David W. Stanley

Non‐contrast renal artery MRA using an inflow inversion recovery steady state free precession technique (Inhance): Comparison with 3D contrast‐enhanced MRA

To assess the performance of a three‐dimensional (3D) non‐contrast respiratory‐triggered steady state free precession (SSFP) pulse sequence for detection of renal artery stenosis.

Gadolinium Enhanced Magnetic Resonance Urography for Upper Urinary Tract Malignancy

PURPOSE We retrospectively evaluated the accuracy of gadolinium enhanced magnetic resonance urography to detect upper urinary tract tumors. MATERIALS AND METHODS A total of 91 magnetic resonance urography studies for suspected upper tract malignancy were done in 70 males and 18 females with a mean age of 71.7 years. Breath hold coronal T2-weighted single shot fast spin-echo and breath-hold coronal 3-dimensional T1-weighted spoiled gradient-recalled echo images with fat suppression were obtained during the nephrographic and excretory phases after intravenous injection of gadolinium based contrast material. Two radiologists independently reviewed magnetic resonance images for a tumor by 4 regions (right/left and renal collecting system/ureter). Sensitivity, specificity and accuracy were calculated. RESULTS A total of 35 urinary tract regions in 18 males and 7 females with a mean age of 70.4 years were confirmed to have an upper tract malignant tumor and 219 urinary tract regions were confirmed to be tumor-free. Sensitivity, specificity and accuracy to detect upper urinary tract malignancy were 74.3%, 96.8% and 93.7% for reviewer 1, and 62.9%, 96.3% and 91.7% for reviewer 2, respectively. When patients with a ureteral stent or nephrostomy tube were excluded from analysis, sensitivity, specificity and accuracy were 86.2%, 99.5% and 97.7% for reviewer 1, and 72.4%, 97.9% and 94.6% for reviewer 2, respectively. CONCLUSIONS Gadolinium enhanced magnetic resonance urography is accurate to detect upper urinary tract malignant tumors.

The Compartments of the Foot: A 3-Tesla Magnetic Resonance Imaging Study with Clinical Correlates for Needle Pressure Testing:

Background: Reliable measurement of subfascial pressures represents an essential part of compartment syndrome management. To date, there is neither consensus on the number or location of foot compartments, nor a standardized protocol for needle placement. The purpose of this study was to devise a new system using 3-Tesla MRI that assesses the number and location of these compartments. Methods: To document the specific location of foot compartments, high resolution 3-Tesla MRI (General Electric, Milwaukee, WI) was coupled with a dedicated transmit-receive high signal-to-noise foot/ankle coil (IGC-Medical Advances, Milwaukee, WI). Individual compartments were highlighted and mapped to T1-weighted MRI. Three-dimensional image analysis allowed standardized needle placement recommendations. Results: Six feet from healthy volunteers were imaged. From these, ten compartments were described: (1) medial, (2) central superficial, (3) central deep (adductor), (4) lateral, (5–8) interossei, (9) calcaneal, and (10) skin. Optimal needle placement and depth were identified. Conclusions: The proposed system allowed us to assess the number and location of foot compartments. Computer image analysis enabled us to define exact points for needle insertion and depth of penetration for accurate pressure monitoring.

Evaluation of intraneural ganglion cysts using three-dimensional fast spin echo-cube.

To compare conventional two‐dimensional fast spin echo (FSE) MRI sequences with a three‐dimensional FSE extended echo train acquisition method, known as Cube, in the evaluation of intraneural ganglion cysts. Also, to demonstrate that Cube enables the consistent identification and thorough characterization of the cystic joint connection, and therefore improves patient care by superior preoperative planning.

Evaluation of ganglion cysts using vastly undersampled isotropic projection reconstruction (VIPR)

For some atypical para‐articular ganglia, the presence of a joint connection is highly controversial. The proper preoperative diagnosis and identification of this joint connection for ganglion cysts is important for patient treatment and outcome. MRI is the imaging modality of choice when evaluating such lesions, but the detection of subtle joint connections remains difficult with conventional MR protocols. We investigated the utility of a steady‐state free‐precession acquisition with isotropic high resolution using the vastly undersampled isotropic projection reconstruction (VIPR) pulse sequence to determine if joint connections for ganglion cysts could be seen more effectively, using the knee region as a model. We evaluated four patients: two with peroneal intraneural ganglion cysts, one with adventitial cystic disease of the popliteal artery, and one patient with a more typical extraneural (intramuscular) cyst. Both conventional MR and VIPR techniques were used. In our clinical experience, we found VIPR to be superior to conventional MR techniques in detecting and depicting joint connections in typical and atypical ganglion cysts around the knee. J. Magn. Reson. Imaging 2007.

Lightweight, compact, and high-performance 3T MR system for imaging the brain and extremities: FOO et al.

To build and evaluate a small‐footprint, lightweight, high‐performance 3T MRI scanner for advanced brain imaging with image quality that is equal to or better than conventional whole‐body clinical 3T MRI scanners, while achieving substantial reductions in installation costs.

Joint denoising and motion correction: initial application in single-shot cardiac MRI

Background Single-shot (SSH) pulse sequences in CMR are beneficial for rapid image acquisition that is robust to motion, especially in arrhythmic patients or poor breath-holders. However, this fast scanning technique trades scan time for a lower signal-to-noise ratio compared to conventional multi-shot acquisitions. Here we propose a motion-compensated denoising technique that improves the image quality from multiple free-breathing singleshot acquisitions.

Geotechnical Asset Management Plan: Analysis of Life-Cycle Cost and Risk

The Alaska Department of Transportation and Public Facilities is implementing a geotechnical asset management program for its rock and soil slopes, retaining walls, and material sites. The program includes a geographic inventory, periodic site assessment of condition and risk, and a quantitative investment analysis that includes risk and life-cycle cost. In developing the program, the department has addressed all the requirements of federal laws and the proposed regulations for performance measurement and transportation asset management (TAM) plans. Ultimately, the goal is to include these asset classes within the department’s TAM plan. This paper describes the motivation and goals of the analysis; performance assessment process; means of integrating risk with life-cycle cost; models of treatment cost, effectiveness, and deterioration; and methods for assessing the likelihood and consequences of service disruption. Examples focus on the inputs and results for rock slopes.

Robust fat saturation applied to late enhancement

Background Late Gadolinium Enhancement (LGE) allows imaging of infarction and cardiomyopathies by measuring the accumulation of contrast agent within the myocardium. The shortened T1 relaxation time compared to healthy myocardium is imaged by an inversion recovery (IR) prepared segmented fast gradient echo sequence in which pathology and fat show as bright signal. The fat signal can lead to misinterpretation and poor visualization of epicardial enhancement. In previous work fat was suppressed by using two appropriately timed fat-selective RF pulses which re-invert and invert fat signal [Foo et al., JMRI, 2007] but this technique was sensitive to off-resonance and heart rate variations. The goal of the present work is to make two improvements to fat-saturated LGE: (1) increase robustness against B0 and B1 variations by using asymmetric adiabatic RF pulses, and (2) increase robustness against heart rate variations through dynamic timing of fat-selective RF pulses.