = 0.193 ± 0.011; MD = 490 ± 30.5) anatomical discoradicular conflict compared to healthy subjects (n = 29) (FA = 0.221 ± 0.011; MD = 460.9 ± 35.5) including 2 subjects withincidental anatomical discoradicular conflict (FA = 0.211 ± 0.013; MD = 450.8 ± 41.2) on MRI(P = 0.003).Conclusion: Measurement of FA and MD values of L4, L5 and S1 nerve roots using DTI could beuseful in lumbar nerve root pain assessment. Further studies with different image processingmethods are needed. © 2013 Éditions françaises de radiologie. Published by Elsevier Masson SAS. All rights reserved