Epicardial Fat Volume and Aortic Stiffness in Healthy Individuals: A Quantitative Cardiac Magnetic Resonance Study.

PURPOSE: To determine epicardial fat volume (EFV) and aortic stiffness (assessed by aortic pulse wave velocity (PWV)) in healthy individuals, and to investigate the relationship of these parameters, and their association with body mass index (BMI) and age. MATERIALS AND METHODS: 58 subjects (29 men, mean age 44.7 ± 13.9 years[y]) underwent a CMR exam at 1.5 Tesla. A 2 D velocity-encoded CMR scan was acquired to determine PWV. The EFV was measured based on a 3 D-mDixon sequence. Group comparisons were made between younger (age < 45y; n = 30; mean age 33.4 ±â€Š6.6y) and older (> 45y; n = 28; 56.7 ± 8.4y) subjects and between subjects with a BMI < 25 kg/m(2) (n = 28; BMI 21.9 ±â€Š2.5 kg/m(2)) and a BMI > 25 kg/m(2) (n = 30; 28.7 ±â€Š4.0 kg/m(2)). Associations between the determined parameters were assessed by analyses of covariance (ANCOVAs). RESULTS: The mean values of PWV and EFV (normalized to body surface area) were 6.9 ±â€Š1.9 m/s and 44.2 ±â€Š25.0 ml/m(2), respectively. The PWV and EFV were significantly higher in the older group (PWV = 7.9 ±â€Š2.0 m/s vs. 6.0 ±â€Š1.2 m/s; EFV = 54.7 ml/m² vs. 34.5 ml/m²; p < 0.01, each), with no significant differences in BMI or sex. In the overweighted group the EFV was significantly higher than in subjects with a BMI < 25 kg/m² (EFV = 56.1 ±â€Š27.1 ml/m(2) vs. 31.5 ±â€Š14.6 ml/m(2); p < 0.01) but without a significant difference in PWV. ANCOVA revealed a significant correlation between EFV and PWV, also after adjustment for age (p = 0.025). CONCLUSION: An association was found between age and EFV as well as PWV. EFV and PWV were related to each other also after adjustment for age. The metabolic and pro-inflammatory activity found with increased epicardial fat volume may promote the development of atherosclerosis and aortic stiffness. CMR may be valuable for future studies investigating the relationship between EFV and PWV in patients with increased cardiovascular risk. KEY POINTS: • EFV and PWV can be assessed in a single CMR exam.• EFV and aortic stiffness are both associated with cardiovascular risk.• EFV correlates with aortic stiffness, possibly due to similar pro-inflammatory mechanisms. Citation Format: • Homsi R, Thomas D, Gieseke J et al. Epicardial Fat Volume and Aortic Stiffness in Healthy Individuals: A Quantitative Cardiac Magnetic Resonance Study. Fortschr Röntgenstr 2016; 188: 853 - 858.

Three-Dimensional Isotropic Fat-Suppressed Proton Density-Weighted MRI at 3 Tesla Using a T/R-Coil Can Replace Multiple Plane Two-Dimensional Sequences in Knee Imaging.

PURPOSE: To evaluate whether a 3 D proton density-weighted fat-suppressed sequence (PDwFS) of the knee is able to replace multiplanar 2D-PDwFS. MATERIALS AND METHODS: 52 patients (26 men, mean age: 41.9 ±â€Š14.5years) underwent magnetic resonance imaging (MRI) of the knee at 3.0 Tesla using a T/R-coil. The imaging protocol included 3 planes of 2D-PDwFS (acquisition time (AT): 6:40 min; voxel sizes: 0.40 - 0.63 × 0.44 - 0.89 × 3mm³) and a 3D-PDwFS (AT: 6:31 min; voxel size: 0.63 × 0.68 × 0.63mm³). Homogeneity of fat suppression (HFS), artifacts, and image sharpness (IS) were evaluated on a 5-point scale (5[excellent] - 1[non-diagnostic]). The sum served as a measure for the overall image quality (OIQ). Contrast ratios (CR) compared to popliteal muscle were calculated for the meniscus (MEN), anterior (ACL) and posterior cruciate ligaments (PCL). In 13 patients who underwent arthroscopic knee surgery, two radiologists evaluated the presence of meniscal, ligamental and cartilage lesions to estimate the sensitivity and specificity of lesion detection. RESULTS: The CR was higher in the ACL, PCL and MEN in 3D- PDwFS compared to 2D-PDwFS (p < 0.01 for ACL and PCL; p = 0.07 for MEN). Compared to 2 D images, the OIQ was rated higher in 3D-PDwFS images (p < 0.01) due to fewer artifacts and HFS despite the lower IS (p < 0.01). The sensitivity and specificity of lesion detection in 3D- and 2D-PDwFS were similar. CONCLUSION: Compared to standard multiplanar 2D-PDwFS knee imaging, isotropic high spatial resolution 3D-PDwFS of the knee at 3.0 T can be acquired with high image quality in a reasonable scan time. Multiplanar reformations in arbitrary planes may serve as an additional benefit of 3D-PDwFS. KEY POINTS: • 3D-PDwFS of the knee is acquired with high image quality• 3D-PDwFS can be achieved in only one measurement with a reasonable scan time• 3D-PDwFS with the advantage of multiplanar reformation may replace 2D-PD-weighted knee MRI Citation Format: • Homsi R, Gieseke J, Luetkens JA et al. Three-Dimensional Isotropic Fat-Suppressed Proton Density-Weighted MRI at 3 Tesla Using a T/R-Coil Can Replace Multiple Plane Two-Dimensional Sequences in Knee Imaging. Fortschr Röntgenstr 2016; 188: 949 - 956.

