Additional Scan Time Research Articles

MR Imaging of Individual Perfusion Reorganization Using Superselective Pseudocontinuous Arterial Spin-Labeling in Patients with Complex Extracranial Steno-Occlusive Disease.

Patients with multiple stenoses or occlusions of the extracranial arteries require an individualized diagnostic approach. We evaluated the feasibility and clinical utility of a novel MR imaging technique for regional perfusion imaging in this patient group. Superselective pseudocontinuous arterial spin-labeling with a circular labeling spot enabling selective vessel labeling was added to routine imaging in a prospective pilot study in 50 patients (10 women, 70.05 ± 10.55 years of age) with extracranial steno-occlusive disease. Thirty-three had infarct lesions. DSC-MR imaging was performed in 16/50 (32%), and cerebral DSA, in 12/50 patients (24%). Vascular anatomy and the distribution of vessel stenoses and occlusions were defined on sonography and TOF-MRA. Stenoses were classified according to the NASCET criteria. Infarct lesions and perfusion deficits were defined on FLAIR and DSC-MR imaging, respectively. Individual perfusion patterns were defined on the superselective pseudocontinuous arterial spin-labeling maps and were correlated with vascular anatomy and infarct lesion localization. The superselective pseudocontinuous arterial spin-labeling imaging sequence could be readily applied by trained technicians, and the additional scan time of 12.7 minutes was well-tolerated by patients. The detected vessel occlusions/stenoses and perfusion patterns corresponded between cerebral DSA and superselective pseudocontinuous arterial spin-labeling maps in all cases. Perfusion deficits on DSC-CBF maps significantly correlated with those on superselective pseudocontinuous arterial spin-labeling maps (Pearson r = 0.9593, P < .01). Individual collateral recruitment patterns were not predictable from the vascular anatomy in 71% of our patients. Superselective pseudocontinuous arterial spin-labeling is a robust technique for regional brain perfusion imaging, suitable for the noninvasive diagnostics of individual perfusion patterns in patients with complex cerebrovascular disease.

Depiction of dentatorubrothalamic tract fibers in patients with Parkinson's disease and multiple sclerosis in deep brain stimulation.

BackgroundWe wanted to depict fibers of the dentatorubrothalamic tract in patients with Parkinson’s disease and multiple sclerosis in order to use this knowledge for clinical routine and to show its relation to the corticospinal tract for deep brain stimulation. Fibers of these white matter tracts were depicted between February 2014 and February 2015 in nine patients of all ages. There were seven men and two women. The mean age was 60 years. We used a 3DT1 sequence for the navigation. Additional scanning time was less than 9 min. Both tracts were portrayed in all patients.ResultsWe were able to successfully portray these white matter tracts in all patients. We visualized the medial and lateral parts of the corticospinal tract by using a region of interest which covered the whole motor cortex. Furthermore we segmented the motor cortex. The fibers ran from this area of the brain through the internal capsule and they could be followed until their entry in the brainstem. The dentatorubrothalamic tract was smaller than the corticospinal tract. It was situated medio-posteriorly of the corticospinal tract. After decussation to the contralateral red nucleus it was localised next to the midline when it entered the motor cortex. From the thalamus on, it proceeds medially and posteriorly of the corticospinal tract further to the motor cortex. Depiction of the whole tract is essential for the differentiation of the dentatorubrothalamic tract with the corticospinal tract.ConclusionsThe depiction of the dentatorubrothalamic tract might be useful for neurosurgeons when deep brain stimulation is planned. Knowing its relation to other white matter tracts can help physicians like neurosurgeons or neurologists avoid side effects and deal with patients with DBS. The position of the electrode might be crucial for a satisfactory outcome.

