Biomedical subjects
Publications and source records attributed to D O Cosgrove.
Echogenic rings in the periphery of renal pyramids were seen in the kidneys of six patients. This appearance is described and is correlated with abdominal radiography or computed tomography (CT) scans, serum calcium levels and, in one patient, autopsy. The findings suggest that echogenic rings are one of the earliest signs of nephrocalcinosis even in the absence of plain radiographic changes.
For the purpose of assessing and comparing the practical performance of various specific approaches to quantitative tissue characterisation, three sets of performance criteria are proposed, relating respectively to contrast resolution, spatial resolution, and speed of presentation. In each case numerical performance targets are suggested: in particular that spatial resolution should preferably be within a linear factor of three of the best achievable anatomical resolution of the associated imaging techniques and that presentation speed should be 'real time' (i.e. about 10 Hz). In the light of these criteria and performance targets the main existing approaches to ultrasonic tissue characterisation are then considered. These are classified in two groups: first those approaches based on measurements of bulk properties of tissues and secondly those related to parameters of the structural organisation of tissues. Examination of available evidence suggests that the latter group are more promising than the former. Finally it is argued that ultrasonic methods of tissue characterisation have substantial practical potential but that the realisation of such potential is contingent on achieving consensus on choice of a single, optimised and generally applicable approach that would carry with it the linked benefits of industrial standardisation and broad sharing of clinical experience.
The color Doppler signals in 60 patients with breast masses were assessed subjectively, and a regional grading method was developed for quantitation of displayed blood vessel density. Among 21 patients with breast carcinoma, moderate or high flow was demonstrated in all but one, with an average of 0.5 vessels per square centimeter and color pixels occupying 12.2% of the image area. Among 33 patients with benign disorders, no flow was demonstrated in 25 and slight to moderate flow was seen in five, with an average of 0.01 vessels per square centimeter, occupying 0.8% of the image area. Cancers as small as 10 mm in diameter were positive for flow. High-velocity flow was seen only in malignancies; it was observed in four cases and may have been due to arteriovenous shunting. Flow was less readily detected in recurrent tumors; two of seven tumors were weakly positive. Color Doppler shows promise as an adjunct to ultrasound imaging in the differential diagnosis of breast lesions.
We have carried out a prospective study on the impact of computed tomography (CT) and ultrasonography (US) on the management of patients with carcinoma of the ovary. Seventy-eight CT and 88 US scans were performed on 94 patients. Clinicians decided patient management prospectively at the time the CT and/or US was ordered. Clinical assessment differed from the result obtained by CT or US in 45% of cases (35/78 and 40/88, respectively). CT and US altered patient management in only a minority of cases (14/78, 18% and 9/88, 10% respectively). Even when the scan and clinical assessments differed, management was only altered on 14/35 (40%) occasions after CT and on 9/40 (23%) occasions after US, a difference which was not significant. In patients with clinically undetectable disease, management was altered by CT on 17% of occasions and by US on 10%. We conclude that in patients with carcinoma of the ovary CT and US alters patient management in a minority of cases. In view of current financial restrictions in health care, clinicians should be more selective in the use of these imaging techniques. Furthermore, we recommend that similar prospective studies are performed for other clinical situations.
An analysis is made of the kinetics of human liver parenchyma in response to mechanical impulses arising in the heart and aorta, and the results are applied to predicting the time course of the correlation between two time-separated A-scans derived from various regions of the liver. Such predictions are found to correspond well with data derived clinically, both from volunteers and from patients with liver metastases, using a commercial, real-time sector scanner. On the basis of Fourier spectral features of the clinically derived correlation patterns, a clear quantitative separation was demonstrated between the kinetic response of three classes of tissue: normal liver in volunteers, metastatic deposits in liver of cancer patients, and histologically normal liver regions in the same patients.
Semi-quantitative diagnostic features were extracted by a visual analysis of the echographic images of selected cases of breast disease and the results stored in a computer database. The long term aim is to create an environment suitable for the use of multivariate statistical methods systematically to evaluate ultrasound interpretive criteria and diagnostic performance in relation to factors such as scanning instrumentation and other diagnostic techniques. Eventually it is hoped that it will be possible to generate a system for computer assisted diagnosis and training. The results of this pilot study serve to demonstrate the feasibility of the approach and a univariate analysis is used to provide a preliminary ranking of diagnostic features. Features found to be particularly valuable for distinguishing benign from malignant solid lesions were the regularity and definition of the edge of the tumour, the mobility of the tumour and measures of echo heterogeneity within and posterior to the tumour mass.
The results of computed tomography (CT) and other imaging techniques performed on 70 patients who were investigated for suspected recurrent carcinoma of the cervix are reported. Recurrent disease was present in 39 patients. In 29, there was local recurrence with or without distant metastases and there was distant recurrence only in 10. Computed tomography correctly assessed the presence of local recurrent disease in 85% of patients. Six equivocal, two false positive and two false negative CT examinations in the assessment of local recurrence were due either to difficulty in differentiating recurrent disease from changes following radiotherapy, or to the failure of CT to detect small areas of local recurrent disease. Ultrasound and lymphangiography each detected recurrence in one patient which was missed by CT, but this was the most reliable technique for the detection of both local and distant recurrent disease.