Diffusion-weighted MR neurography of the brachial and lumbosacral plexus: 3.0 T versus 1.5 T imaging.

PURPOSE: To compare intraindividually the nerve conspicuity of the brachial and lumbosacral plexus on diffusion-weighted (DW) MR neurography (MRN) at two different field strengths. MATERIALS AND METHODS: 16 healthy volunteers were investigated at 3.0 T and 1.5 T applying optimized variants of a DW spin-echo echo-planar imaging sequence with short TI inversion recovery fat suppression. Full-volume (FV) and curved sub-volume (CSV) maximum intensity projection (MIP) images were reconstructed and nerve conspicuity was visually assessed. Moreover, visible length and sharpness of the nerves were quantitatively analyzed. RESULTS: On FV MIP images, nerve conspicuity at 3.0 T compared to 1.5 T was worse for brachial plexus (P=0.00228), but better for lumbosacral plexus (P=0.00666). On CSV MIP images, nerve conspicuity did not differ significantly for brachial plexus, but was better at 3.0 T for lumbosacral plexus (P=0.00091). The visible length of the analyzed nerves did not differ significantly with the exception of some lumbosacral nerves, which were significantly longer at 3.0 T. The sharpness of all investigated nerves was significantly higher at 3.0 T by about 40-60% for cervical and 97-169% for lumbosacral nerves. CONCLUSION: DW MRN imaging at 3.0 T compared to 1.5 T is superior for lumbosacral plexus, but not for brachial plexus.

Diffusion-weighted magnetic resonance imaging of breast lesions: the influence of different fat-suppression techniques on quantitative measurements and their reproducibility.

OBJECTIVE: The aim of this study was to evaluate the influence of different fat-suppression techniques on quantitative measurements and their reproducibility when applied to diffusion-weighted imaging (DWI) of breast lesions. METHODS: Twenty-five patients with different types of breast lesions were examined on a clinical 1.5-T magnetic resonance imaging (MRI) system. Two diffusion-weighted sequences with different fat-suppression methods were applied: one with spectral presaturation by inversion recovery (SPIR), and one with short-TI inversion recovery (STIR). The acquisition of both sequence variants was repeated with modified shim volume. Lesion-to-background contrast (LBC), apparent diffusion coefficients (ADC) ADC(0,1000) and ADC(50,1000), and their coefficients of variation (CV) were determined. RESULTS: In four patients, the image quality of DWI with SPIR was insufficient. In the other 21 patients, 46 regions of interest (ROI), including 11 malignant and 35 benign lesions, were analysed. The LBC, ADC(0,1000) and ADC(50,1000) values, which did not differ between initial and repeated measurements, were significantly higher for STIR than for SPIR. The mean CV improved from 10.8 % to 4.0 % (P = 0.0047) for LBC, from 6.3 % to 2.9 % (P = 0.0041) for ADC(0,1000), and from 6.3 % to 2.6 % (P = 0.0049) for ADC(50,1000). CONCLUSION: For STIR compared to SPIR fat suppression, improved lesion conspicuity, higher ADC values, and better measurement reproducibility were found in breast DWI. KEY POINTS: • Quality of fat suppression influences quantitative DWI breast lesion measurements. • In breast DWI, STIR fat suppression worked more reliably than SPIR. • Lesion-to-background contrast and its reproducibility were significantly higher with STIR fat suppression. • Lesional ADCs and their reproducibility were significantly higher with STIR fat suppression.