SU‐G‐IeP1‐15: Towards Accurate Cerebral Blood Flow Quantification with Distortion‐ Corrected Pseudo‐Continuous Arterial Spin Labeling

Purpose:Traditional arterial spin labeling (ASL) acquisitions with echo planar imaging (EPI) readouts suffer from image distortion due to susceptibility effects, compromising ASL's ability to accurately quantify cerebral blood flow (CBF) and assess disease‐specific patterns associated with CBF abnormalities. Phase labeling for additional coordinate encoding (PLACE) can remove image distortion; our goal is to apply PLACE to improve the quantitative accuracy of ASL CBF in humans.Methods:Four subjects were imaged on a 3T Philips Ingenia scanner using a 16‐channel receive coil with a 21/21/10cm (frequency/phase/slice direction) field‐of‐view. An ASL sequence with a pseudo‐continuous ASL (pCASL) labeling scheme was employed to acquire thirty dynamics of single‐shot EPI data, with control and label datasets for all dynamics, and PLACE gradients applied on odd dynamics. Parameters included a post‐labeling delay = 2s, label duration = 1.8s, flip angle = 90°, TR/TE = 5000/23.5ms, and 2.9/2.9/5.0mm (frequency/phase/slice direction) voxel size. “M0” EPI‐reference images and T1‐weighted spin‐echo images with 0.8/1.0/3.3mm (frequency/phase/slice directions) voxel size were also acquired. Complex conjugate image products of pCASL odd and even dynamics were formed, a linear phase ramp applied, and data expanded and smoothed. Data phase was extracted to map control, label, and M0 magnitude image pixels to their undistorted locations, and images were rebinned to original size. All images were corrected for motion artifacts in FSL 5.0. pCASL images were registered to M0 images, and control and label images were subtracted to compute quantitative CBF maps.Results:pCASL image and CBF map distortions were removed by PLACE in all subjects. Corrected images conformed well to the anatomical T1‐weighted reference image, and deviations in corrected CBF maps were evident.Conclusion:Eliminating pCASL distortion with PLACE can improve CBF quantification accuracy using minimal pulse sequence modifications and no additional scan time, improving ASL's clinical applicability.

Scan time minimization in hepatic diffusion-weighted imaging: evaluation of the simultaneous multislice acceleration technique with different acceleration factors and gradient preparation schemes.

To evaluate simultaneous multislice (sms) accelerated diffusion-weighted imaging (DWI) of the liver in comparison to conventional sequences. Ten volunteers underwent DWI of the liver at 1.5 T. Four different sms-accelerated sequences with monopolar and bipolar gradient preparation (MP, BP) and acceleration factors 2 and 3 (sms2-DWI, sms3-DWI) were compared to conventional DWI (c-DWI). Image quality criteria rated on a 5-point Likert scale (5=excellent), image quality sum scores (maximum 120), and ADC were compared using Friedman test and Dunn-Bonferroni post hoc test. Bland-Altman plots were calculated for ADC comparison. p values<0.05 were considered significant. Sms2-DWI offered scan time minimization of 67% without significant difference in image quality (sum score: sms2-DWI MP/BP: 97±8/92±9; c-DWI MP/BP: 99±8/97±8). Sms3-DWI offered slight additional scan time minimization with significantly inferior image quality (sum score: sms3-DWI MP/BP: 75±14/69±14; p<0.001). MP preparation provided slightly higher image quality in sms-DWI without statistical significance. ADC in sms-DWI were significantly lower (sms2-DWI MP 1.01×10(-3) mm(2)/s; c-DWI MP 1.20×10(-3) mm(2)/s; p<0.001). Sms2-DWI provides considerable scan time minimization without significant shortcomings in image quality. Sms3-DWI provides significantly inferior image quality without further scan time minimization. Potentially lower ADC in sms-DWI should be considered in clinical routine.

Motion correction and frequency stabilization for MRS of the human spinal cord.

Subject motion is challenging for MRS, because it can falsify results. For spinal cord MRS in particular, subject movement is critical, since even a small movement > 1 mm) can lead to a voxel shift out of the desired measurement region. Therefore, the identification of motion corrupted MRS scans is essential. In this investigation, MR navigators acquired simultaneously with the MRS data are used to identify a displacement of the spinal cord due to subject motion. It is shown that navigators are able to recognize substantial subject motion (>1 mm) without impairing the MRS measurement. In addition, navigators are easy to apply to the measurement, because no additional hardware and just a minor additional user effort are needed. Moreover, no additional scan time is required, because navigators can be applied in the deadtime of the MRS sequence. Furthermore, in this work, retrospective motion correction combined with frequency stabilization is presented by combining navigators with non-water-suppressed (1)H-MRS, resulting in an improved spectral quality of the spinal cord measurements.

Dixon Sequence with Superimposed Model-Based Bone Compartment Provides Highly Accurate PET/MR Attenuation Correction of the Brain.

