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Biomedical subjects

I M Morrow

Publications and source records attributed to I M Morrow.

11 recordsLinked to original sources
PubMed1994

Carotid artery stenosis: a prospective comparison of CT angiography and conventional angiography.

OBJECTIVE: The purpose of this study was to prospectively compare CT angiography with conventional angiography for detecting stenosis at the carotid bifurcation. SUBJECTS AND METHODS: Thirty-five patients referred for evaluation of carotid artery disease were studied with conventional angiography followed by CT angiography 4-24 hr later. Seventy carotid arteries were studied. CT angiograms were acquired by using 40-sec spiral scans with a 2-mm/sec table speed, 2-mm beam collimation, and IV iodinated contrast material injected at 2.5 ml/sec. Studies were interpreted on the CT workstation by using three-dimensional shaded surface objects and multiplanar reformations requiring 10-15 min per artery. The conventional and CT angiograms were interpreted by separate observers who did not know the results of the other imaging study. The degree of stenosis was determined by using the guidelines of the North American Symptomatic Carotid Endarterectomy Trial collaborators. Each artery was categorized as normal, mildly stenosed (1-29%), moderately stenosed (30-69%), severely stenosed (70-99%), or occluded. RESULTS: The degree of carotid artery stenosis on the CT angiograms correlated well with that seen on the conventional angiograms (r = .928, p < .001). With CT angiography, all occluded internal carotid arteries were correctly identified, and no arteries were wrongly classified as occluded. The degree of stenosis was overestimated on CT angiograms by greater than 10% in 16 arteries, especially when calcified atherosclerotic plaque was present. In some of these cases, the severity of the stenosis was underestimated on the conventional angiograms. All arteries, except one, with severe disease seen on conventional angiograms were correctly classified on the basis of the results of CT angiography. CONCLUSION: Results of CT angiography had a high degree of correlation with results of conventional angiography in the evaluation of carotid artery stenosis. CT angiography is multiplanar and allows differentiation of calcified plaque from contrast material, which provides information about plaque calcification, ulceration, and size that cannot be obtained with conventional angiography.

Aged↗
PubMed1989

Treatment of liver tumors with yttrium-90 microspheres alone.

Fifteen patients with liver metastases and one patient with hepatoma were treated by infusing 15 microns diameter plastic microspheres containing yttrium-90 into the hepatic artery. Twenty additional patients were screened but were found to be unsuitable for treatment. Follow-up angiography was done in 13 of the 16 treated patients. In five patients there was a reduction in tumor volume by more than 50% and in another two patients there was a smaller reduction. In six patients gastritis or gastric ulceration occurred and in three this was demonstrated to be due to unintended infusion of microspheres into the gastric circulation. For patients treated with yttrium-90 microspheres, mean survival time after referral was 62 weeks and in the untreated group it was 30 weeks, although this difference was not significant. We conclude that yttrium-90 microspheres alone can effect reduction in the size of liver tumors in some patients in whom their use is feasible.

Follow-Up Studies↗
PubMed1988

The relationship of brachiocephalic vessel atheroma to transient ischemia of the brain and retina.

The relationships between transient cerebral and retinal ischemic symptoms and brachiocephalic angiographic findings were studied in 464 patients. The arterial abnormalities were more often bilateral than the symptoms suggested. Normal angiographic appearances were common, although abnormal arteries in patients without related symptoms were also common. When stenosis of the carotid system was 75 per cent or more, there was a strong correlation with symptoms.

Adult↗
PubMed1987

The value of combined pulsed-Doppler and high-resolution real-time sonography of the extracranial carotid system.

Duplex carotid sonography (DCS) (high-resolution real-time with combined pulsed Doppler) was performed in 374 symptomatic patients. Biplane angiographic correlation was available in 172 extracranial carotid systems. Degree of stenosis was estimated by the Doppler spectrum and by real-time appearances and categorized as: normal; less than 10% diameter reduction; 10-49% diameter reduction; 50-99% diameter reduction; or occlusion. The overall accuracy of sonography was 88%. Normal arteries were identified with a specificity of 96% and a positive predictive value of 97%. Hemodynamically, significant lesions were differentiated from less severe disease with an accuracy of 95%, a positive predictive value of 87%, and a negative predictive value of 100%. Occlusions were identified with a sensitivity of 80% and a positive value of 91%. Duplex sonography is an accurate, noninvasive method of evaluating the extracranial carotid system.

Angiography↗
PubMed1985

Percutaneous removal of upper urinary tract calculi: experience with ultrasonic lithotripsy.

From October 1983 to March 1985, the authors removed upper urinary tract calculi percutaneously in 102 patients. In 89 patients, stones required disruption with an ultrasonic lithotriptor before removal. Fifty-two patients had a stone in the renal pelvis and 20 had calyceal stones only; 21 had stones at both sites and 9 had a stone in the upper ureter. Complete removal of all stone material was achieved in 67 of 68 patients with a solitary calculus, in 13 of 26 with multiple calculi and in 6 of 8 with ureteric calculi. Complications were minimal; three patients had pulmonary edema postoperatively as a result of excessive absorption of irrigating fluid, and one patient sustained a perforation of the descending colon. The mean postoperative hospital stay was 6.8 days and patients were able to return to work a few days after their discharge from hospital. Percutaneous stone removal is a safe and effective procedure and is the surgical procedure of choice for the removal of upper urinary tract calculi.

Adult↗
PubMed1984

Ocular and cerebral ischemic mechanisms in disease of the internal carotid artery.

Stenosis of the internal carotid artery reduces the flow velocity in the ophthalmic artery. Lowered velocity permits increased red cell aggregation and decreased red cell deformability which increases viscosity. Contrary to the theory of remotely originating emboli, this is an alternate hypothesis regarding transient attacks of ocular and cerebral ischemia. The ophthalmic artery circulation time was measured in two groups of patients. The circulation time was defined as the interval between the appearance of contrast media in the siphon of the internal carotid artery and in the ocular choroid. The measurement was made on 151 angiograms of 108 subjects. These vessels were normal. An additional 76 patients had 108 angiograms which showed various amounts of internal carotid artery stenosis. These 76 patients had transient ischemic attacks; retinal, cerebral, or both. There is a significant difference in the ophthalmic artery circulation time in the two groups. The slowing in the ophthalmic artery is related to the degree of internal carotid artery narrowing. The circulation time in a cerebral branch of the internal carotid was not measured. It is presumed that stenosis of the internal carotid artery would have the same effect on a cerebral artery as on the ophthalmic artery.

Blood Circulation Time↗
PubMed1982

Carotid artery spasm. A cause of postendarterectomy thrombosis?

Carotid endarterectomy is generally regarded as a durable repair, with a low incidence of postoperative thrombosis. However, unexpected, inexplicable occlusions and pressure-flow aberrations have been reported to occur during the period immediately after operation period. We studied 245 operative angiograms obtained during a series of 335 carotid endarterectomies. Among the various defects noted were 24 instances of mild to severe spasm of the middle and distal extracranial carotid artery. This spasm was remote from the endarterectomy site and often was entirely beyond the field of operative exposure. Early and late postoperative angiograms demonstrated that this may be a transient phenomenon, and repeated intraoperative films documented that spasm may progress without further direct instrumentation of the involved segment. The patient who demonstrated the most severe spasm later suffered immediate postoperative occlusion and stroke despite a technically satisfactory repair.

Carotid Artery Diseases↗