High temporal and high spatial resolution MR angiography (4D-MRA).

In the first decade of the twenty-first century, whole-body magnetic resonance scanners with high field strengths (and thus potentially better signal-to-noise ratios) were developed. At the same time, parallel imaging and "echo-sharing" techniques were refined to allow for increasingly high spatial and temporal resolution in dynamic magnetic resonance angiography ("time-resolved" = TR-MRA). This technological progress facilitated tracking the passage of intra-venously administered contrast agent boluses as well as the acquisition of volume data sets at high image refresh rates ("4D-MRA"). This opened doors for many new applications in non-invasive vascular imaging, including simultaneous anatomic and functional analysis of many vascular pathologies including arterio-venous malformations. Different methods were established to acquire 4D-MRA using various strategies to acquire k-space trajectories over time in order to optimize imaging according to clinical needs. These include "keyhole"-based techniques (e. g. 4D-TRAK), TRICKS - both with and without projection - and HYPR-reconstruction, TREAT, and TWIST. Some of these techniques were first introduced in the 1980 s and 1990 s, were later enhanced and modified, and finally implemented in the products of major vendors. In the last decade, a large number of studies on the clinical applications of TR-MRA was published. This manuscript provides an overview of the development of TR-MRA methods and the 4D-MRA techniques as they are currently used in the diagnosis, treatment and follow-up of vascular diseases in various parts of the body.

Intravoxel incoherent motion model-based liver lesion characterisation from three b-value diffusion-weighted MRI.

OBJECTIVE: To evaluate intravoxel incoherent motion (IVIM) model-based liver lesion characterisation from three b-value diffusion-weighted imaging (DWI). METHODS: The 1.5-T DWI data from a respiratory gated spin-echo echo-planar magnetic resonance imaging sequence (b = 0, 50, 800 s/mm(2)) were retrospectively analysed in 38 patients with different liver lesions. Conventional apparent diffusion coefficient ADC = ADC(0,800) as well as IVIM-based parameters D' = ADC(50,800), ADC_low = ADC(0,50), and f' were calculated voxel-wise. Sixty-one regions of interest in hepatocellular carcinomas (HCCs, n = 24), haemangiomas (HEMs, n = 11), focal nodular hyperplasias (FNHs, n = 11), and healthy liver tissue (REFs, n = 15) were analysed. Group differences were investigated using Student's t-test and receiver-operating characteristic (ROC) analysis. RESULTS: Mean values ± standard deviations of ADC, D', ADC_low (in 10(-5) mm(2)/s), and f' (in %) for REFs/FNHs/HEMs/HCCs were 130 ± 11/143 ± 27/168 ± 16/113 ± 25, 104 ± 12/123 ± 25/162 ± 18/102 ± 23, 518 ± 66/437 ± 97/268 ± 69/283 ± 120, and 18 ± 3/14 ± 4/6 ± 3/9 ± 5, respectively. Differences between lesions and REFs were more significant for IVIM-based parameters than for conventional ADC. ROC analysis showed the best discriminability between HCCs and FNHs for ADC_low and f' and between HEMs and FNHs or HCCs for D'. CONCLUSION: Three instead of two b-value DWI enables a numerically stable and voxel-wise IVIM-based analysis for improved liver lesion characterisation with tolerable acquisition time. KEY POINTS: • Quantitative analysis of diffusion-weighted MRI helps liver lesion characterisation. • Analysis of intravoxel incoherent motion is superior to apparent diffusion coefficient determination. • Only three b-values enable separation of diffusion and microcirculation effects. • The method presented is numerically stable, with voxel-wise results and short acquisition times.

Feasibility of high-dose dobutamine stress SSFP Cine MRI at 3 Tesla with patient adaptive local RF Shimming using dual-source RF transmission: initial results.

