Biomedical subjects

James W Goldfarb

Publications and source records attributed to James W Goldfarb.

8 recordsLinked to original sources

PubMed2006

Cardiac-synchronized gadolinium-enhanced MR angiography: preliminary experience for the evaluation of the thoracic aorta.

Gadolinium (Gd)-enhanced three-dimensional breath-hold magnetic resonance cardiac-synchronized angiography was performed in 13 patients suspected or known to have thoracic aortic disease. High-quality angiograms of the ascending/descending thoracic aorta and coronary arteries were obtained with this method. MR angiograms were compared with Gd-enhanced angiograms obtained without cardiac synchronization. Synchronized imaging showed significantly better aortic valve leaflet and proximal coronary artery depiction. Synchronization reduced motion artifacts, allowing better visualization of the aortic root and proximal coronary arteries.

Adult↗

PubMed2006

Free-breathing delayed hyperenhanced imaging of the myocardium: a clinical application of real-time navigator echo imaging.

PURPOSE: To compare a free-breathing (FB) acquisition with the current standard of breath-holding (BH) in a clinical setting using identical two-dimensional MR pulse sequences for imaging of myocardial delayed hyperenhancement. MATERIALS AND METHODS: Two-dimensional gadolinium-enhanced images were acquired using FB and BH techniques in 18 subjects to evaluate delayed enhancement of myocardial infarction. The FB acquisition used a navigator echo to monitor the position of the right hemidiaphragm for respiratory gating and correction. Visual analysis using a 16-segment model, quantitative signal difference to noise ratios, and percent left ventricle (LV) viability measurements for the two acquisition types were statistically compared. RESULTS: An excellent agreement between two-dimensional BH and two-dimensional FB acquisitions was found. In one patient, a nontransmural infarct was seen only in the FB images. There were no statistically significant differences in the number of infarcted segments or the measured signal difference to noise ratios (SDNR) between the two methods. Linear regression and Bland Altman analysis of the percentage LV viable myocardium yielded a good fit and narrow limits of agreement. CONCLUSION: An FB navigator echo acquisition can be effectively used in the setting of myocardial delay hyperenhanced imaging. Image quality is similar or superior to that of BH imaging.

Adult↗

PubMed2005

Quantitative breath-hold monitoring of myocardial gadolinium enhancement using inversion recovery TrueFISP.

The purpose of this work was to develop and evaluate the accuracy of a breath-hold IR-TrueFISP acquisition capable of monitoring gadolinium (Gd) concentrations through T1 measurements in the left ventricular blood pool and segments of the myocardium over an extended duration. Measurements using a phantom were performed to assess the accuracy of the technique. Accurate T1 measurements in the expected range after contrast agent administration were obtained with several theoretical formulations. Accurate T1 values before the administration of the contrast agent were obtained only when the incomplete recovery of magnetization during the delay time (TD) between imaging segments was incorporated into the observed signal intensity calculations. T1 measurements over a 1-hr time period were performed in four subjects with known myocardial infarctions. In this small study, Gd differences between recent and old myocardial infarctions were observed.

Aged↗

PubMed2005

On the cause of spatial displacement of long T1 species in segmented inversion recovery prepared imaging.

Using inversion recovery steady-state free precession segmented k-space imaging for the detection of myocardial infarction, we noticed that some structures appeared in the wrong locations of the image. In this work, the spatial displacement is demonstrated and explained from both theoretical and experimental points of view. The effect is due to a change in phase from segment to segment of the detected magnetization from species with long T1's such as cysts, fluid collections, and cerebrospinal fluid. Depending on the number of k-space segments and view ordering, structures can be replicated throughout the image or displaced by half of the phase-encoding field of view.

Humans↗

PubMed2004

The SENSE ghost: field-of-view restrictions for SENSE imaging.

PURPOSE: To describe a known (but undocumented) limitation in parallel imaging using simulation and experiment. This limitation consists of an artifact that appears when the imaging field of view (FOV) is less than the object size. This study demonstrates this artifact in the phase- and partition-encoding dimensions. MATERIALS AND METHODS: One-dimensional simulations as well as in vivo experiments were performed with FOVs greater and less than the object being imaged. Full-FOV, reduced-FOV, and SENSE reconstructions were visually compared. RESULTS: Image artifacts occurred when the final SENSE FOV was smaller than the object being imaged. This artifact, termed the SENSE ghost, was a residual fold-over/aliasing artifact. Its location was in the central portion of the image rather than at the edges of the image. CONCLUSION: This image artifact results from an FOV being smaller than the imaged object. The SENSE reconstruction cannot unfold this additional fold-over, and will place it in a predictable image location based on the SENSE reduction factor. Knowledge of this artifact is necessary when prescribing SENSE acquisitions and interpreting the resulting images.

Artifacts↗

PubMed2004

Parallel magnetic resonance imaging using coils with localized sensitivities.

The purpose of this study was to present clinical examples and illustrate the inefficiencies of a conventional reconstruction using a commercially available phased array coil with localized sensitivities. Five patients were imaged at 1.5 T using a cardiac-synchronized gadolinium-enhanced acquisition and a commercially available four-element phased array coil. Four unique sets of images were reconstructed from the acquired k-space data: (a) sum-of-squares image using four elements of the coil; localized sum-of-squares images from the (b) anterior coils and (c) posterior coils and a (c) local reconstruction. Images were analyzed for artifacts and usable field-of-view. Conventional image reconstruction produced images with fold-over artifacts in all cases spanning a portion of the image (mean 90 mm; range 36-126 mm). The local reconstruction removed fold-over artifacts and resulted in an effective increase in the field-of-view (mean 50%; range 20-70%). Commercially available phased array coils do not always have overlapping sensitivities. Fold-over artifacts can be removed using an alternate reconstruction method. When assessing the advantages of parallel imaging techniques, gains achieved using techniques such as SENSE and SMASH should be gauged against the acquisition time of the localized method rather than the conventional sum-of-squares method.

Adult↗

PubMed2003

Simultaneous magnetic resonance gadolinium-enhanced 2D perfusion and 3D angiographic imaging.

A method was implemented and tested that allows the simultaneous acquisition of magnetic resonance 2D slice selective perfusion and 3D angiographic data during a single bolus injection of a contrast agent. High quality contrast-enhanced perfusion images and angiograms of the lung, kidney and heart were obtained in healthy volunteers. Combined perfusion and angiography provided additional information with an acceptable increase in acquisition time. No image artifacts were attributed to the technique. The combined information may be useful in detecting, as well as characterizing, vascular abnormalities.

Adult↗

PubMed2002

The value of single-shot black-blood MR imaging for mapping of the coronary arteries: a comparison of four different orientations during breath-holding and free breathing.

The value of ECG-gated single-shot black-blood MR imaging for rapid visualization of the origin and course of the coronary arteries was investigated. The study population included 28 patients with known or suspected cardiac disease. ECG-gated single-shot black-blood MR acquisitions were acquired in the transverse, coronal, sagittal and LAO orientations, during free breathing and breath-holding. The origin of the left coronary artery was most frequently visualized in the coronal and LAO orientations and the origin of the right coronary artery was most frequently visualized in the LAO orientation. Overall, no significant difference was found for the visualization of the coronary artery segments and the overall image quality among acquisitions during breath-holding and free breathing. ECG-gated single-shot black-blood MR imaging (HASTE) appears to be a time-efficient and robust method for mapping of the entire coronary artery tree, without the need for breath-holding. The LAO orientation provides the most consistent visualization of the origins and major coronary artery segments.

Adult↗