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Biomedical subjects

R W Hobson

Publications and source records attributed to R W Hobson.

At least 163 records · Page 9Linked to original sources
PubMed1981

Oculoplethysmography and pulsed Doppler ultrasonic imaging in diagnosis of carotid arterial disease.

The individual and combined diagnostic accuracy rates for fluid-filled oculoplethysmography and pulsed Doppler ultrasonic imaging in the detection of extracranial carotid artery insufficiency were calculated. Results of the two techniques were compared with those of contrast arteriograms which were available for 109 patients, 210 arteries, for computations of sensitivity and specificity. Sensitivities for oculoplethysmography and ultrasonic imaging were 84 and 87 per cent, while specificities were 87 and 81 per cent, respectively. These values were not significantly, p greater than 0.05, different. Results of oculoplethysmography and ultrasonic imaging agreed in four-fifths of the arteries, producing a sensitivity of 98 per cent and a specificity of 97 per cent. In the remaining arteries, the results of the two tests did not agree, resulting in a sensitivity of 71 per cent and a specificity of 79 per cent. Fluid-filled oculoplethysmography and pulsed Doppler ultrasonic imaging are diagnostic tests of comparable accuracy which, when used together, provide accurate hemodynamic and anatomic information in the diagnosis of extracranial carotid arterial disease.

Adult↗
PubMed1981

Real-time B-mode ultrasonography of the femoral arteries: comparison to contrast arteriography.

Forty-five patients with symptomatic peripheral vascular disease were studied with a high-resolution, real-time B-mode echo imaging system for visualization of the femoral arteries. Common femoral and superficial femoral arteries were visualized in over 88 per cent of cases, whereas the profunda femoris artery was demonstrated in only about one-third of cases. Stenotic lesions (+ or - 20% of arteriographic assessment) were identified in two-thirds of cases. Prostheses and grafts in the proximal and medial cases. Prostheses and grafts in the proximal and medial thigh were well visualized. Anatomic information provided by B-mode imaging will complement functional assessments of lower extremity vascular insufficiency.

Aged↗
PubMed1980

Below-knee bypass for limb salvage. Comparison of autogenous saphenous vein, polytetrafluoroethylene, and composite dacron-autogenous vein grafts.

Autogenous saphenous vein was used preferentially for 92 below-knee bypass procedures (44 femoral-distal popliteal and 48 femoral-distal tibial or peroneal) performed for limb salvage in 87 adult male patients during a 30-month period of study. When a saphenous vein was unavailable or of unsuitable length or diameter, we randomly used expanded polytetrafluoroethylene (PTFE) and composite Dacron-autogenous vein (DV) grafts. With good run-off, all grafts have remained patent. However, with poor run-off, cumulative patency by the life table method decreased to 54% for autogenous saphenous vein and 45% for PTFE, which was not significantly different. All composite DV grafts used with poor run-off became occluded within the first ten months of the study. We continue to recommend use of autogenous saphenous vein for revascularization of the ischemic lower extremity. When a suitable saphenous vein is unavailable, PTFE is a satisfactory alternative graft that is superior to composite DV grafts.

Aged↗
PubMed1980

Capabilities and limitations of pulsed Doppler sonography in carotid imaging.

Pulsed Doppler ultrasonic imaging of the extracranial carotid arteries was performed in 118 patients (226 arteries) in whom selective contrast arteriograms were available for comparison to ultrasonic images. Specificity for the detection of normal and stenosis less than 50% was 84%, whereas sensitivity for detecting stenosis greater than 50% and occlusion of the internal carotid arteries was 89%. Overall accuracy was 85%. Capabilities and limitations in the use of the technique are presented in selected case reports.

Adult↗
PubMed1980

Operative confirmation of Doppler ultrasound in evaluation of intestinal ischemia.

