Age- and Gender Dependent Liver Fat Content in a Healthy Normal BMI Population as Quantified by Fat-Water Separating DIXON MR Imaging

OBJECTIVES To establish age- and sex-dependent values of magnetic resonance (MR) liver fat-signal fraction (FSF) in healthy volunteers with normal body-mass index (BMI). METHODS 2-point mDIXON sequences (repetition time/echo time, 4.2msec/1.2msec, 3.1msec) at 3.0 Tesla MR were acquired in 80 healthy volunteers with normal BMI (18.2 to 25.7 kg/m2) between 20 and 62 years (10 men/10 women per decade). FSF was measured in 5 liver segments (segment II, III, VI, VII, VIII) based on mean signal intensities in regions of interest placed on mDIXON-based water and fat images. Multivariate general linear models were used to test for significant differences between BMI-corrected FSF among age subgroups. Pearson and Spearman correlations between FSF and several body measures were calculated. RESULTS Mean FSF (%) ± standard deviations significantly differed between women (3.91 ± 1.10) and men (4.69 ± 1.38) and varied with age for women/men (p-value: 0.002/0.027): 3.05 ± 0.49/3.74 ± 0.60 (age group 20-29), 3.75 ± 0.66/4.99 ± 1.30 (30-39), 4.76 ± 1.16/5.25 ± 1.97 (40-49) and 4.09 ± 1.26/4.79 ± 0.93 (50-62). FSF differences among age subgroups were significant for women only (p = 0.003). CONCLUSIONS MR-based liver fat content is higher in men and peaks in the fifth decade for both genders

Hip MRI findings and outcomes following imaging-guided hip injections

OBJECTIVE To determine if MRI findings prior to intra-articular corticosteroid hip infiltration are related to treatment outcomes. METHODS This prospective outcome study with retrospective MRI evaluation includes 100 consecutive patients with MRI within 6 months before a therapeutic intra-articular hip injection. Labrum, bone marrow, acetabular and femoral cartilage abnormalities were assessed by two radiologists blinded to patient outcomes: the proportion reporting "improvement" on the Patient's Global Impression of Change (PGIC) scale at 1 day, 1 week and 1 month follow-up were compared based on MRI findings using χ$^{2}$. The t-test was used to compare pain change scores with MRI abnormalities. RESULTS Patients with a normal labrum in the posterosuperior quadrant were more likely to report PGIC "improvement" at 1 week compared to labral degeneration (p = 0.048). Significant differences in pain change scores were found at all time points for the labral anteroinferior quadrant (p = 0.001, 1 day; p = 0.010, 1 week; p = 0.034, 1 month) with the highest reduction in patients with labral degeneration. Females were 2.80 times more likely to report clinically relevant "improvement" at 1 day (p = .049) and 2.90 times more likely to report clinically relevant "improvement" at 1 month (p = .045). CONCLUSION Cartilage defects and marrow abnormalities were not associated with outcomes. Patients with a normal labrum in the posterosuperior quadrant had better outcomes at 1 week. Patients with labral degeneration of the anteroinferior quadrant had higher levels of pain reduction at all time points. Females were significantly more likely to report PGIC "improvement". ADVANCES IN KNOWLEDGE A significant treatment outcome was observed amongst gender, although there were no significant differences in the MRI findings

Imaging of acute cervical spine trauma: when to obtain which modality

The current knowledge and evidence around the merits of different imaging modalities for the evaluation of cervical spine injuries are reviewed. The National Emergency X-Radiography Use Study, Canadian Cervical Spine rule, and American College of Radiology appropriateness criteria are reviewed and summarized. The advantages and disadvantages of available imaging modalities for selected cervical spine injury patterns are also illuminated to simplify the decision making on when to use which modality

Cross-sectional area measurements versus volumetric assessment of the quadriceps femoris muscle in patients with anterior cruciate ligament reconstructions

