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Biomedical subjects

B L Buff

Publications and source records attributed to B L Buff.

7 recordsLinked to original sources
PubMed1996

MR venography of left renal vein anomalies.

The examinations of 71 patients having comprehensive 2D time of flight (TOF) abdominal magnetic resonance venography (MRV) in three planes (axial, sagittal and 10 degrees offset coronal) were evaluated to assess the appearances of anomalous left renal veins as shown by MRV. Six cases of circumaortic left renal vein (CLRV) (8.5%) and one example of retro-aortic left renal vein only (1.4%) were identified, an incidence higher than that in previous computed tomography (CT) studies but comparable to venographic and post-mortem investigations. All retro-aortic components passed in a caudal direction to join the inferior vena cava (IVC) inferior to the anterior limb. MRV acquired in the sagittal plane was found to be most useful for identifying these variants and provided highest signal by avoidance of in-plane flow saturation effects.

Adolescent↗
PubMed1996

Stereoscopically guided characterization of three-dimensional dynamic MR images of the breast.

A workstation was used to postprocess volume-rendered three-dimensional (3D) dynamic contrast material-enhanced magnetic resonance (MR) images of a breast carcinoma and a breast adenoma. Use of a 3D cursor allowed stereoscopic interactive probing of specific voxels to quantify contrast enhancement over time, which was mapped to a gray scale that effectively displayed enhancement as a fourth dimension. This technique is generally applicable to any time-dependent 3D imaging modality.

Breast↗
PubMed1996

Automatic motion correction for breast MR imaging.

In 29 gadolinium-enhanced breast magnetic resonance (MR) examinations, breast motion prevented accurate and efficient image processing. To compensate for global rotations and translations, an automatic motion correction method with a ratio-variance minimization algorithm was used to align images at multiple time points through an iterative process. This method reduced breast motion and improved the accuracy and efficiency of lesion detection.

Adult↗
PubMed1994

Steps in the evolution of extracranial time-of-flight MR angiography.

Magnetic resonance (MR) angiography is not a set technique but is constantly evolving. This article illustrates changes in image quality in extracranial MR angiography that have been achieved over the past few years by the introduction of several technical developments. Images from patients examined at intervals of 12 months or more demonstrate the improvements in image quality that have resulted from these technical changes. These include bandwidth optimization for operation at 1.0 T and changes in flip angle section thickness, repetition time, and echo time. Improved image quality was assessed with objective measures of contrast-to-noise and signal-to-noise ratios. The cases illustrated show the use of MR angiography to evaluate the portal or systemic veins in patients being evaluated for liver transplantation, venous occlusion, and other venous disease. Improvements in image quality are subjectively apparent and emphasize the importance of keeping pace with technical improvements in MR angiography.

Humans↗
PubMed1994

Intraocular silicone oil: in vitro and in vivo MR and CT characteristics.

PURPOSE: To describe the CT and MR characteristics of intraocular silicone oil (polydimethylsiloxane), which is used with increasing frequency to treat complicated retinal detachments. METHODS: CT was performed on a silicone oil/water phantom and on a patient with retinal detachments secondary to cytomegalovirus retinitis, treated by bilateral intraocular injections of silicone oil. CT appearance and CT number of silicone oil were evaluated. Proton MR spectroscopy was performed with a 200-MHz spectrometer on a sample of polydimethylsiloxane within a tube of deuterated water. MR imaging was performed on a silicone oil/water phantom and on two patients with retinal detachments treated with silicone oil injection. RESULTS: Silicone oil is relatively radiodense; its CT attenuation is approximately 130 HU. On spectroscopy, silicone oil gave a single peak at 0.33 ppm. Relative to water silicone oil was hyperintense on T1-weighted images and hypointense on spin-density and T2-weighted images. Estimated T1 and T2 were 716 msec and 68 msec, respectively. Chemical shift artifacts were seen on MR images and were exaggerated when a narrow sampling bandwidth was used. In clinical cases spectral saturation pulses normally used for lipid suppression could be adjusted to saturate only the silicone resonance; in this way, the chemical shift artifact was eliminated. CONCLUSION: Intraocular silicone oil has unique imaging characteristics with which radiologists must become familiar. These characteristics include high attenuation on CT and hyperintensity on T1-weighted MR, both of which may mimic hemorrhage. Elimination of the prominent chemical shift artifact on MR with selective saturation of the silicone resonance improves evaluation of the globe.

AIDS-Related Opportunistic Infections↗
PubMed1994

Bacterial and viral parenchymal infections of the brain.

Magnetic resonance imaging (MRI) has been proven to aid in the early detection and diagnosis of parenchymal infections of the brain. Pyogenic brain abscess, herpes encephalitis, Listeria rhombencephalitis, and Rasmussen's syndrome are examined in this article. Imaging characteristics, epidemiology, clinical presentations, therapies, and pathologic findings are discussed.

Bacterial Infections↗