Simultaneous PET/MR of the brain is a promising technology for characterizing patients with suspected cognitive impairment or epilepsy. Unlike CT, however, MR signal intensities do not correlate directly with PET photon attenuation correction (AC), and inaccurate radiotracer SUV estimation can limit future PET/MR clinical applications. We tested a novel AC method that supplements standard Dixon-based tissue segmentation with a superimposed model-based bone compartment. We directly compared SUV estimation between MR-based AC and reference CT AC in 16 patients undergoing same-day PET/CT and PET/MR with a single (18)F-FDG dose for suspected neurodegeneration. Three Dixon-based MR AC methods were compared with CT: standard Dixon 4-compartment segmentation alone, Dixon with a superimposed model-based bone compartment, and Dixon with a superimposed bone compartment and linear AC optimized specifically for brain tissue. The brain was segmented using a 3-dimensional T1-weighted volumetric MR sequence, and SUV estimations were compared with CT AC for whole-image, whole-brain, and 91 FreeSurfer-based regions of interest. Modifying the linear AC value specifically for brain and superimposing a model-based bone compartment reduced the whole-brain SUV estimation bias of Dixon-based PET/MR AC by 95% compared with reference CT AC (P < 0.05), resulting in a residual -0.3% whole-brain SUVmean bias. Further, brain regional analysis demonstrated only 3 frontal lobe regions with an SUV estimation bias of 5% or greater (P < 0.05). These biases appeared to correlate with high individual variability in frontal bone thickness and pneumatization. Bone compartment and linear AC modifications result in a highly accurate MR AC method in subjects with suspected neurodegeneration. This prototype MR AC solution appears equivalent to other recently proposed solutions and does not require additional MR sequences and scanning time. These data also suggest that exclusively model-based MR AC approaches may be adversely affected by common individual variations in skull anatomy.

Performance of simultaneous high temporal resolution quantitative perfusion imaging of bladder tumors and conventional multi-phase urography using a novel free-breathing continuously acquired radial compressed-sensing MRI sequence

PurposeTo investigate the feasibility of high temporal resolution quantitative perfusion imaging of bladder tumors performed simultaneously with conventional multi-phase MR urography (MRU) using a novel free-breathing continuously acquired radial MRI sequence with compressed-sensing reconstruction. Methods22 patients with bladder lesions underwent MRU using GRASP (Golden-angle RAdial Sparse Parallel) acquisition. Multi-phase contrast-enhanced abdominopelvic GRASP was performed during free-breathing (1.4×1.4×3.0mm3 voxel size; 3:44min acquisition). Two dynamic datasets were retrospectively reconstructed by combining different numbers of sequentially acquired spokes into each dynamic frame: 110 spokes per frame for 25-s temporal resolution (serving as conventional MRU for clinical interpretation) and 8 spokes per frame for 1.7-s resolution. Using 1.7-s resolution images, ROIs were placed within bladder lesions and normal bladder wall, a femoral artery arterial input function was generated, and the Generalized Kinetic Model was applied. ResultsBiopsy/cystectomy demonstrated 16 bladder tumors (13 stage≥T2, 3 stage≤T1) and 6 benign lesions. All lesions were well visualized using 25-s clinical multi-phase images. Using 1.7-s resolution images, Ktrans was significantly higher in tumors (0.38±0.24) than normal bladder (0.12±0.02=8, p<0.001) or benign lesions (0.15±0.04, p=0.033). Ratio between Ktrans of lesions and normal bladder was nearly double for tumors than benign lesions (4.3±3.4 vs. 2.2±1.6), and Ktrans was nearly double in stage≥T2 than stage≤T1 tumors (0.44±0.24 vs. 0.24±0.24), although these did not approach significance (p=0.180–0.209), possibly related to small sample size. ConclusionGRASP allows simultaneous quantitative high temporal resolution perfusion of bladder lesions during clinical MRU examinations using only one contrast injection and without additional scan time.

Combining phase images from array coils using a short echo time reference scan (COMPOSER).

