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Biomedical subjects

K A Griffiths

Publications and source records attributed to K A Griffiths.

8 recordsLinked to original sources
PubMed1989

New class of pulsed Doppler US ambiguity at short ranges.

A form of range ambiguity in Doppler ultrasound has been identified. It occurs when a high pulse repetition frequency (prf) is used with a superficial range gate. "Phantom" range gates are then generated at depths beyond the desired range gate, and these may produce artifactual signals. Extremely high prf values should not normally be used, and duplex machines should be programmed to display phantom range gates wherever they fall within the displayed field of view.

Humans↗
PubMed1988

Ultrasonic characterization of splenic tissue in myelofibrosis: further evidence for reversal of fibrosis with chemotherapy.

Fibrosis in patients with myelofibrosis (MF) is seen not only in the bone marrow but also around the metaplastic foci in the spleen and liver. Following our observation of reversal of bone marrow fibrosis in MF patients treated with chemotherapy, we undertook ultrasonic splenic tissue characterization studies using sound speed measurements to assess the effect of such therapy on the splenic fibrosis. Single studies in 19 patients showed overlapping ranges among the three sub-groups classified according to the grade of bone marrow fibrosis, but the mean values in these sub-groups showed a trend towards decreasing sound speed with increasing marrow fibrosis. Sequential studies in 9 of these patients showed increased splenic sound speed with decreasing marrow fibrosis in 8 patients following treatment, with a reversal of this pattern seen in 1 patient 1-2 years post-treatment. These results suggest simultaneous reversal of fibrosis in the bone marrow and the spleen in MF patients receiving effective chemotherapy.

Bone Marrow↗
PubMed1987

Splenic blood flow measurements by Doppler ultrasound: a preliminary report.

Splenic blood flow and splenic volume were measured by Doppler and cross sectional ultrasound in 72 human subjects consisting of 61 patients with splenomegaly and 11 normal subjects. This non-invasive and relatively simple method yielded satisfactory results in 76% of the subjects studied; failures were due to obesity, debility, distorted vascular anatomy, and excessive gas in the stomach. These preliminary results suggest that the Doppler ultrasound technique is a practical clinical method for measuring splenic blood flow.

Adult↗
PubMed1987

Clinical sound speed measurement in liver and spleen in vivo.

The paper describes an implementation of clinical sound speed measurement using either a commercial water path scanner or a specially developed dual transducer real time scanner, each interfaced to a general purpose minicomputer for off-line analysis. It describes the examination technique to obtain suitable in vivo clinical data from the liver and the spleen. It develops signal processing methods to achieve clinical confidence in individual measurements. Forty-five liver patients and 46 spleen patients were examined. Sound speed was found to correlate closely with fibrosis content in both the liver and the spleen with an increase in fibrosis resulting in a decrease in sound speed. Sound speed in various pathological conditions are discussed. Clinical results of sequential examinations on patients under treatment are presented and successful monitoring of the disease status is demonstrated. The potential clinical role of sound speed measurement is suggested.

Acoustics↗
PubMed1987

Evaluation of ultrasonic attenuation in diffuse diseases of spleen and liver.

Ultrasonic attenuation has been measured using frequency domain signal processing in clinical trials of patients with liver and spleen diseases. By comparing the variance encountered in local measurements and in measurements at a number of adjoining sites, the need for averaging over large volumes of tissue to avoid the effects of large fluctuations is established. In spleens of patients with myelofibrosis, no correlation between fibrosis and attenuation was found. However it was found that variations in splenic volume were accompanied by inverse changes in attenuation, most likely due to blood pooling. A correlation was found between splenic blood flow per unit organ volume and attenuation. In cirrhotic livers, attenuation was significantly increased with fatty infiltration, but only slightly increased in livers containing minimal fat. These findings tend to reduce the probability of finding successful clinical applications for attenuation slope measurements.

Fatty Liver↗
PubMed1983

Housing for the aged: new roles for social work.

As the elderly population increases, social workers and planners of housing must coordinate efforts and combine resources as they explore new channels for meeting the housing needs of the aged. In evaluating new roles for social work in this field, three basic areas are discussed: 1) the nature of the housing problem, 2) the needs of the elderly, and 3) the role of social work in meeting these needs.

Aged↗
PubMedDate not supplied

Percutaneous control of a portacaval H-graft: description of a new device and its initial clinical application.

A percutaneously-controlled inflatable cuff which can change the diameter of a portacaval H-graft has been developed and used in 10 patients. When inflated, the cuff narrows the H-graft to increase portal pressure and reduce shunting. Use of the cuff has been of clinical significance in 3 of 7 long-term surviving patients. Narrowing the shunt improved the clinical state in 2 patients with encephalopathy, and reopening a closed shunt improved ascites in the third patient. Duplex ultrasound and deep Doppler have demonstrated an alteration of hepatic portal blood flow following inflation of the cuff after 6 months. It is concluded that further development of this controlled portacaval H-graft is warranted.

Adult↗