A rounded or ovoid midline structure with mean measurements of 1.30 cm x 1.33 cm x 0.96 cm in longitudinal, transverse and antero-posterior dimensions was routinely imaged at the bladder base in 97 female patients on pelvic ultrasound examination. Its position and appearance are reminiscent of a smaller version of the male prostate, and it has been dubbed the "female pseudoprostate". It appears to correspond with the external rhabdo-sphincter of the bladder. Its rounded shape may be confusing but it should not be misread as pathological.
Whereas the portal veins and hepatic arteries supply the right and left lobes of the liver, the hepatic veins pass along the boundaries between the lobes and segments. Their positions can therefore be used to identify liver segments and allow a precise description of the position of focal lesions. In 104 subjects without liver pathology, the hepatic veins were demonstrated in 101 and followed the classical pattern in 87. Absent and accessory veins were encountered.
Real-time ultrasound scanning is a rapid and readily available way of detecting pericardial fluid. We have successfully and safely used real-time ultrasound scanning to plan and guide pericardiocentesis on 24 occasions in the last 2 years, in each case for therapeutic purposes in patients with malignant pericardial effusions. The procedure may be readily performed in the ultrasound department or on the ward. We advise the use of real-time ultrasound guidance in all instances of pericardiocentesis.
A method is described for quantifying tissue movement in vivo from the computation of correlation coefficient between pairs of A-scans with appropriate time separation. The method yields quantifiable and repeatable secondary patterns of soft tissue movement in response to primary cardiac movement in a given subject, shows consistently different results as between normal livers and a variety of abdominal tumours, and is sensitive to either progress or therapeutically-induced regression of malignant disease. While the results reported here have been obtained using somewhat simple and crude equipment, the method is well suited to implementation on a commercial real-time scanner.
Ultrasound (US) was compared with surgical findings in 98 patients with carcinoma of the ovary undergoing follow-up laparotomy after chemotherapy. US had an overall accuracy of 94% in the pelvis, with only small and sheetlike lesions escaping detection. It was more sensitive than clinical examination. Overall accuracy for the liver was 91% with very few false-positive results. For the peritoneal cavity in general, however, accuracy was low, with even large masses escaping detection. Ascites is reliably detected (accuracy of 97%) but is a poor indicator of peritoneal involvement. US is a useful noninvasive complement to laparoscopy in the follow-up of patients with carcinoma of the ovary.
Four cases of focal sparing in otherwise diffuse fatty infiltration of the liver are reported. The characteristic features are described as shown at sonography, computed tomography (CT) and scintigraphy. It is emphasised that, with ultrasound, if the increased echogenicity of the majority of the liver is not appreciated, then the area of normal hepatic parenchyma may be misinterpreted as a pathological hypoechoic lesion.
One hundred and sixty-four patients with Graves' disease were treated with low-dose radioiodine (2 mCi), with a mean follow up of 4 1/2 years. At this time 74 (45%) were euthyroid having had a single dose, with a total of 131 (80%) being controlled with one or more doses. Three (2%) were still toxic but their mean follow up was only 3 years. Thirty (18%) were rendered hypothyroid, two-thirds of these after a single dose of 2 mCi 131I. The one-year incidence of hypothyroidism was 6%, with an incidence at 6 years of 20%. Previous surgery, medical treatment and thyroid antibody status appeared to have no influence on the outcome.
Experience using low-dose radioiodine given six-monthly instead of yearly in hyperthyroid patients with Graves' disease is reported. One hundred and thirty-five patients have been treated over a three-year period with 74 MBq (2 mCi) doses of 131I. Thirty-eight percent were controlled with a single dose. Those patients requiring more than one dose were treated with a further 74 MBq (2 mCi) 131I at six-monthly intervals until euthyroid. Using this approach, 46% were euthyroid one year after starting treatment, and 75% were euthyroid at two years. The incidence of hypothyroidism following treatment was 2.2% at one year, with a yearly incidence thereafter of 4-6%. Six-monthly scheduling of low-dose radioiodine in Graves' disease can reduce the time taken to become euthyroid, compared with conventional yearly low-dose treatments. Further follow up is required to confirm the present low incidence of hypothyroidism following treatment.
Eating might be expected to change vessel size within the portal venous system. The diameters of the portal and superior mesenteric veins were measured in thirteen normal individuals using B-mode ultrasound, initially fasting and then following a meal. We have shown a 50% increase in the diameter of both these vessels occurring between thirty minutes and one hour after a meal. The significance of this is discussed.
A densely echogenic line is seen connecting the right portal vein and the neck of the gallbladder on longitudinal views in at least 70% of sonograms. The origin of the line has been taken to be the fissure between the right and left lobes of the liver, but no documentation has been provided. Intact liver specimens were studied in a water bath; metallic markers were placed to coincide with the line under real-time guidance. The line does, indeed, correspond to the interlobar fissure. Factors affecting visualization include position of the gallbladder neck and orientation of the fissure as well as fat deposition within the fissure.