PurposeTo develop a simple method for combining phase images from multichannel coils that does not require a reference coil and does not entail phase unwrapping, fitting or iterative procedures.Theory and MethodsAt very short echo time, the phase measured with each coil of an array approximates to the phase offset to which the image from that coil is subject. Subtracting this information from the phase of the scan of interest matches the phases from the coils, allowing them to be combined. The effectiveness of this approach is quantified in the brain, calf and breast with coils of diverse designs.ResultsThe quality of phase matching between coil elements was close to 100% with all coils assessed even in regions of low signal. This method of phase combination was similar in effectiveness to the Roemer method (which needs a reference coil) and was superior to the rival reference‐coil‐free approaches tested.ConclusionThe proposed approach—COMbining Phase data using a Short Echo‐time Reference scan (COMPOSER)—is a simple and effective approach to reconstructing phase images from multichannel coils. It requires little additional scan time, is compatible with parallel imaging and is applicable to all coils, independent of configuration. Magn Reson Med 77:318–327, 2017. © 2015 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine

Statistical estimation of T1 relaxation times using conventional magnetic resonance imaging

Quantitative T1 maps estimate T1 relaxation times and can be used to assess diffuse tissue abnormalities within normal-appearing tissue. T1 maps are popular for studying the progression and treatment of multiple sclerosis (MS). However, their inclusion in standard imaging protocols remains limited due to the additional scanning time and expert calibration required and susceptibility to bias and noise. Here, we propose a new method of estimating T1 maps using four conventional MR images, which are intensity-normalized using cerebellar gray matter as a reference tissue and related to T1 using a smooth regression model. Using cross-validation, we generate statistical T1 maps for 61 subjects with MS. The statistical maps are less noisy than the acquired maps and show similar reproducibility. Tests of group differences in normal-appearing white matter across MS subtypes give similar results using both methods.

Intensity correction for multichannel hyperpolarized 13C imaging of the heart.

Develop and test an analytic correction method to correct the signal intensity variation caused by the inhomogeneous reception profile of an eight-channel phased array for hyperpolarized (13) C imaging. Fiducial markers visible in anatomical images were attached to the individual coils to provide three dimensional localization of the receive hardware with respect to the image frame of reference. The coil locations and dimensions were used to numerically model the reception profile using the Biot-Savart Law. The accuracy of the coil sensitivity estimation was validated with images derived from a homogenous (13) C phantom. Numerical coil sensitivity estimates were used to perform intensity correction of in vivo hyperpolarized (13) C cardiac images in pigs. In comparison to the conventional sum-of-squares reconstruction, improved signal uniformity was observed in the corrected images. The analytical intensity correction scheme was shown to improve the uniformity of multichannel image reconstruction in hyperpolarized [1-(13) C]pyruvate and (13) C-bicarbonate cardiac MRI. The method is independent of the pulse sequence used for (13) C data acquisition, simple to implement and does not require additional scan time, making it an attractive technique for multichannel hyperpolarized (13) C MRI.

Localizing Pain Matrix and Theory of Mind networks with both verbal and non-verbal stimuli

Functional localizer tasks allow researchers to identify brain regions in each individual's brain, using a combination of anatomical and functional constraints. In this study, we compare three social cognitive localizer tasks, designed to efficiently identify regions in the “Pain Matrix,” recruited in response to a person's physical pain, and the “Theory of Mind network,” recruited in response to a person's mental states (i.e. beliefs and emotions). Participants performed three tasks: first, the verbal false-belief stories task; second, a verbal task including stories describing physical pain versus emotional suffering; and third, passively viewing a non-verbal animated movie, which included segments depicting physical pain and beliefs and emotions. All three localizers were efficient in identifying replicable, stable networks in individual subjects. The consistency across tasks makes all three tasks viable localizers. Nevertheless, there were small reliable differences in the location of the regions and the pattern of activity within regions, hinting at more specific representations. The new localizers go beyond those currently available: first, they simultaneously identify two functional networks with no additional scan time, and second, the non-verbal task extends the populations in whom functional localizers can be applied. These localizers will be made publicly available.