PURPOSE: To investigate the feasibility of high-dose dobutamine stress (HDDS) imaging using SSFP sequences at 3 T employing patient-adaptive local RF-shimming using a dual-source RF transmission system. MATERIALS AND METHODS: 13 Patients underwent a HDDS protocol on a 3 T MRI scanner (Achieva 3.0T-TX, Philips Healthcare), equipped with a dual-source RF transmission system. SSFP cine sequences using patient-adaptive local RF-shimming (RF-S) were compared to cine images acquired without additional shimming. Image quality was evaluated on a 4-point grading scale and number of non-diagnostic segments assessed. Contrast (CN) between myocardium (SIM) and blood pool (SIB) was calculated [(SIB-SIM)/(SIB+SIM)]. RESULTS: Image quality both at rest and maximum stress was significantly improved with RF-S (ED:3.56±0.5 vs. 3.23±0.63; ES:3.4±0.5 vs. 3.1±0.7) compared to no RF-S (ED:2.9±0.72 vs. 2.15±0.78; ES:2.64±0.74 vs. 1.95±0.76; p<0.01). The amount of non-diagnostic segments was significantly reduced when using RF-S at rest and stress (3 vs. 39; 19 vs. 78, p<0.05). All HDDS studies were diagnostic if performed with RF-S (n=13/13) in comparison to conventional shimming (n=5/13). Image contrast was improved for SSFP sequences with RF-S (0.53±0.08) compared to conventional images (0.46±0.09, p=0.06). CONCLUSION: Patient-adaptive local RF-shimming using a dual-source RF transmission system allows for reliable SSFP imaging in a clinical high-dose dobutamine stress protocol at 3 T. RF-S significantly improves image quality and reduces the number of non-diagnostic myocardial segments.

Noninvasive evaluation of cerebral arteriovenous malformations by 4D-MRA for preoperative planning and postoperative follow-up in 56 patients: comparison with DSA and intraoperative findings.

BACKGROUND AND PURPOSE: 4D-MRA is a promising technique in the diagnosis and follow-up of cAVMs. The purpose of this study was to compare 4D-MRA in the pre- and postoperative evaluation of cAVMs with DSA or intraoperative findings as the standards of reference regarding qualitative and quantitative parameters. MATERIALS AND METHODS: Fifty-six consecutive patients with cAVMs (30 women) underwent both 4D-MRA and DSA. Preoperative 4D-MRA was excluded from analysis in 1 patient (movement artifacts). Twenty-five patients underwent surgery on cAVMs and underwent both imaging modalities pre- and postoperatively. 4D-MRA was performed with either 0.5-mol/L gadolinium-diethylene-triamine pentaacetic acid (group 1: voxel size, 1.1 × 1.1 × 1.4 mm(3); 608 ms/dynamic frame; 19 patients) or 1.0-mol/L gadobutrol (group 2: voxel size, 1.1 × 1.1 × 1.1 mm(3); 572 ms/dynamic frame; additional alternating view sharing; 37 patients). Two readers independently reviewed 4D-MRA and DSA regarding the Spetzler-Martin classification, arterial feeders, and postoperative residual filling. Vessel sharpness, vessel diameter, and VBC of 4D-MRA were quantified. RESULTS: Preoperative Spetzler-Martin classification 4D-MRA and DSA ratings matched in 55/55 patients (Spetzler-Martin grades: I, 12; II, 22; III, 15; IV, 5; V, 1), and 93/100 arterial feeders were correctly identified by preoperative 4D-MRA (7 additional arterial feeders identified by DSA only: group 1, 3/19; group 2, 4/36). Postoperative 4D-MRA and DSA matched in 25/25 patients (residual filling, 1/25). Vessel sharpness and diameters did not differ substantially between the 2 groups. VBC was significantly higher in group 2 (P < .005). CONCLUSIONS: 4D-MRA is a reliable tool that allows predicting Spetzler-Martin classification and postoperative residual filling; it hence allows substituting DSA in the pre- and postoperative evaluation of patients with cerebral AVMs.

Characterization of the failing murine heart in a desmin knock-out model using a clinical 3 T MRI scanner.

The purpose of this study was to establish an MRI protocol on a clinical scanner for assessment of left (LV) and right (RV) ventricular myocardial function of the murine heart, and to apply this protocol for the first in vivo assessment of myocardial function in a mouse model of cardiomyopathy (Desmin-/-). MRI was performed on a clinical 3 T whole body MRI system using a dedicated solenoid receive-only coil. Contiguous short axis slices were acquired covering the entire heart using a spoiled cine gradient echo sequence (TR 9-12 ms, TE 3-4 ms, α 25°, 1.0 × 0.23 × 0.23 mm³). Global LV- and RV-myocardial functional parameters such as end-diastolic ventricular volume, ejection fraction (EF), LV mass and cardiac output (CO) of Desmin-/- mice and age-matched controls were determined. Global myocardial functional data of healthy controls (n = 4) were in very good agreement with previously reported data. The transgenic mice (n = 8) revealed a significantly reduced LV- and RV-EF as well as CO. Body weight-normalized LV- and RV-end-diastolic volumes and LV mass were significantly increased. In addition desmin deficient mice exhibited segmental wall thinning and akinesia, suggesting myocardial necrosis. This study demonstrates that clinical 3 T MRI-systems may reliably be used for non-invasive assessment of LV- and RV-myocardial function in normal and in genetically engineered mice with cardiomyopathies. In addition, this proof of principle study presents first in vivo MRI data of the cardiac phenotype of desmin knock-out mice.

