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Biomedical subjects

W G Ritchie

Publications and source records attributed to W G Ritchie.

At least 19 recordsLinked to original sources
PubMed1986

Acquired tracheomegaly in very preterm neonates.

Proximal airways are compliant structures at early gestational ages and may be susceptible to pressure-induced deformation following prolonged ventilatory support. Sixteen neonates (mean +/- SD gestational age, 27.0 +/- 0.6 weeks; mean +/- SD birth weight, 847 +/- 68 g) were studied to assess tracheal volume deformation. The neonates received ventilatory support for a mean +/- SD duration of 25.4 +/- 4.9 days. During this period the maximum peak inspiratory pressures ranged from 15 to 25 cm H2O, and respirations ranged from 20/min to 60/min. These neonates were studied at seven days postextubation and were individually matched for body weight with 16 nonventilated neonates. The width of the tracheal air column was measured at the lower border of the first thoracic (T-1) and third thoracic (T-3) vertebrae. The average tracheal width (average of T-1 and T-3) was significantly (38%) wider in the ventilated group, and the mean +/- SD tracheal width values were 3.79 +/- 0.29 mm, as compared with the control values of 2.74 +/- 0.31 mm. Based on these data it was estimated that the tracheal volume was 91% greater in the ventilated group. These observations demonstrate tracheal volume deformation and acquired tracheomegaly in neonates who have received mechanical ventilatory support. In addition to increased dead space ventilation, these findings also indicate underlying mechanical deformation of the tracheal wall.

Barotrauma↗
PubMed1986

Sonographic evaluation of normal and induced ovulation.

The adult premenopausal ovary exists in a dynamic state of flux, with ovarian position, size, activity, and structure constantly undergoing changes. Pelvic sonograms must be interpreted with knowledge of the stage of the menstrual cycle and the expected normal range of sonographic findings, because features that are normal in one phase may be abnormal in another. Only against this background knowledge can the challenging task of interpretation of pelvic sonograms be successfully performed. US also plays an increasingly important role in monitoring ovulation induction and alternative methods of fertilization and has improved pregnancy rates by distinguishing between the presence of one or more mature follicles as opposed to a cohort of immature follicles, suggesting the possibility of multiple ovulation with the risks of hyperstimulation or poor pregnancy outcome from multiple gestation, indicating optimum timing of human chorionic gonadotropin administration, allowing detection and confirmation of normal follicular rupture and ovulation, indicating optimum timing of oocyte retrieval in programs of in vitro fertilization with embryo transfer (IVF-ET) or insemination programs, and assessing pathologic pelvic conditions and ovarian accessibility in IVF-ET programs. Oocyte retrieval and embryo transfer are also being performed under US guidance.

Anovulation↗
PubMed1986

Aggressive angiomyxoma: CT appearance.

Aggressive angiomyxoma is a rare benign tumor, arising in the pelvis usually presenting clinically as a perineal soft tissue mass displacing normal pelvic structures. The tumor is characterized by its locally aggressive nature and its tendency to recur after surgical resection. Although descriptions of this tumor have recently appeared in the pathology literature, to date, the radiological appearance of aggressive angiomyxoma has not been well documented. The CT scan in the following case report demonstrates the extent and location of the tumor, as well as its tendency to displace, rather than invade adjacent structures. These findings are consistent with the pathological characteristics of aggressive angiomyxoma, and therefore, can assist in its preoperative diagnosis.

Adult↗
PubMed1985

Ultrasound in the evaluation of normal and induced ovulation.

In the past several years sonography has become an invaluable research tool for the investigation of spontaneous and induced ovulation and has added to the understanding of folliculogenesis and reproductive endocrinology. In practical terms, in ovulation induction sonography assists in the evaluation of the number and distribution of follicles, necessary for adequate interpretation of estrogen levels. Although there is no ideal size when it can be assumed that a follicle is mature, estimation of follicle size is of value and is a good guide to the timing of hCG administration. If the follicles are extremely small or there is evidence of hyperstimulation, these observations, together with the E2 levels, may be used to decide whether a further ultrasonic examination is warranted for the assessment of follicular growth or whether the treatment cycle should be abandoned. Provided follicular size is within normal limits, the diameter of the largest follicle may also be used in IVF programs to determine when the patient should be admitted to the hospital for more intensive monitoring of follicular development and the administration of hCG. Ultrasound is also valuable in patients with only one ovary accessible to laparoscopy. Even if the largest follicle is in the inaccessible ovary, the treatment cycle does not have to be abandoned, provided that several follicles are developing in the contralateral ovary. If neither ovary is accessible laparoscopically, percutaneous oocyte aspiration offers the patient the opportunity of IVF and embryo transfer.