Cine viability magnetic resonance imaging of the heart without increased scan time

Cardiac magnetic resonance imaging (MRI) provides information about myocardial morphology, function, and viability from cine, tagged, and late gadolinium enhancement (LGE) images, respectively. While the cine and tagged images are acquired in a time-resolved fashion, the LGE images are acquired at a single timeframe. The purpose of this work is to develop a method for generating cine LGE images without additional scan time. The motion field is extracted from the tagged images, and is then used to guide the deformation of the infarcted region from the acquired LGE image at the acquired timeframe to any other timeframe. Major techniques for motion estimation, including harmonic phase (HARP) and optical flow analysis, are tested in this work for motion estimation. The proposed method is tested on numerical phantom and images from four human subjects. The generated cine LGE images showed both viability and wall motion information in the same set of images without additional scan time or image misregistration problems. The band-pass optical flow analysis resulted in the most accurate motion estimation compared to other methods, especially HARP, which fails to track points at the myocardial boundary. Infarct transmurality from the generated images showed good agreement with myocardial strain, and wall thickening showed good agreement with that measured from conventional cine images. In conclusion, the developed technique allows for generating cine LGE images that enable simultaneous display of wall motion and viability information. The generated images could be useful for estimating myocardial contractility reserve and for treatment prognosis.

Visualization of the medial forebrain bundle using diffusion tensor imaging.

Diffusion tensor imaging is a technique that enables physicians the portrayal of white matter tracts in vivo. We used this technique in order to depict the medial forebrain bundle (MFB) in 15 consecutive patients between 2012 and 2015. Men and women of all ages were included. There were six women and nine men. The mean age was 58.6 years (39–77). Nine patients were candidates for an eventual deep brain stimulation. Eight of them suffered from Parkinson‘s disease and one had multiple sclerosis. The remaining six patients suffered from different lesions which were situated in the frontal lobe. These were 2 metastasis, 2 meningiomas, 1 cerebral bleeding, and 1 glioblastoma. We used a 3DT1-sequence for the navigation. Furthermore T2- and DTI- sequences were performed. The FOV was 200 × 200 mm2, slice thickness 2 mm, and an acquisition matrix of 96 × 96 yielding nearly isotropic voxels of 2 × 2 × 2 mm. 3-Tesla-MRI was carried out strictly axial using 32 gradient directions and one b0-image. We used Echo-Planar-Imaging (EPI) and ASSET parallel imaging with an acceleration factor of 2. b-value was 800 s/mm2. The maximal angle was 50°. Additional scanning time was < 9 min. We were able to visualize the MFB in 12 of our patients bilaterally and in the remaining three patients we depicted the MFB on one side. It was the contralateral side of the lesion. These were 2 meningiomas and one metastasis. Portrayal of the MFB is possible for everyday routine for neurosurgical interventions. As part of the reward circuitry it might be of substantial importance for neurosurgeons during deep brain stimulation in patients with psychiatric disorders. Surgery in this part of the brain should always take the preservation of this white matter tract into account.

Combining task-evoked and spontaneous activity to improve pre-operative brain mapping with fMRI

Noninvasive localization of brain function is used to understand and treat neurological disease, exemplified by pre-operative fMRI mapping prior to neurosurgical intervention. The principal approach for generating these maps relies on brain responses evoked by a task and, despite known limitations, has dominated clinical practice for over 20years. Recently, pre-operative fMRI mapping based on correlations in spontaneous brain activity has been demonstrated, however this approach has its own limitations and has not seen widespread clinical use. Here we show that spontaneous and task-based mapping can be performed together using the same pre-operative fMRI data, provide complimentary information relevant for functional localization, and can be combined to improve identification of eloquent motor cortex. Accuracy, sensitivity, and specificity of our approach are quantified through comparison with electrical cortical stimulation mapping in eight patients with intractable epilepsy. Broad applicability and reproducibility of our approach are demonstrated through prospective replication in an independent dataset of six patients from a different center. In both cohorts and every individual patient, we see a significant improvement in signal to noise and mapping accuracy independent of threshold, quantified using receiver operating characteristic curves. Collectively, our results suggest that modifying the processing of fMRI data to incorporate both task-based and spontaneous activity significantly improves functional localization in pre-operative patients. Because this method requires no additional scan time or modification to conventional pre-operative data acquisition protocols it could have widespread utility.

Non-Cartesian balanced steady-state free precession pulse sequences for real-time cardiac MRI.