Diffusion-weighted magnetic resonance imaging for the detection of ischemic brain lesions in coronary artery bypass graft surgery: relation to extracorporeal circulation and heparinization.

AIM: Cognitive decline is a well recognized complication after on-pump coronary artery bypass graft (CABG) surgery. We investigated whether the design of extracorporeal circulation (ECC) and the extent of perioperative heparinization have an impact on neurological dysfunction. METHODS: Sixty-three CABG surgery patients were randomly perfused with an uncoated ECC-set (group A) or with two different heparin-coated ECC-sets (groups B and C). In groups A and B, systemic heparin was given in doses of 400 IU/kg body weight, whereas group C received 150 IU/kg body weight. ECC sets in group C included a diagonal pump and low priming as opposed to roller pumps in groups A and B. Furthermore, in group C blood contact to surfaces other than endothelium and heparin coated material was eliminated. Brain lesions were detected by diffusion-weighted magnetic resonance imaging (DWI). Neurological complications were assessed clinically until discharge (manifest motoric, sensitive or cognitive disturbance). Biochemical coagulation and inflammation parameters were measured pre-, peri-, and postoperatively. RESULTS: No major neurological events were observed in either group until discharge. DWIs showed 61 new lesions in 19 of 45 patients who terminated all MRI study procedures. Number and volume of the lesions did not differ between groups (P>0.05). Biochemical and inflammatory parameters showed the expected time courses and variations between groups. CONCLUSION: Ischemic brain lesions are frequently observed in CABG surgery patients but are neither associated with clinically relevant neurological complications nor with ECC set-up and intraoperative heparin dosage. DWI may help in the development of new surgical strategies to reduce postoperative brain damage.

Analysing the response in R2* relaxation rate of intracranial tumours to hyperoxic and hypercapnic respiratory challenges: initial results.

OBJECTIVE: To investigate the response in R2* relaxation rate of human intracranial tumours during hyperoxic and hypercapnic respiratory challenges. METHODS: In seven patients with different intracranial tumours, cerebral R2* changes during carbogen and CO(2)/air inhalation were monitored at 3 T using a dynamic multigradient-echo sequence of high temporal and spatial resolution. The R2* time series of each voxel was tested for significant change. Regions of interest were analysed with respect to response amplitude and velocity. RESULTS: The tumours showed heterogeneous R2* responses with large interindividual variability. In the 'contrast-enhancing' area of five patients and in the 'non-tumoral' tissue most voxels showed a decrease in R2* for carbogen. For the 'contrast-enhancing' area of two patients hardly any responses were found. In areas of 'necrosis' and perifocal 'oedema' typically voxels with R2* increase and no response were found for both gases. For tissue responding to CO(2)/air, the R2* changes were of the same order of magnitude as those for carbogen. The response kinetic was generally attenuated in tumoral tissue. CONCLUSION: The spatially resolved determination of R2* changes reveals the individual heterogeneous response characteristic of intracranial human tumours during hyperoxic and hypercapnic respiratory challenges.

Taste does not determine daily intake of dilute sugar solutions in mice.

When a rodent licks a sweet-tasting solution, taste circuits in the central nervous system that facilitate stimulus identification, motivate intake, and prepare the body for digestion are activated. Here, we asked whether taste also determines daily intake of sugar solutions in C57BL/6 mice. We tested several dilute concentrations of glucose (167, 250, and 333 mM) and fructose (167, 250, and 333 mM). In addition, we tested saccharin (38 mM), alone and in binary mixture with each of the sugar concentrations, to manipulate sweet taste intensity while holding caloric value constant. In experiment 1, we measured taste responsiveness to the sweetener solutions in two ways: chorda tympani nerve responses and short-term lick tests. For both measures, the mice exhibited the following relative magnitude of responsiveness: binary mixtures > saccharin > individual sugars. In experiment 2, we asked whether the taste measures reliably predicted daily intake of the sweetener solutions. No such relationship was observed. The glucose solutions elicited weak taste responses but high daily intakes, whereas the fructose solutions elicited weak taste responses and low daily intakes. On the other hand, the saccharin + glucose solutions elicited strong taste responses and high daily intakes, while the saccharin + fructose solutions elicited strong taste responses but low daily intakes. Overall, we found that 1) daily intake of the sweetener solutions varied independently of the magnitude of the taste responses and 2) the solutions containing glucose stimulated substantially higher daily intakes than did the solutions containing isomolar concentrations of fructose. Given prior work demonstrating greater postoral stimulation of feeding by glucose than fructose, we propose that the magnitude of postoral nutritive stimulation plays a more important role than does taste in determining daily intake of dilute sugar solutions.

