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R C Benson

Publications and source records attributed to R C Benson.

138 records · Page 8Linked to original sources
PubMedDate not supplied

The motion artifact suppression technique (MAST) in magnetic resonance imaging: clinical results.

The Motion Artifact Suppression Technique (MAST) is a method which uses a series of gradient echos that are computed to cancel velocity, acceleration and pulsatility components of involuntary motion in MR imaging. A total of 916 patient studies were performed over a nine month period using MAST sequences with a TE 40, 60, 80, 100, 120, and 26/112. There was considerable improvement in long TR, long TE images. Cerebrospinal fluid flow artifacts were reduced. Body and spine images had reduced flow and respiratory artifacts. Spin rephasing in blood vessels caused increase intraluminal signal. This might be useful for cardiovascular imaging.

Blood Circulation↗
PubMedDate not supplied

Magnetic resonance imaging of bone after radiation.

Magnetic resonance imaging (MRI) was performed in 22 patients at various times (0-3) years) following radiation therapy to the spine. T1 and T2 weighted images were obtained at 0.5 Tesla. Increased signal was seen after 800-6000 rads (8-60 Gy). Marrow effects corresponded to radiation ports. Recurrent tumor was clearly separated from fatty replacement. This was much better seen on T1 weighted images. Five patients that had MRI during their course of radiotherapy (XRT) did not have increased signal on T1 images of the bone marrow. The earliest fatty marrow change was seen nine days following completion of 3000 rads (30 Gy) XRT over one month's duration. One patient who received 800 rads (8 Gy) to the upper thoracic spine for eosinophilic granuloma had no radiation effects on MRI when imaged 16 days following completion of XRT given over five days. Fatty marrow change was seen in this patient on MRI six months later. MRI was particularly useful in defining the extent of prior radiation effects when repeat therapy was needed.

Adolescent↗
PubMedDate not supplied

Cancer of the ovary.

Explore the source record for details and available documents.

Adolescent↗
PubMedDate not supplied

Migration and granulomatous reaction after periurethral injection of polytef (Teflon).

Although patients with urinary incontinence have been treated successfully by periurethral injection of polytef paste, this study in continent animals demonstrates migration of polytef particles from the injection site. We injected polytef paste periurethrally into female dogs and male monkeys. Particles were found at 50 to 70 days in pelvic nodes in six of seven animals and lungs in four of seven (the kidneys and brain were not studied); and at 10 1/2 months in pelvic nodes, lungs, and brain in seven of seven; kidneys in four of seven; and spleen in two of seven. X-ray microanalysis confirmed that the particles were polytef. At 10 1/2 months, polytef granulomas were found at all injection sites and some sites of distant migration. Since these granulomas signify chronic foreign-body reaction, we believe that until the long-term effects in humans are known, polytef paste should not be used in children or young adults with normal life expectancy.

Animals↗
PubMedDate not supplied

Scanning electron microscopy after cytologic examination of urinary cells: lack of diagnostic advantage using combined microscopy.

A simple method for combined light microscopy (LM) and scanning electron microscopy (SEM) of urinary sediment is described. Spontaneously voided cells were routinely collected onto a filter for cytologic study. Individual cells were photographed and demarcated by an ink grid pattern and puncture marks in the filter. The filter was prepared for SEM. The cells that were studied by LM could be readily located and examined by SEM. This study showed the importance of identifying individual cells before observation by SEM since cells with similar appearances by LM may have markedly different features by SEM, and vice versa. The results obtained in a series of patients with transitional-cell bladder carcinoma indicate that degenerative changes in voided urothelial cells negate the utility of SEM as a routine screening tool.

Carcinoma, Transitional Cell↗