Anovulation↗
PubMed1982

Postmenopausal uterine fluid collection: indicator of carcinoma.

Seventeen cases of intrauterine fluid collections in postmenopausal women demonstrated by sonography were collected. Of the 17, 16 (94%) were found to have active carcinoma involving the uterine corpus or cervix. Eleven (65%) had cervical stenosis due to previous surgery, radiation therapy, or carcinoma. The fluid collected was pus, blood, or serous or serosanguineous fluid, and tumor nearly filled the dilated uterine cavity in some cases. The sonographic demonstration of a distended uterine cavity in a postmenopausal woman suggests carcinoma involving the uterus.

Aged↗
PubMed1980

A simple ultrasonic method for assessing renal size.

The relation between renal length (L) and the distance between the first four lumbar transverse processes, (4TP) as measured by sonography and intravenous urography, has been studied in 20 adults with normal urograms. The ratio of L/4TP (Mean +/- 2.S.D.) was 1.04 +/- 0.22 for sonograms and 1.25 +/- 0.26 for urograms. The possible reasons for these differences are discussed. It is suggested that measurement of the distance between the 4TP is a simple method for estimating expected normal renal size in patients referred for renal ultrasonography.

Anthropometry↗
PubMed1979

Thermographic diagnosis of deep venous thrombosis.

Two hundred patients with suspected deep venous thrombosis had thermography performed prior to ascending phlebography. Diagnostic agreement was obtained in 79%. Published diagnostic thermographic criteria were used; it was not possible to diagnose consistently limited or early thrombosis, especially in the calf muscle veins. Venous insufficiency produced the majority of false positives.

False Negative Reactions↗
PubMed1979

Thermographic diagnosis of deep venous thrombosis: anatomically based diagnostic criteria.

Deep venous thrombosis is associated with increased heat emission from involved muscle groups and deviation of blood flow from the deep to the superficial venous system. Both of these features can be documented by thermography. An appreciation of the muscular and venous anatomy of the lower limb allows recognition of predictable thermographic images reflecting involvement of various muscle groups in the leg. It is expected that these anatomically based criteria will improve the diagnostic accuracy of thermography and offer a noninvasive, easily repeatable modality of examination for the diagnosis of deep venous thrombosis.

Humans↗
PubMed1979

Effect of phlebography on 125I uptake test.

Increased 125I fibrinogen uptake counts were encountered in 30 of 55 limbs after a normal ascending phelbogram. In most cases, the abnormal 125I fibrinogen uptake test occurred within 72 hr after phlebography, and the elevated counts were most frequently seen around the ankle, with contiguous involvement of the calf seen less often. Inly three patients with positive counts subsequently became symptomatic and were treated for deep venous thrombosis. The presence of deep venous thrombosis was confirmed by repeat ascending phlebography in two of these cases. Ascending phlebography was not performed on the other positive postphlebographic fibrinogen uptake test limbs.

Fibrinogen↗
PubMed1978

Controlled trial of low-dose heparin and sulfinpyrazone to prevent venous thromboembolism after operation on the hip.

A randomized, double-blind controlled trial of low-dose heparin combined with sulfinpyrazone to prevent deep-vein thrombosis after operation on the hip was carried out. In a group of seventy-three patients after arthroplasty, postoperative thrombosis of the veins of the lower limbs occurred in 51 per cent of the control patients and in 36 per cent of the treated patients. In a fracture group of thirty patients, thrombosis occurred in 75 per cent of the control patients and in 36 per cent of the treated patients. These differences are of borderline statistical significance in the fracture group and are of no statistical significance in the arthroplasty group. However, a 36 per cent incidence of venous thrombosis in the drug-treated patients is too high to justify recommendation of the regimen tested without careful monitoring of patients by tests designed to detect thrombosis. Then, appropriate anticoagulant therapy can be instituted if necessary.

Administration, Oral↗
PubMed1975

Periosteal new bone formation developing during haemodialysis for chronic renal failure.

Periosteal new bone formation in the pelvis is reported in five patients on maintenance haemodialysis for chronic renal failure. In two of the cases the shafts of long bones were also involved. The associated radiological and biochemical findings suggest that this unusual radiological feature may be a manifestation of secondary hyperparathyroidism. In one patient in whom the plasma phosphate and calcium X phosphate [Ca X P1] product were reduced there was partial incorporation of the periosteal new bone into the underlying cortex.

Adolescent↗