The prediction at operation of viability of ischemic intestine frequently is difficult and has resulted in recommendations for reoperation to assess intestine of questionable viability. This report describes the use of the Doppler ultrasonic flowmeter in three patients with ischemic intestine caused by acute superior mesenteric arterial thrombosis. Reliability of the Doppler technique was confirmed at second-look operations in each patient.

Aged↗
PubMed1980

Comparison of pulsed Doppler and real-time B-mode echo arteriography for noninvasive imaging of the extracranial carotid arteries.

Accuracy and clinical applications of noninvasive imaging of the extracranial carotid arteries were compared using pulsed Doppler and real-time B-mode ultrasonography. During the period December, 1977, to February, 1979, 530 ultrasonograms (265 patients) were performed. Angiographic correlations were available in 90 patients (172 arteries) using the pulsed Doppler technique, and both techniques were employed in 43 patients (84 arteries). Greatest accuracy with pulsed Doppler ultrasonography occurred in confirmation of normal vasculature (73%) and diagnosis of occluded internal carotid arteries (96%). Estimation of the percentage of stenosis was less accurate; however, this determination could be made somewhat more accurately by B-mode ultrasonography. Incidence of false positive and negative results for the pulsed Doppler technique was 11% and 14%, respectively, whereas for the corresponding incidence for B-mode imaging it was 11% and 59%. The higher incidence of false negative results with the B-mode technique related to its inaccuracy in diagnosis of occlusion (18%). Current clinical applications of carotid ultrasonography include confirmation of normalcy and diagnosis of occlusion, visualization of atheroslerotic plaques with characterization of their size and ultrasonic morphology, and an anticipated reduction in the requirements for contrast arteriography in selected patients.

Aged↗
PubMed1979

Determination of intestinal viability by Doppler ultrasound.

The Doppler ultrasonic flowmeter was used to determine intestinal serosal and mesenteric blood flows in 130 patients who underwent abdominal aortic vascular procedures and in 14 patients who underwent general surgical procedures. Temporary occlusion of the inferior mesenteric artery (IMA) during aortic surgery resulted in the absence or marked diminution of collateral blood flow over the left side of the colon in eight patients. One patient had the flow in the IMA preserved by proper placement of an end-to-side aortofemoral Dacron prosthesis, whereas the other seven patients underwent replantation of the IMA into the Dacron prosthesis. All patients did well postoperatively. In the 14 general surgical patients, intestinal viability and collateral mesenteric blood flows were determined, which demonstrated that the presence of audible arterial blood flow correlated with ultimate bowel viability. We recommend the use of the Doppler ultrasonic flowmeter in abdominal aortic revascularization procedures to determine the need for IMA reconstruction as well as in general surgical procedures where the surgeon desires a more objective assessment of intestinal viability.

Aorta, Abdominal↗
PubMed1979

Atherosclerotic aneurysms of the subclavian artery.

The case reports of three adult men, in whom four atherosclerotic aneurysms of otherwise normal subclavian arteries were detected in the absence of thoracic outlet syndrome or a history of trauma, are detailed. Two patients complained of supraclavicular discomfort--one having a history suggestive of peripheral arterial emboli and the other was asymptomatic. These aneurysms can be resected safely using a supraclavicular incision with resection of the medial clavicle. In cases requiring more proximal arterial control, median sternotomy is advisable. Our one patient with bilateral atherosclerotic aneurysms appears to be the first such reported case in the surgical literature.

Aneurysm↗
PubMed1978

Acute hemodynamic effects of lumbar sympathectomy.

Lumbar sympathectomy increases total limb blood flow after aortofemoral bypass in a high percentage of cases. This was true in eleven of fourteen extremities (78.6 per cent) in our series even though no specific selection criteria for entry into the study, other than the need for aortofemoral bypass, were used: that is, patients were entered into the study irrespective of preoperative ankle/arm pressure indexes or results of hyperemia testing. Overall, flow rates after sympathectomy was added to aortofemoral bypass were 1.55 times greater than after aortofemoral bypass alone. This degree of augmentation of flow may be important, particularly in cases of limited outflow.

Aged↗