MR imaging of the prostate at 3.0T with external phased array coil - preliminary results.

INTRODUCTION: Among all imaging modalities, MRI of the prostate has the highest sensitivity to predict extracapsular tumor spread, seems to have added value for the preoperative treatment planning. It is an adjunct tool in patients with high suspicion of prostate cancer and so far negative TRUS-guided biopsies. Due to the higher intrinsic signal, it is expected that 3.0T enables to image the prostate without endorectal coil. Aim of this study was to evaluate the diagnostic accuracy of phased array coil 3.0T MRI in patients with suspicion of prostate cancer. MATERIAL AND METHODS: A high spatial resolution T2-w 3.0T pulse sequence (0.47 x 0.47 x 3mm voxel size) was performed in 26 patients prior to US-guided biopsy. Qualitative analysis comprised visual signal to noise, tissue contrasts and motion artifacts. MR diagnoses were correlated with histology. Diagnostic indices for the detection of prostate cancer in the peripheral zone were calculated. RESULTS: Histopathologic examination revealed pro?state cancer in 12 and benign prostate disorders in 14 patients. Motion artifacts due to peristalsis were rated moderate. Mean visual signal to noise was high. Contrast between peripheral and central zone of the prostate was excellent. MRI had 4 false negative and 2 false positive diagnoses (sensitivity 66.7 %, specificity 86.7 % diagnostic accuracy 76.9%). CONCLUSION: At 3.0T, diagnostic indices for cancer detection seem to be comparable to data reported about endorectal 1.5T MRI. Thus 3.0 T offers new options for MR imaging of the prostate in selected patients who cannot or are not willing to be examined with the endorectal coil.

Diffusion tensor pyramidal tractography in patients with anterior choroidal artery infarcts.

BACKGROUND AND PURPOSE: Anterior choroidal artery (AchoA) stroke often evolves into undulating hemipareses, which sometimes progress to high-grade hemiparesis or hemiplegia but may also completely regress. Spatial relationships of AchoA infarcts to corticospinal tracts (CSTs) and CST integrity were investigated with diffusion tensor imaging (DTI) to identify prognostic parameters related to diffusion anisotropy changes in AchoA stroke. MATERIALS AND METHODS: Twenty-five AchoA stroke patients were prospectively examined with 3T DTI and diffusion tensor tractography (DTT) within a 3-day mean interval after onset. Analysis included the following: 1) stroke size on diffusion-weighted imaging; 2) fractional anisotropy (FA) and apparent diffusion coefficients at the largest stroke extents versus contralateral homologous structures; 3) lesion location related to CST ("involvement"); 4) amount of fiber trajectories of affected versus nonaffected CST ("fiber ratio"); and 5) presence of ipsilateral fiber disruption. Imaging findings were related to clinical status 3 months after symptom onset with respect to favorable, moderate, or unfavorable motor outcome. RESULTS: FA differences (due to FA reduction in the affected versus nonaffected hemisphere) were significantly higher for patients with unfavorable outcome (P=.03). Patients with favorable outcome had nearly symmetrical FA. CSTs were involved in ischemic lesions in all but 2 patients (complete involvement, n=3; partial, n=20). Two CSTs were completely disrupted, and both patients were hemiplegic (no disruption, n=14; partial disruption, n=9). Fiber disruption and CST involvement correlated negatively with motor score after AchoA stroke (P < .01), whereas infarct size did not. CONCLUSION: DTT may explain resulting motor dysfunction in patients with AchoA infarcts with more notably decreased FA being an indicator for unfavorable outcome.

Clinical evaluation of a speed optimized T2 weighted fast spin echo sequence at 3.0 T using variable flip angle refocusing, half-Fourier acquisition and parallel imaging.