To develop a new spiral-in/out balanced steady-state free precession (bSSFP) pulse sequence for real-time cardiac MRI and compare it with radial and spiral-out techniques. Non-Cartesian sampling strategies are efficient and robust to motion and thus have important advantages for real-time bSSFP cine imaging. This study describes a new symmetric spiral-in/out sequence with intrinsic gradient moment compensation and SSFP refocusing at TE = TR/2. In vivo real-time cardiac imaging studies were performed to compare radial, spiral-out, and spiral-in/out bSSFP pulse sequences. Furthermore, phase-based fat/water separation taking advantage of the refocusing mechanism of the spiral-in/out bSSFP sequence was also studied. The image quality of the spiral-out and spiral-in/out bSSFP sequences was improved with off-resonance and k-space trajectory correction. The spiral-in/out bSSFP sequence had the highest signal-to-noise ratio (SNR), contrast-to-noise ratio, and image quality ratings, with spiral-out bSSFP sequence second in each category and the radial bSSFP sequence third. The spiral-in/out bSSFP sequence provides separated fat and water images with no additional scan time. In this study, a new spiral-in/out bSSFP sequence was developed and tested. The superiority of spiral bSSFP sequences over the radial bSSFP sequence in terms of SNR and reduced artifacts was demonstrated in real-time MRI of cardiac function without image acceleration.

Diffusion tensor imaging – Arcuate fasciculus and the importance for the neurosurgeon

ObjectiveTumors in eloquent areas of the brain like Broca or Wernicke might have disastrous consequences for patients. We intended to visualize the arcuate fasciculus (AF) and to demonstrate his relation with the corticospinal tract and the visual pathway using diffusion tensor imaging (DTI). MethodsWe depicted between 2012 and 2014 the AF in 71 patients. Men and women of all ages were included. Eleven patients had postoperative controls also. We used a 3DT1-sequence for the navigation. Furthermore T2- and DTI-sequences were performed. The FOV was 200×200mm2, slice thickness 2mm, and an acquisition matrix of 96×96 yielding nearly isotropic voxels of 2×2×2mm. 3-Tesla-MRI was carried out strictly axial using 32 gradient directions and one b0-image. We used Echo-Planar-Imaging (EPI) and ASSET parallel imaging with an acceleration factor of 2. b-Value was 800s/mm2. Additional scanning time was less than 9min. ResultsAF was portrayed in 63 patients bilaterally. In one glioblastoma patient it was impossible to visualize the left AF and in seven other patients we could not portray the right one. The lesions affected AF by disrupting or displacing the fibers. ConclusionsDTI might be a useful tool to portray AF. It is time-saving and can be used to preserve morbidity in patients with lesions in eloquent brain areas. It might give deeper insights of the white matter and the reorganization of AF-fibers postoperatively.

Use of the temporal median and trimmed mean mitigates effects of respiratory motion in multiple-acquisition abdominal diffusion imaging

Respiratory motion commonly confounds abdominal diffusion-weighted magnetic resonance imaging, where averaging of successive samples at different parts of the respiratory cycle, performed in the scanner, manifests the motion as blurring of tissue boundaries and structural features and can introduce bias into calculated diffusion metrics. Storing multiple averages separately allows processing using metrics other than the mean; in this prospective volunteer study, median and trimmed mean values of signal intensity for each voxel over repeated averages and diffusion-weighting directions are shown to give images with sharper tissue boundaries and structural features for moving tissues, while not compromising non-moving structures. Expert visual scoring of derived diffusion maps is significantly higher for the median than for the mean, with modest improvement from the trimmed mean. Diffusion metrics derived from mono- and bi-exponential diffusion models are comparable for non-moving structures, demonstrating a lack of introduced bias from using the median. The use of the median is a simple and computationally inexpensive alternative to complex and expensive registration algorithms, requiring only additional data storage (and no additional scanning time) while returning visually superior images that will facilitate the appropriate placement of regions-of-interest when analysing abdominal diffusion-weighted magnetic resonance images, for assessment of disease characteristics and treatment response.