OBJECTIVE Our aim was to validate the use of cross-sectional area (CSA) measurements at multiple quadriceps muscle levels for estimating the total muscle volume (TMV), and to define the best correlating measurement level. METHODS Prospective institutional review board (IRB)-approved study with written informed patient consent. Thighs of thirty-four consecutive patients with ACL-reconstructions (men, 22; women, 12) were imaged at 1.5-T using three-dimensional (3D) spoiled dual gradient-echo sequences. CSA was measured at three levels: 15, 20, and 25 cm above the knee joint line. TMV was determined using dedicated volumetry software with semiautomatic segmentation. Pearson's correlation and regression analysis (including standard error of the estimate, SEE) was used to compare CSA and TMV. RESULTS The mean ± standard deviation (SD) for the CSA was 60.6 ± 12.8 cm(2) (range, 35.6-93.4 cm(2)), 71.1 ± 15.1 cm(2) (range, 42.5-108.9 cm(2)) and 74.2 ± 17.1 cm(2) (range, 40.9-115.9 cm(2)) for CSA-15, CSA-20 and CSA-25, respectively. The mean ± SD quadriceps' TMV was 1949 ± 533.7 cm(3) (range, 964.0-3283.0 cm(3)). Pearson correlation coefficient was r = 0.835 (p < 0.01), r = 0.906 (p < 0.01), and r = 0.956 (p < 0.01) for CSA-15, CSA-20 and CSA-25, respectively. Corresponding SEE, expressed as percentage of the TMV, were 15.2 %, 11.6 % and 8.1 %, respectively. CONCLUSION The best correlation coefficient between quadriceps CSA and TMV was found for CSA-25, but its clinical application to estimate the TMV is limited by a relatively large SEE. KEY POINTS • Cross-sectional area was used to estimate QFM size in patients with ACL-reconstruction • A high correlation coefficient exists between quadriceps CSA and volume • Best correlation was seen 25 cm above the knee joint line • A relatively large standard error of the estimate limits CSA application

Reduction of Metal Artifacts in Patients with Total Hip Arthroplasty with Slice-encoding Metal Artifact Correction and View-Angle Tilting MR Imaging

Purpose: To compare the new "warp" sequence (slice-encoding metal artifact correction [SEMAC], view-angle tilting [VAT], and increased bandwidth) for the reduction of both through-plane and in-plane magnetic resonance (MR) artifacts with current optimized MR sequences in patients with total hip arthroplasty (THA). Materials and Methods: The institutional review board issued a waiver for this study. Forty patients with THA were prospectively included. SEMAC, VAT, and increased bandwidth were applied by using the warp turbo-spin-echo sequence at 1.5 T. Coronal short tau inversion-recovery (STIR)-warp and transverse T1-weighted warp (hereafter, T1-warp) images, as well as standard coronal STIR and transverse T1-weighted sequence images optimized with high bandwidth (STIR-hiBW and T1-hiBW), were acquired. Fifteen additional patients were examined to compare the T1-warp and T1-hiBW sequence with an identical matrix size. Signal void was quantified. Qualitative criteria (distinction of anatomic structures, blurring, and noise) were assessed on a five-point scale (1, no artifacts; 5, not visible due to severe artifacts) by two readers. Abnormal imaging findings were recorded. Quantitative data were analyzed with a t test and qualitative data with a Wilcoxon signed rank test. Results: Signal void around the acetabular component was smaller for STIR-warp than STIR-hiBW images (21.6 cm(2) vs 42.4 cm(2); P = .0001), and for T1-warp than T1-hiBW images (17.6 cm(2) vs 20.2 cm(2); P = .0001). Anatomic distinction was better on STIR-warp compared with STIR-hiBW images (1.9-2.8 vs 3.6-4.6; P = .0001), and on T1-warp compared with T1-hiBW images (1.3-2.8 vs 1.8-3.2; P < .002). Distortion, blurring, and noise were lower with warp sequences than with the standard sequences (P = .0001). Almost half of the abnormal imaging findings were missed on STIR-hiBW compared with STIR-warp images (55 vs 105 findings; P = .0001), while T1-hiBW was similar to T1-warp imaging (50 vs 55 findings; P = .06). Conclusion: STIR-warp and T1-warp sequences were significantly better according to quantitative and qualitative image criteria, but a clinically relevant artifact reduction was only present for STIR images. © RSNA, 2012

