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Biomedical subjects

G A Irwin

Publications and source records attributed to G A Irwin.

At least 19 recordsLinked to original sources
PubMed1984

Distribution of placental grade in high-risk gravidas.

One hundred twenty-eight high-risk gravidas and 62 normal gravidas who had undergone placental sonography were compared retrospectively according to placental grade, risk category, and stage of pregnancy at the time of the examination. Pregnancies ranged from 28 weeks of gestation to term. For analysis, the group of high-risk patients was subdivided into four categories representing specific disease states: chronic hypertension and/or preeclampsia, intrauterine growth retardation, maternal diabetes, and Rh sensitization. To eliminate gestational age bias, both the normal group and the high-risk subgroups were further subdivided into preterm and term pregnancies. Placental grade distribution was similar between the high-risk group overall and the normal group, but specific disease entities were associated with widely varying distributions of placental grade. In particular, hypertension and intrauterine growth retardation showed a strong correlation with accelerated placental maturation, whereas diabetes and Rh sensitization were associated with delayed maturation of the placenta. These differences were more pronounced in the preterm population.

Calcinosis↗
PubMed1983

Work in progress: detection of deep venous thrombosis with 99mTc-sulfur colloid.

Scintigrams of the leg were obtained following antecubital venous injection of 99mTc-sulfur colloid (SC) in 25 patients with suspected deep venous thrombosis. Contrast venograms were taken following the scan in all cases. Of 14 patients with confirmed deep venous thrombosis, 11 had positive scans. Of 11 patients with normal venograms, 10 had negative scintigrams. The simplicity of 99mTc-SC venography and its high rate of accuracy (84% in this series) suggest that it may be useful as a relatively noninvasive means of identifying deep venous thrombosis of the leg.

Adult↗
PubMed1978

Drip infusion urography with meglumine iodamide.

In a double-blind study of 283 patients (140 given iodamide and 143 diatrizoate), meglumine iodamide 24% produced a significantly greater degree of opacification than meglumine diatrizoate 30% (P less than 0.01 to P less than 0.001) in the renal calyces during the early phase of drip infusion pyelography. The agents were infused at a dose of 4.5 ml/kg, up to a maximum volume of 300 ml, over a period of about 10 min. The incidence and nature of laboratory abnormalities and clinical adverse reactions produced by the drugs were similar. No severe reactions occurred. The apparent superiority of the iodamide solution in the early stage of excretion, despite its lower iodine content, may be due to the partial secretion of iodamide by the renal tubules, as observed in other studies.

Adolescent↗
PubMed1976

Radiographic evaluation of patency of interposition mesocaval shunts.

The technique of side-to-side mesocaval anastomosis with the interposition of a prosthetic graft was described in 1970. We report the result of venographic evaluation of patency of this type of shunt in our patients. Demonstration of an unoccluded graft; resistance to retrograde injection of dye against the blood stream into the superior mesenteric vein; rapid clearing of dye from superior mesenteric vein following injection and "lamellar flow defect" in the vena cava above the site of anastomosis during vena cavogram, were considered criteria of patency of the interposition mesocaval shunt.

Blood Vessel Prosthesis↗
PubMed1976

A computer assisted radiological reporting system.

The authors report their experience with a commercially available computerized diagnostic reporting system. The system has been in operation more than 36 months and processes more than 95,000 cases annually. Dictation is needed for only 13% of emergency room cases and 23% of in-patient cases. Savings in overtime and increased efficiency have resulted. The system can be adapted to other computerized systems within the x-ray department. Acceptance by staff and residents has been good.

Diagnosis, Computer-Assisted↗
PubMed1976

Digital low-pass filtering.

Random noise beyond the maximum signal frequency of the imaging system can be removed by low-pass filtering without compromising signal transmission.

Brain↗