Value of Additional Cervicothoracic Sagittal T2-Weighted Images in Elderly Patients with Symptoms Suggestive of Lumbar Spinal Stenosis

Degenerative spinal stenosis in the lumbar or cervical spine is a common disease in the elderly population, because these are the most mobile segments of the spine. Degenerative spinal stenosis can present as concurrent lumbar spinal stenosis (LSS) and cervical spinal stenosis (CSS), which was first described by Teng and Papatheodorou (1) in 1964. Several studies–performed using clinical or radiologic diagnoses based on radiography, myelography, or CT findings only in symptomatic patients–have shown the incidence of tandem spinal stenosis (TSS) to range from 5% to 25% (2-4). The incidence of TSS in the asymptomatic population is expected to be higher than suggested in past reports. MR imaging is now widely used for the evaluation and diagnosis of spinal disorders (5). For the past several years in our institute, additional cervicothoracic sagittal T2-weighted images (CT-sag-T2WI) have been routinely obtained in the lumbar spine MR images for all patients. Using spine coils for scanning the lumbar spine, additional CT-sag-T2WI can easily be obtained without changing the coils and with an additional scan time of less than two minutes. We have frequently observed TSS in the Value of Additional Cervicothoracic Sagittal T2-Weighted Images in Elderly Patients with Symptoms Suggestive of Lumbar Spinal Stenosis 요추 척추관 협착증의 증상을 보이는 노인 환자에서 경흉추 시상 단면 T2 강조 자기공명영상 소견의 가치

Automatic synthesis of cine viability MRI images for evaluation of coronary heart disease.

Coronary heart disease (CHD) is the leading cause of death worldwide. Cardiac magnetic resonance imaging (MRI) is a valuable imaging modality, as it can noninvasively provide information about myocardial function, viability, and morphology. Viability delayed-enhancement (DE) images are acquired at a single timeframe while myocardial functional (tagged) images are acquired as a cine loop of timeframes throughout the cardiac cycle. In this work, we propose a method for estimating DE images at all timeframes in the cardiac cycle without additional scan time to show both viability and functional information in the same image. The method is based on generating a dense motion field of the heart from the acquired tagged images, and then applying the extracted field to the acquired DE image. The developed technique is accurate in generating cine DE images and providing simultaneous information about myocardial viability and wall motion for comprehensive patient evaluation and optimal treatment selection.

Abstract P322: Myocardial Contraction Fraction is an Independent Predictor of Incident Adverse Cardiovascular Events; The Framingham Heart Study

Introduction: Myocardial contraction fraction (MCF) is the ratio of left ventricular (LV) stroke volume to myocardial volume, and thus a measure of LV pumping capacity per unit of myocardium. We sought to determine whether MCF measured using current steady-state free precession (SSFP) cardiac magnetic resonance (CMR) sequences was an independent predictor of incident “hard” cardiovascular disease (CVD) events, defined by myocardial infarction (MI), stroke, unstable angina (UA), hospitalized heart failure (HF) or CVD death in a community dwelling cohort initially free of these CVD events. Methods: 1794 members of the Framingham Heart Study Offspring cohort (aged 65±9 years) underwent CMR between 2002-2006 using a 1.5-Tesla system with contiguous multislice SSFP cine imaging to encompass the left ventricle. MCF was determined from the cine images by a single observer blinded to participant characteristics. We tracked incident hard CVD events over median 6.5-year follow up and used Cox proportional hazards models (adjusted for age, sex, body mass index, systolic blood pressure, diabetes, dyslipidemia, smoking, treatment for hypertension) to determine hazard of hard CVD events per increment (0.10) of MCF. Results: MCF was determined in 1776 (99%) Offspring (835 men). Overall, MCF was greater in women (0.92±0.14 vs. 0.78±0.15 for men), p&lt;0.0001. There were 60 incident hard CVD events during follow up. Incident hard events included 26 MI, 2 UA, 13 stroke, 14 hospitalized HF and 5 CVD deaths. Offspring experiencing an incident event had lower MCF (0.78±0.19 vs. 0.86±0.15 for those free of events), p=0.002. On MV-adjusted Cox proportional hazards analyses, a greater MCF was protective against hard CVD events, HR [95% confidence intervals] = 0.76 [0.63 - 0.93] per 0.10 increment of MCF. Conclusion: Over 6.5-year follow-up, greater MCF is protective against major adverse CVD events, even after adjustment for traditional CVD risk factors in a community dwelling cohort of middle-aged and older predominantly European-descended adults. Determination of MCF requires only knowledge of LV stroke volume and myocardial volume, both of which are routinely determined in a standard CMR examination of the left ventricle, and thus imposes no additional scan-time or analysis burden. While MCF may be clinically useful for prediction of risk for incident hard CVD events, its potential value in younger age groups and other ethnicities remains to be determined.