PROPELLER technique to improve image quality of MRI of the shoulder

The PROPELLER technique for MRI of the shoulder reduces the number of sequences with diagnostic impairment as a result of motion artifacts and increases image quality compared with standard TSE sequences. PROPELLER sequences increase the acquisition time

Ligaments of the Lisfranc joint in MRI: 3D-SPACE (sampling perfection with application optimized contrasts using different flip-angle evolution) sequence compared to three orthogonal proton-density fat-saturated (PD fs) sequences

PURPOSE: To compare the detection rate and visibility of the ligaments in the Lisfranc joint with a single 3D (-SPACE) MR sequence and three orthogonal PD fat-saturated sequences. MATERIALS AND METHODS: Thirty-one asymptomatic feet and 15 patients with posttraumatic pain in the Lisfranc joint were evaluated with a 3D-SPACE-sequence (0.5 mm section thickness, acquisition time 10:22 min, secondary reformations) and three orthogonal PD fs sequences (2 mm section thickness, 9:20 min). The Lisfranc-ligament, the dorsal and plantar tarsometatarsal ligaments (TMT), the dorsal, interosseous, and plantar intermetatarsal ligaments (IMT) (24 ligaments for each foot) were assessed. RESULTS: In asymptomatic feet, 692 ligaments were detected with the SPACE sequence, thereof 90.6 % exhibited normal signal, and most (96.9 %) were completely visible on one single image. A total of 659 ligaments were detected with the PD fs sequence, thereof 86.6 % yielded normal signal, and 28.5 % were completely visible on one single image. In patients, 327 ligaments were detected with SPACE, thereof 50.6 % appeared completely visible with high signal. On PD fs, 308 ligaments were detected, 42.2 % of the ligaments had high signals. CONCLUSIONS: The ligaments of the Lisfranc joint are better detected with a single 3D-SPACE sequence and secondary reformations than with three orthogonal PD fs sequences

STIR sequence with increased receiver bandwidth of the inversion pulse for reduction of metallic artifacts

OBJECTIVE: The purpose of this study was to evaluate a STIR sequence with an optimized inversion pulse that entails use of increased receiver bandwidth for metal artifact reduction. CONCLUSION: Image distortion, artifacts, insufficient fat suppression, and detection of relevant findings improved with the STIR optimized inversion pulse, which was associated with significant artifact reduction

Shoulder muscle volume and fat content in healthy adult volunteers : quantification with DIXON MRI to determine the influence of demographics and handedness

Erworben im Rahmen der Schweizer Nationallizenzen (http://www.nationallizenzen.ch)Objective: We aimed to provide mean values for fat-fraction and volume for full-length bilateral rotator cuff and deltoid muscles in asymptomatic adults selected on the basis of their good musculoskeletal and systemic health, and to understand the influence of gender, age, and arm dominance. Materials and methods: Seventy-six volunteers aged 20 to 60 years who were screened for normal BMI and high general health were included in the study. MRI was performed at 3 Tesla using three-point DIXON sequences. Volume and fat-signal fraction of the rotator cuff muscles and the deltoid muscle were determined with semi-automated segmentation of entire muscle lengths. Differences according to age, gender, and handedness per muscle were evaluated. Results: Fat-signal fractions were comparable between genders (mean ± 2 SD, 95% CI, women 7.0 ± 3.0; 6.8-7.2%, men 6.8 ± 2.7; 6.7-7.0%) but did not show convincing changes with age. Higher shoulder muscle volume and lower fat-signal fraction in the dominant arm were shown for teres minor and deltoid (p < 0.01) with similar trends shown for the other rotator cuff muscles. Conclusions: Bilateral fat-signal fractions and volumes based on entire length shoulder muscles in asymptomatic 20-60 year old adults may provide reference for clinicians. Differences shown according to arm dominance should be considered and may rationalize the need for bilateral imaging in determining appropriate management