This paper aims to demonstrate the capabilities of a speed optimized T(2) weighted single-shot turbo spin echo sequence, using parallel imaging, variable flip angle refocusing and half-Fourier acquisition (FAS-TSE), in comparison with a standard TSE (sTSE) sequence in patients with suspected multiple sclerosis (MS). 33 patients presenting with a clinically isolated syndrome (CIS) suggestive of MS were prospectively examined on a 3.0 T MR system using FAS-TSE and a sTSE sequence. The FAS-TSE (scan time 11 s) and the sTSE (scan time 122 s) were compared regarding lesion detectability, lesion contrast, grey/white matter contrast, overall image quality and artefacts. Scanning parameters affecting image contrast and spatial resolution were kept identical. 208 lesions were detected using the sTSE sequence compared with 183 lesions (88%) using the FAS-TSE. The FAS-TSE was rated inferior regarding lesion contrast. The mean value/range/standard deviation of the lesion/white matter contrast were 0.26/0.06-0.49/0.089, respectively, with the sTSE vs 0.21/0.04-0.40/0.081 with the FAS-TSE. The FAS-TSE was rated inferior regarding overall image quality, but superior regarding motion artefacts. The grey/white matter contrast was qualitatively judged as comparable for both sequences. FAS-TSE provides sufficient T2-SE contrast and diagnostic image quality for whole brain studies in 11 s. It is suited to reduce motion artefacts in restless patients and for fast acquisition of additional scanning planes.

Double inversion recovery brain imaging at 3T: diagnostic value in the detection of multiple sclerosis lesions.

BACKGROUND AND PURPOSE: To prospectively determine the sensitivity in the detection of multiple sclerosis (MS) lesions by using double inversion recovery (DIR), fluid-attenuated inversion recovery (FLAIR), and T2-weighted turbo spin-echo (T2 TSE) MR imaging at 3T. METHODS: Seventeen patients presenting with a clinically isolated syndrome (CIS) suggestive of MS, 9 patients with definite MS, and 6 healthy control subjects were included. Imaging was performed on a 3T MR system using DIR, FLAIR, and T2 TSE sequences. Lesions were counted and classified according to 5 anatomic regions: infratentorial, periventricular, deep white matter, juxtacortical, and mixed white matter-gray matter. The sensitivity at DIR was compared with the corresponding sensitivity at FLAIR and T2 TSE sequence. The contrast between lesions and normal-appearing gray matter, normal-appearing white matter, and CSF was determined for all sequences. RESULTS: Because of higher lesion-white matter contrast, the DIR showed a higher number of lesions compared with the FLAIR (7% gain, P = 0.04) and the T2 TSE (15% gain, P = 0.01). The higher sensitivity was also significant for the infratentorial region compared with the FLAIR (56% gain, P = 0.02) and the T2 TSE (44% gain, P = 0.02). Compared with the FLAIR, no significant changes of the lesion load measurements were observed in the supratentorial brain: slightly higher numbers of periventricular and mixed gray matter-white matter lesions on the DIR were counterbalanced by a slightly reduced sensitivity regarding juxtacortical lesions. CONCLUSION: DIR brain imaging at 3T provides the highest sensitivity in the detection of MS lesions especially in the infratentorial region.

Is the body-coil at 3 Tesla feasible for the MRI evaluation of the painful knee? A comparative study.

The purpose of this study was to compare the in-built body coil of the 3.0-Tesla (T) scanner with a dedicated surface coil of a 1.5 T system regarding knee imaging. We performed an intraindividual prospective clinical trial on 17 patients with knee pain using magnetic resonance imaging (MRI) at 1.5 and 3.0 T systems equipped with identical gradient systems. Proton-density-weighted turbo spin echo sequences with the same spatial resolution and comparable contrast parameters were used. A quantitative measurement of signal to noise ratio (SNR), relative contrast (RC) and contrast to noise ratio (CNR) between muscle and bone marrow was performed, followed by a qualitative assessment of anatomic/pathologic structures and the extent of artefacts. At 3.0 T, 30 lesions (91%) compared to 33 lesions at 1.5 T were detected. The SNR/CNR/RC were moderately reduced at 3.0 T versus 1.5 T (muscle 42 vs 47 and bone 83 vs 112/46 vs 69/0.33 vs 0.43). Motion artefacts from the pulsating popliteal artery were significantly increased at 3.0 T. A visible and measurable signal loss occurred at 3.0 T using the built-in body coil compared with the dedicated 1.5 T knee coil, but nearly all clinically important information could be obtained.

