The diagnostic acceptability of low-bandwidth transmission for tele-ultrasound.

Ultrasound recordings were made of 100 consecutive patients attending for obstetric examination in Peterhead and 100 patients attending for non-obstetric examination in Aberdeen. Two identical video-conferencing machines were used to transmit and receive the original ultrasound images at data rates of 384 kbit/s and 128 kbit/s, thus producing a total of three tapes for each case. Four experienced observers, who were blinded to the transmission bandwidth, each viewed 300 examinations and decided whether the images were acceptable or not for diagnosis. Almost 100% of the obstetric ultrasound images on the original recordings were considered diagnostically acceptable, compared with 93% of the 384 kbit/s transmissions and 44% of the 128 kbit/s transmissions. Similarly, 99% of the non-obstetric ultrasound images were considered acceptable, compared with 87% of the 384 kbit/s transmissions and 21% of the 128 kbit/s transmissions. For the obstetric ultrasound images the intra-observer diagnostic agreement was 93% (kappa = 0.89) between the original and the 384 kbit/s transmissions, and 78% (kappa = 0.63) between the original and the 128 kbit/s transmissions. For the non-obstetric ultrasound images the respective intra-observer diagnostic agreements were 77% (kappa = 0.62) and 78% (kappa = 0.63). The quality of dynamic ultrasound images transmitted at 384 kbit/s was diagnostically acceptable, but was unsatisfactory at 128 kbit/s.

Leiomyosarcoma: computed tomographic findings.

The computed tomographic (CT) findings in 118 patients with the diagnosis of leiomyosarcoma were reviewed. The tumor masses visualized in these patients were often quite large; extensive necrotic or cystic change was a frequent finding. Calcification was not observed in these tumors. The liver was the most common site of metastasis in these patients, with marked necrosis of the liver lesions a common finding. Other manifestations of tumor spread included pulmonary metastases, mesenteric or omental metastases, retroperitoneal lymphadenopathy, soft-tissue metastases, bone metastases, splenic metastases, and ascites. The metastatic lesions were often centrally necrotic. Although the CT appearance of leiomyosarcoma is not specific, these findings, when present, suggest consideration of this diagnosis.

Sonographic evaluation of pediatric rhabdomyosarcomas.

The ultrasound examinations of ten pediatric patients with retroperitoneal or pelvic embryonal rhabdomyosarcomas were reviewed. A pattern of coarse low-, medium-, or high-level echoes was observed in these tumors. Sonolucent areas, probably secondary to necrosis or hemorrhage, were seen in the tumors of five patients. Serial examinations were performed during the course of chemotherapy and/or radiotherapy in seven patients. These studies were examined retrospectively to determine whether a specific change in the echo characteristics of the tumor occurred during therapy. No such specific change was observed in these patients. Ultrasound was useful in following tumor size and thus, response to therapy, which is important with the advent of newer, more conservative forms of therapy for rhabdomyosarcoma.

Effects of in vitro incorporation of cholesterol and cholesterol analogues into rat platelets.

Cholesterol and analogues of cholesterol bearing shorter side chains were incorporated into rat platelet membranes by incubation with sterol-rich liposomes in vitro. Cholesterol-enriched platelets showed increased aggregability to collagen compared with controls. Platelets containing the cholesterol analogues pregn-5-en-3 beta-ol and chol-5-en-3 beta-ol were even more sensitive to aggregation and could aggregate spontaneously on stirring. The size of the platelets containing pregn-5-en-3 beta-ol was markedly reduced when compared with controls in the scanning electron microscope. The results suggest that the sterol content and structure of the platelet membrane can have a critical role in maintaining the normal function of the cell.