Initial experience with lung-MRI at 3.0T: Comparison with CT and clinical data in the evaluation of interstitial lung disease activity.

OBJECTIVES: We evaluated the feasibility of highfield lung-MRI at 3.0T. A comparison with Computed Tomography (CT) and clinical data regarding the assessment of inflammatory activity in patients with diffuse lung disease was performed. MATERIAL AND METHODS: Prospective evaluation of 21 patients (15 males, 6 females, 43-80 y) with diffuse lung diseases who underwent clinical work-up inclusive laboratory tests, lung-function tests and transbronchial biopsy. After routine helical CT (additional 12 HRCT) a lung-MRI (3.0 Intera, Philips Medical Systems, Best, The Netherlands) using a T2-weighted, cardiac and respiratory triggered Fast-Spinecho-Sequence (TE/TR=80/1500-2500 ms, 22 transverse slices, 7/2mm slice-thickness/-gap) was performed. A pneumologist classified the cases into two groups: A=temporary acute interstitial disease or chronic interstitial lung disease with acute episode or superimposed infection/B=burned out interstitial lung disease without activity. Two blinded CT-radiologists graded the cases in active/inactive disease on the basis of nine morphological criteria each. A third radiologist rated the MRI-cases as active/inactive, depending on the signal-intensities of lung tissues. RESULTS: The pneumologist classified 14 patients into group A and 7 patients into group B. Using CT, 6 cases were classified as active, 15 cases as inactive disease. With MRI 12 cases were classified as active and 9 cases as inactive. In the complete group of 21 patients MRI decisions and CT decisions respectively were false positive/false negative/correct in 2/4/15 respectively 0/8/13 cases. Correct diagnoses were obtained in 72% (MRI) respectively 62% (CT). In the subgroup of 12 cases including HRCT, MRI respectively CT were false positive/false negative/correct in 2/1/9 respectively 0/5/7 cases. Correct diagnoses were obtained in 75% (MRI) respectively 58% (CT). CONCLUSION: Highfield MRI of the lung is feasible and performed slightly better compared to CT in the determination of activity in patients with interstitial lung diseases.

Does high-field MR imaging have an influence on the classification of patients with clinically isolated syndromes according to current diagnostic mr imaging criteria for multiple sclerosis?

BACKGROUND AND PURPOSE: Current MR imaging criteria for multiple sclerosis (MS) do not specify the magnetic field strength. The aim of this study was to investigate whether different MR imaging field strengths, specifically high-field MR imaging, have an impact on the classification of patients with clinically isolated syndromes suggestive of MS, according to MR imaging and diagnostic criteria. METHODS: In a prospective intraindividual comparative study, we examined 40 patients with clinically isolated syndromes (CIS) consecutively with a 1.5 T and 3T MR imaging system, including axial sections of T2 turbo spin-echo, fluid-attenuated inversion recovery, and T1 spin-echo, before and after injection of gadolinium-diethylene-triaminepentaacetic acid. Constant resolution parameters were used for both field strengths. High-signal-intensity white matter lesions with a size of >3 mm were counted and categorized according to their anatomic location in infratentorial, callosal, juxtacortical, periventricular, and other white matter areas. Assessment of the fulfilled Barkhof MR imaging and McDonald diagnostic criteria was made separately for both field strengths in every patient. RESULTS: Eleven patients fulfilled more MR imaging criteria at 3T. Two of these patients fulfilled the criterion of dissemination in space (DIS) according to the first definition of McDonald criteria, which is based on imaging criteria alone. Another patient had DIS only at 3T, according to the second definition of the McDonald criteria including CSF parameters. CONCLUSION: MR field strength, specifically high-field MR imaging, has a substantial influence on the classification of patients with CIS according to imaging and a mild influence on the classification according diagnostic criteria for MS, leading to consequences for prognostic classification, imaging guidelines, and clinical trials.

[MR techniques for noninvasive diagnosis of prostate cancer]. / MR-Techniken zur nicht-invasiven Diagnostik des Prostatakarzinoms.

The diagnosis of prostate cancer is suggested on the basis of an elevated PSA level, abnormal digital exam, and abnormal transrectal ultrasound. US-guided biopsy is used to confirm the diagnosis, but up to 30% of prostate cancer may be missed with this approach. Meanwhile MR imaging and proton MR spectroscopy have emerged as the most sensitive additional tools for the noninvasive evaluation of prostate cancer. This article reviews the clinical indications for MRI of the prostate and summarizes new techniques such as high field strength (3 tesla) and dynamic contrast-enhanced MRI.